Power Generation, Operation, and Control

Allen J. Wood, Bruce F. Wollenberg, Gerald B. Sheblé

• Publisher: Wiley-Interscience
• Year: 2013
• Print ISBN: 9780471790556
• eBook ISBN: 9781118733912
• Edition: 3
• Topic: Technology & Engineering
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

A thoroughly revised new edition of the definitive work on power systems best practices

In this eagerly awaited new edition, Power Generation, Operation, and Control continues to provide engineers and academics with a complete picture of the techniques used in modern power system operation. Long recognized as the standard reference in the field, the book has been thoroughly updated to reflect the enormous changes that have taken place in the electric power industry since the Second Edition was published seventeen years ago.

With an emphasis on both the engineering and economic aspects of energy management, the Third Edition introduces central "terminal" characteristics for thermal and hydroelectric power generation systems, along with new optimization techniques for tackling real-world operating problems. Readers will find a range of algorithms and methods for performing integrated economic, network, and generating system analysis, as well as modern methods for power system analysis, operation, and control. Special features include:

• State-of-the-art topics such as market simulation, multiple market analysis, contract and market bidding, and other business topics
• Chapters on generation with limited energy supply, power flow control, power system security, and more
• An introduction to regulatory issues, renewable energy, and other evolving topics
• New worked examples and end-of-chapter problems
• A companion website with additional materials, including MATLAB programs and power system sample data sets

1

INTRODUCTION

1.1 PURPOSE OF THE COURSE

The objectives of a first-year, one-semester graduate course in electric power generation, operation, and control include the desire to:

1. Acquaint electric power engineering students with power generation systems, their operation in an economic mode, and their control.

2. Introduce students to the important “terminal” characteristics for thermal and hydroelectric power generation systems.

3. Introduce mathematical optimization methods and apply them to practical operating problems.

4. Introduce methods for solving complicated problems involving both economic analysis and network analysis and illustrate these techniques with relatively simple problems.

5. Introduce methods that are used in modern control systems for power generation systems.

6. Introduce “current topics”: power system operation areas that are undergoing significant, evolutionary changes. This includes the discussion of new techniques for attacking old problems and new problem areas that are arising from changes in the system development patterns, regulatory structures, and economics.

1.2 COURSE SCOPE

Topics to be addressed include

1. Power generation characteristics

2. Electric power industry as a business

3. Economic dispatch and the general economic dispatch problem

4. Thermal unit economic dispatch and methods of solution

5. Optimization with constraints

6. Optimization methods such as linear programming, dynamic programming, nonlinear optimization, integer programming, and interior point optimization

7. Transmission system effects

a. Power flow equations and solutions

b. Transmission losses

c. Effects on scheduling

8. The unit commitment problem and solution methods

a. Dynamic programming

b. Lagrange relaxation

c. Integer programming

9. Generation scheduling in systems with limited energy supplies including fossil fuels and hydroelectric plants, need to transport energy supplies over networks such as pipelines, rail networks, and river/reservoir systems, and power system security techniques

10. Optimal power flow techniques

11. Power system state estimation

12. Automatic generation control

13. Interchange of power and energy, power pools and auction mechanisms, and modern power markets

14. Load forecasting techniques

In many cases, we can only provide an introduction to the topic area. Many additional problems and topics that represent important, practical problems would require more time and space than is available. Still others, such as light-water moderated reactors and cogeneration plants, could each require several chapters to lay a firm foundation. We can offer only a brief overview and introduce just enough information to discuss system problems.

1.3 ECONOMIC IMPORTANCE

The efficient and optimum economic operation and planning of electric power generation systems have always occupied an important position in the electric power industry. Prior to 1973 and the oil embargo that signaled the rapid escalation in fuel prices, electric utilities in the United States spent about 20% of their total revenues on fuel for the production of electrical energy. By 1980, that figure had risen to more than 40% of the total revenues. In the 5 years after 1973, U.S. electric utility fuel costs escalated at a rate that averaged 25% compounded on an annual basis. The efficient use of the available fuel is growing in importance, both monetarily and because most of the fuel used represents irreplaceable natural resources.

An idea of the magnitude of the amounts of money under consideration can be obtained by considering the annual operating expenses of a large utility for purchasing fuel. Assume the following parameters for a moderately large system:

Annual peak load: 10,000 MW

Annual load factor: 60%

Average annual heat rate for converting fuel to electric energy: 10,500 Btu/kWh

Average fuel cost: $3.00 per million Btu (MBtu), corresponding to oil priced at 18$/bbl

With these assumptions, the total annual fuel cost for this system is as follows:

Annual energy produced: 10⁷ kW × 8760 h/year × 0.60 = 5.256 × 10¹⁰ kWh

Annual fuel consumption: 10, 500 Btu/kWh × 5.256 × 10¹⁰ kWh = 55.188 × 10¹³ Btu

Annual fuel cost: 55.188 × 10¹³ Btu × 3 × 10^{− 6} $/Btu = $1.66 billion

To put this cost in perspective, it represents a direct requirement for revenues from the average customer of this system of 3.15 cents/kWh just to recover the expense for fuel.

A savings in the operation of this system of a small percent represents a significant reduction in operating cost as well as in the quantities of fuel consumed. It is no wonder that this area has warranted a great deal of attention from engineers through the years.

Periodic changes in basic fuel price levels serve to accentuate the problem and increase its economic significance. Inflation also causes problems in developing and presenting methods, techniques, and examples of the economic operation of electric power generating systems.

1.4 DEREGULATION: VERTICAL TO HORIZONTAL

In the 1990s, many electric utilities including government-owned electric utilities, private investor–owned electric utilities were “deregulated.” This has had profound effects on the operation of electric systems where implemented. This topic is dealt with in an entire chapter of its own in this text as Chapter 2.

1.5 PROBLEMS: NEW AND OLD

This text represents a progress report in an engineering area that has been and is still undergoing rapid change. It concerns established engineering problem areas (i.e., economic dispatch and control of interconnected systems) that have taken on new importance in recent years. The original problem of economic dispatch for thermal systems was solved by numerous methods years ago. Recently there has been a rapid growth in applied mathematical methods and the availability of computational capability for solving problems of this nature so that more involved problems have been successfully solved.

The classic problem is the economic dispatch of fossil-fired generation systems to achieve minimum operating cost. This problem area has taken on a subtle twist as the public has become increasingly concerned with environmental matters, so “economic dispatch” now includes the dispatch of systems to minimize pollutants and conserve various forms of fuel, as well as to achieve minimum costs. In addition, there is a need to expand the limited economic optimization problem to incorporate constraints on system operation to ensure the “security” of the system, thereby preventing the collapse of the system due to unforeseen conditions. The hydrothermal coordination problem is another optimum operating problem area that has received a great deal of attention. Even so, there are difficult problems involving hydrothermal coordination that cannot be solved in a theoretically satisfying fashion in a rapid and efficient computational manner.

The post–World War II period saw the increasing installation of pumped-storage hydroelectric plants in the United States and a great deal of interest in energy storage systems. These storage systems involve another difficult aspect of the optimum economic operating problem. Methods are available for solving coordination of hydroelectric, thermal, and pumped-storage electric systems. However, closely associated with this economic dispatch problem is the problem of the proper commitment of an array of units out of a total array of units to serve the expected load demands in an “optimal” manner.

A great deal of progress and change has occurred in the 1985–1995 decade. Both the unit commitment and optimal economic maintenance scheduling problems have seen new methodologies and computer programs developed. Transmission losses and constraints are integrated with scheduling using methods based on the incorporation of power flow equations in the economic dispatch process. This permits the development of optimal economic dispatch conditions that do not result in overloading system elements or voltage magnitudes that are intolerable. These “optimal power flow” techniques are applied to scheduling both real and reactive power sources as well as establishing tap positions for transformers and phase shifters.

In recent years, the political climate in many countries has changed, resulting in the introduction of more privately owned electric power facilities and a reduction or elimination of governmentally sponsored generation and transmission organizations. In some countries, previously nationwide systems have been privatized. In both these countries and in countries such as the United States, where electric utilities have been owned by a variety of bodies (e.g., consumers, shareholders, as well as government agencies), there has been a movement to introduce both privately owned generation companies and larger cogeneration plants that may provide energy to utility customers. These two groups are referred to as independent power producers (IPPs). This trend is coupled with a movement to provide access to the transmission system for these nonutility power generators as well as to other interconnected utilitie...

Table of contents

• COVER
• TITLE PAGE
• COPYRIGHT PAGE
• DEDICATION
• PREFACE TO THE THIRD EDITION
• PREFACE TO THE SECOND EDITION
• PREFACE TO THE FIRST EDITION
• ACKNOWLEDGMENT
• ABOUT THE COMPANION WEBSITE
• 1 INTRODUCTION
• 2 INDUSTRIAL ORGANIZATION, MANAGERIAL ECONOMICS, AND FINANCE
• 3 ECONOMIC DISPATCH OF THERMAL UNITS AND METHODS OF SOLUTION
• 4 UNIT COMMITMENT
• 5 GENERATION WITH LIMITED ENERGY SUPPLY
• 6 TRANSMISSION SYSTEM EFFECTS
• 7 POWER SYSTEM SECURITY
• 8 OPTIMAL POWER FLOW
• 9 INTRODUCTION TO STATE ESTIMATION IN POWER SYSTEMS
• 10 CONTROL OF GENERATION
• 11 INTERCHANGE, POOLING, BROKERS, AND AUCTIONS
• 12 SHORT-TERM DEMAND FORECASTING
• INDEX