0071490191_ar025.pdf

Source: STANDARD HANDBOOK FOR ELECTRICAL ENGINEERS

SECTION 25

COMPUTER APPLICATIONS

IN THE ELECTRIC POWER

INDUSTRY

Tom Qi Zhang*

Senior Software Consultant, AREVA T&D Corporation

CONTENTS

25.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25-1

25.1.1 Growth of Computer Applications . . . . . . . . . . . . . .25-1

25.1.2 Goals of the Power Industry . . . . . . . . . . . . . . . . . . .25-3

25.1.3 Spectrum of Computer Usage . . . . . . . . . . . . . . . . . .25-5

25.2 ENGINEERING APPLICATIONS . . . . . . . . . . . . . . . . . . . . .25-7

25.2.1 System Expansion . . . . . . . . . . . . . . . . . . . . . . . . . .25-7

25.2.2 System Planning and Analysis . . . . . . . . . . . . . . . . .25-8

25.2.3 Design and Construction . . . . . . . . . . . . . . . . . . . . .25-10

25.2.4 Project Management . . . . . . . . . . . . . . . . . . . . . . . .25-13

25.2.5 Administrative Support . . . . . . . . . . . . . . . . . . . . . .25-13

25.2.6 Power Market Computer Simulation . . . . . . . . . . . .25-14

25.3 OPERATING APPLICATIONS . . . . . . . . . . . . . . . . . . . . . .25-15

25.3.1 Supervisory Control and Data Acquisition System . .25-15

25.3.2 Energy Management System (EMS) . . . . . . . . . . . .25-16

25.3.3 Power Plant Monitoring and Control . . . . . . . . . . . .25-23

25.3.4 Power Plant Maintenance . . . . . . . . . . . . . . . . . . . .25-23

25.3.5 Fuel Management . . . . . . . . . . . . . . . . . . . . . . . . . .25-24

25.3.6 Load Management . . . . . . . . . . . . . . . . . . . . . . . . .25-24

25.3.7 Nuclear Data Center . . . . . . . . . . . . . . . . . . . . . . . .25-24

25.4 ENGINEERING COMPUTING TRENDS . . . . . . . . . . . . . .25-25

BIBLIOGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25-28

25.1 INTRODUCTION

25.1.1 Growth of Computer Applications

The power industry is engaged in the generation, transmission, and distribution of electrical energy

which is obtained by conversion from other forms of energy such as coal, gas, oil, nuclear, water, or

other renewable energy. These activities often include mining, rail transport, shipping, slurry

pipelines, and storage of energy in many forms. Many electric utilities are also engaged in the trans-

mission and distribution of gas.

In the first 90 years of its history, the industry expanded at a pace nearly twice that of the overall

economy, doubling roughly every 10 years. During this period, real prices per kilowatthour

* The author acknowledges the contributions of past authors and reviewers including James V. Mitsche (PTI), M. M. Adibi

(IRD), and J. D. Cypert (IBM).

25-1

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COMPUTER APPLICATIONS IN THE ELECTRIC POWER INDUSTRY

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SECTION TWENTY-FIVE

decreased steadily because of generation, transmission, distribution, technical improvements, pro-

ductivity increases, and stable fuel prices. Throughout the 1970s, increased fuel costs, limits in

economies of scale, diminishing returns in technology improvement, and increased regulation costs

led to increased kilowatthour costs and reduced demand growth.

The political and economic response to increasing costs has been a movement to smaller gener-

ator sizes, minimization of capital investment, and attempts to control costs by fostering competition

in generation supply. Incentives were also established to reduce demands and increase load factors.

Today power supply is diversifying away from large central station technologies and toward

increased use and availability of the transmission system.

In scheduling its day-to-day operation, and in planning for its future growth, the industry has

made extensive use of analytical tools and mathematical models which, through optimization and

simulation, help in the decision-making process. As a consequence, the industry has long been one

of the largest users of computers and among the most sophisticated in its modeling and computa-

tional techniques. This use is quite understandable when one considers the high cost of power sys-

tem equipment, the complexity of power systems, and the severe operational, reliability, and

environmental requirements on the electricity supply.

Computer applications have assisted the industry in achieving its objectives: reducing the cost of

energy delivered to consumers, improving the quality of service, enhancing the quality of the environ-

ment, and extending the life of existing equipment. These objectives have been achieved as follows:

1. Since the industry is one in which capital investment is usually high (over 10% of total spending

by the nation’s industries), unit costs have been reduced by operating facilities closer to their

design limits, allowing better utilization of equipment.

2. Unit costs also have been reduced by automation, allowing operation with fewer personnel, and

by optimization, lowering fuel consumption per kilowatthour delivered.

3. Electricity cannot readily be stored; therefore, production and consumption must be simultane-

ous. Hence enough capacity is required to meet the maximum coincident demand or peak load of

all customers. Interconnections between power systems provide important economies arising

from different time patterns or diversity of use of the component systems in the network. They

allow higher power system reliability at lower capital cost.

4. Quality of service has been improved by reducing the number, extent, and duration of service

interruptions, thus providing a more reliable service.

5. Quality of environment has been maintained by operating facilities within acceptable bounds of

emission, thermal discharge, waste disposal, and more effective land use.

Today the industry has reached a stage where computer systems are no longer merely an engi-

neering tool. The effectiveness of computer applications is one of the key elements in achieving the

basic functions associated with the planning, designing, construction, operation, and maintenance of

the power system. In fact, engineering and computers have been integrated. This integration may be

viewed as tending toward the construction of a utility industry information system. Such a system is

shown in Fig. 25-1. It depicts a typical information system which may be viewed as a combination

and integration of several functional information systems.

Such an information system can extend the company capabilities by making relevant and cur-

rent information accessible to both technical and management personnel. Designs can be refined by

using measured data or operations experience, projects can be monitored, revenue requirements can

be predicted more closely, and the experience of operations can be reflected in the methods and cri-

teria used in planning and engineering. The information system thus can provide meaningful data

at proper times and locations to make decisions and concentrate resources in the most effective

manner.

Computers and their applications are ubiquitous in electric utilities. As in most industries, the

business and corporate uses are extensive. This section deals with the sophisticated engineering and

operations applications of computers, which are often unique and specialized to the industry’s goals

and technical demands.

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FIGURE 25-1 Electric utility information systems.

25.1.2 Goals of the Power Industry

The industry’s purpose is to provide adequate, reliable, environmentally compatible electricity at reason-

able cost with the ultimate goal of improving its productivity and net earnings. In spite of the differences

between publicly and privately owned utilities, this goal is applicable to each, in different form. This

goal is reached by pursuing a number of objectives as described below.

Improved Financial Management

• Raising new capital . Traditional electric utility companies and independent power producers are

major utilizers of capital to finance and build new capacity, replace or renovate old equipment,

and retrofit plants and delivery equipment for environmental and reliability considerations.

Projected industry construction in the next decade runs into hundreds of billions of dollars.

Competing demands for capital and its high cost encourage and justify precise planning, design,

and operations.

• Plant investment . Utilities must spend very large sums in generating plants and transmission facil-

ities. Present-day decisions on such additions, together with the proper selection of plant sites and

the acquisition of transmission rights of way, have long-range financial implications affecting earn-

ings. At present, the industry is experiencing difficulties in selection of plant sites and obtaining

rights of way, licenses, and permits, with the results that the industry seldom obtains new plant

sites and is forced to expand existing generating sites. Demand-side options must be properly

weighed against generation expansion alternatives. Independent power producers (IPPs) must

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SECTION TWENTY-FIVE

make precise investments, and utilities must properly invest in facilities needed to utilize and

accommodate IPPs. This situation compounds the problems of system modeling and system losses,

and increases transmission system dependency.

• Long-term contracts . Fuel constitutes about 35% of the industry’s total annual operating expenditures.

A typical modern power plant consumes about 500 tons of coal each hour, and its average life is about

30 years. A nuclear power plant of a similar size requires an initial nuclear core costing hundreds of

millions of dollars plus a significant annual refueling expenditure for the next 30 years. Independent

power producers supply energy under contract for varied periods and conditions. The goal is to pro-

cure energy supply and these fossil and fissile fuels through long-term contracts providing a con-

tinuous supply of fuel at reasonable cost throughout the plant’s 40- to 60-year life.

• Growth through affiliation . There have been a significant number of corporate mergers between

large and small utilities. The goal in these affiliations is to meet the growth in demand for energy

by taking advantage of economy of scale; consolidation of administration, engineering, construc-

tion, research, and development; and increasing reliability of bulk power supply.

• Economy and reliability . The industry has achieved significant improvement in economy of oper-

ations and in reliability of power systems either through direct operational pool functions or with

contractual economical agreements.

Increased Revenue. For 30 years (1935 to 1965) utilities were, by lowering costs, reducing their

rates and increasing sales. During this period of falling rates, owing to lags in regulatory rate adjust-

ment, utilities enjoyed a higher revenue and were motivated to be efficient. The costs were reduced

by the installation of larger generators, higher transmission voltages, lower fuel costs, and shifts to

available gas and oil from coal.

From 1973 to 1990, the utilities went through a period of rising costs due to rises in fuel cost,

environmental regulation, diminishing efficiency returns in technology (unit sizes and improvements),

and investing in new technologies such as nuclear plants. During this rising-cost period, the regula-

tory lag in rate adjustments had an adverse economic impact, demanding detailed analysis of past

and present operations and projection of future requirements by financial modeling, optimization

schemes, and simulation techniques.

The expanded list of supply- and demand-side options and the desire to open transmission sys-

tem access have made electric utility planning and operations much more complex. Construction

delays and the desire to minimize capital expenditures have resulted in the electric power system

being used in unexpected ways, and design safety margins must be reduced or stressed.

Reduced Cost. Cost reduction can be achieved by reducing investment per kilowatt of installation

capacity for generation, transmission, and distribution and reducing operating cost per kilowatthour

of energy delivered.

Reduced plant investment can be achieved by proper generation mix and location, increased

transmission and distribution voltages, power pooling, interconnection planning, and coordination to

gain further advantages of scale. Involved also are improved production and distribution facility uti-

lization (i.e., capacity factor and load factor) through peak shaving, reserve sharing, load diversity,

and distribution load balancing. Other means of reducing costs include designing facilities with more

precision and reducing the factor of safety, reducing construction and inventory costs, and operating

the facilities closer to their design limits.

Reduced operating expenditure can be achieved by adopting new technology that requires lower

fuel costs, by improving conventional and established methods of higher energy conversion effi-

ciencies, by reducing energy losses in transmission and distribution facilities, and by interchanging

energy with more economical resources and different time zones in different seasons to take advan-

tage of diversity.

Other means are producing and distributing electricity with fewer personnel; minimizing the

labor force and material inventory required for maintenance, repairs, and restoration of generation,

transmission, and distribution facilities; and reducing customer accounting, general accounting, and

administrative expenses.

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COMPUTER APPLICATIONS IN THE ELECTRIC POWER INDUSTRY

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Improved Quality of Service. Among the requirements in this category are reducing the frequency,

duration, and extent of outages in the power supply; reducing voltage and frequency discontinuities

and sudden excursions (power-line disturbances) to sensitive electronic loads and digital equipment;

and improving customer services through prompt response to inquiries, requests, or complaints. It is

also important to maintain the power supply within prescribed ranges and specifications and to

restore interruptions in service quickly.

Enhanced Environment. Means of improving environmental impact include reducing thermal dis-

charge to natural bodies of water through the use of artificial lakes, cooling towers, and desaliniza-

tion processes and advancing direct conversion of heat energy to electrical energy as by

magnetohydrodynamics, thermionics, and fuel cells. Also involved in conventional systems are

reducing the release of combustion products (sulfur dioxide, nitrogen oxides, carbon dioxide, and

particulate matter) in the atmosphere; reducing the frequency, duration, and intensity of pollution

concentrates in urban areas; and providing more productive uses for fly ash. Safer storage of nuclear

waste is of primary importance.

In the design of systems, selecting remote or underground sites for generating stations, improv-

ing aesthetics by the increased use of underground distribution facilities, and beautifying transmis-

sion towers and lines in harmony with the countryside are all being urged by environmentalists.

Modern transmission- and distribution-line designs reduce magnetic and electric fields in consider-

ation of possible health effects.

Improved Employee Skill

• Labor. In earlier years, the power industry had a labor force of about half a million employees,

a small force when compared with its very high output. In the 1970s, while the generating capacity

doubled, the number of employees remained substantially the same. This was achieved through the

operation of larger installations with fewer personnel, centralized control of generation and trans-

mission, unattended substations, and minimizing maintenance and repair crews by automating dis-

patch procedures. This trend no longer holds.

• Professional. The design and construction of large installations such as generating stations and

extra-high-voltage lines are often contracted out and are engineered and supervised by consulting

firms. Thus, in effect, the consultants provide a common professional pool for all utilities. The

electrical manufacturers have been primarily responsible for research and development of the

industry, and the practice of accepting turnkey contracts is common. Thus manufacturers also pro-

vide a common pool of labor.

However, the advent of nuclear power, extra-high-voltage, and environmental limitations requires

significant changes in utility systems and calls for an increase in both the quality and quantity of pro-

fessional labor. The industry recognizes the need for this rapid increase in in-house skill. This can be

provided by (1) improving the productivity and effectiveness of employees, (2) merging and affili-

ating with neighboring companies forming regional groups, and (3) maintaining aggressive in-house

research and development as well as supporting institutions of higher learning and research organi-

zations by sponsoring research and development efforts.

25.1.3 Spectrum of Computer Usage

A review of engineering and operating computer applications indicates that they fall within several

broad categories, as shown in Fig. 25-2 and as described below.

System Expansion. These applications are related to 20-, 10-, and 5-year construction programs

and cover planning, design, and construction of new facilities. These functions are performed at least

once a year and use long-range load forecasts and other predictions as input data. Competitive pres-

sures and complexity of expansion options demand that engineers have sophisticated interactive

computer tools, decision-support and communication systems, and report-generating mechanisms.

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