Thyristor-Based FACTS Controllers and Electrical Transmission Systems

Front Matter......Page 1
Appendices......Page 0
Table of Contents......Page 3
1.2 Electrical Transmission Networks......Page 16
1.3.1 Automatic Generation Control (AGC)......Page 18
1.3.2 Excitation Control......Page 19
1.3.4 Phase-Shifting Transformers......Page 20
1.4 Flexible AC Transmission System (FACTS)......Page 21
1.4.1 Advances in Power-Electronics Switching Devices......Page 22
1.4.2 Principles and Applications of Semiconductor Switches......Page 23
1.5 Emerging Transmission Networks......Page 27
References......Page 28
2.1 Reactive Power......Page 31
2.2.1.1 Load Compensation......Page 33
2.2.2 Lossless Distributed Parameter Lines......Page 34
2.2.2.1 Symmetrical Lines......Page 36
2.2.2.2 Midpoint Conditions of a Symmetrical Line......Page 37
2.2.2.3 Case Study......Page 38
2.3 Passive Compensation......Page 48
2.3.2 Series Compensation......Page 49
2.3.3 Effect on Power-Transfer Capacity......Page 50
2.3.3.1 Series Compensation......Page 51
2.3.3.2 Shunt Compensation......Page 52
References......Page 54
3.1 Introduction......Page 55
3.2.1 Configuration......Page 56
3.2.2.2 Dynamic Reactive-Power Support at HVDC Terminals......Page 57
3.3.1 Configuration......Page 58
3.3.2 Operating Characteristics......Page 60
3.4.1 The Single-Phase TCR......Page 62
3.4.2 The 3-Phase TCR......Page 67
3.4.5 The 12-Pulse TCR......Page 71
3.4.6.1 Operating Characteristics without Voltage Control......Page 74
3.4.6.1.1 Voltage-Current Characteristic or Operating Characteristic......Page 75
3.4.6.2 Operating Characteristic with Voltage Control......Page 76
3.5 The Thyristor-Controlled Transformer (TCT)......Page 77
3.6.1 Configuration......Page 78
3.6.2.1 Without the Step-down Transformer......Page 79
3.6.2.2.1 The Compensator Susceptance......Page 80
3.6.2.2.2 The Transformer-Secondary Voltage......Page 82
3.6.2.2.4 Losses......Page 83
3.7 The Mechanically Switched Capacitor-Thyristor Controlled Reactor (MSC-TCR)......Page 85
3.8.1 Switching a Capacitor to a Voltage Source......Page 86
3.8.2 Switching a Series Connection of a Capacitor and Reactor......Page 87
3.8.2.1 The Term Involving Fundamental Frequency, omega_0......Page 88
3.8.2.2 The Terms Involving Natural Resonance Frequency, omega_n......Page 89
3.8.2.3 Practical Switching Strategies......Page 90
3.8.4 The TSC Configuration......Page 93
3.8.5 Operating Characteristic......Page 96
3.9.1 Configuration......Page 97
3.9.2.1.1 Calculation of the Operating-Range Limits......Page 98
3.9.3 Current Characteristic......Page 99
3.9.4 Susceptance Characteristic......Page 101
3.9.5 Mismatched TSC-TCR......Page 102
3.10.1 Losses......Page 104
References......Page 106
4.2 Measurement Systems......Page 108
4.2.1 Voltage Measurement......Page 109
4.2.1.2 Coordinate Transformation......Page 110
4.2.1.3 Fourier Analysis......Page 111
4.2.1.4 The Measurement of Squared Voltage......Page 112
4.2.2.1 Addition......Page 113
4.2.2.3 The Fourier Analysis-Based Measurement System......Page 116
4.2.2.6 Filtering Requirement......Page 119
4.2.3 Current Measurement......Page 121
4.2.4 Power Measurement......Page 124
4.2.5 The Requirements of Measurement Systems......Page 125
4.3.1 The Basic Regulator......Page 127
4.3.2.1 The Basic Single-Phase Oscillator......Page 133
4.3.2.2.2 Equidistant-Pulse Control (Common-Oscillator Control)......Page 135
4.3.3 The Digital Implementation of the Voltage Regulator......Page 136
4.3.3.1 Digital Control......Page 137
4.4 Gate-Pulse Generation......Page 138
4.4.1 The Linearizing Function......Page 139
4.4.2.1 Thyristor Deadtime......Page 140
4.4.2.2 Thyristor Firing-Delay Time......Page 141
4.5 The Synchronizing System......Page 142
4.6.1 The Damping of Electromechanical Oscillations......Page 143
4.6.2 The Susceptance (Reactive-Power) Regulator......Page 144
4.6.3 The Control of Neighboring Var Devices......Page 146
4.6.5 The Secondary-Overvoltage Limiter......Page 147
4.6.8 The Nonlinear Gain and the Gain Supervisor......Page 148
4.7.1.1 SVC Operation within the Control Range......Page 149
4.7.1.2 SVC Operation outside the Control Range......Page 150
4.7.2 Modeling for Small- and Large-Disturbance Studies......Page 151
4.7.5 Modeling for Harmonic-Performance Studies......Page 152
References......Page 153
5.2.1.1.1 Reference Voltage, V_ref......Page 157
5.2.1.1.3 Slope or Current Droop......Page 158
5.2.1.1.4 Overload Range......Page 159
5.2.2 Voltage Control by the SVC......Page 160
5.2.3.1 Reduction of the SVC Rating......Page 162
5.2.3.3 Load Sharing between Parallel-Connected SVCs......Page 163
5.2.4.1 Coupling Transformer Ignored......Page 164
5.2.4.2 Coupling Transformer Considered......Page 166
5.2.4.3 The System Gain......Page 167
5.2.5 Design of the SVC Voltage Regulator......Page 169
5.2.5.1 Simplistic Design Based on System Gain......Page 170
5.2.5.1.1 Item 1......Page 176
5.2.5.1.4 Item 4......Page 177
5.3 Effect of Network Resonances on the Controller Response......Page 178
5.3.2 Sensitivity to Power-System Parameters......Page 181
5.3.2.3 Voltage-Sensitivity Transfer Function......Page 185
5.3.3 Sensitivity to the TCR Operating Point......Page 187
5.3.4 Choice of Transient Gain......Page 190
5.3.5 Certain Features of the SVC Response......Page 191
5.3.6.2 The Nonlinear Gain......Page 192
5.3.6.4 The Gain Supervisor......Page 193
5.3.6.4.2 Level Detector......Page 194
5.3.6.5 Series-Dynamic Compensation......Page 195
5.3.6.6 ac-Side Control Filters......Page 198
5.4.1 Influence of the 2nd Harmonic Voltage on the TCR......Page 201
5.4.2.1 Fault Clearing......Page 206
5.4.2.2 Reactor/Transformer Switching near an SVC......Page 208
5.4.3 TCR Balance Control......Page 210
5.5.1.1 Shunt-Capacitance Resonance......Page 214
5.5.1.3 Shunt-Reactor Resonance......Page 216
5.5.2 SVC Transient Response with Series-Compensated ac Transmission Lines......Page 218
5.5.2.1 Reactor Switching......Page 219
5.5.2.2 Fault Application and Clearing......Page 222
5.5.3 Effect of the Shunt-Reactor Mode on the SVC Voltage Controller......Page 224
5.5.3.2 Filtering of the Shunt-Resonant Mode......Page 226
5.6 3rd Harmonic Distortion......Page 229
5.7.3.1 Impedance-versus-Frequency Computations......Page 232
References......Page 233
6.2 Increase in Steady-State Power-Transfer Capacity......Page 236
6.3 Enhancement of Transient Stability......Page 239
6.3.1 Power-Angle Curves......Page 240
6.3.2 Synchronizing Torque......Page 241
6.3.2.1 Uncompensated System......Page 242
6.3.2.2 SVC-Compensated System......Page 243
6.3.3 Modulation of the SVC Bus Voltage......Page 244
6.4 Augmentation of Power-System Damping......Page 247
6.4.1 Principle of the SVC Auxiliary Control......Page 248
6.4.2.1 Effect of the Power System......Page 250
6.4.2.2.1 SVC Voltage Regulator......Page 251
6.4.2.2.2 SVC PSDC......Page 252
6.4.2.2.4 SVC PSDC......Page 253
6.4.3 Design of an SVC PSDC......Page 254
6.4.3.2 Influence of SVC Sites and the Nature of Loads......Page 255
6.4.3.3 Selection Criteria for PSDC Input Signals......Page 257
6.4.3.5.4 Active Component of the Line Current......Page 258
6.4.3.6.2 Inner-Loop Sensitivity Magnitude......Page 259
6.4.3.7 SVC PSDC Requirements......Page 260
6.4.3.7.1 Performance of Different Signals......Page 262
6.4.3.8 Design Procedure for a PSDC......Page 263
6.4.3.9 Case Study......Page 264
6.4.4.1 Frequency of Remotely Synthesized Voltage......Page 267
6.4.4.2.1 Root-Loci Analysis......Page 269
6.4.4.2.2 Damping-Torque Analysis......Page 270
6.4.5 Alternative Techniques for the Design of SVC Auxiliary Controllers......Page 271
6.5.1 Principles of SVC Control......Page 272
6.5.2 Configuration and Design of the SVC Controller......Page 275
6.5.3 Rating of an SVC......Page 277
6.6.1.1 A Case Study......Page 278
6.6.2 Configuration and Design of the SVC Controller......Page 280
6.6.3 Rating of an SVC......Page 281
6.7 Improvement of HVDC Link Performance......Page 283
6.7.1.3 Support during Recovery from Large Disturbances......Page 284
6.7.2 Configuration and Design of the SVC Controller......Page 286
References......Page 287
7.1.2 The Need for Variable-Series Compensation......Page 292
7.1.3 Advantages of the TCSC......Page 293
7.2 The TCSC Controller......Page 294
7.3.1 Basic Principle......Page 295
7.3.2 Modes of TCSC Operation......Page 296
7.3.2.1 Bypassed-Thyristor Mode......Page 297
7.3.2.3 Partially Conducting Thyristor, or Vernier, Mode......Page 298
7.4 The TSSC......Page 299
7.5 Analysis of the TCSC......Page 300
7.6 Capability Characteristics......Page 305
7.6.1 The Single-Module TCSC......Page 307
7.6.2 The Multimodule TCSC......Page 309
7.7 Harmonic Performance......Page 310
7.8 Losses......Page 313
7.9 Response of the TCSC......Page 316
7.10.1 Variable-Reactance Model......Page 319
7.10.1.1 Transient-Stability Model......Page 320
7.10.1.2 Long-Term-Stability Model......Page 323
7.10.2 An Advanced Transient-Stability Studies Model......Page 324
7.10.2.1 TCSC Controller Optimization and TCSC Response-Time Compensation......Page 325
7.10.4 Modeling for Subsynchronous Resonance (SSR) Studies......Page 326
7.11 Summary......Page 327
References......Page 328
8.2 Open-Loop Control......Page 330
8.3.1 Constant-Current (CC) Control......Page 331
8.3.2 Constant-Angle (CA) Control......Page 332
8.3.4 Constant Power Control......Page 334
8.3.5 Enhanced Power Control......Page 335
8.4 Improvement of the System-Stability Limit......Page 336
8.5 Enhancement of System Damping......Page 337
8.5.1 Principle of Damping......Page 338
8.5.3.2 Remote Signals......Page 340
8.5.4.1 Selection of the Measurement Signal......Page 341
8.5.4.2 Selection of the Synthesizing Impedance......Page 342
8.5.5 H_infinity Method-Based PSDC Design......Page 345
8.6 Subsynchronous Resonance (SSR) Mitigation......Page 349
8.6.1 TCSC Impedance at Subsynchronous Frequencies......Page 350
8.6.2 A Case Study......Page 355
8.6.2.2 Criteria for SSR Mitigation by the TCSC......Page 357
8.7 Voltage-Collapse Prevention......Page 358
8.8 TCSC Installations......Page 360
8.8.1 Imperatriz-Serra da Mesa TCSCs in Brazil......Page 361
8.8.1.1 TCSC Power-Oscillation Damping (POD) Control......Page 363
8.8.1.2 Phasor Estimation......Page 365
8.8.1.3 Performance of Both TCSCs......Page 367
8.8.2 Stode TCSC in Sweden......Page 368
References......Page 370
9.2 Controller Interactions......Page 374
9.2.2 Electromechanical-Oscillation Interactions......Page 375
9.2.5 High-Frequency Interactions......Page 376
9.2.6.1 The Frequency Response of the SVC......Page 377
9.3.1.1 Uncoupled SVC Buses......Page 379
9.3.1.2 Coupled SVC Buses......Page 380
9.3.2.1 Study System......Page 381
9.3.3 The System with Series Compensation......Page 386
9.3.3.1 Shunt-Reactor Resonance......Page 388
9.3.4 High-Frequency Interactions......Page 389
9.3.5.1 Parallel SVCs......Page 394
9.3.5.2 Electrically Close SVCs......Page 395
9.4 SVC-HVDC Interaction......Page 396
9.5 SVC-TCSC Interaction......Page 397
9.5.1 Input Signal of the TCSC-PSDC with Bus Voltage......Page 399
9.5.3 High-Frequency Interactions......Page 402
9.6.1.1 Low-Loop Impedance......Page 408
9.6.2 High-Frequency Interaction......Page 409
9.7 Performance Criteria for Damping-Controller Design......Page 414
9.8.1.1 Derivation of the System Model......Page 416
9.8.1.4 Controller Design and Coordination......Page 417
9.8.2 Controller Coordination for Damping Enhancement......Page 418
9.8.4.1 Techniques without Explicit Robustness Criteria......Page 420
9.8.5 Nonlinear-Constrained Optimization of a Selective-Modal-Performance Index......Page 421
9.8.6 Global Coordination Using Nonlinear-Constrained Optimization......Page 422
9.8.7 Control Coordination Using Genetic Algorithms......Page 423
9.10 Summary......Page 424
References......Page 425
10.2 The STATCOM......Page 428
10.2.1 The Principle of Operation......Page 430
10.2.2 The V-I Characteristic......Page 432
10.2.3 Harmonic Performance......Page 434
10.2.4 Steady-State Model......Page 436
10.2.5.1 A Study System......Page 440
10.2.5.2 STATCOM Performance......Page 441
10.2.6.1 A Multilevel VSC-Based STATCOM......Page 443
10.2.6.3 Capacitor-Voltage Control......Page 446
10.2.6.4 STATCOM Performance......Page 448
10.2.6.4.1 A STATCOM Voltage Controller for Dynamic Compensation......Page 449
10.2.6.4.2 Transient Simulation......Page 450
10.3.1 The Principle of Operation......Page 452
10.3.2 The Control System......Page 455
10.3.3.1 Power-Flow Control......Page 457
10.3.3.2 SSR Mitigation......Page 458
10.4.1 The Principle of Operation......Page 459
10.4.2 Applications......Page 463
10.5 Comparative Evaluation of Different FACTS Controllers......Page 464
10.5.1 Performance Comparison......Page 465
10.5.2 Cost Comparison......Page 467
10.6 Future Direction of FACTS Technology......Page 468
10.6.2 Control-Design Issues......Page 470
10.7 Summary......Page 471
References......Page 472
A.1 Study System......Page 477
A.2 Method of System Gain......Page 479
A.3 Eigenvalue Analysis......Page 480
A.3.1 Step Response......Page 481
A.3.2 Power-Transfer Studies......Page 486
A.4.1 Step-Response Studies......Page 487
A.4.2 Power-Transfer Limits......Page 489
A.5 A Comparison of Physical Simulator Results with Analytical and Digital Simulator Results Using Linearized Models......Page 490
References......Page 492
Appendix B: Transient-Stability Enhancement in a Midpoint SVC-Compensated SMIB System......Page 493
C.1 Introduction......Page 496
C.2 Modal Analysis of the ith Swing Mode, lambda_i......Page 498
C.2.1 Effect of the Damping Controller......Page 500
C.4 Design of the Damping Controller......Page 501
C.4.2 The Maximum Damping Influence (MDI) Index......Page 502
C.4.3 The Natural Phase Influence (NPI) Index......Page 503
References......Page 504
D.2 Definitions of FACTS Controller Terms......Page 505
Reference......Page 507
E......Page 508
F......Page 509
O......Page 510
S......Page 511
T......Page 515
U......Page 517
V......Page 518