Proceedings

International Conference

Distribution India - 1 Planning and Operation of Reliable Distribution Systems 15-16 April, 2004 Hotel Hyatt Regency, New Delhi (India)

PROCEEDINGS Chief Editor C. V. J. Varma

Associate Editors N. D. Gupta D. K. Mehta

Organized by :

Council of Power Utilities A-2/158, Janakpuri, New Delhi-110058, India Tel. # 25618472, 55455626 Fax # 25611622

ADVISORY COMMITTEE 1.

Sh. A. K. Sah Executive President, Mott Mcdonald, A-20, Sector–2, Noida

2.

Sh. Jagdish Sagar Chairman, Delhi Vidyut Board, Shakti Bhavan, Nehru Place, New Delhi-110019

3.

Sh. Dinesh Kumar Chairman and Managing Director, Andhra Pradesh Central Power Dist. Co. Ltd., APCPDCL, Hydrabad

4.

Dr. M. V. Krishan Rao Director, Global Energy Consulting Engineers Pvt. Ltd. 6-3-570/1, Diamond Block, Rockdale Compound, Somajiguda, Hydrabad

5.

Shri R. K. Narayan Former CMD, Powergrid, B-435, Sarita Vihar, New Delhi-110044

6.

Sh. S. R. Sethi Director, Delhi Power Supply Co. Ltd Shakti Sadan, Kotla Road, New Delhi-110003

TECHNICAL COMMITTEE 1.

Sh. Mata Prasad Former Advisor (Power Trans.) ABB, Distinguished Member, CIGRE, 5/100, Vinaykhand, Gomti Nagar, Lucknow-226010

2.

Sh. I. S. Jha General Manager SEF, Power Grid Corporation of India Ltd, Plot No.2, Sector-29, Near IFFCO Chowk, Gurgaon-122001

3.

Dr. N.S.Saxena General Manager, QA & I, Power Grid Corporation of India Ltd. Plot No.2, Sector-29, Near IFFCO Chowk, Gurgaon-122001

4.

Dr. M. L. Kothari Dept. of Electrical Engg. Indian Institute of Technology, Hauz Khas, New Delhi

5.

Dr. S. C. Srivastava Dept. of Electrical Engg. Indian Institute of Technology, Kanpur, IIT Post Office, Kanpur-208016

6.

Prof. P. K. Kalra Dean, Resource Planning, Indian Institute of Technology, Kanpur, IIT Post Office, Kanpur-208016

ORGANIZING COMMITTEE 1.

Sh. A. K. Sardana Chief Executive Officer, North Delhi Power Ltd., Grid Sub-Station Building, Hudson Lines, Kingsway Camp, Delhi - 110009

2.

Sh. Mata Prasad Distinguished Member CIGRE &, Former Advisor (Power Trans.) ABB, 5/100, Vinay Khand, Gomti Nagar, Lucknow-226010

3.

Sh. C. V. J. Varma Secretary General, Council of Power Utilities, A-2/158, Janakpuri, New Delhi - 110058

4.

Sh. V. K. Prasher ED (LB & C And HVDC), Power Grid Corporation of India Ltd., B-9 Institutional Area, Katwaria Sarai, New Delhi - 110016

5.

Sh. Dr. N S Saxena General Manager (Quality Assurance & Inspection), Power Grid Corporation of India Ltd., Corporate Centre, Plot No. 02, Near IFFCO Chowk, Gurgaon - 122001

6.

Sh. A. K. Sah Former CMD, NTPC and Chairman, Premier Mott Mac Donald, A-20, Sector-2, Noida-201301

7.

Sh. R. K. Narayan Former CMD, PGCIL & UPPCL, A-51, Chattarpur Enclave, Phase - 2, New Delhi

8.

9.

Ms. Chanda Saini Managing Director, Dakshin Haryana Bijli Vitran Nigam, Vidyut Nagar, Hissar-125005 Ms. Joty Arora Managing Director, Uttar Haryana Bijli Vitaran Nigam, Panchkula 134109,

10.

Sh. M. L. Saini Chairman & Managing Director, Ajmer Vidyut Vitran Nigam Ltd., Hathi Bhata, Old Power House, Jaipur Road, Ajmer 305001

11.

Sh. H. D. Charan Chairman & Managing Director, Jodhpur Vidyut Vitran Nigam Ltd., New Power House, Industrial Area, Jodhpur 342003

12.

Sh. B. N. Sharma Chairman & Managing Director, Jaipur Vidyut Vitran Nigam Ltd., Vidyut Bhawan, Janpath, Jaipur 302005

13.

Sh. D. N. Gupta Chief Engineer, NDMC, EI/2 Satya Sadan, Satya Marg, New Delhi-110021

14.

Sh. Sanjay Mitra Chairman, West Bengal State Electricity Board, Vidyut Bhawan, DJ Block, Sector II, Salt lake City, Kolkata 700091

15.

Sh. Manoj Shrivastava Member (D) East Zone CMD (MPMKVV Co. Jabalpur), Madhya Pradesh State Electricity Board, Shakti Bhawan, Vidyut Nagar, Rampur, Jabalpur 482008

16.

Sh. Baleshwar Sharma CMD (MPMKVV Co. Bhopal), Madhya Pradesh State Electricity Board, Shakti Bhawan, Vidyut Nagar, Rampur, Jabalpur 482008

17.

Sh. S. P. S. Parihar CMD (MPMKVV Co. Indore), Madhya Pradesh State Electricity Board, Shakti Bhawan, Vidyut Nagar, Rampur, Jabalpur 482008

18.

Sh. Rajesh Aggarwal CEO, BSES Rajdhani Power Ltd, BSES Yamuna Power Ltd., BSES Bhawan, Nehru Place, New Delhi 110019

19.

Sh. R. C. Natrajan Head RCM, BSES Rajdhani Power Ltd, BSES Yamuna Power Ltd., BSES Bhawan, Nehru Place, New Delhi 110019

20.

Sh. K. U. Anjaria Chief Engineer, BEST Undertaking, P.O.Box No. 192, Best House, Mumbai 400039

21.

Sh. S. D. Ukkali Managing Director, Hubli Electricity Supply Company, Eureka Junction, 2nd Floor, T B Road, Hubli

22.

23.

Smt. V. Manjula Managing Director, Gulbarga Electricity Supply Company, Railway Station Area, Main Road, Gulbarga Sh. Gaurav Guptha Managing Director, Mangalore Electricity Supply Company, Maraoli, Mangalore

24.

Sh. P. B. Ramamurthy Managing Director, Bangalore Electricity Supply Company, Nrupatunga Road, Bangalore 560001

25.

Sh. N. Vijayabhaskar Managing Director, Vishweshwaraiah Vidyut Nigam Ltd., Kaveri Bhawan, K. G. Road, Bangalore 560009

26.

Sh. T. S. Sridhar Chairman, Tamil Nadu Electricity Board, N P K R R, Maaligai, Electricity Avenue, 800, Anna Salai, Chennai 600002

27.

Sh. T. M. Manoharan Chairman, Kerala State Electricity Board, VIIth Floor, Vidyuthi Bhavanam Pattom, Thiruvananthapuram 695004 (Kerala)

28.

Sh. P. Gopal Reddy Chairman & Managing Director, Northern Power Distribution Co. of AP Ltd., H No. 1-1-478 & 503, Chaitanyapuri, Opposite REC Petrol Bunk, Hanamkonda Warangal 506004

29.

Sh. K. Ranganatham Chairman & Managing Director, Southern Power Distribution Co. of AP Ltd., H No. 19-3-13 (M) Upstairs, Renugunta Road, Tirupati 517501

30.

Sh. Y. G. K. Murthy Chairman & Managing Director, Eastern Power Distribution Co. of AP Ltd., H No. 30-14-9, Near Saraswati Park, Daba Gardens, Visakhapatnam 530020

31.

Sh. Dinesh Kumar Chairman & Managing Director, Central Power Distribution Co. of AP Ltd, H No. 11-04-660, 3rd Floor, Singareni Bhawan, Adjacent to Hanuman Temple, Red Hills, Khairatabad, Hyderabad 500004 (AP)

32.

Sh. S. R. Sethi Director (Operation), Delhi Transco Ltd., Shakti Sadan, Kotla Road, New Delhi - 110002

33.

Sh. P. H. Rana Member (Tech.), Gujrat Energy Transmission Corpn. Ltd., Sardar Patel Vidyut Bhawan, Race Cource, Vadodara 390007

34.

Sh. Sudhir Shah Director, Ahmedabad Electricity Co. Ltd, Electricity House, 2nd Floor, Lal Darwaja, Ahmedabad 380001

35.

Sh. M. V. Krishna Rao Director, Global Energy Consulting Engineers, 12-2-823/A/25, Santosh Nagar, Mehdipatnam, Hyderabad 500038

44.

Sh. Praveen Kapoor Director, eMerge Software Pvt Ltd., 169, Ist Floor Raja Garden, New Delhi 110015

36.

Sh. Prakash Nayak Vice President, Utility Automation, ABB Ltd., Plot 5&6, Peenoy Industrial Area, Bangalore 560001

45.

Sh. Rakesh Sharma General Manager - Infrastructure, Spectramind eService Pvt. Ltd., 239, Okhla Industrial Estate, Phase - 3, New Delhi - 110020

37.

Sh. P. Neogi Chief Executive, Noida Power Co. Ltd., Commercial Complex, H- Block, Alpna 11 Sector, Greater Noida City 201308

46.

Sh. Kumud Goel Managing Director, KLG Systel Ltd., Electronic City, Gurgaon-122015

38.

Sh. I. A. Khan Dy. Advisor, Planning Commission, Yojana Bhawan, Sansad Marg, New Delhi-110001

39.

Sh. Vikas Kashyap General Manager, Secure Meters Ltd., 3rd Floor, Tower ‘A’, Millenium Plaza, Sector 27, Gurgaon-112201

40.

Sh. Ashish Tandon Regional Director (North), Alstom Ltd., 14th Floor, Pragati’s Devika Tower, 6, Nehru Place, New Delhi 110019

41.

Sh. S. Majumdar Executive Director, Power Grid Corporation of India Ltd., B-9 Institutional Area, Katwaria Sarai, New Delhi-110016

42.

Sh. A. K. Tripathy Chief T & D, Bharat Heavy Electricals Ltd., Integrated Office Complex, Lodhi Road, New Delhi-110003

43.

Sh. V. K. Shah Addl. General Manager (Projects APDP), Power Finance Corporation Ltd., Chandralok, 36 Janpath, New Delhi -110001

FOREWORD There are over 5 million circuit kilometers distribution lines and over 2 million distribution transformers with capacity of 142 million KVA, in India. Under rural electrification, more than 5,00,000 villages (86%) out of total 5,87,000 villages, have already been electrified. More than 13 million pump sets out of a potential of 19.5 million, have also been energized. There are 120 million consumers with electric power supply utilities of the country, of which about 89 million (74%) are in domestic and 13 million (11%) in commercial category. Small and medium Industries have about 2.5 million (2%) consumers, HV Industries over 50,000 consumers whereas Irrigation has 14 million (12%)consumers. The electricity consumption in domestic sector is about 21 %, industry 34% and agriculture 31% of total Electricity consumption. On an average, about 4 million new consumers and 1,50,000 new distribution transformers are added annually. Distribution Network plays the most crucial role in connecting Utility and the Consumers. Usually networks are designed to cater the peak demand efficiently. Obviously, the network has to be more efficient to the variation of load demand. It is estimated that 75% of total system losses occur at distribution level. Lengthy and overloaded primary feeders are conducive to heavy line losses and distress the supply conditions. Rural electrification system in India is characterized by high power losses, which are of the order of 30%. High peak demand caused by simultaneous operation of irrigation pumps is another serious problem. Nearly 75% of distribution transformers in rural area are exclusively to feed pump loads. Distribution automation is a system that enables an electric Utility to remotely monitor not only the system but also the ultimate aim of remote metering interrogation, co-ordinate cost effective distribution automation in a real time mode from remote location. The objective of overcoming power shortages by reducing peak load and consequent power loss reduction and controlling the theft of energy will in turn minimize the duration of outages, ultimately resulting in improved quality of service or power quality. The conference spread over two days, shall have following six technical sessions besides Inaugural Ceremony as opening session and Panel Discussions & Valedictory session : Distribution System Reforms

Distribution System Optimisation

Customer Services

Regulatory and Legal Issues

Organisational Structure

Distribution System Management

We are grateful to Shri K. Jothiramalingam, Chairman, CPU & Managing Director, Karnataka Power Corporation for his excellent support. We are grateful to eminent experts for Chairing the Sessions/ authors for their valuable presentations and sponsors, Karnataka Power Corporation, M/S Global Energy Consulting Engineering Pvt. Ltd & M/s Vijai Electricals Ltd. for sponsoring the conference as Co-Organizers & M/s. KLG Systel Ltd. & IEE as Co-sponsors of this conference. We are also thankful to Shri A. K. Sah, Chairman Apex Committee & Former Chairman & Managing Director, NTPC and Chairman Premier Mott MacDonald, Sh. A K Sardana, Chairman Organizer Committee & Chief Executive Officer, North Delhi Power Ltd. & Shri Mata Prasad, Chairman Technical Committee & Former Advisor, (Power Trans.) ABB, and Shri R. K. Narayan, Former CMD, PGCIL & Sr. Adviser NDPL for their valuable contribution.

C. V. J. Varma Secretary General, CPU April, 2004

Contents SESSION – 1 ..................................................................................................................................... 10 1. Distribution Reforms : The Way Forward .............................................................................................................. 11 2. Privatisation of power distribution system : A study of micro level issues in Andhra Pradesh ........................ 15 3. Benchmarking of the Electricity Distribution Companies in India ....................................................................... 26 SESSION – 2 ..................................................................................................................................... 34 1. Increasing Efficiency & Reducing Losses with Minimal Cost Investment for Distribution Utilities .................. 35 2. Distribution Network Optimization and Planning Studies .................................................................................... 40 3. Making Investments in AM/FM/GIS Solutions Pay for Electricity Utilities.......................................................... 46 4. Integrated Resource Planning and Supply Side Management in Power Systems ........................................... 51 5. Advance Methods to curb Voltage Instabilities in Distribution Network ............................................................. 59 6. Consumer Indexing, Network Information Management Systems, Asset Management ................................... 70 7. Prefabricated Distribution Substation .................................................................................................................... 77 8. Application of IT in Distribution Systems for Revenue Improvement ................................................................. 86 SESSION – 3 ..................................................................................................................................... 91 1. Remote operation of Bhiwadi S/S from Ballabhgarh S/S ..................................................................................... 92 2. Utility – Customer Interface Trouble Call Management/ Call Centers and Complaint redressal ................... 101 3. Data Communication Architecture using IEC 61850 Protocol for Substation Automation ............................. 113 4. Looking ahead at Power Distribution Business ................................................................................................... 122 5. Supervisory Control And Data Acquisition (SCADA) Laboratory for Research & Training in Distribution Automation ..................................................................................................................................... 127 6. Communication Infrastructure in CESC Ltd. for Automation of Distribution Management (Existing Practice & Emerging Prospects) ........................................................................................................... 137 7. Estimating Cost of Unreliability for Commercial Customers .............................................................................. 153 SESSION – 4 ................................................................................................................................... 156 1. Real Time Operation of Power Systems under ABT Mechanism : Some issues while implementing within State Grids .......................................................................................... 157 SESSION – 5 ................................................................................................................................... 163 1. Planning of Distribution System A Case study of Rural Electrification ................................................................................................................... 164 SESSION – 6 ................................................................................................................................... 171 1. Ensuring Network Reliability in a Competitive Market Framework : Trans Grid’s Approach .......................... 172 2. Demand Side Management : Need and Solutions .............................................................................................. 179 3. Impact of Electricity Act 2003 on lignite fired boilers in Neyveli Lignite Corporation ...................................... 187 4. Realtime Distribution Management for Urban Systems ..................................................................................... 191 5. Brief Overview of Southern California Edison Power System in United States of America ........................... 205 6. Distribution Management – Metering, Billing & Revenue Realisation .............................................................. 211 7. On-line Fault Detection Algorithm for Three Phase Radial Distribution Networks .......................................... 218 Panel Discussions & Valedictory Address ................................................................................ 222 1. Convergence of Power and Telecommunication ................................................................................................. 223

SESSION – 1 Distribution System Reforms • “Impact of Electricity Act 2003 on Power Supply Industry” • “Benchmarking for Reliability, Quality of Services, Upgradation and Cost” • “Lessons of Corporatisation and Privatisation – Gains and Pains”

Chairman : Shri H. W. Bhatnagar, CMD, Bharat Heavy Electricals Ltd.

Key Note Speakers : i)

Sh. Ajay Shankar, Joint Secretary, MOP, Govt. of India & Chairman, DVC “Impact of Electricity Act 2003 on Power Supply Industry”

ii)*

Sh. K. Ramanathan, Former Member CEA & Distinguish Fallow, TERI “Distribution Reforms”

iii)

Sh. J. P. Chalasani Director (Business Development), Reliance Energy Ltd. “Lessons of Corporatisation and Privatisation – Gains and Pains”

iv)

Sh. Dinesh Kumar, CMD, Andhra Pradesh Central Power Distribution Company Limited “Lessons of Corporatisation and Privatisation – Gains and Pains”

v)*

Dr. S. Malikharjun Rao “Privatisation of power distribution system : A study of micro level issues in Andhra Pradesh”

Additional Papers included in Binders : 1.* “Benchmarking of the Electricity Distribution Companies in India” by Dr. Prem Kumar Kalra, Sh. Vipin Prakash Singh, Sh. Yogesh K. Bichpuriya, IIT Kanpur

* Papers received by the time of compilation

Distribution Reforms : The Way Forward

K. Ramanathan Distinguished Fellow, TERI

Outline of Presentation • • •

Reform initiatives in recent years focussed on the distribution segment Overview of performance: Loss reduction,metering, quality of supply & service Way forward: Focus areas

Reform Initiatives APDRP : 100% metering, energy audit, better HT/LT ratio, replacement of DTs, IT solutions, etc. • Development of Centres of Excellence Electricity Act 2003 : Reorganisation of SEBs, mandatory metering, provision for OA, trading, decentralised generation, special focus on rural electrification, consumer protection, efficiency improvements and tariff rationalisation through regulatory interventions, etc. • A robust legal framework to proceed with

Reform Initiatives Energy Conservation Act : Focus on supply side and demand side efficiency improvements • A high value legislation REST Mission : Electrification of 10 m households through decentralised distributed generation Systems • Focus on rural electrification Other initiatives : Anti-theft legislations, Reliability level monitoring (mandated by ERCs, utility level initiatives, CEA level monitoring), DRUM (USAID partnership initiative), etc.

Performance Overview Losses

Source: MoP

11

• •

More realistic assessment of losses; but no significant improvement in most States Variation in data from different sources!

Performance Overview ARR – ACS Gap

Source: MOP

• •

Gaps still high; increase in few States in last 2 years Variation in data from different sources!

Performance Overview Metering Some improvements in 11 kV feeder and consumer level metering

Source: MoP

Variation in data from different sources!

12

Performance Overview Quality of supply & service 120

100

80

P re -A B T 2002

60

Post ABT 2003

40

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Improved frequency profile (post ABT) Better voltage profiles & reliability in some areas • Marginal improvements in service • Few sample studies; lack of utility-wide reliable data • Increase in consumer awareness

Areas to focus : Some suggestions Focus Areas

• • • •

Increasing access and availability Restructuring strategy Harnessing CPP Distributed generation Institutional and financing mechanisms

• • •

Government and HRD Professional management Administrative and financial autonomy MIS

• • •

Quality of supply and service Regulations on standards of performance, consumer rights, complaints handling, etc. Monitoring and enforcement strategy Involvement of NGOs, consumer forums

• • •

Metering, billing and collection Advances in metering technologies Improved billing and collection procedures Franchising/ private sector participation

• • • •

Energy efficiency comprehensive energy audits special focus on anti-theft measures energy conservation and DSM ESCO initiatives

13

• • •

Data base Quality of data GIS mapping Computerisation

• • •

System planning & operation Load research Long-term master plan SCADA

• • •

Regulation Minimising regulatory risks Promoting consumer empowerment Financial viability of utility

End note … Unless the distribution segment of the industry is efficient and solvent any solution to the problems of the power supply industry will be inadequate and incomplete.

14

Privatisation of power distribution system : A study of micro level issues in Andhra Pradesh

Dr. S. MALLIKHARJUNA RAO

Introduction It is now over a decade since reforms in power sector were initiated in India. Government of India recognised the fact that there is a growing demand for power due to growth in economic development and quality of living. However as the public sector can not meet the demand by increasing the generating capacity due to severe financial constraints, GOI opened the power sector to private investors. The central government offered several concessions to woe the investors into power sector. However the private investment in power sector has been very insignificant. It was hoped that privatising the power sector would bring competition and competition would improve efficiency, in the functioning of utilities. Consequently the consumers would have quality power at competitive tariffs with promptness and reliability in service. This paper is divided into two parts. Part A deals with the initiatives taken by the Andhra Pradesh state government in privatization of distribution system in the state and identifies main reasons for not achieving the same in the last 3 years. Part B identifies the prerequisites for privatization of distribution system and study the performance of one of the distribution companies, Central Power Distribution Company of AP Limited (CPDCL) since its formation in the year 2000. The micro-level issues of distribution system are analysed. Finally the findings and conclusions of the study are presented.

Part-A The central government came out with a new Electricity Act in 2003, which made not only generation but also transmission and distribution activities open to private investors. This initiative has been well received by the experts and investors. The government also took initiative to accelerate the reforms in power utilities for improving the performance in distribution system. Toward this end the government launched a programme popularly known as Accelerated Power Development and Reform Programme (APDRP) in February 2000. The government through this programme encourages the states to pursue reforms by providing easy loans, grants and incentives. The main purpose of this programme is to address the issue at the micro level (consumer, feeder, and substation) to the macro level (circle, state, national) covering intervention at six stages. As the government is pursuing the programme with commitment, positive results are witnessed in the distribution system. Andhra Pradesh is fore runner in implementing the reforms in power sector. The state electricity board was restructured in February 1999 into generating and transmitting companies known as AP GENCO and AP TRANSCO. Andhra Pradesh Electricity Regulatory Commission was set up in February 1999. Thus the power sector in A P which was hither to controlled by the state government is now being regulated by independent authority. AP TRANSCO was further restructured in March 2000 by converting into a holding company and separating distribution activity, by forming four The author acknowledges the assistance received in conducting this study, from University Grants Commission under the scheme “University Potential with Excellence” implemented by the University of Hyderabad, India. 15

distribution companies, as its subsidiaries. Although distribution companies are responsible directly for distribution system in the state, AP Transco has also been taking initiatives, which will enable all the subsidiaries improve their performance and also tackle the transitional issues. The performance of AP TRANSCO over the past three years earned best rating from rating agencies. AP was given the highest score of 73 among the 12 states assessed by Crisil. Crisil’ top rating of the state recently after the Union ministry of power sought an assessment of performance of various states, has vindicated the credibility of reforms in AP. “The availability of data was good with respect to Andhra Pradesh and that the staffs in the state’s power utilities were responsive in sharing the information, which was again the best among all the states. The rating recognised the effective implementation of anti-power theft Bill and the legislative steps taken through the Reforms Act and the AP (amendment) 2000 to the Indian Electricity Act. The rating of the sector was also high with reference to the number of employees per 1000 consumers”. (04-11-02, The Times of India). In conformity with the terms and conditions attached to the sanction of loan from World Bank, Government of A P attempted to privatise the distribution system. However the programme has not been successful till now for various reasons. State government has faced problems in implementing the reforms in the distribution system. In the first stage attempt was made to sell the distribution companies based on Orissa model. They have called for tenders, but it didn’t get the proper response. With small changes to Orissa model, Delhi government has tried to sell the DISCOMs; AP government has tried in the same way, but again failed to attract the private companies. According to the new Electricity Act, anywhere, anybody can get the distribution license. There is no exclusivity in power supply. As a result the private agencies were hesitating to participate in the privatisation of distribution system, as they would not get exclusive rights for power distribution in specified areas. When it was realised that out right sale of DISCOMs would be difficult, there was another proposal to privatise the activities of sub-stations. By this approach, it was thought that the thefts, unauthorised connections of power and old dues would get resolved and increase the revenue. CPDCL went a step ahead of other DISCOMs and decided to privatise all the activities of all substations under its control. The other DISCOMs wanted to award the substations on a single specified amount or fixed contract, by estimating the revenue per unit and requesting the interested parties to quote one rate. Under this approach the successful bidder will have to mange all the activities themselves. Since the contractors did not have proper understanding of this approach, the rates quoted by them were either below or above the estimated rate with large variations. Actually, maintenance of substations and repairs of transformers are already contracted out. With a view to contract out all the activities under the aegis of ‘Electricity Community facilitation Center’ such as maintenance of lines and substations, transformers and fuse off calls, replacement of defective towers and commercial activities such as billing, collections and reduction of thefts will be taken care of by the contractor. Although this approach is ideal, since the condition of each substation is different, the contractors did not take any risk in quoting the bids. Even the DISCOMs were not sure as to how to handle this new approach of franchising. Some DISCOMs have franchised the substations to NGOs and Farmers Societies with some concessions. The scheme of franchising is carried out in AP with many apprehensions. CPDCL is rethinking about the privatisation of nine 33 K.V. sub-stations. The company invited tenders for privatisation of these substations. The main responsibilities of the contractor would be: (i) raising bills on customers as per spot billing approach. ( ii) collection of bills from the customers (iii) when power supply is interrupted , restoring the supply of power, by arranging their own fuse off call vehicles (iv) maintenance of substations, transformers and lines and (v) providing new connections on the sanction of operation division. Along with the privatisation of 11 substations, it was also decided to privatise the technical activities in 27 subdivisions. While the process of privatisation at the micro level is on, some interesting developments took place in the company.

16

i) ii) iii) iv)

The losses in Hyderabad City have been reduced from 44% to 15% (11 K.V.) Revenue is increasing. In 2001 April the total income was Rs.80 cores, it has risen to Rs.100 crores. On average revenue on every unit has been increased from Rs. 2.59 to Rs.3.32. Power engineers and Employees Unions are against the privatisation. There was a strong feeling that when the company has been reducing losses of the company by improved performance, why it should allow private contractors enjoy the fruits.

Hence the privatisation process of distribution was put on hold. World Bank has decided to study the power reforms in Andhra Pradesh before extending the next trench of its structural adjustment loan (SAL). The state request for a SAL of Rs.1, 830 crore is pending with the World Bank for the past one year. The government was anticipating that the loan would be released during the current fiscal and has accordingly prepared the budget estimates for 2003-04. Bank officials were reportedly unhappy with the slow pace of reforms in the power sector. Some of the conditions attached to the loan were : i) ii) iii) iv) v)

Transco need to increase its revenue by 15% per year. The World Bank has extended Rs. 870 crore for power sector reforms. to cut the subsidies for agricultural and turn power utility companies into profitable ventures To reduce the difference between producing costs and selling costs of power, also known as “cost to serve”; Power should be sold only through metering; and Privatise the distribution system.

But state government couldn’t meet all the conditions due to political and socio- economic reasons. The government however provided a Rs.1, 509 crores subsidy to Transco this year, though marginally reducing the outlay by Rs.42 crores over the previous year. It has also promised not to increase tariff for domestic and agricultural consumers till next year, and reduced tariff for high- tension consumers. The energy department explained the results achieved from past few years to the World Bank team. They are as follows. 1) T&D losses have been reduced from 38% to 26% 2) Considerable improvements in voltage levels 3) Hundred per cent collection of power dues 4) Government subsidies have been reduced to half the amount. 5) Rationalisation of power tariff for industries by reducing the charges 6) Ahead of others in implementing the power sector reforms.

Part B Even if it were conceded that the state could have successfully sold the DISCOMS, the programme of privatisation would not be successful over night. The private companies, which buy the DISCOMs, still look for support during the period of transition. The following issues require to be handled carefully for lending credibility to the privatisation programme. i)

ii)

iii) iv)

Role of the state government for support in anti-theft legislation and enforcement thereof and assistance for sometime to contain the tariff for agriculture and domestic consumers, who may not afford power in ‘no-subsidy’ environment. Role of the Regulator in balancing different dimensions while fixing the tariff from the perspective of sustainable long term development of power sector and as a facilitator for fixing performance standards in various activities of power sector. Attitudinal change of employees for improving the performance Legacies of earlier system such as losses in distribution, culture of the consumers in cooperating with the system manager in metering, billing, and collection of dues.

17

It is hypothesized that the environment will be same during the period of transition whether the operator is from private sector or public utility. In this context, the Central Power Distribution Company of Andhra Pradesh Limited (APCPDCL) is selected as a sample for in depth study of managing the distribution in independent regulatory environment over the last three years with specific reference to the above issues. The CPDCL was incorporated on 30th march 2000 as a subsidiary of the holding company AP TRANSCO, and started its operation from 01-04-2000. It had completed three and half yeas of it operations in Distribution and Retail supply of power, fulfilling the needs of around 5 million electricity consumers spread over 85750 sq. km. of seven districts of Anantapur, Kurnool, Mahaboobnagar, Medak, Ranga Reddy and Hyderabad. Though the company started its operation on 1-4-2000, the APERC (Regulatory commission) granted license for Distribution and Retail supply of power from 01-04-2001.

Initiatives take up by CPDCL a)

To improve the efficiency in metering, billing and collection :

1)

3)

Electronic spot billing : Bills are issued on the spot, which help reduce errors in meter reading by spot validation, decrease revenue cycle time and thus reduce the credit period, and also considerable reduction in consumer complaints on wrong billing and other billing disputes. Payment facilities : For convenience of consumers to pay the bill the following facilities are made available - Payments through or regular electricity Revenue Office (ERO), e-seva centers for bill payment and pay any where, payments through banks with the help of certain agencies like bill junction and bill desk, online payment through Citibank from web site www.apcentralpower.com. Separate HT cells in all operation circles to promptly address grievances of HT consumers.

b)

Investment in new technology to improve & monitor power supply position :

1)

The Supervisory Control and Data Acquisition System (SCADA) network covering the Hyderabad and the neighboring ten municipalities of Ranga Reddy District, controls and monitors the distribution system at 33 KV and 11KV levels. This is a step ahead in improving the efficiency of distribution system. A twenty-seat call center with a four digit (1912) phone no. at the SCADA center is enabling the Company to attend to the complaints of the customers without delay. Established round the clock Call centers with four-digit number (1912) in all the Circle/District Headquarters enabling consumers to complain on outage of supply. 330 Nos. Industrial feeders in CPDCL separated to provide reliable supply (In FY 2003 identified 64 No.s 11 KV feeders and completed 45 No.s) Monitoring of power supply to Industrial feeders and Industrial estates being done by senior level officials. (DE / Operations & ADE / Operation) Established Control rooms in all the Circles/District head quarters for Monitoring of interruptions and breakdowns on 24 hourly basis and to take appropriate action Monitoring of Reliability indicators like SAIFI, SAIDI & CAIDID on 11 KV feeders in Hyderabad and 34 Towns in CPDCL Substation wise meeting with Farmers to resolve power supply related issues Conversion of 25 No.s 11 KV feeders to HVDS in Hyderabad which are having high losses and prone to theft. Conversions of 63 No.s 11 KV feeders to HVDS in rural districts by providing small capacity three phase and single phase DTRs Providing 24 hours of single-phase supply on rural feeders. (Identified 1480 predominantly Agricultural feeders and completed 1128)

2)

2) 3) 4) 5) 6) 7) 8) 9) 10)

18

11) 12)

13)

c)

Laying of AB cable in theft prone areas to arrest directly tapping from the bare wires (Identified 1657 villages and completed 1108) Intensive inspections carried out to arrest illegal abstraction of Energy (2.32 lakhs service inspected and booked theft cases 12300 and malpractice cases 1638 the amount assessed Rs 978 lakhs and prosecuted 29992.) Introduction of Under Ground cabling for improving safety, aesthetics and uninterrupted quality power supply to the consumers in Hyderabad. Efficiency improvement measures

CPDCL undertook the following measures to improve efficiency : 1) 2) 3) 4)

Stringent measures have been taken to control theft energy under the provision of the A.P. Amendment Act 2000 to the Indian Electricity Act, 1910. Old meters are being replaced with high quality meters to reduce metering losses. HVDS is implemented to improve the voltage profile and overall supply conditions. A large number of capacitors have been installed at the Sub-stations and the lines to reduce the reactive loading in the lines for loss reduction as well as for improvement of the voltage.

Substantial reduction in losses has been achieved as observed from the following details.

Input Total sales Losses % Losses

2000-01 16434 11163 5271 32.07%

2001-02 16686 12179 4507 27.01%

2002-03 17248 13257 3991 23.14%

All the above measures along with the tariff rationalization by the AP electricity regulatory Commission have resulted in the improvement of metered sales and improvement of revenues so the companies. d)

Improvement in customer service The following steps have been taken by CPDCL to improve service to customers :

i) ii)

iii)

iv)

v)

vi)

Spot billing has been introduced in the entire jurisdiction so as to improve the billing efficiency. Mobile Break down Vans have been introduced to attend the Fuse Off Calls through regular communication between the FOCs and Mobile vans thus improving the efficiency in attending to the consumer complaints. The reserve stock of distribution transformers are now maintained in sufficient quantity at subdivision office. This has drastically reduced the time of replacement of failed distribution transformers and increased the number of hours of availability of supply of power to the consumers especially in rural areas. Customer service centers have been opened in the twin cities and also at all the district head quarters for attending the consumer complaints as per Citizens Charter. These centers pursue till the complaints are attended. CPDCL has brought out a Citizens Charter, wherein standards of performance to be maintained in attending to fuse off calls, rectification of street lights, line break downs, replacement of failed distribution transformers, attending to complaints on quality of power supply etc. Vidyut Adalats are conducted on monthly basis at all 308 Mandals in the company to resolve and rectify issues relating to wrong billing and other commercial complaints

19

e)

Financial performance The financial performance of the company is as follows: (Rs. In crores) 2002-03 3298.75 506.19 255.89 3494.76 105.99 128.22 13.61 855.44

Revenue from sale of power Revenue from subsidies and grants Other income Power purchase cost Provision for depreciation Interest and finance charges Surplus Net worth of the company

2001-2002 2428.30 1060.23 64.50 3190.37 92.89 83.48 (126.13) 747.30

The revenues of the company have increases by 35. 84% in 2002-03. CPDCL was able to reduce the losses through improvements in metering and reduction of technical and commercial losses. f) Infrastructure Laying of underground cable and coming up with new substations for Hyderabad city with an amount of Rs. 290 crores funded by Power Finance Corporation. The company took up the efficiency improvement measures in right earnest under the directions of the Govt. of Andhra Pradesh and the APERC with substantial success in fist 3years of its formation. Electricity infrastructure : Sl.No. 1. 2. 3. 4. 5. 6.

Particulars 33 KV lines (CKM) 11KV lines (CKM) LT lines (CKM) 33/11 KV Sub-stations Power Transformers Distribution Transformers

As on 31-03-01 11045 67833 143587 714 997 69913

As on 31-03-02 11117 69066 145110 746 1030 77110

As on31-03-03 11607 70892 147413 816 1116 85507

The CPDCL has taken up substantial improvements works to strengthen the existing distribution networks so as to improve quality of the supply to the consumers and also to meet the increasing demand for new connections. From the above discussion it is clear that the company has been improving its performance to satisfy the customers despite the hurdles in the process. Micro level issues Role of the state government during transitional period Ever since the power sector reforms programme was undertaken in Andhra Pradesh the government has been playing active role for its success. i) It has established the Regulatory commission for regulating the power sector. ii) It has restructured the erstwhile state electricity board in to corporations in 1999 to improve 20

iii) iv) v) vi) vii)

efficiency and be accountable for performance. To help the distribution companies face the transitional phase, subsidies were allowed for agricultural and domestic sector Review of performance of the utilities to improve performance so that the benefits can be felt in lower tariff and improved customer satisfaction Supporting the utilities in obtaining loans from national and international agencies for investment in infrastructure and technology which reduce losses in the power sector. Supporting the utilities in reducing theft of power by enacting anti theft legislation and enforcement thereof. Be firm in recovery of old dues from consumers including government departments and public undertakings; power was disconnected to the Water Board which has defaulted to the tune of Rs. 47 crores to press for settlement of old dues.

Chief minister Mr. Chandrababu Nayudu through his leadership has provided necessary environment for development of power sector on healthy lines in Andhra Pradesh.

Role of Regulatory Commission The Regulatory commission has to balance the interests of different stakeholders while discharging its functions. “Of the various functions of the Commission, fixation of tariff for bulk and retail supply of power was an important function of the Commission. While fixing tariff, the Commission was required to keep in view both the interest of the consumer as well as the consideration that supply and distribution could not be maintained unless the charges for the electricity supplied were adequately levied and duly collected.” However, Regulatory commission is facing criticisms, from Opposition parties, like it is taking decisions in favour of private projects and policies of the government but not in favour of consumers. Secretary of the state wing of CPM leveled serious charges against the commission “ ERC does not listen to whatever is mentioned from the peoples point of view. It gives an impression that ERC is carrying out exercises only for Private projects. It is not functioning as per the expectations of people.” ERC is hesitating to review the power purchase agreements, which are influencing the tariffs. Government is thinking that privatisation is panacea for all problems. “It is unfortunate that the decisions are taken without examining the perspective of poor man.” (10-03-03, Eenadu). To dispel the misgivings about its role, the Commission directed Transmission Corporation of AP limited to initiate negotiations with generating companies in order to ensure cost reduction as per the existing power purchase agreements (PPAs). The commission said that it would not be able to reopen the PPAs until a case pending in the courts on the subject is settled. In the meanwhile it directed Transco to explore areas for cost reduction within the existing PPAs and submit a report to the APERC by 30th June 2003. In another significant directive, the commission directed Transco not to cut the power during periods of shortage to industries and also said the Transco and the power distribution companies should not obtain load relief from sub-stations, which have more than 50% of load from industries. With respect to collections of arrears from consumers, the commission directed that the DISCOM must separately indicate on consumers’ bills the opening balance as on April, 1, 2003, The arrears which accrue from that date till the date of the bill and current consumption charges pertaining to the bill. These directives, among others, were contained in the detailed tariff order of the APERC. (09-04-2003, The Hindu). Thus the commission summed up the priorities to be attended to, for fulfilling its role, “the immediate tasks before the Commission was to improve the operational efficiency of the sector, reduce technical & commercial losses and the scale of cross-subsidization to the minimum by ensuring that within a category of consumers, the total cost of supply to the category was recovered which would help efficient use of power, introduce metering in the agriculture sector, levy tariff or raise tariff for supply of power to Farm sector, meet situations arising out of non-payment of subsidies assured by the Government while subsidizing supply of power to Farm and Domestic sectors and for this reason reduce the dependence on external subsidy, move towards Compensatory tariffs, improve the financial viability and credibility 21

of the utility to attract power developers and finally reduce the cost of supply”. The commission has matured in functioning and several and-mark judgements during the past 3 years. Cooperation of consumers required for improving the quality of power According to AP Transco managing director Rechal Chatterjee, there are possibilities to produce quality power supply without increasing the power tariffs. She opined that there was a need for peoples’ co-operation and participation for improving the quality in power and winning the confidence of the consumers. Increased consumers’ participation and co-operation will lead to reduce the cases of power theft and the other problems. There is a need to bring awareness of results of successful performance of the power utilities among the consumers. She says “per capita consumption of electricity has increased from 364 units to 510 units. Losses in distribution sector are reduced from 38% to 26%. Interruptions in power supply have been reduced to 21%. Failures in transformers has come down from 21.4% to 17.66%.” (21-04-2003, Eenadu) AP Transco introduces TIMS to reduce transformer failure The Transmission Corporation of Andhra Pradesh has introduced its transformer information management system (TIMS) to help reduce failure of distribution transformers. The software, developed in-house, has been introduced on a pilot basis as southern power distribution (SPDCL). AP Transco CMD Rechal Chatterjee said that pilot scale of TIMS had yielded substantial results and the system was being rolled out to other DISCOMS. TIMS has been developed as a technology solution to manage the distribution transformers system, which enables effective tracking of transformers through their entire life-cycle. Mistakes in spot billing Spot billing has been introduced in some areas of Hyderabad in July 2001, to reduce the mistakes in electricity billing. This was extended to all other areas of the city in phased manner. But even in the spot billing, many mistakes are found out. Sometimes it is happening because of the failures in hand-held computers. Consumers are facing problems because of these mistakes in billing. The officials are making the consumers to run around the revenue offices for correction of the bills. The bills are getting corrected after lot of struggle suffered by the consumers. Meanwhile, the staff are warning the consumers for disconnection of power for not paying the bills. In vidyut adalats majority of complaints are on mistakes in billing. In the city vidyut adalats are held in the office of Assistant Divisional Engineer (subdivision) every Saturday between 4PM to 6PM. 74 adalats were held between 3rd week of May and end of June. There are 27 subdivisions in the city. Out of 801 complaints during this period, 780 were solved . out of 801 complaints , 342 relate to wrong billing, mistakes in meter reading account for 242, complaints on voltage problem 21, non working of meters 37. The service connections in the city are about 16 lakhs. Compared to this, the number of complaints are insignificant. In the old city about 2.5 lakhs of new high quality meters were fixed. Therefore there are no complaints from this place. The customers are very unhappy for the delay shown by the staff for correcting mistakes. But again and again the mistakes are happening. The complaints are increasing about mistakes in billing in the “vidyut adalats”. Billing for half of the connections were done by CPDCL staff and for the other half were attended by the staff of private accounting agency. While one staff member of the private agency is billing for about 100 to 150 connections per day, it requires two members of CPDCL raise bills for only half of what the private agency does. The staff of private accounting agency are using less number of hand held computers. Quality is an issue To reduce the business losses, power distributions companies are buying meters in a large quantity. The four distribution companies in AP placed orders for supply of 20 lakhs of meters. Companies from China, Korea also competed to get the orders. The quality of meters supplied are found to be 22

defective in large scale. As there was criticism from the public about the deal, the CPDCL tested the quality of sample of meters. In a lot of 5000 meters a sample of 153 meters were tested and found 80 meters were defective. Results of testing of meters of other lots showed similar results. For 3 phase meters some companies quoted below Rs. 1500 and some quoted above Rs. 4000. Similarly for single phase meters some companies quoted around Rs. 500 and some companies quoted around Rs.900. CPDCL placed orders with suppliers who quoted the lowest price, to avoid public criticism. The CPDCL carried out four stage testing of meters. In the first stage the company tests the sample before accepting the tender. Thereafter tests are conducted by DGSD, RITES, and Central Power Research Institute. Even after fixing , if the meters are found to be defective these are returned back to the supplier. In spite of all these procedures thousands of meters are found to be defective. If no such tests are conducted the quality of supplies is a big question. The consequential losses will be much larger. The CPDCL has since decided to entrust the purchases to DGSD. Lack of commercial approach Transco is spending a lot of money, to reduce the T&D losses without increasing charges for consumers. But the results are not satisfactory. To reduce the T&D losses by 0.5%, Transco is planning to spend Rs.561 core in the year 2003-2004. In other words for reducing losses by one per cent, Transco requires Rs. 1122 crores, in order to save Rs.78 crore. TRANSCO is taking loans to meet this expenditure, which should be repaid in next 10years. Including the interest, Transco has to repay the loan installment of Rs. 224 crore per year to save RS. 78 crore per year. Transco claims that, because of these investments, transmission system augmented its capacity for supply of additional 160 Million Units of power per day. However the transmission standards and voltage levels have remained as they were. (20-03-03, Eenadu) Vigilance Cell plans to solve the problem of power theft There are many cases pending on power theft, which are not solved yet. Vigilance cell in CPDCL is trying to find the solutions for these power theft cases. It was found that nearly 1, 20,000 cases are pending in 7districts. More than 30000 cases are pending only in 3 circles of Hyderabad. Vigilance officials decided to solve the power theft cases immediately, otherwise the number of cases will increase. They have planned to collect compounding fees from the people who are involved in the power theft for the first time. People involved in power theft more than once will have to face the imprisonment. An amount of Rs.1.20 crore is colleted per month by solving power theft cases, which were pending. Even many people are going to prison. 33 persons went to prison in Ranga Reddy district in June 2003, alone. However the cases are piling up. It is taking long time to arrest the offenders after the cases were booked. The main reason for the slow process is shortage of personnel. For each circle one inspector, one sub-inspector and four constables are allotted. They have to attend court cases and accompany the engineers for raids. Expediting arrest of offenders after registering the cases will have deterrent effect on power theft. This is a good approach to reduce the losses due to power theft. Laying of underground cables The central power distribution company of AP limited (CPDCL) is all set to make Hyderabad a ‘wireless city’ by replacing the overhead power cables with an underground cable network. As per plans, The Rs. 1,000 crore project is expected to be completed within three years. The power finance corporation (PFC) has already sanctioned a loan of Rs.289.7 crores for the first phase of the project. CPDCL managing director Dinesh kumar said that the company is planning to replace 1,600 km of 11 KV lines and 2,400 km of low-tension cables in the city. Distributions losses, which currently stand at 25%, will come down drastically, once the project is completed. Power theft by directly hooking from the electrical lines will also be eliminated. As a part of project, the company will erect several sub-stations across the city to maintain the quality of power supply (31-08-03, 23

The Times of India). However the current scenario is not encouraging. The scheduled arrangements for laying underground cable lines are stuck because the Municipal Corporation of Hyderabad is not according permission to dig the roads for laying cables. With the financial support of World Bank, plans have been made to lay 150 KM long 11 K.V. underground cable lines. Rs10. crore has been allocated to this project (28-08-03, Eenadu). Speed money is still playing a role in power sector All the contractors and workers are making money with out doing any significant work. But there are no subsidies in fixed charges, which have to be paid to the officials. Some recent statistics are showing the illegal acts of the officials in this sector. Recently Rs.3000 crore was spent on lines and substations. In that Rs.2000 crores worth of transformers tower bolts, conductors, breakers, insulators, other hardware tools were supplied by TRANSCO. The balance of money should be spent in civil works. Some statistics shows that at least RS. 120 crores had gone into the pockets of officials. Because of these illegal earnings, quality of supply is coming down, and nobody is bothered about it. (26-07-03, Eenadu)

Findings and conclusions (a) Findings 1.

The programme of privatisation of distribution system in andhra Pradesh has not been successful. The main reason being the apprehension about the provision ‘open access system’ in the new Electricity Act.

2.

The Central Power distribution company of AP Limited (CPDCL) has been improving its performance on several parameters.

3.

The government of Andhra Pradesh has been providing the enabling environment to the power utilities to improve their performance to the consumers.

4.

Regulatory commission has matured in its functioning and balancing the interests of different stakeholders and contributing to the development of power sector in the state.

5.

AP Transco is supporting the distribution companies by providing technology and administrative support.

6.

It is now recognised that the cooperation and participation of the consumers is necessary for improving quality of power.

7.

In the initial stages of spot billing several complaints were received about mistakes in billing and attracted criticism from consumers.

8.

Productivity of employees of CPDCL is low compared to that of private agency engaged in billing activity.

9.

Quality assurance is still a matter of concern in spite of systems are in place.

10.

Some of the decisions / actions show lack of commercial approach.

11.

It is prudent to deploy more workforce in critical areas such as vigilance on power theft where the company is yielding good results.

24

12.

The project implementation of laying of underground cable is slowed down due to delays in obtaining permission from MCH.

13.

The biggest stigma of public institutions “speed money” still daunts the company.

(b)

Conclusions

1.

he state government has been supporting the reforms in power sector by creating an enabling environment wherein an enterprise can perform at its best.

2.

The Regulatory Commission has been doing a balancing act for achieving a sustainable long-term development of power sector.

3.

The CPDCL has been improving its performance on several parameters in independent regulatory environment.

4.

The CPDCL has to work in future like a true enterprise if it wants to compete in an open system.

5.

The company has to provide better Value for Money to the customers in all its endeavors.

6.

It has to develop skills in managing the risk in all spheres of the organisation. The hallmark of professionalism lies in managing the uncertainty.

7.

The future enterprise relies on flexible model for resource optimisation and improving the return on investment.

References : 1.

Against the Current : Organisational Restructuring of State Electricity Boards 2003 (ED). Joel Ruet – Manohar Publishers, New Delhi, India.

2.

www.ercap.org

3.

Newspaper clippings.

4.

Power Line, March 2004

25

Benchmarking of the Electricity Distribution Companies in India Dr. P. K. Kalra +

Vipin Prakash Singh+ +

Yogesh K. Bichpuriya+

Indian Institute of Technology, Kanpur, India

ABSTRACT : As the pace of change accelerates in the 21st Century as a result of technological opportunities, liberalization of world markets, demands for innovation, quality and speed, organizations have to readjust and re-align their operations to counter all these challenges. The pace of change has increasingly forced organizations to be more outward looking, market oriented and knowledge driven. A useful tool that can help businesses build strong capabilities, ensure an inward flow of ideas and establish true competitive gaps is benchmarking. Deregulation and the privatization of electric companies are taking place at a rapid pace in India. With a large number of distribution companies coming into picture, there is a need for assessing their comparative efficiency to promote competition. This paper proposes a methodology, for the efficiency benchmarking of the distribution companies for a typical Indian system. Keywords: Benchmarking, efficiency measurement, distribution companies.

1.

INTRODUCTION

Deregulation and privatization of the electricity industry in India is currently at a rapid pace. The power sector in India faced major problems like: (a) breaks in the payment chain, leading to multiple inefficiencies in supply chain; (b) tariffs not coordinated according to the consumer, (c) blackouts, (d) power quality etc. It was recognized that meaningful reforms will not take place unless more distribution areas are privatized. This has been encouraged by the Electricity Act, 2003 passed by the Indian government. According to the Electricity Act, 2003, [1] it is mandatory for states to set up electricity regulatory commissions. Apart from making power trading a distinct activity, the Act seeks to allow open access to transmission and distribution systems and rationalization of tariffs. This restructuring typically involves moving from integrated, monopoly utility structure to competitive industry structure and shift from government / public owned utilities to private utilities. The purpose of the Electricity Act, 2003, is to create a competitive market for electricity distribution. Distribution is now seen as a three-element business: i) ii) iii)

Network business — ownership and maintenance of the network. Power market business — supplying power to consumers, either from your own source or from a third party. Services business — monitoring, billing, collections, etc.

With the increase in number of private companies, participating in the electricity distribution, there is a need to understand the Indian electricity network and then to develop a methodology which can judge the operational efficiencies of the distribution companises. Thus there is a need for benchmarking the distribution companies [2].

What is benchmarking ? “Benchmarking is a collaborative learning process among a group of companies to focus on specific operating practices, compare measures and results and identify improved processes within their organizations”. In case of power sector Benchmarking is done amongst the distribution companies, 26

who do similar things, but have developed their approach in a whole different way. The determination of benchmarks allows one to make a direct comparison. Any identified gaps are improvement areas.

2.

PRODUCTION PROCESS

Electricity distributors use their network and transformer capacity, together with labor inputs, to deliver a number of electrical units to a specified set of consumers and to meet a level of peak demand. At present, practical implementation of efficiency benchmarking of the distribution companies is carried out in few countries such as in USA and the Netherlands [3-4]. Normally the variables chosen as input and output for evaluating the efficiency of electricity distribution companies in England and Wales, Sweden, the US, New Zealand, is shown in Fig.1.

Fig. 1 Electricity distribution production process The experienced gained by these countries cannot be exploited in India as such because the parameters on which the efficiency calculations [5-6] are based are different in each country. One typical feature of the Indian electricity market is that the distribution companies vary greatly from each other in terms of size and operational environment, for example the length of the distribution networks as shown in Fig. 2. Therefore, an independent strategy for efficiency benchmarking of the Indian distribution companies is essential. To model the relative efficiency of distributors, no matter what type of services they maproduce, it is necessary to first define a production representative of the industry being examined. Distributors consider a wide range of inputs and outputs to provide services to consumers. The choice of inputs and outputs used for benchmarking the distribution companies varies from place to place and largely depends upon, management practices, operating environment etc. Similarly, the nature of services provided by distributors varies according the nature of consumer demands. Thus the proposed benchmarking methodology is capable of modeling the interaction between multiple inputs and outputs for efficiency evaluation which is well suited for the Indian system. Thus the variables chosen as inputs and outputs for the proposed model as shown in Table 1 varies that from the other tested model of different countries as shown in Table 2

27

Table

1 : The Proposed Production Process Model

Table 2 : Comparison of the proposed model with different existing models S. No

Variable

Proposed Model for India

DTe (2000)

Hijalmarsso-n & Vaiderpass 1992 Sweden

Weyman Jones 1992 England & wales

Pollitt 1995 england & wales.USA

--

Weyman Jones and Burns 1994 England & & wales --

--

London economics 1999 England & wales,USA. Australia, New Zealand --

Input

Input

--

1

Operating Expenditure

2

Units consumed

Output

Output

Output

Output

Output

Output

Output

3

Consumers

Output

Output

Output

Output

Output

Output

Output

4

Peak demand

Output

Output

--

Output

Output

Output

Output

5 6

Network length Transformer No./Capacity

Input Input

Output Output

Input Input

Input Input

Input Input

Input Input

Input Input

7

Labor

Input

--

Input

Input

Input

Input

Input

8

Service area

Output

--

--

--

--

Output

--

9 10

Capital cost Electrical product and Equipment Tariff rationalization

Input

--

--

--

--

--

--

Input

--

--

--

--

--

--

Input

--

--

--

--

--

--

Output Output

---

---

---

---

---

---

11 12

Losses

13 14

Power quality Commercial factor

28

2.1

INPUT VARIABLES

The inputs selected in the proposed production process model consist of those parameters which directly affect the infrastructure and working culture of the company. They can be classified into following categories: 1.

Operation & Maintenance Cost : Operating and maintenance inputs include (non-capitalized) expenditure on contractors, materials, spare parts, fuel and so on. In the preferred model specification, total operating and maintenance inputs are measured by annual expenditure rather than as a physical measure given the very diverse nature of these inputs.

2.

Capital Cost : Capital inputs represent a significant proportion of inputs utilized to provide energy distribution services (on a cost basis). The stock of capital can be measured in either physical or monetary terms. The stock of capital inputs that is used by distributors to provide energy delivery typically includes:

(a) (b) (c) (d)

poles and mains; transformers; buildings; and vehicles and other equipment.

3.

Network Length : There are few countries like Dutch which considers network length as output. However, it is felt tha considering network length as output will undermine the assessment of the ability of thedistributors to improve efficiency. The reasons for this are outlined below.

(a) . A network (poles, wires and transformers) is required for a distributor to deliver the fundamental output energy when the consumer requires that energy. (b) . A network results in costs. Inputs are normally specified in terms of costs whereby outputs are normally related to the goods and services for which consumers are prepared to pay an amount to receive. (c) Specifying the network as an output assumes that managers have no control over whether it is provided more or less efficiently. In the proposed model network length is taken as input, further network length measurement is done on the circuit kilometers (length between poles by number of circuits) which is in contrast with the other country models such as USA, New South Wales distributors, who consider route kilometers (the linear distance between poles regardless of how many circuits are supported). The network length can be sub divided in to two parts: (i) Overhead line (ii) Underground line 4.

Transformer capacity / No. of transformers : Different distribution companies can be compared by the transformer capacity / no. of transformers used them to meet the required supply demand while maintaining the quality.

5.

Labor Cost: In the proposed model labor is considered as separate input quantity. This is done in order to provide more detailed information about the potential sources of inefficiency.

29

6.

Electrical product & Equipment : The electrical product and equipment used by the company and consumers also need to be benchmarked which is not been considered in any of the existing models of benchmarking the distribution companies. The products used by the company and consumer such as transformers, switching devices, home appliances etc. are sources of magnetic field which may exceed permissible limit and hence affect health in long term. Also the harmonics and high current due to low power factor devices wuld increase distribution losses drastically. Futrther it would also contribute to reducing life of equipment and hence value of money would be possible for supplier. It is proposed that benchmarking desingn specification and performance levels are must for improving long term health of utility and consumer both.

7.

Tariff Rationalization : Rationalization of tariff structure will lead to a better supply side management along with demand side management. This would ensure that available quality power reaches to maximum consumers. Further incentivising collection through profit centers would lead to better collection efficiency and good returns to utility. In India, for example electricity supply to agriculture sector is highly subsidized. Thus according to the Indian system each class of consumers like industry, domestics and agriculture must have different benchmarks.

8.

Losses : Losses have been included as an input because in India there is a large amount of distribution losses taking place compared to other countries such as USA. Also there is a huge difference amongst the company distribution losses. There are two types of losses which are considered in this model : (i) Technical losses (ii) Commercial losses Electricity losses should have been included as an input; if no data is available at the distribution level then the approximation according to the company tariff order can be taken.

2.2

OUTPUT VARIABLES The outputs of the proposed production process model are those which greatly affect or are affected by the consumer. They are classified as follows:

1.

Units /Kwh delivered : Electricity distribution is about delivering energy from the high voltage network to low voltage consumer’s site. Two aspects of the energy in the distribution system should be considered: (a) The absolute level of energy that passes through the system in a period of time; and (b) The duration of peak load. The amount of energy delivered is important to the specification of the production process for electricity distribution as : (i) (ii) (iii)

2.

It reflects the degree to which the distributor is meeting its objective of facilitating the flow of energy to consumers; combined with the number of consumers, it indicates relative energy density; and along with peak demand, it accounts for relative capacity utilization and consumer mix.

Consumers : India is the second largest country in the world in terms of population (over 1 billion). Thus while benchmarking consumers as an output variable in Indian context; it has to be subdivided into two categories:

30

(i)

Type of consumers :

In this section we classify the consumers according to the amount of their electricity consumption and their operating voltage level. (a) (b) (c) (d) (e)

Small Large Domestic Industrial Agriculture

(ii)

Number of the consumers : Consumer number reflects the quantity of low voltage lines a distributor requires to connect its consumers, must construct and service. Consumer numbers act as a proxy for the number of connection points for each distributor. It is therefore important that these are included as an output for the distributors. The ratio of consumers to KWh accounts for energy density.

3.

Peak Demand : Incidental peak demand provides a proxy for the network and transformer capacity required by the distributor to allow the delivery of energy to consumers at peak times. This reflects the fact that the distribution system must be constructed to meet peak demand at its incidence, even if this is well above average demand. The inclusion of incidental peak demand ensures that a distributor that requires more inputs to meet relatively high demand is not penalized in the efficiency assessment.

4.

Service : Efficiency of the distribution company is judged by the service it provides to its consumer and hence the revenue collected by it. Thus it consists of two parts:

(i)

Revenue collection : Any distribution company in order to have a better infrastructure must have regular returns and maximum profit by implementing a better revenue collection policy. Thus it’s a managerial process and varies from company to company.

(ii)

Area serviced : Companies must also be compared by the amount of area that they are serving because it may be so that they are covering a very large area in which the population density is very less for example in hills, hence the consumer serviced to the area covered will be low. Where as a company doing business in metropolitan city, may be covering a small area but covers a very high population density. Hence their consumer serviced to the area covered will be high and hence should not be compared with the company doing business in a low population density area.

5.

Power Quality : Power quality of the energy supplied to the consumers is an important variable which distinguishes distribution companies according to following parameters:

(i)

Power factor : Low power factor of distribution products leads to more loss of power. Hence the products used by the consumer should be benchmarked by the company to give them an incentive for using high power factor products.

(ii)

Availability & Reliability : Availability is the time in hours the transmission system is capable to transmit electricity at its rated voltage from the supply point to the delivery point and it will be expressed in annual term. Reliability benchmarking should attempt to quantify the effect 31

of those factors such as lightning strokes which affect the normal operating conditions in the company service territory. Thus it helps in assessing the real performance of the company in providing reliable service. (iii)

Interruption time: In India due to shortage of generated power there are frequent power cuts which at times even exceeds to twenty four hours or more. Thus interruption time is an important parameter to be taken into consideration.

6.

Commercial factor : A company is judged by the value of its share in the market. This largely depends upon the number of consumers that are the part of that company and feel secured in investing their money in that company.

3.

EFFICIENCY EVALUATION Efficiency of the model can be assessed either on an input minimizing or output maximizing basis. An input minimizing orientation assumes that the output level is fixed and measures efficiency on the basis of minimizing the amount of inputs used to provide that output. An output maximizing orientation treats the inputs as fixed and measures efficiency on the basis of the distributor’s ability to provide as much output as possible with that given level of inputs.

In India there is a huge gap between supply and demand. It has a fixed amount of resources such as generating capacity, lack of funds etc. Keeping this constraint in view we try to maximize our output so as to provide better quality service to as many consumers as possible, rather than keeping the demand fixed and minimizing the amount of resources. Thus in the proposed model output maximizing orientation should be used. There are few unavoidable events such as earthquake, storm etc. which lead to a long interruption in power supply to the consumers. Thus the quantity and quality of the power supplied to the consumers during that period should not be considered while calculating the output efficiency of the companies 4.

CONCLUSIONS The deregulation and privatization of the power sector are going on in India. With the introduction of the Electricity Act, 2003 there is more freedom of open access to generation, transmission and distribution. With more and more active participation of private companies in the field of electricity distribution there is a need to assess their efficiency. This is important so to promote a healthy competition amongst the companies with an intention of providing maximum benefit to the consumers.

Benchmarking is widely regarded as a ‘corporate miracle’ and has become popular among practitioners of various disciplines. Benchmarking of distribution companies has been done in few countries like USA, England & Wales. The experience gained from them promoted to use benchmarking for the distribution companies in India. But the production process model used by them cannot be used as such for doing the qualitative and quantitative study and comparison of distribution companies in India. For example, the model implemented in USA does not consider interruption time, losses and availability. Whereas these factors have a strong impact on the socioeconomic development and hence are considered in the proposed model for the Indian system. 5.

FUTURE PROSPECTS At present only the proposed Production Process model well suited for the Indian system is introduced. The ongoing and future work aims in doing the detailed case study, whose success will lead to its practical implementation. With the successful practical implementation of

32

this, distribution companies operating in India will not only be able to increase their efficiency but will also link themselves to the world class performers in the arena of power sector. REFRENCES (1) (2) (3) (4)

(5) (6)

Suresh P. Prabhu, Minister of Power “INDIA Power Sector Reforms,” May, 8, 2002. American Productivity and Quality Centre “What is benchmarking,” APQC Report USA, 1997. Nillesen P., Telling J. “Benchmarking distribution companies” EPRM Electricity March, 2001. Lassila J., Viljainen S., Partanen J., “Analysis of the benchmarking results of the electricity distribution companies in Finland,” IEEE Postgraduate Conference in Budapest, Hungary, Aug.11-14, 2002. “Efficiency and benchmarking study of the NSW distribution businesses,” London Economics, Feb. 1999, www.ipart.nsw.gov.au. Lawrence Kaufmann, David Hovde, “CitiPower Performance: Results from International Benchmarking.”

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SESSION – 2 Distribution System Optimisation • Planning for Efficiency, Adequacy and Security • GIS Mapping and Customer Indexing • Energy Auditing and Accounting • Role of IT & Telecommunication Chairman : Sh. A. K. Sah, Former Chairman & Managing Director, NTPC and Chairman – Premier Mott MacDonald Key Note Speakers : i)

Dr. M. V. Krishana Rao, Director, Global Energy Consulting Engineering Pvt. Ltd. “GIS Mapping and Customer Indexing”

ii)

Sh. Sumantra Banerjee, MD, Calcutta Electric Supply Company (CESC) “Condition Monitoring of Power Transformers in Service”

iii)*

Sh. Kumud Goyal, KLG Systems, “Integrated Meter & Loss reduction strategy”

iv)*

Sh. Amitabh Singhal ALSTOM LTD. “Distribution Network Optimization and Planning Studies”

Additional Papers included in Binders : 1.* “Work for Electricity Utilities” Shri Arijit Mitra, Noida Power Co. Ltd 2.*

3.*

“Integrated Resource Planning and Supply Side Management in Power Systems” by Dr. P.K. Kalra, Sh. Yogesh K. Bichpuriya, Sh. Vipin P. Singh, IIT Kanpur “Advance Methods of curbing Voltage Instability in Distribution Network” Sh. A. B. Bhattacharya, Lecturer, Electrical Department, Sh. A. S. Raghvendra, Assistant Professor, Electrical Engineering Department, Sh. A. M. Mulla, Sr. Lecturer, Electrical Engineering Department, Rajarambapu Institute of Technology, Islampur, Sangli, Maharashtra-415414 and Sh. H. T. Jadhav, Sr. Lecturer, Electrical Engineering Department, Tatyasaheb Kore Institute of Technology, Warnanagar

4.*

“Consumer Indexing, Network Information Management Systems - Asset Management” Anjuli Chandra, Director, Central Electricity Authority

5.*

“Prefabricated Distribution Substation - A Complete Electrical Equipment” (Technical Choices, and IEC Standard Evolving) Bernard Teissier, Areva T&D, Mvb Drc & Yann Fromont

6.*

“Application of IT in DistributionSystem for Revenue Improvement” by Shri V.N. Manohar

* Papers received by the time of compilation

Increasing Efficiency & Reducing Losses with Minimal Cost Investment for Distribution Utilities By Manoj Gupta KLG Systel Ltd.

Agenda • • • • •

Company Profile Services Consultancy Software Project Summary

KLG Systel Ltd … • • • • • • •

In Power Sector since 1990 ISO 9001 Certification Publicly listed on the National Stock exchange 9 offices in India 1000 employees R&D Center spread over 7000 sq. feet at Gurgaon Active participation in various power forums as ASSOCHAM, NASSCOM, FICCI

Services Revenue Management • Consumer Database Updation/Maintenance • GIS Mapping & Consumer Indexing • Meter Reading (HHC/HHC with Digital Camera) • Spot Billing • Collection (Smart Card/Cheque/Credit Card) • Meter Management • Connections/Disconnections VIDUSHI-IT Backend behind the entire System Energy Auditing/Accounting(11 KV Feeder & DT level) Evolution of Vidushi Ultimate objective of all Indian Distribution Utilities: • Ensure Customer Satisfaction • Improve power delivery and operations • Revenue Realization Critical problems which they face : • Lack of continuously updated database • Lack Of database Management • No track of energy accounting • Lack of Information management & sharing

What Utilities Need A cost effective and comprehensive solution/tool which • Addresses the infirmities in the existing mechanisms and systems. 35

•

•

Seamlessly manages operational and customer data across the enterprise, distributing operations information and applications to everyone who needs it. And Ensures immediate and tangible returns.

VIDUSHI as a Software Tool Aims At • • • • •

Realization of dual objectives – Optimizing of asset utilization & efficient revenue realization.” Making possible Energy Accounting Linked dynamically to metering and network schematic. Relates to all activities being executed by Indian utilities under APDRP Is developed by personnel who have hands on distribution experience and insights into field methodologies and technologies.

Capabilities • • • • • • • • •

Consumer Indexing & Linking on GIS MAP Maintenance of consumer database - Commercial and Personal details Creation of network schematic representation Energy accounting & reconciliation Asset Management/Repository Seamless Integration with Billing Systems Power system study software CRM Asset Management/CMMS

Circle 33/11KV Substation

Consumer Indexing”integrated with GIS Mapping • • • • • •

Inputs of survey entered into database for Kno. Matching, data cleaning and updating Segregation of consumer feeder wise, DT wise,11KV feeder wise and upstream. Consumer Index generation for each consumer using Vidushi Interlinking to GIS map using Vidushi Report generation for all anomalies reported Route map for meter reading

Distribution Transformer

Pole

Consumer

C

P

T

D

L

N

Resultant Advantages • • • • • • • •

Identification of Distribution Network Immediate intimation for fault attendance Fault / breakdown analysis (feeder/ transformer wise) Generating MIS Distribution transformer, feeder wise Transformer / Feeder wise energy audit Handle request for new connections Tracking customer meters and recording meter changes, meter re-calibration etc. Tracking customers who are to be disconnected or reconnected as required by the billing system 36

37

11 kV Feeder / DT Energy Auditing” Energy accounting involves the following activities: • Installation of CT Meters on the DT Secondary • Recording the readings at the DT secondary/11 kV Feeders • Calculating the ATC losses • Generation of reports like Energy Consumption DTwise, Feederwise. • Energy Consumption and ATC loss details category wise. • Keep track of customer profiles, energy consumed and revenue generated from each category

Distribution Utility Consulting Utility Network Analysis • Loss Diagnostic Studies (As Is Analysis) Utility Network Planning • Load Forecasting • Network Optimization (Focused To Losses Reduction) • High Voltage Distribution System Planning HV Equipment Diagnostics

Loss Diagnostic Studies • • • • • •

Collection and verification of network data Network modeling Network analysis (Load Flow: Symmetrical & Unbalanced) Results verification (Measuring DT / Feeder current, Power, Voltages) Load re-adjustment in the system modeled to reduce the mismatch from measured data (Current or power) Calculation of Network Losses, Voltage regulation, Line Flows and major problematic areas

11 kV Network Optimization • • • • • • • • •

Optimal switching point location Proper tap setting of the transformer Optimal sizing of the distribution transformer Optimal location of the distribution transformer Optimization of the reactive power compensation Feeder wise load forecasting Proper sizing / routing of the conductor / cable Outage Management / Contingency planning Optimization of the maintenance scheduling

High Voltage Distribution System Aimed to Improve upon • I2R Losses (Typically 10-15% in LT Network) • High LT / HT Ratio (Typically 50) • Voltage Regulation (10-15% in LT Network) • Commercial Losses (As High As 50%) • Downtime of Supply • Energy Accounting System (No Energy Accounting Practice for LT Network 38

High Voltage Distribution System Advantages • I2R Losses (About 1%) • High HT / LT Ratio (Typically 1) • Voltage Regulation (1-2%) • Downtime of Supply (Lower) • Commercial Losses (Almost Nil) • Energy Accounting System (Normal Practice to do on 11 kV)

High Voltage Distribution System Design Process • Field Survey (Load estimation) • Mapping and Linking (Service Area Map and Location of Power Sources) • Network Design and Planning • BOQ Generation • Pay Back Period Calculation

High Voltage Distribution System KLG SYSTEL Ltd. Experience • BSES Ltd Presently Executing HVDS Design For 66 Colonies (About 70000 Consumers) •

Jaipur Discom Design For Rural HVDS Electrification (Under Tendering Process)

Software Tools Available Network Planning and analysis • ETAP Power Station • PSCAD / EMTDC • SPARD Network Management Information • Vidushi (In House Developed)

39

Distribution Network Optimization and Planning Studies Amitabh Singhal

Daniel D’ Hoop Jean-Pierre Muratet ALSTOM LIMITED

Dr Riaan Marshall

SYNOPSIS Distribution networks in any given distribution system, develop gradually along with the load growth in the area. The load growth takes place not only in terms of load increase at a given point but also geographically, over the years. Despite the best efforts to achieve a target network, the unpredictable nature of load growth leads in many cases to a different network, which was not originally planned. It can therefore be said that the distribution networks “evolve” over a period of time. This behaviour increases the probability of the distribution networks to end up in a non-optimum design, with good scope for betterment. Thus, it is a good idea to have a relook at the existing or the “evolved” distribution networks and “re-plan” them at a later date when the load growth or the load growth pattern has become relatively stable. Such an exercise will result in relocation or rendering useless, some of the existing equipments in the network. Hence it is important that this exercise is taken up at a time when the existing equipments have lived a considerable time of their lives, so that the changes proposed do not result in scrapping of relatively new equipments and is economically better justified. Many of the distribution systems in India, which have been in existence for few decades have now reached a stage where they need such a “relook” and “redesign” along with the upgrading and revamp of the “as-is” existing network. The authors of this paper have recently carried out such studies for two of the biggest urban distribution networks in India. This paper discusses the approach and methodology covering the following aspects. 1.

Major problems related to existing distribution networks

2.

Different components of network optimization and planning (equipment standardization, equipment life cycle, network architecture, target network, invest when necessary)

3.

Few of the possible approaches for optimization (as-is to green field approach)

4.

Implementation strategy based upon the results of optimization

The discussions in the paper correspond to the optimization and planning of the medium voltage distribution networks (usually 11 kV), i.e from power transformer up to the distribution transformers.

1.

MAJOR PROBLEMS RELATED TO EXISTING DISTRIBUTION NETWORKS

Some of the issues associated with the existing distribution networks are as follows – A

Non-standardization Large distribution networks may have equipments of various designs, manufacturers, technologies, ratings and sizes. This means larger investments in maintaining spares, tools and expertise for maintenance of these varied types. Interchangeability also becomes a problem in case one asset has to be shifted to another place to make optimum use of available resources. Thus standardization on few equipments ratings, sizes and types is an important part of the optimization process. 40

B

Non-availability of network information Availability of network information is missing. The information could be of network physical data such as feeder lengths, type of cables/conductor, cut-off points, present loading etc or information such as load growth, state of equipment, type and frequency of faults etc. In many cases, the information is available with individuals for their respective areas, but is not available on paper as a common knowledge. Hence, in order to get the complete picture for overall assessment of the state of the network, data collection becomes a task in itself.

C

Old Equipments This problem is due to very old networks due to which many equipments in service are outdated having outlived their lives. The manufacturing companies might have closed down or the technology used might have become obsolete, both factors leading to non-availability of spares and proper service. Thus the equipments are more or less non-maintainable.

D

Non-optimized resources As already discussed, due to the evolving nature of the network, many of the network elements remain under-utilized or over-burdened. Some feeders could be very long or highly overloaded while some could be underloaded. The overall losses in the network increase on account of this situation and cause voltage drop problems too. Also, if customers are not evenly spread out over feeders, the tripping of a single feeder could severely impact network performance indicators such as for example “Customers Minutes Lost”.

E

Absence of backup supply The distribution networks in many cases might not have a planned back- up, in case of outages in the network. Thus even if the power is available, due to a fault in one section of the cable, all the consumers connected to the feeder may get disconnected. It may be possible that backup could be provided after making some temporary arrangements but this takes time and may also result in further trippings due to overloadings. Thus the energy not served is high as faults are frequent due to old age of the network elements.

F

Non-coordinated protections The protection relays employed in different sections of the network, in most cases, are noncoordinated with each other. This could be due to different type of relays, response times, differences in breaker opening closing time, mal-function of relays, breakers etc. This results in either the fault not getting cleared in time or tripping of upstream breakers for a downstream fault etc. Equipment damages and accelerated loss of life occurs due to this situation.

G

Poor metering (on account of state of meters, tappings etc) is one of the major problems, which result in loss of revenue to the utility. However, this is an altogether different subject and is not dealt with in this paper.

2.

DIFFERENT COMPONENTS OF NETWORK PLANNING AND OPTIMIZATION When taking up the task of renovation and modernization of distribution networks, an easy approach is to replace the old and damaged equipments with another equipment of same rating and to replace the overloaded equipment (transformers, cables) by a higher rating equipment, assuming some margin for future growth. If the changes are carried out in this fashion, without considering the role of relevant part of the remaining network, it becomes a step towards ending up with an unplanned network. 41

Various factors need to be considered while doing this upgrading in order to maintain the utility of the investment made for a long period of time. A

Equipment Standardization

This is one of the key elements of the optimization process, wherein the ratings and types of equipments are standardized. Thus a utility may decide to have distribution transformers of 25 kVA, 200 kVA, 630 kVA and 1000 kVA rather than having the complete range of ratings available in the market. This approach provides savings in terms of fewer inventories to be maintained, better purchase prices due to increased quantity of fewer ratings, better control over maintenance and required expertise. B

Equipment Loading Capability

It is a matter of discussion as to what should be the maximum allowed loading on a particular network element, beyond which it should be replaced with upgraded capability. In general, for the purpose of planning, it may be prudent to consider loading upto 95% under normal conditions and up to 100% under “N-1” condition. The equipments are supposed to be rated for their full capacity and therefore should be allowed to be used up to their full capacity. However, it is another matter that as an operational practice, a utility may start taking action, once the load on a network element reaches, say 90% of its capacity, so that by the time replacement is arranged, actual loading might have increased to 95%. A lower target loading of a network element results in over-investment and wastage of resources. C

Target Network Approach

A target network approach means, to design a network for say 20 years from now and then plan and implement changes in the existing network step by step to achieve that target network in 20 years. Any addition or change in the network is by a planned action, which is part of the target network. It is important that if a new equipment of certain rating is installed, it is loaded to a reasonable capacity throughout its lifetime. For example if a presently overloaded cable section is changed today with another cable of higher cross section, it is expected that load on that cable section remains higher than the capacity of the replaced cable section. However, if two years later a new feeder is laid, splitting the existing feeder (of which the replaced section was a part), the load on the replaced cable section may reduce to a value, which was very well within the capacity of the old section. Thus, the investment made today becomes redundant two years later, and prevent equipment redundancy. This is possible only when an overall view of the network is taken considering the complete or at least the relevant integrated parts of the network. Two aspects are important in planning the target network. (i)

The first is that the time horizon of the target network should match the equipment lifetime. As the equipments are generally expected to serve for at least 20 years, this can be taken as the reference.

(ii)

The second aspect is that having a target network does not mean that all investments of today should be made for overloads for the 20th year. A target network of 20 years later may not also provide a clear picture of what action has to be taken to solve a particular overload, say 7 year hence. Thus, it is important to have the target network of year 20 to be defined for few in-between “snapshot years”, say for example year 1, year 5, year 10 and year 15. These 42

networks of snapshot years should be a subset of the target network of year 20. Then actions in the network can be easily identified and lead to investment only when necessary. A time span of say 5 years can be a good time period for spreading the investments and also having an “idle” time in between (time when no change in the network is anticipated). D

Optimal network architecture

It can be debated that what kind of network architecture is optimal. Many types of network architecture can be employed. Some of these are -

Spindle from & to one substation Spindle between two substations Backup cable Fence Tree Daisy Chain Double supply

Each of the above has relative advantages and disadvantages. Relative comparison of these structures on the basis of a uniform distribution of loads is given below :

Planning an architecture can be more relevant for a new network, as existing networks could be a mix of the above types. However, an assessment can be made for an existing network as to which architecture can be better employed. E

Backup Philosophy

In order to increase the availability of supply, it is always better to provide every load point with minimum two sources. Thus one source can feed power under normal conditions, while other can supply if the first source develops a fault. Normal practice is to design the network with "N-1" approach wherein failure of 1 network element does not affect the supply to any load. However, keeping a provision of backup for every load point may not be economical and therefore it may be prudent to provide the backup for all loads of certain size. The cut off value may depend on the type of load, but a value of 1000 kVA could be considered.

43

3.

POSSIBLE APPROACHES FOR OPTIMIZATION

A As already discussed, one of the approaches during revamp of the distribution network is to take care of overloads as and when they appear. In this case, the target network is suitable for an "N" condition only. B The second approach, which is also discussed above, involves an "N-1" approach. The actions taken in this case are not only meant to remove the overloadings but also to ensure that all actions remain "N-1" compliant. The optimization process is different in this case. Hence a cable section overload may be better solved by a new feeder rather than by changing the section itself, as the new feeder will also act as a backup source to the loads. C The third approach could be to plan an altogether new network, which can be laid while the existing network is in service and as per the desired network architecture. This approach can be termed as the green field approach. Once in position, it can be energized by switching the loads from the previous equipments onto this new network. This approach provides complete flexibility but obviously leads to higher investments. This may be economical in situations where existing cables are very old and need total replacement anyway. D The fourth approach could be, to not only plan the new network but to also change to a higher distribution voltage (say from 11 kV to 22 kV). This option obviously needs very high investments but has the advantage of reducing the losses and to be able to supply more power through the same corridor for cables and lines. This option may be resorted to in cases where an existing network has undergone a substantial damage due to for example earthquake, war, etc. Under average conditions, the second approach may be the most viable, considering the increase in reliability and availability aspects, and considering that electricity has become a basic human need and must be made available at all times. The benefits to society at large for this option will prove to be much more, thus making it the most optimum solution.

4.

IMPLEMENTATION STRATEGY BASED UPON THE RESULTS OF OPTIMIZATION

It is not only important to carry out a planning study and have a plan, but it is more important to have a methodology for its implementation. A plan for 20-30 years may throw open a list of large investment to be made immediately (and specially when the present state of the network is not very good). Immediate steps could be to upgrade / replace the network elements that are overloaded at present. The solutions proposed in the planning study, which relieve these overloadings, should be taken up first. This should be followed by solutions, which are proposed for providing backup supply to the loads. Normally the plan should identify this aspect for the investments proposed. During the course of implementation over the years, at times it may appear worthwhile to deviate from the target solutions, but this temptation should be avoided. On existing networks, which are already matured, the projections can be made relatively safely provided the data on past load growths is available. For networks, which are still growing at faster rate, the projections could be difficult to make but at least a plan should be made. As the network grows and actual loads appear, the implementation could be made ahead or later than what was planned to take care of the actual situation. What is important is that the actions taken are always in line with the plan already prepared towards the target network.

44

Situations may arise when the target network itself appears to be faulty (if the assumptions made at planning stage prove to be different). In such cases, a course correction can always be made by revising the target network itself.

5.

CONCLUSIONS

It is the firm belief of the authors that network planning and optimization, if carried out considering the issues discussed in this paper, will result in definite value add in the process of renovation and modernization activities going on at an accelerated pace in this country at present. The investments made in this effort at this stage will payback many times over in the long run.

VARIOUS TYPES OF NETWORK ARCHITECTURES

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Making Investments in AM/FM/GIS Solutions Pay for Electricity Utilities Arijit Mitra Noida Power Company Limited Alpha II Sector, H Pocket Greater Noida-201308 Uttar Pradesh, India

Introduction AM/FM/GIS systems have currently become one of the important thrust areas in the modernisation exercises being undertaken across the country to set right electricity distribution systems. While several projects have so far been undertaken to implement AM/FM/GIS systems, there is often a lack of clarity as to how benefits can be derived from such systems on a sustainable basis. Consequently, projects conceived on the basis of such a limited vision have sometimes failed to justify the expectations and more importantly, the investments made. This paper discusses some of the possible approaches that can be utilised to make investments in AM/FM/GIS systems generate returns on a consistent basis.

Evolution of AM/FM/GIS Systems The term automated mapping/facilities management or AM/FM, in short, connotes a single application among many that are offered by today’s geographic information systems (GIS). However, early implementations of AM/FM systems were distinct in nature, based on a computer-aided drafting (CAD) platform that was linked to a separate database of textual (non-graphical) information. Since AM/FM systems were typically CAD-based, entities defined under AM/FM systems could be programmatically “connected” to one another, using a parent–child relationship. Therefore, these systems modelled the electrical or pipe network of the utilities well. However, as these systems were not capable of handling areas or polygons efficiently, graphic entities other than network elements were not supported well. Unlike AM/FM systems, GIS systems were designed to handle geographic entities. The topological data model used in the GIS systems could handle areas in the form of polygons with the same facility as line and point features, and hence could be used to carry out analysis of complex spatial relationships, which AM/FM systems were not capable of. Thus AM/FM functionalities were restricted to basic facilities management and could not extend beyond rudimentary spatial analyses. Because of the underlying network data model of AM/FM systems, the use of such systems were restricted to specific departments such as engineering or design, whereas the topological data model of GIS systems allowed GIS data to be shared across functions. Realising the limitations of AM/FM systems, AM/FM vendors began to develop spatial analysis capabilities to add to the product features. Simultaneously, GIS vendors began to develop network tracing and analysis capabilities in GIS software. Subsequently, with a convergence of the functionalities of the two systems, a new product family came into existence that was known as AM/FM/GIS systems.

Current Approaches To arrive at a successful strategy of harnessing the benefits of investing in a facilities management project for an electricity distribution utility, one has to be mindful of the fact that restricting the scope to mere network modelling and analysis will result in a myopic vision that will come to the benefit of only a few functions for a short duration. In the process, a range of possibilities of sharing

46

information across functions will remain unexplored. Also, accurate network data collection and updating will become difficult in case relationships with spatial entities are not adhered to. Soon after project completion, the data that will come in for updating will often be of such poor quality that network analysis will no longer result in credible information. A holistic approach, on the other hand, will not only allow extension of scope and hence benefits to productive areas, but will also ensure that data is validated against multiple sources and remains credible. A simple example is that if material lists used in network design are not validated against materials used in inventory and purchasing systems, the Bill of Materials generated through a network design program will be of limited value for generation of Work Orders or Material Requisitions. Current approaches in deployment of facilities management systems need to guard against the limitations outlined above to ensure integration of the systems with the daily work practices of organisations, without which the systems are unlikely to generate the desired value in a sustained manner. The areas in which these systems can be deployed to the advantage of the enterprise are discussed below. In case implementation is attempted in all these areas, it is advisable to avoid a big-bang approach and allow the implementation to be gradually scaled up as processes within the organisation mature and become ready to adopt the degree of automation needed.

Pitfalls in Implementation Implementations of AM/FM/GIS systems can easily hit a snag if attention is not given at the outset to certain known pitfalls. The most obvious challenge is collection of data, both geographical and electrical. The nature of the exercise depends on the scope of the project, location of the area and prior availability of network maps. In case the project aims at extending the scope upto the level of LT customers, the burden of geographical data collection becomes significant. If the area is a developed one, where detailed and accurate cadastral maps are already available, the burden is eased to a certain extent. Also, if the utility has historically maintained network maps, collection of network data also becomes simplified. However, the area that calls for as much attention as data collection is updating of geographical and network data following project completion. In case a viable approach is not developed at the very outset, the implemented system will soon fall out of sync with real-time information and lose relevance. Data modelling is another aspect that needs special attention, as an inadequate design of the data model can not only limit the scope of integration of the AM/FM/GIS systems with other related systems, but also hamper design of the AM/FM applications themselves. It is therefore advisable to undertake this exercise carefully and adopt, if possible, industry-standard data models that have stood the test of prior implementations. A key component of implementation strategy for an AM/FM/GIS project is managing the change that the implementation is going to bring about in the daily work processes. As an integrated AM/ FM/GIS system is bound to have an impact on a number of processes and vice versa, and as an authentic database of asset information is critical for the success of the initiative, it is essential to inform, educate and motivate all process stakeholders throughout the course of the project about the impact the system is likely to have, the manner in which processes have to be redesigned to take advantage of the system and the delineation of responsibilities that the stakeholders have to take up to realise the goals of the projects. These efforts have to be buttressed with extensive training as Geographic Information System is a specialised software that requires users to develop a higher level of skill than normal office or accounting applications.

Network Design Network analysis tools are available as add-on applications from several third-party vendors. These tools carry out analysis of electrical network information created in the AM/FM/GIS environment

47

and indicate scope for optimisation of performance of the network based on financial parameters, such as Payback Period, etc. These tools can also be considered as effective planning tools at the time of planning for network expansions. Considering the fact that expansions of distribution networks in the Indian context are rarely subjected to sophisticated planning tools, there is considerable scope for generating return on investments through familiar network engineering approaches such as reconductoring or network reconfigurations. Network analysis tools can help in identifying the locations where such network engineering exercises can be undertaken and generating data regarding the financial implications. However, too often the scope of AM/FM/GIS projects is restricted to technical analyses only, limiting the extent to which benefits can be reaped from such projects. An important area, where AM/FM/GIS systems can be used for process automation, is in the planning and design of distribution networks. Where network design applications can be integrated with work order management systems, the extent of savings through process automation can be maximised. As design applications serve the two-fold objective of automating the design process and optimising the individual designs, reduction in both material and labour cost of construction can be achieved. A downstream effect is optimisation of materials held in inventory in connection with network construction, all of which should translate into monetary savings. Automation of the design process also results in reduction of cycle time, allowing the utility to serve its customers better.

Outage Management Add-on applications for managing operations of a dispatching centre are available which have interfaces with AM/FM/GIS systems to utilise geographical, network and customer information in locating customers affected by outages, predicting failed devices, directing repair crew, keeping track of repair operations, updating call status, determining correct switching sequences and collating information on duration of outage, cause of failure, materials replaced, etc. on closure of trouble calls. The advantage is, on one hand, to manage the process of attending to trouble calls, using the software as a decision-support tool, and on the other hand to compile a comprehensive outage database that links each outage to cause of failure of device as well as to customers affected by the outage, lending itself to accurate analysis of cause and impact of outages, including calculation of reliability indices, cost incurred to service outages, etc. Routing of crew is another related area where an AM/FM/GIS system can help generate savings in distance traversed.

Asset Management As the distribution network of an electrical utility comprises bulk of the fixed assets of the enterprise, an AM/FM/GIS system provides comprehensive assets data to the utility, which can be utilised through an add-on application to carry out preventive maintenance, collect data regarding maintenance done during breakdowns, track condition of assets and generate service orders for maintenance or repair when necessary. Thus the facilities data in a GIS system can be utilised to enhance the overall productive life of various network assets.

Integration with Other Systems Integration with systems such as SCADA, Customer Information System, Material Management Systems and Call Centre applications can help multiply the returns that an enterprise can generate from an investment in an AM/FM/GIS system. Integration with SCADA allows network analysis software to process system load information on the basis of real-time network parameter values available from SCADA. Integration of SCADA with outage management systems allows status of network attributes such as switches and transformers to be updated with real-time information. 48

Depending on the nature of SCADA implementation, fault analysis on the basis of data from protective systems can also be carried out using data from both SCADA and GIS. Network designs can be validated against material lists and converted into work orders if an interface exists between Materials Management System and network design software. Integration with Billing System allows Energy Audit to be carried out using network topology information available in AM/FM/GIS system to yield accurate calculation of energy balance. Integration with Customer Information System is essential for keeping customer data in outage management systems current and allowing call tracing on the basis of location, telephone number, etc. In case of planned outages, notices can be generated for affected customers through an automated process if an appropriate interface exists. Integration of Call Centre application with outage management system is essential to allow call information to be converted into trouble orders in outage management system. Trouble orders generated in outage management systems can also be converted into service orders if integration with work management system exists. In many instances, a stand-alone AM/FM/GIS system can generate information, which in the absence of validation against related systems, may not be relevant or useful. For example, if the customer information is not updated correctly in the AM/FM/GIS system, outage management system cannot function effectively, neither can system load be estimated with reasonable accuracy. In the absence of interfaces between related systems, data needs to be duplicated to keep it current and integration therefore results in considerable savings in manpower costs.

International Trends In international utility markets, integration of GIS and Work Management Systems embracing the areas of job design, crew management, maintenance optimisation, etc. has become a critical component of operations management. Apart from Work Management Systems, the focus of integration has also been on mobile systems, engineering systems and outage management, as well as back-end systems such as financials, procurement, budgeting and accounting for regulatory bodies. The attached graph will show that energy companies worldwide are leading other businesses in terms of highest spending on application integration and data warehousing.

It has been observed that integration of GIS with other related systems increases the value proposition exponentially. In fact, it is difficult to assess the return on investment in a stand-alone 49

GIS system. But when a GIS system is integrated with three or more systems, the payback curve has been found to shrink from as long as 10 years to even two to three years. While the most tangible benefits have accrued from work management and outage management systems, their performance has been found to depend on the quality and efficiency of the asset management process. The overarching strategy has been to use geospatial data to integrate operations and assets information so that utilities can make better decisions, schedule work more efficiently, lengthen the useful life of assets, restore outages more quickly and respond to customers faster.

Conclusion The real value from an investment in an AM/FM/GIS system can thus be gained when the use of the system is enhanced through integration with add-on applications. However, as elaborated above, in the absence of spatial data, most of these applications will fail to generate significant advantage. A successful GIS implementation in an electric utility would allow access to a wide section of the workforce, whose functions are related to the network and the customers, through integrated information systems that deal with geographically dispersed facilities or customers.

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Integrated Resource Planning and Supply Side Management in Power Systems Dr. P. K. Kalra*

Yogesh K. Bichpuriya*

Vipin P. Singh*

*Indian Institute of Technology, Kanpur

Abstract The electricity industry in India continues to evolve due to regulatory changes and market forces. It has moved on from the vertically integrated system to open access market. Through overt public policy and an emerging industry structure, the wholesale competitive marketplace has evolved. Regulatory changes are likely to be significant, particularly with regard to how the existing system and operated in the future. These ongoing changes in the structure and regulation of industry require changes in approach to resource planning. Given the potential for commodity markets (both natural gas and electric) to exhibit price swings, or volatility, alternative resources plans must be evaluated in terms of their exposure to this volatility, in addition to their long-run average costs. Furthermore, unpredictably in the future costs of new supply alternatives arising from fuel cost( primarily natural gas price) provides analysis leading to a comprehensive portfolio and strategy for supply acquisitions, transmission investments and demand side management along with the consideration of environmental issues. The purpose of IRP is to provide reliable, safe and least cost electric service to its customers. This paper pays emphasis on supply side management and its integrated resource planning. Keywords : IRP, supply side management, demand side management, cogeneration, renewable energy, environmental issues.

1.

Introduction

The Indian power sector has been increasing its installed capacity, from 30,000 MW in 1981 to over 100,000 MW in 2001. Despite this growth in supply, its power systems are struggling to overcome chronic power shortages and poor power quality. With demand exceeding supply, severe peak (around 18%) and energy (around 10%) shortages continue to plague the sector. Shortages are exacerbated by inefficiencies in power generation, distribution and end-use systems. The inefficiency on the supply side is due to unavailability of better quality of natural resources, less use of newer technology and lack of awareness. The inefficiencies in the end-use systems is due to irrational tariffs, technological obsolescence of industrial process and equipment, lack of awareness, and inadequate policy drivers (such as energy efficiency standards and labeling system, financial incentives) in India. Another great concern is biological and adverse effect of generating plants and electrical equipments on human beings and environment. As the deregulation of the electric power industry progresses in India, the basic structure of power systems will change drastically. For example, it is expected that small-scale distributed generation facilities (such as photovoltaic, fuel cell generation, etc.) and dispersed type energy storage systems (such as secondary battery, electric vehicle, SMES, etc.) are installed in the demand side or the power distribution systems. The introduction of a disaggregated, competitive electricity supply industry will affect the appropriateness of various planning models currently used. One such approach that has been significant in promoting energy efficiency and demand side management in a number of countries is Integrated Resource Planning (IRP). 2.1 What is integrated resource planning? Integrated resource planning is a planning process that seeks the least cost option for meeting customer’s electricity demands. In determining the least cost option, IRP evaluates all supply and demand side options over a forecast period from a societal perspective. IRP implies significant regulatory oversight which can be applied by a number of means. 51

In its broadest context IRP includes all energy forms and the whole national energy market. IRP can also be implemented for the electricity industry, or at an individual utility level. A key feature is the regulatory oversight of the process. IRP can take a variety of forms. At one extreme, government may exert significant control over the process. This may involve establishment of an independent energy planning body with responsibilities including: 1. 2. 3. 4. 5.

Development of IRP procedures, including costing of environmental externalities; Oversight of public consultation and review of plans; Amendment of plans; Setting and reviewing utility performance criteria identified in the plans; Reviewing and approving major capital investment decisions.

At the other extreme, utility may simply be required by government to periodically publish report on its strategic planning process, and seek public comments. IRP may be initiated in two main ways: 1. 2.

By governments applying IRP across one or more major industry sectors- this could be termed as “mandatory IRP” By individual electricity businesses, applying IRP only within that particular business- this could be termed as “business-related IRP”.

Whatever the form of the IRP, the following elements are common: 1. 2. 3. 4.

It is a continuing and iterative process, ideally planning, implementation and evaluation; It is an attempt to balance long and short term goals, and to meet multiple goals; All resource options are compared in the one forum and a portfolio approach is promoted; Public discussion and debate are involved.

Mandatory IRP works well in an electricity industry composed of vertically integrated monopoly electricity businesses. In an industry structure where the functions of the electricity industry have been unbundled into separate businesses, both mandatory and business related IRP can still be undertaken in the natural monopoly elements of the industry, i.e. the transmission and distribution network sectors. 2.2

Integrated resource planning in electricity industry

Many countries are looking for “deregulating” or “restructuring” their electric power industries. The basic purpose of this restructuring is to open electric power industries to competition among suppliers. These efforts are considered to provide better quality of electric supply to consumers at a lower price. There is a point to consider that how the IRP process will include the social benefits with the deregulation of the electric power industry. The electricity planning problem in many developing countries is more complicated as compared to developed countries. Generation of power is difficult because electric power industries require large capital investment. The developing countries have a problem to substitute investment in cost-effective reductions in electricity use for investments in power plants. The combined planning for increasing electricity capacity to meet growing demand with cost-effective reductions in use of electricity is called integrated resource planning. The growing demand for electricity throughout the world is met by electric utilities by building more power plants. Increased burning of fossil fuels in these power plants could pollute the atmosphere. Burning of fossil fuels in power plants would produce more CO2 which contribute to global warming. 52

In developing countries due to high growth in power generation the CO2 emissions grew fastest in last few years. Over last two decades the CO2 emission increased by about 80% in these countries. The combination of resources different from those used in the past and the integration of these resources in a cost effective way could ease the health, economic, and environmental effects of increased demand for electric power. Environmental problems such as emissions of CO2 gas from the power plants are more complex while building the power plants to meet the increasing demand for power. According to the environment regulatory bodies the countries should encourage the programs to limit the greenhouse gas emissions. IRP process may alter the pattern and the levels of electricity demand and constructing nonconventional power plants. IRP takes the future assessment of energy supply and demand. It combines them while considering environmental and social factors, energy efficiency and load management programs, and different limitations of the resources. Technically it should treat the demand side resources and the supply side resources equally. 2.3

How the integrated resource planning process works

1.

5.

The integrated resource planning process analyses the present situation of existing resources, future demand for electricity and identifies the reliability of service, environmental impacts and economical price for the supply. IRP identifies resource options that would compensate for discrepancies between expected loads and existing capacities. The options are evaluated considering the economic, social and environmental factors. The resources are combined to meet the demand for electricity in such a way that satisfy all regulatory issues and avoid risks. Finally the plan, thus obtained, is implemented.

3.

How to do Integrated Resource Planning in India

3.1

Supply side management

2. 3. 4.

The elementary problem faced by the power sector is the poor financial conditions of State Electricity Boards (SEBs) or successor entities in most states. Over the years SEBs have been causing an increasingly larger drain on the State Government budgets, contributing to 10-15% of the state fiscal deficits adversely impacting much needed investments in the social sectors of health and education. The power sector is operating with very low or no returns on the equity and no contribution to future investments from internal resources. This results in inadequate investment in additional generation capacity which is likely to further exacerbate the existing gap between power supply and demand. In 1991, IPP proposals exceeded 150,000 MW, while as of Jan 2001, just 3,500 MW of IPP power was actually operational. Even if captive market capacity addition of 1,500-2,000 MW per year is included, a total capacity addition of not more than 6,000 MW a year over the next 4-5 years is expected. This translates into US$ 6 billion of investments and several million tons of additional pollutants but would still not be close enough to meet the targeted capacity increases of 111,500 MW by 2007. 3.1.1 1. 2. 3. 4.

Supply-Side Options Existing traditional power plants Cogeneration of power Competitive market for selling power Renewable energy sources such as bio-fuels, solar etc. that are economic and environmentally acceptable 53

3.2

Demand side management

DSM is a concept in which a power utility, such as a vertically integrated SEB or an unbundled distribution company, manages the demand for power among some or all its customers to meet its current or future needs. In India, DSM can be achieved through energy efficiency, which is the reduction of kWh of energy consumption or demand load management, which is the reduction of kW of power demand or the displacement of demand to off-peak times. In the former category there are programs such as awareness generation programs, customer or vendor rebates for efficient equipment, etc. while the later includes time-of-use tariffs, interruptible tariffs, direct load control, etc. Specific type of programs depends on the utility objective: peak clipping, load shifting, strategic conservation or strategic load growth. Reductions in energy demand and construction at the end user’s premises can free up electricity generation, transmission and distribution capacity at a fraction of costs required to provide new capacity. The cost of saved energy has been estimated to be as below as 10% of the cost added capacity for some DSM measures. 3.2.1 Demand-Side Options 1. Use of high efficient motors, energy-efficient appliances, lighting, refrigeration, heating, thermal storage 2. Load management programs 3. Reduction of T&D losses 4. Tariff based on time-of-use 5. Revenue reconciliation 6. Use of available solar energy for heating and other applications 4.

Supply side management and Integrated Resource Planning

4.1 Existing traditional power plants The efficiency of existing power plants should be increased. Use of better quality of coals, new technologies, efficient motors, modern techniques for ash handling, etc. may increase efficiency of power plants and reduce environmental problems. 4.2 Competitive market for selling power Many countries have a concept of deregulating their electric power sectors. Deregulation allows competition among generators and creates market to provide economic and higher quality of supply. The needs are achieved through transmission open access (TOA). In open access system, the use of transmission system should be open and non-discriminatory. The transmission open access is the most recent concept to provide better quality of service at a lower price and to regulate the monopoly in the transmission system thereby creating market conditions. The private players should also be encouraged to take interest in the business of electric power. Transmission open access is meant by enabling third part to use the transmission network which belongs to fully or partially to another party for the transactions under the regulatory concept. Transmission open access may be an effective mean to provide reliable and economic electric supply. For power sector reform transmission open access is considered as a useful tool. To create competition in the electricity business it is required that there is an easy access to the electricity consumers. In open access mode, the generators may have direct contract with the consumers. In open access system it is required that the access to transmission should be regulated and efficient pricing methodologies should be applied. There would be more complexity in the future expansion of the transmission system. Regulatory aspects would be critical.

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To create competitive electric market in Indian scenario is a desirable feature. The present status of power supply in India is ill-conditioned. There is a need of deregulating the Indian power sector to achieve a higher quality of supply at a lower cost. The power sector reform programs have paid attention towards the unbundling of three electric companies’ viz. Genco, Transco and Disco. There is very little redundancy in the generation and the transmission. To create open access to the transmission system, there should be an encouragement to generators to increase the generation. As the generation is less than the demand in India, a need arises to open the market for new generators. The competition in the generation would help to reduce the cost of supply. 4.3 Cogeneration/captive power The cogeneration or captive generation provides the additional demand for electric power in industries. In developing countries like India the cogeneration plants serve a significant amount of power in industries. For better quality of supply at lower price and to reduce risks the most industries now have their own cogeneration/ captive power plants. 4.3.1 Cogeneration “A Cogeneration Facility is defined as one which simultaneously produces two or more forms of useful energy (e.g. electric power and steam electric pore and shaft (mechanical) power etc.).” The Ministry of Power resolution No. A-40/95-IPC-I date. 06.11.96. Cogeneration is an attractive way to meet the energy requirements of industries. Cogeneration provides greater savings to money and the environment. Cogeneration is not a new word in the industries. Many of industries in earlier days had cogeneration plants. Now again due to increasing competition in the market to offer lower price and to reduce emissions of air pollutants, the industries are going for efficient use of energy. Cogeneration offers an efficient use of energy in industries. Cogeneration facilitates them to generate their own power and thermal energy from waste. The opportunities for the industries having cogeneration are 1. 2. 3. 4. 5.

Energy at lower price Choice of fuels Improved power quality Utilization of waste Protection of the equipments from power interruptions

Industries like sugar, fertilizers, paper, food processing and textiles etc. have their cogeneration plants to produce power and heat for the various processes. The heat produced by the various processes can be utilized to generate power. The waste of the industries have used as a primary fuels. 4.3.2 Captive power production Many industries such as steel, cement, fertilizers, aluminum, paper and sugar have captive capacity to meet significant part of their electricity need. The captive power production fulfils the about 30% need of total electricity requirement of industries in India. 4.3.3 Grid connectivity In earlier days these cogeneration plants were not connected to the grid. The grid connectivity of power produced by a cogeneration plant 1. 2. 3. 4.

Plant could run in synchronous or supply power radially Amount of power to be supplied should be larger as compared to the line losses The consumer should not far away from the supplier The cost of the laying lines and interfacing system should be less so that it ensure profit to the cogenerator

55

The cogenerator sends power at 33 kV (up to 10 MW) or 132 kV (above 10 MW) voltage through transmission lines of corresponding voltage to the grid substation. The cost of low voltage lines from the cogeneration plant to the grid could be borne by the cogenerator. The cost of high voltage lines is very much so it could be divided between the cogenerator and purchaser. In sugar mills in Uttar Pradesh sell power to UPPCL and the total cost of equipments, lines, operation and maintenance is shared between them. The existing network may be utilized for transmitting power from the cogeneration plant to the grid on an agreement. Regulatory bodies have made some rules to arrange these agreements 1.

The plant shall maintain the equipments at the generating end and the maintenance of lines and the equipments at the substation shall be done by the grid substation. The cogenerator could do any work with specific approval of the buyer or regulatory commission. Installation, operation and maintenance of interconnection should be done in accordance with Electricity Grid Code.

2.

The system should be designed such that if any false or abnormal operation occurs, the cogeneration plant is isolated by circuit breaker.

3.

The plant generating set should be synchronized with the grid. The buyer would not be responsible for any fault occur to the plant due to failure of synchronizing or protective system.

4.

The power exported and imported would be measured with two set of frequency sensitive static meters. These meters shall satisfy all the technical standards of Indian Electricity Rules and the specifications of the bureau of Indian standards.

5.

The transactions of power would be done as per instruction from the Load Control Center.

4.3.4 Environmental issues with cogeneration plants Using waste as a primary fuel cogeneration offers some environmental benefits. Cogeneration uses heat and consumes less fuel. When the fuels are burned, air pollution is the severe effect to be considered. The air pollutants are mainly nitrous oxides (NOx) and sulphur dioxide (SO2). Cogeneration reduces some of the emissions of atmospheric pollutants associated with the combustion of fossil fuels such as carbon dioxide, a contributor to global warming, and sulphur dioxide which results in acid rain. National Ambient Air Quality Standards (NAAQS) has set standards to meet the environmental issues for thee cogeneration plants. Diesel generators produces much waste heat and are not able to utilize this heat. These generators are not environmentally feasible and may cause of additional air pollution. There are some special equipments required to ensure environmental regulations. 4.3.5 Cogeneration applications Cogeneration systems are applied for small as well as large industrial applications. Small cogeneration systems are compact and economical. The systems below 600kW capacity produce electricity and hot water from engine waste heat which can be utilized in some other applications. The most common uses for the heat from cogeneration power plants are steam for industrial processes, and space and water heating. They can operate during peak demand to meet the additional requirement of power. Industries consume the largest amount of power generated. They are now going for their own power production independent of grid. The reasons are:

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1. 2. 3.

The industry requires continuous power supply The supply should have quality and reliability The supply should be economically feasible

Due to the poor performance of electricity boards, frequent power cuts and high tariff the industry the applications of cogeneration and captive generation are increasing day by day. 4.4

Renewable energy sources

To meet the increasing power demand the number of power plants is also increasing. The gas emissions from these power plants contribute to air pollution a great extant. The burning of fossil fuels produces CO2 and SO2. These gases are harmful to human being as well as environment. Use of bio-fuels as a primary fuel in power plants reduces the level of pollution and also utilizes the waste from industries. These renewable sources are available in abundant in our country and reduces the dependence on another countries for petroleum. In IRP process these resource options are evaluated well. 4.4.1 Power through bio-fuels: waste management The term bio-fuels can refer to fuels for electricity and fuels for transportation. Bio-fuels such as ethanol and bio-diesel are becoming good supplement of petroleum fuels. Bio-fuels include alcohol, ether, ester and other bio-products such as soybean, rapeseed and vegetable. These fuels may be more economical and require less processing. The bio-products are now increasingly being seen as the bio-fuels of the 21st century. The biomass resources like agricultural waste, municipal solid waste, and industrial waste have been used as renewable fuels. The biomass contains high energy that has been stored through photosynthesis. That energy content remains when plants are processed into other materials such as paper and animal wastes etc. Bio-fuels are produced domestically and this helps to create opportunities for jobs and reduce our country’s trade deficit. This is very beneficial for our economy. Since the bio-fuels are made from agricultural waste it offers new options for agriculture sector. The domestic production of bio-fuels makes us less dependent on other countries to import oil. This improves the energy security of our country and the energy sector would not be much affected from the economy of the country having the resources of crude oil. The environmental issue is not severe with the use of bio-fuels as the bio-fuels produce less harmful emissions. When the production and the combustion of bio-fuels takes placem they pollute the atmosphere to little and reduce the build-up of greenhouse gases.

5.

Conclusion

The electricity planning is not easy in India. The challenge is not only to substitute investments in cost-effective reductions in electricity use for investment in power plants but also to obtain a better efficiency of existing power plants. The issues like Demand Side Management have been discussed since last many years but Supply Side issue in power system has not been given adequate attention. The types of generating units used by electric utilities, cogeneration, captive plants, environmetal issues are motivating force to engage in Integrated resource Planning. It is estimated that Integrated Resource Planning of Supply Side in power system can increase the overall efficiency of power system by 20-30% in India. Therefore there is a great need for Integrated Resource Planning in Supply Side Management.

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References : 1.

Beecher, J.A. 1995. “Integrated Resource Planning Fundamentals.” Journal American Water Works Association . 87 (6): 34-48.

2.

Berman, J.S. and D.M. Logan. 1990. “A Comprehensive Cost-Effectiveness Methodology for Integrated Least-Cost Planning,” presented at a conference of the Electric Power Research Institute held in Milwaukee, Wisconsin, May 2-4, 1990.

3.

Power to the People: Integrated Resource Planning in Developing Countries, L. Hill, Oak Ridge National Laboratory.

4.

A. S. Malik, and B. J. Cory, “Integrated resource planning with consideration of dynamic costs of thermal units”, Electric Power Systems Research (1999) pp. 123-130.

5.

Monenco Consultants & Associates. “Demand Side Management Working Paper No. 3.” Under contract to the National Energy Policy Office. Bangkok. July 1991

6.

Nadel, Steve, ‘Utility Conservation Programs’ in State of the Art of Energy Efficiency: Future Directions. Edited by Edward Vine and Drury Crawley. American Council for an EnergyEfficient Economy. Washington, DC. 1991

7.

Faruqui, A and E Haites. ‘Impact of Efficient Electricity Use and DSM Programs on United States Electricity Demand and the Environment.’ In conference proceedings from Demand Side Management and the Global Environment. Arlington, VA. April 1991

8.

Jeffrey L. Jordan, “Externalities and integrated resource planning”

58

Advance Methods to curb Voltage Instabilities in Distribution Network A. B. Bhattacharya*

A. S. Raghvendra*

A. M. Mulla*

H. T. Jadhav**

Lecturer Electrical Department

Assistant Professor Electrical Engineering Department

Sr. Lecturer Electrical Engineering Department

Sr. Lecturer Electrical Engineering Department

* Shivaji UniversityRajarambapu Institute of Technology, Rajaramnagar, Islampur, Sangli, Maharashtra: 415414 **Tatyasaheb Kore Institute of Technology Warnanagar

Abstract : To reinforce its western network, which was operated close to its stability limits, Maharashtra Electricity Regulatory Commission, India proposed the static VAR Compensator and Unified Power flow controller. The control in the system includes Automatic Voltage Regulator of the Generator. The controller of the SVC and UPFC, to coordinate the control action of these controller and prevent voltage instability resulting from their fighting against each other, two level hierarchical control Scheme using fuzzy logic has been developed and its performance was assessed via simulation. The second level of the hierarchy determines the set points of the local controllers of the AVRs, SVC, and UPFC and defines the switching sequence of the capacitor banks, the goal being to maximize the reactive margin of the western grid System. The proposed Fuzzy Scheme provides fast, Simple and effective way to stretch the stability limit of the system for double contingencies. Keywords : Static VAR Compensentor (SVC), Unified Power flow controllers (UPFC), STATCOM (Static Synchronous Compensators), Eurostag, Hierarchical Fuzzy Control, Double Contingencies, Pattern Recognition, Non linear Oscillation 1.

Introduction

The traditional mid-west service territory of Western grid hosts a collection of power plants mainly sited along the Koyna River. In the eastern and southern parts of these water channels, a backbone of long transmission lines at the 400 kV voltage levels energizes a 132-kV sub-transmission network that spans over the Tri-state and the Deccen areas located in the central Western Maharashtra region. The load in these areas consists of widely dispersed small rural communities and a fast growing industrial sector dominated by the Sugar manufacturing industry. As a result, the 132-kV network has been pushed closer to its stability limits, leaving not enough reserve margins to withstand multiple contingencies or planned equipment outages. Prior to the installation of voltage support equipment, the sub-transmission network suffered from severe voltage depressions, sometimes leading to blackouts whenever major double contingencies occurred. To reinforce the 132-kV network, MERA proposed two reinforcement plans in the area. The first proposition is of a ±125-MVAR Static Var Compensator (SVC) along with four 50-MVAR mechanically switched shunt capacitors to the 132-kV bus bars of the Koyna Station. This gives a total reactive power capability of + 325 MVAR for the installed Static Var System (SVS). The 132-kV bus-bar voltage is regulated by a control scheme providing a coordinated control of the four capacitor banks together with the two thyristor-controlled reactors (TCRs) and the two thyristor switched capacitors (TSCs) that form the SVC. The second major proposal was of installing a Unified Power Flow Controller (UPFC). The project is to be carried out in two main phases. During the first phase of the project, which was initiated in July 2000, a ±160-MVAR Static Synchronous Compensator (STATCOM) was to be connected to the 132-kV bus bars. The STATCOM's role is manifold; it provides reactive support to the Inez area, regulates the voltage at the station, and remotely switches on and off the series reactor at the Munde Station and several other capacitor banks in the neighboring stations. During the second phase of the proposed project, which was to be initiated in early 2002, a ±160-MVA Static Synchronous Series Compensator (SSSC) was to be connected to the dc terminals of the 59

STATCOM to form a ±320-MVA UPFC. In the event where the STATCOM is disconnected or a larger reactive power support is needed in the area, the SSSC can be converted into a second STATCOM thanks to the addition of a spare shunt transformer[14]. The controllers of the UPFC are able to independently control the voltage at the Munde station and the real and the reactive power flow at the installed 950 MVA, 132-kV line. As indicated in, they also regulate the voltages at the Karad, Kolhapur and Takari section by sending switching signals to the six shunt capacitor banks sited there, four of them being newly installed. While it is shown in a simple example of a twomachine system that the inclusion of an UPFC in one of the two tie-lines significantly increases the transient stability limits of the system, a comprehensive study still needs to be carried out in the area. It is stated in that it is required to optimize the setting of the UPFC controls so that the reactive reserves in the Inez area are maximized under contingencies. This optimization should account for all the interactions that may occur in the system, which comprises harmonic and control interactions. Control interactions are expected to occur between the AVRs of the generators at Koyna and Kaperkheda and the controllers of the SVC and UPFC, which also send control signals to the reactors and the ten shunt capacitor banks located in the area. Interactions of these controllers with the dynamic loads of the subsystem may also occur. If not coordinated, these controllers may fight one against the other to produce instabilities. Coordinating their actions is required to optimize the voltage stability margins in the area and improve the damping of the transient and dynamic oscillations under contingencies. 2.

Problem Formulation:

2.1 Voltage Stability To increase in the amount of power transfer on other lines.

The outcome of voltage instability is usually a progressive and uncontrollable voltage decay, which may lead to a complete voltage collapse (black out). The inability of the network to meet the reactive power demand is one of the major reasons for voltage instability[1]. Voltage instability is most likely to occur in a highly stressed network (such as the Western grid network), leading to a voltage collapse in some of its parts and load shedding in other parts.[2] 2.2 Voltage Instability Problems in 132 kV Network Regarding the Western Maharashtra area, it is a Sugar and manufacturing region characterized by many highly concentrated loads. Over the last few years, the load in this area has increased multifold, where as no new transmission lines were built. The increased load has driven the system to operate close to its stability limits, making it highly vulnerable to voltage collapse in a double contingency 60

case. This will be demonstrated in Fig 2.4. These figures display the voltage profile of the Western grid system for double contingencies, .1 As observed in that figure, all the voltages are close to 1 p.u and all the angles are small. Fig. 2.4 depicts the load profile for a double contingency applied on Line. For that case, the network is highly stressed since one observes the following: 1.

The voltages of the buses, to which UPFC, SVC, and capacitor banks are connected, remain very close to 1 p.u. while the voltages of the other buses have dropped significantly and the angles have undergone a large increase.

2.

The voltages at the nodes located in the vicinity of the fault have dropped more than the other bus voltages. Note that in all the double contingencies being tested, similar results were obtained Fig. 2.4 depicts the voltage profile of the system for double contingency. As seen, the nodal voltages pinpointed by ovals have dropped from 132 kV to a low value of about 100 kV. On the whole, the network is highly stressed and on the verge of voltage collapse.

2.3 Causes of Voltage Instabilities In a power system, several disturbances may lead to voltage instability. These disturbances span from a couple of seconds to tens of minutes. . Few of them play a major role or participate significantly in a particular incident or scenario. The system characteristic and the type of disturbance determine their roles. Induction Motor Dynamics Load/Power Transfer Increase, Generator Excitation Dynamics, Power Plant operator, Mech.Switched Capacitors/Reactors, Undervoltage load shedding, Line overload, SVC, Protective Relays 2.4 P-V Curves The curves in Figure 2-6 represent the voltages at few buses of the Western grid system, which were chosen based on their response to changes in load. They are associated with the operation of the network for different loading conditions. The curves were plotted by carrying out numerous load flow calculations on the Western grid system using the software program Eurostag. The load in the area was increased gradually while keeping the power factor constant. As seen in Fig. 2.6 , beyond the load of around 1000 MW, the voltage dropped rapidly below the accepted range of % 10 ±, and beyond a load of 1100MW, the load flow program no longer converged. This is the steady-state voltage stability limit of the network. However, the maximum power transferred through the network can be increased with shunt compensation. One of the challenges for this research was to increase the loadability of the system using the coordinated action of the UPFC, the SVC and the capacitor banks.

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3

Problem Solution

3.1

Prevention of Voltage Instability with the SVC

Voltage instability as discussed in the previous chapter is caused by the inability of the power system to meet the reactive power demand of the load. When the latter consists of induction motors, a drop in the bus voltage results in increased demand for reactive power and if the system cannot meet this demand, there will be a further decay in the voltage. This process may continue until a voltage collapse occurs. The voltage at a load bus is dependent on the magnitude of the load, the power factor, and the impedance of the line. For a given power factor, there exists a maximum power that can be transferred to the load and beyond which a voltage collapse inevitably occurs[8]. In such a appropriate control of the combined power factor of the load and that of the SVCcould help preclude a too fast drop in the bus voltages as the load power increases and thereby, push further the point of voltage collapse. It also helps increase the damping capability of the system should a perturbation occurs. 3.1.1 Modeling of SVC in Eurostag (Simulation Software) In Eurostag, a SVC is modeled and simulated as a current injector at the bus to which it is connected. The Eurostag standard library utilizes the model. The generalized block diagram of the model used is depicted in Fig. 3.5. Based on the description made by CIGRE, the model allows us to implement functions such as current and voltage measurement, regulator, blocking in case of low voltage conditions, and delay in the thyristors firing instants and smoothing of the control signal[9]. 3.2 Unified Power Flow Controller (UPFC) The UPFC is the most versatile FACTS controller with capabilities of voltage regulation, series compensation, and phase shifting. The UPFC is a member of the family of compensators and power flow controllers. The latter utilize the synchronous voltage source (SVS) concept to provide a unique comprehensive capability of transmission system control . The UPFC is able to control simultaneously or selectively all the parameters affecting power flow patterns in a transmission network, including voltage magnitudes and phases, and real and reactive powers. These basic capabilities make the UPFC the most powerful device in the present day transmission and control systems[8].

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3.3

Transmission Control Capabilities

The UPFC can fulfill the functions of reactive shunt compensation, series compensation, and phase angle regulation. Hence it can meet multiple control objectives by injecting a voltage phasor with appropriate amplitude and phase angle to the terminal voltage. The basic UPFC power flow control functions are o Voltage regulation with continuously variable in-phase/out of phase voltage[13] injection; o Line-impedance compensation or series reactive compensation by the series injected voltage. This injected voltage phasor can be kept constant over a broad range of the line current while the voltage across the compensating impedance varies with the line current; Phase-shifting control that is achieved by injecting a voltage phasor with any particular angular relation with the terminal voltage. In other words the desired phase shift can be obtained without any change in the voltage magnitude. 3.4 Modeling of UPFC in Eurostag (Simulation Software) The model is implemented such that the series action is represented by a voltage source inserted in series across the line and the shunt action is represented by a current Source injected in parallel[12]. The constraints due to the size of the converters, the dc-voltage source, and the transformer, limit (i) the phase-shift angle F and amplitude of the voltage inserted by the shunt part and (ii) the current inserted by the series part. , gives the UPFC's dynamic model as Implemented in Eurostag. The p-axis is in phase with voltage Vnet 1 and the q-axis leads the p-axis by 90 o[9].

3.5

Hierarchical Fuzzy Control

So far, we have seen various concepts associated with fuzzy logic and control. This section deals with the fuzzy control scheme that has been proposed for the control system is limited to preframed rules derived from the numerous simulations carried out for various contingency cases. In order to design a fuzzy system with a good amount of accuracy, an increase in the number of input variables to the fuzzy system results in an exponential increase in the number of rules required. [5] If we take the case of the Western grid system, 63

there would be at least 2 input variables from each bus, which are nodal voltage magnitude and phase angle. For a total of 16 buses, the number of variables would be 32 variables. Even if we take 2 fuzzy sets, the total number of rules to be framed would be 2 32 = 4294967296. The complexity of the control scheme increases with the number of variables involved; hence the need for hierarchical control. The idea behind the construction of a two-level hierarchical scheme is to make a layered structure of control where each layer takes into account a certain number of variables and gives a single variable as the output. Hence the complexity of the system reduces, and along with it, the number of rules to be framed. For the Western grid case, the output is also in the form of layers where in the higher level of the control scheme, the gains and setpoints of the UPFC and SVC are controlled as the operating point of the system evolves[13]. 3.6

Pattern Recognition

This is to identify similar sets of actions taken to control the voltage. From the numerous contingency cases that were simulated and from the knowledge that was gained about the

appropriate actions that need to be taken to cope with voltage instability, clusters can be formed using a supervised learning method. This greatly simplifies the number of cases to be considered in real time because all the steps have been predetermined. The only real-time calculation that has to be performed is to identify the cluster to which the present system state belongs. There are extremely fast algorithms available to deal with this situation. The next section gives a brief review of the basic concepts and methods of pattern recognition[6].

64

3.7 Design and Implementation of the Western Grid system in Eurostag (Simulation Software) This chapter gives the details of the modeling of various components of the Western Grid power system as implemented in Eurostag. Screen shots from the software have been included to give an idea about the implementation part of the models. It is to be noted that the data used in the entire

65

modeling of various transmission system parameters are real-time data provided by CERA. [ Appendix 1]

3.8 Simulation of the System in Eurostag 3.8.1 Steady-State Analysis For the steady-state analysis, the P-V and the Q-V curves were plotted for the system. The P-V and Q-V curves were drawn by simultaneous and gradual increase of the P and Q load at each bus in steps of 1%. Fig 6.1,6.3, 6.4 depicts the P-V and Q-V curves of the system without and with the UPFC and SVC connected respectively. In all these first by the 05CEDARC bus voltage for both P and Q load increases From Fig 6.3, 6.4, it can be observed that there is a considerable increase in the loadability limits of the system.

3.8.2 Transient Analysis The transient behavior of the system was studied for three types of scenarios. In the first scenario, the total load on the system was evenly increased by 5% at all the buses without any topological changes in the system. In the second scenario, the total load was increased by 5% and after a short interval of

66

15 seconds, a single line was opened. This was repeated sequentially for all the lines and the bus voltage profiles were recorded and investigated. The third scenario was an increase of load by 5% followed by successive opening of two lines at a time in short time intervals of 25 seconds. The sections below give details of the observations made for each of these cases.

3.8.3 Double-Contingency Cases In these series of simulation, double contingencies were simulated. First the P and Q load over the network was evenly increased by 5% followed by the opening of two lines at a time. Figs. 6.12, 6.13 displays the voltage and voltage angle plots for a double contingency case on Line 05HATFLD05BORLND and Line 05BUSSYV-05THELMA. Here, at time t = 5 seconds, the network load was increased; then at time t = 20 seconds the line between 05HATFLD and 05BORLND was opened, and finally at time t = 45 seconds, the line between 05BUSSYV and 05THELMA was disconnected. As observed, the system exhibits a voltage collapse even with the presence of the SVC and the UPFC. This was because their actions were neither coordinated nor

67

Conclusion Extensive studies of the behavior of the power system for different contingency cases revealed that this system performs well under light to medium load conditions, but is subject to instabilities and voltage collapse under heavy load conditions. This instability problem has been addressed by the fine-tuning of the UPFC and the SVC, wherein the maximum loadability of the system has been increased by a considerable value, and thus enabling the system to operate closer to its thermal limits. This is owing to the presence of FACTS devices like the UPFC and SVC, which are fast and highly effective means of controlling the voltage and power flow on the network when appropriately tunes and coordinated. Control coordination of these devices is achieved by means of a two-level hierarchical fuzzy control scheme. It serves as a centralized control that aims at damping the oscillations that may take place in the system should a single or a double contingency occur. The control scheme has increased the overall loadability of the network by a significant value as substantiated through simulations using Eurostag. By an appropriate tuning of the parameters of the FACTS devices and the fuzzy controller, an effective damping of these self-excited oscillations was achieved.

References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]

Carson W. Taylor, Power System Voltage Stability, McGraw-Hill, India. Thierry Van Sutsemand Costas Vournas, Voltage Stability of Electric Power Systems, Kluwer Academic Publishers, Boston. Central Electricity Regulatory Body , India ,for necessary real time data's as in Appendix (1). Prabha Kundur, Power System Stability and Control, McGraw-Hill, India. Li-Xin Wang, A Course in fuzzy systems and control, Prentice Hall, 1997. Timothy J. Ross, Fuzzy logic with engineering applications, McGraw-Hill, India. Daniel McNeill and Paul Freiberger, Fuzzy Logic, Simon and Schuster, Inc., New York. Narain G. Hingorani and Laszlo Gyugi, Understanding FACTS, concepts and Technology of Flexible AC Transmission Systems, IEEE press, NJ. Eurostag, Eurostag Software Release Notes, Tractebel-EDF, Release 4.1, Dec 2000. R. Mohan Mathur and Rajiv K. Varma, Thyristor - Based FACTS Controllers for Electrical Transmission systems, John Wiley & Sons, Inc. and IEEE Press. Yong Hua Song and Allan T Johns, Flexible ac transmission systems (FACTS), TJ International Ltd. IEEE Task Force on Load Representation for Dynamic Performance, "Standard Load Models 68

[13]

[14] [15] [16]

for Power Flow and Dynamic Performance Analysis", IEEE Transactions on Power Systems, Vol.10, No. 3, May 1995. IEEE Task Force on Load Representation for Dynamic Performance, "Biography on Load Models for Power Flow and Dynamic Performance Simulation", IEEE Transactions on Power Systems, Vol.10, No. 1, Feb. 1995. D. J. Hill, "Nonlinear Dynamic Load Models for Voltage Stability Studies," IEEE Transactions on Power Systems, Vol. 8, No. 1, May 1992. Ali H. Nayfeeh, Ahmad M. Harb and Char-Ming Chin, "Bifurcation's in a Power System Model", international Journal on Bifurcation and Chaos, Vol. 6, No. 3 (1996) p 497-512 L. Zadeh, "Fuzzy sets," Information and Control, vol.8, pp.338-353, 1965.

Appendix (1) [3] Type : Transmission line Sending node : 05HAIFSD ; Receiving node :05 INEZ Total line resistence : 0.01001 pu ; Line rated power : 523 MVA ; Total line reactance : 0.0623 pu ; Shunt Suspetance : 0.035 pu Type : Load Node name : 05BETSYL ; Base voltage : 132 KV Generated active power : 0 MW ; Active Load : 50 MW Active losses : 0 KW ; Shunt Capacitor : 0 MVR Initial voltage magnitude : 0.97746 ; Reactive load : 15 MVA Intial voltage angle : 35.11 deg Type : Generator Rated apparent power : 400MVA ; Rated Generated active power : 300 MW; Machine transformer resistance : 0.0036 pu; Machine transformer rating : 235 MVA ; Rated Turbine Power : 457 MW; Base voltage machine side : 345 KV ; Machine Transformer reactance : 0.22 pu. Type: Transformer Sending node: USABKRS; Receiving node :OSBSAND Resistence : 0.00046 pu ; Reactance : 0.01827 pu ; Shunt Condantance:0 pu ; Shunt Suspetance : 0 pu Transformer Rated power is : 836 MVA Transformer Ratio : 1.0125 pu The Station codes : 05HAIFSD - Karad, 05 INEZ - Munde, 05BETSYL - Load Station , 05BSAND - Khaparkheda, 05BAKPR - Koyna.

Acknowledgement : We would like to thank Mr. M.N. Prasad and Mr. K. Shankarnarayanan of Central Electric Regulatory Board for providing useful real time data otherwise this research work would not have been accomplished. 69

Consumer Indexing, Network Information Management Systems, Asset Management Anjuli Chandra, Director, Central Electricity Authority

1.0

INTRODUCTION

The power sector is undergoing the most significant large scale transformation in this era with deregulation, diversification and unbundling taking place. With the introduction of competition in Generation and Distribution, the consumer for the first time, will have a choice. The reforms undertaken by the state and the landmark provisions of the Electricity Act 2003 have made this possible. In fact in the new scenario Power Distribution has assumed great importance due to the realization that the problems faced in Indian Power sector are more due to the distribution sector than Generation or Transmission sectors. The costs are well in excess of revenues, and the gap has widened over the years. With the alarming situation of the finances of most of the electricity boards, the distribution sector needs to be focussed upon. Distribution reforms are the key to improve the electricity industry’s viability, and to achieve this, IT based technologies can play an important role. In fact, given the large numbers, geographical spread, and diversity of distribution business, IT is essential. It can help manage load, maintain quality, detect theft and tampering, help effectively manage billing and collection – all resulting in improved performance and customer satisfaction

2.0

STATUS OF DATA DOCUMENTATION IN POWER UTILITIES

Like any other business, power companies are also faced with various decisions vital to the operations, growth and management of the business. The quality of decision making and its implementation depends on the extent of data availability, its accuracy and the analysis carried out. The first step in this direction would be creation of an information system for decision making. Reliable and sufficiently detailed data is required to facilitate effective management/decision making in all activities of Distribution System. An extensive network of Transmission and Distribution facilities has been developed over the years for evacuation of power produced in the various generating stations and distributing the same to the consumers. The extent of the network and the consumers being fed from the network in the country as on 31.3.02 is as shown below : Voltages Length of lines in Ckt. Kms. HVDC 4104 400 KV 40887 230/220 KV 97238 132/110/90 KV 118180 78/66 KV 43849 33/22 KV 288226 15/11 KV 1753331 Distribution lines 3679596 Transformers Step up Step down

Capacity 408556.12 MVA 176025.52 MVA

Consumers All categories

Number 122469270

70

Number 25443 2207340

The extent of the supply system and consumer base to be managed is tremendous. The Transmission systems are well documented and planning , design and operation of these systems is being carried out on an scientific basis. It is the Sub-Transmission and Distribution systems, which require attention. As can be seen, the data requirements for Distribution system management are very voluminous. Many studies conducted in the utilities of the country have indicated that the data documentation in most of the utilities is very poor. The non-availability of accurate distribution system details, reliable load and consumption data etc. have been observed as one of the main problems in effective management of distribution systems.

2.1

Major problems confronting Distribution Companies in Data maintenance

2.1.1 Distribution of data across various sites Most utilities have their data base distributed across various sites. The graphic data of distribution systems is maintained through hand-drawn maps, sketchbooks, route cards with the JE/linesman. The facilities data is printed in text form on the land base maps or maintained in database tables using DBMS. Distribution of the data across various sites makes updation difficult. Further the data is not available in a comprehensive form at the area/zonal level for a comprehensive view / decision making. 2.1.2 Size of database, updation, maintenance and retrieval . The electric utilities operate complex networks that link the energy sources to the consumers. With the huge connected networks, number of spur lines and alternative feeds from different sources the creation, updation and management of distribution data is an Herculean task. There is an urgent need to establish an integrated database for use by various applications by adopting modern techniques.

3.0

CUSTOMER INDEXING

Every customer of the electric utility has to be brought into the books and his linkage to the distribution network recorded, to enable the utility to manage the Distribution system effectively. Customer indexing is a facility to uniquely index each customer asset based on electrical system codification and the source of supply to the particular customer. This will enable feeder/DT wise energy accounting to commence on a scientific basis, using an interface to existing billing & revenue software. The objective of consumer indexing is to relate each consumer with consumer index number (CIN). CIN will be used to keep track of the locations from where a particular consumer is fed. Supplier will be able to generate own format for index number by using the following parameters: • • • • •

Power Transformer (33 kV or 11kV) Feeder (33/11 kV) Distribution Transformer (11/0.415 kV) LT Feeder (0.415 kV) Pole Number Consumer Code

Customer data shall include the following information : • Name, Address, Consumer Number, Meter Number, Type of Meter, Type of Connection, Connected Load, Load Category, Supply from, Type of category. This number can be generated dynamically based on the consumer’s current information stored in database. The indexed customer database should be capable of : 71

• • • • •

Keep track of the location in network from where a particular customer is fed Allow changes to customer profile Handle request for new connections (Workflow) Tracking customer meters and recording meter changes, meter re-calibration etc. Tracking customers who are to be disconnected or reconnected as required by the billing system

The number of customers and their different attributes makes maintenance of customer database and its linkage to the electricity network a complex task. It is very difficult to handle this manually and in n most of the utilities computers are being used for this purpose.

4.0

NETWORK MANAGEMENT INFORMATION SYSTEMS

INFORMATION

SYSTEMS/GEOGRAPHIC

Advances in information technology have reached a stage where it has become relatively easy to build the data base through computer softwares. Initially, computers handled data only in alpha numeric form. However, with major developments in information technology and availability of graphic systems, new vistas of data and computation have opened up. AM/FM/GIS (Geographical Information Systems) are an off-shoot of this capability which can handle geographical data and associated attribute data in a single context. Automated mapping / facilities management systems utilize a combination of automated mapping functionality and facilities management database functionality to create, store, retrieve, manipulate and display variety of land base and facilities information. These systems combine facility location information with facility record information (FM) as well as provide general land base information to which facilities are referenced. A Network information / Geographic information system is a system that is designed to work with data referenced by spatial or geographic coordinates. In other words, GIS is both a data base system with specific capabilities for spatially referenced data, as well as a set of operations for working with the data. This facility enables documentation of sub-transmission-distribution network and development HT & LT network and consumer-database with detailed information availability regarding network layout i.,e. under ground route, conduits, electric cables, accrual route, poles etc. Maps are the backbone of all GIS activity. The maps are available as · Topographic maps produced by Survey of India · Geological maps produced by Geological Survey of India · Satellite imagery from National Remote Sensing agency These maps are commercially available at the District and Taluka levels and are generally reliable. However, reliable geographic maps at village level are difficult to find. Therefore creating accurate GIS at village level becomes very difficult. In this system the complete electrical network including low voltage system and customer supply points with latitude and longitudes is overlaid on maps along with associated attribute data.. Layers of information are contained in these map representations. The first layer could correspond to the distribution network coverage. The second layer could correspond to the land background containing roads, landmarks, buildings, rivers, railway crossings etc. The next layer could contain information on the equipment viz poles, conductors transformers etc. and so on.

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5.0

APPLICATION OF AM/FM/GIS IN DISTRIBUTION SYSTEM MANAGEMENT

Most of the electrical network/equipment have a geographical location and the full benefit of any improvement can be had only if the work is carried out in the geographical context. Business processes such as network planning, repair, operation and maintenance connection and reconnection have to be based around the network model. Even while doing something as relatively simple as adding a new service connection, it is vital to know that users of the system are not affected by this addition. GIS in conjunction with system analysis tools helps to do just this. AM/FM/GIS solutions can be utilized to carry out facilities management, network analysis, network planning and design and trouble call management. The success of such applications is largely dependent on capturing land base and network features in accordance with defined requirements. 5.1 Asset Management/ Facilities management Facility Management is an important area for the geographically diverse Distribution business. Keeping track of the important field equipment such as meters, transformers, CT’s and PT’s is very important. Most of the utilities do not have asset records and hence no transaction based system to allow distribution companies to optimize their operation an d maintenance activities. The scope of Facilities Management in AM/FM/GIS solutions includes asset tracking, maintenance scheduling, maintenance data compilation and correlation of maintenance data with operations and outage data to mange useful life of network facilities. By defining maintenance activities that need to be carried out for network facilities and their associated periodicity, it is possible to draw up maintenance schedules. As and when maintenance is actually carried out either by plan or due to emergency, the data can be logged in the facilities database for determining future maintenance actions. It helps in managing substation and network assets so that unplanned downtime is minimized, unscheduled maintenance is reduced, investment in inventory is decreased, parts availability is ensured, sourcing and procurement is streamlined, overall operational performance is improved and the need for new capital expenditure is decreed Further it helps increase labour productivity with increased safety and improves resource utilisation by having the right skills and the right spares at the required time and place. By recording asset identification number in the network facilities database, it is possible to locate fixed assets at site. This is especially useful at the time of retirement of assets. Moreover, assets such as meters and transformers, which undergo frequent change in locations, can be tracked and movement history compiled using the facilities database. MIS generated from the data can help identify troublesome devices, which can be assigned for maintenance or replaced altogether to prevent frequent outage in future. 5.2 Electrical Network Analysis, Planning and Design Electrical Network Analysis Engines are available, which have ready interfaces with most leading AM/ FM/GIS software and can import network data from the facilities database and carry out analysis. Using these analysis tools the following studies can be carried out: · · · · · · · · · ·

Load Flow Analysis Short Circuit Studies Network Reconfiguration Network Re-conductoring Optimal Capacitor Placement Loss estimation studies Optimal Distribution Substation Location Planning of network to meet projected load demands Study of various alternatives What if analysis

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In fact, it is possible to develop an interface between Load Flow Analysis resident in AM/FM/GIS system and SCADA system and use real-time SCADA load data for analyzing the behavior of the network at real time. By combining result of network studies with cost records and other relevant data, it is possible to determine financial viability of projects for network optimization. This provides an excellent opportunity to derive, in the short term, return on investment made in implementation of AM/FM/GIS systems. 5.3 Trouble call management Trouble call management software available with an AM/FM/GIS software relates a customer call to the relevant customer record in the Customer information system, locates the customer on the GIS and analyses the network to predict the possible faulty device, which the despatcher can use to guide crew at site. In case the crew reports that the devices is healthy, the prediction engine automatically moves upstream and locates the next possibly faulty device. In case it is necessary to dispatch another crew, after the fault is located, the software closes the initial trouble order and assigns a new trouble order to another crew. When the call is finally closed, the software records information regarding the nature and locations faulty device, the type of fault found, corrective actions taken, as well as materials issued from inventory to service the call. As the exact duration of outage along with the number of customers affected gets automatically captured, it is possible to derive reliability indices as well as cost of servicing the outage, including lost revenue. It is also possible to have an interface with SCADA system to capture information regarding outage such as tripping taking place at substations, for which trouble calls may not have been received, so that the outage database is comprehensive. 5.4 Energy Accounting and segregation of System Loss Energy Accounting and segregation of System Loss into technical and non technical loss can be carried out with information generated regarding technical loss in a network from the Load Flow Analysis and information regarding the disposition of consumers on a distribution network as captured in an AM/FM/GIS system in conjunction with the billing database . This helps eliminate inaccuracies that creep in when Energy Accounting is done using rough estimation of energy consumption of those consumers whose meters reading data does not coincide with the audit period. By relating the percentage of loss derived from Energy Accounting with the percentage of technical loss available from Load Flow Analysis, it is possible to arrive at non-technical loss and accordingly determine areas that need attention. 5.5 Commercial/ customer related activities With the voluminous customer base being catered to, by each utility, transactions have become increasingly complex, competitive and high cost. Consumer–centric operations, simplification of billing and collection processes have emerged as the need of the time. To provide customer quality service the following processes come into play : · Application processing system · Meter reading · Billing system · Collection and payment systems These activities can be integrated with AM/FM/GIS for eeffective management of these processes. Application processing system serves as the gateway through which a new consumer is inducted into the electricity distribution system. The application has to be registered, inspection of site done, assessment of work made, work order given, work executed at site, energisation of supply made and payment collected. The consumer has to be integrated into the billing meter reading and billing cycle of the utility. Further, while adding the new connection, it is vital to know that the existing users are not affected by this addition.

74

Meter reading, billing, collection and customer services have assumed significance, as they are the key milestones of revenue cycle. When the information remains distributed among various standalone systems, it is difficult to have an integrated customer information system. IT based integrated information systems provide the cornerstone for such applications. 6.0 The Road ahead Islands of information exist in the utilities for handling different jobs. A complete data/documentation system has to be put in place which is accessible to all the users for their various activities. The priorities are network & consumer documentation. What is needed is Network mapping • Mapping & documenting the electrical assets like substations, transformers, and the wires Consumer mapping • Identifying all consumers in the system • Rectifying the existing code (Service No, K No..) to make it unique • Mapping & documenting all consumers connected to the network • Updating the billing records • Linking mapped consumers to billing records Network & Consumer mapping could be started off with preparation of Single Line Diagrams with the help of appropriate software. GIS coordinates can be obtained and linked to the Single Line Diagrams at any later stage to build a complete GIS system. Softwares such as ARC/INFO, ARC/ VIEW, ERDAS, MAP INFO, EASI PACE, ERDAS etc are commercially available for building map information. Creation of land base and network facilities database is, however not a one-time exercise, as such information undergo changes over time, and Automated Mapping features in AM/FM/GIS solutions have to be used to continually update the database. The usage of AM/FM/GIS system is pretty much in the nascent stage in the power utility sector in India. Some utilities have implemented pilot projects viz Noida Power company, Calcutta Electric supply Corporation Andhra Distribution Companies, Karnataka Distribution Companies etc. The Chattisgarh State Electricity Board has planned to implement a comprehensive and Coordinated Network information system to facilitate their Business operations. TNEB has taken up GUIS based network mapping and Consumer indexing for Chennai city.

7.0

CONCLUSION

Distribution reforms have been identified as the key focus area in the power sector reforms process as maximum revenue loss is occurring in this part of the electricity sector. Controlling costs, improving efficiency and reducing down time has become essential for a utility in order to be successful in the highly competitive environment of today where private utilities/distribution companies are coming into distribution. For this, reliable and sufficiently detailed data must be available to facilitate decision making in all activities of Distribution management. With the complex, geographically diverse networks having a large number of spur lines and alternative feeds from different sources, the creation, updation and management of Data is a challenge. Huge data volumes and need for faster response to customer needs requires use of It based systems in Power distribution. AM/FM/GIS systems integrate common database operations such as query and statistical analysis with the unique visualization and geographic analysis benefits offered by maps. These abilities distinguish GIS from other information systems and make it valuable for explaining events, predicting outcomes and planning strategies for Distribution System Management. Although Creating a AM/FM/GIS system is a time consuming, resource intensive and laborious task the benefits gained in being able to relate existing facilities information to land

75

base features outscores the costs when it comes to applications such as network planning, trouble call management or facilities management. With these modern information technology tools, the power utility can become proactive rather than re-active Implementation of GIS, in the context of Distribution systems would have to be carried out in a phased manner. Most of the Distribution utilities do not have required systems and infrastructure in place. Customer management and network monitoring and maintenance should be of prime importance in the changing Business environment to take care of the increasingly discerning customer’s needs.

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Prefabricated Distribution Substation - A complete electrical equipment - (Technical choices, and IEC standard evolving)

Bernard Teissier

Yann FROMONT

Introduction The de-regulation of the electricity distribution market and the disastrous effect of power cuts forces utilities to find efficient and cost-effective solutions in order to maintain and improve the quality of electricity distribution. Utility experience shows that improving distribution reliability has to take into account the whole MV network : •

Optimise network structure Increase the number of primary substations Reduce the length of feeders Increase the number of feeders Reduce MV network structure complexity Strengthen main feeders Put ring switchgear between feeders

•

Increase network reliability : Use reliable equipment: environmental proof switchgear, prefabricated substations built and test at the factory, surge arresters etc. Put in place preventive maintenance: inspect suspect feeders, update or change equipment used at their maximum ratings, make routine inspections of the network etc. Use more and more underground cables especially in harsh environment

•

Set up monitoring and remote control equipment : Fault passage indicators; Remote terminal units and SCADA systems

The most efficient and cost effective solution to improve the reliability of the network is to implement a SCADA system to monitor and control the distribution network

Secondary distribution network The secondary distribution network is the part of the network starting at the electricity source point such as HT/MT or MT/MT substations to the low voltage network that is MT/BT substations. The structure of the secondary distribution networks in a given country or area is in part the result of the main technical features adopted for the EHV and HV systems. Other determining factors are the load, the density of consumers, the expected development, the construction costs and the expectations regarding the availability of the supply. 77

The basic secondary distribution structures are : Tree structure Open ring Spindle arrangement Double circuit Two of the main structure used are shown below :

Underground network, double circuit structure arrangement. Each MV/LV sub-station is fed from the normal supply feeder. By fitting suitable fault detectors and arranging the switches for electrical operation, the power supply, in case of a fault on the normal supply feeder, can be restored within a few seconds by automatic switching to the emergency supply feeder.

Prefabricated substation 40 years’experience MT/BT distribution substations are power supply delivery points. They are the interface between utilities and their consumers. The use of factory prefabricated substations is the most efficient way to guarantee a high level of reliability in delivering electricity to consumers AREVA T&D had designed, manufactured and marketed for more than 40 years factory prefabricated substations with the following characteristics: · Up to 40kV; · from 3m² up to 30m² (expandable to 210m²); · Concrete or Glass reinforced concrete; · Walk in, compact and underground substation. 78

Well experienced process Manufactured Equipped Tested

1

M.V. L.V.

Erection

2

Transport (Delivery time)

3

4 Operation / Maintenance

3

Increased reliability and availability Compared to built substations, prefabricated ones offer advantages well recognised today by utilities. • A single negotiating partner : whole equipment (cubicles, transformers, low voltage panel, ground circuit, etc.) are fully factory assembled according to well mastered industrial process under AREVA T&D guarantee ; • Reliability: whole MT & BT equipment fully factory tested in compliance with ISO 9001 standard. • Delivery time: planned and guaranteed, reduced erection time; no more than half a day • High quality level: better climatic and internal arc capability; better safety for operators and people who are in the surrounding area .

A large range well fitted to customer requirements; customer technical choices Requirements in urban area are not the same as in rural area. In urban area the most important constraint is the available ground area. So according to the different constraints AREVA T&D has designed a large and varied range of prefabricated substations: •

Walk in substation. With a very large floor area, it is well fitted to rural area offering easy operation especially in case of bad weather. Surfaces are from 8 to 12 m² according to the rated voltage (11 to 36 kV) and the transformer rated power (up to 630 kVA).

•

Compact substation. With a very reduced floor area it is well suited to urban area where available ground area is reduced and often expensive. AREVA T&D range is named COMPACT. Surfaces are from 3 to 6 m² with a height of 1.5 m protruding above the ground. These dimensions allow the easy installation of COMPACT substation on pavements with few disturbance and low visual impact. For all these reasons our COMPACT range is well appreciated.

•

Underground substation. This solution is the best for town centre. After erection all the area is available and there is no visual pollution.

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Compact, Large or Underground

However, as for all MV/LV transformer substations it is necessary to remove heat, so ventilation is needed. In the case of underground substation a specific calculation according to the environment is necessary.

3 Solutions Depending on the Application 2 Modules

1 Module

A truck can be driven across

A truck can be driven occasionally

1 for Transformer and LV panel 1 for RMU

1 Module Submersible

The right product for the appropriate need 4

There are various substation types according to the area where it is located and the use of this area: • • •

Underground substation « pavement » : two tanks with strengthened concrete floor which can support the weight of a fire engine if needed. Underground substation « garden » : only one tank, on which a person can walk but will not support the weight of a lorry or a car. Underground substation « liable to flooding » : fitted with a ventilating shaft, it is designed to withstand exceptional floods

Enclosure materials and their advantages The firsts prefabricated substations were built with metallic enclosure. But very quickly, solutions using concrete were used in order to improve human safety and reliability. Reliability is linked to 80

the improvement of mechanical and climatic withstand. Moreover a high level of aesthetic can be reach using concrete enclosure. The new technology of light concrete named GRC - Glass Reinforced Concrete - well known for use in buildings, has been adapted for electrical distribution in order to meet mechanical characteristics not available with concrete and offering a product 2 or 3 times lighter than concrete. This makes a product which is easy to transport and install. So the enclosure technology is chosen according to the application: •

Reinforced concrete substations. This technology is used for large substations with high mechanical withstand and where aesthetic aspect is needed.

•

Metallic substations. These kinds of substation are sensitive to heat, humidity and condensation. So they are used in areas where climatic conditions are not critical and where lightness is the most important characteristic, which is, usually the case for mining or temporary substations.

•

Substation GRC made. This technology is used for compact substation in which a high mechanical strength combined with lightness can be achieved. GRC is a watertight material with a high thermal inertia and very good condensation behaviour. So these kinds of substation are insensitive to environment.

Moreover we can offer with this technology a fully integrated solution including a concrete basement. In this case there is no civil work to do on site except to dig the hole and put in a sand foundation.

Basement Civil work to be made on site

Integrated

With the integrated basement : Maximum savings 5

Aesthetic and environment-friendly More and more environmental constraints are increasing and substations have to be well suited to the area where they will be installed. Underground substations are well fitted to their environment for the very good reason we can't see them. AREVA T&D offers a large range of substations, which can be decorated, as the same way as a house. So decorations using wood, stones, bricks and various styles of roof are available and factory made.

81

Aesthetic: A Large Choice Fully Manufactured and Tested in Factory

Same products Various results 6

International standards evolution Taking into account all those technologies of enclosure, we must not forget that the distribution substation is electric equipment after all. For this reason an IEC standard, CEI 6-1330, has been dedicated to MV/LV transformer substation. Actually it is not sufficient to test each electric switchgears individually because their integration and cabling in a very tight enclosure may modify technical characteristics and operation conditions. For these reasons prefabricated substation standards take into account : The enclosure test about environmental withstand The electric test of all electrical equipment wired and integrated in the enclosure.

1000 W/M ² 60° 40° IP23 D = à 30K -10 °

34 m/s

20 j

Type tests requested Temperature rise test Substation temperature class which lead to a derating of the transformer performance Protection index IP (against external aggressions) Arc containment Mechanical tests Ground circuit test EMC tests Tests for radiated noise are in discussion 82

The effect on the environment is reduced to a minimum (radiated noise reduced, internal arc contained etc.) and the effect of climatic conditions (storm, snow, rain etc.) are well managed. Reliability of equipment, the safety of operator and the public are optimised and guaranteed.

MV fault location The use of prefabricated substation improves significantly electricity distribution reliability, but in spite of this, faults can still occur on the network. Faults can be due to climatic conditions, cable ageing, civil work etc. In case of fault the main concern of the network manager is to : • Locate the fault • Insulate the faulty part of the network Re-power the healthy part of the network as soon as possible without creating network constraints such as feeder overloads, voltage sags, a lot of switchgear operation, etc. In order to locate the faulty part of the network very quickly and without a huge inspection and a lot of disconnections and re-powerings we should use fault passage indicator. AREVA Fault Passage Indicators are widely used in MV/LV distribution substations.

Starting an inspection from the primary substation, down the feeder, the operator can locate very easily the fault by verifying the status of the fault passage indicator lights, located on the external part of the wall of the substation. The fault is located between the last substation having a flashing light and the first substation having a switch off light. As the indicator is outside the substation – visible at 50 m in the day and 100 m by night – the operator can make a very quick and efficient inspection. The use of fault passage indicators it’s a very efficient and cost effective way to locate the faulty part of the network, but is not the only way to improve the management of the network.

Remotely controlled secondary distribution substations The use of a Supervisory Control and Data Acquisition system associated to remote controlled substations allow • in normal operation to modify the network structure in order to have the same level of load on the feeders and that in real time, To optimise voltage plan, and to reduce losses; • In case of a fault, to isolate quickly the faulty part of the network and to re-power the healthy part by re-structuring the network. The re-structuration of the network can be computer assisted using some network automation software.

83

RCX : Remote terminal unit dedicated to secondary substations Compare to RTUs found in primary substations, RTUs dedicated to secondary substations presented some specificity : • It has to be cost effective : due to the high number of secondary substations the price has to be a little part of the total price • It has to be compact : due to the cost and the availability of land the volume of secondary substation is reduced to the minimum • It has to be autonomous and maintenance free; it is able to operate cubicles Open and close even when there is no more power supply for a long time, 10 hours and more • It has to integrate specific automatic mechanism suited to manage feeder RCX-ITI is the AREVA T&D RTU specially designed to integrate the secondary distribution substations in an advanced network management system of the SCADA type. The RCX-ITI is linked to the SCADA centre through radio links or Public Switch Telephone Network (PSTN) or dedicated lines (DL) and uses open protocols such as IEC 870.5.101.

RCX-ITI is built in a very compact cabinet and integrates : • A backup power supply with battery charger with integrated battery test and batteries • A power interface to operate electrically the cubicles locally or from the SCADA centre. Switch positions are reported on the front panel and to the SCADA centre • Fault detectors, up to 4, automated so that it can open automatically the switch when the circuit breaker at the head of the feeder is open, currents phase measurement; fault passage indications and currents measurement are reported on the front panel and to the SCADA centre • A central unit managing the internal bus, the communication protocol, time stamp events memory, a serial link to plug a PC laptop for settings and alarms, a Modbus link to connect specific applications • A modem fitted for radio link and DL or PSTN • A radio and PSTN or DL interface • Digital inputs out puts Such an integrated RTU reduces installation commissioning and maintenance costs. As shown in the picture below, the RTU can be integrated into the Ring Main Unit that reduces cables and space.

84

Conclusion Electricity distribution deregulation imposed to distributors to focused on their job of distributors and give to product manufacturers tasks linked to design, erection, commissioning. Factory prefabricated substations have a lot of technical advantages as seen just before, they have also a lot of administrative management. Distributor has to buy one fully equipped product to a supplier instead of buying a lot of products: cubicles, transformer, low voltage panel, RTU, to several suppliers and managing transport, erection, tests etc. Moreover individual product test is necessary but not sufficient, the most important is to verify the good functioning of the whole package. For that reason the IEC 6-1330 standard is dedicated to ML/LV substations. This standard allows reaching and guaranteeing a high level of quality as well as for the enclosure as for the whole package. Moreover environmental withstand and impact, and safety of operator and public are taken into account. Nevertheless, as seen before, substation reliability can’t prevent faults occurs on the network due to various causes. In order to improve network management, to locate and insulate faulty parts, to re-power quickly most of the customers a SCADA system with remote controlled switchgears have to be used. Remote controlled secondary distribution substations take a large part in the improvement of electricity distribution quality

85

Application of IT in Distribution Systems for Revenue Improvement V. N. Manohar Former Director-in-Charge, Tata Consulting Engineers

INTRODUCTION 1.

2.

3.

For improving the power situation in India, the initial focus during the 1990s was on increasing generating capacity. Foreign private investors were invited to set up Independent Power Projects in India under a cost-plus regime. However, an important condition imposed on such investors was that all power generated must only be sold to the SEBs, who were clearly unable to pay. It should have been obvious that such a business model was unlikely to work. It has taken a long time for the power planners to recognize that the key to improving the performance of the power sector as a whole, lies in improving the financial health of the SEBs which, in turn, requires that first and foremost, the SEBs should recover the charges legitimately due to them for the energy supplied. The emphasis has now shifted to improving the distribution systems including privatization. Initial attempts at privatization of distribution in Orissa has had many problems. However, a more realistic approach has been adopted for the recent privatization of distribution in Delhi, and it holds promise of success. The crux of the problem is that, of the energy supplied by the SEB, only about half is billed, the difference is euphemistically termed “T&D losses”. However only a small part of these are “technical” losses, the majority being “commercial” losses caused by defective meters, inaccurate database, theft and the like. Hence, it is better to use the phrase “ATC losses” or Aggregate Technical & Commercial losses.

EXTENT OF THE PROBLEM 4.

5.

6.

The ATC loss is the difference between the total energy supplied and the total energy billed. In a recent study carried out in an SEB sub-division, the ATC losses were found to be 50.19% when the SEB sub-division was regularly indicating the losses as 11–12%. In another subdivision the reported ATC losses were 7% but were found to be 34% on a field survey. The agricultural load, which is not metered, is routinely shown at a much higher value, so that the ATC loss can be shown to be much lower than it actually is. A similar state of affairs obtains in most SEB divisions. Such field surveys have shown that the SEB management reporting system does not report the losses correctly. It is now generally accepted that, apart from EHV supply, the SEBs are billing for only 5060% of the total power which they supply; the balance 40-50% is the ATC loss. This loss was usually attributed to unmetered agricultural loads. However recent field evaluation has found this to be incorrect and it has now been established that the ATC loss is largely due to deficiencies in the meters and meter reading systems and large-scale theft of electricity. This has been confirmed in the case of Delhi where there is hardly any rural or agricultural load, and the ATC losses are around 50%. A realistic estimate puts the cost of such leakage for the whole country at well over Rs 30,000 crores per annum. In fact the CMD of the Power Finance Corporation has publicly stated that “The Problem No 1 in the State power sector is not tariff but large scale theft.”

FINANCIAL IMPACT OF ATC LOSSES 7.

The financial impact of ATC losses is on both the consumer and the SEB. The consumer has to pay a higher tariff than is necessary and the SEB’s financial health is so seriously affected that it cannot raise the necessary resources to upgrade and expand its system. This can be illustrated by taking the case of Delhi, where there is hardly any rural or agricultural load. The data provided in the public notice recently issued by the Delhi Electricity Regulatory 86

Commission (DERC) indicates that the 3 distribution companies have projected an ATC loss of 44.35% for the year 2004-05 and a combined deficit of Rs 1,582 crores. This deficit will have to be made up partly by a tariff increase and partly by a subsidy from the Delhi Government. If however, the ATC losses were reduced to 15% (which is still high for a metro city), the discoms would have a surplus that would allow a reduction in the tariff, as well as a sizeable profit for themselves. This is illustrated in the Table given below. 3 Delhi Discoms Combined estimate for 2004-05 Energy Input Estimated ATC Loss Estimated energy sold Average retail tariff Estimated revenue realization Aggregate revenue requirement Estimated revenue gap

18,555 MU 44.35% or 8,230 MU 55.65% or 10,325 MU Rs 3.67/unit Rs 3,787 crores Rs 5,369 crores Rs 1,582 crores

If ATC losses are reduced to 15% Energy sold would be i.e. additional sale of Extra revenue would be

15,772 MU 5,447 MU Rs 1,999 crores

This additional revenue will cover the estimated revenue gap and leave an additional surplus of Rs 417 crores for the discoms. This will permit a reduction of the existing tariff.

MAIN CAUSES 8.

The main reasons for this state of affairs are :

a. b. c. d. e. f. g. h.

Defective meters; No meter for many consumers; Meter tampering, usually with the connivance of the SEB staff; Non-reading or incorrect reading of meters; Theft and unauthorized or unrecorded connections; Incomplete and inadequate consumer database; No system which can provide dependable data on the leakages; Lack of management attention.

9.

The present system of meter installation, meter reading, meter checking, billing and revenue collection results in voluminous paperwork, and it is almost impossible to have any effective checks. A further difficulty is that human beings are involved at every stage of the process and they are subject to pressures and succumb to temptation.

10.

What is necessary is a system that will provide unbiased information of the location and magnitude of the theft or leakage on a continuing basis, remove the scope for any individual to manipulate the data, have a transparent and non-discretionary mechanism in place for taking corrective action, and have a robust foolproof and decentralized system which is centrally monitored. This can only be achieved by using the tools of information technology to the maximum extent in the meter reading, billing and monitoring area. These changes can be introduced in a manner that results are achieved without disrupting the present system of working.

87

PRESENT SYSTEM OF METER READING 11

The present system of meter reading involves human beings at every step of the process, from reading the meter, entering the reading in the record books, keying in the data, and in some cases even calculating the amount to be billed. A typical system is shown diagrammatically in Fig 1. It is obvious that errors, genuine or otherwise, can creep in at every step of the process.

PROPOSED SYSTEM 12

. · · · ·

A modified system is proposed which will overcome the various drawbacks of the present system of working, using Information Technology to remove any scope for an individual to manipulate the data. The starting point for any dependable system is to have a properly functioning meter at the consumer’s premises that accurately records energy consumption, To ensure this it is necessary to have a comprehensive program of meter checking, calibration and replacement of defective meters. The following steps should be part of such a program: Increase the capacity and update the capability of the meter repair, testing and calibrating laboratory, with adequate specialized kits for meter testing at site with printout facility; Have adequate spare meters, preferably of the electronic tamperproof type, so that any meter found defective is replaced on the spot; Have a checking squad for random verification of the routine work done; Have a database of the meters with information of their type, status, location, CT and PT ratios used, multiplying factors, date of testing etc, Provide a rigid system under which no meter can be removed, tested, or replaced without a computer generated authorization, which can only be produced when the relevant data is added to the meter database and specified conditions are met.

13

For HT meter reading, new meters should be installed with remote reading facility and a communication link to the host computer at the substation. With this the meters can be automatically read according to a preset schedule, or on demand. With a direct communication link, it will be possible to access the meter from the main substation at any time, and in case of doubt, some of the consumers can be put on a watch list. Further, the operator will immediately get an alert signal whenever the meter is tampered, and he can alert the checking squad for quick action.

14

For LT meter reading, a remote meter reading arrangement with a telecommunication link as proposed for HT meters will not be cost effective. It is adequate to have a handheld computerized data–logger (CDL), into which the meter reader can directly key in the meter reading at the consumer’s premises. Special software should be installed in the CDL to eliminate any scope for tampering. The consumer data for the route of each meter reader would be downloaded from the host computer at the start of the round. However, the meter reader will not have access to the earlier meter reading although it is in the CDL. With the help of the consumer data already loaded in it, the CDL will verify that the reading is reasonable. If there is problem, CDL will give a signal and the meter reader can inspect the location and note the type of problem. With this arrangement it will not be possible for the meter reader or other staff to manipulate the readings. The data would be uploaded on to the host computer at the end of the day and the problems reported would be passed on to a checking squad for investigation the next day.

15

Trend analysis, comparison with earlier consumption patterns, etc. would be built into the host computer program to spot aberrations indicating meter tampering, illegal use of power etc. and this would be printed out for investigation by a separate team. Needless to say the computer generated list of consumers to be looked into by the checking squad and the investigating team should also contain a few consumers where there are no problems, so 88

that checking is done without any preconceived ideas. The results obtained by the checking squad would be directly fed to the host computer for comparison with earlier readings so than human intervention is avoided. 16

When there are discrepancies, the program will decide, based on predetermined criteria, whether an “assessed” bill should be prepared pending investigation. The program will thus have a diagnostic feature. Based on such assessment, the metering data will be passed on to the normal billing agency of the utility to print out the bills based on the prevailing tariff. The arrangement is shown diagrammatically in Fig 2.

17

With the data of the meter readings and later checked readings by the checking squad available on a continuous basis, the program will also be able to provide an evaluation of the meter reader performance.

ENERGY AUDIT 18

A dependable regular energy audit of the total energy supplied and its utilization is the only means to evaluate the energy leakages in the system irrespective of the nature of he leakage. With all meter readings available in the substation computer, it is possible for it to carry out an energy audit automatically without further inputs.

19

For the HT system the energy supplied to each feeder would be compared with the total energy billed to consumers and to the LT system through distribution transformer centers (DTCs). Where considered necessary, a few additional meters can be installed in the feeder to further subdivide the feeder into zones for a zone-wise energy audit. With all meter readings available in the substation computer an automatic energy audit of the HT system would be carried out every 24 hours or on demand. For the LT distribution, such energy audit can be carried out at each meter reading cycle by comparing the total energy fed to each DTC with the total energy billed to consumers supplied by the DTC.

20

It is possible to estimate the total “technical” losses in the distribution system from the distribution system information and load data. With information of the total energy supplied, total amount billed and the estimated “technical” losses, the unaccounted energy or “commercial losses” for each zone will be known. The intelligence built into the computer program will help in indicating likely areas where meter tampering or other leakages are taking place. This information will assist the checking squad to inspect and take action in the field.

21

The program would aim for continuous improvement of the meter reading, billing and revenue collection system on the one hand, and reduction of distribution losses, and different types of energy leakages on the other. The feedback information from the IT system would demonstrate that the situation is improving from month to month, so as to give confidence that the problem can be brought under control.

TRAINING 22

For successful implementation of any IT system, manpower training to make the personnel familiar with the system, as well as to improve motivation and performance is essential. This has to be a major exercise. Persons with only a school education can be trained to be very proficient in data entry and other aspect of using computer systems, and that they welcome the opportunity for such training.

23

Apart from this, it is necessary for the whole organization to be oriented to take advantage of new techniques. A study of the introduction of IT systems in Indian organizations has found 89

that other managerial inputs such as management commitment, proper processes and procedures, appropriate policy framework and developing the right attitude in staff, is essential for the new IT system to be effective in producing the desired results. Training at higher levels is also necessary, as the whole methodology of working will change, and the speed with which action can be taken with information instantly available will require persons to get used to a different method of working. This change in the working style should be supported as a priority, so that everyone feels quite familiar with the new IT tools and is able to take full advantage of the capability that it offers. 24

Another aspect of training is to ensure that the change of work profile does not render anyone redundant. Those whose job function changes should be retrained to take on other jobs which this exercise will throw up.

CONCLUSION 25

The application of Information Technology allows dependable information in a usable form to be available at the touch of a button, and in a transparent manner not subject to any subjective influence. Further, the proposed system will be paperless removing scope for manipulation. It will provide automatic energy audit and be able to give an indication of the location of possible leakages, thus pinpointing the problem areas. This will help to direct the field staff to the area where energy leakages, including theft, are taking place and makes for effective remedial action. It is also possible for the month-to-month status to be available for all to see throughout the organization. With many checks and balances built into the system, it will streamline the functioning of the organization and also make the results of corrective action visible. All this will directly lead to increased revenue from the distribution system.

26

The problem of leakages and theft of electric energy results in colossal losses to the utilities and hence a major effort that can help to reduce these losses is very urgently needed. It has been demonstrated in many areas of activity, that a properly designed and implemented IT system can reduce errors, avoid manipulations of data and eliminate leakages of various types, leading to revenue improvement. It is high time the electric power sector took recourse to such methods for which the necessary technology and application capability is available. The costs of theft are mind-boggling. Even if the theft and other leakages are not eliminated, but reduced to half their present value, an annual increase of Rs.15,000 crores in revenue can be achieved!

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SESSION – 3 Customer Services • Automation : Scada, Information Links, Universal Communication Architecture, On– line Data Transmission and Retrieval • Utility – Customer Interface: Trouble Call Management, Call-Center Operation and Complaints Redressal • Role of IT and Communication Protocol in Consumer Services • Metering, Billing, Revenue Realisation & Resource Mobilisation • Convergence of Power & Telecommunication Chairman : Sh. J. P. Chalsani, Director, Reliance Energy, Mumbai Key Note Speakers : i)

Sh. V K Parashar, Executive Director, Power Grid Corporation of India Limited “Automation : Scada, Information Links, Universal Communication Architecture, On–line Data Transmission and Retrieval”

ii)*

Sh. C Ram Mohan Rao, Director (HRD, P&MM), Andhra Pradesh Central Power Distribution Co. Ltd. (APCPDCL) “Utility – Customer Interface : Trouble Call Management, Call-Center Operation and Complaints Redressal”

iii)

Sh. Akhil Pandey, Head of the Group– IT, North Delhi Power Limited “Role of IT and Communication Protocol in Consumer Services”

iv)

Dr. Prem Kumar Kalra, Dean RPG, IIT Kanpur “Convergence of Power & Telecommunication”

Additional Papers included in Binders : 1.* “Data Communication Architecture using IEC61850 Protocol for Substation Automation” by Sh. R. P. Gupta, Dept. Electrical Engineering, IIT Kanpur 2.*

“Looking Ahead in Power Distribution Business” by Sh. V.N. Manohar

3.*

“Supervisory Control And Data Acquisition (SCADA) Laboratory for Research & Training in Distribution Automation” by Ms. Mini S. Thomas, Sh. Parmod Kumar

4.*

“Communication Infrastructure in CESC Ltd for Automation of Distribution Management (Existing Practice & Emerging Prospects)” by Sh. Joy Bhattacharya, Dy. Manager Testing Department & Sh. Subir Datta, Sr. Engineer, Testing Department

* Papers received by the time of compilation

Remote operation of Bhiwadi S/S from Ballabhgarh S/S

Vikas Saxena

R. P. Sasmal

K. Rathore

Rajiv Pharlia

POWERGRID CORPORATION OF INDIA LIMITED

Preamble : POWERGRID, the central transmission utility (CTU) of the country is one of the largest transmission utilities in the world operating about 46,245 circuit Kms of transmission lines with 79 Substations across the nation having transformation capacity of 44,836 MVA. The number of substations and transformation will grow by leaps and bounds in the coming years and so will be the manpower and overhead cost required to operate & maintain these substations. To minimize manpower requirement, POWERGRID conceived and implemented the scheme for remote operation of substations from single substation. POWERGRID selected a pilot project to remotely operate Bhiwadi 400/220KV S/S (Rajasthan) from Ballabhgarh 400/220KV S/S control room (Haryana) which is at a distance of about 80Kms from Ballabhgarh. This is a maiden project of its kind in Indian power sector where an EHV S/S is considered for remote operation. This project has been commissioned on 30th Nov, 2003 and since then it is in regular operation. Initially, the operation of Bhiwadi S/S is envisaged from both locations and subsequently the operating staff from Bhiwadi S/S shall be withdrawn within six months in a phased manner. Considering the success of this project, POWERGRID has taken up the numerous other substations for remote operation.

BALLABHGARH S/S BHIWADI S/S

Overview of the Scheme : 400/220KV Bhiwadi S/S is a newly built S/S of POWERGRID equipped with conventional equipments such as Transformers, Circuit breakers, isolators, Earth switches, CTs, CVTs, PLCC, C&R Panels for control, protection and monitoring of substation equipment & transmission lines. This Substation is also provided with an RTU under ULDC scheme for monitoring of parameters at NRLDC for grid management. 400 & 220KV single line diagram of Bhiwadi substation are shown in Fig-1. The scheme is aimed to remotely control & monitor the state of devices, protection alarms and power system parameters (P, Q, V, I, F etc) of Bhiwadi S/S with automatic logging and archiving features. 92

Fig 1 -Single Line diagrams of Bhiwadi S/S The scheme comprises of the following major components: • Computer based Supervisory Control & Data Acquisition (SCADA) system • Remote Terminal Unit (RTU) for interface of data acquisition & control • Reliable communication links (PLCC & FO) for data exchange between RTU & SCADA system. • Adaptation work at Substation for interface of C&R, LT power supply, Fire fighting systems • Time synchronization of computer system and RTU using GPS interface. • Remote acquisition of Disturbance Recorder data through PLCC link using DR PC at remote end • Remote acquisition of Event logger data through PLCC link using EL PC at remote end. The computer based SCADA system has been placed at Ballabhgarh substation control room referred as control centre. The system configuration is shown in fig-2. SCADA system provides a virtual environment of conventional substation to the operator by way of convenient user interfaces for control & monitoring of a distant substation.

93

FIG 2 - SCHEMATIC OF REMOTE OPERATION OF BHIWADI S/S The PC based SCADA server uses E-terra control SCADA application software for remote control & monitoring. The SCADA server communicates with S900 RTU over dual communication links at 600bps to acquire data & exercise control on controllable devices at Bhiwadi S/S. The S900 RTU also communicates with second master i.e. NRLDC, Delhi over dual communication links at 300bps under ULDC project for grid management. The communication media for primary channel is PLCC and secondary channel is combination of PLCC & fibre optic (FO) as indicated in the fig 2. The IEC 60870-5-101 communication protocol has been used between the RTU & SCADA server. The SCADA system at Ballabhgarh S/S receives real time analog & status data of Bhiwadi s/s. The shift operator monitors the real time power system data on 21" dual CRT screens and takes corrective actions using full graphics (FG) user friendly displays & advanced User Interaction techniques such as alarms, events, Sequence Of Events with 1ms resolution, trends, summary views, device tagging, panning & zooming etc. Operator can issue supervisory control commands to circuit breaker & motorized isolators through a fail safe & secured mechanism using IEC protocol in select check before execute & operate ( SBO) sequence. The operator can also raise/lower the transformer taps (OLTC). Accept/ reset of alarm annunciation is performed by remote operator for conventional control panels provided locally at Bhiwadi s/s. The system also facilitates the storage & retrieval of historical data in order to perform analysis using available FG tools. The shift operator can also generate daily, weekly, monthly reports using the report generation tools.

94

The analog data is updated in SCADA system periodically with maximum update time of 15sec. Analog data is also updated by exception to take care faster update in case major changes during tripping. All status data are acquired by exception with change reported within 4sec. Integrity scan for all status data. is also performed at every 10 minutes periodicity. The time synch feature has been provided to synchronize RTU from SCADA system using IEC protocol. The SCADA system offers scalability to cater to the future expansion in terms of I/O points by way of addition of I/O hardware for the RTU only. The same software can be used with modifications in the database & displays. The system uses open protocol interface i.e IEC 60870-5-101 to reduce complexities involved in integration. There is no requirement of such ICCP & LAN interface as the adopted scheme is a simple architecture where a SCADA system is directly connected to RTU over FO & PLCC communication medium. However, system can be augmented for integrating additional hardware such as servers, operator workstations etc over LAN interface in case there is a need in future. Similarly, new control centres can be integrated using ICCP interface in future if such need arises. The system is capable to meet the future enhanced requirement & need not be scrapped and thus investments made today will not go as a waste.

DATA ACQUISITION : The following analog and status data is being acquired and controls are exercised under the scheme as given in the table 1. Bay name 400KV B/ bars

Analog measurement Single Status (SS) V (RY, YB) and F of Protn alarms both busbars 400KV side of ICTs I (R,Y,B), P, Q, Tap, WT Protn alarms

400KV lines

V, I (R,Y,B), P, Q

220KV B/ bars

Protn alarms

Double Status (DS) Control command

CB, Isolator, earth switches CB, Isolator, earth switches

V (RY, YB) of both bus bars, F of one bus 220KV side of ICTs I (R,Y,B), P, Q

Protn alarms

CB, Isolator, earth switches

220KV lines

V, I (R,Y,B), P, Q

Protn alarms

CB, Isolator, earth switches

220KV B/C

I (R,Y,B)

Protn alarms

CB, Isolator,

220KV Transfer Bus coupler (TBC)

I (R,Y,B)

Protn alarms

CB, Isolator,x Bus coupler (TBC)

CB (open, sync close, DLC), Isolator (Open, close), OLTC raise/lower CB ( open , sync close, DLC), Isolator (Open, close)

Protn alarms

Battery charger current Charger panel alarms of charger1 & 2 of 48VDC, 220VDC system Fire fighting system F/F system alarms LT supply LT panel alarms Miscellaneous L/R switches Alarm accept /reset

CB ( open , sync close, DLC), Isolator (Open, close) CB ( open , sync close, DLC), Isolator (Open, close) CB ( open , sync close, DLC), Isolator (Open, close) CB ( open , sync close, DLC), Isolator (Open, close)

DC system

TABLE 1 -DATA ACQUISITION PRINCIPLE 95

Alarm accept /reset

SCADA software E-terra control software is the heart of SCADA system working on Windows 2000 environment. Salient features of this SCADA software are: Data acquisition & processing : The function performs acquisition of data from RTU located in Bhiwadi S/S through Communication Front End (CFE) reader application and processes the raw data received from RTU for SCADA application. It performs the following tasks. •

• • • • •

Schedules periodic scanning of the RTU for acquisition of analog data to achieve update time of 15Sec and integrity scan of all status points at every 10minutes. It also scans data by exception for status data on change of the state and analog data if it changes beyond the defined threshold limit. Performs all data processing such as dead band, reasonability check, quality check etc. Schedules exploratory scan for user guided requests and for the failed communication links/RTU. Storage and retrieval of hourly communication statistics. Handles the IEC 60870-5-101 protocol mechanism for serving the SCADA server as master and RTU as slave. Provides user interface to browse the communication model and to view the current raw values of measurements.

Supervisory control : The SCADA system executes supervisory control command in failsafe mode by using the select check before operate (SBO) sequence. The control of devices includes: • • • • •

Opening of Circuit breakers Closing of circuit breakers in check synchronising & Dead Line Charging (DLC) modes. Opening & closing of isolators On Load Tap changing of Transformers Accept/ reset of alarms

SOE recording : The state change of the devices is recorded with time stamping with an accuracy of 1ms. This information is recorded in chronological order and is very useful for analysis during trippings. Information Storage & Retrieval (ISR) The E-terra control application enables collection and storage of real time analog and status data acquired from RTU. It can also perform calculation on real time and store the same. The real time data is stored in historical files at RTU scan rate. The stored data can be transformed in text format (csv files). The data from historical files can be easily viewed for analysis by operator for the selected time period at any periodicity (other than RTU scan rate) through various UI techniques such as charts, graphs, MS office applications etc Time synchronization : The time synchronization of SCADA server is done from GPS system available at Ballabhgarh control room using IRIG-B interface. Presently, RTU time synchronization is being performed from 96

NRLDC, Delhi GPS system procured under ULDC scheme. However, the SCADA software at Ballabhgarh can also be used for time synchronization of RTU using IEC protocol. Graphical User Interfaces : E-terra control application uses display viewer application to facilitate user interaction techniques with Full Graphics Displays (FG). The Full Graphics displays are built using display builder application. For ease of the operator the display of the S/S control panels are built in the same way and manner as appearing on the conventional control panels. All operations such as control, monitoring, device tagging, alarm accept/reset can be performed using these displays. The advanced navigation techniques such as panning/zooming, manual data entry, switching over the displays, scan inhibit /enable etc can be used for speedy and effective navigation by the user. The followings are the of FG displays build for this project : • •

•

•

•

User Login display To provide access to SCADA system through login by the authorized users Home Display After successful user login, Home display appears. This display lists all the displays available and provides direct access to them by a click of mouse. Network diagram To provide overall status of 400/220KV S/S at a glance a network diagram has been prepared. Single Line diagram (SLD) Separate SLD display has been prepared for each voltage level to have more clarity. These displays are replica of 400KV & 220KV switchyard. SLD displays indicate analog measurands & status of all power system devices. SLD displays also provide control buttons to issue supervisory control commands to all controllable devices. Control panel displays These displays are replica of substation control panels with real-time analog & status data mapped on it and provide button to exercise supervisory control actions on controllable devices. The display also provides annunciation facia to alarm operator in the similar fashion to which operator was acquainted with conventional control panels including accept/reset of alarms. The typical FG control panel displays is shown in Fig 3

97

Fig 3 - Full graphics control panel displays 98

♦

Alarm displays • This display provides listing of alarms of all urgencies and categories with time of occurrence viz. trip, non trip ,limit violation, SCADA related alarms. The display highlight alarm condition using a combination of colour ,intensity and blinking feature. An operator can accept /reset alarm individually or collectively.

♦

Event displays • This lists all events which do not require any user action and considered to be an normal event.

♦

Utility display • The display provides access to common utilities such as report generation, graphical & tabular trending, tag summary displays, hard copy printing etc.

♦

Help display • The display provides on line help to the operator about navigation & user interaction techniques.

SCADA database The SCADA database is a MS foundation class object oriented design. The object oriented design invokes the faster access of data, easy & reliable maintainability of database. All objects namely station, equipment, measurement, control etc. can be copied , cut, pasted , deleted moved ,renamed, dragged ,dropped by using the familiar windows utilities.The real time data is maintained with these objects and when any data is needed, it is obtained from resident object through method call.

AUGMENTATION OF EXISTING SYSTEM The remote operation scheme was planned on existing running station, site adaptation and augmentation were required for implementation of the scheme.

RTU/SIC augmentation The S900 RTU was provided at Bhiwadi S/S under Northern Region Unified Load Despatch & Communication scheme (NR- ULDC). S900 RTU supports reporting to different masters, the concept for using the same RTU with augmentation was conceived and implemented for remote operation of Bhiwadi S/S to optimize the cost. Under ULDC scheme, the RTU was equipped for limited data acquisition as required for grid management by NRLDC. For remote operation of a substation a large number of data points are required. The existing S900 RTU was augmented to meet this enhanced requirement. The existing dual output transducers available on the control panels were used to acquire analog data.

C&R PANELS augmentation The RTU interface to the field devices such that Circuit breaker, isolator, OLTC. Protection relays etc. is provided through interface components viz. contact multiplying relay (CMRs), transducers, Heavy duty closing & tripping relays, check synchronising relay, L/R switch etc. The C&R panel was augmented to house these components in line with the enhanced I/O requirement for remote operation of Bhiwadi S/S.

99

LT Panels augmentation The existing LT supply panel at Bhiwadi S/S was augmented to implement failsafe change over from one source to other source on LT supply failure of one or other source. The remote monitoring of battery charger current through suitable transducers is also implemented. Remote monitoring of fire fighting system alarms was implemented by augmenting annunciation panel. All these inputs are wired to RTU for monitoring through SCADA system.

Cost Benefit analysis & benefits The remote operation scheme would reduce the requirement of shift operation staff at Bhiwadi substation. However, maintenance staff comprises of 2 executives, 2 supervisor and 2 workmen shall continue to look after the routine and preventive maintenance. The reduction in manpower will be done in phased manner as indicated below. The cost of project will be paid back in less than 2 years.

Besides the saving in the manpower expenditures, there are several other benefits from the scheme as mentioned below: • • • • • • • • •

Real time data availability and its recording at RTU scan rate. Historical data availability for post disturbance analysis Portability of historical data in electronic media. FG user interface offers addition of user friendly displays. Processing of alarms is not limited to control panel alarms. Report generation for MIS purpose. More efficient operational management In future more substations can be operated from single S/S by the same operating staff. Available PLCC communication facilities are adequate for remote operation scheme.

Conclusion : Considering the growth in the Indian power sector, a large number of trained manpower is required to operate & maintain the increasing number of substations. The remote operation of the substation is the need of the hour. In view of the success of this project and low pay back period, POWERGRID is taking up such more schemes for implementation in near future. The case study demonstrates that automation can be implemented with a small investment utilizing the existing resources and the same can be integrated with other function of the scheme also in future provided the consideration is given to various design aspects of the SCADA. 100

Utility – Customer Interface Trouble Call Management/ Call Centers and Complaint redressal C. Ram Mohan Rao Director–HR & Commercial, APCPDCL

Agenda • • • • • • • •

Objectives and Goals of Reforms Customer expectation levels and Reforms Comprehensive survey and customers meet. Citizens Charter Initiatives taken up by Utilities in AP. Results of various initiatives. Benefit to Customers due to various initiatives Conclusions and way forward.

Customer expectation levels and reforms The objectives set for Power Sector Reform Programme is to create the conditions for sustainable development by promoting : • • • •

Competition Efficiency Transparency Attraction of private capital

The goals of reform are to ensure that : • •

Electric power is supplied under the most efficient conditions in terms of cost and quality to support economic development The power sector ceases to be a burden on the State’s budget and eventually becomes a source of revenue for the Treasury.

Ultimate goal of Reforms is however to improve the Quality of service to the Customer ,not only in terms of cost,reliability and availability of Supply but also in improving service in each and every transaction with the customer.

Customer expectation levels and reforms •

As the Customer is exposed to the global economies as well as to the improved service levels in many other sectors such as banking, insurance, telecommunication, etc touching upon his daily life, the expectation levels from the power sector are also high.

•

Reforms in the Power sector have definitely had a positive impact on the Customer service levels and the combined efforts of the Utilities and Regulators in this regard, has started showing some results.

•

Yet there is still a long way to go before attaining any satisfactory levels in customer service in the context of the power sector.

101

Quality of Service – Areas

Commercial Quality and Customer Service Issues

Electricity Supply Service

Power Quality/Reliability

Technical / Voltage Quality and other parameters

• Publishing Service level Standards. • Effectiveness in Complaints handling • Responding to customer queries about Supply, metering, billing & payments • Effectiveness in release of new services • Establishment of Consumer Call Centers and Service Centers • Customer etiquette & communication with customers • Better power procurement planning/practices

• Systematic & planned supply interruptions • Preventive maintenance practices & Quality in infrastructure creation • Interruptions and Breakdowns time and frequency reduction

• • • • •

Maintaining Voltage limits as per Standards Maintaining Frequency limits as per Standards Elimination/minimising Harmonics/Flicker Correction of imbalance in Voltages Adherence to Safety Standards

Comprehensive survey and consumers meet •

•

•

After the initiation of Power Sector Reforms in AP, a comprehensive survey was taken up in the year 1999/ 2000 through an external professional Market survey agency to understand the requirements, perceptions and the existing service levels of the Customers. In the year 2001, a Consumers meet was organised by the Utilities at each of the Village, Mandal and Municipality where the utility interacted directly with the Consumers in order to understand their issues and thereby obtained detailed and exhaustive feedback. Based on the Survey and the Consumers’ Meet, the Utilities have devised various initiatives to improve the customer service levels and thereby increase customer satisfaction levels.

Consumer service Issues –Initiatives Matrix

102

Citizens Charter •

•

•

The AP Power Distribution Companies have released the Citizens’ Charter in 2002 wherein they publicly provided a service assurance to the customers, who pay their bills regularly, for power and utility services from the companies. This Charter obtained the approval of the Regulatory Commission. The Discoms through the Citizens Charter are striving hard to ensure that the service assurances prescribed or surpassed The key highlights of Citizens’ Charter have been widely publicised across all offices of the Companies:

Citizens charter-Service standards in AP Citizens Charter in AP has following Standards and service levels.

Highlights of Consumer service initiatives taken up in AP • • • • • • • • •

Establishment of Customer service centres and calls centres at all the Towns & District headquarters. Consumer grievance cells in all Operation circles and divisions. Monitoring of interruptions and breakdowns on a 24hours basis and taking appropriate action Installation of HVDS (high Voltage Distribution System) in critical locations to reduce loss and improve voltages. Separate HT cells in all operation circles to promptly redress grievances of HT consumers Spot billing introduced for all the customers across the state since July 2002. Multiple payment options and payment through e-seva centers in Hyderabad & other towns Vidyut Adalats conducted at Mandal Level to resolve and rectify issues relating to wrong billing and other commercial complaints being held on every Monday. Industrial feeders separated to provide reliable, interruption free supply to industrial consumers. 103

• •

• • •

Substation wise meetings with Farmers to resolve Power Supply related issues Providing single-phase supply on rural feeders. (In CPDCL Identified 1387 predominantly Agl feeders and completed 1300 by utilising 18358 Nos. single phase DTRs) Laying of AB cable in theft prone areas (In CPDCL Identified 1657 villages and completed 1322) Conversion of 11KV feeders to HVDS in rural districts by providing small capacity three phase and Single phase DTRs 330 Nos. Industrial feeders in CPDCL separated to provide reliable supply (In FY 2003 identified 64 Nos 11KV feeders and completed 53Nos)

Establishment of Call Centres Call centres have been established in all the Towns & District Head Quarters, which have the following features. • • • • •

Operation of call centres has been entirely outsourced to have the independence in operation and monitoring. Proven Software has been installed and tracking and monitoring is systematically implemented. Common number (1912) in the Towns and Urban areas in a District for the convenience of the customers. Responsible officer posted at the call centre from the Distribution Company to oversee the complaint resolving process. Compliance monitoring with respect to the Citizens charter standards done on a daily basis and appropriate action taken in case of deviations.

Establishment of Customer Service Centers In order to provide a better and quick services to the consumers the Utilities have established customer service centers at subdivision level. CSC takes care of the following items. • Releasing new connections (other than industrial) . • All types of customer complaints / representations will be received acknowledged and redressed within the stipulated time period as per citizens charter. • In charge of CSC will have the stock of meters for new connections • In charge of CSC is authorised to collect all the charges by way of DD for new connections.

104

Customer Service Centers

All the CSC have Web enabled for better access and control

105

Consumer Complaints in Customer Service Centers in Hyderabad & Other Subdivisions in Districts of CPDCL

Common complaints are of wrong billing, low voltage , loose spans , shifting of poles , augmentation of DTR capacity

Monitoring of LT Fuse Off Calls in Hyderabad City

96% of the complaints are being resolved with in 1 Hour 52% of the complaints are being resolved with in 30 minutes

Monitoring of Power Supply to Industrial dedicated express feeders • •

Monitoring of power supply to Industrial dedicated, express feeders and Industrial estates being done by Senior level officials. (DE / Operation & ADE / Operation) Segregation of 4 Nos 33 KV feeders and 64 nos 11 KV feeders are contemplated for FY 2003-04 and 90% of feeders are completed 106

In d u s t r ia l E x p r e s s F e e d e r s V o l ta g e

L e v e l

N o s

22 0 K V

2

13 2 K V

2 7

3 3 K V

7 6

1 1 K V

22 5

T o ta l

33 0

Interruptions to Industrial dedicated express feeders

11K V F e e d e r s

6000 4000 11K V 2000 0 2 0 0 1- 0 2 2 0 0 2 - 0 3 2 0 0 3 - 0 4

Reliability Index Ensuring reliable Power supply and effective monitoring are the most important aspects of Power Utility functioning. • • •

•

Ensuring reliable supply fulfills the promise made to its customers and Effective monitoring helps to improve the same and also assists in systematic planning/ improvements for future. International reliability indicators like SAIFI, SAIDI, CAIDI help not only in understand the existing status of power supply but also are good indicators to compare and benchmark the Utilities for improved performance. Also indicators like Low voltages/High voltages are monitored.

107

Reliability indicators - (Hyderabad - CPDCL) Monitoring the Reliability indicators has been initiated in Hyderabad and the same is done for all the 34 Towns and will be extended to MHQs SAIFI = System Average Interruption Frequency Index Average No.of Interruptions per 1000 Customers = No. of Interruptions occurred on the feeder X 1000 / No.of Customers existing on that Feeder SAIDI = System Average Interruption Duration Index = Total Duration of Interruption per 1000 Customers. = Total Duration of Interruption occurred in minutes on the feeder X 1000 / No.of Customers existing on that feeder CAIDI = Customer Average Interruption Duration Index. = SAIDI / SAIFI. = Average Interruption Duration

SAIFI

SAIDI

1500

70.00 60.00

1200

50.00

Durationof Interruptionsin Minutes

30.00 20.00 10.00 0.00

SAIFI

Hyd-N

Hyd-C

Hyd-S

HYD

59.25

49.65

46.82

52.30

900 600 300

Hyd-N

Hyd-C

Hyd-S

Apr 03 – Mar 04 CAIDI

28 26 24 22 20 18 16

CAIDI

Hyd-N

Hyd-C

Hyd-S

HYD

26.26

23.93

23.62

24.83

Apr 03 – Mar 04

108

HYD

SAIDI 1555.82 1187.99 1105.76 1298.33

Apr 03 – Mar 04

InterruptionDurationin Minutes

Frequencyof Interruptions inNumbers

40.00

CPDCL - % Failures of Distribution Transformer

Introduction of Spot Billing • •

•

Spot billing was introduced in order to reduce several functions to few in metering, billing & collection. Spot billing was introduced first in Hyderabad, the capital city of A.P. in November ‘2001, wherein the bills were issued on the spot to the consumers with the help of a hand held computer. With the remarkable results noticed (improvement in the billing demand and customer satisfaction), spot billing has been extended to all the districts of the State.

Spot Billing with Hand Held Computer •

Fast

•

Versatile

•

Intelligent

•

Affordable

•

Light weight

•

User Programmable

109

Benefits of Electronic Spot Billing • • • • • •

Bills are issued on the spot thereby the consumers are able to get different due dates, hence it avoids rush at payment centers. Focus on attending to exceptionals. Better monitoring of demand, especially of rural areas Reduction of Billing complaints Better cash flow On the spot updation of billing records and payment of bills is possible with GSM (Cellular) feature which can be incorporated with Hand Held Computers .

Collection facilities • •

• • •

Payments can be made through our regular Electricity Revenue Office (ERO) Tie-Up with e-seva centers for bill payment and able to pay any where by the consumers. (at present 36 e-seva centers available in and around Hyderabad city and 3 e-seva centers Anantapur) Payments can be made through certain agencies like bill junction.com Online payment can also be made through citibank from our web site “www.apcentralpower.com” E-clearance facility has been introduced recently, which enables the consumers to pay directly thro’ the bank.

Organising farmers’ Meetings • • • •

Substation wise monthly meetings with the Farmers to understand their issues relating to Power Supply. Taking appropriate action to improve. Communication and interaction with Farmers (along with Agriculture dept,Ground water dept and Irrigation dept officials )to adopt I.D crops in view of draught. Explaining the Power availability position in view of low Hydel availability

S l.N o

1 2 3 4 5 6 7

N ame o f th e R u r a l C ir c le

N o . m e e t in g s

N o. of

co n du cte d (S u b-

Fa rme rs

s ta t io n w is e )

p a r t ic ip a t e d

59 89 135 89 145

1172 1966 3490 2003 1867

6

110

76

2621

599

13229

A n a n ta p u r K urno o l M a ha b ub na g a r N a lg o n d a M edak R a ng a re d d y N o rth R a ng a re d d y S o u th T o ta l

Vidyut Adalats held from May 03 to Mar 04 • •

Vidyut Adalats conducted to resolve the Consumer grievances relating to Metering and Billing issues . Mandal wise meetings attended by ADE/AE with the support of Revenue staff to resolve the grievance on the Spot.

110

Action on reduction of Pilferage and Theft of Energy • • •

Systematic approach in detection and strict action on Theft and Malpractice cases has resulted in not only improved revenues but also reduction of DTR failures and line interruptions. This in turn has improved the reliability and quality of Supply. This has also resulted in getting the cooperation of good customers

Hyderabad – SCADA Project • • • • • • •

Minimal time of interruption to consumers due to centralized control of operations Immediate feedback on shutdowns and LCs to consumers Faster identification of Fault locations and hence reduced downtime Safety of the equipment and personnel ensured due to coordinated control Common single phone number to report any complaint regarding supply to any consumer Line clears are properly planned keeping alternative supplies available to maximum possible consumers thus improved availability of Power One point contact for any information and assistance regarding supply 111

Trouble Call Management (TCM) • • •

A four digit telephone number ‘1912’ is catering to the needs of all the Consumers of Twin Cities and 10 Municipalities of Rangareddy District. District Complaint Registration Cell (DCRC) is functioning to receive the complaints from consumers of other five Districts of APCPDCL Communication to concerned fuse-off call office and monitoring the complaints.

Benefits to the Customers due to various initiatives • • • • •

Citizens charter implementation and monitoring through the Call centers has enabled the utilities to deliver the services promised to the customers. Customer service centers at all the Subdivisions have immensely benefited the consumers Spot billing has enabled transparency and improved credibility of the Utility for the customer point of view in addition to improving the revenues of the companies The % of wrong and defective billing has come down substantially after conducting Vidyut Adalats and taking action accordingly Low voltage pockets have been almost eliminated and the voltages have improved by 10%.

Conclusions & Way forward • • •

• •

Due to unbundling the companies have been able to focus more on the consumer service with in their jurisdictions and have taken up many initiatives for improvement. Companies have become more responsible and Regulatory intervention , oversight and Directives have helped in formulating Service Standards and effective measuring systems. Formulation of Citizens Charter with inputs from Government and Regulator which is a road map for Service Standards levels has been important first step towards effective consumer service. Monitoring of compliance through Call centers,SCADA and through customer surveys has immensely helped in improving the service. Technological improvements and creating infrastructure in a prudent methodology has helped the companies in improving internal efficiency and improve service

Way forward • •

• •

Further implementation of IT to reduce cost and improve service.Areas like Energy audit,AMR,Remote metering etc Consumer Indexing , GIS software implementation and interfacing this with SCADA will result in better energy audit and fault location identification.This will help also help in reduction of Commercial losses and improved consumers service . Implementation of SCADA at Distribution Company level in a phased manner. Monitoring of Reliability Indicators like SAIFI.SAIDI & CAIDI to be commenced for all towns in a phased manner.

112

Data Communication Architecture using IEC 61850 Protocol for Substation Automation R. P. Gupta, M. Pandey and N. Srivastava Department of Electrical Engineering Indian Institute of Technology, Kanpur

1.

INTRODUCTION

Substation automation is increasingly being popular among electric utilities, industries and academic institutions. Substation automation enables supervisory control and data acquisition (SCADA), data collection and control capabilities at the substation, where its functions and operations are monitored remotely from a control centre. This is achieved through a reliable data communication system using modem, high-speed communication lines, fiber-optic cables etc. The data must be understood in the same way by both the devices at transmitting and receiving end while communicating with each other in the substation. These devices having one or more processors are known as Intelligent Electronic Devices (IEDs). The communication among IEDs is achieved using standard protocols. So far, various protocols have been in use. These are Modbus, Modbus Plus, and Distributed Network Protocol (DNP) 3.0. Modbus does not support utility integrated environment over local area network. DNP 3.0 requires vendor dependent mapping table [1]. Looking these shortcomings, an American standard has been emerged for substation automation in the form of Utility Communication Architecture (UCA) 2.0 [2]. Later on it has been realized to make a single substation automation protocol all over the globe. Consequently IEC61850 [3] incorporated most of the features mentioned in the American standard UCA2.0. Unlike other communication protocols, IEC61850 provides interoperability among different IEDs i.e. this standard does not suffer from vendor dependency while adding the new automation feature in the substation. In this paper, the data communication architecture of IEC 61850 is described.

2.

ADVANCED SUBSTATION AUTOMATION SYSTEM

Substation equipments, in general, can be categorized into primary equipments and secondary equipments. Primary equipments include transformer, switchgear etc. Secondary equipments include protection, control and communication equipments. Further secondary equipments are categorized into three levels in IEC 61850 standards. These are station level, bay level, and process level. Station level consists of station computer with a database, the operator’s workplace, interfaces for remote communication etc. Bay level consists of control, protection and monitoring unit per Bay. Process level consists of typically remote I/Os, intelligent sensors and actuators as shown in Fig.1. The station level equipment communicates data with bay level equipment through station bus. Further, bay level equipment communicates with process level equipment through process bus as depicted in Fig. 1. Control Center

HMI

6

Engineering

5

5 3

4

3

Other Other devices Other devices devices

Router

Station Bus Ethernet Switch

2 Bay Controller

Relay B

Relay A

Bay Controller

Process Bus Modern Switchgear

Modern CT/VT

Relay A

3

1 Modern Switchgear

Fig. 1 Substation automation topology 113

Relay B

Modern CT/VT

These buses i.e. station and process buses are realized through the standard Local Area Network (LAN). Station bus is created by installing a multiport Ethernet switch. Switch is a device in the network that filters and forwards packets between LAN segments. Generally Router, Human Machine Interface (HMI) and Engineering console are connected with Ethernet switch at station level. Router facilitates data communication between substation and Master Control Center (MCC). HMI enables the operator to monitor and operate the switching elements in the substation through Graphical User Interface (GUI) at substation level. The engineering console, as depicted in Fig 1, provides computer aided control decision which can be implemented at primary equipment level through local HMI. If station level node has to communicate process level node, it will send the message to bay level node through Ethernet switch. Ethernet switch will send the message to the appropriate node at bay level. This bay level node executes its function and forwards the message to process level node through Merging Unit. Merging Unit acts like a switch and provides the appropriate path to messages. Eventually, the function will be performed by the process level devices. The main focus of IEC 61850 series is to support the substation functions through the communication of (numbers in brackets refer to the Fig. 1) : · Sampled value exchange for CTs and VTs (1), · Fast exchange of I/O data for protection and control (2), · Control and Trip signals (3), · Engineering and configuration (4), · Monitoring and supervision (5), · Control-center communication (6), · Time-synchronization, etc. Other functions such as metering, condition monitoring and asset management are also supported in IEC 61850. Many functions are implemented in IEDs as shown in Fig. 1. Several functions may be implemented in a single IED or one function may be hosted by multiple IEDs. IEDs communicate among each other by information exchange mechanisms of the standard. Therefore, functions distributed over more than one IED may also be implemented.

3.

STATION BUS AND PROCESS BUS

As explained above station bus connects the station level and bay level devices. Process bus connects the process level and bay level devices. Typical diagram of substation automation system is given in the Fig. 2. HMI and ComU reside in the station level. HMI is the interface to the operator at the

Fig. 2. Station bus and Process bus 114

Here operator can control and monitor the substation locally in the substation. ComU is the interface between substation and MCC. These devices are connected to bay level devices via station bus. The substation control system will communicate with protective devices and bay processing unit through station bus. The station bus is specified in the IEC 61850-8-1 part. This part of the standard is still under progress. Many IEDs, that are used to take the decision for different functions of the substation, reside at bay level. They are connected to the primary equipments at the process level through process bus. The process bus eliminates the conventional hard wiring between the process level devices and bay level devices such as protection and control units. The process bus communication is mainly based on the same services as that for station bus communication. There are only two additional services for the process bus. The first one is the fast and reliable exchange of tripping commands between protection devices and switchgear. The second one is the transmission of instantaneous values from electronic transducers. These two services need to be executed immediately on the communication stacks. For this reason, fast Ethernet has been chosen as basic technology for the process bus. All services that are common in station and process bus have been mapped in the same way. Due to high performance requirement for trip command and cyclic instantaneous data, it is not possible to map these services through MMS. Therefore, these services are directly mapped to Ethernet which gives maximum performance and control over the transmission behaviour. This is realized through the serial unidirectional multidrop point to point link and it is specified in IEC 61850-9-1. The other part IEC 61850-9-2 is still under progress for process bus.

4.

DATA COMMUNICATION STACK AS PER IEC 61850

The services defined in IEC 61850-7-2 are called abstract services. Abstract means that only those aspects that are required to describe the actions on the receiving side of a service request. They are based on functional requirements. How these services and the models (Server, logical devices, logical nodes, data, data sets, report controls, log controls, setting groups etc.) are implemented using a specific communication stack, i.e. a complete profile are defined in the Specific Communication Service Mapping (SCSM). One SCSM is the mapping of the services to Manufacturing Message Specification (ISO 9506) [4] and other services like TCP/IP and Ethernet as shown in Fig. 3. Additional mappings to other communication stacks are possible.

Classes: IEC 61850-7-4 IEC 61850-7-3

Information models

ACSI: IEC 61850-7-2

Information exchange, ACSI

SCSM: IEC61850-9-x

Application

MMS (ISO 9506)

Presentation

ASN.1/Presentation

Session

Session

Transport

TCP

Network

IP

Data Link

Ethernet, …

Physical

Physical

Station Bus IEC 61850-8-1

Fig. 3 Data communication stacks ACSI: Abstract Communication Service Interface SCSM: Specific Communication Service Interface

115

General communication stack is given in the Fig. 3. The top layer in Fig. 3 represents information model in object oriented format. The substation functions are executed using the Abstract Communication Service Interface (ACSI) layer. ACSI is a virtual interface to an IED to provide abstract communication services, for example connection, variable access, unsolicited data transfer, device control and file data transfer, independent of the actual communication stack and profile used. ACSI services are mapped to TCP/IP services using Manufacturing Message Specification (MMS). MMS is an internationally standardized messaging system to exchange real time data and supervisory control information between network devices and computer applications in a manner that is independent of: i) application function being performed ii) developer of the device or application. MMS services are applied to the presentation layer and rest of the stacks behaves as OSI layer for the station bus as specified in the IEC 61850-8-1, a part of the standard. At present, two mappings are under discussion in IEC. The first is mapping to Ethernet with TCP/ IP and MMS as application layer. This mapping was included in the standard series to harmonize the IEC and IEEE standardization activities. As shown in the Fig. 3 process bus defined in IEC 61850-9-x had replaced the 4 layers of OSI standard.

5.

PRINCIPLE OF MAPPING TO THE SERIAL UNIDIRE CTIONAL MULTIDROP POINT - TO - POINT LINK

Communication between bay level and process level is thruough the Merging Units, which is used to transmit the message as shown in Fing 4.

Line protection

Bay controller

E th ern et C ontroller

E th ern et C ontroller Serial unidirection m ultidrop point-to

Proprietary link

Proprietary link

M ultiple P o rts E th ern et C ontroller M erging unit

Synchronizati test and confi interfaces

Binary inputs

Fig 4 Example for the use of the serial unidirectional multidrop point to point 116

The communication between transducers such as Electronic Current Transformer (ECT)/ Electronic Voltage Transformers (EVT) and Merging Unit may be through proprietary link to execute protection and control functions. Binary inputs from primary equipments through sensors and actuators are also connected with Merging Unit. The Merging Unit can also be synchronized, monitored, tested and configured through an independent port. The Merging Unit uses serial unidirectional multidrop point to point link for line protection and bay controller. IEC 61850-9-1 specifies the serial unidirectional multidrop point-to-point link in accordance with the IEC 60044-8. It applies to the communication between Merging Unit of ECT or EVT and bay devices such as protection relays. It defines the communication stack and data unit structures for the application layer. It is used in the process level for line protection and bay controller etc.

5.1

Communication stack

Fig. 5 gives an overview of the communication stack. The link layer is in conformity with ISO/IEC 8802-3. This standard is usually referred to as Ethernet. In the following, the term Ethernet will be used instead of ISO/IEC 8802-3. The relevant device standards will specify whether 100Base-FX, 10Base-FL or 10Base-T is used in the physical layer, depending on the application.

5.1.1 Physical layer : The connection of the merging unit to the secondary equipment can be through optical fiber transmission system. By taking into account and solving the Electro Magnetic Compatibility (EMC) requirements, copper-based transmission system is an option. The preferred version of the fiber optic transmission system is IEEE 802.3 100Base-FX. The 10Base-FL system could also be used for sampling rates below 100 Mbps.

SCSM for ISO/IEC 8802-3: Definition of ASDU’s

Applicatio

Empty

Presentat

Empty

Session la

Empty

Transport

Empty

Network l

MAC – Sub layer ISO/IEC 8802.3 And Priority tagging/VLAN according to IEEE 802.1Q

Link layer

100Base-FX IEEE 802.3

10Base-FL IEEE 802.3

10Base-T IEEE 802.3

Fig. 5 Communication Stack

117

AUI-Int IEEE 8 Physical la

Two fibers are always necessary for the optical fiber transmission system in order to support the link supervision. The twisted pair medium according to IEEE 802.3 10Base-T could be used as an option, if appropriate electromagnetic shield measures are considered.

5.1.2 Link layer : (i)

Ethernet addresses

The Ethernet broadcast address shall be used as a default value for a destination address, which consists of ones in the destination address field. For this reason, no address configuration is necessary on the publisher side. However, the destination address could be configurable as optional features for example, adjust a multicast address to connect a merging unit via switch to bay level devices. A unique Ethernet address shall be used as a source address. Ethernet frame format is given in Fig. 6. (ii)

Priority Tagging / Virtual LAN

Priority tagging according to IEEE 802.1Q is used to separate time critical and high priority bus traffic for protection related applications from low priority busload. MAC Header Destination Address Source Address Priority Tagging Ethertype PDU APDU Fig. 6 Ethernet frame format (iii) Ethertype : An Ethertype based on ISO/IEC 8802-3 MAC-Sublayer is registered by the IEEE Authority Registration. The registered Ethertype value is 88-BA (hexadecimal). The sampled analogue value buffer update is directly mapped to the reserved Ethertype and the Ethertype PDU. 5.1.3 Network layer: This layer is intentionally left empty. 5.1.4 Transport layer: This layer is intentionally left empty. 5.1.5 Session layer: This layer is intentionally left empty. 5.1.6 Presentation layer: This layer is intentionally left empty. 5.1.7 Application layer: The mapping provides the capability, to concatenate more than one ASDU (Application service data unit) into one APDU (Application Protocol data unit) before the APDU is posted into the transmission buffer as shown in Fig. 7 The number of ASDUs, which will be concatenated into one ASDU, is defined with a configuration parameter and related to the sample rate.

118

6.

INFORMATION MODELS OF SUBSTATION AUTOMATION SYSTEM

The information exchange mechanisms rely primarily on well-defined information models. These information models are the modeling methods at the core of the IEC 61850 series. The IEC61850 series uses the approach to model the common information found in real devices as depicted in Fig. 8. All information made available to be exchanged with other devices is defined in this standard. The model provides for the substation automation system an image of the analogue world (power system process, switchgear).

Fig. 8 Modeling approach “The common information” in the context of the IEC 61850 series means that the stakeholders of substation automation systems (users and vendors) have agreed that the information defined in the IEC 61850 series is widely accepted and required for the open exchange of the information between any kinds of substation IEDs. The IEC 61850 series defines the information and information exchange in a way that it is independent of specific implementation. The standard also uses the concept of virtualization. Virtualization provides a view of those aspects of a real device that are of interest for the information exchange with other devices. Only those details that are required to provide interoperability of the devices are defined in the IEC 61850 series. As described in IEC 61850, the approach of the standard is to decompose the application functions into the smallest entities, which are used to exchange the information. The granularity is given by a reasonable distributed allocation of these entities to dedicated devices (IEDs). These entities are called logical nodes (for example a virtual representation of a circuit breaker class, with the standardized class name XCBR). The logical nodes build logical device (for example, a presentation of a Bay unit). A logical device is always implemented in one IED; therefore logical devices are not distributed. 119

Real devices on the right hand of the Fig. 8 are modeled as a virtual model in the middle of the Fig. 8. The logical nodes defined in the logical device (for example, bay) correspond to well known functions in the real devices. In the example, the logical node XCBR represents a specific circuit breaker of the bay to the right. Based on their functionality, a logical node contains a list of data (for example, position) with dedicated data attributes. The data have a structure and a well defined semantic (meaning in the context of substation automation system). The information represented by the data and their attributes are exchanged by the services according to the well defined rules and the request performed. The services are implemented by a specific and concrete communication means (SCSM, for example, using MMS, TCP/IP, and Ethernet among others). The logical nodes and the data contained in the logical device are crucial for the description and information exchange for substation automation system to reach interoperability. The logical devices, the logical nodes and the data they contain need to be configured. The main reason for the configuration is to select the appropriate logical nodes and data from the standard and to assign the instance-specific values, for example, concrete references between instance of the logical nodes (their data) and the exchange mechanisms, and initial values for process data.

6.

DATA CLASS MODEL

DATA classes represent meaningful information of applications located in automation devices. IEC61850 specifies a list of common and substation domain specific -simple and complex- DATA, for example Pos for position, OilFil for oil filtration. The composition of DATA is based on common templates. Any set of DATA instances may be grouped to build DATA-SET instances applying the CreatDataSet service. DATA-SET instances can, for example, be written (SetDataSetValues) or read (GetDataSetValues). An excerpt of a DATA instance (contained in Logical Node MMXU1) is shown in Fig 9. The instance of the Logical Node with the name MMXU1 (instantiated from MMXU) is composed of the instance of the DATA phase voltage named PhV (instantiated from WYE), which is composed of phase A voltage phsA (instantiated from CMV), which is composed of complex value cVal (of type Vector), which is composed of voltage mag (of type AnalogueValue), which is composed of floating-point value f (of type FLOA

120

Fig 9 Example of data class model (32). The Data Attribute has additionally the functional constraint FC=MX (measurand) and the trigger option TrgOp=dchg (data-change). (32). The DataAttribute has additionally the functional constraint FC=MX (measurand) and the trigger option TrgOp=dchg (data-change).

7.

Conclusion

Having appropriate modeling and object oriented approach, IEC 61850 makes it easy to access the functions. The modeling uses the Logical Nodes (and their data that represents a huge amount of semantical definitions) primarily as building block to compose the visible information of a substation automation system. The models are used for description of the information produced and consumed by applications and for the exchange of information with other IEDs. Different levels decide the topology of the substation automation system. Standard gives the actual status of all physical devices and logical nodes. There is better control of substation automation, as actual status and the data traffic for all physical and logical links between the logical nodes are known. The resources of the communication network are properly shared and interoperability is supported by means of the network. Thus by the relevant functional architecture and proper modeling of the functions and information, IEC 61850 is the fastest emerging protocol in the field of substation automation. IEC 61850 contains all the possible functions which can be derived from the substation. So it contributes proper controlling, protection, logging, and reporting. The system is reliable and safe status.

REFERENCES (1)

(2) (3) (4)

(5)

R.P. Gupta, Mitali Pandey, “A Comparative Study of IEC61850 Communication Protocol with DNP 3.0 and UCA 2.0 for Substation Automation” in the Proceedings of COMMUNICATION PROTOCOL FOR POWER SYSTEM AUTOMATION, CPRI Bangalore, January 22-23, 2004. Karlhienz Schwarz, “IEEE UCA and IEC61850 Applied in Digital Substations” in the proceedings of DISTRIBUTECH EUROPE, Vienna, October 10-12, 2000. IEC61850: Communication Network and Systems in Substations, Part 1, August 2003. R. Gross, H. J. Herrmann, U. Katschinski, P. Memke, A. Ostermeier, J. Schmid, M. Wache, “Substation Control and Protection System for Novel Sensors.” Session 2000 Cigre UCA (one). “Overview and Introduction to the Manufacturing Message Specification (MMS)”, Available at: www.sisconet.com/downloads/mmsovrlg.pdf

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Looking ahead at Power Distribution Business V. N. Manohar Former Director-in-Charge Tata Consulting Engineers

INTRODUCTION 1.

2.

3.

The recent notification bringing into force the Electricity Act 2003 is likely to transform the Indian power sector dramatically. The all party support that the Act received in Parliament is an indication that the “will of the people” has asserted itself against the well entrenched State Electricity Boards (SEB), who have not been able to meet the aspirations of the people for reliable power of acceptable quality at affordable cost. At one stroke the new Act, has removed the total regulatory, technical and tariff setting powers of the State Electricity Boards over the power sector and have vested powers of regulation as well as tariff setting and the resolution of disputes with independent State Electricity Regulatory Commissions (ERC), with technical requirements to be specified by the Central Electricity Authority (CEA). The Act has given a direction for liberalization and competition in the power sector that was totally lacking. As more players enter the sector, some in niche areas, competitive forces will force a change of mindset on all those involved in the power sector, and they will be made to look on electricity supply as a “business” to which principles of business management will have to be applied for survival, growth and success. This paper attempts to look ahead at likely changes in this vital infrastructure sector with focus on distribution.

THE ELECTRICITY ACT 2003 4.

The Electricity Act recognizes four basic activities in the power sector, viz. generation of electricity, transmission of electricity, distribution of electricity, and trading in electricity. The last item of “Trading” is an important new addition to the Indian power scene. Among the key provisions of the Electricity Act are : Among the key provisions of the Electricity Act are :

a.

b.

c.

d.

e

f.

No permission is required for thermal generation and for hydroelectric generation it is required only to ensure that the proposed river works are in the best interests of the river development and are consistent with the requirements of drinking water, irrigation etc. Captive generation is totally free from controls with the right of “open access” from the captive generating plant to destination of use. The ERC has been granted the power to exempt from licensing, for transmission, distribution or trading in electricity, any local authority, panchayats, user associations, cooperative societies, NGOs or franchisees. While open access is available to transmission systems on payment of appropriate charges, open access in distribution systems is to be introduced as per a schedule to be specified within one year. It has also been provided that the Tariff regulations shall promote cogeneration and generation of electricity from renewable sources of energy. Stand-alone systems including those based on renewal sources of energy and other non-conventional sources of energy are to be permitted for rural area. Bulk purchase of power and management of local distribution in rural areas through panchayats, user associations, cooperative societies, NGOs or franchisees will he encouraged and ERCs have been given the authority to exempt them from licensing. Section 65 provides that if the state government requires the grant of any subsidy it shall pay the requisite amount in advance to the licensee of electricity or any other person concerned to implement the subsidy. 122

5.

While far reaching in its approach, the Act is an enabling legislation providing a proper road map for the future of the power sector. Rules framed under the Act will decide the speed at which improvements will take place, and decisions of the ERCs will be crucial to the actual operation of this Act in practice. It is hoped that the government and the SEBs will not resist the unfolding changes, but play a proactive role in accepting the direction of liberation and competition that has been set out by the new Act.

FORTHCOMING CHANGES 6.

7.

8.

9.

10.

Already there are signs of major initiatives by the private sector in the electricity business. For example, Reliance Energy and Tata Power have both planned to set up a number of power stations, as the power can now be transmitted from any power station to areas where they are distributing licensees, after paying wheeling charges. It is likely that large industrial consumers who now pay a very high tariff will cooperate with, or even promote, private generating companies and obtain their own power supply using the existing transmission and distribution network, but bypassing the SEBs. The SEBs will thus lose their high value industrial consumers making their financial position even more precarious. The acceptance of power trading as a major activity in the power sector by the Electricity Act has already motivated a host of new players. Reliance Energy and Tata Power have both set up separate companies for power trading and have invited offers for supply of power. The government has set up the Power Trading Corporation for trading in power for central utilities and NTPC has also set up a group for power trading. More players will soon emerge and with it the pricing of power will be brought into much sharper focus. Many states are considering bringing private players into the distribution sector and with it the much needed investment. Options of privatization of district-wise area for distribution, giving management contracts without transfer of assets, forming rural power supply cooperatives, and improving the performance of selected areas to make them models of excellence in distribution are all being considered. These rapid changes have taken placed within a few months of the Act being notified. They are an indication that the power sector is, at last, likely to go through a much needed transformation.

ELECTRICITY REGULATORY COMMISSION 11.

The main regulatory body overseeing the operation of the Act is the state ERC, which is independent of the state administration. It is possible that different state ERCs may go in different directions. Recently the Tamil Nadu ERC has decided not to include any subsidy from the state government in the tariff calculation. The Maharashtra ERC has provided for a surcharge for the T&D loss in the areas where the loss is high, so as to bring home to the consumers that they are paying a charge for the inefficiency of the SEB. There is also the danger, as has happened in some states, that the state government and the ERC take an adversarial stand, which is not conducive to the smooth working of this important sector. While independence of the ERCs is necessary for them to take quick decisions based on local needs, some degree of coordination between the ERCs, preferably voluntary, is desirable to avoid regulations in different parts of the country going in different directions.

GROWTH OF DISTRIBUTED GENERATION 12.

Distributed generation refers to smaller generators that can integrate with the distribution systems. These could be renewable, viz. solar, wind, minihydro, as well as non-renewable, viz. diesel engine, combined cycle, microturbines and the like. These may be installed by either those who need the power for their own use and can offer the surplus power to the distribution system or by new entrants in generation as these units may now be allowed to run in parallel with grid supply with certain safeguards. This will permit a large number of 123

13.

14.

captive units to feed into the grid, particularly at peak loads, reducing the need for capacity addition and also increasing the overall operating efficiency. The scope of such injection of power at distribution level is quite large as new technologies for biomass generation, more efficient wind generators and low cost minihydro have now matured. As an example, in the United States non-utility power generation added every year is higher than that by traditional electric utilities. With distributed generation able to supply a significant part of the load in the vicinity, distribution system losses will come down and the need for EHV transmission will reduce. The whole electric supply network configuration can change from that we see today. Further a large number of small generating units distributed throughout the network will increase reliability and reduce the chances of state-wise blackouts, and speed up restoration of power. Stand-alone generation with its associated small distribution system could show significant growth, as the Electricity Act now expressly provides for such systems and they may be totally exempt from licensing. In remote areas where there is no grid supply, stand-alone systems based on minihyro or biomass generation, perhaps integrated with diesel engine generators, would be a viable option and will bring the benefits of electricity to areas where it will be uneconomic to extend the transmission grid. As these local networks increase in size, and the grid also expands over time, they may eventually get interconnected.

SYSTEM CONTROL 15.

16.

17.

With such changes in system configuration, and with a non-utility orientation to many aspects of the electricity “business”, providing a proper control of the overall system for proper voltage, stability, and security will become a real challenge. Supplies from some generating sources such as wind and solar will have to be accepted by the network as and when available, and this may pose problems wherever these sources are a significant proportion of the total generation. Some of these problems are technical, such as the need for reactive support for the induction generators of wind turbines, and the need for providing system reserve to cover the unpredictable and fluctuating output of wind and solar generators. With distributed generation, protective relaying will become complex and special care will be needed for proper relay co-ordination under different operating conditions. The need to keep track of system operating conditions at all times will require the use of SCADA systems on a much larger scale than hitherto. Another set of problems arise in deciding which agency should provide the generation reserve, how it will be paid for and how the responsibility for the overall network stability, security and quality of power, will be shared by the numerous parties, each with their own commercial interests and priorities. The distribution licensee will not be able to operate a passive system as hitherto, but will have to integrate the operation of the various types of generation sources distributed throughout his system with the industrial, commercial and other loads, taking into account technical restraints and different commercial agreements. The distribution system will, in effect, be a small but complex utility and will require technical and managerial skills of a high order for its operation and control.

EFFICIENCY IMPROVEMENT 18.

As competitive forces emerge in the power sector, they will force distribution companies to improve their operating efficiency. First and foremost they need to cut down aggregate technical and commercial (ATC) losses, and improve their meter reading, billing and collection cycle. Technical losses are also high and need to be reduced by well-known methods of reconfiguring the distribution network, reconductoring the distribution feeders, and installing fixed and switched capacitors. This can make a major impact on their financial health in a short time.

124

19.

20.

Other techniques such as the use of time-of-day metering, and demand side management could be used to flatten the load carve and reduce peak demand. With a general focus on efficiency improvement, there will be more attention on improving end-use efficiency, and the use of CFL lamps, high efficiency motors, variable speed drives will increase. Attention will be needed not only to improve the technical performance and operating efficiency of the distribution system but, more importantly, to streamline the commercial aspects of the business. The APDRP program launched by the Ministry of Power has provided large funds for improvements of distribution systems. However, the funds have been under utilized and that too for routine strengthening of the network. Very little has been spent for new technology in this sector. It is hoped that as SEBs become aware of likely changes in their distribution systems, they will use APDRP funds to bring in new technology, which will surely be needed.

REDUCING WASTAGE IN AGRICULTURAL SUPPLY 21.

22.

23.

24

25

26

27

With greater attention to energy efficiency, the energy wastage in the agricultural supply can no longer be ignored. One of the persistent problems seriously affecting the financial health of the SEBs, is the very low tariff (or even zero tariff) for the agricultural sector. This policy was initiated to promote the use of electrical pump-sets for agriculture. However, it has outlived its usefulness, and it has been found that large well-to-do farmers are reaping most of the benefits. However, because of vested interests that have developed over the years, it is almost impossible to raise the tariff to commercial levels. Numerous studies have shown that such low tariff does not benefit the farmers as it is accompanied by power supply that is neither available, reliable or of acceptable quality. The resultant cost to the farmer of unavailability of irrigation water when needed, cost of motor burnouts, excess capital cost in buying oversize pump-sets etc. is much higher than the benefits of low tariff. However, a low power tariff has other serious consequences. It results in almost zero incremental power cost to the consumer, with the result that the pump-sets are rarely switched off and they run whenever power is available. This results in wastage of electricity and fosters excessive drawal of water resulting in lowering of the water table with other associated problems. If the slogan of “Sadak, Bijli aur Pani” is to be realized, the first imperative is to stop wastage of electricity and water, which has come about as a side effect of the low tariff for agriculture. The subsidy to farmers is a political decision. However the consequential wastage of electricity and water needs to be tackled urgently. In the present situation this can only be done by either providing a service which the farmer is willing to pay for at commercial rates, or to delink subsidy from the electricity tariff. A key finding of a World Bank study for Haryana is that farmers appear willing to pay for improved availability of power. A similar conclusion was reached by field surveys in other states. If reliable, quality power is made available to farmers 24 hours a day, 365 days a year, it is likely that they will agree to pay commercial rates for electricity. Once this happens, they will have an incentive to use high efficiency pump-sets, use the power only when required and in general use electricity efficiently. This should be tried for an area supplied from one substation dedicated to provide reliable power, with proper voltage at the consumer terminals. A modification of the above approach would be to supply power for 6 to 8 hours a day as at present, at off-peak periods at the current low or zero rate and at full commercial rates throughout the rest of the day, using time-of-day metering. A most effective method would be to subsidize drip irrigation instead of electricity. Use of drip irrigation reduces water consumption by 40–60%, reduces fertilizer use by 20–30%, increases crop yield by more than 100%, and reduces energy for water pumping by 30–50%. Many state Governments promote drip irrigation. This can be done on a much larger scale with electricity provided at commercial rates, as it is a win-win situation all round, and it will save electricity, water and increase yield at the same time. 125

28

29

Another method is to motivate consumers to save electricity by use of high efficiency pumpsets, improved piping and suction values etc. at their own cost with soft loans from banks. The energy saved is virtual power generation for the SEB, who should offer to pay the consumer at, say Rs.2 per unit, for the saved energy. An automatic energy audit system should be provided to prevent misuse. All would agree that wastage of water and electricity should be stopped. The problem is very serious and a major initiative is required to bring it under control.

CUSTOMER FOCUS 30.

31.

As distribution licensees appreciate that their business is “electric power supply retailing” the normal business strategy of customer focus will have to be applied. Understanding the needs of the consumer and trying to meet them will become important. Such an exercise will have to start with updating the customer database, and the distribution system database with digital mapping of the entire network using GPS, and introduction of a comprehensive asset management system. This will provide the base required to introduce a computer-based decision support system for rectification of faults, as fault location and manpower mobilization can be decided quickly. With this, customer complaints can be attended to easily as the information required to do so will be available at the touch of a button. The business concepts of customer relationship management (CRM) and the setting up of call centers will then follow.

APPLICATION OF INFORMATION TECHNOLOGY 32.

33.

In a widespread power distribution network serving lakhs of consumers and growing continuously, no manual system can be adequate to collect, collate and process information in a timely manner for decision making. Only computerized systems using the tools of Information Technology can serve the purpose. The power sector, although crucially important to the economy, has not improved its business processes over decades. This, in spite of the fact, that the electricity business lends itself to IT use where immediate measurable benefits are realizable. Other infrastructure sectors, such as telecom, financial services, airlines and even banks – usually the most conservative – have used Information Technology to significantly improve their performance. The necessary software capability as well as system design expertise is abundantly available in the country, but because of the attitude of the SEBs, the Indian IT industry has not so far made any significant inroads in the power sector and has preferred to look for opportunities elsewhere. It is obvious that the changing distribution systems will require comprehensive computerized systems and sophisticated IT solutions for their management. These will be required not only for maintaining an up-to-date database of all types, but to cover technical aspects of monitoring and control, as well as business aspects of billing, revenue collection, energy accounting etc.

CONCLUSION 34.

35.

The Electricity Act 2003 has freed the power sector from crippling controls, and major changes are in the offing as a result of liberalization. The distribution sector is also poised to undergo a major transformation as managements start looking at it as business of electricity retailing. Technical innovations for efficiency improvement, comprehensive application of IT in all aspects and the use of business management principles are likely to transform the distribution sector in the coming years, and with it the consumer is likely to realize his dream of reliable and quality power at an affordable price.

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Supervisory Control And Data Acquisition (SCADA) Laboratory for Research & Training in Distribution Automation Mini S. Thomas, Parmod Kumar

Abstract : This paper reports a unique SCADA Laboratory facility for power systems at Jamia Millia Islamia, New Delhi. It has been designed to function as a research and training center for utilities, faculty members & students. The paper covers the functioning of the SCADA/EMS laboratory facility, based on Distributed-processing technology. The SCADA laboratory is currently providing hands on experience to students and practicing engineers and is giving them an insight into the contemporary SCADA systems. This lab is the first of its kind to be functional in India and may be unique. Keywords: SCADA systems, Distribution Automation, Ethernet, Intelligent Control, Laboratory, Real Time Systems, DCS

I. INTRODUCTION Power is a critical infrastructure for the growth of Indian economy. Acceleration in the economic growth will depend upon a financial and commercially viable power sector that is able to attract fresh investments. Currently electrical energy constitutes about 20% of the total annual energy consumption on a worldwide scale with an ever-rising demand. The power sector in India at this juncture is plagued by a number of problems. These include inadequate generation capacities, poor capacity utilization, very high transmission losses and poor project implementation. Plant load factor in most of the plants has been very low compared to the power plants in other parts of the world. The sector has been bogged down by resource constraints. Not withstanding the massive increase in generation capacities over the past decades, the history of the Indian power sector has been punctuated by shortages, massive pilferages and a demandsupply gap, which has been growing. The shortages have been so chronic that, at times fears have been expressed about a negative impact on industrialization due to these shortages. It is thus imperative that power utilities look at increasing efficiencies in distribution networks, which have among the highest transmission and distribution losses in the world at upwards of 30 per cent. Distribution automation is a tool for enterprise-wide management of an electric utility system. In other words, distribution automation, if properly applied, provides for efficient operations enhances operational outputs and translates into economic benefits. Distribution automation through SCADA systems directly leads to increased reliability of power for the consumers and lower operating costs for the utility. It results in forecasting accurate demand and supply management; faster restoration of power in case of a downturn and a quick, alternate arrangement for power for important/emergency locations. The utilities are in a better position to undertake both active and reactive power management and with better anticipation of trouble and greater trouble-shooting through remote access. Predictive maintenance results in reduced cost of maintenance of power system devices, thereby extending their life. Distribution automation through SCADA also reduces human influence and errors.

Mini S Thomas is working as Professor in Electrical Engineering, Jamia Millia Islamia, Jamia Nagar, New Delhi, INDIA 110025 ([email protected]) Parmod Kumar is working as Professor and Head, Department of Electrical Engineering, Delhi College of Engineering, Bawana Road, Delhi, INDIA 110042 ([email protected]) 127

Although many utilities are talking about distribution automation, this has not taken off the way it should have. There are many reasons for this condition. First of all, the lack of adequate knowledge among utility workforce, about SCADA and distribution automation and the immense advantages the implementation will bring about in the power sector. Hence there is an immediate need for proper training facilities in SCADA and distribution in India, for the distribution reforms initiated by the Ministry of Power to go ahead smoothly. Cost factor is also a hurdle, as the cost of a complete distribution automation system for a major city is Rs 30-50 crore, but the general observation is that once a proper proposal is made, finances will flow automatically from sources. The SCADA laboratory at Jamia Millia Islamia has been set up with the view of providing students and practicing engineers with hands on learning experience on SCADA system, and its applications to the management, supervision and control of an electric power system. The setting up of this laboratory is of utmost importance because SCADA systems, though used extensively by the industries, are the proprietary item of each company and hence very few technical details are available to students and researchers. This laboratory is providing research facilities in the form of hardware and software for adaptive and intelligent control of integrated power systems. Research work on preprocessing data at the RTU level using Fuzzy Logic and Fuzzy-Genetic algorithm has already earned recognition [1, 2]. The significance of the laboratory is highlighted by the developments in substation automation, which is revolutionizing the automation scenario in power systems [3]. One of the unique features of the SCADA/EMS laboratory, that makes it the only one of its kind, is the use of a distributed processing system, which supports a global database. The use of such a system was favored against that of personal computers with data acquisition add-on cards [4-6], in order to acquaint students with the standard industrial practices.

II. DESIGN OF THE LABORATORY Large SCADA systems are used in a wide range of applications like power station control, transmission, distribution automation, and smaller SCADA systems are used for industrial automation. In the proposed lab we wanted to give a general idea about SCADA systems which would be applicable to any of the above mentioned processes, in particular for substation automation. Hence designing the specifications for the laboratory was quite challenging and satisfying. SCADA for power systems, distributed in wide geographical areas, is an integrated technology comprising of the following four major components [7]: (i)

(ii)

(iii) (iv)

Master Station: It is a collection of computers, peripherals and appropriate input/output (I/O) systems that enable the operators to monitor the state of the power system (or a process) and control it. Remote Terminal Unit (RTU): RTU is the “Eye, Ear and Hands” of a SCADA system. The RTU acquires all the field data from different field devices, processes it and transmits the relevant data to the master station. At the same time, it distributes the control signals received from the master station to the field devices. Communication System: It refers to the communication channels employed between the RTU and the master station. The bandwidth of the channel limits the speed of communication. Human Machine Interface (HMI): HMI refers to the interface required for the interaction between the master station and the operators/users of the SCADA system.

The proposed laboratory has all the above components of the SCADA system with on-line monitoring & control facilities as shown in Figure-1. The master station has two engineering consoles for project implementation and four operator consoles for system monitoring. The SCADA hardware includes a distributed processing unit (DPU), a remote terminal unit (RTU) and a number of analog, digital and pulse input/output units and field equipment.

128

The communication interface includes the Profibus and Modbus modules, and the LAN in the laboratory is through an Ethernet highway. The system software has the facility for easy online configuration for mimics, trends, reports etc. and for web navigation. An 11KV substation, which is supplying power to the Faculty of Engineering and Technology, is being monitored. The prototype model of a 400KV transmission line and on-load tap changer transformer (with auto-transformer and stepper motor) have been developed, monitored and controlled through the SCADA system, to enable the students to have a feel of a real power system.

III. SYSTEM ARCHITECTURE The architecture of SCADA system used in the laboratory, among the various processors connected to the data-highway, is of distributed function type. Distributed architecture was preferred as this is modular and expandable in future. The SCADA system used in the laboratory is microcomputer based with functional and database distribution. It has open ended system architecture comprising of the system hardware, the system software and human machine interface, which are discussed in detail below:

Analog, Digital, Pulse I/O Units

Spare

Spare

Profibus

AC800F Processor (RTU) Ethernet

Spare

Modbus

Profibus

Ethernet

Power mod

AC800F Processor (DPU)

Power mod

Ethernet

Data Highway

Analog, Digital, Pulse I/O Units

FIELD DEVICES

FIELD DEVICES

RTU - Remote Terminal Unit EA - Energy Analyzer ES - Engineering Station

DPU - Distributed Processing Unit OS - Operator Station

Figure-1: Overview of the Laboratory A. SYSTEM HARDWARE: The system hardware comprises of the processing units, the DPU and RTU, two engineering stations and four operator stations. Each of the hardware components is discussed in detail in the following sections. 129

1.

2.

Distributed Processing Unit (DPU): The DPU is configured around a 32-bit Restricted Instruction Set Computer (RISC) processor AC800F with 4 MB memory as shown in Figure2. It can support up to 100 master less RTUs. At present there is only a single RTU communicating to the DPU. The DPU has a capability of handling more than 1000 inputs and outputs, but it is presently configured for 216 inputs and outputs (digital, analog and pulse). The RTU, DPU and the input/output units are interconnected through the Profibus module. The DPU has the Modbus module for dedicated communication with Intelligent Electronic Devices (IEDs). Remote Terminal Unit (RTU): The SCADA/EMS laboratory has a single RTU that can be stationed at a remote location. Presently in the absence of a sufficiently remote field, the RTU is functioning inside the laboratory itself. The RTU is also equipped with I/O channels (digital, analog and pulse) for capturing the field data, and has the modem for communicating on RS485 link. Like the DPU, the RTU is also configured around a 32-bit RISC processor AC800F. The RTU communicates to the master SCADA system (DPU) through a Profibus. Since the DPU and RTU have the same hardware configuration and are at the same location, they can act as a redundant system at any time, to depict the actual control room experience.

Figure-2: The DPU and the RTU The DPU and RTU are currently performing the Data acquisition, system monitoring and control and the Sequence of Events Recording (SOE) functions in the laboratory: 3.

4.

Input/Output Units: At present the system has 216 input/output channels, including that of both the DPU and RTU. The analog inputs comprise of the signals coming from the voltage and current transducers connected to the various field devices like the 3-phase transmission line, 3-phase load, etc. The digital inputs/outputs are the capacitor bank on/off positions in the substation and the circuit breaker positions on the transmission line and the load. Apart from these, there are pulse inputs and outputs. Data Highway: The laboratory incorporates industry standard networking. It has an Ethernet data highway (coaxial cable) operating at 10Mbps and is currently supporting a network of four operator stations and two engineering stations along with the DPU and the RTU, all connected in bus topology. The DPU passes real time data to the operator and engineering stations via the Ethernet through customized software. The I/O units are connected to the 130

5.

processor through the Profibus. The Modbus module connects the Intelligent Electronic Device, the Energy Analyzer, to the AC800F. The Modbus is incorporated in the system for performing dedicated tasks and for better understanding of the industrial buses. Operator and Engineering Station: The SCADA system has six Pentium-IV Computers (running in the environment of Windows 2000) acting as the operator stations and engineering stations, so that, at a given time, a maximum of 10 students/trainees can work in the laboratory, two on each station, one station is left for faculty members and R&D work. Each of the four operator stations provides a customized, interactive, graphic user interface, designed using modern software programming techniques. The entire field can be monitored and controlled from the operator stations. Presently, as the field equipments being monitored are not very vast, each operator station covers the entire field, but in case of a vast field, each operator station can be configured to perform dedicated monitoring of different sections of the field.

Two Pentium IV computers are serving as the engineering stations for the system. The engineering station runs the engineering software, programmed using Visual Basic 6.0. The commissioning, adding new hardware, changing the tag settings, and associated tasks are performed at the engineering station using the engineering software. B. SYSTEM SOFTWARE : Currently the laboratory utilizes two system software programs for better understanding and proper utilization of the product available in the market. The first one is hardware specific and dedicated software, whereas the other one is an open-ended system software, which can communicate with any hardware device. This is to make the laboratory much more generalized, rather than constrained to a specific hardware. The SCADA software being used in the laboratory has provision for online configuration facilities like creation, modification, and deletion of process parameters in database, mimics, trends and reports. A web navigator has been designed using Java, to enable process management via Internet. The software has secured control facilities for executing individual digital output points or group of predefined points with a single command. It is capable of supporting standard power system software programs like MATLAB and EDSA. The dedicated software used in the system, Freelance 2000, consists of two main modules: Digivis, the operator software and Digitool, the engineering software. Digivis software offers a user-friendly graphical interface in accordance with MS-Windows standard. It provides a comprehensive, standard and free display logging, graphics and display facilities including trend archiving, system diagnostics, etc. Both free display and graphic displays are user-defined and are created using the graphic editor in the Digitool. The archived trend and log files are viewed using Digi Browse. Digi DDE (Dynamic Data Exchange) permits to convert data to ASCII format, making it readable by third party softwares. The Digitool, also known as control builder, is operated in configuration mode where, the project is structured, configured and documented. Configuration can be processed off-line. The project objects are assigned to the hardware structure as part of the system configuration, and can then be downloaded when the connection is later made on-line. Digitool can handle all types of IEC 611313 programming languages like the Function Block Diagram (FBD), Instruction List (IL), Ladder Diagram (LD) and Sequential Function Chart (SFC). All the back end programming is done in Digitool using functional blocks along with the appropriate logic functions. Digitool is a highly extensive module with several useful features such as visual and sound alarms, trend display, time stamping etc. Report of all field alarms and system alarms along with time stamping, description, state and current value is generated. Alarms (visual as well as audio) can be set and displayed as per the requirement. All unacknowledged alarms remain in flashing mode till they are acknowledged. Trend display is another useful tool of this software. By trend display we mean the display of variation of different parameters such as voltage, current, frequency, temperature etc. with time. 131

The software can be configured to give both the past and the current trends. From these trends, we can predict the next trend also. These trends appear in the form of colorful graphs and can be given oscilloscopic form by choosing appropriate scales. This feature makes the software more user-interactive. This allows the students to reconstruct the sequence of events in case of a fault. Open ended software: SCADA portal is an open system software, which enables one to develop highly interactive HMI for remote control and PLC applications. It combines the unique usability features found in HMI with simple integration of control equipment and a variety of IEDs. It can communicate with locally and geographically distributed devices through communication protocols like OPC and Modbus. The applications in SCADA are based on object oriented principle. In the SCADA lab, we have configured SCADA portal using both OPC and Modbus protocols. C. HUMAN MACHINE INTERFACE (HMI). HMI refers to the communication between Man and Machine and is of utmost importance in modern computer based control systems. The HMI in the laboratory has been developed to make it highly descriptive, interactive and user friendly. This was done in order to enhance the student's perception of electrical power systems and their performance. The control elements of the power system and other field devices are graphically modeled on a color monitor. The graphics have been developed in almost an exact replication of the real time field setup, depicting all the field devices exactly as their layout in the laboratory. The control fields have been designed in the form of buttons having different color schemes for depicting different operating conditions such as red for "off" and green for "on". The different visual alarms keep flashing on the top of the screen, till they are acknowledged. The HMI has been designed using both the softwares available, the Digivis and SCADA Portal.

IV. FIELD DESIGN The foremost task in the designing of the laboratory was, defining the power system to be monitored and controlled. This was done taking into account adequate scope for expansion of the system in future, and the latest facilities available in instrumentation and monitoring areas. A number of big industrial houses involved in power system SCADA were contacted, and detailed discussions were carried out with the experts in the field. Also a study of the available industrial SCADA systems was done. Finally, the power system to be monitored, the configuration of the laboratory and the specifications for the field device were finalized. The laboratory field presently comprises of the following: · An 11KV Substation feeding the Faculty of Engineering building, Jamia Millia Islamia. · 3 phase transmission line model, complete with reactive and capacitive compensation. · Energy Analyzer · Prototype model of on load tap changer (OLTC) using stepper motor and autotransformer. · RTD, level Sensors, transducers, contactors Substation monitoring: Provision has been made for the monitoring of an 11kV/440V substation at Jamia Millia Islamia. The substation is located about 150m from the SCADA Laboratory. Exclusive cabling has been laid from the substation up to the SCADA Lab with proper earthing. Voltage, Current, frequency, phase angle and power factor transducers have installed and real time values from the L.T side (440V) of the Transformer have been made available in the SCADA Lab. The substation has 8 capacitor banks installed for power factor corrections, which are automatically switched on depending on the power factor. The On/Off positions of the capacitors are also fed in the DPU as digital inputs.

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Figure-3: The three phase transmission line set-up with autotransformer and stepper motor with drive.

Three-phase Transmission Line: The transmission line model as shown in Figure-3 was built to simulate the real time distribution conditions in the laboratory, so that students could get a hands on experience of phenomenon such as Ferranti Effect, Series and shunt compensation etc. by performing experiments on the system. The transmission line model kept in the laboratory is a scaled down P-model of a three-phase transmission line. The actual field parameters of the existing line were obtained and were scaled down to 230V, 5A range. The parameters for a 10-section Pmodel were computed and the actual inductance values per section obtained. The inductances were designed and wound in the lab itself and the capacitors were obtained readymade. The entire section bearing the capacitance and the inductance was enclosed in wooden boxes with covers. After assembling the lines, testing was done and satisfactory results were obtained with Ferranti effect and other line parameter studies. Each of the 3 phases of the transmission line is connected via autotransformers. The Isolators perform the switching operation and are energized from the operator stations. Current and voltage transducers are connected to sense the incoming voltage and current of each phase, depicting the current and potential transformers on the actual line. Figure-4 shows the transmission line graphics on the HMI screen. To give the students a fair idea of control devices, a 10kg-cm torque stepper motor with autotransformer has been used as an On-Load-Tap changer, connected to the transmission line model. The stepper motor has been mounted over the autotransformer and can be driven by the operator console with pulse inputs.

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Figure-4: Transmission line model graphic

A 3-phase resistive-inductive/capacitive load has been designed and developed to act as the power system load. V and I transducers as well as contactors are connected between the transmission line and the load to measure the voltage drop in the transmission line and also to perform switching operations of the load. The reactive and capacitive compensation of the line during full load and light load conditions are clearly demonstrated using the careful variation of the capacitive and inductive loads. Energy analyzer: The SCADA lab has an Intelligent Electronic Device (IED), a three-phase energy analyzer, connected to the incoming 3-phase supply through the Modbus module to the system. It can monitor up to 25 parameters and is currently configured for the Frequency, 3 phase currents (Ia, Ib, Ic), three phase voltages (Va, Vb, Vc), power factor, real power and reactive power. It directly measures the phase and a neutral voltage, frequency, phase currents and computes other quantities such as voltage between lines, phase power factors, phase active and reactive energies and three phase system energies etc.

V. COMMISSIONING Commissioning of the laboratory involved the following main tasks: · Physical wiring of the devices · Earthing · Tag allocation · Software customization · Graphic design Once all the field devices including the transmission line model were finalized and obtained in the laboratory, the main task was to connect them to the DPU and provide proper grounding schemes. The connection of the various analog and digital devices to the different Input/output channels in the DPU has already been described in the earlier sections. Ferrules bearing the appropriate tags have been attached to all the wires connecting the devices to the I/O channels, for easy identification and tracing, in case any change has to be made. The entire system has been earthed as per industrial standards.

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Tag allocation for various devices was an easy task as memory mapping in the system is automatic and a device connected to the appropriate channel is identified by the system on its own and the users can provide the tag of their own choice. Software customization was done by generating Functional Block Diagrams (FBD) for each of the field devices and then applying the appropriate logic. Audio and Visual alarms were set to indicate different conditions in the devices for e.g. when the Transmission Line current exceeds a particular limit, both audio and visual alarms are generated. Graphical trends were generated for constant monitoring of the different parameter changes with time. Different parameters such as voltage, current, frequency etc. have been plotted in different colors for easy monitoring. Apart from the trends, a second by second record for each of the parameters is maintained in the system. No external circuit/device is employed for this function as all the data coming from the DPU is already time stamped. All the graphics as mentioned earlier have been designed in an exact imitation of the actual field devices and their layout. The actual monitoring of the field is done through the Digivis module of the software. The graphics are highly interactive and easy to understand.

VI. CONCLUSION The SCADA/EMS Laboratory has been designed and commissioned to facilitate the understanding of real time monitoring & control of systems for Electrical Engineering students and professionals. The Laboratory is first of its kind where the students will get hands on experience on the on-line monitoring and control of the Electric Power System. The laboratory was conceived and designed after extensive consultation with Industries and utilities. The components of SCADA systems, master station, RTU, different communication channels and a variety of field equipments are available in the laboratory. The data acquisition is with time stamping, which will lead to sequence of events monitoring. A 3-phase transmission line model with on-load tap changer and static VAR are the highlights of the field equipments. The laboratory gets on-line data from the 11KV substation feeding the Faculty of Engineering. The laboratory has two engineering stations and four operator stations at present, with 216 Input/output units, which can be expanded to 1000. Overall, this laboratory will provide the undergraduate and postgraduate students with a better understanding of industrial SCADA systems, especially as SCADA systems at present are proprietary items of each company. It is proposed to add redundant data highway using fiber optic cable soon. The SCADA Laboratory is primarily used for regular research and training programs for the benefit of Faculty and students of Jamia, in order to give them hands on experience on SCADA systems. Another major emphasis is on doing industrial consultancy and research for the benefit of Industrial houses. In addition, there are regular training programs for practicing engineers on SCADA systems. The courses are modular and would suit both practicing and fresh engineers. The SCADA lab has already trained a large number of engineers from various electricity boards in India and practicing engineers from the Industrial automation sector. Overall, the SCADA lab designing and implementation was a challenging, passionate and fruitful experience.

VII. ACKNOWLEDGEMENT The authors wish to thank Mr. Somendra Kumar, General manager, ESPL, for the necessary advice from time to time in implementation of this project. Thanks are also due to M/s ABB and M/s Industrial IT solutions for the help rendered.

VIII. REFERENCES [1]

Parmod Kumar, V.K.Chandna, Mini S.Thomas, "Intelligent Algorithm for Pre-Processing Multiple Data at RTU", IEEE Transactions on Power Systems, Vol.18, No:4, November 2003, pp 1566-1572. 135

[2] [3] [4]

[5]

[6] [7] [8]

Parmod Kumar, V.K.Chandna, Mini S.Thomas, "Fuzzy-Genetic Algorithm for Pre-processing Data at RTU", IEEE Transactions on Power Systems, Vol. 19. No: 2, May 2004. John D. McDonald, "Substation Automation IED, Integration & Availability of Information" IEEE Power & Energy Magazine, Vol-1, No.2, March/April-2003, pp-22-31. S.P. Carullo, C.O. Nwankpa, "Interconnected Power Systems Laboratory: A Computer Automated Instructional Facility for Power System Experiments". IEEE Transactions on Power Systems, Vol 17, No: 2, pp215-222, May 2002. K.K. Tan, T.H.Lee, C.Y.Soh, "Internet-based Monitoring of Distributed Control Systems-An Undergraduate Experiment", IEEE Transactions on Education, Vol45, and No: 2, pp128-134, May 2002 B. Qiu and H. B. Gooi, "Web-Based SCADA Display Systems (WSDS) for Access via Internet," IEEE Transactions on Power Systems, Vol.15, No.2, pp681-686, May2000 "Fundamentals of Supervisory Systems," IEEE Tutorial Course, 1991, 91EH0337-6 PWR. "Automating power distribution", Alfred Manohar, ABB, http://www.blonnet.com/businessline/ 2001/08/01/ stories/040156ma.htm

IX. BIOGRAPHIES Mini. S. Thomas (M-88, SM-99), graduated from University of Kerala in 1984, completed her M.Tech from IIT Madras in 1986 (both with gold medals) & PhD from IIT Delhi in 1991, all in Electrical Engineering. Her employment experiences include Regional Engineering College, Calicut, Kerala, Delhi College of Engineering, New Delhi and presently as Professor in the Faculty of Engg. & Tech., Jamia Millia Islamia, New Delhi. Mini S. Thomas received the prestigious 'Career Award' for young teachers, instituted by AICTE, Govt. of India, for the year 1999. She has published over 20 papers in International/National Journals & conferences. Her current research interests are in SCADA/EMS systems and intelligent protection of power systems. Parmod Kumar has received his B.E., M.E., and Ph.D in the year 72,75 and 1982 respectively. After post-graduation in Measurement and Instrumentation, he joined M.P.Electricity board, M.P. (INDIA), as assistant Engineer and commissioned telemetry and SCADA instruments at sub-station, power stations and central control room. In 1983, he joined central electricity authority as a Deputy System Engineer and designed and configured the load dispatch centers for electric utilities. Subsequently, he served on various capacities to Indian Railway Construction Company, ERCON, ESPL, ESTC, and then entered in academic life in 1991. His area of interest is smart and intelligent system design, operation and control.

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Communication Infrastructure in CESC Ltd. for Automation of Distribution Management (Existing Practice & Emerging Prospects) Joy Bhattacharya Dy. Manager, Testing Department

Subir Datta Sr. Engineer, Testing Department

Introduction : CESC Ltd. is a century old power utility, engaged in Generation and Distribution of power in and around the twin cities of Kolkata and Howrah. Presently CESC caters to a total of 1.88 million consumers distributed over a license area of 567 Sq. Km. There are 4 Generating Stations with a total installed Generation capacity of 1005 MW. The maximum peak demand for power distribution is 1281 MW which is met by importing additional power from WBSEB. The power Distribution network consists of 75 nos. Substations and more than 3000 Distribution Transformers. There are 6 No. Regional Offices and 38 No. Cash Offices. The entire license area of operation has been divided into 10 No. Engineering Districts and 70 No. Commercial Revenue Districts.

Distribution Management : The growth of Power Distribution network in our country has not been satisfactory primarily because of inadequate investment. The only way for utilities to maintain a sustained growth is to ensure profitability. Reforms in Power Sector has thrown further challenges to the Utilities by providing more choice and flexibility to the Consumers. Proactive Cost Control and reduction/control of Distribution Loss are the key areas to achieve profit. As Distribution is the interface between the Utility and its Consumers, an efficient Distribution Management is of paramount importance. Distribution Management in Power utilities is essentially an integration of the following processes: 1. Automation of Power Distribution Network (SCADA/EMS) 2. Control of Distribution Loss 3. Customer Relationship Management For achieving the above, a reliable & modern Communication infrastructure is necessary for exchange of information amongst the above three processes. This paper presents a brief overview of the practices followed by CESC for Distribution Management during the last decade with special emphasis on the communication infrastructure. It also portrays various emerging prospects in similar field.

PART I- EXISTING PRACTICE A.1 Automation of Power Distribution Network (SCADA/EMS) For efficient load generation management, automation of Power Distribution network using Supervisory Control & Data Acquisition System (SCADA) has become a necessity. Data acquisition systems are installed at relevant stations and outputs of which are transported to Controlling centres where decision making is made based on actual parameters and not on perception. The existing SCADA systems deployed in the automation of our Power Distribution Network have the following near real-time monitoring and Control functions.

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• • • • • •

Monitoring and control of 132kV/ 33 kV systems Control and monitoring of 11 kV/6 kV distribution network Control and monitoring of HV consumers. Load study and its trends. Control of reactive loading. Demand monitoring

In our organization two different type of SCADA systems coexist (i) Point to Multipoint (ii) Point to Point 1. Point to Multipoint SCADA for Central Load Dispatch Centre For monitoring and control of 33 kV and higher Voltage level Power network, a modern, state of the art SCADA system is in place since 1996. There are 16 Remote Terminal Units (RTU) located at HV Substations and Generating Stations distributed in and around our licensed area of operation. All the RTUs process Power system information (Analog - MW, MVAR, AMPS, Hz., kV & Digital Circuit Breaker, Isolator) and send the processed data to the Central Load Dispatch Centre over reliable communication channels with 1 + 2 redundancy. At the Control end processed information from all RTUs are captured and mapped in mimic displays. Central Station : The major components of the Central Station are:(i) Tele Control Interface (TCI)- This is the interface to all RTUs. All RTU Channels are terminated here. (ii) Tele Control Servers - A group of SUN( SOLARIS) Servers running the proprietary application software process the data from the TCI. (iii) Man Machine Interface : These are basically SUN (SOLARIS) servers running the Graphics User Interface for the Control System Operators. (iv) Tele control LAN : This is basically a Ethernet network for interconnection among TCI, Tele Control servers, MMIs and other MIS Servers. (v) MOSAIC PANEL : A Giant wall Mimic of the entire Power Network. RTU : Remote terminal unit at a Substation consists of the following components (i) (ii) (iii) (iv)

(v)

RTU Rack : This is the basic hardware where all field information are terminated. It runs an embedded proprietary software. Transducers : They are distributed in all control panels and provide analog measurands (MW, MVAR, I, kV, Hz., Transformer Tap position etc.) to the RTU Rack. Interposing Relays : For transfer of digital field information from/to Circuit Breakers and Isolators to the RTU Rack. MDF (Marshalling Distribution Frame) : This is basically an interface consisting of an array of terminal blocks for proper wiring of field wires to the RTU Rack. This also serves as an isolation or access point for maintenance engineers. DVU (Digital Visualization Unit) : This is a PC connected to the RTU for local control and graphical display of the Substation information.

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A schematic arrangement of the SCADA system is shown below.

2. Point to Point SCADA for unmanned Substations (11 kV / 6 kV) Though all our earlier Distribution Stations were manned, stations which have come up during the last 5 to 6 years are all unmanned. Also, some of the existing manned stations are now being converted to unmanned because of cost control requirements. The Point to Point SCADA system was developed in-house for monitoring and controlling 11 kV / 6 kV unmanned Distribution Stations from a nearby manned Substation. Presently 25 such systems are operational. Over the years the above systems have also undergone changes in design to accommodate additional features, improve reliability and reduce cost. Evolution of the in-house design: 1.

Primary Design: The first few systems were centralized rack-based, i.e. they used PLC-type CPU and I/O interface cards at both manned & unmanned stations with a hard-wired Mimic Panel at the manned end.

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2. Intermediate Design: The Rack and the Mimic panel at the manned end were replaced by a PC with appropriate software for Man-Machine-Interface.

3. Existing Design: The Centralized Rack based Remote Terminal Unit (RTU) was replaced with a distributed architecture using low cost Intelligent Electronic Devices (IED)

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A.2 CONTROL OF DISTRIBUTION LOSS Distribution Loss is classified under three categories namely, (a) Technical (b) Commercial and (c) Theft & Pilferage. 1.

Technical Loss - Mainly attributed to distribution network hardware namely Transformers, Cables, Overhead lines etc. By proper planning, augmentation and selection of equipment this can be minimized.

2.

Commercial Loss - This is mainly on account of Meter quality and Billing errors. Metering technology has undergone a radical change with the induction of Microprocessor controlled Static meters to replace the Electromechanical Meters for both HV and bulk LV consumers. These static meters can be programmed as per existing tariff structure to record energy consumption. They can also record consumption pattern, maximum demand, limit crossing etc. All the recorded data can be downloaded from these meters through its communication port by an instrument called Meter Reading Instrument (MRI). By introducing the above superior quality meters and new billing software, the metering and billing errors have been reduced.

3.

Theft and Pilferage-

To reduce the above loss ‘Power Loss Audit’ and ‘Loss Control’ Cells were introduced. The basic task of these cells are: · Consumption Pattern Study · Pilferage Detection & Disconnection For proper functioning of these cells the essential requirement is proper coordination between various departments e.g. Commercial, Engineering, legal and other legislative & state machinery for which a very reliable communication infrastructure for Voice & data is required. With the development of our corporate Voice & Data networks as discussed later, the operational efficiency of the above cells have been remarkable.

A sustained achievement in reduction of Distribution Loss is graphically shown below. A.3 CRM (CUSTOMER RELATIONSHIP MANAGEMENT) : Like any other business, Consumers are located at the focus of the entire business process of Power Utilities. The basic criterion of achieving Business excellence is to satisfy its Customers. Customer relationship management therefore plays a vital role towards this end. Customer 141

satisfaction process starts right from registration of a Customer and continues through delivery of uninterrupted & quality power, proper billing, quick restoration of breakdowns and value added services (CRES, CESC Website wherein monthly bills can be checked by consumers) etc. The following systems are presently in practice for enhancement of Customer satisfaction : ·

CALL CENTRE - to address issues related to availability of supply namely breakdown, accident etc. The information network used for this operation is explained later.

·

3-Tier CONSUMER GRIEVANCE CELL – A three tier grievance cell introduced to address commercial issues. The information network used for this operation is explained later.

·

QUALITY MANAGEMENT SYSTEM ( ISO 9001:2000 ) : QMS has already been implemented in many of the Departments. It is an effective tool for standardization of work process, continual improvement and takes the measurement of Customer satisfaction & perception as feedback to the system input.

B. COMMUNICATION INFRASTRUCTURE Modern distribution system demands rapid and reliable information exchange among Generating stations, Substations, Load Dispatch Centre, Engineering offices, Commercial offices, Loss Control Cell etc.. A modern state of the art Communication network is therefore absolutely essential to provide pipelines for transfer of information (both voice and data) for the above requirements. Towards this end, CESC Limited has developed a large Telecommunication and Networking infrastructure of its own which has been commissioned and is being maintained round the clock by a group of well-trained professionals. With the induction of various latest technologies the following different types of Communication systems are available. B.1 Point to Multipoint TDM/TDMA Microwave Communication system With the growing demand for increasing quality, reliability and speed of communication the process of migration from old analog systems via copper media to modern digital state of the art communication system started in the early nineties. In the first phase a point to multipoint Digital Microwave Radio system based on TDM/TDMA technology in 2 GHz. band of radio frequency spectrum was installed. The system consists of:(i) (ii) (iii) (iv)

1 No. Central Station including Radio Equipment, Control Modules and Voice/Data Traffic Channel modules. 26 Nos. Outstation equipment with Radio equipment, Control Module and Voice/data Traffic Channel module. 1 No. Omni-directional Antenna at the Roof Top of Central Station, i.e. CESC House. Grid Parabolic reflector Antenna of different sizes at different outstations located at different offices, Generating Stations, Substations & Distribution Stations.

The entire network is managed, configured & monitored from a Network management System (NMS). A schematic diagram of the entire system is shown below.

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B.2 Optical Fibre Communication Network Essence of Optical fibre Communication was felt in our organization during the early nineties because of the following reasons (i) (ii) (iii)

High Bandwidth required for transportation of increasing volume of voice traffic Development of Corporate Data Network Reliability of Communication

Around 200 km length of Optical Fibre Cable has been laid connecting 40 nodes including almost all our important Offices, Generating Stations, Substations and some of the Distribution stations. Major portion of the O.F. cable is underground directly buried type and in few cases Over Head Cables have also been used. Laying, Splicing and termination of Optical Fibre Cables are carried our by our own group of skilled, trained personnel using our own set-up and equipment. The major hardware equipment used to set-up this Optical Fibre Communication Network are :(i) (ii) (iii) (iv)

Optical Line Terminal equipment (OLTE - Single Mode,1310 nm wavelength) Digital Higher Order Multiplexer (upto E3 level- 34.368 Mbps) Primary Multiplexer (E1 level- 2.048 Mbps) IP based Data Switching equipment e.g. Layer-3 and Layer-2 Switches.

Equipment of different types & makes are installed. They are integrated to meet our traffic requirement. For each system, there are NMS for monitoring, configuration and testing of various Network components from the Communication Control Centre. A schematic presentation of a sample O.F. communication Link is shown below.

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Optical Line Terminal Equipment (OLTE) - It converts the 34 Mbps Electrical signal to Optical signal. Higher Order Multiplexer (HOM) - Digitally multiplex 16 nos. E1 (2.048 Mbps) PCM input signals from E1 Multiplexer and the output is 34.368 Mbps (E3) electrical signal. 30 Channel PCM MUX - Primary level Digital multiplexer which multiplexes 30 nos. of Voice and/ or Data channels and the output is E1 (2.048 Mbps) digital signal. Straight Joint Closure - Underground Joint Closure for straight jointing of O.F. cable in the run. Terminal Joint Box (TJB)- Joint Box for termination of O.F. cable at a terminal station. Fibre Distribution Frame (FDF)- Distribution frame mounted with suitable adaptor for interconnection between equipment and fibre. At one end of the adaptor, pigtails (with connector at one end and bare fibre in the other end) from TJB are connected and at the other end Patch cords (with connectors at both ends) from equipment are connected. The Microwave & Optical fibre based transmission systems enabled the transportation of the following services. 1. Corporate Telephone Network : The heart of the Corporate Voice network is a high capacity Voice Switch located at the Corporate Head office which is also the Central Load Dispatch Centre. Around 250 extension lines (Telephone and FAX) are distributed at Engineering and Commercial offices, Substations, Distribution Stations, Regional Depots etc. located at various geographical locations. Moreover, small capacity voice switches at the above locations are linked with the Central Switch to form an integrated omnipresent Corporate Voice network. The same is schematically shown below.

2.

Data Network for SCADA

(a)

For Point to Multipoint SCADA system, to improve reliability, three different media (1 active + 2 stand-by), namely Microwave, Optical Fibre and copper Cable are available to transport data from a RTU to the Central Load Dispatch Station. The Data is serial (RS 232C) having a format of 1200(baud), Odd (Parity), 8 (bits) and 1 (stop bit).

(b)

For Point to Point SCADA, two options namely copper Cable or Optical Fibre are used for transportation of data. The format of the serial (RS 232C) Data is 9600(baud), None (Parity), 8 (bits) and 1 (stop bit).

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3.

Corporate Data Network

With the induction of latest Information Technology applications in various business processes and to keep pace with sustained growth & modernisation, flow of information between various units of the organisation is absolutely essential. A Corporate data network has been developed in this respect which has deployed the latest technological advances in networking in different phases. Migration from low speed copper cable based data links to a Packet Switched Data network (X.25 protocol based) started from early nineties. The network is schematically shown below. C E S C D A T A N E T W O R K T O P O L O G Y -- S T A R

PA D

PA D

PSE

PA D

PA D

X .2 5 P A C K E T - S W IT C H N E T W O R K C L O U D

An X. 25 Switch located at the Corporate office have a no. of network ports which are connected to remote station equipment. At the remote nodes i.e. at our different Regional Offices, Engineering Offices and IT centre, Packet Assembler Disassembler (PAD) equipment are installed. Network Port of all these PADs are connected to the network ports of the Central Switch over Microwave and Optical Fibre system. Computers at the nodal offices are connected to the serial ports of the PADs. Few serial ports of the Regional Office Servers are also connected to the PAD ports. Two different types of connection as mentioned below are deployed depending upon the requirement. (a) Switched Virtual Circuit (SVC) : (i) (ii)

For accessing the Regional Office Servers from Computers located at different offices. IP based applications are also supported over this serial connection by using Point to Point Protocol. The main application is File Transfer among different host machines in simultaneous multiple sessions.

(b) Permanent Virtual Circuit (PVC) : This is a permanent point to point connection between two computers for dedicated, secured file transfer operation. The interconnection of the X.25 Data Network with the carrier system (Microwave Network) is shown below.

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4. Corporate Intranet (CESCNET) : With the rapid & diversified developments in the field of Information Technology, different wings/ departments in our organisation developed & customised their own local area networks (LAN) platforms to meet their specific requirement. With the growing complexity for such heterogeneous application platforms, inter office transaction of data became a very difficult task and the urgency for migration to a convergent solution was felt. Towards this end, a TCP/IP based network (CESCNET) was proposed to integrate the islanded sub-networks without sacrificing the specific application requirements. CESCNET is basically a Corporate Intranet and presently supports the following services. (i) (ii) (iii) (iv) (v) (vi)

e-Mail ERP Consumer query System Call centre operation Interoffice transaction of data Internet Access Service.

Network : While designing the CESCNET, all the following key factors related to a modern, efficient network were considered. (i) (ii) (iii) (iv) (v) (vi)

Modularity Scalability Upgradability Security Redundancy and last but not the least Management

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At the heart of the network, there is Layer 3 Switch with a backbone data transfer capacity of Gigabits per second. There are a number of network ports of which some are optical and the rest are electrical. The Optical Ports have been extended to the different nodal centres (Layer 2 switches), to form a star network topology in Tier 1. Subsequent distribution down the line has a tree/branch topology to cover all existing establishments. There are 36 nodal centres in the CESCNET with around 800 Client machines connected. Servers : The following servers of CESCNET are located at CESC House and are directly connected to the Electrical Ports of the Layer 3 Switch. All Servers of CESCNET run on LINUX Platform which has become very popular for different Corporate networks because of its powerful, versatile networking options with strong security features. Moreover, using LINUX is also very cost effective. (i)

(ii)

(iii) (iv)

Central Database Server - containing the entire Consumer database & running applications for Consumer Query System & Call Centre. All applications are browser based and developed using PHP4 and the RDBMS used is MySQL. Both these software are freeware. E-Mail Server - This is the Corporate e-Mail server based on Q-Mail which is a also a freeware. All the users of CESCNET can send and receive e-Mails to/from Internet by means of this Server via our Internet Server. For this facility access to the Internet is not required. DHCP Server - This is responsible for generation & allocation of Network IP addresses to the Client machines across the network. PROXY Server : This is the interface between the Internet and CESCNET and maintains the various selected Internet accounts for specific Users.

A schematic representation of CESCNET is shown below:

147

V-LAN (Virtual LAN) : Virtual LAN is an environment where different Client machines of a particular wing/department installed at different locations and connected to different nodes form a functional and logical Local area Network as if all the Clients are co-located . This concept has found immense application in our system where a wing (e.g. Substations, Commercial etc.) has different point of presence distributed within our licensed area of distribution for operational requirements. Since the entire CESCNET is based on a single vendor hardware, the VTP (V-LAN Trunking Protocol) has been used to support switching of V-LAN packets. CALL CENTRE NETWORK For automatic management of Consumer calls, a Call Centre Network has been formed. A 10 seat Call centre facility from an existing paging service provider has been hired. The Call Centre is one of the nodal points of our CESCNET where 11 nos. client machines are installed ( 1 no. for CESC attendant). 15 Nos. BSNL lines with an unique 4 Digit toll free Telephone number in hunting mode are terminated to the local EPABX. An Interactive Voice Recorder (IVR) is also installed to support the Consumer when all the attendants are busy. The different Regional Depots, which are also CESCNET nodes, form an integral part of this Call Centre Network. A schematic of the network is shown below.

148

B.3 VHF RADIO COMMUNICATION SYSTEM VHF wireless radios were the principal means for exchange of voice information in the early days. Though with the advent of modern digital communication technologies there has been a revolutionary change in the choice and pattern of information exchange, VHF wireless radios still play a very vital and cost effective means for providing communication solutions for · · ·

Back-up against any catastrophic failure of the modern communication systems Power system Field Operation Mobile fault Restoration Vehicles.

Apart from the above, the latest microprocessor based synthesized VHF Radio sets are deployed in our unmanned Distribution stations to Transfer alarm contacts to the Central Load Dispatch Centre against specific events e.g. tripping of Feeder, Transformer. Auxiliary NC contacts from all tripping Relays in the unmanned Distribution Station are wired in a series circuit. In case of any tripping, the circuit opens which is sensed by the VHF Radio and accordingly it sends an alarm to the Master Set at the Central Load Dispatch Centre by way of an audible alarm along with a display of the identity of the sending set. B.4 GSM MOBILE PHONES IN CLOSED USER GROUP Introduction of Mobile Telephones have added pace to every Business process. For utilities where the talk time for operational and administrative requirements is very high, free usage of Mobile phones as per normal tariff plans are not cost effective. Closed User Group concept which provides unlimited talk time between users of a group have enabled cost effective means of carrying out communication in our organization. Operational/Maintenance personnel who carry out field work utilize the above facility to great advantage round the clock. As of date 133 Nos. General Users are registered under the CUG who can make unlimited 2-way communications among themselves and receive call from any caller (from both PSTN & Cellular) beyond the CUG. 15 nos. Super Users are also included in the CUG who enjoy all service provisions in a normal Mobile Phone. PART II - EMERGING PROSPECTS A. Integration of SCADA system with GSM network With the introduction of GPRS (General Packet Radio Service) technology in the GSM Cellular network, integration of our SCADA systems with the GPRS Server may be a reality in the near future. This system will update our CUG users on a real time basis with Power system information through SMS (Short Message Service). This is schematically shown below.

149

B. DISTRIBUTION AUTOMATION SYSTEM (DAS) : Apart from the benefits of our existing SCADA/EMS system ,as described earlier, other important aspects of an effective DAS are: Power Quality : · Near real time monitoring of electrical parameters, waveforms/harmonics and other disturbances at Substations & Distribution network. · Close monitoring of reactive power and automatic switching of Capacitor Bank. Operational Efficiency : · Real time monitoring, supervision and control reduces response time and network down time. · Reduction of outages by way of implementation of automatic redirection of power network, reclosing of sectionalisers, circuit breakers etc. In order to achieve the above in a power network consisting of equipment/relays/sensors/transducers from different vendors, a convergent standard of communication is required. Utility Communication Architecture (UCA) is the standard for this uniform platform. Utility Communication Architecture (UCA) : Worldwide, electric utility deregulation is expanding and creating demands to integrate, consolidate and disseminate real-time information quickly and accurately within substations. Utilities incur an ever-increasing expenditure for real-time information exchange, system integration and data maintenance. Development and sharing information among all industry participants on critical resources (e.g., critical T&D equipment) is one of the most crucial issues for reliable power systems. In response to this need, IEEE has published a suite of international standards in the “Utility Communications Architecture” (UCA). UCA’s objective is to dramatically improve device data integration into the information and automation technology, reducing the costs for engineering, commissioning, operation, monitoring, 150

diagnostics, asset management, and maintenance and increasing the agility of the whole life cycle of a substation. UCA differs from most previous utility protocols in its use of object models of devices and device components. These models define common data formats, identifiers, and controls, e.g., for substation and feeder devices such as switches, and relays. The models specify standardised behaviour (interoperability) for the most common device functions. The standards applied in UCA (e.g., Ethernet, TCP/IP, and MMS-Manufacturing Message specification IEC 9506) define and exchange real-time data. The UCA models, services, and protocols for substation devices are currently being integrated into the drafts IEC 61850 (Communication networks and systems in substations). The Utility Communications Architecture (UCA) was developed under the sponsorship of the Electric Power Research Institute (EPRI, Palo Alto, USA). The objective of UCA is to provide seamless integration across the utility enterprise using off-the-shelf international standards to reduce costs. UCA Version 2.0 has been published as IEEE technical report TR1550 in November 1999. The UCA documents specify a set of existing international standards, which can be applied to specific communications architectural requirements in the utility industry. UCA can be used to define and implement a wide variety of standards-compliant communications systems such as those required to support Distribution Automation, Demand Side Management, Substations and Control Systems, Power Plant Automation, and Customer Interfaces. The figure below shows the test set-up with the Ethernet communication network connecting all the devices “talking” UCA/IEC 61850.

By providing a common communications protocol stack, UCA IEC 61850 allow utilities and other industries to “plug and play” equipment from different vendors. The interoperability of most important substation devices due to common specification leads to a tremendous cost reduction during engineering, commissioning, operation, asset management, and maintenance. C. REMOTE AUTOMATIC METER READING Remote reading of Microprocessor based Static Meters minimizes the possibility of meter tampering, provides means for remote surveillance and also reduces billing delays. The following methods of Remote Meter Reading are practiced by a few Utilities. RADIO INTERFACE METHOD : Each meter is fitted with one intelligent unit with memory device and Radio interface unit and will transmit all metering information when asked for. These units can be polled from a nearby mobile unit without accessing the Meter. These data can be processed in a centralized location and will be available for carrying out the functions as mentioned above.

151

GSM TECHNOLOGY : The meter is fitted with a GSM smart card (PCMCIA) or a fixed Cellular terminal. From a centralized location, metering Data can be retrieved by polling method using the existing GSM network. DISTRIBUTION LINE CARRIER COMMUNICATION (DLCC) : This is a new emerging technology. Each meter is retrofitted with an extra hardware, which will gather all metering information. A Concentrator unit is connected at the LV side of the Distribution Transformer, which collects and stores all the metering information of its LV network. Communications between the concentrator and the meters take place through Distribution lines. Data stored in the Concentrator can be retrieved by local download or by remote access using radio or GSM techniques. The above three methods are schematically shown below

Conclusion : CESC Limited, in pursuance of its vision to achieve operational efficiency and the ultimate goal of business excellence has consistently tried to reap out the benefits of latest technological advantages in the arena of Communications, SCADA, Networking and Automation. We feel that one of the most effective ways for Utilities to keep themselves informed and updated about the advancements in relevant application area is to share information and ideas with others in the same domain. We sincerely hope that this conference will open up new ideas which will be implemented by the Utilities in future for improvement of their efficiency.

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Estimating Cost of Unreliability for Commercial Customers Dr. Navjot Kaur Punjab School of Management Studies Punjabi University, Patiala

Er. Tejpal Bhatti

Abstract : This paper presents assessment of customer interruption costs for commercial customers in the Indian state of Punjab. These costs would help in planning reliable power systems in the country, as enhancing system reliability would be done objectively by using these costs as a surrogate for value of reliability.

INTRODUCTION In view of the impending restructuring of power industry in India, service reliability of a power system has emerged as a major issue in power industry. In near future as customers would be able to change to an alternative energy supplier in consideration of price, increasing service reliability cannot be considered as a mandatory strategy necessarily. Therefore, to effectively deal with such an issue it is necessary to find out customers’ response to service reliability and interruption costs. In most of the countries of the world, in the past the power industry dealt with the issue of service reliability with focusing on increasing reliability. However, as increasing reliability is accompanied by high costs, implementing flexible plans in consideration of customers should be done in developing countries like India. As improved service reliability brings the reduction of interruption costs, it is possible to carry out an economic evaluation of a system facility plan from the customers’ standpoint by quantifying the interruption costs with some methods. Cost of outages for customers is a key issue in the cost-effective management of electric utilities. For commercial customers, these costs may take the form of lost sales, poorer relationships with customers because of delivery issues, loss of final product or intermediate inputs, lost wages or additional overtime costs or damage to sensitive equipment. While customers want improved reliability, they also want reduced electricity prices. Understanding the nature of this trade-off, which may be different for different categories of business customers, is increasingly important. The importance of reliability may well increase as electricity markets are deregulated and retail competition unfolds. When electric utilities are considering alternative investment portfolios, particularly in a least-cost planning framework, customers’ costs of interruptions are among the costs, which should be examined, in various engineering options. This information can be meaningfully applied to a wide range of areas including transmission line design, substation and distribution circuit design, equipment rating and maintenance schedules.

METHODOLOGY : Customer interruption costs are the economic losses customers experience as a result of power failures. These costs can be evaluated using three approaches-indirect analytical evaluations, case studies of actual blackouts and customer surveys. Results from both analytical methods and the case studies have indicated that cost assessments should obtain information that is customer specific. Customer-specific costs are the losses that various customers experience due to the unavailability of the functions, products and activities that are dependent upon electricity. The best source of this information is customers themselves.

153

In the direct cost method, customers are asked to assign a value to the costs they would incur for an interruption of their electricity supply. Usually customers are given several different scenarios that vary by duration, time of the year and time of day. Customers are also often asked to breakdown the cost incurred into various cost categories. Providing cost breakdowns may produce more accurate estimates. This paper presents the costs obtained by the direct method where customers were asked to estimate the loss to them using different scenarios and also breaking down the cost into various sub-costs. For the present study customer survey method was adopted. Due to economic and resource limitations only commercial organizations were included in this survey. Further this class of customers apart from industrial suffers more losses than any other and is an important sector of the economy. A questionnaire developed by the Power Systems Research Group for their study, ‘Assessment of Reliability Worth in Electric Power Systems in Canada’ in 1993 has been adopted .It was modified and restructured to suit Indian population/conditions. The validity and reliability of the same was established. Customers were asked in the survey to identify their costs on a worst-case basis i.e. to report the costs they would incur as a consequence of an electricity interruption at the worst time of the day, on the worst day of the week in the worst month of the year. The factors contributing to the cost were taken as : Wages paid to idle workers, loss of sales, overtime costs, damage to equipment, spoilage of perishables, cost of running back-up and cost of any special procedures.

Results : The primary purpose of conducting this survey is to establish monetary losses associated with various levels of unreliability. The most direct and usable form of customer perceived interruption costs is the customer damage function. It portrays the costs associated with outages as a function of outage duration. The CDF can be determined for a particular customer category or for an overall sector. It has been calculated for the commercial sector by using aggregated customer costs by the percentage of their load mixes and then summing these costs. Commercial Cost Damage Function :

1000

Cost(Rs/kW)

100

10

20min

1hr

2hrs 4hrs

8hrs

1 1

10

100

1000

Interruption duration(minutes)

Fig. 1: Commercial Cost Damage Function After getting direct cost estimates from all the respondents for durations varying from 1 minute to 8 hours, their connected loads were obtained. The costs provided by each respondent were normalized. As the table indicates for interruption duration of 1 minute the whole sector suffers a 154

loss of Rs. 16.38/kw and Rs. 20.21/kw for an interruption of 20 minutes. This cost rises with increase in interruption duration, it being Rs. 111.15/kw for an interruption of 8 hours. Table 1 COMMERCIAL COST DAMAGE FUNCTION Interruption Duration CDF 1 min. 16.38 20 min. 20.21 1 hour 36.12 2 hours 54.60 4 hours 84.34 8 hours 111.15 The expected accuracy of the derived customer damage function will improve as the representation of the customer mix in terms of customer type etc. more nearly represents the service area in question. . If similar cost profiles for other sectors, i.e. industrial, agricultural and domestic are obtained, these can provide a composite cost damage function not only for Punjab but also for other states in the country. The CCDF is an estimate of the costs as a function of the interruption duration for the customer mix in the service area of interest. CCDF can be converted to an Interrupted Energy Assessment Rate (IEAR) in order to incorporate the customer costs in planning further studies. The approach has already been used in many countries. These outage cost profiles can be used in the system planning and decision-making. This would help in undertaking cost benefit analysis to develop better power supply systems. Some electric utility customers experience significant economic losses whenever there is a power interruption. These customers need and expect the highest reliability of service that the utility can supply. To operate efficiently in this situation it is important for the utilities to strike a balance between costs of improving service reliability and the economic benefits that these improvements bring to customers. This type of Value Based Reliability Planning directly takes account of reliability and power quality to customers in assessing the cost effectiveness of proposed investment alternatives. This incorporates customer value of service in the planning process at the time when cost-benefit analysis is undertaken for investment alternatives. This is done by including avoided customer losses (arising due to power interruptions) in benefits that are received from investments to improve reliability BIBLIORAPHY : [1] [2] [3] [4]

[5] [6] [7].

Allan R. and R. Billinton, “Power System Reliability and its Assessment : Part 3, distribution systems and economic considerations”, Power Engineering Journal, August 1993. Wacker, G. and Billinton R., “Customer Cost of electric interruptions”. IEEE Proc.77 (6),1989. Garry Wacker and Garry Tollefson, “Electric Power System Customer Interruption Cost Assessment”, Reliability Engineering and System Safety, (46), 1994. Power System Research Group, “Assessment of Reliability worth in Electric Power Systems in Canada”. Department of Electrical Engineering, University of Saskatchewan, Saskatoon. June 1993. Mark Allen Bernstein and Youseff H(University of Pennsylvania Energy Center), “The Economic Costs of Electricity Shortages: A Case Study of Egypt”. Billinton and M. Pandey, “Customer Interruption Cost Assessment: An International Perspective”, IEEE Power Engineering Review, January 1999. Wacker. E. Wojczynski, R. Billinton, “Cost/Benefit considerations in providing an Adequate Electric Energy Supply”, Third Symposium on Large Engineering Systems, July 1980. 155

SESSION – 4 Regulatory and Legal Issues • Legal Framework : Rights and Obligations of Utility and Customer • Tariff Issues, Subsidy, Cross Subsidy and Economics as affecting the Distribution Business •· Taxation and Duties

Chairman : Sh. C. P. Jain, CMD, National Thermal Power Corporation Ltd.

Key Note Speakers : i)

Sh. Amit Kapoor, J Sagar & Associates ”Legal Framework : Rights and Obligations of Utility and Customer”

ii)

Sh. Sanjeev Aggarwal, CRISIL “Tariff Issues, Subsidy, Cross Subsidy and Economics as affecting the Distribution Business”

iii)

Sh. Y. H. Malegam, SB Billimoria & Co. ”Taxation and Duties”

Additional Papers included in Binders : 1.* “Real Time Operation of Power Systems Under ABT Mechanism : Some Issues While Implementing Within State Grids” By Sh. P. V. Satyaramesh, Dept. of Power Systems APTRANSCO & Dr. C.Radhakrishna, Director & Professor of Elec Engg, UCG Academic Staff College, JNTU, Hyderabad

* Papers received by the time of compilation

Real Time Operation of Power Systems under ABT Mechanism : Some issues while implementing within State Grids P. V. SATYARAMESH Department of Power Systems APTRANSCO, Hyderabad

Dr. C. RADHAKRISHNA Director & Professor of Elec Engg, UCG-Academic Staff college, JNTU, Hyderabad

ABSTRACT The new tariff mechanism called as Availability Based Tariff (ABT) has been implemented in regional grids so as to impose the grid discipline and to regulate the wide fluctuations in the frequency. It came into existence for southern regional grid from 1.1.03 onwards. This paper mainly focuses on the techno economical issues of integrated operations of practical large scale Power System if ABT is introduced at Constituent level within state grids. This paper also enlightens complex issues and variety of critical situations to be handled by the operators of State Load Desptch centers of Transmission companies and of Generating Stations and of Companies of State due the to introduction of new tariff mechanism to the inner layers of the state sector. The Load dispatch operator cannot judge the implications of the operations on Real Time basis under ABT mechanism with various practical constraints prevailing in the existing state grids in minute level and cannot analyze the effect on both the dynamics and economics of the entire power systems. These problems are proposed to be addressed in this paper.

1.

INTRODUCTION

The Southern region of Indian power system network comprises of APTRANSCO, TNEB, KSEB, KEB, and Pondy as independent areas (constituents) and draws their central sector shares from the Central Generating Stations (CGS). These five areas are interlinked as a Single Integrated system through the 400 KV Central Tie Transmission Network. In present situation there are wide frequency fluctuations from rated 50 HZ, experienced by this integrated power system since wide gap between generation and load exists. These frequency variations tend to cause serious damages to both generator and loads. Now CERC has notified AVAILABILTY BASED TARIFF (ABT) to be implemented for Southern Region from 1-1-2003 onwards. According to this, flow from or into the control areas other than the schedules are to be priced linked with frequency. The over drawn control area has to pay @ Rs 420 for the frequency below 49 Hz and Rs 0 for the frequency above 50.5Hz and linear in between with 0.02 Hz/step, to the under drawn control area. ABT mechanism has been implemented on regional basis over the national level. It mainly facilitates the Grid discipline, trading in capacity and energy and merit order despatch as and when made effective. The distinctive features of the proposed ABT is to overcome the serious problems related to (i) Low frequency (48.0-48.5 Hz) during peak Load hours (ii) high frequency (50.5-51 Hz) during off peak hours (iii) rapid & wide changes in frequency -i.e. 1 Hz change in 5 to 10 minutes prevailing many hours every day.

2.

PHILOSOPHY OF AVAILABILITY BASED TARIFF

The Availability Based Tariff is combination of frequency based Tariff (Drawals VS frequency) and Reactive power based Tariff (Reactive Power (VS) Voltage). The components are given as follows (I) (1)

PRICING FOR ACTIVE POWER Capacity charges based on target availability - Full Fixed charges at an availability of 80% in case of NTPC and 72% in case of NLC 157

(2) (3)

Energy charges for the energy scheduled - Variable Cost Unscheduled Interchange (UI) charge of 0-420 ps According to variations in each time block Ps/Unit. Of 15 mts. duration Scheduled energy w.r.t. Frequency (UI)

(II)

PRICING FOR REACTIVE POWER

Payable for reactive power drawls at the Rate of 4 paise per KVAh for voltages below 97%. Received for reactive power injections at the Rate of 4 paise per KVAh for voltages below 97%. Payable for reactive power Injections at the Rate of 4 paise per KVAh for voltages above 103%. Received for reactive power drawals at the Rate of 4 paise per KVAh for voltages above 103%. No mention is made in the IEGC regarding compensation for reactive power drawal at Generating Stations.

3.

MOTIVATION FOR INTRODUTION OF AVAILABLITY BASED TARIFF

There are large deviations in frequency from the rated frequency of 50.0 Hz .Low frequency situation results when the total generation is less than the consumer load connected during the peak hours. High frequency is a result of insufficient backing down of generation when the total consumer load comes down during off-peak hours. The pre-ABT mechanism tariff did not have incentive for either backing down the generation during off- peak hours or for reducing the consumer load /enhancing the generation during peak-load hours. In fact, there is a financial advantage today in going on generating at a high level even when the consumer demand has come down .In other words, the present tariff mechanism (ABT) encourages grid discipline. The Availability Tariff would directly address these issues. Firstly, by giving incentives for enhancing the output capability of the power plants, it would enable more consumer load to be met during peak load hours, Secondly, backing down during off–peak hours would not result in a financial loss to the generating station, and therefore the present incentive for not backing down and raising the system frequency would get neutralized. Thirdly, the shares of beneficiaries in the Central generating stations would be given a significant meaning, which has not been there so far. The beneficiaries would have been well-defined entitlements, and they would be able to draw power up to this at normal rates of the respective power plants. In case of over-drawls, they would have to pay at a high rate during peak load hours, which should discourage them from overdrawing and pulling down the frequency. This payment would go to the beneficiaries who received less energy than was scheduled.

4.

Issues to be handled in the existing methods of implementation of ABT within the states and its companies.

The basic practical constraints to be encountered in power systems due to implementation of ABT within states and its companies are listed out below. (A) (I)

CENTER GENERATING STATIONS CGS UNITS

(1)

It is found that penalty on over generation in the frequency band i.e. in between 50 and 50.5 is not same for all CGS generators as the variable cost of cgs units are different. This means even if schedule is deviated by some of CGS Units above 50Hz, they are benefited instead of getting the penalty. It seems to be these penalties are not same for all cgs generating units.

158

(II)

REACTIVE POWER

(2)

The Southern Region has mainly four constituents viz. A.P, KRANATAKA, KERALA, TAMILANADU, GOA. It means that the system is operated as an integrated mode with four areas. If an area does not have sufficient transmission network for handling the power, there may be overloading of lines and transformers which in turn causes heavy absorption of Reactive power and Voltage drops. This affects the other areas even if they have better transmission network and VAR compensation. It compels the above areas to draw VAR due to these voltage drops and overloading of lines and transformers in the said area. These results the other areas also become responsible for payment for the Reactive Power due to inconsistent area.

(3)

It is also not mentioned about the Reactive power generation at 103 % of voltage or absorption at 97 % of voltage of Generating Stations. The generator also plays vital role in reactive power supplements/absorptions. It can deliver only active power without giving the sufficient support of reactive power. It means that the generator will try to get more income by maximizing active power scheduling by depriving the reactive power.

(III)

CENTRAL TRANSMISSION NETOWRK

(4)

The Unscheduled interchange due the transmission constraints (i.e. due to break downs of CTU lines) are not properly not defined in this ABT SCHEME. This means that any outage of CTU line will contribute the losses and unscheduled interchange.

(B)

Constituents

(I)

General

(a)

Software Tools

(1)

Use of validated software is to be provided for checking the correctness of the regional accounts prepared by SRLDC / SREB and also for the accounts prepared by constituent which are to be passed on to their DISCOMS.

(2)

The Discom Companies must be supported by the Load Management and Load staggering and Load shedding Soft wares so as to predict the Load patterns with imposing the various practical constraints prevailing in their systems.

(b)

Losses

(3)

A special tool to study the line loses with scenarios must be provided to the State Load Despatcher as energy losses become predominate role in the state sector. This means that the transmission networks and distribution networks are to be reconfigured dynamically so as to achieve better voltages and reduce losses by conducting load flow studies in both state level and companies level parallely by simulating the different scenarios.

(4)

The commercial losses due the theft of energy which predominately prevailing in the State Sector are taken into consideration properly while introduction of ABT within states and their companies.

159

(II)

Generating Stations

(5)

Incentives if any will be considered for any particular station must be defined properly. A suitable mechanism must be developed so as to pass the incentives/penalties of ABT to the Apgenco/Discoms by APTRANSCO.

(6)

Purchasing of Energy from Generating Stations of the individual Stations (Genco) Participation of each Unit in ABT must be evolved. This means parameters such as its heat rates which are effecting the individual unit variable cost

(7)

The variable cost of unit must be accommodated properly in the charges of Un scheduled Interchanges of ABT at different frequencies (the capacity charges already paid to the generating stations) as the variable cost of unit in the constituents spreads from 2rs/unit to 84paisa/unit. This means a suitable characteristic must be found to accommodate drastic variation in variable charges.

(8)

The Proper Hydro and Thermal mix must be arrived during preparing the Schedules.

(c)

Hydro Scheduling

(9)

Procedure of Scheduling of Hydro energy during surplus and non- surplus times by giving priorities to Irrigation on Real Time basis must be evolved. i.e. the scheduling the hydel power must be done by considering the different scenarios of drought, normal and flood conditions and irrigation constraints prevailing in the state sector.

(10)

Definition of Release of water through machine for irrigation should be evolved properly. This means that they are to be treated as must run units while scheduling the hydro component.

(11)

It is to make provision for the pumped storage units of GENCO by encouraging them for overdrawing free CGS power at high frequencies through their transmission Networks. This means when the frequency is above 50.5 Hz, any over drawl of energy from the central generating units is at free of cost. This energy can be properly utilized for pumping the water back during the high frequencies so as to secure the system from collapses due to high frequencies and to conserve the energy. The vallies are also be properly adjusted by using non-peak energies for pumped storages.

(d)

Thermal Scheduling

(12)

All thermal units are to be treated as base load stations. During high frequency periods each machine should run with a minimum spinning reserve of at least 5% of the machine capacity which can be utilized during peek load condition Exception to small units such as NTS.

(13)

The proper backing down of thermal units should be evaluated because every thermal unit has its own technical limits of operation .The backing down of generation will increase the auxiliary consumption percentage and heat rate of the station which in turn reflect on the increase of the variable cost of unit even if the backing down without oil support is given. Thermal units run with oil support, must be given on Real Time basis.

(14)

Closure of thermal units for a short period is not advisable since they take more time to get back into service and also it is a costly affair.

160

(e)

Gas Stations Scheduling

(15)

Provision must be given to the dispatch instructions for backing down of units of IPPS operating under constituents. Since IPP agreement stipulates that dispatch instruction (GVK @SPECTRAM) can be given for a time period (1600 @ 1200 hours/tariff year) and specified no of dispatch instructions per day. IPP is eligible for either deemed generation or notional generation depending on PLF due to dispatching instruction to the units for backing down. While closure of units can be given to IPP. They can be getting back into service at a very short notice. It means

(11)

Running on IPPs units on naphtha is costlier. The Procedure for Dispatch instructions for backing down of units using naphtha must be defined properly on real time basis. During non-availability of gas permission to run on naphtha may be defined. (i.e. rejection).

(12)

Non-conventional units participation must be properly defined on real time power system operation.

(13)

Agreements with some captive power plants or IPP such as VSS, BSES etc., to run them as must run condition how to honor them must be defined.

(14)

As there are different date of commercial operations for the IPPS, it must be evolved for a suitable procedure them. The dates of commercial operations of the gas unit are different in the state sector. The incentives are linked with the PLFs. It is required to stagger the scheduling of IPPS power.

(15)

The Evaluation of Notional Incentives and Deemed generation for the IPPs by taking PLF, as base must be defined properly in the implementation of ABT as already entered into an agreement.

(III)

Technical Constraints

(16)

Technically required units that are giving the security to the grid and better voltage improvements to be identified properly and they should not be ordered for closure.

(17)

The Role of Constituents Transmission network in the ABT for their contribution.

(18)

The Proper tools must be developed for carrying out the Merit Order Despatch by simulating all practical conditions prevailing in the present power system grids.

(IV)

Reactive Power

(19)

The Reactive power drawls/injections of Distribution companies must be properly evolved as agriculture component predominately plays a major role.

(20)

The scope of Allotment of power to the agricultural power in the different periods must be defined how to implement of ABT in State Sector.

(V)

Billing Methodologies

(21)

The proper billing methodologies must be evolved for the drawals and unscheduled interchanges between the companies.

161

(VI)

Real Time Operation

(22)

Suitable Communication Networks to be established in-between APTRANSCO and Discoms and within Discoms.

(23)

The Real Time SCADA has to be planned up to 132 kV by APTRANSCO as TRANSCO has covered the SCADA only up to 220kV and some Discoms has only from below 33 kV. There must be a need to integrate of SCADA systems Of APTRANSCO and SCADA systems of Discoms.

(24)

The Boundary Points for drawl/injections of the power for the DISCOMS needed to specify accurately, as the commercial impacts are more.

5.

Conclusions

Composite scheme is to be evolved to fix up for evaluating the various constraints encountering during real time operation of power system and its control under ABT Mechanism. Furthermore, Mathematical Model will have to be developed by simulating these power systems while operated under ABT mechanism by imposing all the various practical constraints. Also it is to be analyzed their effects on dynamics and economics of the power systems on real time basis. It is also needed to provide infrastructral facilities for monitoring system under the ABT. The issues here need focused attention while implementing within the state grids under ABT mechanism. References : (1)

Various papers circulated and presentations to utilities by Shri Bhanu Bhushan, Director (Operation), Power Grid.

(2)

Purchase Agreements between Spectrum Power Generation Limited and Andhra Pradesh State Electricity Board dated as of 23 rd Jan 1997.

ACKNOWLDGEMENT The Views expressed in this paper are of the authors in their individual capacity and not necessarily that of APTRANSCO of Andhra Pradesh.

162

SESSION – 5 HR STRATEGIES • Decentralisation of Responsibilities with Authority and Accountability • Franchisees in Rural and suburban Areas

Chairman : Sh. Firdose Vandrevala, MD, Tata Power Co. Ltd./ Sh. R. K. Narayan, Ex CMD PGCIL, UPCL and Senior Advisor NDPL

Key Note Speakers : i)

Sh. K. K. Sinha, Director (HR), NTPC “HR Strategies for Competitiveness”

ii)

Major General B. K. Bhatia, Advisor - HR, NDPL “Performance Management : A Tool For Organizational Effectiveness”

iii)

Sh. Saurav Das Patnaik, Mercer HR Consulting, LLC ”Decentralization of Responsibilities with Authority and Accountability”

Additional Papers included in Binders : 1.* “Planning of Distribution System - A case study of Rural Electrification” Sh. S. Majumdar, ED, Sh. I. S. Jha, GM & Sh. Rakesh Kumar, Chief Manager, PGCIL

* Papers received by the time of compilation

163

Planning of Distribution System A Case study of Rural Electrification S. Majumdar ED (DMS)

I. S. Jha GM (DMS)

Rakesh Kumar Chief Manager (DMS)

Power Grid Corporation of India Limited, Gurgaon, Haryana 1. PREFACE Planning criteria of Transmission and Distribution System sets the performance requirements of the system as a whole as distinct from design criteria, which determine the performance of individual components. The main objective of planning is optimum expansion of the system to meet its present and the growing load demands. The primary factors governing the distribution system planning are: (i) Quality (ii) Reliability (iii) Economy 1.1 QUALITY OF SUPPLY Extensive use of sophisticated electrical gadgets like air conditioners, refrigerators, and computers together with industrialization has made it incumbent for electricity supply utilities to maintain the voltage variation within very stringent limits. Indian Electricity Rules provide for maximum and minimum limits of voltage variation to be ensured by the electricity supply organizations at the customer’s premises. 1.1.1

Voltage Regulation

Rule 54 of the Indian Electricity Rules, 1956 lays down the permissible limits of voltage variation as follows. Rated Voltage(V) 250-650 650-33000

Declared Voltage 230/400 V 11000/33000 V

Maximum Permissible Variation ± 6% + 6% /-9%

1.1.2 Frequency Frequency is another aspect of the quality of supply. Statutory variation on frequency allowed is + or – 1.5%. Actual variation has been found to be much more. While the distribution profit centers have no control over the frequency it can at best request Regional Electricity Board to enforce grid discipline to ensure that the frequency is within the permissible limits. 1.1.3 Harmonics Presence of voltage and current harmonics is other parameters which has not been given much attention till now. Harmonics causes losses in equipments and reduce the life of equipments. The source of harmonics is the AC/DC converters and non linear loads. 1.2

RELIABILITY

Reliability or the standard of service aspect of the supply is the most important item in planning consideration. Reliability of supply however costs money. The higher the level of reliability, the higher is the cost. A reasonable balance should however, be struck between economy and reliability. 164

1.3

ECONOMY

It is indicated in the recent studies that the average energy losses in the power delivery transmission and distribution system are approaching 27 percent or more. These losses should normally be below 15%. Proper economy can be achieved with reduced losses as they shall substantially reduce, the operation and maintenance cost and with additional revenues, make the investment financially viable. 2.0

DISTRIBUTION SYSTEM PLANNING ISSUES

2.1

LINES

Lines can be planned in different configurations i.e. (i) (ii) (iii)

Radial configuration Ring configuration Mesh or interconnected configuration

While the radial configuration is the most economical, it is the least reliable. At present the 11 kV systems are in radial formation except in some of the urban areas. Long time is taken for restoration of supply in case of occurrence of faults in the radial configuration. The fault affects a large area and segregation of fault and restoration of supply even in the unaffected areas is not possible till the fault is repaired which may take a long time. A better system is the ring system where in case of fault anywhere in the ring, supply can be restored from the other end of the ring. The mesh or interconnected system is the most reliable as supply can be restored even in case of multiple faults but it is the most expensive system and normally adopted for the EHV systems only. Economic loading of conductors and underground cables is much lower than thermal ratings and provides a useful guide in establishing an optimum design of distribution lines. However, lower permissible loads make the distribution system very capital intensive. In order to strike a reasonable balance between optimum design and the overall cost the loading on overhead lines should be restrained to 70% of the thermal rating. 2.2

33/11 kV Transformers

In the case of sub-station having two transformers, each transformer should have sufficient cyclic loading capacity to supply the entire sub-station maximum demand taking into account the short time over loading capacity prescribed in the IS. Alternatively sufficient interconnected feeder capacity at 11 kV between 33/11 kV adjacent substations is provided to meet the affected loads in the event of outage of one transformer. For sub-stations with single transformer sufficient interconnected feeder capacity on 11 kV between 33/11 kV substations is mandatory to enable the maximum demand of the substation to be met in case of failure of single transformer. Modern trend is however to provide minimum two transformers as getting supply at 11 kV bus bar from adjacent substation may not be always practicable. 2.3

Distribution Substations

The economic loading of new transformers lies between 60 to 70 percent of the transformer rating. Action for replacement of the transformer by one of a higher rating should be taken when the maximum load exceeds 70 percent of the transformer rating. Alternatively, additional substation at a suitable location in the near by vicinity should be taken whichever is found more economical taking into account the cost of the losses.

165

3.0

Case Study :

POWERGRID has carried out detailed planning studies for Rural Electrification of Muzaffarpur and Vaishali districts of Bihar. The salient points are discussed below: Vaishali and Muzaffarpur districts have 25 blocks ( Vaishali having 11 Blocks and Muzaffarpur having 14 blocks) and a total number of 3413 villages. For complete electrification of these districts, 2378 villages in above two districts need to be electrified. Summary of Villages and the consumers is given below Particulars No. of Villages Agr. consumers Ind. consumers Domes/Comml consumers Weaker section

Electrification Vaish Muzff Total 450 465 915 996 911 1907 62 255 317 8428 10450 1887 223

275

498

Re-habilitation Vaish Muzff Total 264 246 510 686 681 1367 38 1130 1968 88809 10606 19415 248

267

515

Supply extension Vaish Muzff Total 523 430 953 750 383 1133 153 61 214 12131 10395 2252 243

228

471

G. Total 2378 4407 699 660819 1484

The total load of the above consumers is 71 MVA. The planning of electrification work of above 2378 villages of Vaishali and Muzzaffurpur districts is described below : 3.1

33/11 kV substation

In order to cater the electrification requirement of 2378 villages, first and foremost criterion was to assess the adequacy of existing primary distribution system i.e. 33/11kV substation and out going lines. The study of existing primary distribution network was carried out. Existing primary distribution system in two districts consisted of 24 numbers of 33/11 kV substation mainly located close to urban areas. These substations are already at their optimum loading and are located far off from the villages. Based on the study of existing system the following strengthening of the system was considered necessary: ·

Construction of 10 numbers of new and augmentation of 4 numbers of 33/11 kV sub stations thereby adding transformation capacity by 73.5 MVA

·

Total connected load is 71 MVA and the criterion discussed at 2.2 above is not directly satisfied. However, considering the fact that rural load is generally supplied by rotation for 8 to 12 hours a day by rotation, there is adequate redundandancy built in 33/11 kV Substation capacity.

3.2

33 kV Lines:

Considering the reliability and economics involved in above discussed three options (radial, ring and mesh system) ring system has been planned for 33 kV lines. Thus total requirement of 33 kV line for making ring system has been worked out to be 200 km. 3.2

11 kV and LT system 11 kV and LT system are planned in radial system. Following aspects were considered in selecting of technology and design of distribution system for rural electrification:

166

1. 2. 3. 4. 5. 6.

Technical Loss reduction Commercial Loss reduction Voltage profile Life of distribution transformer Energy auditing Reliability

The consideration of above factors led to the conclusion of High Voltage Distribution system (HVDS). In the proposed system, LT line shall be used to bare minimum and small distribution transformers shall be installed dedicated to a group of houses. The detailed analysis of above aspects is given below: 1.

Technical Loss reduction: Typically 63 KVA transformers along with LT lines are provided for rural electrification in Bihar. Under HVDS system small single phase distribution transformers along with 11 KV lines are planned to be installed dedicated to a group of dwelling units. Therefore the analysis has been done for loss occurring in conventional distribution system with one 63 KVA transformer and 4 Nos. 16 KVA transformers in case of HVDS. Line length has been assumed as 1 Km. 11 kV for HVDS system and 1 Km. LT line in conventional distribution system.

Thus Cost Comparison of 3 phase 4 wire Low Voltage distribution system with 11 kV High voltage distribution system considering energy cost @ Rs 3.5/kWH over a period of 25 years is summarized below: S. System No. Voltage

1 2

0.415 11

Cost of of implementation (Lacs Rs.) 1.37+.48=1.85 1.50+1.2=2.70

Increase in cost (Rs.)

Total Annual Losses

Reduction in Annual Losses

Annual Cost Saving by decrease in

Present Worth of Saving

Net Benefit In HVDS

(kWh)

Losses (Rs.)

(Rs.)

System (Rs.)

85000

(kWh) 100017 3136.6

96880

339082

4899735

4814735

Therefore, considering the incremental cost incurred in construction of HVDS system and saving savings on account of reduced losses, the net benefit in electrification of one village by HVDS in comparison to LT system is to the tune of Rs. 48.1 lacks. 2.

Commercial Loss reduction: In order to reduce the theft of electricity by hooking on distribution system, 11 KV distribution system was selected. It will not be possible to directly hook on 11 kV lines. Further aerially bunched conductors shall be used on low voltage line, to avoid theft.

3.

Voltage profile: The installation of distribution transformer near to the load center will reduce the length of low voltage line and hence the impedance of wire and line drop in voltage. This will improve the line voltage at the consumer end.

4.

Life of distribution transformer: Repeated blows on 3- phase 4wire distribution lines due to imbalance caused by temporary faults such as leakage through branches of trees touching to the lines and short circuit to flow of currents in the transformer, damage the transformers. In case of reduction of LT lines and installations of single phase transformer the damage to distribution transformer will be reduced and regular supply to consumer can be maintained. Taps are the weakest part in a transformer which is not needed in HVDS system. Therefore the transformer life will be more in case of HVDS system.

167

5.

Energy Auditing: Energy metering is planned at 11 kV feeder and sub-feeder for proper energy auditing.

6.

Reliability: Due to the nature of load distribution over a vide area, the total length of feeder and sub meter is large. In order to minimize the outage to consumer in case of fault/ maintenance in some section of feeder, sectionalizers are planned at 11 kV spur feeders.

Considering above, HVDS system is planned and following quantity of 11 kV and LT lines have been worked out: Particulars

Electrification Vaish

Muzaf

Re-habilitation

Total

Vaish

Supply extension

Muzaf Total

Vaish

G. Total

Muzff Total

1 kVTrunk line

81

112

194

67

80

147

0

0

0

340

11 kV Spur line

674

753

1427

486

443

929

368

401

769

3125

LT ABC

230

246

476

181

164

345

163

153

316

1137

LT Overhead

230

246

476

181

164

345

163

153

316

1137

3.3

Distribution Transformer : Single phase: 16, 25 KVA and three phase: 16, 25, and 40 KVA transformers have been planned to minimize the LT line.

Based on above, the quantity of each type of transformer was estimated based on following criterion: a.

For each industrial connection of 10 HP (7.46kW) and above, one no. 16kVA DT.

b.

For agriculture connections (each 5 HP) up to 3-nos, one no.16kVA DT and for connections up to 5 nos, one no of 25kVA DT is proposed.

c.

For Domestic/Commercial connection (each 1kW), the estimation has been done as underSl. No. 1. 2. 3. 4. 5.

No of Consumers

Capacity of DT (KVA)

Up to 10 nos 11 to 15 nos 16 to 30 nos 31 to 40 nos 41 to 50 nos

1x16 1x25 2x16 1x16+1x25 1x25+1x40

Above analysis resulted in following quantity of DTs Distr. (nos.) - 16 kVA - 25 kVA - 40 kVA

Trf.Electrification Vaish Muzaf Total 1012 1149 2161 87 155 242 25 51 76

Re-habilitation Vaish Muzaf Total 663 606 1269 140 176 316 15 112 127

Supply extension G. Total Vaish Muzff Total 1398 1082 2480 5910 104 50 154 712 1 0 1 204

The total capacity of distribution transformer is 121 MVA against the connected load of 71 MVA. This is in line with the criterion discussed at 2.3 above.

168

3.4

Distribution Substation

Distribution transformers are planned to be pole mounted. Three phase transformers shall have TPMO, DO fuse and Surge arrestor on HT side and MCCB/ Hand guard fuse on LT side. Pole mounted distribution shall be provided to provided service connections. Single phase transformer shall have DO fuse and Surge arrestor on HT side and MCCB/ Hand guard fuse on LT side. Basic schematic diagram of the Distribution substation for various ratings of DTs is given at annexure 1. The 11 kV feeder scheme from a sub station is given at annexure II. 4.

Conclusion

The issues and the process involved in planning of distribution system have been discussed with the case study of planning of the Electrification of Muzaffarpur and Vaishali districts of Bihar. It is seen that detailed planning is needed for distribution planning. In the case study it is also seen that HVDS offers many advantages over LT distribution system, 5.

Acknowledgement

The views expressed in this paper are of the authors only and need not necessarily be the management of POWERGRID. 6.

References :

1. 2. 3.

Distribution system Design and Planning by B. B. Das (Consultant) Feasibility report of rural electrification of Muzaffarpur and Vaishali district. Loss reduction in Indian Rural distribution system By Network Reconfiguration. By S.K. Sharma, P.K. Modi, P.P.Sharma, S.P. Singh Rural Power Distribution-Latest Trends and Practices by Inderjit S Anand.

4.

169

170

SESSION – 6 Distribution System Management • Metering, Billing, Revenue Realisation and Resource Mobilisation • Asset and Inventory Management • Risk and Disaster Management

Chairman : Sh. Arvind Jadhav, Joint Secretary, Ministry of Power, Government of India

Key Note Speakers : i)

Sh. T. S. Sridhar, Chairman, Tamil Nadu State Electricity Board “Metering, Billing, Revenue Realisation and Resource Mobilisation”

ii)

Sh. Rajan, Vice President, SBI CAPS “Asset and Inventory Management”

iii)

Sh. Sanjay Kedia, Vice President, Marsh Crisis Consulting, USA ”Risk and Disaster Management”

iv)

Sh. S. Majumdar, Executive Director, Power Grid Corp India “Limited Planning of Distribution System – A Case Study of Rural Electrification”

v)*

Dr. Ashok Manglick, TRANSGRID, Australia “Ensuring Network Reliability in a Competitive Market Framework : TransGrid’s Approach”

Additional Papers included in Binders : 1.* “Demand Side Management : Need and Solution” by Sh. A. K. Saxena, Dayalbagh Educational Institute, Dr. P. K. Kalra, Indian Institute of Technology, Kanpur, Sh. G. P. Hans, Dayalbagh Educational Institute & Sh. D.K. Chaturvedi, Dayalbagh Educational Institute. 2.* “Impact of Electricity Act 2003 on lignite fired boilers in Neyveli Lignite Corporation” by Sh. R. Nedungkeeran, Deputy Chief Engineer (Operation), Neyveli Lignite Corporation 3.* “Real Time Systems for Distribution Management for Urban Systems” by Sh. Alfred Manohar, ABB 4.* “Brief Overview of Southern California Edison Power System in United States of America” by Sh. Bharat Bhargava, Consulting Engineer, Southern California Edison Co. 5.* “Metering, Billing, Revenue Realisation and Resource Mobilisation” by Sh. R. C. Gupta, Vice President, Desein Private Ltd. 6.* “Online Fault Detection Algorithm for Three Phase Radial Distribution Networks” by Sh. G. Akila & Prof. S. P. Reddy, Head of Dept. (IT), Crescent Engineering College, Chennai

* Papers received by the time of compilation

Ensuring Network Reliability in a Competitive Market Framework : Trans Grid’s Approach

Dr. Ashok Manglick Manager, Project Development TransGrid, Australia Abstract Introduction of a competitive framework in the electricity supply industry as part of structural reform worldwide has seen transmission network businesses separated from vertically integrated utilities and run as independent entities. The competitive market environment in which newly established transmission companies have been operating is an unfamiliar territory suffused with conflicting expectations from governments, regulators and customers. This requires the businesses to be cognizant of the new environment and manage the necessary changes to the organisational culture, structure, business processes and systems. The paper analyses the forces that are shaping the management of transmission businesses in a competitive market environment and seeks to shed some light on the unique issues facing transmission companies in ensuring the reliability of the network. 1.

Introduction

Over the last decades many countries including Australia have reformed their electricity supply Industry (ESI). Almost without exception, the reform has reduced the degree of vertical integration of the electricity supply chain and in many cases generation, transmission, distribution and retail have been fully separated and are being run as commercially independent businesses. This has led to the unbundling of costs embedded in the price of electricity that has been a significant driver to efficiency improvement of all sectors concerned. The next stage of the structural reform is the introduction of competition in the contestable elements of the industry, namely generation and retail. In a wholesale electricity market, generators are dispatched based on their bids after network losses and system security are accounted for. On the retail side of competition, customers are offered choices for their electricity retailers, some of which do not own distribution wires business in their franchised areas. Monopoly elements of the industry, both transmission and distribution networks, are regulated and serve as a platform on which competition can take place. Opinions diverge on the roles of transmission in a competitive market environment. Monopoly was traditionally associated with poor performance and high prices. This negative image still dominates the minds of many regulators and as a result pro-competitive regulation is taking shape in some markets. As markets around the world are maturing and particularly in the aftermath of the California energy crisis and blackouts in the North America east coast, Italy, London and other parts of Europe, it is apparent that the reliability of networks is crucial to security of supply in a market environment. 172

2.

Business Environment

Shaping Forces Various forces are shaping network businesses operating a market environment. Figure 1 illustrates the influence of stakeholders whose expectations can sometimes be conflicting.

Figure 1 : Network Business Environment Shareholders Shareholders of a network company have interests common to those of any other businesses who would expect a profitable business that adequately manages its risks and presents a good outlook for growth. In Australia, government policy objectives in relation to energy transmission operators are reflected in legislative requirements. The State Owned Corporations Act enacted in the State of New South Wales sets out the principal objectives which TransGrid as a transmission company must follow. The Act requires TransGrid, •

to be i. ii. iii.

• • • •

to to to to

a successful business : to operate at least as efficiently as any comparable businesses, to maximise the net worth of the State’s investment, to exhibit a sense of social responsibility

protect the environment exhibit a sense of responsibility towards regional development operate efficient, safe and reliable transmission facilities promote effective access to transmission facilities.

These legislative requirements highlight the expectations from the perspectives of a shareholder as well as the government who is ultimately responsible for keeping the lights on.

173

Regulators An economic regulator regulates access, service standards and prices of transmission businesses. To this end, regulators seek to adopt a balanced approach to regulation. On the one hand, it is necessary to set up a regulatory framework that ensures the business operates efficiently and does not extract excessive profits. On the other hand, incentives have to be built in to the regulation approach so that the business is rewarded with reasonable returns appropriate to its risk profile. Maintaining new network investment is high on any regulators’ agenda. However, in order to prevent network owners from “gold plating” or overbuilding their assets, regulators usually set up a development framework that requires proponents of a project to prove the investment proposed is economically sound. In Australia, the process is governed by a ‘regulatory test’ promulgated by the Australian Competition and Consumer Commission (ACCC), the industry’s regulator and watchdog. The regulatory test compares all network development proposals with alternative options and seeks to maximise the net present value of the market benefit. However, the process has proved complex and cumbersome, and has proved to be implicitly favouring competitive over regulated solutions. Consequently, it is not unusual to take up to three years for an augmentation proposal to just get through the rigorous regulatory approval process.

Market Code Transmission companies are registered in the Australian National Electricity Market as Transmission Network Service Providers (TNSP). The Code defines the roles and responsibilities of a TNSP as well as the processes to be followed in relation to connection and access service provision, network planning and development, and network security obligations. The Code also specifies performance requirements of the network that form part of TransGrid’s service standards. To a great extent, a transmission business revolves around the Code. Hence, code compliance is a paramount task to TNSPs. Moreover, subject to market performance and influenced by stakeholders, the development of the Code is an ongoing process, which necessitates the establishment of a regulatory compliance system.

Customers Unbundling of electricity prices reveals the cost of transmission which is collected from customers for using network services. This results in higher customer expectations on the performance of transmission companies and in particular on reliability and the availability of network services. Customers, in particular generators, are trying to influence TNSP service levels through interactions with regulators, governments as well as transmission companies. They may seek compensation if their energy to market is constrained by transmission networks, which highlights the issue of risk management. Risk management is a new concept to a transmission business which was part of a vertically integrated utility. In a market, outages of transmission lines can have significant impacts on the commercial outcomes of market participants. The business must protect itself from litigation by clearly defining its reliability and availability standards and if necessary have insurance coverage. It is neither cost effective nor realistic to plan the network with varying reliability standards depending the requirements of individual network users. The special needs of some customers in relation to higher reliability and availability can be better addressed in the form of connection agreements, provided that the customers are willing to pay for higher service levels.

174

3.

Uncertainties surrounding the role of networks

The competitive framework for the electricity industry brings uncertainties to the management of a network business. In particular, the uncertainty surrounding the role of networks in a competitive electricity market makes it very difficult to formulate and implement appropriate business strategies. The task is even harder for transmission network business as it is crucial to support the competition as well as in delivering reliable electricity from generators to customers and also ensuring the stability of the interconnected power system as a whole. With an increasingly greater focus on the transmission sector, a number of interest groups have been promoting the extension of competition into the transmission sector. This has been supported by the implicit assumption that competition in all aspects of electricity delivery is a good thing. As a result, arrangements for merchant transmission investment (MNSP or Market Network Service Provider) operating along side the regulated arrangements have been established. To date the merchant transmission regime has not worked at all in Australia. It needs to be recognised that merchant interconnectors are driven by maximising returns to the shareholders rather than public good and in general will not act in the interest of customers per se. It is an obvious fact that merchant interconnectors always seek to maintain price differences in order to generate revenues. Another practical issue is how this regime integrates with the existing regulated regime when both regimes involve investment and operation of parts of an integrated transmission grid. As a result, the key question of the role of transmission within a competitive market is being reexamined at a policy level. The fundamental question is whether transmission should be developed and operated to facilitate competition or whether it should compete in its own right. The importance of a strong transmission network in reducing wholesale price volatility and hence risk is also an important consideration. In a wholesale spot market for energy, spot prices can range widely and dramatically over time. A weak transmission system enhances the scope for regional price differences and price volatility. A strong, effectively regulated, transmission network is the key to ensuring reliability of network and facilitating a truly competitive wholesale electricity market.

4.

Structural Arrangements for a Transmission Business

Restructuring as part of the power sector reform process aims to separate the traditional industry functions into new structural arrangements that promote competition. However, competition must not be achieved at the expense of the coordination necessary to achieve the quality and reliability of supply. Structurally a transmission business operating in a market can undertake the following functions: • • • • •

Asset ownership Transmission planning System operation Network operation Market operation

A number of structural options are available ranging from integrating all functions into one body to splitting these functions amongst different organisations. In the England - Wales market, for example, the National Grid Company carries out all these functions under regulated incentive arrangements aimed at driving the management to combine functions in the most efficient way to deliver transmission capability. 175

In the US, the FERC Standard Market Design proposes a super Market and System Operator called a Regional Transmission Organisation. This operates on a ‘not for profit’ public interest basis and does everything related to transmission service delivery except own and invest in transmission. This model accommodates the multiple transmission owners that exist in the US, including a significant number that are also generation owners. In New Zealand, the market operation function is separated and run by M-co. The transmission company Transpower owns and operates the national grid, and is also responsible for transmission planning and power system security. In Australia, NEMMCO is the market and system operator and coordinates inter-state interconnection planning. Each state has its own transmission company with regulated status. Some states like Victoria and South Australia have privatised their transmission assets. Unlike other states, Victoria has separated its planning function from asset ownership and systems operations. It is argued that economic efficiency can be achieved by removing the incentives of TNSPs to gold-plate and by introducing competition into transmission service delivery. However, this approach raises the issues of risk allocation and accountability because it is difficult to separate operating and planning risks and more importantly the independent planner has no financial backing to accept any accountability for performance. In addition, the competition in asset development leads to fragmentation of transmission assets in terms of asset ownership, which introduces additional complexities to administration and regulation. Hence, integration of planning and ownership is a better option as it aligns planning and investment functional responsibility with the accountability of asset owners for transmission service delivery.

5.

Business processes most affected by market Network Planning

The Code sets out a process for network development which involves technical analysis, economic justifications and public consultations. The whole planning activity has to revolve around the code requirements. As network development has cost implications to market participants, augmentation proposals for projects exceeding a certain size are closely scrutinized. The widely differing commercial goals of market participants are often seeds for disagreements and drawn out litigation. In light of this situation, network companies have had to become mindful of the cost versus reliability equation and also take into account the lead-times of extensive economic justifications and customer consultations, which are often compounded with the time taken for environmental impact assessment. Technically, network planning in a market environment needs to deal with added complexity and uncertainty arising from: -

Generators’ bidding behaviour in a competitive market which is difficult to predict as compared to the centrally coordinated dispatch.

-

Capacity planning being subject to market forces and the development of privately funded generation with associated uncertainty and typically short lead-times.

-

Development of privately owned interconnections with uncertain capacity availability subject to bidding behaviors.

To adequately address these issues, planners are often required to carry out extensive market and power system simulations. 176

Asset Management There has been an increasing focus on asset management due to high expectations on reliability and availability of supply. In the State of New South Wales, the electricity supply regulation requires network operators to develop network management plans and to report annually on the performance of the network. TransGrid has accordingly developed a network management plan that integrates service delivery, planning, capital investment, operations and maintenance, and replacement and disposal strategies. Figure 2 is an example of the general thrust of implementing these initiatives. Benchmarking, both internally and externally, has been widely used to drive continuous improvements in asset management practice. TransGrid is an active member of the International Transmission Operations and Maintenance Study (ITOMS). The study sets benchmarks for worldclass performance which is measured against cost and services levels. Detailed Asset Management Plan

Corporate Policies & Grid Standards

Research and Development Projects

Asset Management Working Groups

Benchmarking

Technology Changes

Safety Standards

Technical Performance Assessment

Environmental Policy

Asset Management Strategies Refurbishment Refurbishment or or Replacement Replacement Strategies Strategies

Quarterly Asset Performance Reviews

Maintenance Policies Equipment Service Performance

Co-ordinate Outage Programme

RESOURCE PLAN

WORKS MANAGEMENT SYSTEM Job Sheets

Outage Requests Job Sheets Test Reports Defect Reports

Work Performed Maintenance Standards

Figure 2 : Trans Grid Asset Management Plan

Regulatory compliance Changes in market code and relevant legislation can have significant impact on a transmission business. This requires the impact to be assessed, communicated to relevant staff and reflected in policies, procedures, processes and work practices of the business. To this end, TransGrid has set up a regulatory compliance management programs aimed at ensuring that TransGrid complies with its obligations set out in the National Electricity Market Law, the National Electricity Market Code, regulations and standards. The compliance programs, encompassing the essential structural, operational and maintenance elements, are auditable and involve the whole organisation.

177

Network pricing A typical regulatory approach to a transmission business is to cap its maximum allowed revenue whose determination involves evaluation of asset base, reasonable rate of return on the asset base, allowance for depreciation, operation & maintenance costs. A regulator also determines a pricing structure based on which the revenue can be allocated to various categories of transmission customers. In return for the regulated revenue, a regulator expects the transmission business to reach certain services standards which mainly involve reliability and availability of supply. Initial revenue determination and reviews periodically taken place are vital to the profitability and growth outlook of a transmission business. The business must present a case that fits with regulatory objectives aiming at achieving a balance between efficiency and reasonable returns. Development of asset databases and benchmarking are some of activities that have to take place. Closely associated with the revenue determination process is the data and invoicing system for connection and use of system charges. The development of this system is an ongoing process, as code changes in relation to network pricing must be reflected to remain code compliant.

6.

Conclusion

The restructuring and introduction of an electricity market requires a network business to be cognizant of the new environment and to establish a profitable business through managing expectations and changing organisational culture, structure, business processes and systems. At the same time, strong and reliable networks are necessary for ensuring a reliable electricity supply, an essential ingredient to all modern economies. Therefore, technical functions in a network business such as planning and asset management should be integrated with the market functions for better alignment of responsibilities and accountabilities, and for achieving better overall technical and commercial performance in a competitive environment.

Acknowledgements Valuable input from Peter Trimmer and Fan Li of TransGrid in preparing this paper is gratefully acknowledged. In addition to extensive personal experience through direct and indirect involvement, the following documents have been referred to in this paper. 1. 2. 3. 4.

Australian National Electricity Code, issued by the National Electricity Code Administrator. Regulatory Arrangements for a National Electricity Market – Issues paper by National Grid Management Council, October 1993. Towards a Truly National and Efficient Energy Market - Energy Market Review, for and on behalf of the Council of Australian Governments, Dec 2002. A large number of papers, and Victorian Supreme Court and National Electricity Tribunal proceedings on the issue of Market Network Service Providers versus regulated Transmission Network Service Providers in the Australian National Electricity Market.

178

Demand Side Management : Need and Solutions A. K. Saxena*

P. K. Kalra** G. P. Hans* D. K. Chaturvedi* *Dayalbagh Educational Institute, Dayalbagh, Agra. **Indian Institute of Technology, Kanpur

Abstract Energy is a vital input to development and depletion of energy resources would result in economic stagnation for any country. Demand Side Management (DSM) is a systematic evaluation of energy utilization by matching the available energy to the desired generation for use in various consumer installations with a view to identifying existing energy conservation opportunities. The goal of demand-side management is to smooth out the daily peaks and valleys in electrical energy demand to make the most efficient use of energy resources. DSM programs aim to achieve three broad objectives Energy conservation, Energy efficiency and Load management. Consumers are not aware of efficient energy management practices and they lack technical expertise to implement measures to utilize available energy efficiently. It is possible to manage one’s electricity consumption through using more efficient energy saving equipment, load shedding and or load scheduling. It is, therefore necessary to educate customer by providing a special information telephone line, printed materials, communications campaigns, internet sites, and so on to save energy. This paper describes the need to implement the demand side management options and the customer education.

Introduction India is dependent upon its energy sources for residential and commercial electricity, industrial power, and transportation fuels. India has its own oil, coal, natural gas and other renewable energy resources including solar energy, wind energy, biomass, small-scale hydroelectricity, geothermal heat, and ocean thermal energy conversion. Restructuring in power industries is done to increase efficiency and cut down the costs. Competitive environment for electricity market has been created and this will affect the structure and ownership of the supply industry. Earlier the utilities were paying more attention towards the reforms in the area of power generation and transmission. The electrical power distribution system is geographically very widely distributed is now opened for private participation and this will encourage competition. Rapid growth in demand for electricity is expected throughout the world. We therefore need efficient systems to ensure a good power quality and continuity of supply. Increasing number of non-linear and electronically switched loads operated by industrial, commercial and residential customers has led to higher incidences of harmonic distortion of the voltage and current waveforms thus affecting the power quality. The security and economy of operations are the other aspects. Demand Side Management is a systematic evaluation of energy utilization by matching the available energy to the desired production for use with a view to identifying existing energy conservation opportunities. The goal of demand-side management is to smooth out the daily peaks and valleys in electric energy demand to make the most efficient use of energy resources and to defer the need to develop new power plants. This may entail shifting energy use to off-peak hours, reducing energy during off-peak hours. Lack of consumer awareness and technical expertise on opportunities to install efficient technologies or adopt efficient management practices and short-sightedness on investment decisions are the causes for waste of energy. The customer has neither the time nor the knowledge to respond to 179

cost saving and environmental benefits associated with each of these utilities separately. Training programs needs to be launched for the consumers to make them aware of the DSM need and benefits and educate them in general to the value of electricity and energy conservation methods.

Demand Side Management and its implementation DSM strategies includes peak clipping, which seeks to reduce energy consumption at the time of the daily peak by controlling use of heavy load appliances, valley filling to make the load curve smooth by shifting the load say charging electric vehicles at night, load shifting, and conservation, which involves reducing the entire energy load. All DSM strategies have the goal of maximizing efficiency to avoid or postpone the construction of new generating plants. In contrast to “supplyside” strategies, which increase energy supplies, DSM strives to get the most out of its existing energy resources. DSM involves consumers’ changing their energy use habits and using energyefficient appliances, equipment, and buildings. Real time and/or time-of-use metering, controlled usage through tripping devices, interruptible rates, and many other measures may be used to fulfill the above goals..

International Status in DSM The developed, developing and industrialized countries have been showing greater interests to DSM applications and are achieving greater benefits from the implementation of DSM. United States, Japan, Canada, Germany, France, Italy and China have developed number of incentives, laws, regulations and policies for successful implementation of DSM projects. Energy efficient lighting (CFL) initiative was launched in 1999 in Argentina, Czech Republic, Hungary, Latvia, Peru Philippines and South Africa. Norway - has established an organization, ENOVA, to coordinate all energy efficiency activities. Distribution companies in Peru after deregulation of their power industry have taken initiative to understand their customer’s problems and improve their energy utilization. Philippines - Is still in the process of deregulation/restructuring, issued a government directive to implement DSM programs. Singapore has given tax incentive to launch DSM objectives. South Korea - Which is dependent on fossil fuel and nuclear power for their electricity generation is encouraging DSM activities by providing rebates, price reduction and compensation for lost revenues in DSM implementation. They have launched load management programs by peak shifting, peak shaving and innovative tariff systems. Spain is also in the process of restructuring and they have introduced DSM in their electricity Act to control residential lighting and appliances and industrial motors and reactive control. Sri Lanka - Has designed a Code of Practice for Energy Efficient systems. Sweden where environmental issues are becoming increasingly important is working to improve its energy efficiency by increase in its use of renewable energy. There utilities are investing their own funds to attract customers. Taiwan and Thailand - Are also giving financial incentive for DSM programs thereby saving energy and harmful emissions. They are using efficient lighting and air conditioners to reduce energy loss. United Kingdom - Restructured their electricity industry in 1992 launched DSM programs to eliminate toxic emissions. Vietnam launched DSM program in 1999 and launched time-of-use meters and asking the consumers for voluntary load control. In Agra in a particular residential society energy conservation is implemented by discouraging its customers to consume more and heavy penalties are imposed in different slabs of consumptions.

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Customer training Importance of training in the current context is not recognized. The scheduling and management of training has not been on the top priority list of activities in Indian Power System Operators. For ensuring an efficient utilization of the power at the customer end, we must emphasize and plan to educate the customers. The customer education must deal with elimination of waste in energy consumption. Customers are made aware of the existing energy saving opportunities in their premises and are brought in contact with manufacturers of energy saving equipment. Electricity consumption habits of Indian consumers are seriously deficient. They are normally not aware of the qualities of the products available in the market. They do not know what will be the optimum requirement for their need and how and where to install a particular electrical gadget. The bottleneck is that customers are not investing in energy efficiency because the cash resources of most of the residential customers are limited and energy efficiency demands some investments. Most consumers are unaware of the benefits of energy efficiency improvements. They fail to make better use of awareness if any and are susceptible to the enticement of false advertisement. An unwise decision by the customer to use electrical power without optimizing its will burden them. It is the business of education to correct and train them. They are not expected to shut off their load to save money but we can train them the means for energy conservation. For customer training we must first classify the customers in various user categories. This classification can be on the basis of income group, profession, consumer category or educational qualifications. A further sub-classification can be done on the basis of the type of the electrical gadgets they use in their day to day life. Before designing a training curriculumwe must analyze the need for training, what should be Taught, Who shall teach, where the training should be conducted, How to teach and How to evaluate? The detailed training program includes : Design training curriculum: The most important aspect of training curriculum is to integrate theory and application in the training cycle. Document accession and review: Review of existing training programs, if any, used for training. This includes criteria used for training, procedures used to maintain and manage the progress and the responsibility for managing training. Task Analysis: Analyze the performance and interview them about performance. Enquire about the frequency of the task performed and difficulties to learn, amount and type of supervision available. Validate the task performed with the qualified persons to check for its completeness and accuracy. Selection of tasks for training: Classify the task to be performed on priority basis and arrange for the review and approval of the task performed. Detailed task analysis: After selecting the task to be trained analyze the requirements for performing each task. This requires decision making, knowledge recall and manipulations of some functions. Check for the estimates of difficulties, frequency of performance and importance of each task. Interact with experts and planners. Solve any problem that exists. Behavior and objective specification: Define what a trainee was expected to be able to do, under what conditions it must be done and what is the level of proficiency. Method/media selection: Select type of leaning required, method required and practicability of the program. Methods may include training in energy awareness, survey visits, energy advise visit by advisors to consumers and provide them information, literature and advice on the use of electricity. Launch information programs on technologies and management with a special information telephone line, printed materials, communications campaigns, internet sites, and so on. Free energy audits to identify DSM opportunity, rebates or subsidies to support DSM improvements must be arranged. Information on customer bills that illustrates energy consumption and the average energy consumption among all consumers be provided.

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Performance appraisal and evaluation of the training : Once the training is over individuals performance may be checked by holding question/answer sessions and holding tests. One important way to reduce the cost of generation is to reduce energy consumption. Instead of building new power plants to respond to increasing customer demand, electricity producers can try to reduce their customers’ demand for power by offering special programs for customers of various categories to achieve energy conservation, energy efficiency and load management. Industries must mobilize their resources for meaningful dissemination of technical knowledge on new technologies. They must also identify and evaluate different choices of technologies available today and create quality consciousness and technology up-gradation amongst indigenous manufacturers of various energy efficient systems. In this paper we present the performance of various electrical gadgets and we can convince the customer about the selection of particular item not only on the basis of cost but also the quality and performance. The net saving in the normal life span of the equipment can also be predicted on the basis of results obtained. Tubular Fluorescent lights and Compact Fluorescent Lamps (CFL) We are using 17-20% of power generated for lighting compared to developed countries average of 8-9%. Average light levels in major installations even at this high usage are 40 to 50% lower than those of developed countries who are reaping the benefits of advanced technologies and best maintenance practices. This shows the scope for energy conservation using efficient lighting technologies as saving power has a direct impact on our environment. It is proven that saving 1 unit of electricity at point of use saves 2 units at point of generation. There are various kinds of lighting appliances. High efficiency (light quantity per unit of electric power) lamps such as tubular fluorescent lamps and compact fluorescent lamp can be used as compared to incandescent lamps. Energy efficient slim tube lights not only use minimum of our natural resources but coupled with high efficiency electronics ballasts offer best choice for energy efficient indoor lighting. Lighting must be appropriate to each appliance and calculated intensity of illumination. Illumination drops upto 30 % in six months depending upon the degree of contamination of a lamp or its cover. Removal of cover improves the illumination by approximate 25 %. Instead of waiting for lamps to fail, lamps should be periodically replaced according to manufacturer’s data as lumen descent after claimed lamp life. Cost of lighting equipment is composed of initial cost, running cost and maintenance costs. Buildings, laboratories and class rooms must be so designed that during the day time maximum utilization of natural light is possible. Table-1 shows the characteristics of different CFL’s. Table-1 (Performance of 15 Watt CFL) Voltage (Volts) 150 160 170 180 190 200 210 220 230 240 250

Current (Amps) 0.01 0.01 0.01 0.015 0.015 0.018 0.02 0.04 0.05 0.05 0.05

A Power (Watts) 8 8 8 8 8 8.5 8.5 9 10 12 12

LUX 86 94 102 108 116 123 129 135 140 147 152

Current (Amps) 0.1 0.1 0.11 0.11 0.11 0.11 0.11 0.11 0.11 0.12 0.12 182

B Power (Watts) 8 8.25 9 9 11 12 12 13 14 15 16

LUX 168 193 211 229 244 259 274 288 305 317 330

Current (Amps) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

C Power (Watts) 8 8 9 9 9 9 11 12 12 13 14

LUX 153 173 188 204 220 233 249 262 275 287 300

Incandescent Lamp A 60 watt and 100 watt incandescent lamps are normally used for domestic lighting. They are available with different brand names and prices. The customer must be trained to select suitable quality of bulb. Performance of various brand lamp of 100 Watt is shown in Table-2 and the effectiveness of the individual can be interpreted from it. The lux generated by individual reflects the quality with regards to the cost. Table-2 (Performance of Incandescent Lamp) Voltage (Volts) 150 160 170 180 190 200 210 220 230 240 250

A @ Rs.9/Current (Amps) 0.35 0.36 0.37 0.39 0.40 0.41 0.42 0.43 0.44 0.46 0.47

B @ Rs.9/-

Power (Watts) 47 60 64 72 80 85 92 97 104 109 117

LUX 299 362 433 542 650 762 890 1044 1195 1358 1537

Current (Amps) 0.32 0.33 0.35 0.36 0.37 0.38 0.39 0.40 0.41 0.42 0.43

Power (Watts) 50 56 60 67 72 80 84 92 96 102 108

C @ Rs.5/LUX 209 265 330 402 480 580 690 789 890 1050 1202

Current (Amps) 0.30 0.32 0.325 0.33 0.34 0.35 0.36 0.37 0.38 0.39 0.40

Power (Watts) 43 52 56 61 68 73 80 85 89 96 102

LUX 178 215 268 327 404 475 566 668 750 862 977

Stabilizers Stabilizers are required in most of the household because the distribution companies do not maintain the proper voltage level. The variation in voltage level is ranging from 140 to 250 volts. This necessitates the use of stabilisers either at the mains or individually for the refrigerators, TV and other gadgets. The main component of the stabilizers is the step up/step down transformer. Although the transformer is treated to be an efficient device but the efficiency decreases as the quality of wires and the core material varies. Since these stabilizers are always connected to the mains, the losses are continuous in nature. Table-3 shows a comparison of power consumed by the stabilizer of 1 KVA. Table-3 (Performance of 1 KVA stabilizer) Voltage (Volts)

150 160 170 180 190 200 210 220 230 240 250

No Load A Current (Amps) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

On 100 Watt Lamp Load A B

B Power (Watts) 8 8 8 8.5 8.5 10 10 10 10 10 10.5

Current (Amps) 0.04 0.06 0.06 0.1 0.11 0.12 0.08 0.09 0.09 0.1 0.11

Power (Watts) 8 8.5 8.5 12 12.5 14 12 12 12.5 14 16

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Current (Amps) 0.64 0.65 0.54 0.56 0.58 0.46 0.47 0.52 0.54 0.44 0.45

Power (Watts) 98 104 96 100 110 96 100 108 114 98 104

Current (Amps) 0.64 0.66 0.55 0.58 0.6 0.48 0.49 0.51 0.52 0.44 0.45

Power (Watts) 98 106 96 104 112 96 102 110 118 102 108

Inverters and UPS A survey was conducted on a residential locality comprising of about 1000 houses and it was found that the more than 70 % of customers are using inverters of 500 VA ratings a good numbers are using UPS for there personal computers. The inverter consumes a noticeable amount of power during charging and causes continuous power loss due to transformers installed in it. They are also a major source of generation of harmonics on the system and degrade the quality of power supply. Table-4 shows the performance of different brands of inverters and Table-5 shows the performance of UPS. Table-4 (Performance of Inverters) Voltage (Volts)

At No Load

Load (100 Watts)

Current A

(Amps) B

Power A

(Watts) B

Current A

(Amps) B

Power A

(Watts) B

150 160

0.4 0.6

0.55 0.62

40 68

50 54

0.92 1.13

0.80 0.88

30 45

104 112

170 180

0.8 0.85

0.68 0.71

104 108

56 59

1.38 1.43

0.91 0.97

112 124

120 128

190 200

0.92 0.98

0.74 0.78

116 120

60 60

1.50 1.54

0.99 1.0

144 160

134 140

210 220

1.01 1.06

0.79 0.80

122 126

62 62

1.58 1.6

1.02 1.03

172 192

148 156

230 240

1.08 1.1

0.80 0.80

128 132

64 64

1.63 1.65

1.04 1.04

204 220

162 170

250

1.14

0.80

130

64

1.66

1.05

232

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Table-5 (Performance of UPS) Voltage

At No Load

On Load of 100 Watts

(Volts) Current (Amps.)

Power (watts)

Current (Amps.)

Power (watts)

150 160

0.25 0.36

10 10

0.75 0.81

104 114

170 180

0.48 0.24

10 10

0.89 0.66

126 108

190 200

0.31 0.41

10 10

0.70 0.76

116 124

210 220

0.20 0.21

9 9

0.58 0.61

106 116

230

0.30

10

0.65

124

Ceiling Fans Ceiling fans are available in different sizes and different power ratings. Normally 1200 mm and 1400 mm size of fans are available. The customers are not able to decide that for their room size which fan will provide better air. These fans consume different power depending on their size. The air delivery depends on the angle of blades and angle of blades affects the power consumptions also. So customer needs training to select proper size and proper quality fans. Table-6 shows the W = average power consumption (watt), AD = air delivery (cubic meter per minute) and COS = price (Rs.) of some of the samples. 184

We have recently converted the old ceiling fans of shaded pole (SP) type into capacitor run type and reduced its wattage from 120 Watt to 60 Watt only. Table-6 (Performance of Ceiling Fans) Size

A

B

C

D(SP)

E

1200mm

W/AD/COS 78/230/800

W/AD/COS 65/220/765

W/AD/COS 52/210/686

W/AD/COS 98/280/300

W/AD/COS 75/220/1250

1400mm

85/270/900

61/280/865

63/271/768

120/330/500

90/273/1400

Water Pumps The water level is going deeper day by day and the municipal corporations are not supplying the desired quantity of water. Residents have to make their own arrangements for water. As the water level is falling, to withdraw water from a deep bore well submersible pumps are most suitable. These pumps normally operate at a lagging power factor (lies 0.62 to 0.72) without any device for power factor improvement. The customers must be trained to install capacitors to relieve the distribution lines by improving power factor. Results Some calculations for the money wasted in unwanted loss in the inferior quality of electrical gadgets are performed and results are given below. For a ceiling fan of higher power rating, if the normal running of fan is 15 hour per day and the difference in power rating is 36 watts. The energy wasted for say 8 months of fan use in a year will be roughly 129 KWH (Rs. 36*15*8*30*3 = 405/- per year). This shows that even if we replace our old fans working on shaded pole principle by a new fan the money invested can be recovered within a year or two. For the voltage stabilizer, the equipment is connected at no load for 24 hours and voltage input is 200 volt the total power loss in a day is 456 watt (or 167 KWH of energy per year i.e. a loss of Rs.525/- (approx) per customer). This amount reaches to crores of rupees if total number of stabilizers used in the country is taken into account. This loss will change further if we take into account the transformation loss at full load. The figure only refers to a 1 KVA stabilizer but in actual practice the stabilizers having range from 0.25 KVA to 5 KVA are used more frequently. So if the power quality is maintained by the utilities this revenue loss and energy loss can be eliminated. The electromagnetic radiations produced by some of the energy conservation devices have not been studied so far. These electromagnetic radiations affect the health of the user. We must provide some shielding and properly place such equipment so that effects of is eliminated. We are doing research in this area and will soon come up with some fruitful results. Conclusions Demand side management is an important tool to balance the supply and demand situations. Implementation of DSM will be beneficial to the nation, the utilities, users and all participants. This may reduce environmental pollution, energy bills, reduce cost of power generation, improve load management, increases safety of grid and improve economic development. Technical (energy efficient systems), Financial (low interest, rebate, tax concession, special benefits), Pricing (special pricing mechanism), Knowledge (guiding customers for efficient use of electricity by publicity, consultancy, seminars, exhibitions) and administrations means (laws, regulations policies) are the important measures of DSM. Government/ utilities must provide sufficient incentives for the implementations of DSM options to the customers. 185

Training programs must be launched for the consumers to make them aware of the DSM need and benefits and educate them in general to the value of electricity. Real time metering, time-of- use metering and controlled usage through tripping devices may be helpful in DSM. Participation of utilities can be useful in facilitating consumer education. Slow decision making process, political influence and uncertainties must be eliminated for better energy conservation. The customers must be encouraged to use energy saving and energy efficient equipments on the other hand the regularity commissions must ensure that the electricity tariff should not have a minimum unit charge to ensure energy conservation. The government must also ensure that the electrical gadgets available in the market are of proper quality. Further if we maintain our distribution system and maintain the voltage level to acceptable limits by installing suitable voltage compensators and maintain the continuity of supply the overall power crisis can be eliminated and the need for voltage stabilizers and U.P.S. is eliminated. Voluntary load reduction program may be launched and the consumer and distribution utility must share the savings in the load during high load period. Scarce capital resources thus can be freed for other purposes due to more efficient use of existing power generation capacity, less environmental pollution and decreased energy intensity of Indian industry. The per capita availability of power increases due to its more efficient use by each household using energy saving technologies. A more productive work environment will be created with energy efficient technologies as avoidable wastage is taken care of.

References 1. 2. 3. 4. 5. 6.

Bureau of Energy Efficiency-India Action Plan: Thrust Area : Demand Side Management, http: /www.bee-india.com/about bee/action plan/06 ta2.htm (BEE-India 2003) Carter, S. “ Breaking the consumption habit: rate making for efficient resource decisions” The Electricity Journal, December 2001. Cavanagh, R. and Sonstelie, R. “ Energy Distribution Monopolies: A vision for the next century” Electricity Journal, Aug/sept. 1998 “Demand Side Management in China” A report by Natural Resources Defense Council, pp. 1-85, October 2003. Goldstein, D. and Geller, H., “Equipment efficiency standards: Mitigating the global climate change at a profit”, Physics and Society, Vol. 28(2), April 1999 Hagler Bailly,” Promoting energy efficiency reforming electricity markets: A guidebook for stakeholder, A report for the office of energy, environment and technology, US agency for International Development, Report No. 98-04, March 1998.

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Impact of Electricity Act 2003 on lignite fired boilers in Neyveli Lignite Corporation by R. NEDUNGKEERAN Deputy Chief Engineer, Neyveli Thermal Station - II

Abstract To maintain socio – economic sustainable development, it is necessary to secure reliable supply of electricity and energy to the different sectors of the economy. While developed countries have the facilities to reach this target, developing countries like ours face many difficulties in meeting their electrical energy demand. The expected economic development will considerably boost energy consumption and more particularly demand for electricity, requiring new generating capacities and infrastructures to be added. India has an installed capacity of about 1,07,972.80 MW at end March 2003. The ministry of power envisages ‘Power for all’ by 2012, which includes electrification of all villages by 2007 and full coverage of households by 2012, which aims to more than double existing power generation by a considerable 100,000 MW by 2012. This target is seen as vital in sustaining the country’s economic growth. The newly legislated electricity Act 2003 will result in substantial opening in the energy market for power generation equipments, transmission and distribution systems upgrades, expansion and operations and maintenance (o & m). Energy companies that can supply all of these energy needs are therefore ideally placed and can make a real impact on meeting the 2012 target. Through this paper much emphasis is stressed on the salient features of electricity act and its varying impact on central power generating company like Neyveli Lignite Corporation (Ministry of coal-GOI), which utilizes lignite which is an inferior form of coal with low calorific value, high moisture content and low ash content.

1.0

Salient features of electricity Act 2003

-

The Central Government from time to time prepare the National Electricity policy including the tariff policy in consultation with the State Govt. and the authority for development of power systems.

-

Obligation to supply electricity to rural areas

-

Any generating company may establish, operate and maintain a generating station without obtaining a license.

-

A person may construct, maintain or operate a captive generating plant.

-

License can be granted by the appropriate commission to transmit, distribute and undertake trading in electricity in any area.

-

Metering of all electricity supplied made mandatory.

-

The Central Government may establish at the national level a National Load despatch center for optimum scheduling end despatch of electricity among Regional Local despatch center.

-

The appropriate commission shall, subject to the provisions of this Act specify the terms and conditions for the determination of tariff.

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-

Constitution of central Electricity commission.

-

Establishment of state commission by the State Govt. concerned.

-

Establishment of an Appellate tribunal by Central Govt. to hear appeals.

-

Aggrieved by any decision or order of the appellate tribunal , provisions given to the person to file an appeal in the supreme court.

2.0

Impact of electricity act on lignite boilers

(A)

According to electricity act 2003, the Central government from time to time prepare and publish the National electricity policy and tariff policy. These policies will be the guiding factor for Regulatory commission to define the tariff rate and other rules.

Tariff fixation is an essential ingredient for any power generating station, while bringing about any new system of operation. If the present level revenue of generators is not protected, this may lead to lower revenue realization and the government owned generating station may slip into a sick state. The revenue earned by the govt. companies is only ploughed back for augmenting further generation capacities by way of expansion / life extension of existing power stations. Availability based tariff is proposed for implementation for the first time in the country. There is no prior experience with this type of tariff, which also has a new element of tariff, the payment for which is linked with frequency. In view of the following difficulties encountered by lignite boilers of NLC constant load is not possible due to (a)

Characteristics of lignite vary very widely, with the calorific value of lignite at entry to pulverized fuel burners varying from 1900 to 2500 kcal/kg.

(b)

Contamination to an extent of 5% of included sand, clay etc.

(c)

Presence of marcarite ( Iron sulphide ) which is root cause for slagging.

(d)

Moisture content in lignite being high (50%), the quantity of lignite being handled is of the order of 35,000 to 38,000 t/day. During rainy days the lignite becomes slushy. These pose constraints in maintaining the generations.

(e)

The fuel supply (lignite) is from a single source only and hence the fuel as mined has to be fired in the boilers. Apart lignite cannot be stored for long durations, variations in the quality of lignite severely affects the performance of the units.

(f)

The lignite mine being open cast, gets flooded during rainy seasons severely affecting lignite excavation.

(g)

Frequent change over of pulverizing mills is necessary in view of the problem faced in the milling system due to quality of lignite.

(h)

Construction of boilers at neyveli power station is of unique tower type design (82 M height) which makes water walls vulnerable for tube puncture and the bottom ash handling equipment susceptible for damages with slag/clinker falling from heights.

The above said are risk factors faced by Neyveli boilers and is to be considered to determination of tariff and norms.

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(B)

According to electricity Act 2003, any generating company may establish, operate and maintain a generating station without a licence under this act, if it complies with the technical standards relating to grid. India’s power sector has a long history of failing to meet expectations. Despite several initiatives since 1991 the actual capacity addition in the power sector has fallen short of targets by nearly 50% in both eighth and ninth five year plans. Our country attempted to speed up the rate of new capacity additions by opening the sector up to private participation in 1991, making a series of major changes in order to attract private investment. Private developers was given tax benefits, guaranteed a 16% return on equity and given foreign exchange protection on equity return. Yet the results of the independent power producer (IPP) initiative have been disappointing. According to govt. figures, an additional 100000 MW is required between 2003 and 2012. In the 10th Five-year plan, our country aims to add 46,000MW. Even the lower target of 36,000MW seem unlikely when considering that the best ever achieved was 24,000MW in the 1982 planning period. Full capacity utilization of a power station for all the time of the year is found not feasible and with the addition of capacity as foreseen above , this becomes far from reality. Thus this becomes an important consideration for the determination of the sustainability of the generation.

(C)

According to electricity Act 2003, it provides for open access to transmission system from the date of the enactment of the act and open access to distribution system as per the terms and conditions and time frames stipulated by the state commissions. Neyveli Lignite Corporation (NLC) under the administrative control of Department of coal under the ministry of mines, is an integrated mining cum power house complex. The existing Mines I and II feed the thermal power stations I and II respectively. While the thermal power station – I of capacity 600MW feed its power entirely to the Tamilnadu Electricity Board, the power generated from Thermal power station –II consisting of two stages, stage – I of 630MW (3x210MW) and stage 11 of 840MW (4x210MW) is shared by the southern Electricity Boards viz, TNEB, KSEB, KPTCL, APTRANSCO & Pondy Electricity dept in the ratio as allocated by CEA from time to time. Generating companies should be given some authority at least for 15% unallocated power so that this can be utilized for the purpose of direct power supply, trading of power supply to better paying customers. Such provisions are necessary to stimulate the conditions for development of power market and to promote competition and efficiency in the central owned power generating units .

(D)

According to electricity Act 2003, it provides encouragement of competition, efficiency, good performance etc., and safeguarding of the consumers interest and at the same time, recovery of the cost of electricity in a rewardable manner. It is only through various elements of electricity tariff, which are allowed to the utilities to be recovered from their customers will enable them to recycle the resource. These tariffs coupled with incentive for generating surplus with best practices followed by the utilities with respect to operational and financial management could help to mobilize internal resources to be ploughed back in power sector. Increase in target availability for recovery of full fixed costs to 72% compared to 68.49%, which has increased the risk of non- recovery of fixed charges. In the event of long forced outages of boilers financial performance of the station are severely affected. While fixing tariff factors like UI energy factor, Free governor mode, captive generation, influence of reforms of state electricity boards is to be taken into consideration.

Conclusion The Electricity act 2003 will open up India’s energy market and help meet its target of doubling output by 2012. I t provides avenues to approach the customers by the utilities who would compete based on value of their services and total commitments to customers. Customer –focussed environment is fastly emerging amongst the utilities. It is high time to focus our attention that for central power generationg units like NLC, revenue generated from the energy sales is the only 189

source of income to repay loan, taxes, duties. That is why, for the sales of energy to the buyers the tariff on power should be given prime importance considering all factor listed in this paper. Financing is one of the main constraints for the development of the energy sector. Large capital investment are required to add new generation capacity with the growing demand on public budget and the reluctance of governments to make adequate investments in the provision of energy, govt. owned power companies depend on their own with the implementation of electricity act 2003. It is of the general view that all power players in the field of power generation be treated alike and given equal chances.

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Realtime Distribution Management for Urban Systems Alfred Manohar Asst. Vice President, Network Management – Utility Automation ABB Limited, Bangalore Abstract The Power Industry is in the midst of a transformation process – from being Energy suppliers to becoming Energy Service Companies. Everyday the Distribution Utilities face new challenges and have to improve productivity and reduce operating costs and maintenance costs whilst providing customers with a reliable power supply and a broad range of services. To achieve rapid success the effective use of Information Technology is essential. The demand-supply gap in power in India is expected to grow by at least twenty per cent this year. The trend is expected to continue in the near future, with no significant generating capacity coming up in the country, may give rise to a power crisis. It is thus imperative that power utilities look at increasing efficiencies in distribution networks, which have among the highest transmission and distribution losses in the world at close to and upwards of 30 per cent. In addition, the social pricing for rural and other sectors puts an increasing pressure on utilities to improve productivity as also reduce operating and maintenance costs to remain financially viable. With the advances in telecom & IT, the new millennium has leapfrogged into a revolution in networking and communication technologies to offer automation as a solution to improve distribution efficiencies. Distribution Management System is a tool for enterprise-wide management of an electric utility system. In other words, an ERP for an electric utility that, properly applied, provides for efficient operations, enhances operational outputs and translates into economic benefits. Some of the initiatives in distribution management include complete distribution automation, city power distribution automation, electric SCADA and distribution management with automatic meter reading for electric utilities. Need to automate Existing distribution systems have certain inherent inefficiencies due to their legacy. For one, most systems are monitored manually. This results in maintenance taking place only during breakdowns. The present system also does not ensure reliable and complete power system and usage information that can facilitate trend forecasting or help the utility in better analysis and planning. New challenges are faced , as imposed by the deregulation of the energy markets, greater environmental concern and the proliferation of open information systems. The new energy context requires revised strategies to confirm one’s position as a prime power utility. SCADA systems Internationally, power generation, and power transmission and distribution attract equal investments. In India too, in the last couple of years, utilities have started investing increasingly in various distribution automation tools for both cost reduction and service benefits. One major tool available for power utilities is the Supervisory Control And Data Acquisition (SCADA) system. SCADA refers to a system that enables an electric utility to remotely monitor, coordinate, control and operate distribution components, equipment and devices in a real-time mode from remote locations with acquisition of data for analysis, and planning from one central location.

191

Today, no utility can afford not to have a suitable SCADA system to monitor and control its distribution network. Distribution automation through SCADA systems directly leads to increased reliability of power for the consumers and lower operating costs for the utility. It results in forecasting accurate demand and supply management; faster restoration of power in case of a downturn and a quick, alternate arrangement for power for important/emergency locations.

Enterprise wide Integration of SCADA & DMS

Automation for both and cost and service benefits These benefits accumulate in areas related to investments, interruptions, and customer service as well as in areas related to investments, interruptions, and customer service as well as in areas related to operational savings. 192

Economic benefits Investment related benefits of Distribution Automation come from a more effective usage of the system. Utilities are able to operate closer to the edge - to the physical limits of their systems. Distribution Automation makes this possible by providing increased availability of better data for planning , engineering and maintenance – these further result into capital deferred benefits. Lower operating costs are another major benefit of Distribution Automation achieved through improved voltage profiles, curtailed VAR flows, repair and maintenance savings, reduced feeder primary and distribution transformer load losses and load management. Improved reliability On the qualitative side, improved reliability adds perceived value to the customers and reduced number of complaints - due to Volt-VAR control, load balancing, Trouble call management, Emergency load shedding features of the state of the art Distribution Automation systems such as ABB’s S.P.I.D.E.R. DMS system. Compatibility Distribution Automation spans many functional and product areas including Computer systems, application software, Remote Terminal Units (RTUs), Communication systems and metering products. ABB’s Electrical engineering expertise built up over one hundred years has enabled us to develop optimized solutions in terms of integrated systems, products and services for Distribution Automation systems.

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Urban Systems SCADA systems have come of age. The advances in communication technology, computer hardware and software – open system architecture, microprocessor based field devices – intelligent electronic devices (Remote Terminal Units) have completely changed the dynamics and utility of present day SCADA system as compared to the systems which were in existence only a few years ago. Today a field data communication device (RTU) can itself log on to the internet, upload the data to the host computer and receive tele-commands through the net. Added to this the open architecture design of the software enabling a host of application packages to be integrated, transforms the SCADA to be a very effective ERP tool for the electric utility A Distribution management system is required for the smooth operation of the network and to cater to the users demand for reliability and performance associated with high-quality, standardized and proven designs. Nevertheless, as each utility operates its network differently, it requires functionalities, features, and control system capabilities often associated with tailor-made designs. An integrated SCADA system for an urban city distribution system comprises of a host of distribution automation features. Focus of Distribution Management First Priority - Control It is apparent from the majority of recent DMS implementation and surveys that been completed that implementation of remote control provides the fastest and greatest benefits to distribution operations. Therefore we will state the first priority of any DMS is real-time system control provided by the SCADA. The depth of this control though is again dependent on economics. The depth of control with the largest payback is at the substation level (SA and traditional control through RTUs) down to the MV feeder circuit level. The next level is extended control or feeder automation (FA) outside the HV/MV substations. The economic penetration of FA is determined by the Automation Intensity Level (AIL), which is defined as the percentage of all switches below the primary substation that will be automated - placed under SCADA control. The AIL produces a certain level of system performance in terms of reduction in average outage duration. The AIL verses network performance level improvement and thus automation expenditure is one of diminishing returns as shown in the figure below for a typical feeder.

194

AIL is a key defining parameter of not only volume and performance improvement, but geographical location of the preferred location for automation. It must be set at the outset of any DMS project including FA. In summary the following levels of Depth of Control can be defined. DOC Level 1 - Sub-transmission down to grid (primary) substations including the medium voltage feeder circuit breakers within the substations DOC Level 2 - Level I Extended to remotely operate (Feeder Automation) switching and volt/var control devices along distribution feeders outside the substation. DOC Level 3 - Including an element of control of low voltage networks. This level has not so far been justified by utilities however those with significant LV networks are viewing such extensions as the next areas for operational improvement. Second Priority – Control Room Management The second priority is to be able to manage the entire MV network of combined remotely controlled switches (10-15% max) and the remaining manually operated devices. This is accomplished by the Control Room Management function, which employs a connectivity model of the entire electrical network, which can be viewed graphically. The diagram can be dressed manually to show changes in manually operated devices, as they are implemented by field crews, the application of tags to show areas of work or restrictions and also temporary network changes. SCADA derived information is displayed in real-time. Unconstrained decision support decision support tools form the core of DMS advanced applications. They are les data dependent of the two categories (unconstrained and constrained) and rely purely on the analysis of network topology to provide operator support for all connectivity based analysis without considering network capacity line and load parameters and operating constraints. Such applications include · · ·

Dynamic Network Colouring Switch Order Planning and Execution Fault Location, Isolation and System Restoration (FLISR)

They provide large incremental benefits without the need to assemble difficult to obtain data on network parameters and loads. Third Priority - Outage Management (Trouble Call Management) Different approaches to Outage Management have been taken in the industry and it is worth discussing these in order to recommend an appropriate solution for the Utility network. Utilities with very limited penetration of real-time control but good customer and network records use a Trouble call approach, whereas those with good real-time systems and extended control were able to use direct measurements from automated devices. The former solution is prevalent in the USA for primary networks (MV- medium voltage) where distribution primary substations are smaller and except for large down town networks the low voltage (secondary) feeder system is limited with on the average between 6 and 10 customers being supplied from one distribution transformer. This system structure makes it easier to establish the customer-network link, a necessity for trouble call management systems if outage management is to yield any realistic results. In contrast European systems with very extensive secondary systems (up to 400 consumers per distribution transformer) concentrated on implementing SCADA control thus any MV fault would be cleared and knowledge of the affected feeder known before any customer calls could be correlated. A trouble call approach to be truly affective would have to operate from the LV system where 195

establishing the customer network link is more challenging. In these cases trouble call response was aimed at maintaining customer relation as a priority over fault location which is achieved through a combination of system monitoring applications (SCADA, FA and FPIs1) and advanced applications. DMSs are now combining the best of these approaches to achieve real-time solutions on the network with customer-oriented feedback. As a result of the two approaches two similar but different architectures have evolved. A.

GIS Centric.

This is based on an extension of the GIS based geographical distribution network connectivity model and has been promoted by suppliers of GIS software as an additional GIS application. The geographical relation between the distribution network and the customer service entrance can be developed as part of the data take up of mains records. This with the addition of a link with the customer name and address from the Customer Information System (CIS) records provides the customer network link information and enables all geographically related tasks to be managed from essentially one application. The frequency of maintenance requirements of this link are relatively slow and can be satisfied by a batch transaction. The only missing data is the status of any circuit element which maybe operated under protection, SCADA or by the field crews directed from the control room. This information and thus the link to the GIS data model must operate at SCADA transaction speeds. In practice the GIS database were not designed for such transactional speeds and suffered from unacceptable performance when there was a significant penetration of real-time control. The performance was improved by moving the connectivity model onto a separate server mirroring any related changes to the GIS database, however the fast data link with SCADA still has to be maintained with the dedicated server. GIS Centric solutions have been implemented where very limited penetration of real-time control exists and the control room management function is in the majority GIS based. Thus all network data changes and extensions are within the frequency of most GIS database amendments. B.

SCADA Centric:

The second solution has been developed where the outage management process is dominated by real-time information. This information will precede any customer’s knowledge of an outage on the MV network and hence his trouble call. Thus the trouble call process is more to maintain customer relations and association with the outage during the isolation and restoration process. However for any fault on the LV network undetectable by the SCADA the trouble call will provide invaluable information about an LV outage in a similar manner to the GIS centric solution. SCADA centric solutions also use a separate server (redundancy optional) that is synchronized with the SCADA runtime database in real-time. Any changes made to the SCADA database through switch status changes or by the operator as a manual change (temporary network change or as a data engineering amendment) will immediately update the trouble call server. The less frequent changes to the customer network link and customer information are implemented as regular batch transactions through the SCADA data engineering amendment mechanism interfaced to the CIS. In this type of solution the LV model is usually kept at a simple parent child relationship allowing customers to be associated with a supply point which in turn is associated with a fuse on the LV busbar of the customer substation /distribution transformer. In conclusion both solutions have moved to using dedicated servers for the trouble call application to ensure adequate performance. It is the penetration level of automation and the desired detail of LV representation (connectivity) that is realistic to maintain that are the main issues. Any DMS implementation that will be adding significant feeder automation should consider a SCADA centric solution not only from the real-time aspects but due to the regular amendments to the DMS data base as the operator brings on-line automated MV switches. Also many distribution control centers 196

operate with orthogonal schematic diagrams thus the only advantage of geographical diagrams is for crew management. Geographic background maps can be either loaded as an additional display or accessed directly from the GIS through modern cross navigational features now readily available in most DMSs. Fourth Priority – Decision support Applications – constrained Constrained decision support is possible when the network loading duty levels can be determined through load flow and fault analysis of the system. Such applications require in addition to topology, accurate information on the network element descriptive parameters such as impedance, capacity and most difficult to obtain, loads. This analysis can be integrated into the unconstrained decision tools to test the network loading at each step. Typical decision tools that are available include; · · · · · ·

Operator Load Flow Fault Level calculation for circuit breaker duty analysis Constrained FLISR Loss Minimization, optimal switching and load balancing. VAR Control Voltage Optimization

They also provide important data for Condition Based Maintenance of Network Assets. Data Dependency and Sustainability All DMS implementations are dependent on certain levels of network data for both the dynamic (real-time) and the static devices. This data is continually changing and thus an efficient data engineering system must deliver changes to the “as-built” system rapidly and the real-time system must be able to accommodate the operator implementing permanent changes in a timely manner on the run-time system. The more ambitious the decision support tools the greater the data dependency and resources to sustain the applications. The incremental benefits and the data complexity/sustainability are pictorially depicted in the figure below. Incremental Economic Benefit and Data Complexity/ Sustainability Index against data requirements for different decision tool applications. The above discussion highlights some of the issues that must be resolved as part of the DMS implementation strategy and requirements definition to avoid creating a wish list that could generate a DMS outside both budgetary limits and operational practicalities. I.

Basic SCADA Functionalities :

This provides for real time monitoring and control of the power system network with the following functions. -

Data acquisition - Furnishes Status information and measurands data to the operator

-

Control – Allows the operator to control the devices eg., Circuit Breakers, Transformer Tap changers etc., from a remote centralized location.

-

Data processing – includes data quality and integrity check, Limit check, analog value processing etc.,

-

Tagging – Operator identifies any specific device and subjects to specific operating restrictions to prevent from unauthorized operations. 197

-

Alarms - Alerts the operator of unplanned events and undesirable operating conditions in the order of their severity and criticality.

-

Logging – Logs all operator entries, alarms and selected information.

-

Trending – Plots measurements on selected scale to give information on the trends eg., one minute, one hour etc.,

-

Historical Reporting – To save and analyse the historical data for reporting, typically for a period of 2 or more years and to archieve.

II. Distribution Automation / Management functionalities The following functionalities form core of the Distribution Management system. -

Integrated Volt Var Control Network Geographic Information system Load control and balancing / scheduling Facilities Management Trouble-call management systems Operator Load Flow Fault Localization, Isolation and System Restoration

Integrated Volt Var control One of the most important requirement of any distribution system is to provide a good voltage profile / voltage within acceptable limits to the consumers and minimize distribution losses. This is achieved by injecting the required reactive power at the appropriate locations in the network by installing shunt capacitors and voltage regulators on the distribution feeders and controlling them from the central location. The location and capacity of capacitor bank and voltage regulators can be decided using optimal minimal loss strategy while simultaneously satisfying the max/min voltage constraints on the feeder. The on-off switching commands for the capacitor banks and the raise-lower commands for voltage regulators will be issued from the central location. The analysis of the resulting situation is carried our by the system giving the revised voltage profile of the network.

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Network Geographic Information system Network GIS is a core function for both Distribution System Planning Studies and real time control / monitoring of Distribution Systems. The Distribution Systems are widely spread to the nuke and corner of the area and have a large number of network elements. Further the System is dynamic and continuously changing in nature as new customers are added and new Facilities are installed every day. Each network element has a large attribute data. The Network GIS Package enables to capture all the details of the facilities and display them to provide a conceptual view of the location of the facility and also monitor the maintenance, outages and performance of the facility. Load Control, Balancing & Scheduling: The aim of the function is to form minimum network loss configuration and also balance the loads on the substations and feeders such that none of them are overloaded beyond their capacity. In respect of substation the continuous rating of power transformers and thermal loading limits of feeders is considered as the capacity of the substation. The network control function helps in better utilization of distribution facilities (transformer and feeder capacities) This increases life expectancy of the equipment. The application determines switching status of the switches to ensure the best voltage profile and also minimal losses in the network while distributing the total load of the system among different feeders in the network such that none of the substations or feeders are overloaded. RTUs are provided at the substations for data acquisitions of the network, loading and status of the devices. One of the requirements of the power system operation is to ensure that, generation and load demand are balanced under normal and emergency conditions. If at any time, the generation is less than the load demand, the frequency falls and may possibly lead to tripping of individual generator units due to loss of stability. This reduces the available power even more and may ultimately result in collapse of the electrical power system grid. This process takes place in a very short time and manual intervention by the load dispatcher is difficult. A total collapse of the network can be prevented by planned automatic load shedding program. The load shedding function not only prevents network collapses, but also increases the network stability and the power quality considerably. This application identifies the sheddable feeders in a systematic and scientific manner. 199

Asset Management / Facilities Management The Asset Management / Facilities Management ( AM/FM) is generally an integral part of the Network GIS system. The AM/FM Package enables to capture all the details of the facilities and display them to provide a conceptual view of the location of the facility and also monitor the maintenance, outages and performance of the facility. The creation / population of AM/FM package requires a lot of effort on the part of utility, but it improves dramatically the also minimizes the cost of maintenance The AM/FM provides an exhaustive database of the equipment / devices / facilities owned or employed by the utility. The FM provides for recording the Technical Particulars of the facility, Periodical preventive maintenance carried out on the facility and outages occurred on the facility. The above data on the facilities enables the engineer to take effective steps to improve the availability of the facility and reduce the mean time between failures. Trouble call management system In a practical environment of power system operation, outages are inevitable. Consumers served from distribution system vary from homes with lighting load and small motors to complex loads, life saving hospitals, the chemical processing and hazardous industries. In the present day context, outages are not just an inconvenience but can also seriously affect production at all levels of commercial and industrial establishments. Hence when outages occur, the need for accurate and timely information is essential. Dispatch centers need to know precise outages locations and outages crew deployment in order to direct work crews to the location and restore supply. The TCMS application analyses the calls entered and identifies the possible faulty device, keeps a track of crews available and directs the crews to the location for quick rectification of faults. The application provides timely information to the consumer on the status of rectification and also helps to reduce losses due to long interruptions and improve customer relations. Trouble calls are linked to the distribution transformer feeding the customer. The DTR in turn is linked with all upstream protective devices between the transformer and the station bus. Based on this information the TCM software identifies the problematic device and passes this information to the operators on duty for repair. Consumers are kept up to date on status of restoration of their individual outages. This outage and restoration information is retained for post-emergency analysis. Operator Load Flow - Balanced The purpose of the LF function is to provide the complete steady-state solution for a power system network for specified network conditions either in real-time or in study mode. In real time mode the LF function refines the output from the load calibration function by taking the voltage dependency of the load into account. In study mode the LF function can be used to study possible operating situations in order to facilitate the selection of control actions and network operation. In particular it enables the operator to examine the voltage distribution (magnitudes and angles) and the resulting quantities such as branch flows, injections, currents and losses corresponding to a set of operating conditions. All calculated values are limit checked and limit violations are flagged. Fault Localization, Isolation and System Restoration The FLISR-function gives the operator a hand during system disturbance by filtering the incoming system messages and supplying him with diagnosis information and recommendations for remedial actions. The short circuit localization part of the FLISR-function helps the operator to deal with a short circuit swiftly and safely. The faulty region is narrowed down as much as possible so that the operator can take action to eliminate the failure. The isolation and restoration part of the FLISR-function gives the operator a set of recommendations for remedial actions to help the operator to re-establish the power supply for as many customers as possible without wasting time. 200

The FLISR-function is designed as a background function doing its work with a minimum of operator interventions. Mapping of Function vs. Benefit The audits of a typical Indian utility distribution network, its operating procedures and organization structure indicated that improvements can be made in the following areas by the implementation of a DMS facility. These improvements are mapped against DMS functions that produce the benefits. These operating business objectives are consolidated from the introduction into eight categories 1.

Improve reliability and quality at optimum cost

2.

Improve Customer Relationship Management (CRM)

3.

Better knowledge of 11kV network available transfer capacity (improve use of NOPs Normally Open Points).

4.

Intelligent Load Shedding

5.

Timely, up-to-date data on actual system state/performance available to all decision makers (management, planners and operators).

6.

Coordinated documentation and information on network assets.

7.

Streamline business and operating processes.

8.

Reduction of all losses - technical and commercial

The mapping of function and objective are shown in the table below with the following explanations: ·

HV Network covers all the 66 and 33kV substransmission network including all equipment in the grid substations down to the 11kVfeeder header circuit breakers and capacitor switches.

·

MV Network covers all the 11kV feeders outside the grid substation including, line regulators, first and second switching stations (FSWS,SWSS) and other RMUs

·

The number in far right hand column (Obj’ve) corresponds to the utility’s objective number listed immediately above.

·

DOC refers to the Depth of Control leve

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Hyderabad City Distribution Management System The jurisdiction of Hyderabad extends over an area of 1555sq. km including 169 sq. km. of Municipal area. It covers one corporation, the Hyderabad Municipal corporation, Nine Municipalities and 316 villages in Ranga Reddy district and Medak district. For this esteemed Project, ABB employs with finesse, the Industrial IT Solutions for Control & monitoring of the Distribution System to improve the reliability of the electricity supplies to the area covered by the project along with a Management Information System. The approximately Rs. 300 million British Govt. funded project comprises a Distributed Management System covering 18 EHV (220/132 kV ) stations, and around 110 Medium voltage (33/11kV) substations spread over the project area and is centrally monitored & controlled from a Distribution Control Center (DCC) located at Erragadda, Hyderabad. The Distribution Control Centre at Erragadda comprises of dual computer system in hot standby configuration with the associated power supply system to provide uninterrupted power to the computer system. The substations scattered around the project areas are accessed through a back bone or primary communication network - Time Division Multi Access (TDMA) system - for EHV (220 / 132 kv) substations along with the secondary Multi Access Radio (MAR) system for 33/11 kV substations. The Master Control Centre is ABB’s S.P.I.D.E.R. System with three high end servers namely a main and standby redundant SCADA application server pair and one for the DMS (Distribution Management System) application functions. The programmer’s office has three operator’s programming workstations. These are engineering consoles used for database generation, maintenance and modification of existing pictures and / or addition of new network pictures/data. Substation RTUs are provided to control and acquire data from 33kV feeders emanating from EHV substations, incoming 33 kV circuits and 33/11 KV substations . Pole-type RTUs are envisaged for Feeder SCADA and Automatic Meter Reading functions. It is an integral unit comprising of an RTU, Radio Transceiver, equipment power supplies & backup battery supplies 203

The most distinguishing aspect of the Hyderabad SCADA system is the DMS functionalities implemented as an outcome of APTransco and DFIDs visionary quest for a system of the future. It combines a host of functionalities like Load Control, Balancing, scheduling, Volt-Var Control, Facilities Management, Automated Mapping, Trouble Call management system, Automated Meter Reading, Fault localization, Supply restoration etc., implemented on the base supervisory control functionality. The future There is an imperative need for solutions to optimise efficiencies within the existing system. Globally, distribution automation by utilities has shown that it pays for itself in a very short span of time. Already, there is a growing realisation in India that SCADA systems will have a significant impact on distribution control applications and the way enterprises manage, or will manage, their business to stay competitive. Quite of few of the SEBs and most of the newly formed distribution companies are increasingly looking at SCADA to provide solutions ensuring efficient distribution of power across their respective territories, despite financial and communications infrastructure constraints As we evaluate the application of Distribution Automation to the utility distribution system, we must concentrate on economic solutions to the problems. The solutions must initially be based on options to solve the business problem, not the equipment. As the evaluation process continues, equipment, means, communication systems, software, field devices, and maintenance and operations will eventually be considered. The first step is to focus on solving the business problems that the utilities are facing. Distribution automation will pay for itself. Smart utilities will analyse their potential benefits and apply distribution automation. Solve these problems with Distribution Automation, and Distribution Automation will be vital to the industry. Don’t wait, automate!

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Brief Overview of Southern California Edison Power System in United States of America by Bharat Bhargava Consulting Engineer Southern California Edison Co. Rosemead, CA 91770

Introduction: Southern California Edison (SCE) is the third largest Investor Owned Utility in the United States of America. It serves power to about 4.3 million customers in area about 50,000 square miles in Southern part of state of California, excepting cities of Los Angeles and San Diego. The Company has been in service since 1886 with 118 years of successful operation. I, myself have worked here since 1978. The total assets of the Company are over $ 20 billion, with its market capitalization of over $ 8.0 billion.

Generation and Transmission: Southern California Edison used to be a vertically integrated utility having its own power generation, transmission and distribution systems. The Utility was de-regulated effective January, 1998 and sold about 10,000 MW of its oil and gas generation plants. The maximum peak load reached in last two years is 20,500 MW. SCE now has about 6,300 MW of generation only and has to purchase the rest through California Independent System Operator (CA ISO) to meet its customer demand. The growth rate is between 2.5 to 3.0 percent. The present SCE owned generation has a mix of Nuclear, Coal, Hydro and some geothermal and solar. Most of the oil and gas power plants were sold in 1998 as power was de-regulated in California in 1998. SCE also purchases up to 540 MW of wind power from Independent Wind Power producers. The details of the present generation are given below: Nuclear 2,400 MW (San Onofre 1800 MW + Palo Verde 600 MW) Coal 2,200 MW (Mohave 1460 MW + Four Corners 740 MW) Hydro 1,600 MW (Big Creek system 1200 MW + Hoover etc. 400 MW) Geothermal 100 MW Total now owned 6,300 MW California Public Utility Commission (CPUC), which regulates electric power in state of California, has recently permitted SCE to invest in a new combined cycle power plant. Selling the power plants in 1998 put SCE at considerable risk of high purchase prices and caused financial problems and power shortages. Some of the presently owned SCE generation plants are located 300 or more miles away from the load center. The power to the load center is transmitted by long series compensated transmission lines. The power transmission is mostly by 525 kV AC transmission lines. SCE also imports power on a High Voltage Direct Current (HVDC) system from Northwest United States. This line is jointly owned by SCE, Los Angeles Department of Water and Power (LA DWP) and some other cities in Southern California. SCE is part of the Western Electric Coordinating Council (WECC), which is a Reliability Council of power companies in fourteen western states of America, two states of Canada and northern state of Baja Mexico. The total load of this WECC system is about 120,000 MW and has over 2000 generators. All the power generators in this system operate in Synchronism. The North to South 205

WECC system is connected by 525 kV AC and +/- 500 kV HVDC transmission system from Celilo in north to Sylmar in south (figure 1), commonly known as the HVAC and HVDC Pacific Inter-tie transmission system. The total capacity of these transmission lines is about 4800 MW on AC and 3100 MW on HVDC. SCE also receives power from adjoining area in States of Arizona, Nevada and New Mexico. The total import capability is about 7550 MW, which is co-owned with LA DWP and San Diego Gas and Electric Co. Basically, the Los Angeles area is a major load center with power imports from major hydro generating resources in North western United States and Coal, nuclear and combined cycle resources in Arizona, Nevada and New Mexico. The Transmission lines are long, often up to 280 miles, and are mostly series compensated heavily up to 70 percent. The SCE Hydro generation is located in Big Creek area (1200 MW) and Hoover (300 MW) which are about 300 miles from the load center. The power from Big Creek is transmitted by four 230 kV transmission lines and from Hoover by 230 kV and 525 kV transmission system. There are some other smaller hydro power plants about 100 MW total located about 200 miles from the load center and the power is transmitted on 115 kV sub-transmission system. Figure 1 shows the major Transmission into California and generating facilities.

Transmission and Sub-transmission lines and substations: SCE has extensive investment in its transmission and distribution system. Transmission system serves as power resource from remote areas as more and more generation is being added in neighboring states of Arizona and Nevada. It will also help in encouraging competition in power prices and keep them stable. lThe transient stability of the overall system is a challenge. Faults on the transmission system are rare, but are often caused by forest fires. Faults are cleared in four cycles on 525 kV and 230 kV and presently no high speed re-closing is being used. Sub-transmission lines have longer fault clearing time. Details of SCE transmission, sub-transmission and distribution lines are given below. Most of the distribution is on 12.47 kV voltage level. Transmission/Distribution Voltage level 525 kV 230 kV 115 kV 69 kV 33 kV & Below

Miles of Transmission Line: 1,276 miles 3,497 miles 1,944 miles 5,343 miles 91,000 miles

The 525 k/ 230 kV Transmission substations called AA substations have two to four 1120 MVA 525/ 230 kV single phase transformers. There are 9 AA substations with a transformation capacity of about 16,000 MVA. After de-regulation, the generation pattern is not as predictable as before and additional transformation is being added. Voltage support and power factor correction is provided by about 3000 MVAR of recently installed shunt capacitors on the 230 kV system in the Los Angeles area.

206

Figure 1: SCE major transmission lines and generation. The number of substations for different voltage transformation levels are: Voltage level 525 - 230 kV /115 kV 230 - 69 kV or 115 kV 69 - 16/12.47/4.16 kV

No. of Substations 9 40 855

The sub-transmission is mostly 69 kV, but SCE also has 115 kV and 33 kV sub-transmission systems. The sub-transmission systems are mostly fed from two 280 MVA 230/69 kV substations called A substations. Some major substations may have up to four 280 MVA transformers. There are 28 sub-transmission substations in the SCE system. One more is being added in year 2005. Most of these substations have a "Breaker and a Half" bus arrangement. The circuit breakers in the substations are monitored by "On-Line Breaker Monitoring (OLBMs) devices which check the breaker 207

performance during each opening or closing operation. The 69 kV and 115 kV sub-transmission lines are mostly constructed using wooden poles. Shunt capacitors are used extensively to correct the power factor to as close as possible to unity near the load at the substation. The sub-transmission substations have two to four 30 MVAR shunt capacitor banks at each substation. Voltage control is by on-line transformer taps and shunt capacitors. Voltage variations are maintained less than 2 percent. The frequency variations do occur for loss of major generating units in WECC system but are below 0.5 percent or less than 0.3 Hz on 60 Hz. Loss of a 1270 MW, which are the largest generating units in the WECC system result in a frequency decline of about 0.2 Hz

Distribution substations: The distribution substations called "B" substations, are 115/12.47 kV or 69/12.47 kV with two to four 28 MVA transformers. A maximum of two 28 MVA transformers are operated in parallel to limit the short circuit duty below 20 kA on the distribution circuits. The transformers are protected by one set of breaker on the high voltage side. There are six to twelve 12.47 kV distribution circuits connected for each 2x28 (56) MVA transformer bank unit. The circuits were designed for a maximum of 600 amperes feeding typically 6.5 MW power, but in some cases are being increased to 1200 amperes. The distribution system uses "Operating and Transfer bus system" on the 69 or 115 kV side. Each substation is fed by three to six 69 kV or 115 kV sub-transmission circuits. Adequate shunt VAR compensation up to 12 MVAR at 12.47 kV bus is provided for each transformer bank. The feeder and transformer protection is being replaced under the Substation Automation program. The new relays are mostly ABB digital TPU/DPU relays. The distribution 12.47 kV circuit breakers are of out door type, with control cubicles and relays in control room. The digital relays communicate the system information such as voltage, currents, power, reactive power or power quality related information to the Grid Control or Regional Control Center. All transformers, in general, are loaded up to 130 percent of the transformer name plate rating. Extensive analysis called the "Heat-run analysis" is conducted to ensure that all the equipment such as the disconnects, cables, transformer bushings etc. have adequate current ratings. For loss of one transformer, the other transformer can be loaded up to 145 percent of the name plate rating for two hours. This time is adequate to arrange transfer of load to nearby substations. The planning is done based on maximum loading occurring at the highest temperature as the loads are very dependent on the temperatures and they occur during hot weather. The system is also designed to withstand the short circuit currents and adequate analysis is done for ground faults and ground grid design.

Distribution system : SCE serves about 4.3 million customers in 50,000 square miles. The customers are served by overhead and underground distribution systems. The distribution circuits are constructed using wooden poles mostly. Recently there has been a move to start using tubular steel poles or concrete poles. Most of the new construction is underground. The distribution is on 12.47 and on 4.16 kV systems in the old area. A cluster of 6 to 20 customers homes are fed from a 7.2kV/240 volts distribution transformer. The distribution transformers are from 25 kVA to 100 kVA size. The distribution circuits are mostly four wire grounded systems. The distribution transformers may be connected phase to ground or in some cases phase to phase. They are fuse protected. Balancing load on the distribution circuits is one of the big challenges. The transformers may be pole mounted or installed in the under ground vaults called the "burd transformers". Extensive use of auto-reclosures is made to reduce the Customer Minutes of Interruptions (CMI). Efforts are under way to automate substation circuits as well. Communication with the field equipment on the distribution circuit is a major challenge. The distribution system also has pole mounted shunt capacitors to correct the power factor of the distribution circuits. These capacitors operate generally on the voltage at that point. 208

The SCE distribution system has: • 40,000 field Switches • 650,000 Transformers • 1,460,000 Poles • 90,000 Circuit Miles of distribution circuits • 290,000 Underground Structures • 11,713 Cap Banks • 719,000 Street Lights Extensive use of analysis of load, the expected loading at the substation at the system or substation peak and ways to meet the demand if some equipment fails is done every year before the peak load season. Most of the construction or the system additions have to be completed before June 1 of the year. The peak loads are expected any time during June, July, August or September. SCE system has a very high degree of industrialization. There are lot of refineries, major industrial loads, defense manufacturing and some high tech industry. The Los Angeles metro area is the second largest metro area in USA. Some of these customers are very sensitive to power quality. The system is designed to provide the best possible power quality. There are power quality experts who work with the sensitive customers to provide high power quality supply. The typical system load distribution is: Residential Industrial Commercial

30 percent 40 percent 30 percent.

Southern California having relatively warm climate and has lot of air-conditioning load. It is a summer peaking system. It can be a challenge to meet these loads during summer as it increases the power and the reactive power demand and the need of system voltage support. SCE has a big program to automate the distribution substations. This is expected to reduce costs and reduce CMIs. A major substation automation project has been in progress since 1996. There are 855, 115 kV or 69/12.47/4.16 kV distribution substations, out of which 300 substations have been automated. Satellite communication is being used extensively to transmit data from remote locations. SCE also has an extensive IT network for control and monitoring of the SCE power system. Most of the original telephone SCADA system communications are being replaced with the State of the Art technologies. Efforts are also under way to automate the SCE distribution system and the feeder switches, capacitors and other controls.

Safety and Reliability These are two prime indicators on which the performance of the Division and the Company is measured. These are called the KPIs or "Key Performance Indicators". SCE maintains a very reliable level of service to its customers. SAIDI is less than 60 minutes per year and SAIFI less then 2 per year in last eight years. Most of the breakdowns or supply failures occur during wind or rainstorms. Construction and maintenance crews have the tools and fully equipped trucks to respond to such breakdowns very efficiently. There were power shortages, however, in 2001 after deregulation. There was a major WECC system disturbance in 1996, when Southern California Edison lost about 7500 MW of load. New technologies using Synchronized Phasor Measurement Systems (SPMS) are being developed to monitor system phase angles and the system stress and avoid such blackouts in future. Dynamic voltage support using Flexible AC Transmission system (FACTS) is another issue being looked into to increase the reliability of the over all system

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For safety, every SCE employee has to attend a safety training class three to four times a year. The accidents are well investigated and actions taken to prevent there re-occurrence.

Bharat Bhargava Mr. Bharat Bhargava is a Consulting Engineer in the Technology Integration group of Transmission and Distribution Business Unit of Southern California Edison Company in Rosemead, California where he has worked for the last twenty-six years. He is actively involved in transient analysis and power system studies such as SSR, System Dynamics, Power System Stabilizer, Power Quality, Railway Electrification and capacitor switching and Insulation Coordination studies, etc. Mr. Bhargava has been involved in several research projects such as the NGH SSR protective device, in procurement, installation and testing of an Energy Source Power System Stabilizer for a 10 MW/ 40 MWH Battery Energy Storage System at Chino Substation and Alamitos Generating station. He is presently involved in Phasor Measurements Technology, Substation Maintenance Data Analysis and FACTS projects, etc. He was a member of SCE Transmission -2010 Team, which evaluated new advanced technologies for increasing SCE asset utilization. Mr. Bhargava graduated from Delhi University in 1961 with a Masters from Rensselear Polytechnic Institute in 1976. He worked with the UP State Electricity Board in India from 1961 to 1975. Mr. Bhargava is a Senior Member of PAS, IAS Communication and Vehicular Societies of IEEE and a Member of CIGRE.

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Distribution Management – Metering, Billing & Revenue Realisation by R. C. Gupta Vice President, Desein Private Limited Introduction Today, each of us criticises the existing set up and abuses the working of various distribution utilities. To some extent, utilities deserve that also. It is easier to deliver talks on “Work smarter” than getting the work done. But with the right tools, Utilities can empower their work force to achieve new levels of productivity and performance in the field. Field service represents a clear area of opportunity to achieve significant gains in both operational efficiency and customer satisfaction. These benefits can be reaped by automating the various processes. The field service activities can be transformed in much less time and for far less money in comparison to other competing systems, by using modern technologies viz. the power of wireless communications, the Internet, and realtime data exchange etc. Specific workforce management and field service solutions based on web-based technology are today available. These solutions, unlike other systems, do not require purchase and maintain too expensive computer equipment to get the job done. Within a short span of time of introducing such systems, field workers will be working smarter, communicating over the Internet, balancing workloads and tracking job status in real time, with no paperwork. This will definitely improve field service operations, resulting cost reduction, improved operational efficiency, reduced overtime, improved customer service and emergency response. Introducing the concept of Mobile Workforce Automation, comes next. Workforce Automation includes the utilization of wireless, Internet, web-served mobile communication and field service dispatching solutions in managing mobile resources. With its rapid implementation, field staff uses the system productively faster, reaping the benefits of wireless communications sooner, and generating money saving quicker than from any other commercial system available today. Challenge When load drives over half the utility’s cost structure, shouldn’t access to reliable load data be an enterprise challenge? Energy data is the essence of a distribution utility. Back office and front office operations rely on the multiple sources of meter data. It seems logical that the users may have centrally accessibility to reliable data, but it is far from reality. Volumes of data and systems are the norm and with those, come the burden of patching, integrating, manipulating and maintaining multiple source systems, plus the potential for errors and confusion as the frequency of data collection and intervals increase. Solution It is therefore essential for utilities to develop a fully integrated solution for data collection, meter data management and information distribution. The Meter Data Management Solution is the system of record for metered consumption in an open, flexible, and extensible platform. System of record means that the data contained in the warehouse contains actual reads, an audit and the final consumption data that was used for revenue billing calculation. The Billing and Electricity Meter Reading operations in India has gone through 3 distinct phases: a) Manual Meter Reading and billing by batch processing b) Spot meter reading and billing c) Hand Held devices for meter reading and Billing at Customer Premises. Normally, utilities in India are using the first method. All the three methods have many loop holes. The major problem is vast scope for data manipulation in the first method of manual reading & batch processing of bills. In 211

Spot Billing & Cash Collection, consumer needs to go to a spot billing center with his reading and get the bill processed based on that reading. There is tendency of consumers not to take trouble to go to spot billing center, though these are located in their localities. While talking of use of HandHeld devices, where in a meter reader goes to consumer premises, takes reading and transfers it to host computer in the evening for billing. This solution reduces the billing cycle by 15 days but is still prone to data manipulation because the data in the hand held can be easily manipulated (thru a simple C program). Besides, meter readers cannot be tracked in the field (Meter readers can sit at home and extrapolate past bills). The solution, therefore, lied in automation of meter reading operations. Automated Meter Readings (AMR) AMR helps the consumer and the utility access to the latest and accurate information from the metering devices and also provides savings in time, manpower and helps efficiency and energy management. AMR solutions are very simple to implement and provides immediate benefits. This sort of solution for meter readings require the installation of ERT (Encoder/Receiver/ Transmitters). ERTs are radio-based modules that fit into electric meters. The ERTs encode consumption and tamper information from the meters and communicate the data via radio to radio data collection systems including Handheld, Mobile AMR and Fixed Networks. ERT modules can be retrofitted to existing meters or installed on new meters during the manufacturing process. Electric ERTs are installed under the glass of new or existing electric meters and are powered by the electricity running to the meter. A few solutions in use are described below.

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Off-site Meter Reading (OMR) Off-site Meter Reading uses radio-equipped handheld computers to read ERT module equipped electric meters via radio without the need to access the meter or customer premise. A radio is integrated into a handheld computer. A software module in handheld computer determines which meters are to be read by radio vs. which are read manually. As a meter reader walks a route, the radio-equipped handheld computer sends a radio signal to nearby radio-based meter modules that have been installed on meters. The unit then receives meter reading and tampering data, from the meters. OMR is normally used to read the 5-10 percent of accounts within the utility service territory that have high-cost or hazardous-to-read meters. The meters are typically located either in a geographically dispersed environment, or situated in a basement or with an angry customer who doesn’t want the meter reader on the property. Thus, the OMR eliminates access problems, improves meter reading and billing accuracy, thereby resulting in customer satisfaction. Besides, it also improve efficiency and safety of meter readers. Mobile AMR Mobile AMR uses vehicles equipped with radio units to read ERT module-equipped meters via radio without the need to access the meter. A radio transceiver, called a DataCommand Unit (DCU) or a portable DataPac (DP), is installed in a utility vehicle. Route information is downloaded from the utility billing system and loaded into the radio transceiver. While driving along a meter reading route, the transceiver broadcasts a radio signal to ERT modules within range to upload meter reading to the billing system for bill generation. Mobile AMR is usually used in saturated areas where there may be large populations of difficult-toaccess or hazardous-to-read meters. A single DCU transceiver reads an average of 10-12,000 meters in an 8-hour shift and can read up to 24,000 meters per day, depending on meter density. A DP reads an average of 4,000 to 5,000 meters per day. The Mobile AMR system can read the same ERTs as the OMR system. Fixed Network AMR Fixed Network AMR uses a fixed radio communication network to collect data from meters equipped with ERT modules and transports the data over a wide-area communications network to a central host processor. A fixed, radio-based communications network is installed over meters equipped with meter modules. The network components include a Cell Control Unit (CCU), Network Control Node (NCN) and Host Processor (HP). The CCU is installed on power poles or street light arms. It is a neighborhood concentrator that reads meter modules, stores data temporarily and transfers data to the host processor for billing. The NCN is a regional concentrator installed in substations. The primary function of the NCN is data transfer from CCUs to the host processor. The Host Processor is the head-end host processor. The software is resident on host processor which manages the collection of data from the network devices to transfer data to a database for storage, retrieval and further processing. The same ERT meter modules read by an OMR or Mobile AMR system can also be read by the fixed network. The various advantages of the system includes reduction in meter reading staff, Improved accuracy and efficiency, distribution planning, Asset management etc. MicroNetwork AMR The MicroNetwork solution combines radio and telephone technology to collect metering data from groups of electric meters to read from groups of meters in a variety of environments. The MicroNetwork consists of ERT meter modules, locally installed communications nodes called Concentrators with meter reading software and host processing station. Using RF communications technology, the Concentrator Units automatically gather meter reading from meters equipped with 213

ERT meter modules. The MicroNetwork then employs existing public telephone networks to send the gathered data from the Concentrator Units to the host processor. MicroNetwork reads from the same meter modules as OMR, Mobile AMR and Fixed Network AMR. AMR solutions using open technologies The recent developments in AMR applications, uses internet. The data is transmitted from meters to the desktop applications or Data Collection Servers that collect the information using multiple open technologies such as FTP (File Transfer Protocol), SMTP or e-mail (Simple Mail Transport Protocol) and TCP/IP (Transmission Control Protocol / Internet Protocol). The data is transferred using the internet and the customers Network. The meter needs one of the ports open for outward data transfer : Port 25 for SMTP/email, Port 21 for FTP/file transfer or Port 80 for HTTP/web browser access. An Ethernet port is embedded in the electric meter to transmit the stored data over the network for Automatic Meter Readings. The embedded ethernet port provides a very cost effective way of sending the information to the end users or to the database servers. The network is always on connection that provides data streaming and data is transferred over the network via TCP/IP, SMTP and FTP. Scenario in India In most of utilities/public sector under takings in India, the traditional method of manually recording of meter readings is in use. While introducing power sector reforms in recent past, Hand Held Computers are being put to use for meter reading operations. The methodology requires the meter data to be down loaded to hand held device with which meter reader goes door to door to record meter readings. These readings are transferred to host computer in evening to prepare consumer bills. The meter data for next set of consumers is again down loaded for the next day operation of the meter reader. The limitation of the system is that meter data of maximum 2000 consumers can be taken care of, by the hand held computer. In this process, there is time lag of at least 15 days between meter reading and bill serving operations. As an enhancement of the concept, billing software can be loaded on hand held device to process bill and to print the same on 20-column printer. The main draw back of the system is that the data can be manipulated as the hand held computer uses lower version of C language. Besides, there may multiple meter readers in the field. Each may be having a hand held device. There is possibility of not having the same version of billing software in all the devices, thereby resulting in generation of wrong bills. It is also a cumbersome process to down load and upload data between hand held device and host computer, every day. On Line Billing System Keeping the problems faced in use of hand held devices for meter reading/spot billing and with the advent of introduction of CDMA phones in India, CDMA technology is being introduced for its faster revenue generation using Hand Held Terminals. CDMA is the world’s fastest-growing wireless technology, with high speed data transfer over a wireless network. Using a unique code to distinguish each different call, CDMA enables many more users to share the airwaves at the same time. CDMA technology provides point-to-point wireless data communication, much better and cost effective quality, privacy, system capacity and flexibility than other wire line technologies. Beside, the enhanced services such as short messaging, e-mail and Internet access provided by CDMA technology are added advantage. Concept The staggered billing data generated by Spot Billing Machine in the field can be transmitted to the Central Server through the connected CDMA modem for near to online data management. The online data link capability can also be used for online bill collection through Cheque / Credit Card payments. The system once implemented will be very useful and faster revenue realization, cost effective billing process and real data networking. Based on the this concept, a model was conceived as per following illustration. 214

Proof of Concept For viability of project, PDA was used as hand held device. A portable printer with blue teeth was employed for printing of bill at the consumer premises, in his presence. Reliance CDMA phone was used to connect PDA with the host computer thur internet. Initially, the meter readings were taken in the same locality where the host computer was located. Later, it was tested to produce bills at the spots 250 KM away from the host computer. No data or billing software was resident on hand held PDA. The data viz. consumer number, meter reading etc. was entered by meter reader into PDA to transmit the same to host computer for bill calculation, on the basis consumer information in the data base of utility. The bill information received at PDA from the host computer is printed in front of consumer in the form of a bill, which is served to consumer. The experiment gave confidence to even attach a credit card reader with PDA so that the payment may be accepted thru Credit Cards. All the data entered on PDA is transferred to host computer to update consumer data at the Utility’s data base.

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Advantages of Proposed On-Line Billing System There are many benefits of the online billing system, using hand held device. A few of these are given below : · authentic & accurate Meter Readings · 100% Meter readings · Master Data to reflect field reality · Rudimentary Energy Audit · Reduction Of Interest Rate Burden · Quicker Updating of data for cash collection, Call Center Operation etc. · No Data on hand-held, avoiding chances of manipulation · Same copy of billing software being used by all the hand held computers in the field · Constant monitoring of Meter Readers by Supervisors · Date, Time and Meter Reader code recorded automatically with meter reading · No operational errors as no uploading & downloading of bills calculated on handheld device to central server. · Instant posting of billing data in ledger maintained at server · Route mapping automatically created On-line solution v/s store & forward allowed by hand-held devices · House to house metering will identify meters where consumer numbers are not available on master-data · Identification of houses without meters, for follow-up by vigilance department · Ensures proper billing of newly installed meters- prompts will be sent if master-database not updated · Prompting defective meters/tampering of meters- for quick action by vigilance department RELIABILITY Generation of Bills and transfer of Billing data to utility’s Server should not get interrupted. The following measures are kept in view for the same. · · · · · · ·

If CDMA phone connectivity fails, Handheld device has facility to store data downloaded from PC. This will provide 100% service level. Bandwidth is assured by CDMA Service provider Device Failure thru standby handheld computers Human problems thru assistance to meter readers by the supervisors Training of field staff to take care of eventualities Service Failure thru the constant vigil by the System Administrator Network availability thru leased connection from established service providers

QUALITY OF SERVICE For enhancing the accuracy of bills and to ensure consumer satisfaction of quality service, the measures embedded in the system are : · · · · ·

System Software is proven IBM product & application software developed by experienced system engineers Error Free Data entry of meter reading thru Software validity check facility and Duplicate feeding Tamper proof: Password assigned to each meter reader as Meter reader name, date and time of meter reading automatically recorded Tariff Rates will be incorporated and is in the Billing Software, a single copy of which at host computer. This is shared by all hand held devices in the field. Bar Code software in the HHD is a proven application, and helps in revenue receipts

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Evaluation of On-Line Billing System –Cost Benefit Once the online billing system is implemented, there will be tremendous savings due to the following: These savings are to be measured and net cost benefit ratio is to be worked out. · · · · ·

Savings from Data Integrity: Savings from 100% metering Savings from real master data Savings from basic energy audit Interest Savings

Online Billing will be a paradigm change - Real-time Interactivity Introduces a quantum shift from store & forward methods equivalent to shift from Telegraph to Telephones , E-mail to Internet etc. Conclusion Work Force Automation Technology provides real-time data to the staff in the field and uses wireless communications and the Internet It enables supervisors to automate the scheduling and scheduling of work and more effectively track and monitor the status of field service operations. Employee productivity and customer satisfaction increases while the costly paperwork and time associated with traditional manual work is reduced. This technology results in improving efficiencies and work culture, besides savings in time and efforts in the field and also, in the office. For an electricity utility, the technology is not only useful for meter reading and billing generation, but may also be used to track installation of meters and removal/change of meters. Utility’s commitment for using innovative new technologies is a must to improve business operations. This enhances customer responsiveness, improves field operations and leverages the return on investment.

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On-line Fault Detection Algorithm for Three Phase Radial Distribution Networks G. Akila Prof. S. P. Reddy II Year M.E (PSE) Head of Dept (IT) Crescent Engineering College, Chennai-48, India.

ABSTRACT : Distribution networks may not to be provided with protective devices or circuit breakers in each branch of the feeder. Faults are the abnormal events that occur in distribution feeders. The conventional protection scheme provided in distribution networks is not capable of detecting them. Usually they are identified only when the consumers report the loss of power. Hence the purpose of speedy repair work and maintenance, it is important to find out the exact fault location and type of fault. So we developed an algorithm for find out the fault location and type of fault. This algorithm detects the fault location and type of fault in on line under normal and peak load condition based on the three phase measurements obtained for state estimation.(1).for finding out the fault location, from the feeder diagram & measured data we calculate the fault power and fault current in each node. under operating conditions in the presence of some fault, the measurement data are expected to be abnormally high currents in the fault path and beyond the fault location the current measurements are low or close to nil. So fault location is the node where the high values become low. then we compare the on line data with the stored one and find out the node which reads zero power.(2).for the type of fault we fix some threshold value for each type of fault. Then comparing this threshold with fault power we easily find out the fault location. For the above requirements, the conditions are framed and program was written in C++.

INTRODUCTION : An electric power system should ensure the availability of electrical energy without interruption to every load connected to the systems. When the electric power supply extended to remote villages the power systems would of several thousand kilometers of distribution lines. The high voltage transmission lines carrying bulk power could extend over several hundred kilometers. Since all these lines are generally overhead lines are exposed, there are many chances of their breakdown due to stroms, falling of external objects, and damage to the insulators etc.these can result not only in mechanical damage but also in an electrical part. Distribution networks may not to be provided with protective devices or circuit breakers in each branch of the feeder. Faults are the abnormal events that occur in distribution feeders. The conventional protection scheme provided in distribution networks is not capable of detecting them. Usually they are identified only when the consumers report the loss of power. Hence the purpose of speedy repair work and maintenance, it is important to find out the exact fault location and type of fault. So we developed an algorithm for find out the fault location and type of fault.

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THE APPROCH :

Read measurement data

State estimator

Bad data detector

Abnormal data

Fault detector Figure 1: Basic Blocks of State estimation The state estimator reads the measurements data. The bad measurement data are detected by the bad data detector. State estimator, computes the voltage magnitude and phase angle at all the load buses from the available real time measurements. If the data is abnormal, or protective device operation is noticed, then the data goes to the fault detector. The abnormal data are compared with the normal measurement data. A reasonable threshold value that is crucial is used to detect the fault path. For developing this algorithm we take 33/11kv tiruchendur substation, which having two feeders such as, (1) tiruchendur 33/11kv Town feeder. (2) tiruchendur 33/11kv Sangivilai feeder. With this feeder diagram we also collected the data such as line impedance, transformer impedance, transformer ratings and distance between each transformer. These are shown in the following diagram.

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BASIC STEPS IN THE PROPOSED FAULT DETECTION ALGORITHM :

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WORK DONE SO FAR : This algorithm detects the fault location and type of fault in on line under normal and peak load condition based on the three phase measurements obtained form state estimation. (1)

for finding out the fault location, from the feeder diagram we fix the nodes & using the measured data we calculate the fault power and fault current in each node. under operating conditions in the presence of some fault, the measurement data are expected to be abnormally high currents in the fault path and beyond the fault location the current measurements are low or close to nil. So fault location is the node where the high values become low. Then we compare the on line data with the stored one and find out the node which reads zero power. That node is exact fault location.

(2)

for finding out the type of fault we fix some threshold value for each type of fault. Then comparing this threshold with fault power we easily find out the fault type. Phase fault indices are initialized for each phase .if the abnormal or high values indices are found in three phases then fault is identified as three phase fault. If the abnormal indices are in only one phase then it is single line to ground fault. if two phases having abnormal indices and another one has normal indices or close to nil value then the fault is identified as line to line ground fault. If one phase has abnormal indices, but flow in one of the phase is in opposite direction then that fault will be line to lone fault.

CONCLUSION : An algorithmic approach has been presented for finding the exact fault Location and type of fault. This was developed using real measurement datas.This will be give a basic idea for distribution automation systems.

LITERATURE SURVEY : 1) 2) 3) 4.)

Distribution automation system with real time analysis tools.-IEEE computer. Applications in power, vol 9, no.2, April 1996. State estimation for real time monitoring of distribution systems.mesut.e.baran,Arthur w.kelley.IEEE trans on power systems Vol 9, no.3, august 1994. Fault section diagnosis of power system using FUZZY logic.IEEE Trans on power systems vol 18, no.1, Feb 2003. On line fault diagnosis of distribution substations using hybrid cause effect network and FUZZY rule based method.IEEE Trans on power delivery vol 15, no.2, April 2000.

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Panel Discussions & Valedictory Address 1)

Sh. Jagdish Sagar, Former CMD, Delhi TRANSCO.

2)*

Sh. N. K. Mathur, Former Secretary, (Communication), Government of India

3)

Sh. F. A. Vandrevala MD, Tata Power Co. Ltd.

4)

Sh. Arvind Jadhav, Joint Secretary, Ministry of Power, Government of India

Veladictory Address Sh. R. P. Singh, CMD, Power Grid Corp. of India Ltd.

* Papers received by the time of compilation

Convergence of Power and Telecommunication N. K. Mathur

Introduction “Convergence of Power and Telecom” – this is a unique topic selected by the organizers of this International Conference. Can there be convergence of such diverse entities and such diverse disciplines? And if so, in what fields of activity? These questions are important for all countries, but especially for this Region where quantum of resources tends to pose limitation. Experts have deliberated in this Forum on several issues of topical interest and more matters are going to be discussed. However, telecom would occupy special place in the deliberations since it is at the focus of almost all activities. It is an honour to address such august gathering. I have tried to keep my presentation at concept level and hence it is possible that some technical aspects are over simplified for the sake of maintaining focus on the concept; the technical details would fall in the domain of power and energy experts. With this introduction, let me formulate the issues pertaining to my subject. The first point to be addressed is : how do we define convergence? Internet offers a good example of convergence of computer and telecommunication technologies to extend to the user the manifold facilities of text, graphics and audio communication from any point on the globe to any other point. On another plane, almost any activity is an example of convergence – dancing encompasses convergence of physical activity and audio effects of musical instruments. The energy sector has already seen convergence on other fronts : · Convergence of electricity and natural gas · Convergence of water and electricity · Convergence of power and telecommunication All these have one factor in common - namely these reach each end-user premises and, through convergence, seek to achieve economies. Convergence is thus the interplay of multiple services and facilities at the level of end-user. It has ramifications extending to such diverse fields as alternative energy sources, shared savings to consumer, de-regulated trading possibilities and at a future date regional grids encompassing geographical areas having abundance of one or the other resource. Convergence involves policy, technological and market dimensions encompassing hitherto separate sectors. The issues have to be looked at from the viewpoint of horizontal as well as vertical aspects. The former would involve content and the latter would be concerned with regulation. Although a few countries have already introduced legislative amendments to take care of these aspects, legislative changes would be necessitated in most other countries in order to give effect to convergence on a global scale – the benefits of which would reach the end-user.

Power and Telecom In so far as power and telecommunication fields are concerned, we shall examine convergence on three levels · Regulatory and strategy level · Techno-economic level · Network management level We have just taken note of the fact that convergence of resources makes it feasible to achieve economies in terms of natural resources, network management as well as the financial front. Although the convergence process is not yet fully developed, the possibilities are enormous and business must reap the maximum benefits. On the legislative front, it is recognized that considerable intersector coordination would be involved. Naturally, regulators are yet to catch up with the possibilities 223

and hence utelcos would have to operate within the parameters of their licensed activities until such time that full integration/ convergence is statutorily permissible. Interaction between power and telecom sectors had been recognized by the US as far back as 1949 when the Rural Electrification Administration was accorded the mandate of establishing source of long term financing to expand and maintain better quality rural telephone systems. In the eighties, Thailand issued a similar mandate to their electricity authority for telecom lines in rural as well as urban areas. I have not been able to discover similar legislative actions by other countries but I understand that UK and Sweden also provide such examples. Let us look at the techno-economic area of power / telecom convergence. We have known about power line communications (PLC) for more than half a century. R&D in this field has indicated how PLC can be further integrated into existing telecom networks and studies have been conducted into economic as well as regulatory issues associated with such deployment. Significant technical progress has been achieved towards high-speed data transmission – 2 Mbps has been found comfortably feasible, which has opened up new vistas of information transfer. Optical fibre for communication purposes is now commonly strung on power transmission towers; several methods of supporting the fibre by the ground wire of the power line have been adopted by different companies. This technique utilizes the ‘right of way’ of the power line to establish optical fibre communication which – as we all know – has almost unlimited capacity for telecommunication, apart from considerable monetary savings flowing from the right of way licence obligations. Power companies undoubtedly have the “reach” to the largest population. The day is not far when the same wall socket of the power company could be utilized for connecting to the internet and a whole range of telecommunication services; the power line network can truly be termed as ubiquitous, and early engineering work has already enabled lossless energy transmission on the same wires. Furthermore, the electric distribution network today can provide the “last mile” for telecom services and this too has immense possibilities if both utilities share the cost of upgrading the electricity distribution network to excellent levels. This could provide the high quality alternative to the faultprone user end of the telecom network. This would then provide, with modern building construction practices, fault- free termination for voice, fax, video and data services – including internet = for all homes. Studies are underway to exploit indoor power lines as high speed local area network (LAN) for data communication, obviating the need for the telecom company to lay wires for such LAN. Work is in progress in the US and E U since this matter is of worldwide interest. Success of field tests in this area affords great hopes for considerable economic benefits: the very idea of internet access from the wall plug is thrilling ! Apart from drastic tariff cuts in internet costs, this global information database would become available over a ubiquitous infrastructure – available to everyone anywhere.

Network Management There is yet another dimension to convergence between these two sectors. This is concerned with the similarity in the network-spread of the two entities – power and telecom. The philosophy and principles of telecom network management are by now quite well established. These have been fine-tuned to the needs of varied geographical terrain, subscriber density, central office technology and transmission styles. Power systems network management could, with advantage, be modelled on lines similar to telecom network management systems – since these factors are mutatis mutandis similar in both entities. However one could first look at the special and distinctive features of the two sectors before examining the commonality scenario. In telecom networks, the network elements and the equipment to manage, namely the central office switches, transmission network and distribution systems are very diverse. The management system must therefore enable interconnection amongst the diverse network elements, apart from achieving inter-operability. Two major protocols have emerged: the SNMP (Simple Network 224

Management Protocol) and the TMN (Telecom Management Network) system. In the power sector, network management has traditionally adopted energy management systems (EMS) based on SCADA (Supervisory Control and Data Acquisition) and utilizing PLC – Power Line Carriers. Historically, the equipment to manage has not been so diverse in nature as in the case of telecom. Hence the SCADA/ EMS platform did not lay much dependence on interface software and, naturally, the protocols were relatively simple. Inter-operability functions were largely performed manually. The process of migration to the telecom network management system has to primarily maintain the SCADA / EMS system as providing the basic functionality. The TMN system is based on ISO layered structure and it is possible to integrate the remote terminal units (RTU) and power network elements into the TMN environment. This has been implemented in some countries for power systems. For example, automatic generation control is treated at service management layer as in TMN and commands are issued depending on enterprise policy. In short, the large experience of telecom system is available to the power sector for adoption in the network management area.

Customer Management Inherent in the network management system is a major aspect – perhaps more important today than it appeared in the past. That is: tele-control of each consumer supply point, which would enable the discom to · ·

monitor the supply level, issue bills and perform other functions of commercial and statistical nature control the flow of power through the meter – connect, disconnect and reconnect the supply

On the whole, such arrangement would result in faster revenue collection, apart from enabling prompt contact between the consumer and the Company. Remote control of telecom service at the customer premises is a well established concept in that sector ever since telephony was put to commercial use. This methodology obviates the need for manual intervention at customer premises, as also it makes the process instantaneous and “ online” with its attendant benefits. However, this is not so prevalent in the power sector where - till a few years ago – meter reading as well as disconnection and reconnection of supply had to require an employee’s presence at customer premises. The power sector is also beginning to adopt the telecom philosophy with the help of remote control procedures. Tele-operation of these activities is already enabling control of HT power connections – disconnection of supply from the central control point. At a future date, such activity would become economically feasible for LT domestic connections too, through the use of intelligent meters, and the control system could be wire-based or based on wireless technology. At that stage, it can be said that telecom has fully assisted power in the area of tele-control of each consumer supply point.

Standardisation One cannot leave the subject of convergence and its inter-connectivity and inter-operability dimensions without taking note of the standardisation aspect. This activity is in full swing at the level of European and American standardisation organizations. Fundamentally, since communication over power network utilizes the same medium, suitable measures have to be adopted to prevent signal radiation at high levels and to ensure electro-magnetic compatibility (EMC). Considerable work is underway in this field and also in the area of spectrum usage. Studies have indicated that PLC can be integrated into existing telecom networks; new opportunities have emerged in the present era of utility de-regulation, as we have seen earlier in this Presentation. Standardization work in India has naturally to proceed in close coordination with international standardisation bodies. For instance, CENELEC technical committee TC. 205 is working on Home and Building Electronic Systems (HBES) to ensure co-existence of access and in-house PLC systems. Mains communicating

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systems fall under the purview of SC.205. Further work is in progress under the power line telecom project of ETSI - the European Telecommunication Standards Institute, and so on. In the international fora, the concept of regional standards is well recognised. The South-Asia and Pacific Region could establish technical standards for power and telecom convergent areas which are best suited to the needs of the Region. In some areas of activity which are specially relevant and of topical interest to the Region, such standardisation could even precede and guide the establishment of international standards.

Summarizing In all this discussion, it is noteworthy that telecom is situated at a central point in all activities pertaining to electricity sector. There is convergence at the physical layer, at the techno-commercial front, in network and customer management and lastly, in the area of international standardisation. Yet, one should not hope to see total convergence in such diverse products as telecom and power. It may not be out of place to mention that full convergence of telecommunication has not yet succeeded even in Information Technology and Broadcasting fields – partly attributable to policy and partly due to techno-administrative reasons. However, in so far as power and telecom are concerned, I am of the view that these discrete entities should co-exist as sovereign entities and function within their respective areas, closely cooperating with each other. Cooperation would be the key to success in the delivery of right product at the correct point. This Paper also attempts to present the need for recognizing the specialised area of power and telecom convergence (possibly named as POWERTEL) which would involve · · and ·

study of the various dimensions of cooperation and synergy between these two disciplines working out economies which can accrue to the power and telecom sectors in this Region evolution of suitable techno-commercial solutions of significance to India and the Region.

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