Gaseous Dielectrics (eBook)

Front Cover 1
Gaseous Dielectrics V 4
Copyright Page 5
Table of Contents 8
PREFACE 6
CHAPTER 1: BASIC PHYSICS OF GASEOUS DIELECTRICS 16
Excitation and Ionization Coefficients 16
Discussion 23
Laser-Enhanced Electron Attachment and Its Possible Application for Optical Switching 25
Discussion 32
Galvanooptical Measurement of Photodetachment from Negative Ion Swarms in Oxygen 33
Discussion 41
Electron Collision Cross Sections for C F and N 0 42
Discussion 48
A Macroscopic Model of Electron Swarm Motion in 
49 
Non-Equilibrium Description of Electrons in a Gas Influenced by Space-Time Varying Electric Fields 55
Temperature Dependent Electron Transport and Rate Coefficient Studies for e-Beam-Sustained Diffuse Gas Discharge Switching 62
Time Dependent Conductivity Studies of Electron Thermalisation in Simple Gases 70
CHAPTER 2. BASIC MECHANISMS 76
Breakdown Mechanisms in Electronegative Gases 76
Discussion 95
Predischarge Development in N2 and SF6 at High Gas Pressures 96
Discussion 102
Effect of Temperature on the Uniform Field Breakdown Strength of Electronegative Gases 103
Discussion 111
The Influence of Thermal Ionization on Electrical Breakdown 113
Discussion 118
Contribution to a Unified Theory of the Leader Processes 119
Discussion 131
The Influence of Thermal Ionization on Electrical Breakdown 113
Discussion 118
Contribution to a Unified Theory of the Leader Processes 119
Discussion 131
Mechanism of a Short Gap Breakdown 133
Experimental Investigation of the Streamer to Leader Transition in SF6 Under Negative Polarity 141
Modeling of Leader Branching in Electronegative Gases 149
The Leader Inception Characteristics in Positive Sphere-Plane Air Gaps 155
Velocity Measurements in Mixtures of SF6 and N2 in Non-Uniform Field Gaps Under Positive Impulse Voltage 161
CHAPTER 3: GAS DECOMPOSITION/REACTIONS/TOXICITY 168
Decomposition of SF6 by Arc Discharge and the Determination of the Reaction Product S2 F10 168
Discussion 176
Corona-Induced Decomposition of Dielectric Gases 178
Discussion 187
Investigations of the Toxicological Action of Spark- Decomposed SF6 in Mammalian Cells 189
Discussion 196
Degradation of the Dielectric Properties of SF6 Due to the Presence of Gaseous Impurities Deviations to the "Paschen's Law" at High Pressures for Positive Polarity
Discussion 204
The Influence of Impurities on the Dielectric Strength of SF6 for Positive Polarity The Nature of Initiatory Electrons
Formation and Stability of SF6 and S2 F10 214
SOF4 Production in Spark Breakdown of SF6/O2 Mixtures 220
Assay of SF6 and Spark-Decomposed SF6 for Mutagenic Activity in the CHO/HGPRT Mammalian Cell System 228
CHAPTER 4: DIAGNOSTICS/FIELD PROBES 234
Gas Analysis as a Diagnostic Tool for Gas-Insulated Equipment 234
Discussion 242
On the Possibility of Diagnostics of GCB and GIS by Gas Chromatography 243
Discussion 249
On the Electrostatics of Probe Measurements of Surface Charge Densities 250
Discussion 256
Measurement of Accumulated Charge on Dielectric Surfaces with an Electrostatic Probe 257
Discussion 263
The Effect of Humidity on Space Charge Growth in Short Air Gaps 264
Laser Probing of Air Gaps Under AC Conditions 270
CHAPTER 5. GASES/MIXTURES FOR GIS TRANSFORMERS AND CIRCUIT BREAKERS 278
Predicting the Breakdown Strength of Mixtures from Basic Data 278
Discussion 286
The Dielectric Strength of Dichlorotetrafluoroethane (1,2-C2 CI2 F4) Determined in a Combined Swarm/Breakdown Study 287
Discussion 295
The Influence of Gaseous Admixtures to SF6 on the Corona Stabilized Regime at AC and at Positive Impulse Voltage 296
Discussion 302
Nonuniform Field Corona and Breakdown Characteristics of SF6/Freon Mixtures 304
Discussion 310
Effect of a Trichlorotrifluoroethane Vapor Additive on Dielectric Strength of SF6 Gas 313
Measurement of the Figure of Merit M for Several Perfluorocarbon Gases 319
Breakdown Voltage Measurement of Some Vapor-Mist Dielectrics 326
CHAPTER 6: GASEOUS MEDIA FOR DISCHARGE CHEMISTRY AND ETCHING/CORON 332
Gaseous Media for Plasma Chemistry and Etching 332
Discussion 340
Practical Implications of Dry Plasma Processing 341
Discussion 348
Important Considerations for Optimizing Production Rates in RF Discharge Chemistry 349
Discussion 357
Negative DC Corona Discharge in SF6 for Highly Divergent Fields 358
Discussion 365
Calculation of Corona Onset Voltage with Space Charge Effect 366
DC Corona Control in Coaxial Gas Insulating Systems 371
CHAPTER 7. GAS ENGINEERING FOR PULSED POWER AND SWITCHING 378
Gas Engineering for Pulsed Power and Switching 378
Discussion 388
Penning Ionization Ternary Gas Mixtures for Diffuse Discharge Opening Switches 389
Discussion 395
Gas Mixtures for Spark Gap Closing Switches with Emphasis on Efficiency of Operation 396
Discussion 403
The Influence of Transverse Magnetic Fields on Glow Discharges in He/SF6 Gas Mixtures 404
Discussion 412
Analysis of the Cathode Fall of Glow Discharges in a He/SF6 Gas Mixture 413
Gas Engineering Studies for High Pressure Self-Sustained Diffuse Discharge Closing Switches 419
Diffuse Discharges in High-Pressure Mixtures of c-C4 F8 and He 427
CHAPTER 8. GAS BREAKDOWN UNDER STEEP-FRONTED VOLTAGES 434
Statistical Breakdown Process in SF6 and Breakdown Voltage Calculations 434
Discussion 443
Formative Time Lags in SF6 N2 Mixtures for Different Field Distribution 445
Discussion 451
Voltage-Time Characteristics of Impulse Breakdown in SF6 Gas 453
Discussion 459
Spacer Flashover Time Lags in SF6 Under Fast-Front Impulse Voltages 460
Discussion 466
Breakdown Voltage-Time Characteristics in SF6 Mixtures for a Coaxial Cylinder Gap 467
Effect of Field Divergence on the Lightning Impulse Breakdown of Rod-Plane Gaps in N2/SF6 Mixtures 473
Free Particle Initiated Breakdown of SF6 Under Voltages of Different Time Dependence 479
CHAPTER 9. NEW DEVELOPMENTS IN GAS-INSULATED EQUIPMENT/GAS HANDLING 486
Development of ±500 kV HVDC Gas-Insulated Switchgears 486
Discussion 495
A Manufacturer's Experience in the Cyclic Use of SF6 Gas 498
Discussion 505
Volt-Time Curves of Disconnector-Generated Fast Transients inside GIS 506
Discussion 512
Insulation Characteristics of Separate Cooling Sheet Winding-Type Gas-Insulated Transformer 514
Discussion 520
Recovery Strength of SF6-Insulated Gaps Stressed by Double Lighting Impulse Voltages 522
Conduction Currents in Gas-Insulated Switchgear for Low Level DC Stress 528
Effects of Electrode Surface Roughness on Dark Current and Switching Impulse Breakdown Voltage in Compressed SF6 Gas 535
Mixing Rates and Diffusion of Various Gases and Moisture into SF6 541
CHAPTER 10. GAS/INSULATOR INTERFACE/FLASHOVER 552
Surface Changes Induced by Low Kinetic Energy Products from Corona Discharge on Epoxy Resin in Air 552
Discussion 560
Avalanches Near a Dielectric Spacer in Nitrogen Gas 561
Discussion 567
Measurement of the Temporal Decay of Charges on Insulator Surfaces 568
Discussion 574
Effect of Ribs on Surface Discharge in SF6 Gas 575
Discussion 581
Application of ESCA in GIS Spacer Surface Analysis 582
Discussion 588
Study of the Charge Build-up on Dielectrics Submitted to Corona Discharge and Ageing Effects 589
Influence of 60 Hz AC Charging of Spacers on Subsequent Impulse Flashover in Compressed SF6 595
Surface Flashover of Polyester, Polypropylene, and Teflon Films in Low Pressure SF6 and N2 Media 601
Research on Conductor-Plane Long-Gap Characteristics by Surface Discharge Analogy Model 607
The Surface and Volume Effects of Interactions of Internal Partial Discharges with Solid Dielectrics 613
CHAPTER 11. QUALITY CONTROL IN TESTING GAS-INSULATED APPARATUS 620
Fundamental Knowledge and the Testing of GIS 620
Discussion 628
Flashover Damage Test Procedure for Insulating Materials in Compressed SF6 629
Discussion 635
Strength of Typical GIS Configurations with Special Reference to Composite and Combined Stresses 636
Discussion 643
Limits to Partial Discharge Detection 644
Discussion 651
Broad Band Pulse Detection Studies of Corona and Breakdown in Air, N2, O2, CO2 AND SF6 and SF6 -N2 Mixtures 652
CHAPTER 12: REPORTS OF DISCUSSION GROUPS 658
Group Discussion on New Diagnostic Techniques 658
Group Discussion on Gas-Insulated Transformers and DC GIS 666
Group Discussion on Gas Engineering for Modern Technologies: Input from Basic Data 674
LIST OF PARTICIPANTS 686
PHOTOGRAPHS OF PARTICIPANTS 694
AUTHOR INDEX 700