Advances in High Voltage Engineering

Contents......Page 6
Contributors......Page 18
Introduction......Page 20
1.1.1 Beginnings......Page 22
1.1.2 Basic breakdown processes......Page 23
1.2 Physical mechanisms......Page 24
1.2.1 Avalanche development......Page 25
1.2.2 Avalanche properties......Page 27
1.2.3 The critical avalanche and the critical volume......Page 29
1.2.4 Streamer formation......Page 31
1.2.5 Streamer development......Page 33
1.2.6 Corona......Page 34
1.2.7 The streamer trail......Page 35
1.2.8 The leader......Page 36
1.2.9 Negative discharges......Page 41
1.3 Applications......Page 42
1.3.1 Sparkover under lightning impulse voltage......Page 43
1.3.2 Sparkover under slow front impulse voltage......Page 45
1.3.3 The influence of field configurations: the gap factor......Page 46
1.3.4 Atmospheric effects......Page 49
1.3.5 Corona at low air density......Page 51
1.3.6 Sparkover over insulator surfaces......Page 52
1.5 References......Page 53
2.1 Introduction......Page 58
2.2 Ionisation phenomena in SF6......Page 59
2.3 Breakdown mechanisms in low divergence fields......Page 61
2.3.1 Streamer breakdown......Page 62
2.3.2 Quasi-uniform fields (coaxial cylinders)......Page 63
2.3.3 Effect of surface roughness......Page 64
2.4 Non-uniform field breakdown in SF6......Page 66
2.4.1 Corona stabilised breakdown......Page 67
2.4.2 Leader breakdown......Page 68
2.5 Breakdown in GIS......Page 69
2.5.1 Streamer-controlled breakdown......Page 70
2.5.2 Leader breakdown......Page 71
2.6.1 Use of additives or gas mixtures......Page 72
2.7 Partial discharge diagnostic techniques for GIS......Page 73
2.7.1 Introduction......Page 75
2.7.2 The range of diagnostic techniques for PD detection......Page 77
2.7.3 Comparison of the techniques......Page 79
2.8.1 Introduction to UHF theory......Page 80
2.8.4 Extraction......Page 81
2.8.5 Waveguide modes and UHF propagation......Page 82
2.8.6 Attenuation of UHF signals......Page 85
2.9.1 Design and testing of UHF couplers......Page 86
2.9.2 Design of a PDM system for GIS......Page 90
2.9.3 Display and interpretation of PD data......Page 91
2.9.4 AI diagnostic techniques......Page 93
2.9.5 Service experience......Page 94
2.10 References......Page 95
3.1 From Franklin to Schonland......Page 98
3.2.2 Incidence......Page 100
3.2.4 Flash components......Page 103
3.2.5 Peak current......Page 104
3.2.6 Current shape......Page 105
3.2.7 Electric fields......Page 106
3.2.8 Spatial development......Page 108
3.3.1 Long sparks in the laboratory......Page 109
3.3.2 Lightning leader propagation......Page 118
3.4.1 Striking distance......Page 121
3.4.2 Geometric models and lightning standards......Page 122
3.4.3 Electrogeometric models......Page 123
3.4.4 Generic models......Page 128
3.4.5 Positive lightning......Page 135
3.5.1 Risk assessment......Page 137
3.5.2 Standard procedure for the calculation of risk factor......Page 139
3.5.3 Electrogeometric calculation of risk factor......Page 140
3.5.4 Generic modelling of risk factor for a negative flash......Page 141
3.5.5 Protection of overhead power lines......Page 146
3.5.6 Protection of electronic equipment......Page 147
3.5.7 Strikes to aircraft and space vehicles......Page 149
3.7 References......Page 151
4.2 Partial discharge degradation mechanisms......Page 160
4.2.1 Particle impact stress......Page 161
4.2.2 Thermal stress......Page 164
4.2.3 Mechanical stress......Page 165
4.2.4 Chemical stress......Page 166
4.2.6 Synergetic interaction of stresses......Page 170
4.3.1 Electrical detection......Page 171
4.3.2 Acoustic detection......Page 188
4.3.4 Chemical detection......Page 191
4.3.5 Comparison among different PD measurement techniques relative to type of plant under investigation......Page 198
4.3.6 Other items of plant......Page 200
4.4 Concluding remarks......Page 204
4.5 Note......Page 205
4.6 References......Page 206
5.1 Introduction......Page 212
5.2.2 Valve-type arresters......Page 213
5.2.4 Metal oxide surge arresters......Page 214
5.2.5 Existing applications of ZnO surge arresters......Page 215
5.3.2 Fabrication process......Page 216
5.3.3 Microstructure......Page 218
5.3.4 Conduction mechanism in ZnO varistors......Page 220
5.4.2 Heat dissipation capability and thermal stability of ZnO surge arresters......Page 222
5.4.3 Thermal runaway......Page 225
5.4.4 Thermal runaway critical condition......Page 226
5.4.6 Simulation of thermal characteristics of ZnO surge arresters......Page 227
5.5.1 Differences between degradation and thermal runaway......Page 228
5.5.2 Factors affecting rate of degradation......Page 229
5.5.3 Destruction mechanism......Page 231
5.6.1 Long term accelerated ageing tests......Page 233
5.6.2 DakinŒArrhenius plots of life span......Page 235
5.7.1 Prebreakdown regime of conduction: AC and DC tests......Page 236
5.7.2 Breakdown regime of conduction and up-turn region: impulse tests......Page 237
5.7.3 Voltage distribution along arrester columns......Page 238
5.8.2 Frequency response of ZnO material......Page 242
5.8.3 Impulse response......Page 245
5.8.4 Combined stress response......Page 246
5.8.5 Equivalent circuit of ZnO material......Page 251
5.9 Monitoring of ZnO surge arresters......Page 254
5.10.1 Standard definitions of important parameters......Page 255
5.10.2 Classification of ZnO surge arresters......Page 257
5.10.3 Other important arrester characteristics......Page 258
5.10.5 Recommended arrester identification......Page 259
5.11 Selection of gapless metal oxide surge arresters......Page 260
5.12.2 Calculation of separation distance......Page 263
5.12.3 Calculation of arrester protective zones......Page 264
5.14 References......Page 265
6.1 Introduction......Page 278
6.2 Role of insulators......Page 279
6.3 Material properties......Page 280
6.4 Examples of design......Page 281
6.4.1 Cap and pin insulators......Page 282
6.4.3 Posts......Page 289
6.4.4 Barrels......Page 292
6.5.1 Surface wettability......Page 293
6.5.2 Hydrophilic case......Page 295
6.5.4 Ice and snow conditions......Page 299
6.6 Electrical characteristics......Page 300
6.6.1 Performance under natural pollution......Page 301
6.6.2 Performance under artificial pollution......Page 304
6.6.3 Interrupter head porcelains......Page 309
6.6.5 Transient overvoltages......Page 310
6.6.6 Iced insulator......Page 312
6.7 Selection and dimensioning......Page 313
6.8.1 Booster sheds......Page 317
6.8.2 Shed extender......Page 318
6.8.4 Coatings......Page 319
6.9.1 Cold switch-on and thermal lag......Page 321
6.9.3 Live line working......Page 322
6.9.5 Electric field distributions......Page 323
6.9.8 Financial and related matters......Page 324
6.10 References......Page 325
7.1 Introduction......Page 330
7.2 System overvoltages......Page 332
7.2.1 External overvoltages......Page 333
7.2.2 Internal overvoltages......Page 335
7.3.1 Transmission lines......Page 339
7.3.3 Circuit breakers......Page 347
7.4 Computed switching overvoltages......Page 348
7.5 Insulation coordination......Page 354
7.5.1 Analytical expressions for F(U) and P(U)......Page 357
7.5.3 Simplified method......Page 359
7.5.4 Withstand voltage......Page 360
7.6 Compact transmission lines......Page 361
7.6.3 Comparison between compact and conventional network......Page 362
7.8 Note......Page 365
7.9 References......Page 366
8.1 Introduction......Page 370
8.2.1 Transmission system......Page 372
8.2.2 Distribution system......Page 373
8.2.3 Methods of system earthing-treatment of neutral......Page 556
8.3.2 Resistivity data of soils and rocks......Page 376
8.3.3 Site investigation and measurement techniques of earth resistivity and structure......Page 378
8.4.1 Standards recommendations......Page 386
8.4.2 Earth impedance......Page 388
8.4.3 Interactions between fault currents and earthing systems......Page 391
8.4.4 Measurement of earth impedance and potentials......Page 393
8.4.5 Maintenance and integrity testing of earthing systems......Page 398
8.4.6 Special installations......Page 400
8.5.1 Step and touch potentials......Page 401
8.5.2 Computation of tolerable voltages......Page 405
8.5.3 Methods for limiting hazardous potential differences and dimensioning of earthing systems......Page 410
8.5.4 Risk management approach to earthing safety......Page 412
8.6.1 Standard guidelines for transient earthing......Page 415
8.6.2 Soil ionisation......Page 416
8.6.4 Models of earthing systems under high frequency and transient conditions......Page 419
8.6.5 Simulations of earthing system performance under transient and high frequency conditions......Page 421
8.7 References......Page 423
9.1 Introduction......Page 436
9.2 Circuit interruption characteristics, arc control and extinction......Page 443
9.2.1 Principles of current interruption in HV systems......Page 448
9.3 Distribution switchgear systems......Page 449
9.4.1 Substation layouts......Page 450
9.4.2 Intelligent networks......Page 455
9.5 Substation control in the system control (CIGRE. WG.39.01)......Page 462
9.6.1 Background......Page 466
9.6.2 Specification of controlled switching installations......Page 467
9.6.3 Concluding remarks......Page 468
9.8.1 SF6 live-tank and dead-tank switchgear......Page 469
9.9.1 Evaluation of solid/gaseous dielectric systems for use in HV switchgear......Page 472
9.9.2 Open market: revised optimal network structure......Page 475
9.9.3 Condition monitoring strategies......Page 477
9.9.4 General discussion......Page 491
9.10 Summary......Page 494
9.12 References......Page 495
10.1.2 Voltage ratings......Page 498
10.1.4 AC and DC......Page 500
10.1.5 Cable types......Page 501
10.2.1 Conductor......Page 502
10.2.3 Insulation......Page 505
10.2.4 Metal sheath......Page 508
10.3.1 Stages of cable manufacture......Page 509
10.3.2 Methods of core manufacture......Page 510
10.4 Failure processes......Page 512
10.4.1 Extrinsic defects......Page 513
10.4.2 Wet ageing - water trees......Page 517
10.4.3 Dry ageing - thermoelectric ageing......Page 519
10.5 Mathematical design models for cables......Page 521
10.6.1 Economics......Page 524
10.7.2 Type approval testing......Page 526
10.7.5 Future trends in testing......Page 527
10.9 References......Page 528
11.1 Introduction......Page 532
11.2.1 The finite-difference method......Page 533
11.2.3 The boundary-element method......Page 534
11.3.1 General......Page 536
11.3.3 The energy functional illustrated......Page 538
11.3.4 Numerical representation......Page 539
11.4.2 Representation of foils......Page 540
11.4.4 Modelling resistive/capacitive systems......Page 542
11.4.5 Modelling partially conducting tapes and paints......Page 543
11.4.6 Space charge modelling......Page 544
11.4.8 Open boundary problems......Page 545
11.5.3 Foils in high voltage bushings......Page 546
11.5.4 Modelling the effect of contamination on an insulating system......Page 548
11.5.5 Stress grading of high voltage windings......Page 551
11.6.1 General......Page 557
11.6.3 Higher-order elements......Page 559
11.7.2 Mathematical singularities......Page 560
11.8.2 Description of the problem geometry......Page 561
11.8.5 Post processor developments......Page 562
11.10 References......Page 563
12.1 Introduction......Page 566
12.2.3 Spectroscopy......Page 568
12.2.4 Light scattering......Page 572
12.2.5 Optical fibre propagation......Page 578
12.3.1 High speed imaging......Page 581
12.3.2 Spectrometer systems......Page 582
12.3.3 Light scattering systems......Page 585
12.3.4 Optical fibre sensing systems......Page 587
12.4.2 Spectroscopic results......Page 596
12.4.3 Coherent scattering results......Page 598
12.4.4 Incoherent scattering results......Page 599
12.4.5 Optical fibre transducer results......Page 601
12.5 Conclusions......Page 606
12.7 Note......Page 608
12.8 References......Page 609
13.1 Introduction......Page 612
13.2.1 Capacitive discharge......Page 615
13.2.2 Charging supplies......Page 616
13.2.3 Capacitors......Page 617
13.2.4 Voltage multiplication: the Marx bank......Page 618
13.2.6 Pulse compression......Page 619
13.2.7 The Melville line Πmagnetic pulse compressor......Page 620
13.2.9 Charge lines......Page 621
13.2.11 Inductive voltage adders......Page 623
13.2.12 Inductive energy storage......Page 625
13.3.1 Introduction......Page 626
13.3.2 Thyristor......Page 627
13.3.3 Bipolar transistor avalanche mode switching......Page 628
13.3.5 MOSFET switching stacks......Page 629
13.3.6 MOSFETs with inductive coupling......Page 630
13.3.8 Novel semiconductor devices......Page 631
13.3.9 Applications of novel semiconductors......Page 632
13.3.11 Conclusions on semiconductor switching......Page 633
13.4 Non-linear transmission lines......Page 634
13.5.1 Introduction......Page 636
13.5.3 Air treatment and pollution control......Page 637
13.5.5 Biological applications......Page 638
13.5.7 Food processing......Page 639
13.5.9 Mechanical applications of spark discharges......Page 640
13.5.10 Medical applications......Page 641
13.5.11 Ultrawideband and HPM applications......Page 642
13.6 Conclusions......Page 643
13.7 References......Page 644
Index......Page 654