Electric Energy Systems

Analysis and Operation

Antonio Gomez-Exposito, Antonio J. Conejo, Claudio Canizares, Antonio Gomez-Exposito, Antonio J. Conejo, Claudio Canizares

• Publisher: CRC Press
• Year: 2018
• Print ISBN: 9781138724792
• eBook ISBN: 9781351754491
• Topic: Technology & Engineering
• Subtopic: Electrical Engineering & Telecommunications
• Index: Technology & Engineering

Electric Energy Systems, Second Edition provides an analysis of electric generation and transmission systems that addresses diverse regulatory issues. It includes fundamental background topics, such as load flow, short circuit analysis, and economic dispatch, as well as advanced topics, such as harmonic load flow, state estimation, voltage and frequency control, electromagnetic transients, etc. The new edition features updated material throughout the text and new sections throughout the chapters. It covers current issues in the industry, including renewable generation with associated control and scheduling problems, HVDC transmission, and use of synchrophasors (PMUs). The text explores more sophisticated protections and the new roles of demand, side management, etc. Written by internationally recognized specialists, the text contains a wide range of worked out examples along with numerous exercises and solutions to enhance understanding of the material.

Features

Integrates technical and economic analyses of electric energy systems.

Covers HVDC transmission.

Addresses renewable generation and the associated control and scheduling problems.

Analyzes electricity markets, electromagnetic transients, and harmonic load flow.

Features new sections and updated material throughout the text.

Includes examples and solved problems.

1

Electric Energy Systems

An Overview

Ignacio J. Pérez-Arriaga, Hugh Rudnick, and Michel Rivier Abbad

Contents

1.1A First Vision

1.1.1The Energy Challenges in Modern Times

1.1.2Characteristics of Electricity

1.1.3Electrical Energy Systems: The Biggest Industrial System Created by Humankind

1.1.4History

1.1.4.1Technological Aspects

1.1.4.2Organizational Aspects

1.1.5Environmental Impact and Climate Change

1.2The Technological Environment

1.2.1Electric Power System Structure

1.2.2Consumption and Demand Management

1.2.2.1Demand Growth

1.2.2.2Demand Profiles

1.2.2.3Demand-Side Management

1.2.2.4Service Quality

1.2.3Generation: Conventional and Renewables

1.2.3.1Different Generation Technologies

1.2.3.2The Why’s and Wherefore’s of a Generation Mix

1.2.4Transmission

1.2.4.1Power Lines

1.2.4.2Substations

1.2.5Distribution

1.2.6Control and Protection

1.3The Economic Environment

1.3.1The Electric Sector and Economic Activity

1.3.2Expansion and Operation in the Traditional Context

1.3.2.1Long Term

1.3.2.2Medium Term

1.3.2.3Short Term

1.3.2.4Real Time

1.3.3Expansion and Operation in the New Regulatory Context

1.3.3.1Long Term

1.3.3.2Medium Term

1.3.3.3Short Term

1.3.3.4Real Time

1.4The Regulatory and Social Environment

1.4.1Traditional Regulation and Regulation of Competitive Markets

1.4.2New Regulatory Environment

1.4.2.1Motivation

1.4.2.2Fundamentals

1.4.2.3Requirements

1.4.3Nature of Electric Activities

1.4.3.1Unbundling of Activities

1.4.3.2Generation Activities

1.4.3.3Network Activities

1.4.3.4Transmission

1.4.3.5Distribution

1.4.3.6Transaction Activities

1.4.3.7Ancillary Activities

1.4.3.8Coordination Activities

1.4.4The Integration of Renewables

1.4.5Practical Aspects of Regulation

1.4.5.1Transition to Competition

1.4.5.2Stranded Benefits

1.4.5.3Environmental Costs

1.4.5.4Structural Aspects

1.4.5.5Security of Supply in Generation

1.4.5.6Independent Regulatory Body

1.4.6Environmental and Social Restrictions

1.4.7Universal Access to Energy

1.4.8The Trends in Regulation: International Experiences

1.5Modeling Requirements of Modern Electric Energy Systems

1.6Future Challenges and Prospects

References

1.1A First Vision

1.1.1The Energy Challenges in Modern Times

Energy is a fundamental ingredient of modern society and its supply impacts directly on the social and economic development of nations. Economic growth and energy consumption go hand in hand. The development and quality of our life and our work are totally dependent on a continuous, abundant, economic and environmental-friendly energy supply. Coal, oil and natural gas have been the traditional basic energy sources, and this reliance on energy for economic growth has historically implied dependence on third parties for energy supply, with geopolitical connotations arising, as these energy resources have not been generally in places where high consumption has developed. Energy has transformed itself in a new form of international political power, utilized by owners of energy resources (mainly oil and natural gas). At some time, concerns aroused on the decline of volumes of oil and natural gas (coal remains an abundant resource) and on the consequent energy price increases in the medium to long term. However, the advances in exploration and drilling technologies, and the development of shale gas, have minimized this fear. It is actually the climate change which has driven the major changes on this regard. Greenhouse emissions are heavily penalizing the traditional resources, being renewable sources (mainly wind but fundamentally solar) seen as the future main energy resources, as the backbone of a decarbonized abundant energy supply. Strong geopolitical impacts may be expected from such a transformation.

Within that framework, electricity has become a favorite form of energy usage at the consumer end, with coal, oil, gas, uranium, hydro, wind, solar irradiation, and other basic resources used to generate electricity. With its versatility and controllability, instant availability and consumer-end cleanliness, electricity has become an indispensable, multipurpose form of energy. Its domestic use now extends far beyond the initial purpose, to which it owes its colloquial name (“light” or “lights”), and has become virtually irreplaceable in kitchens—for refrigerators, ovens, and cookers or ranges, and any number of other appliances—and in the rest of the house as well, for air conditioner, radio, television, computers, and the like. But electricity usage is even broader in the commercial and industrial domains: in addition to providing power for lighting and air conditioning, it drives motors with a host of applications: lifts, cranes, mills, pumps, compressors, lathes, or other machine tools, and so on and so forth: it is nearly impossible to imagine an industrial activity that does not use some sort of electricity. Being also electricity one of the energy forms where renewable sources can more economically an efficiently substitute traditional greenhouse emitting energy sources, electrification of other sectors such as the terrestrial transport or the heating might be expected. Thus, modern societies have become totally dependent on an abundant electricity supply and it is alike they will become even more dependent on the future.

1.1.2Characteristics of Electricity

At first glance, electricity must appear to be a commodity much like any other on consumers’ list of routine expenses. In fact, this may be the point of view that prompted the revolution that has rocked electric energy systems worldwide, as they have been engulfed in the wave of liberalization and deregulation that has changed so many other sectors of the economy [12,13,20]. And yet electricity is defined by a series of properties that distinguish it from other products, an argument often wielded in an attempt to prevent or at least limit the implementation of such changes in the electricity industry. The chief characteristic of electricity as a product that differentiates it from all others is that it is not susceptible, in practice, to being stored or inventoried. Electricity can, of course, be stored in batteries, but price, performance, and inconvenience makes this impractical up to now for handling the amounts of energy usually needed in the developed world. Therefore, electricity must be generated and transmitted as it is consumed, which means that electric systems are dynamic and highly complex, as well as immense. At any given time, these vast dynamic systems must strike a balance between generation and demand, and the disturbance caused by the failure of a single component may be transmitted across the entire system almost instantaneously. This sobering fact plays a decisive role in the structure, operation, and planning of electric energy systems, as discussed below.

Another peculiarity of electricity is its transmission: this is not a product that can be shipped in “packages” from its origin to destination by the most suitable medium at any given time. Electric power is transmitted over grids in which the pathway cannot be chosen at will, but is determined by Kirchhoff’s laws, whereby current distribution depends on impedance in the lines and other elements through which electricity flows [4]. Except in very simple cases, all that can be said is that electric power flows into the system at one point and out of it at another, because ascribing the flow to any given path is extraordinarily complex and somewhat arbitrary. Moreover, according to these laws of physics, the alternative routes that form the grid are highly interdependent, so that any variation in a transmission facility may cause the instantaneous reconfiguration of power flows and that, in turn, may have a substantial effect on other facilities. All this renders the dynamic balance referred to in the preceding paragraph even more complex.

1.1.3Electrical Energy Systems: The Biggest Industrial System Created by Humankind

Indeed, for all its apparent grandiloquence, the introductory sentence to this unit may be no exaggeration. The combination of the extreme convenience of utility and countless applications of electricity, on the one hand, and its particularities, on the other hand, has engendered these immense and sophisticated industrial systems. Their size has to do with their scope, as they are designed to carry electricity practically to any place inhabited by human beings from electric power stations located wherever a supply of primary energy—in the form of potential energy in moving water or any of several fuels—is most readily available. Carrying electric power from place of origin to place of consumption calls for transmission grids and distribution grids or networks that interconnect the entire system and enable it to work as an integrated whole. Their sophistication is a result of the complexity of the problem, determined by the characteristics discussed above: the apparently fragile dynamic equilibrium between generation and demand that must be permanently maintained is depicted in the highly regular patterns followed by the characteristic magnitudes involved—the value and frequency of voltage and currents as well as the waveform of these signals. Such regularity is achieved with complicated control systems that, based on the innumerable measurements that continuously monitor system performance, adapt its response to constantly changing conditions. A major share of these control tasks is performed by powerful computers in energy management centers running a host of management applications: some estimate demand at different grid buses several minutes, hours, days, or months in advance; other models determine the generation needed to meet this demand; yet other programs compute the flow in system lines and transformers and the voltage at grid buses under a number of assumptions on operating conditions or component failure, and determine the most suitable action to take in each case. Others study the dynamic behavior of the electric power system under various types of disturbance [9]. Some models not only attempt to determine the most suitable control measures to take when a problem arises, but also to anticipate their possible occurrence, modifying system operating conditions to reduce or eliminate its vulnerability to the most likely contingencies.

This, however, is not all: the economic aspect of the problem must also be borne in mind. The actors that make the system work may be private companies that logically attempt to maximize their earnings or public institutions that aim to minimize the cost of the service provided. In either case, the economic implications of the decisions made cannot be ignored, except, of course, where system safety is at stake. The system operates under normal conditions practically always, so there is sufficient time to make decisions that are not only safe, but also economically sound. Hence, when demand rises foreseeably during the day, power should be drawn from the facilities with unused capacity that can generate power most efficiently. The objective is to meet daily load curve needs with power generated at the lowest and least variable cost. This new dimension in the operation of electric energy systems is present in all timescales [8]: from the ho...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Contents
• List of Figures
• List of Tables
• Preface
• Preface to the First Edition
• Editors
• Contributors
• Chapter 1: Electric Energy Systems: An Overview
• Chapter 2: Steady-State Single-Phase Models of Power System Components
• Chapter 3: Load Flow
• Chapter 4: State Estimation
• Chapter 5: Economics of Electricity Generation
• Chapter 6: Optimal and Secure Operation of Transmission Systems
• Chapter 7: Three-Phase Linear and Nonlinear Models of Power System Components
• Chapter 8: Fault Analysis and Protection Systems
• Chapter 9: Frequency and Voltage Control
• Chapter 10: Angle, Voltage, and Frequency Stability
• Chapter 11: Three-Phase Power Flow and Harmonic Analysis
• Chapter 12: Electromagnetic Transients Analysis
• Appendix A: Solution of Linear Equation Systems
• Appendix B: Mathematical Programing
• Appendix C: Dynamic Models of Electric Machines
• Index