Electric Power Principles (eBook)

Professor James Kirtley is currently teaching a course on electric power systems to both undergaraduate and graduate students at MIT (Massachusetts Institue of Technology). He has been a fellow of IEEE since 1990, was awarded the IEEE Third Millenium Medal in 2000 and the Nikola Tesla Award in 2002. Since 2007 Professor Kirtley has been associate editor of IEEE Power Engineering Society's Transactions on Energy Conversion. He lectures outside the university, writes exensively for journals and holds 23 patents. Amongst other areas, his research interests include electric ships, superconducting generator, intelligent monitoring of equipment and systems, and advanced motor/generator machines for kinetic energy storage systems.

Cover 1
Title Page 5
Copyright 6
Contents 7
Preface 13
Chapter 1 Electric Power Systems 15
1.1 Electric Utility Systems 16
1.2 Energy and Power 17
1.2.1 Basics and Units 17
1.3 Sources of Electric Power 17
1.3.1 Heat Engines 18
1.3.2 Power Plants 19
1.3.3 Nuclear Power Plants 22
1.3.4 Hydroelectric Power 23
1.3.5 Wind Turbines 24
1.3.6 Solar Power Generation 26
1.4 Electric Power Plants and Generation 29
1.5 Problems 29
Chapter 2 AC Voltage, Current and Power 31
2.1 Sources and Power 31
2.1.1 Voltage and Current Sources 31
2.1.2 Power 32
2.1.3 Sinusoidal Steady State 32
2.1.4 Phasor Notation 33
2.1.5 Real and Reactive Power 33
2.2 Resistors, Inductors and Capacitors 35
2.2.1 Reactive Power and Voltage 36
2.2.2 Reactive Power Voltage Support 37
2.3 Problems 40
Chapter 3 Transmission Lines 45
3.1 Modeling: Telegrapher’s Equations 46
3.1.1 Traveling Waves 47
3.1.2 Characteristic Impedance 47
3.1.3 Power 49
3.1.4 Line Terminations and Reflections 49
3.1.5 Sinusoidal Steady State 54
3.2 Problems 56
Chapter 4 Polyphase Systems 59
4.0.1 Two-Phase Systems 59
4.1 Three-Phase Systems 61
4.2 Line–Line Voltages 63
4.2.1 Example: Wye and Delta Connected Loads 64
4.2.2 Example: Use of Wye–Delta for Unbalanced Loads 66
4.3 Problems 68
Chapter 5 Electrical and Magnetic Circuits 71
5.1 Electric Circuits 71
5.1.1 Kirchoff ’s Current Law (KCL) 71
5.1.2 Kirchoff ’s Voltage Law (KVL) 72
5.1.3 Constitutive Relationship: Ohm’s Law 72
5.2 Magnetic Circuit Analogies 74
5.2.1 Analogy to KCL 74
5.2.2 Analogy to KVL: Magnetomotive Force 75
5.2.3 Analogy to Ohm’s Law: Reluctance 75
5.2.4 Simple Case 76
5.2.5 Flux Confinement 77
5.2.6 Example: C-Core 77
5.2.7 Example: Core with Different Gaps 78
5.3 Problems 80
Chapter 6 Transformers 85
6.1 Single-phase Transformers 85
6.1.1 Ideal Transformer 86
6.1.2 Deviations from Ideal Transformer 87
6.2 Three-Phase Transformers 89
6.2.1 Example 91
6.3 Problems 94
Chapter 7 Polyphase Lines and Single-Phase Equivalents 99
7.1 Polyphase Transmission and Distribution Lines 99
7.1.1 Example 101
7.2 Introduction To Per-Unit Systems 102
7.2.1 Normalization Of Voltage and Current 102
7.2.2 Three-Phase Systems 104
7.2.3 Networks with Transformers 104
7.2.4 Transforming from one base to another 105
7.2.5 Example: Fault Study 106
7.3 Appendix: Inductances of Transmission Lines 108
7.3.1 Single Wire 108
7.3.2 Mutual Inductance 110
7.3.3 Bundles of Conductors 110
7.3.4 Transposed Lines 111
7.4 Problems 112
Chapter 8 Electromagnetic Forces and Loss Mechanisms 117
8.1 Energy Conversion Process 117
8.1.1 Principle of Virtual Work 118
8.1.2 Coenergy 122
8.2 Continuum Energy Flow 124
8.2.1 Material Motion 125
8.2.2 Additional Issues in Energy Methods 126
8.2.3 Electric Machine Description 130
8.2.4 Field Description of Electromagnetic Force: The Maxwell Stress Tensor 132
8.2.5 Tying the MST and Poynting Approaches together 134
8.3 Surface Impedance of Uniform Conductors 138
8.3.1 Linear Case 138
8.3.2 Iron 142
8.3.3 Magnetization 142
8.3.4 Saturation and Hysteresis 143
8.3.5 Conduction, Eddy Currents and Laminations 145
8.3.6 Eddy Currents in Saturating Iron 147
8.4 Semi-Empirical Method of Handling Iron Loss 150
8.5 Problems 153
Chapter 9 Synchronous Machines 159
9.1 Round Rotor Machines: Basics 160
9.1.1 Operation with a Balanced Current Source 161
9.1.2 Operation with a Voltage Source 161
9.2 Reconciliation of Models 164
9.2.1 Torque Angles 164
9.3 Per-Unit Systems 165
9.4 Normal Operation 166
9.4.1 Capability Diagram 167
9.4.2 Vee Curve 167
9.5 Salient Pole Machines: Two-Reaction Theory 168
9.6 Synchronous Machine Dynamics 171
9.7 Synchronous Machine Dynamic Model 173
9.7.1 Electromagnetic Model 173
9.7.2 Park’s Equations 174
9.7.3 Power and Torque 178
9.7.4 Per-Unit Normalization 178
9.7.5 Equivalent Circuits 181
9.7.6 Transient Reactances and Time Constants 182
9.8 Statement of Simulation Model 183
9.8.1 Example: Transient Stability 184
9.8.2 Equal Area Transient Stability Criterion 184
9.9 Appendix: Transient Stability Code 187
9.10 Appendix: Winding Inductance Calculation 190
9.10.1 Pitch Factor 194
9.10.2 Breadth Factor 194
9.11 Problems 196
Chapter 10 System Analysis and Protection 199
10.1 The Symmetrical Component Transformation 199
10.2 Sequence Impedances 202
10.2.1 Balanced Transmission Lines 202
10.2.2 Balanced Load 203
10.2.3 Possibly Unbalanced Loads 204
10.2.4 Unbalanced Sources 205
10.2.5 Rotating Machines 207
10.2.6 Transformers 207
10.3 Fault Analysis 211
10.3.1 Single Line–neutral Fault 212
10.3.2 Double Line–neutral Fault 213
10.3.3 Line–Line Fault 214
10.3.4 Example of Fault Calculations 215
10.4 System Protection 219
10.4.1 Fuses 220
10.5 Switches 221
10.6 Coordination 222
10.6.1 Ground Overcurrent 222
10.7 Impedance Relays 222
10.7.1 Directional Elements 223
10.8 Differential Relays 224
10.8.1 Ground Fault Protection for Personnel 225
10.9 Zones of System Protection 226
10.10 Problems 226
Chapter 11 Load Flow 233
11.1 Two Ports and Lines 233
11.1.1 Power Circles 235
11.2 Load Flow in a Network 236
11.3 Gauss–Seidel Iterative Technique 238
11.4 Bus Admittance 240
11.4.1 Bus Incidence 240
11.4.2 Alternative Assembly of Bus Admittance 241
11.5 Example: Simple Program 242
11.5.1 Example Network 242
11.6 MATLAB Script for the Load Flow Example 243
11.7 Problems 245
Chapter 12 Power Electronics and Converters in Power Systems 249
12.1 Switching Devices 249
12.1.1 Diode 250
12.1.2 Thyristor 250
12.1.3 Bipolar Transistors 251
12.2 Rectifier Circuits 253
12.2.1 Full-Wave Rectifier 253
12.3 DC–DC Converters 261
12.3.1 Pulse Width Modulation 263
12.3.2 Boost Converter 263
12.4 Canonical Cell 269
12.4.1 Bidirectional Converter 269
12.4.2 H-Bridge 271
12.5 Three-Phase Bridge Circuits 273
12.5.1 Rectifier Operation 273
12.5.2 Phase Control 275
12.5.3 Commutation Overlap 276
12.5.4 AC Side Current Harmonics 279
12.6 High-Voltage DC Transmission 284
12.7 Basic Operation of a Converter Bridge 285
12.7.1 Turn-On Switch 286
12.7.2 Inverter Terminal 286
12.8 Achieving High Voltage 287
12.9 Problems 288
Chapter 13 Induction Machines 295
13.1 Introduction 295
13.2 Induction Machine Transformer Model 297
13.2.1 Operation: Energy Balance 303
13.2.2 Example of Operation 308
13.2.3 Motor Performance Requirements 308
13.3 Squirrel-Cage Machines 310
13.4 Single-Phase Induction Motors 311
13.4.1 Rotating Fields 311
13.4.2 Power Conversion in the Single-Phase Induction Machine 312
13.4.3 Starting of Single-Phase Induction Motors 314
13.4.4 Split Phase Operation 315
13.5 Induction Generators 317
13.6 Induction Motor Control 320
13.6.1 Volts/Hz Control 320
13.6.2 Field Oriented Control 321
13.6.3 Elementary Model 322
13.6.4 Simulation Model 323
13.6.5 Control Model 324
13.6.6 Field-Oriented Strategy 325
13.7 Doubly Fed Induction Machines 327
13.7.1 Steady State Operation 329
13.8 Appendix 1: Squirrel-Cage Machine Model 332
13.8.1 Rotor Currents and Induced Flux 333
13.8.2 Squirrel-Cage Currents 334
13.9 Appendix 2: Single-Phase Squirrel Cage Model 339
13.10 Appendix 3: Induction Machine Winding Schemes 340
13.10.1 Winding Factor for Concentric Windings 343
13.11 Problems 345
Chapter 14 DC (Commutator) Machines 351
14.1 Geometry 351
14.2 Torque Production 352
14.3 Back Voltage 353
14.4 Operation 355
14.4.1 Shunt Operation 356
14.4.2 Separately Excited 357
14.4.3 Machine Capability 359
14.5 Series Connection 360
14.6 Universal Motors 362
14.7 Commutator 363
14.7.1 Commutation Interpoles 365
14.7.2 Compensation 365
14.8 Compound Wound DC Machines 366
14.9 Problems 368
Chapter 15 Permanent Magnets in Electric Machines 371
15.1 Permanent Magnets 371
15.1.1 Permanent Magnets in Magnetic Circuits 373
15.1.2 Load Line Analysis 374
15.2 Commutator Machines 377
15.2.1 Voltage 379
15.2.2 Armature Resistance 380
15.3 Brushless PM Machines 381
15.4 Motor Morphologies 381
15.4.1 Surface Magnet Machines 381
15.4.2 Interior Magnet, Flux Concentrating Machines 382
15.4.3 Operation 383
15.4.4 A Little Two-Reaction Theory 385
15.4.5 Finding Torque Capability 388
15.5 Problems 394
Index 399
EULA 406