ELECTRICAL ENERGY CONVERSION AND TRANSPORT IEEE Press 445 Hoes Lane Piscataway, NJ 08854 IEEE Press Editorial Board 2013 John Anderson, Editor in Chief Linda Shafer George W Arnold Ekram Hossain Om P Malik Saeid Nahavandi David Jacobson Mary Lanzerotti George Zobrist Tariq Samad Dmitry Goldgof Kenneth Moore, Director of IEEE Book and Information Services (BIS) A complete list of titles in the IEEE Press Series on Power Engineering appears at the end of this book ELECTRICAL ENERGY CONVERSION AND TRANSPORT An Interactive Computer-Based Approach SECOND EDITION George G Karady Keith E Holbert IEEE PRESS Cover Design: John Wiley & Sons, Inc Cover Illustration: Courtesy of Siemens AG; Power Lines © Corbis Super Royalty Free/Alamy Copyright © 2013 by the Institute of Electrical and Electronics Engineers, Inc All rights reserved Published by John Wiley & Sons, Inc., Hoboken, New Jersey Published simultaneously in Canada No part of this publication may be reproduced, stored in a retrieval 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Cataloging-in-Publication Data: Karady, George G Electrical energy conversion and transport : an interactive computer-based approach / George G Karady, Keith E Holbert – Second edition pages cm Includes bibliographical references and index ISBN 978-0-470-93699-3 (cloth) Electric power distribution Electric current converters Electric power production–Data processing I Holbert, Keith E II Title TK1001.K36 2012 621.31–dc23 2012029241 Printed in the United States of America 10 CONTENTS Preface and Acknowledgments xv ELECTRIC POWER SYSTEMS 1.1 Electric Networks 1.1.1 Transmission Systems 1.1.2 Distribution Systems 1.2 Traditional Transmission Systems 1.2.1 Substation Components 1.2.2 Substations and Equipment 1.2.3 Gas Insulated Switchgear 1.2.4 Power System Operation in Steady-State Conditions 1.2.5 Network Dynamic Operation (Transient Condition) 1.3 Traditional Distribution Systems 1.3.1 Distribution Feeder 1.3.2 Residential Electrical Connection 1.4 Intelligent Electrical Grids 1.4.1 Intelligent High-Voltage Transmission Systems 1.4.2 Intelligent Distribution Networks 1.5 Exercises 1.6 Problems 6 17 18 20 20 21 24 26 26 28 28 29 ELECTRIC GENERATING STATIONS 2.1 Fossil Power Plants 2.1.1 Fuel Storage and Handling 2.1.2 Boiler 2.1.3 Turbine 2.1.4 Generator and Electrical System 30 34 34 35 41 43 v vi CONTENTS 2.1.5 Combustion Turbine 2.1.6 Combined Cycle Plants 2.2 Nuclear Power Plants 2.2.1 Nuclear Reactor 2.2.2 Pressurized Water Reactor 2.2.3 Boiling Water Reactor 2.3 Hydroelectric Power Plants 2.3.1 Low Head Hydroplants 2.3.2 Medium- and High-Head Hydroplants 2.3.3 Pumped Storage Facility 2.4 Wind Farms 2.5 Solar Power Plants 2.5.1 Photovoltaics 2.5.2 Solar Thermal Plants 2.6 Geothermal Power Plants 2.7 Ocean Power 2.7.1 Ocean Tidal 2.7.2 Ocean Current 2.7.3 Ocean Wave 2.7.4 Ocean Thermal 2.8 Other Generation Schemes 2.9 Electricity Generation Economics 2.9.1 O&M Cost 2.9.2 Fuel Cost 2.9.3 Capital Cost 2.9.4 Overall Generation Costs 2.10 Load Characteristics and Forecasting 2.11 Environmental Impact 2.12 Exercises 2.13 Problems 47 48 49 50 53 55 56 59 60 62 63 66 66 70 72 73 74 75 75 76 76 77 79 79 80 81 81 85 86 86 SINGLE-PHASE CIRCUITS 3.1 Circuit Analysis Fundamentals 3.1.1 Basic Definitions and Nomenclature 3.1.2 Voltage and Current Phasors 3.1.3 Power 3.2 AC Circuits 89 90 90 91 92 94 vii CONTENTS 3.3 Impedance 3.3.1 Series Connection 3.3.2 Parallel Connection 3.3.3 Impedance Examples Loads 3.4.1 Power Factor 3.4.2 Voltage Regulation Basic Laws and Circuit Analysis Techniques 3.5.1 Kirchhoff’s Current Law 3.5.2 Kirchhoff’s Voltage Law 3.5.3 Thévenin’s and Norton’s Theorems Applications of Single-Phase Circuit Analysis Summary Exercises Problems 96 100 100 104 109 111 116 116 117 123 127 128 140 141 141 THREE-PHASE CIRCUITS 4.1 Three-Phase Quantities 4.2 Wye-Connected Generator 4.3 Wye-Connected Loads 4.3.1 Balanced Wye Load (Four-Wire System) 4.3.2 Unbalanced Wye Load (Four-Wire System) 4.3.3 Wye-Connected Three-Wire System 4.4 Delta-Connected System 4.4.1 Delta-Connected Generator 4.4.2 Balanced Delta Load 4.4.3 Unbalanced Delta Load 4.5 Summary 4.6 Three-Phase Power Measurement 4.6.1 Four-Wire System 4.6.2 Three-Wire System 4.7 Per-Unit System 4.8 Symmetrical Components 4.8.1 Calculation of Phase Voltages from Sequential Components 4.8.2 Calculation of Sequential Components from Phase Voltages 4.8.3 Sequential Components of Impedance Loads 145 146 151 155 156 158 160 162 162 163 166 168 174 175 175 177 182 3.4 3.5 3.6 3.7 3.8 3.9 182 183 184 viii CONTENTS 4.9 Application Examples 4.10 Exercises 4.11 Problems 188 203 204 TRANSMISSION LINES AND CABLES 5.1 Construction 5.2 Components of the Transmission Lines 5.2.1 Towers and Foundations 5.2.2 Conductors 5.2.3 Insulators 5.3 Cables 5.4 Transmission Line Electrical Parameters 5.5 Magnetic Field Generated by Transmission Lines 5.5.1 Magnetic Field Energy Content 5.5.2 Single Conductor Generated Magnetic Field 5.5.3 Complex Spatial Vector Mathematics 5.5.4 Three-Phase Transmission Line-Generated Magnetic Field 5.6 Transmission Line Inductance 5.6.1 External Magnetic Flux 5.6.2 Internal Magnetic Flux 5.6.3 Total Conductor Magnetic Flux 5.6.4 Three-Phase Line Inductance 5.7 Transmission Line Capacitance 5.7.1 Electric Field Generation 5.7.2 Electrical Field around a Conductor 5.7.3 Three-Phase Transmission Line Generated Electric Field 5.7.4 Three-Phase Line Capacitance 5.8 Transmission Line Networks 5.8.1 Equivalent Circuit for a Balanced System 5.8.2 Long Transmission Lines 5.9 Concept of Transmission Line Protection 5.9.1 Transmission Line Faults 5.9.2 Protection Methods 5.9.3 Fuse Protection 5.9.4 Overcurrent Protection 5.9.5 Distance Protection 207 208 215 215 216 218 223 224 225 229 230 233 234 239 240 241 243 244 249 249 250 256 271 273 273 277 282 282 285 285 285 288 CONTENTS ix 5.10 Application Examples 5.10.1 Mathcad® Examples 5.10.2 PSpice®: Transient Short-Circuit Current in Transmission Lines 5.10.3 PSpice: Transmission Line Energization 5.11 Exercises 5.12 Problems 289 289 ELECTROMECHANICAL ENERGY CONVERSION 6.1 Magnetic Circuits 6.1.1 Magnetic Circuit Theory 6.1.2 Magnetic Circuit Analysis 6.1.3 Magnetic Energy 6.1.4 Magnetization Curve 6.1.5 Magnetization Curve Modeling 6.2 Magnetic and Electric Field Generated Forces 6.2.1 Electric Field-Generated Force 6.2.2 Magnetic Field-Generated Force 6.3 Electromechanical System 6.3.1 Electric Field 6.3.2 Magnetic Field 6.4 Calculation of Electromagnetic Forces 6.5 Applications 6.5.1 Actuators 6.5.2 Transducers 6.5.3 Permanent Magnet Motors and Generators 6.5.4 Microelectromechanical Systems 6.6 Summary 6.7 Exercises 6.8 Problems 313 314 315 317 323 324 329 336 336 337 343 344 345 347 352 353 356 362 365 368 368 369 TRANSFORMERS 7.1 Construction 7.2 Single-Phase Transformers 7.2.1 Ideal Transformer 7.2.2 Real Transformer 7.2.3 Determination of Equivalent Transformer Circuit Parameters 375 376 381 382 391 302 304 307 308 399 x CONTENTS 7.3 7.4 7.5 Three-Phase Transformers 7.3.1 Wye–Wye Connection 7.3.2 Wye–Delta Connection 7.3.3 Delta–Wye Connection 7.3.4 Delta–Delta Connection 7.3.5 Summary 7.3.6 Analysis of Three-Phase Transformer Configurations 7.3.7 Equivalent Circuit Parameters of a Three-Phase Transformer 7.3.8 General Program for Computing Transformer Parameters 7.3.9 Application Examples 7.3.10 Concept of Transformer Protection Exercises Problems SYNCHRONOUS MACHINES 8.1 Construction 8.1.1 Round Rotor Generator 8.1.2 Salient Pole Generator 8.1.3 Exciter 8.2 Operating Concept 8.2.1 Main Rotating Flux 8.2.2 Armature Flux 8.3 Generator Application 8.3.1 Loading 8.3.2 Reactive Power Regulation 8.3.3 Synchronization 8.3.4 Static Stability 8.4 Induced Voltage and Armature Reactance Calculation 8.4.1 Induced Voltage Calculation 8.4.2 Armature Reactance Calculation 8.5 Concept of Generator Protection 8.6 Application Examples 8.7 Exercises 8.8 Problems 408 410 415 418 420 420 421 429 432 435 447 450 451 456 456 457 459 462 465 465 468 472 472 472 473 474 487 488 496 507 511 535 536 Semiconductor Switches 695 'UDLQ ' *DWH * 6RXUFH Figure 11.21. Power metal–oxide–semiconductor field-effect transistor (MOSFET) symbol &ROOHFWRU *DWH (PLWWHU Figure 11.22. Insulated gate bipolar transistor (IGBT) symbol In power circuits, the MOSFET is driven by a relatively large gate pulse, which turns on the device and drives it to saturation For this mode, the voltage drop is a few volts across the device Generally, the maximum ratings of power MOSFETS are in the range of a few hundred amperes (200–300 A) and around 1000–1500 V The operating frequency can be in the megahertz range A typical application of the power MOSFET is in pulsewidth-modulation (PWM) circuits 11.3.5. Insulated Gate Bipolar Transistor The insulated gate bipolar transistor (IGBT) is a three-terminal device, which is used as a high-speed switch Because of the relatively low reverse breakdown voltage, the device is shunted by a diode in the reverse direction The IGBT symbol is shown in Figure 11.22 The current–voltage characteristics of a typical 600 A, 600 V IGBT are given in Figure 11.23 The graph indicates that the gate-emitter voltage should be around 20 V, which results in collector-emitter voltage of approximately 2 V at a collector current of 600 A The current flows from the collector to the emitter, when the device is forward biased and a positive (gate-emitter) voltage triggers the gate pulse The removal of the gate pulse interrupts the current 696 Introduction to Power Electronics and Motor Control OUTPUT CHARACTERISTICS (TYPICAL) COLLECTOR CURRENT, IC, (AMPERES) 1200 VGE = 20 V Tj = 25 °C 1000 12 15 800 11 600 10 400 200 8 10 COLLECTOR-EMITTER VOLTAGE, VGE, (VOLTS) Figure 11.23. Output characteristics of a 600 V, 600 A IGBT module (Source: Power Semiconductor Data Book, Powerex, Inc., Youngwood, PA, 1988) TABLE 11.1. Summary of Important Semiconductor Power Switch Characteristics Switch Diode Thyristor (SCR) GTO MOSFET and IGBT Important Characteristics Applications No gate Gate control Gate control; on–off control On–off control multiple times per cycle (i.e., high speed) Rectifier Rectifier and inverter use Rectifier and inverter use Mostly for inverter, but can use in a rectifier Generally, the maximum rating of power IGBTs is in the range of a few hundred amperes (400–800 A) and around less than 2000 V The operating frequency can be in the kilohertz range A typical application of the power IGBT is in pulse-width-modulation (PWM) circuits 11.3.6. Summary A critical characteristic of all these semiconductor switches is that current is allowed to flow in only one direction A comparison and contrast of other important characteristics and the primary use for these switches are summarized in Table 11.1 Rectifiers 697 11.4. RECTIFIERS Rectifiers convert ac voltage and current to dc voltage and current Typical power applications include: battery chargers, DC motor drives, power supplies (for computers, appliances, uninterruptible power supplies, etc.), and generator excitation systems In most cases, the rectifier must control the output dc voltage or must keep it at a constant level even if the load and/or the supply ac voltages change This is achieved by using controllable switches like thyristors, GTOs, MOSFETs, or IGBTs in the rectifier circuit We begin this section with analyses of simple diode rectifiers such as the bridge rectifier Afterward, both single- and three-phase controlled rectifiers are presented 11.4.1. Simple Passive Diode Rectifiers An uncontrolled (passive) rectifier can be formed by simply using diodes Such diode rectifiers are typically used in the power supplies of popular consumer electronics, and are one of the first circuits studied in an electronics course These “dc transformers” (a prevalent misnomer) first reduce household voltage (120 Vac) down to around 5–12 Vac, and then use diodes to rectify the voltage to a dc output These power supplies are sometimes referred to as a power cube transformer because of their cubical shape Three diode rectifier circuits are shown in Figure 11.24 A half-wave rectifier is constructed using a single diode The output (V0) of the half-wave rectifier (Fig 11.24a) follows the positive half-cycle of the ac voltage, but is zero during the negative portion of the cycle: Vac (t ) T V0 (t ) = 0 0[...]... reader first familiarize himself or herself with the information in Appendix A (“Introduction to Mathcad”), since Mathcad expressions are utilized throughout the text This will allow the reader to reap the full benefits of this delivery method Although this book employs Mathcad, MATLAB, and PSpice, other xvii PREFACE AND ACKNOWLEDGMENTS computational software can also be utilized effectively—this includes... case of Bus 1 fault provides the current paths It is observed from this scenario that the CBs and buses must be specified to carry all three load currents simultaneously Specifically in this case the full supply current passes through CBA 4 and 1, and Bus 1 Case 2: CBA 5 Fails Closed. If CBA 5 fails in the closed position (that is, the CB cannot be opened), then a short circuit in T3 cannot be isolated