Unit 3

YO

OLEUM &

n ~;

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

FP

k~ e k ; k ‘ kf D r o’

UNIT 3

SCADA and GIS

Unit 3 SCADA and GIS

73 Notes __________________ __________________ __________________ __________________ __________________

Objectives

__________________

After studying this unit you should be able to:

__________________

y

__________________

Get an overview of the development of IT in power systems and it’s importance in power system operations

__________________ __________________

Introduction The rapid development of information technology (IT) is pushing the power system information network to a remarkable innovation state. Internet/Intranet will play an important role in power system information network. This section reviews the current Internet applications in power systems in areas such as remote information access, Geographic Information Systems (GIS), SCADA/EMS, condition monitoring and predictive maintenance, customers service, power market, power quality, and distance education / training. Though the application of Internet has been developed in many areas, scattered and individual applications hampered the large-scale integration of power system information source. Some preliminary thoughts on a future Internet Based Power System Information Network (PSIN) Architecture will be presented. The section will try to draw a blueprint for future PSIN infrastructure development. Information Technology plays an increasingly important role in creating a competitive edge in the power industry. In the deregulated environment, information becomes the key to profitability, customer retention, market advantage, and growth. The operational and commercial needs of the power industry require information systems not only to perform many traditional operational functions but also support many

YO UNIV ERSIT

__________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

u

fo

n ~;

EN ST U DI ES

__________________

OLEUM &

GY

Notes

Power Transmission

E TR

ER

74

FP

k~ e k ; k ‘ kf D r o’

new functionalities specifically to meet the needs of competition with the deregulated market. Traditionally, information exchanged in a power system is mostly among individual sections of the same utility. Exchange among different utilities is difficult, complex, costly, and backward. Deregulation is pushing for extensive inter- and intra-utility information exchange, integration, consolidation, dissemination, and open access. Existing information management systems could not satisfy the new challenge as the demand for more and faster information increase by many players as shown in Figure 3.1.

Figure 3.1: Information needs in the deregulated environment

On the financial side, deregulation introduces the need for data sharing among different utilities, independent system operators (ISO), metering firms, billing firms, independent power producers (IPP), and Regional Transmission Organization (RTO). As an example, the IPPs, ISOs and RTOs now all require to share the SCADA data to a different degree. Rapid development of information technology (IT) enables information integration and easy access, and provides more effective information management modes for the power industry. Information in the form of data warehouse, distributed database, AM/FM/GIS, OASIS, etc., are being used to replace the traditional information management system from device level to enterprise level.

YO

OLEUM &

n ~;

k~ e k ; k ‘ kf D r o’

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

FP

UNIT 3

SCADA and GIS

Open information architecture is the norm of the future. Traditional power communication system is established mainly for intra-company information exchange. Low bandwidth and communication isolation hinders large information exchange and inter-operation. Deregulation results in horizontal merger and consolidation of many existing utilities. Inter-company communication and integration of data from various control centers, power plants, and substations, is required. The possibility and inevitability to perform this integration process will drive all utilities toward the standardization of data models and communication protocols. Existing communication tools must be modified or replaced to accommodate extensive information exchange. Internet based communication network enables information sharing and various network applications and provide an ideal infrastructure for the next generation of power communication network. Various Internet/Intranet applications are replacing, upgrading, and extending the existing power communication establishment. Open access same-time information system (OASIS) is a good example. While many IT and Internet applications in power systems have been developed in the recent years, most efforts focus on specific tasks, and no universal standard is presented. Isolation among applications hinders the development of power system information infrastructure. For example, OASIS is only used for power transmission transactions, AM/ FM/GIS is mostly used for single utility information management, and Internet applications in SCADA and EMS are limited to remote display and local control. Lack of standards results in waste of resources. The power industry of the future will require an overall information architecture, integrated data model and standard communication network that support the different data requirements, rates and qualities of data flow among the various systems. This section is organized as follows: Section II briefly summarizes the existing information transmission media. Section III reviews the current Internet applications. Section IV will propose a future Internet based information framework for the power industry.

75 Notes __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

YO UNIV ERSIT

__________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

u

fo

n ~;

EN ST U DI ES

__________________

OLEUM &

GY

Notes

Power Transmission

E TR

ER

76

FP

k~ e k ; k ‘ kf D r o’

Brief Review of the Existing Information Transmission Media The power system is using several media for its protection, control, and information-sharing functions. The most common ones include: Power line carrier (PLC), microwave, Fiber optic, Pilot wire and Wireless. PLC operates by transmitting radio band of frequency signals between 10 kHz to 490 kHz over the transmission lines. PLC with power output of order 150 W can be used up to 150 miles. Normally, PLC carries only one channel of 4 kHz bandwidth. The frequency range is limited by government regulations. The PLC is the most common communication media used in the USA for protection. However, it has some disadvantage such as the bandwidth limit. It is subject to lightning, switching surges, and networks reconfiguration. Microwave operates in the 150 MHz to 20 GHz frequency range. This bandwidth can carry a lot of communication channels for a variety of information. The disadvantage of the microwave is that the transmission length is limited to a line of sight path between antennas. Microwave is subject to atmospheric attenuation and distortion. The combined latency using modem plus analog microwave is around 100 milliseconds between two adjacent antennas. Fiber is now considered the most reliable media of communication. Single fiber cable can carry up to 8000 channels. In addition to the capacity the fiber has no interference with other electric systems. The only disadvantage is the cost of the cable and cost of the construction. Fiber optic communication has the smallest latency in all media of the communication. Pilot wire is normally telephone wire either owned by utility companies or leased from telephone companies. This type of communication has a bandwidth from 0 - 4 kHz. Overhead lines may experience interference from power lines while the underground is subject to damages for many obvious reasons.

YO

OLEUM &

n ~;

k~ e k ; k ‘ kf D r o’

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

FP

UNIT 3

SCADA and GIS

Wireless is one of the modern methods of communication. Low orbit satellite communication system provides an exciting option to transmit information covering a very large range. The delay is a problem, which depends on the distance. For example, the latency for low orbit satellite at 10 km above earth is about 300 ms one way. Another disadvantage is the cost of installation. All of the above media may be using different communication networks such as circuit-switched networks, packet-switched networks, and cell-switched networks.

Internet / IT Applications in Power Internet and IT have been involved in many aspects of the power industry as shown in Table 1. In the following paragraphs, some of these areas will be discussed in more detail. n

Utility information management: Geographic information system with automated mapping and facilities management (AM/FM/GIS) and data warehousing are good examples for managing the power system information. Other examples include using AM/ FM/GIS techniques for intra-utility business management that covering finance, human resources, network analysis, outage and distribution management.

n

Operation of power systems: Deregulation has increased the needs of Internet in many areas of power system engineering. Take the interface to the SCADA database as an example. Due to deregulation, such SCADA data is requested by many different segments of the industry such as independent power producers (IPP), transmission and distribution companies, and power trading and exchange companies. As an ideal result of the deregulation, the structure of the power system is changing from the hierarchical structure to a more distributed and open system structure. As a result, many users such as control room dispatchers, operating and planning staff, control center managers, training staff, and engineering users need access to SCADA data. Since Internet can provide remote and open access data

77 Notes __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

YO

u

fo

n ~;

EN ST U DI ES

UNIV ERSIT

OLEUM &

GY

Notes

E TR

ER

Power Transmission

78

FP

k~ e k ; k ‘ kf D r o’

possibility, Web based SCADA display system, flexible EMS and MIS architectures were designed. Real time operational data could be distributed utilizing existing public communication infrastructure. For localized functions, Intranet enables substation, plant, and distribution automation. Many functions, such as Telecontrol, integration, automatic and intelligent decisions from device level to enterprise level can be realized through Intranet. Web based network analysis, such as power flow computation, is also being developed.

__________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

Substation automation is the ability of the substation to take automated intelligent decision with minimal user intervention. To satisfy this goal, Intelligent Electronic Devices (IED) are developed. The Internet will play a more important role in accessing the IEDs and connect the islands of data after the IEDs revolution.

__________________

n

Maintenance of Power System: On-line condition monitoring of HV transmission system equipment such as circuit breaker and other important operation parameters are becoming necessary. Remote vision is important in some special situations such as when the substation is located in an island. It will save time and cost by permitting service organizations to work more independent of equipment operators. Internet based diagnosis tools enhance the automation of periodical maintenance activities and optimize monitoring information analysis. Substation diagnostic programs are being developed, which collect and analyze critical substation equipment information such as transformers and circuit breakers. Power quality (PQ) monitoring becomes more important in the deregulated environment. On-line PQ monitoring systems have been in operation at EDF and DranetzBMI via Internet. Anyone can view the timely monitored results via a Web browser. This offers benefits to both the provider and customer as it enables problems to be identified from both sides and corrective actions taken, and improves coordination and communication between

YO

OLEUM &

n ~;

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

FP

UNIT 3

k~ e k ; k ‘ kf D r o’

SCADA and GIS

the utility and its customers in policing power quality problems. Table 3.1: Internet application in power industry

79 Notes __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

n

Power market: On the energy trading side, development of E-business enables execution of the electric power transactions, maintenance of offers, bids, and transaction histories, and access of real time pricing information via Internet. Open access Same-time Information System OASIS is one such example.

n

Education and Training: Distance education and learning is one important application of the Internet as a cost-effective alternative. It facilities self-paced learning with ability for individualized instruction through immediate reinforcement and feedback. It is clear from the quick survey mentioned in this section that the Internet is a wonderful framework for many of power system applications. We can summarize the advantage of the Internet in the following points. u

Multi-point access

u

Zero client software installation

u

Hardware / platform independent

YO UNIV ERSIT

__________________ __________________ __________________ __________________

Familiar web interface (Netscape / Explorer)

u

Multimedia graphics display capable

u

fo

n ~;

EN ST U DI ES

__________________

u

OLEUM &

GY

Notes

E TR

ER

Power Transmission

80

FP

k~ e k ; k ‘ kf D r o’

There are limitations in today's Internet that may be summarized as follows: u

Security and reliability problems

u

Delays due to:

__________________ __________________ __________________

v

Buffer delays during packet assembly

__________________

v

Conflicts on the asynchronous network

v

Re-transmission due to errors

v

Network traffic and routing path

v

7-200 ms as typical delay in TCP/IP in Ethernet.

__________________

A New Framework for Power System Information Network As we understood from the previous sections that Internet/ IT has already found many applications in the power industry. However, all of them focus on specific tasks and no universal standard is developed. This problem could be solved by introducing a new Internet based Power System Information Network Architecture (PSIN). This framework will consist of physical attributes, logical attributes, and tools dealing with these attributes. Physical attribute is about the information location, such as spatial information, connection information, etc. Logical attribute depends on the former, and is about the information functionality, security, timeliness, objective, etc., refer to GIS configuration. Power information can be organized in "layers" (group or themes). Each layer belongs to a specific topological type and relating to a specific type of data. It is convenient to have the PSIN architecture divided into physical layers and logical layers as described in Figure 3.2. In the basic PSIN architecture (Figure 3.2), data and information that may be scattered throughout the organization in different divisions and categories is integrated in a generic manner.

YO

OLEUM &

n ~;

k~ e k ; k ‘ kf D r o’

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

FP

UNIT 3

SCADA and GIS

81 Notes __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

Figure 3.2: Basic architecture of the power system information network

Physical layers relate the physical location information, and can be divided into many sub-layers according to the physical attribute. Areas controlled by one ISO can be one physical sub-layer, which also consists of different voltage-level transmission line layers, power plant layers, substation layers, and control center layers. All the physical layers will contain information at different detail level. As an example, the regional layer will contain some information about the power plants but if one needs a complete picture about the power plants one will have to go downstream to power plants information levels. As a general navigating rule in the physical layer, when going downstream in the physical layers, one will get information in greater detail. On the other hand, when going upstream, general picture of the power system will be given. These physical layers will be used as a search guide in PSIN. Logical layers are divided according to information functionality. With the detailed information functions, logical layers will extend to more sub-layers in either horizontal or vertical directions. Logical layers depend

YO UNIV ERSIT

__________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

u

fo

n ~;

EN ST U DI ES

__________________

OLEUM &

GY

Notes

Power Transmission

E TR

ER

82

FP

k~ e k ; k ‘ kf D r o’

on physical layers. Different physical layers may have different logical layers but, generally, all these logical layers have similar structure. On the multi-regional HV power grid map, power market layers for inter-ISO transactions are shown, but information about the distribution and customer layers are not needed. For the same logical layer, information contents are also different for different physical layers or same physical layers in different areas. Flexibility, inheritance (a parent-child relationship between one layer and its sub-layers), and encapsulation between layers are used for the PSIN architecture.

__________________

Figure 3.3: Categories of information manipulation / Tools

Another important part of this infrastructure deals with tools required for data manipulation. Data manipulation can be realized between layers and within the same layer. As shown in Figure 3.3, data manipulation depends on information functionality and its layer location in the PSIN architecture, and can be divided into different classes. SCADA/EMS/DSS and DMS can be considered as certain types of information manipulation. Load flow analysis is another example of data manipulation. As stated earlier, based on object-oriented techniques, information

YO

OLEUM &

n ~;

k~ e k ; k ‘ kf D r o’

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

FP

UNIT 3

SCADA and GIS

manipulation should have the following features: encapsulation, inheritance, and polymorphism. Encapsulation means that most data manipulation should be combined with related data into a single entity, for example, SCADA and its related database should be encapsulated together into one object. Inheritance is cloning one module after another. It defines that the manipulations in upper layers may have the same behaviors with its sublayers and additional functions. For example, SCADA operation in utility physical layers can manipulate the plant data besides the substation data in substation layers, but SCADA in substation layers can only manipulate the substation data. Polymorphism means the same operation may have different functions for different layers or different data. Monitoring at system operation level may mean the detection of variables such as power frequency, voltage, current, active and reactive power, and different set of variables in equipment maintenance, such as temperature, pressure, transients, etc. Many components or methods will be integrated using objectoriented techniques. Combining the information manipulation and the information management parts together, the entire PSIN architecture is basically formed. This new infrastructure will offer many functions. To list a few, it should include: n

Geographic queries and analysis.

n

Complete picture of the power network.

n

Improved information management and integration among ISOs or RTOs.

n

Reduced data redundancy.

n

Standard way of communication among different entities.

n

Improved power flow, system security, and congestion management.

It is important to point out that PSIN is only a framework and it attempts to provide a standard architecture in many

83 Notes __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

YO UNIV ERSIT

__________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

u

fo

n ~;

EN ST U DI ES

__________________

OLEUM &

GY

Notes

Power Transmission

E TR

ER

84

FP

k~ e k ; k ‘ kf D r o’

aspects. However, access authorities for different types of information will remain the power of the information owners. [Thoughts on Future Internet Based Power System Information Network Architecture, A.R Khatib, X Dong, B Qiu, Y. Liu, Virginia Tech, Blacksburg, VA, USA]

Supervisory Control & Data Acquisition System (SCADA) SCADA focuses on gathering and circulating the right amount of system information to the right person or computer within the right amount of time so that creative solutions are made possible. The blackout occurring worldwide, including the August 14, 2003 blackout in the United States demonstrates the importance of a properly functioning SCADA System in preventing future blackout. Knowledge of electric utility power system monitoring and control is critical to operating and managing the power system in normal conditions and especially in abnormal circumstances such as with extremely bad weather conditions or with a series of cascade outages in the power system. Both academia and industry must do a better job to educate student and industry in SCADA fundamentals and applications. In India, what ails the Industrial Automation sector is the shortage of appropriately trained engineers for specialized jobs in automation. Therefore, there is a need for significant rise in the level of automation, as more and more process industries like steel, cement, food processing, petrochemicals, refineries, electronic industries, etc. are getting automated. In power systems also, SCADA has widespread application in generation, transmission, distribution and substation automation. Thus a large amount of data needs to be acquired, processed, and presented to the operator and the system engineer for effective operation of the power grid. These functions can be handled very effectively using a distributed processing system. The system engineer can also readily install new hardware for on-line data acquisition and control.

YO

OLEUM &

n ~;

k~ e k ; k ‘ kf D r o’

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

FP

UNIT 3

SCADA and GIS

The significance of the laboratory is highlighted by the developments in substation automation and supervisory systems which are revolutionizing the automation scenario in power systems. 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 Control System used in real time power systems and industrial establishments which supports a global data base. The use of such a system was favored against that of personal computers with data acquisition add-on cards, in order to acquaint students with the standard industrial practices. The complete engineering and SCADA development is through single software running on Windows. The software has unlimited tags, trends, graphical displays and has a built in sequence of events (SOE) recording, which is very essential for fault diagnosis. The software also has the Dynamic Data Exchange (DDE) module, which enables it to import and export data with other application software. The SCADA Software will be linked with ETAP (Electrical Transients Analyzer Program) and MATLAB etc. so that the system is more versatile. Modern SCADA Systems employ a computerized SCADA Master in which the remote information is either displayed on an operator's computer terminal or made available to a large energy management system (EMS) through networked connections. The substation RTU is either hardwired to digital, analog, and control points, or it frequently acts as a sub-master or data concentrator in which connections to intelligent devices inside the substation are made using communication links. Most interfaces in these systems are proprietary, although in recent years standard-based communication protocols to the RTUs have become popular. The SCADA/EMS laboratory has been set up with the view of providing students and practicing engineers with hands on learning experience on SCADA system and its application 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 industry are the propriety items for each company

85 Notes __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

YO UNIV ERSIT

__________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

u

fo

n ~;

EN ST U DI ES

__________________

OLEUM &

GY

Notes

E TR

ER

Power Transmission

86

FP

k~ e k ; k ‘ kf D r o’

and hence very few technical details are available for the 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.

Benefits Present Benefits The power needs have grown and the demands for reliable and accurate performance and trend data have increased. High Volt Technicians need to be able to remotely and instantaneously, identify electrical power loop feeder sections that are affected, and respond accordingly. When a particular section of the distribution system goes down, the operators are provided with instant information. This enables the system operators to provide individual building managers, researchers, department chairs and others, information on the problem. In addition, the engineers are able to examine historical data for load trending, planning and improving system performance. In addition, the following functions are being utilized more and more as the SCADA system is expanded across campus. n

Manual meter reading is being replaced with automatic reporting.

n

Real time alarms and data give operators the information they need to respond quickly.

n

The Utilities Division can be proactive in providing quality information to its customers.

Long Term Benefits and Future Needs Power System Operators need to be able to continue to remotely and instantaneously, identify electrical power system failures at any location in the distribution system. Accurate real time alarming and historical information is needed to continually meet the needs of a diverse community of energy users. A continuation of the demands for high reliability and accurate performance and trending data is paramount.

YO

OLEUM &

n ~;

k~ e k ; k ‘ kf D r o’

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

FP

UNIT 3

SCADA and GIS

For example, Stanford has already been experimenting with the web based metering and plans to incorporate, and design custom features with off the shelf web based tools. This will allow users within the university community to access specific information by using a web browser instead of expensive third party software (e.g., energy consumption report, performance data, etc.).

Role of GIS as a Decision Support System in Power Transmission

87 Notes __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

Introduction Operational & Maintenance requirements of Utility lines sector require a multitude of data elements. For instance, tremendous amount of data is required to maintain the ribbon-like corridors that Transmission lines weave through the landscape. Property ownership data element is of particular importance to right-of-way (ROW) maintenance. Powerline characteristics are another collection of data elements that describes the physical characteristics of the line, its current condition, and that which is being transported through it. The physical characteristics of the lines are determined during construction & forms dynamic data elements which is required for engineering planning & other analysis. The data elements (Land-use/land-cover, ownership and powerline characteristics etc.,) which has both static and dynamic components pose a formidable challenge for proper maintenance and operations in a utility sector. Key factor of efficiency in the work flow is automation of technological processes applied to data gathering, integration and processing, production of complete topographic products and their customized presentation, analysis and interpretation. The automation can be achieved by employment of: n

Complete set of modern data gathering remote sensing devices such as airborne laser locators, digital aerial photo cameras, thermo vision devices with digital output equipped with GPS and inertial navigation system.

__________________

YO UNIV ERSIT

__________________ __________________ __________________ __________________ __________________

u

fo

n ~;

EN ST U DI ES

n

OLEUM &

GY

Notes

E TR

ER

Power Transmission

88

FP

k~ e k ; k ‘ kf D r o’

Proprietary software for integration and processing data collected by the airborne remote sensing devices and for presenting complete information product in a format compatible with common CAD and GIS applications as well as customized applications required by the operation managers of the utility sector.

__________________

This chapter will outline the utility of Remote Sensing & GIS technology in a case of transmission line utility sector for

__________________

1.

High speed data acquisition of transmission line networks.

2.

Photogrammetric processing in integrating the airborne acquired data with a GIS system.

3.

Maintain the critical facility database.

4.

Support of a Desktop GIS system in maintenance and operational requirements as shown in the figure 3.4.

__________________ __________________

__________________

Figure 3.4: The utility of Remote Sensing and GIS Technology

YO

OLEUM &

n ~;

k~ e k ; k ‘ kf D r o’

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

FP

UNIT 3

SCADA and GIS

Utilities Management through Spatial Technology Tools Utilities need detailed information about the location and condition of their transmission corridor assets and right of ways to quickly and efficiently maintain and service them. To accomplish this, utilities need to regularly inspect and collect accurate spatial data of their facilities. Also the data must be wrapped in an enterprise system, which would support planners and managers in all the phases of utilities management. Present day advancements in the spatial technology of Remote Sensing & GIS provides variety of tools in extending support to utilities management. To broadly classify the framework wherein the Remote Sensing technology & its tool of GIS fits into a utility sector can be divided into the following overhead of operations; n

Assets inspections & inventory.

n

For various Spatial Analysis (e.g. distribution planning, mapping, routing to transmission poles, terrain analysis, transmission pole siting etc.) in support of utilities managers.

Utilities sector have employed a combination of techniques to address the first scenario of asset inspection & inventory, which includes ground surveys and aerial photogrammetry. These techniques have the extensibility to provide improved accuracy in location, visual identification of issues regarding rights-of-way, property lines and potential safety hazards, high-resolution digital images for performing detailed inspection, digital information capture for seamless export to a GIS environment, a terrain baseline identification which can be useful for regulatory and legal purposes, and data archival capabilities for temporal analysis. The management and analysis of enormous amount of data generated in a utilities management sector is a daunting task. An enterprise system is needed to address issues such as: n

Inspection & assessment of overhead lines. Routine inspection. Safety code compliance inspections. Facility inventory (poles, structures, towers, pad mounts).

89 Notes __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

YO UNIV ERSIT

u

fo

n ~;

EN ST U DI ES

n

__________________

OLEUM &

GY

Notes

E TR

ER

Power Transmission

90

FP

k~ e k ; k ‘ kf D r o’

Maintenance planning and forecasting. Documentation of component conditions and maintenance needs.

__________________ __________________

n

__________________

Right-of-way management vegetation management and tree trimming. Weed management.

__________________ __________________

n

Facility mapping.

n

Animal-caused outage studies.

n

Migratory bird collision studies.

n

Inspection & assessment of overhead lines.

n

Powerline routing and permitting.

n

Thermal rating studies.

n

Access planning.

n

Emergency response planning.

n

Environmental studies.

__________________ __________________ __________________ __________________

The task highlighted is only the core functional tasks in inventory, Planning and Engineering operations of a utility sector. The spatial components in the functional requirement can be effectively addressed by an integrated GIS system. It is imperative that a flexible framework has to be identified to address the requirements of the multi-faceted utilities industry. The following section highlights a framework of solution for Spatial Data capture using Aerial Photogrammetry and an integrated desktop GIS system in support of typical functional features in a transmission line utility sector.

YO

OLEUM &

n ~;

k~ e k ; k ‘ kf D r o’

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

FP

UNIT 3

SCADA and GIS

A Case Study

91 Notes __________________

Spatial Data Capture Process

__________________

InfoTech's Photogrammetric division, identified the

__________________

framework for processing the data acquired in aerial

__________________

photogrammetry in a format directly integrateable with a

__________________

GIS system.

__________________ __________________

Design of Desk Top GIS System to Support Utility Managers in Maintenance & Operations InfoTech's Geographic Services team worked in identifying crucial requirements in utilities services and developed a pilot architecture in addressing the same. The primary task of the team was in the design of a desktop Transmission Line Reviewing system which would address points such as: n

Spatial data integration acquired from aerial mapping.

n

Inspection & maintenance.

n

Engineering & planning operations.

n

Real Time Routing.

n

Integration with conventional tabular database.

n

Report generation.

n

Vegetation management.

The system flow designed is outlined in Figure 3.5 below. The framework of the architecture consists of Clients, Services, and Management. ArcView GIS (Desk top GIS product of Environmental Systems Research Institute Inc.,) provides the basic high-end geographic information systems (GIS) and mapping services for the GIS functionalities that are required for the application. The entire framework of the desktop system can be customized in a single user interface through the customization environment Avenue, available in ArcView.

__________________ __________________ __________________

YO

u

fo

n ~;

EN ST U DI ES

UNIV ERSIT

OLEUM &

GY

Power Transmission

E TR

ER

92

FP

k~ e k ; k ‘ kf D r o’

Notes __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

Figure 3.5: System flow design

ArcView GIS offers the extensibility to attach additional features to the primary design, such as the extension 3D analyst can be interfaced with the design for terrain analysis, line of sight analysis and other 3 dimensional analysis that might arise in a typical transmission line operations and maintenance. The Network analyst extension support the users in routing analysis such as routing to any transmission line facility with turn-by-turn directions, accurate travel time calculations and distance figures. Image analyst extension for analysis of digital imageries for cases of temporal analysis, vegetation growth study, thermal anomalies detection etc.

YO

OLEUM &

n ~;

k~ e k ; k ‘ kf D r o’

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

FP

UNIT 3

SCADA and GIS

The Sag analysis of power lines can be addressed by integrating ArcView with SagSec (a product of Powerline Systems Inc). This module can support users in calculating the section static equilibrium configuration for arbitrary combinations of:

93 Notes __________________ __________________ __________________ __________________ __________________

1.

sagging conditions,

2.

wind velocity and direction,

3.

balanced or unbalanced ice,

__________________

4.

temperature,

__________________

5.

broken conductors or insulators,

6.

slack redistribution through offsets or other means and

7.

support relocations with a fixed length of cable between the dead ends, etc.

__________________ __________________

__________________

Tabular data integration with ArcView GIS is achieved by ODBC support to custom RDBM's. Report generation feature can be handled by Crystal Report access within ArcView GIS. Optionally, depending upon the operational constraints, the spatial data can be stored in a RDBM's and interfaced with the desktop system via the Spatial Database Engine interface through ArcView. Benefits of the Integrated Desk Top Transmission Line Management Support System The explicit benefits associated with an scalable architecture described above are a point in question as far as any utility sector is concerned. The architecture aptly mixes the best of available "Commercial Off the Shelf" software in addressing the core requirements of a typical transmission line maintenance & operations scenario. The framework reduces the need for long term development of solution in one single vendor application, rather it extends as a "plug-in" kind of environment wherein additional features can be incorporated as and when the need arises. Further advantage offered in the framework is the evolution of the desktop GIS environment ArcView into the latest

YO UNIV ERSIT

__________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

u

fo

n ~;

EN ST U DI ES

__________________

OLEUM &

GY

Notes

E TR

ER

Power Transmission

94

FP

k~ e k ; k ‘ kf D r o’

ArcGIS architecture, which is open for customization in industry standard language and also extensible for support in both desktop and Internet environment.

Conclusion Power is an integral part of any country's infrastructure. Today, more than 100,000 MW of installed capacity powers India. The facilitating policy framework, the regulatory mechanism for investment in generation, transmission, distribution and other associated activities have already been put in place by the government. The need of the hour is for efficient management and optimum utilization of installed capacity to meet the demand. The paper highlighted the salient points of Remote Sensing and GIS technology in addressing the utility sector needs and effectively drew a framework of operation in a typical Transmission Line Utility sector. The utility sector should capitalize on the advancement in the Spatial Technology to envision our government's policy plan of "Power on Tap" by 2012.

Acknowledgement We thank Mr. B.V.R. Mohan Reddy, Managing Director, InfoTech Enterprises Limited, Mr. Rajeev Lal, Chief Operating Officer, Dr.Nagesh, Division General Manager, who have been a constant source of dynamism and inspiration to all of us. We are also thankful to all our associates who are the players behind the screen.

Reference n

Thomas, Helmer, 2001, "ArcGIS 8 Enabling Energy Delivery Resource Planning (EDRP)", ESRI International User Conference.

n

Richard, Vann, 2000, "Populating a GIS of Utility Corridor Assets using an Integrated Airborne Data Acquisition System", ESRI International User Conference.

YO

OLEUM &

n ~;

k~ e k ; k ‘ kf D r o’

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

FP

UNIT 3

SCADA and GIS

GIS application for power transmission line siting: An illustrative case

95 Notes __________________ __________________ __________________

Tyeb Pervaiz

__________________ __________________

GIS Development Analyses such as the selection of suitable areas, the optimum path finding, the profile analyses, the engineering design of towers and wires, and the cost estimation can be done using GIS. In the last few decades, the electric power industries have been developing power transmission systems to follow up with the rapid growth of the power demand. On the other hand, the suitable site for new transmission lines has been getting restricted, because of development of rural areas and the growing concern over environmental issues. Analyses such as the selection of suitable areas, the optimum path finding, the profile analyses, the engineering design of towers and wires, and the cost estimation can be done using GIS. This will help planners and engineers in the environmental and engineering analyses for transmission line siting.

Application System In general, the process of the planning and design of transmission lines consists of the following 5 phases. n

Planning: The master guidelines of route constructions are settled based on the long-range power supply plan. The outline is determined for each transmission line planned, which includes voltage, number of lines, starting and ending substations.

n

Survey: Information about natural environment, geological features, local communities and regulations in the area of interest, etc. is collected in this phase and several alternative routes are compared in terms of environmental impact, technical issues and cost of construction.

__________________ __________________ __________________ __________________ __________________

n ~;

YO UNIV ERSIT

ST U DI ES

u

fo

EN

k~ e k ; k ‘ kf D r o’

n

Basic Route: Basic route is determined by the position of each tower along the proposed routes and interference of radio wave caused by the transmission line is estimated. All this is done using a medium scale toposheet.

n

Detailed Route: A photogrammetric surveying is performed along the basic route. Based on the results, the detailed position of each tower is determined in the large scale (1:2,000). And engineering design process follows, which includes the determination of tower type, tower height and supporting devices, and the cost estimation.

n

Route for Implementation: In this phase, the detailed field surveying is performed along the determined route. The towers, wires and basement of towers are designed.

__________________ __________________ __________________ __________________ __________________

OLEUM &

GY

Notes

E TR

ER

Power Transmission

96

FP

__________________ __________________ __________________ __________________ __________________

The computer system developed here supports phase 1 to 4, and consists of 5 subsystems. Figure 3.6 shows the outline of the system

Figure 3.6: Outline of the System

Each project execution components have been described below: Data Entry System: This system installs, checks and edits the geographical database used in all other subsystems. The

YO

OLEUM &

n ~;

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

FP

k~ e k ; k ‘ kf D r o’

UNIT 3

SCADA and GIS

database includes Topographical Maps in 1:50,000 (raster images), Environmental Information (Coverages), Land Information Database (governmental boundaries, roads, railroads, rivers, lakes (coverages), altitude (GRID), Photogrammetric Maps in 1:2,000 scale (raster images), DTM (GRID), etc. Route Zone Evaluation Supporting System: The purpose of this subsystem is to select the zone, called the "route zone", which is considered suitable for a transmission line in terms of environmental impact and regulations. The route zone is determined in the medium scale of about 1:50,000. The functions of this system are: n

Display and plot environmental database.

n

Create the optimum route.

n

Create suitability map.

n

Create aerial view.

n

Estimate the construction cost.

Basic Route Evaluation Supporting System: The position of each tower is determined interactively referencing the topographical maps, the suitability maps and the optimum route computed above. Figure 3.7 displays the functions of the subsystem.

Figure 3.7: Basic Route Evaluation Supporting System

97 Notes __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

YO UNIV ERSIT

__________________ __________________ __________________ __________________ __________________

EN

u

fo

n ~;

ST U DI ES

__________________

OLEUM &

GY

Notes

Power Transmission

E TR

ER

98

FP

k~ e k ; k ‘ kf D r o’

Detailed Route Evaluation Supporting System: Once the basic route is determined, the photogrammetric surveying is performed along the route to make planimetric, topographic maps, and DTMs in the large scale of 1:2,000. Based on the database, the detailed position of each tower is determined. Furthermore, the system has various functions to perform the engineering analyses. Figure 3.8 shows the functions of this subsystem.

__________________ __________________ __________________ __________________

Figure 3.8: Detailed Route Evaluation Supporting System

Wave Interference Evaluation: Supporting System A transmission line may cause the interference in television and microwave communication. The purpose of this subsystem is to predict the wave interference caused by the determined transmission line. The system has functions as shown in Figure 3.9.

Figure 3.9: Wave Interference Evaluation Supporting System

YO

OLEUM &

n ~;

k~ e k ; k ‘ kf D r o’

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

FP

UNIT 3

SCADA and GIS

Methodologies Suitability Map and Optimum Route: The existing process of the site selection is evaluated and as per the need, the environmental information can be classified into categories like, natural, social and technical environment. Each of these categories contains layers as mentioned below. n

Environment containing habitats of endangered species, national parks, etc

n

Social environment containing view points, scenic areas, cultural assets, temples, shrines, agricultural promotion area, forest area, cities, district for urban planning, airports, etc.

99 Notes __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

n

Technical environment containing faults, dangerous district for collapse, areas of snowfall, thunderstorm, salty breeze, wind pressure, etc.

An index should be introduced to represent the relative difficulty of the route construction, based on the experience of engineers. The index may be defined as: Index = 4 [Negative Control Point (The route must not pass through)] Index = 3 [Route construction is strictly regulated, or has a great impact.] Index = 2 [Route construction may be permitted, or has a moderate influence.] Index = 1 [Route construction has a slight influence.] Index = 0 [No problem for route construction.] The index number can be assigned to each polygon feature of the environmental database, according to the difficulty of route construction. For point or line features, a sort of buffer procedure can be performed using GRID function, and the index number can be assigned according to the distance from the center. The suitability map can be created by overlaying and summing up all indexed layers. This procedure will utilize GRID functions, and is shown in Figure 3.10.

__________________ __________________

YO

OLEUM &

n ~;

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

Power Transmission

100

FP

k~ e k ; k ‘ kf D r o’

Notes __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

Figure 3.10: Create Suitability map and determine optimum Route

The resulting suitability map can be considered to represent a sort of impedance for route construction. Using GRID COST DISTANCE functions, the optimum route can be computed based on the suitability map as shown in Figure 3.10. Determine Tower Height: In the detailed route, height of each tower can be determined to minimize the cost of construction of the whole route. It can be accomplished as shown in Figure 3.11. n

First, the possible combination of tower height should be computed for each span. The required clearance of wire should be ensured over the ground and structures.

n

Then, the combinations of tower height are joined along the whole route. The result is constructed as a network model with a turntable. The cost of each turn is computed, which depends on the tower height and the tower type.

n

Finally, the optimum path can be derived using NETWORK PATH command, based on the cost at each turn. The resulted path corresponds to the most costeffective tower height combination.

YO

OLEUM &

n ~;

k~ e k ; k ‘ kf D r o’

ST U DI ES

u

fo

EN GY

UNIV ERSIT

E TR

ER

FP

UNIT 3

SCADA and GIS

101 Notes __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________

Figure 3.11: Determine Tower Height

Profile along the Detailed Route: Once the detailed route is determined, the profile along the route can be plotted as one of the final results. This plot includes the profile along the route, the structures under wires, the required clearance, the dip of wires, and the towers. Figure 3.12 shows an example of the profile plot. These features are plotted using specific command modules of the GIS software. The curves of structures, clearance and wire dip can be computed.

Figure 3.12: Profile along the Route

YO UNIV ERSIT

__________________ __________________ __________________ __________________

u

fo

n ~;

EN ST U DI ES

__________________

OLEUM &

GY

Notes

E TR

ER

Power Transmission

102

FP

k~ e k ; k ‘ kf D r o’

Estimate the Construction Cost: The cost estimation can be accomplished using a spreadsheet package. The specifications of towers and wires, can be read by the spreadsheet. Further, in-house can be used to create a ledger of the route or to estimate the construction cost.

Conclusion

__________________ __________________ __________________ __________________

Several extensions can be incorporated into the system. The extensions include the automatic siting of each tower, the use of the result of detailed-field surveying and the simulation of realistic views using CAD/GIS packages.

__________________

Reference Masahiko Murata, Systems Engineering Center, PASCO Corporation, TOKYO, JAPAN.