Reliability Termpaper Indrakmaharjan

Reliability Engineering Concepts in Electrical Power Systems, Power System Reliability (MEPE 519)

Term Paper on Efficient Reliability: The Critical Role of Demand Side Management (DSM) in Power System Reliability

Submitted to:

Dr. Rajesh Karki, P. Engg. Associate Professor University of Saskatchewan

Submitted by:

INDRA K MAHARJAN MEEPE- 3rd Semester

November 27th, 2007

Introduction Background An electrical power system consists of many individual elements connected together to form a large, complex system capable of generating, transmitting and distributing electrical energy over a large geographical area. Because of the Interconnection of elements, a large variety of dynamic interactions are possible, some of which will affect some of the elements, and others will affect fragments of the system, whilst others may affect the system as a whole. The power system must respond to both a changing demand and to various types of disturbances (1). Modern electric power systems are perhaps the most complex large-scale technical undertakings developed by human kind (2). Electricity has become a dominant factor in daily life, an essential input to industrial production and a major form of energy. This has increased more dependency which is further increased with more utilization and increasing demands. Such increasing demand and growing affluence bring the necessity of high reliable electric service. In modern society, the quality of life is closely associated with the availability of electrical energy and has multidimensional impact on the society. Hence it can be said that a modern power system serves one function only and that is to supply customers, both large and small, with electrical energy as economically as possible and with an acceptable degree of reliability and quality (3). Quality refers to supply the energy with frequency and voltage within the prescribed limits. A basic requisite of a modern power system is the ability to satisfy the constantly changing system load requirement at all times. It is impossible to guarantee this ability, and any attempt to do so is impractical and uneconomical. Although the probability of customers being disconnected can be reduced by increased investment either during the planning phase, operating phase or both (4). It is evident therefore that the economic and reliability constraints can conflict and thus lead to difficulty in making managerial decisions in the planning, design and operating phases. Power system engineers have always attempted to respond to the society’s expectations and to achieve the highest level of possible reliability at an affordable cost. Power System Reliability Concepts Reliability is an old concept and a new discipline (5). Reliability is the probability of a device or system performing its function adequately, for a period of time intended, under the operating conditions intended or encountered. It can also be defined as the overall ability of a system to perform its intended function (2-4). The concept of power system reliability is a broad concept and covers all aspects of the ability of the electric power network or system to satisfy the consumer requirement (4, 6). Because of wide ranging implications, system reliability is sub

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divided into two basic aspects of a power system namely system adequacy and system security (3, 4). Adequacy and security are major concern for power system planners and operators. System adequacy relates to the existence of sufficient facilities within the system to satisfy the consumer load demand. These include the necessary facilities to generate sufficient electrical energy and the associated transmission and distribution required to transport the energy to the actual load points. Adequacy is therefore concerned with static conditions which does not include system disturbances. System security, on the other hand, relates to the ability of the system to respond to disturbances or perturbations arising within that system. These include the conditions associated with both local and widespread disturbances and the loss of major generation and transmission facilities. It is known that these two aspects deal with quite different reliability issues and involve different assessment techniques. Most of the probabilistic techniques presently available for power system reliability evaluation area are in the domain of system adequacy assessment. The evaluation of Loss of Load Expectation (LOLE) and Loss of Energy Expectation (LOEE) or Expected Energy Not Supplied (EENS) or Expected Unserved Energy (EUE) indices reside in the area of adequacy assessment. (79).The quantification of spinning or operating capacity requirements falls in the domain of security assessment. The basic techniques for system reliability assessment can be categorized in terms of their application to segments of a complete power systems based upon the functional zones of generation, transmission and distribution. Adequacy studies can be, and are conducted individually in these three functional zones and also can be combined to give hierarchical levels (HL). Adequacy assessment techniques are grouped in HLI, HLII and HLIII depending upon the consideration of functional zones involved in the assessment. The reliability indices calculated at each hierarchical level are physically different (10). Power System Planning Power system planning can be divided into two distinct different areas dealing with static and operating capacity requirements (4). The static capacity area relates to the long term evaluations of the overall system requirements normally with the time span of 10 to 30 years. Operating reserve margin analysis, on the other hand, relates to the short term evaluation of the actual capacity required to meet a given load level or demand (4) with a time horizon of up to one year. With the deregulation of the electric markets power system planning has become a challenging work.

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Supply side planning had been enjoying a key priority in term of increasing reliability of power system since many years. But due to the uncertainties in fuel prices, growing environmental concerns over the conventional energy sources, rapid economic growth, changes in settlement patterns, heat waves and cold snaps are driving the demand for power to new peaks and taxing an already – constrained electric grid. A fundamental imbalance between supply and demand is posing a grave problem to every nation at present. New investments in generation and transmissions are obvious reactions to reliability challenges. This has increased the reliability but the reliability problems in various forms are arising in almost every region of the country. A supply side strategy is undoubtedly justified on both economic and reliability grounds but also requires large commitments of investment capital in generating plants, infrastructures of energy supplies as gas pipelines and electric transmission and distribution lines. This is much worsened by the challenges for natural gas supply, rising fossil fuel prices and instability in regions and substantial environmental costs which must be absorbed or offset through additional mitigation measures. The growing demand and particularly peak load growth is a major threat that has put great strains on power system infrastructure. This has made the achievement of reliability more expensive and the network less efficient. Hence the policy makers are compelled to find other means to enhance efficiency and reliability both. This has led to the consideration of the real reliability benefits that can be captured from energy resources held by customers: efficiency and load management, customer- owned generation, and customer response to market prices.

Efficient Reliability In the present competitive electricity market, electric system reliability is, in many respects, a classic public good i.e. the essential attributes of adequacy, voltage, and frequency are available to all interconnected users simultaneously (11). The most common reason behind the reliability problems is taken as failure to build sufficient new generation, and/or lack of investment in transmission and distribution facilities by the consumers, politicians and the industry. This is overlooking the essential fact that reliability is a function of the relationship among generation, wires, and load and the solution is not really addressing this fact. So in order to contain this relationship in balance, the solution must consider new generation, investment in wires, or accelerated load management and efficiency measures or a combination of the three. So it is needed to invest in cost-effective efficiency and load management and this is the main requirement of present time. Addressing the reliability problem only through “turbines and wire” policy will be unnecessarily expensive and environmentally harmful where as energy efficiency and load management can add enormous value to the nation’s electric system, lowering the cost of electric service, mitigating capacity

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crunches and increasing reliability in a cost effective way in both monopoly and deregulated market (11). Reliability Challenges expose the value of Demand-Side Resources The new economy is a digital or internet based economy which has increased the dependence on electricity and increased the damages caused by poor reliability. Beside this the consumers have seen increase in the number or reliability events as voltage reductions, power alerts, power outages and other system disturbances in developed nations whereas chronic power shortages in developing nations with increased duration of load shedding and poor quality of electricity. It is mentioned that the reserves margins were shrinking, transmissions lines were becoming overloaded and reliability challenges were greater than at any other time in recent history which has resulted in unprecedented series of rolling blackouts, power alerts and price spikes from North America to Europe (12). From review of major reliability events of the last four years has shown that the major causes to these problems is the requirement to serve the high loads and not due to inadequate generation capacity across a utility system or power pool. Demand-side resources can enhance reliability by moderating those challenging high loads that can affect reliability at all points of generation-transmissiondistribution system (11). In addition to these price spikes and market power in a deregulated electricity market is also contributing in reliability related problems. Electricity cannot be easily stored and therefore must be produced and consumed at the same time but on other hand the system loads vary substantially from hour to hour and the production cost of electricity differ substantially from generator to generator. When there is sudden increase in demand, the utility needs to pay more for operation of generators to maintain the reliability. This results in increase in the price of electricity in spot market. Because of the peculiar nature of electric energy, generators enjoy a power in electricity market. This power is even more if the margin between generation and load is thin as utilities will pay more in order to avoid brownouts, blackouts, and diminished power quality. In these circumstances demand-side resources proves to be the only means to achieve reliability. Beside this the following points justify the need to use demand side resources to obtain reliability (13, 14). •

The cost and time of new generation is very expensive and long.

•

The increasing demand stresses the transmission networks and with the addition of generating plants, the networks should be upgraded. The distance of transferring the energy is becoming long with the deregulated market and the capital requirement is more.

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•

The distribution networks are also overloaded with aging transformers, feeders and substations. Upgrading these networks to reliably support increased load will incur high costs. Historically, more than 90% of all customer outages are caused by distribution-level problems.

•

The depleting layers of fossil fuels and the increase in price of fuels along with instability and conflicts in various reasons increases price of electricity and uncertainty.

•

With the growing environmental awareness among the people, the environmental costs of adding new generation and transmission/ distribution networks have increased significantly. And along with this the inability to operate the units in the needy times due to opposition from public are also seen.

•

Lastly, focusing on supply side resources will never end the problem completely because of existence of weakest links in the system

Energy efficiency and load management programs are proven, cost-effective means of managing load and enhancing reliability by matching electricity demand with the system's generation, transmission, and distribution capacity constraints. Energy efficiency has been widely recognized as the most cost effective way to increase the reliability, safety, and security of our energy infrastructure. Lowering demand is the cheapest way to avoid congestion problems, maintain stable prices, and minimize the environmental impacts of our energy use. Developed countries are investing in policies and programs to realize the energy, economic, and environmental benefits of energy efficiency (12). Demand-side reservoir is large and useful and provides benefits as follows (15). •

It lighten the load at the end of supply/delivery chain, and thus simultaneously enhance the reliability of each link in the entire network, from generation adequacy and fuel supply all the way through to the local distribution network.

•

Energy efficiency load reductions follow the load profile of the end-uses that set the system load curve during critical hours.

•

Enhancing reliability through demand side measures can also lower nation’s electric bills. Many efficiency measures are simply less expensive than the costs of generation, delivery and reserves that they displace. It also widens the margin between demand and supply thus decreasing the price spikes and generator market power.

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•

Load management and load response program lessen the need for new generation, transmission lines, while efficiency measures lower total fuel consumption and related air pollution, fuel extraction, and waste disposal. By lowering the risks of future environmental problems, demand-side measures also improve the long term reliability of the electric system.

Integrated Nepal Power System (INPS) Reliability is virtually taken for granted in most developed countries; this is not the case in developing countries where many basic development projects compete for the available scarce resources. Many electric power projects are cancelled or postponed owing to a lack of resources, environmental problems and other social concerns (22). Present Situation With the total installed capacity of 617.478 MW and peak power demand of 648.39 MW, Nepal has been facing a chronic shortage of supply of electricity. The load factor of INPS is 91% and the plant factor is 44.21%. The demand has seen a growth of 8.60% than the previous year reaching 3,134 GWh in fiscal year (FY) 2006/07. Of which Nepal Electricity Authority has managed to serve 3,051.82 GWh through various sources even though NEA was able to increase its own generation by 11.12% compared to previous year (16). Power Purchase from private producers was 962.26 GWh and import from India amounted to 328.83 GWh. The import increased by nearly 24% in FY 2006/07. Similarly, peak power demand recorded in FY 2006/07 was 648.39 MW, which is an increase of 7.48% compared to that of the previous year. On the other hand the generation capacity only increased by 4.43 MW through 2 Independent Power Producers (IPP) projects in FY 2006/07(16). The obvious result is load shedding during peak hours which increased up to 40 hours a week. Customer Mix An increase of 11.10% than the previous year was seen in the energy sales. Domestic customers with a share of 96% of total customers accounted for 40.37% of total sales. Industrial and Commercial categories representing 2.19% of the total customers accounted for 45.22% of total sales. The number of NEA's customers reached 1.39 million, which is an increase of 8.97% over the previous year. The system losses were reduced to 24.94% in FY 2006/07 against actual losses of 25.12% in the previous year. The main end use in domestic sector is lightening and cooking which is major contributor in peaks. The contribution of each sector can be illustrated from table below.

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User Group Domestic Non-Commercial Commercial Industrial Others

No. of consumer (% of total consumers) 95.92 0.74 0.44 1.77 1.13

Sales %

Revenue (%)

40.20 4.50 6.13 39.23 9.94

40.30 6.25 8.33 36.33 8.79

Table 1: Contribution in energy sales by category Source: NEA Annual Report 2006/07

Constrained Transmission network INPS has major load centers at central and eastern Nepal, whereas, the generating stations are located mainly in western and central region. The present network shows that there is a weak link from Hetauda to Bardaghat. The connection of Hetauda to Bardaghat is at 132 kV single circuit transmission line with PANTHER conductor (16). A fault in either Marsyhayngdi-Siuchatar or in Bharatpur-Hetauda Transmission Line section will overload HetaudaBardaghat Transmission Line resulting into the collapse of the entire INPS system. With the ongoing developments and planned developments, the existing HetaudaBardaghat transmission line will be further overloaded if the generation capacity is increased to meet the unconstrained/normal system load. With the introduction of Middle Marsyangdi HEP into the system, the situation will be even more severe. Hence, up gradation of transmission capacity between Hetauda and Bardaghat has been a task of priority for NEA in order to increase reliability of the system. East west 132 kV transmission line was completed which is the backbone of entire transmission system with the length of 2076 ckt-km. The INPS system has 33 grid substations with a total capacity of 690 MVA. Because of the overloaded transmission system and aged substation transformers, the system has seen more collapse than in previous years. Unique Generating Mix The main generating source of INPS is hydropower and most of the generating plants are medium sized, run of river scheme with or without peaking pondage and storage type. Hence they are unable to be operated when the energy requirement is high in winter during peak demand. Among the total installed capacity of 611 MW, hydro contributes 91% with 556 MW.The largest power plant is Kaligandaki HEP ‘A’ with 144 MW and the total INPS is very much dependent on it. Beside this the only storage type HEP Kulekhani I and II (MW) are being used to cater the peak demand. Beside the power plants owned by 8

NEA, the power plants constructed and operated by IPP’s with total contribution of 148 MW are also playing a crucial role in catering the growing demand of the country. A total of 5 thermal plants are producing 55 MW which consists of 9% of the installed capacity. The import from India has reached 65 MW at present. In total, the INPS consists of 10 medium sized power plants, 10 small sized power plants and 5 thermal pants owned by NEA and 13 power plants both small and medium owned by various IPP’s. A system with a wide range of unit sizes has a more continuous capacity outage probability table resulting in a smoother risk profile (4). This can be seen in operation of INPS system. Since hydro units can usually respond to changes much more rapidly than conventional thermal units they are very useful as spinning reserve and cheaper to operate (4). Interconnection It is found that the power supply from India was started in 1977 with the aim of supplying power to off-grid load center. At present this is done through 22 exchange links which is basically low voltage with low transfer capacity. The supply is not operated as a firm supply but “as and when available basis” in an isolated mode with no operational basis. The exchange limit is augmented from 50 MW to 150 MW. Since the generation mix of India is fossil fuel dominated with the development of good cross border link will prove beneficial to both countries in increasing the system reliability with increased generation capacity. The development of regional grid will also result reduction in spinning reserve (17). So to achieve actual benefit from the interconnection increase in tie capacity, and a better agreement between the two countries is essential.

System Load Curve of INPS The current situation of INPS can be clearly analyzed from the figure below. It shows that the peal power demand is 648.478 MW whereas the installed capacity of INPS is only 617.478 MW. Hence the demand exceeds the supply during the peak hours 1600 to 2100 in the winter seasons (16). With the outage of big power plants like Kaligandaki ‘A’ or Kulekhani I and II, will widen the gap between supply and demand and the system can face a grave situation or lengthy load shedding or total system shutdown in large areas. Nepal does not have any reserves for fossil fuels and the running costs to operate diesel plants is very expensive and with the current tariff scheme the selling price of electricity is very less compared to the generating cost of electricity from diesel plants.

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Following the load shedding, Nepal has seen lots of investment from the private sector in individual level by industries, corporate houses etc in procurement of back up energy sources such as UPS and diesel generators. Beside this lots of isolated generating plants such as solar and micro-hydro are also growing rapidly which is likely to change the composition of INPS in the upcoming years.

Figure:1. Source: Annual Report 2006/07, Nepal Electricity Authority.

Present Policy and exploiting the Demand Side Resources Construction and addition of new generating stations and upgrade of existing transmission and distribution networks has been the top most priority of NEA which require huge capital investment and time span. And with the current instability in the country the flow of investment does not seem easy. And it is for sure that NEA is also following the “turbine and wire” principle in order to enhance the reliability of the INPS by overlooking the third face of solution i.e. demand management. The particular pattern of load curve and the composition of consumers with major portion of it being a domestic type, load management and efficient energy programs can be implemented to bring changes in the load curve and hence change in the relation between supply and demand. It is known that 68 % of the total energy is used for lightening and a simple demand side

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management tools such as replacement of incandescent lamp with of CFL can bring a major change in the situation. A study shows that 250 MW of electric power can be saved with DSM options and 45 MW in Kathmandu itself (18). So in case of INPS, exploitation of demandside resources will prove beneficial along with the investment in generation and transmission, distribution networks. And in the present situation it is the only possible option to control the increase in demand with no new generation plants in the scenario and to contain the gap between demand and supply. Many surveys showed that demand management options can effectively achieve load reductions on electricity networks. These load reductions can be targeted to occur: • across the whole of the electrical load curve, or only at the time of the network system peak; and • generally across the network in a particular geographical area, or restricted to one or more specific network elements such as certain lines or substations. If the load reductions achieved through demand management are sufficiently large and appropriately targeted they may relieve network constraints and consequently may be able to defer requirements to build network augmentations. All types of demand management activities can be used to relieve network constraints. However, whether a particular demand management activity is appropriate and/or cost effective in a particular situation will depend on the specific nature of the network problem being addressed and the availability and relative costs of demand-side resources in that situation (19). In case of Nepal, a network driven DSM is appropriate which focuses on reducing demand on electricity network in specific ways which maintain system reliability in the immediate term and over the longer term defer the need for network augmentations.

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Conclusion The main challenge of today’s power system engineer is to maintain the reliability of power system network in a most cost effective way. With the emergence of internet and digital economy, the society is heavily dependent on the availability of electricity for operations. Inability to provide reliable and quality electricity will result in heavy losses both in terms of productivity and financially. With the changing electric market structure and the behavior of consumers the demand has increased drastically where as the generating of electricity has been constrained by the increase in price of fossil fuels, security and other environmental issues. So with the growing network, the consumers have seen more blackouts, brownouts and poor reliable system. This has been seen as a result of focus on only the supply side resources to address the problem of reliability. The approach of increasing reliability through “turbine and wire “policy has proved little beneficiary. Hence the utilities and governments have begun seeing the importance of demand-side reservoir as a more viable option in present context. With implementation of demand side resources as Energy Efficiency, Conservation, Load Management, Fuel Switching and Distributed energy many countries are able to achieve significant improvements in reliability. This also reduces the economic and environmental costs of electric services. In the situation of Nepal, there is no other viable option besides exploiting the demand side reservoir in other to respond to the increasing demand of the country with no new generating plants in hand. With effective load management the load on the electric grid can be lessened decreasing the margin between supply and demand by lowering cost and enhancing reliability. Overall for reliable grid management a balance should be maintained between supply-side and demand-side investments. The exploitation of demand-side resources is possible only if it is acknowledged by decisions makers and should be reflected in public policies with continuing investments. Long term energy efficiency and short term responses should be considered as complimentary resources. Hence for a country like ours, with excessive demand than supply, dominance of domestic consumers and lightening as end use and with present generation mix demand side management is the only way out to increase system reliability.

References 1. Machowski, Jan. Bialek, Janusz W. and Bumby, James R., Power System Dynamics and Stability, John Wiley & Sons Ltd. 1998. ISBN 0 471 97174X. (PPC). 2. Billinton, R. and Allan, R. N., Reliability Evaluation of Engineering Systems, Concepts and Techniques, Longmans London (England). Plenum Press, New York, 1992. 3. Billinton, R. and Allan, R. N., “Power System Reliability in Perspective”, IEE Electronics and Power, March 1984, pp. 231-236. 4. Billinton, R and Allan, R. N., Reliability Evaluation of Power Systems, Longmans London (England). Plenum Press, New York, 1996. 5. Bazovsky, I., Reliability Theory and Practice, Prentice Hall, eaglewood Cliffs, New Jersey, 1961. 6. Endrenyi, J., Reliability Modeling in Electric Power Systems, John Wiley & Sons Ltd. 1998. 7. Billinton, R., “Criteria Used by Canadian Utilities in the Planning and Operations of Generating capacity”, IEEE Transactions on Power Apparatus and Systems, Vol 3, No. 4, November 1988, pp. 1488-1493. 8. Billinton, R. and Allan, R. N., Reliability Assessment of Large electric Power Systems, Kluwer Academic Publishers, Boston, USA, 1988. 9. IEEE Committee Report, “Bibliography on the Application of Probability Methods in Power System Reliability Evaluation”, IEEE Transactions on Power Apparatus and Systems, Vol. 91, MarchApril 1972, pp. 649-660. 10. Allan, R. N. and Billinton, R., “Power System Reliability and its Assessment, Part 3, Distribution Systems and Economic Considerations”, IEE Power engineering Journal, August 1993. 11. Cowart, Richard., “Efficient reliability: The Critical Role of Demand Side Resources in Power Systems and Markets”, National Association of Regulatory Utility Commissioners. June 2001. 12. Raynolds, Ned. And Cowart, Richard., “The Contribution of energy Efficiency to the Reliability of the U.S. Electric System”, Alliance to Save Energy. USA. April 2007 13. Dutzik, Tony. And Sargent, Rob., “After the Blackout: Achieving a Cleaner, More Reliable Electric System”, National Association of State Pirgs. www.pirg.org . September 2003. 14. Sedano, Richard., “Economic and Reliability Advantages of Energy Efficiency”. ppt. slides. Alliance to Save Energy”. http://www.raponline.org November 5, 2003. 15. Fraser and Company., “The Role of Demand Side Resources in Energy Markets”, Canadian Energy Efficiency Alliance, June 2003.

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16. Nepal Electricity Authority (NEA). “Annual Report Fiscal Year (FY) 2006/07”,. NEA. Kathmandu. Nepal. August 2007. 17. Karki, Arjun B., “Opening Nepal Hydropower Investment and Accessing Indian Electricity Market”. 18. Himal Publication., “Article on Energy Saving”, Year 17, Volume 04, Issue no 196, 16-31 Jestha 2064. 19. NSW Department of Infrastructure, Planning and Natural Resources, Energy Australia and Transgrid., “Demand Management Activities applicable to Electricity Networks”, February 2004. 20. Kushler, Martin., “Energy Efficiency Principles and Conclusions derived from U.S. Experience”. American Council for an EnergyEfficient Economy. October 2003. 21. Adzanu, Steve Kwaku., “Reliability Assessment of Non-Utility Generation and Demand-Side Management in Composite Power Systems”, University of Saskatchewan, Saskatoon. Canada. Fall 1998. 22. Hung, Oliver K. and Gough, William A., “Elements of Power Systems Risk Analysis and Reliability Study”, IEEE Paper. 23. Billinton, R. and Pandey, M. ,”Generating capacity planning criteria determination for developing countries: A case study of Nepal”, Power System Research Group, Saskatchewan University, Saskatoon, Canada; IEE Proceedings, Volume: 146, Issue:5, pp. 491-495. ISSN: 1350-2360. Sep 1999. 24. Billinton, R. and Pandey, M., “Reliability worth assessment in a developing country-residential survey results”, Power System Research Group, Saskatchewan University, Saskatoon, Canada; IEE Proceedings, Volume: 14, Issue:4, pp. 1226-1231. ISSN: 08858950. Nov 1999. 25. Billinton, R. and Pandey, M., “Electric power system reliability criteria determination in a developing country-an investigation in Nepal”’ Energy Conversion, IEEE Transaction. Volume 15, Issue 3, pp. 342 – 347, Sep 2000. 26. Billinton, R., Aboreshaid, S., Fotuhi-Firuzabad, M. and Pandey, M., “Application of reliability concepts to the Nepal Power System’, Power System Research Group, Saskatchewan University, Saskatoon, Canada. IEE Proceedings of EMPD '95., Volume: 1, On page(s): 159-165 vol.1. 1995 Nov 1995.

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Appendix Technical Details of INPS: Major Hydro Power Existing Trishuli

kW 24000

Sunkoshi

Thermal

Private Sector (IPP) kW

10050

Existing Grid connected Birtnagar

1028

Gandak Kulekhani No.1 Devighat

15000 60000

Hetauda Marsyangdi

12750 2250

14100

26000

Kulekhani No.2 Marsyangdi

32000

Duhabi Multifuel-1 Duhabi Multifuel-2 TOTAL

Puwa Khola

6200

Modi Khola

14800

Kali Gandaki ‘A’ Total

144000

69000

13000 55028

Small power plants 10 plants

12792 kW

389150

Solar Simikot

50 kW

Gamgadhi TOTAL

50 kW 100 kW

Transmission Line Length 132 kV 66kv 66kv Underground 33kv single circuit

Existing Andhi Khola (BPC) Jhimruk (BPC) Khimti (HPL) Bhote Koshi (BKPC) Sange Khola (SHP) Indrawati (NHPC) Chilime (CPC) Piluwa Khola (AVHP) Chakukhola (APCo) Sunkoshi Small (SHP) Rairang (RHPO) Khudi Khola (KHP) Baramchi (UHC) Total

Substation Capacity

2076 ckt km 586 ckt km 7 ckt km

132/11 kV 132/33 kV 132/66 kV

71 MVA 358 MVA 211 MVA

2485 km

66/11 kV

424 MVA

66/33 kV 25 MVA TOTAL 1089 MVA Table 2. Source: NEA Annual Year 2006/07

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kW 5100 12000 60000 36000 183 7500 20000 3000 1500 2500 500 3450 980 152713