Author Biographies xi
Foreword xiii
Symbols and Abbreviations xv
1 Introduction 1
1.1 Overview 2
1.2 Acknowledgments 3
1.3 Users 3
2 Physical Behavior of Partial Discharges 5
2.1 Introduction 5
2.2 External Discharges 7
2.2.1 Tip with Negative Polarity 10
2.2.2 Tip with Positive Polarity 11
2.3 Internal Discharges 17
2.3.1 Discharges in Liquid Insulation 17
2.3.2 Discharges in Solid Insulation 18
2.4 Gliding Discharges 24
2.5 PD Quantities 24
References 29
3 Modeling of PD Behavior 33
3.1 Introduction 33
3.2 Network-Based Model 33
3.3 Field-Based Model 42
3.3.1 Stages of PD Behavior Modeling for DC Conditions 48
3.3.1.1 Stage 1: Inception of Ionization Processes 48
3.3.1.2 Stage 2: Establishment of an Electrical Dipole 49
3.3.1.3 Stage 3: Dissipation of the Electrical Dipole 49
3.3.2 Extended Modeling Parameters 49
3.3.3 Summary 52
References 53
4 Measurement of Partial Discharges 55
4.1 Introduction 55
4.2 Signal Properties 57
4.2.1 Device Under Test 57
4.2.2 High Voltage Circuit 58
4.3 Coupling Methods 59
4.3.1 Capacitive Coupling with Measuring Impedance 60
4.3.2 Inductive Coupling with High-Frequency Current Transformer 65
4.4 Signal Processing 68
4.4.1 Full Analog Processing 68
4.4.2 Semi-Digital Processing 68
4.4.3 Full Digital Processing 69
4.5 Measurement Principles 70
4.5.1 Narrow-Band Measurement 72
4.5.2 Wide-Band Measurement 76
4.5.3 Time Domain Integration 79
4.5.4 Radio Interference Voltage (RIV) Measurement 83
4.5.5 Synchronous Measurement for Multichannel Application 84
4.6 Noise Suppression and Reduction 86
4.6.1 Introduction 86
4.6.2 Noise Sources 87
4.6.2.1 Main Sources of Conducted Coupled Noise 87
4.6.2.2 Blocking Impedance and Filters 88
4.6.2.3 Electrodes and Wire 88
4.6.2.4 Coupling Capacitor 88
4.6.2.5 Floating Potential Elements 88
4.6.2.6 Pulse-Shaped and Harmonic Noise 89
4.6.2.7 Noise via Grounding System or Wire Loops 89
4.6.2.8 Mains Plug and Background Noise of the Measurement Instrument 89
4.6.3 Denoising Methods 89
4.6.3.1 Shielding 90
4.6.3.2 Filters 90
4.6.3.3 Balanced Bridge Measurements 90
4.6.3.4 Windowing 92
4.6.3.5 Gating 93
4.6.3.6 Clustering 93
4.7 Visualization and Interpretation of PD Events 96
4.7.1 Introduction 96
4.7.2 Classical Methods 97
4.7.3 Advanced Methods 99
4.7.4 Pulse Sequence Analysis 103
4.8 Artificial Intelligence and Expert Systems 104
4.8.1 Introduction 104
4.8.2 Artificial Intelligence and Artificial Neural Networks 105
4.8.2.1 Learning Process 107
4.8.2.2 ANN Architecture 108
4.8.2.3 Common Principles 108
4.8.2.4 Applications for PD Classification and Localization 110
4.8.2.5 Basic Principles of PD Recognition 110
4.8.3 Expert System 116
4.8.3.1 Introduction 116
4.8.3.2 Application for PD Diagnostic 118
4.9 Calibration 119
4.9.1 Calibration of PD Measuring Circuit 119
4.9.2 Performance Test of PD Calibrators 122
References 124
5 Electromagnetic Methods for PD Detection 129
5.1 Introduction 129
5.2 PD Measurement by HF and VHF Sensors 129
5.2.1 PD Measurement by cc 129
5.2.1.1 Theory 129
5.2.1.2 cc Characteristics and Installation Aspect for PD Measurement 133
5.2.1.3 cc Installation 134
5.2.1.4 cc for PD Measurement 134
5.2.2 PD Measurement by Inductive Couplers 137
5.2.2.1 PD Measurement by High-Frequency Current Transformers 137
5.2.2.2 PD Measurement by Rogowski Coil 141
5.2.3 PD Measurement by DCS 144
5.2.3.1 Theory 144
5.2.3.2 DCS Structure and Characteristic 144
5.2.3.3 Application of DCS for Cable and Joint PD Measurement 146
5.3 PD Measurement by UHF Method 146
5.3.1 Theory 146
5.3.1.1 General Idea 146
5.3.1.2 Propagation and Attenuation of UHF Signal 147
5.3.1.3 UHF Signal Attenuation 150
5.3.2 UHF Sensors 150
5.3.3 UHF PD Measurement System 154
5.3.3.1 Sensitivity Verification for GIS PD Measurement 157
5.3.3.2 Determination of PD Measurement by UHF PD Technique 160
5.3.4 Application of UHF PD Measurement 161
5.3.4.1 PD Detection by UHF in GIS and GIL 161
5.3.4.2 UHF PD Detection in Transformers 161
5.3.4.3 Application of UHF PD Detection to Other High-Voltage Equipment 161
References 164
6 Non-electrical Methods for PD Measurement 167
6.1 Introduction 167
6.2 Optical PD Measurement 167
6.2.1 Theory 167
6.2.2 Principle for Optical PD Measurement Technique 169
6.2.3 Application of Optical PD Measurement 171
6.2.3.1 Insulators, Transformer Bushings, Surge Arrestors, Transmission Lines, and Fittings 171
6.2.3.2 Rotating Machines 172
6.3 Acoustic Emission PD Measurement 172
6.3.1 Theory 172
6.3.2 Acoustic Receivers and Acoustic Sensors 175
6.3.2.1 Hand-Held AE PD Receivers 175
6.3.2.2 Instrument-Based AE PD Detection 177
6.3.3 Acoustic Noises in AE PD Measurement 183
6.3.4 General Idea for AE PD Measurement 184
6.3.4.1 Sensitivity Check for AE PD Measurement 184
6.3.4.2 AE PD Measurement 184
6.3.5 Application of Acoustic PD Measurement for High-Voltage Apparatus 184
6.3.5.1 Detection of Corona and Surface Discharge from Outdoor Insulators or High- Voltage Conductors 184
6.3.5.2 PD Detection in Transformers 185
6.3.5.3 PD Detection by AE PD Measurement Technique in GIS and GIL 185
6.3.5.4 PD Detection in Rotating Machine by AE PD Measurement Technique 187
6.3.5.5 PD Detection for Other High-Voltage Equipment 188
6.4 Chemical Byproducts 188
6.4.1 Theory 188
6.4.2 Dissolved Gas Analysis for Liquid Insulation 188
6.4.2.1 Dissolved Gas Generation in Liquid Insulation 188
6.4.2.2 Application of DGA for PD Analysis 189
6.4.3 Decomposition Gas Analysis 194
6.4.3.1 Decomposition SF 6 Analysis for Gas-Insulated High-Voltage Equipment 194
6.4.4 Ozone Measurement and Analysis for Air-Cooled Hydrogenerators 195
References 195
7 PD Localization 199
7.1 Introduction 199
7.2 The Complexity of PD Localization 199
7.3 Classification of PD Localization 200
7.3.1 PD Localization for the Internal Insulation 200
7.3.2 PD Localization for the External Insulation 200
7.4 PD Localization Techniques for the Internal Insulation 200
7.4.1 Pulse Time Arrival Method 201
7.4.1.1 Concept of Pulse Time Arrival Method 201
7.4.1.2 Application of the Pulse Time Arrival Method for PD Localization in High Voltage Equipment 201
7.4.2 Auscultatory Method 205
7.4.2.1 Concept of Auscultatory Method 205
7.4.2.2 Application of the Auscultatory Method for PD Localization in a Transformer 206
7.4.3 Triangulation Method 206
7.4.3.1 Concept of Triangulation Method 206
7.4.3.2 Application of the Triangulation Method for PD Localization in a Transformer 210
7.4.4 Bouncing Particle Localization Method 216
7.5 PD Localization Techniques for the External Insulation 217
7.5.1 Application of the Corona Camera 217
7.5.2 Application of the Airborne Acoustic Probe 217
References 218
8 PD Measurement Under Direct and Impulse Voltage Stress Conditions 221
8.1 Introduction 221
8.2 PD Measurement at Direct Voltage Conditions 222
8.3 PD Measurement at Impulse Voltage Conditions 229
8.3.1 PD Measurement at Classical Impulse Voltage Conditions 230
8.3.2 PD Measurement at Repetitive Pulse Voltage Conditions 233
References 236
9 Monitoring of PD Behavior 239
9.1 Introduction 239
9.2 PD Monitoring 239
9.2.1 Off-Line and On-Line PD Measurement 240
9.2.1.1 Off-Line PD Monitoring 240
9.2.1.2 On-Line PD Monitoring 242
9.2.2 PD Monitoring System 247
9.2.2.1 PD Sensor 247
9.2.2.2 Data Acquisition 249
9.3 Application of PD Monitoring 254
9.3.1 Application of PD Monitoring for the Existing High-Voltage Equipment 254
9.3.2 Application of PD Monitoring for the New Equipment Supporting Smart Grid 255
9.4 Challenges for PD Monitoring in Future 256
References 258
10 Evaluation of PDs 261
10.1 Introduction 261
10.2 In-House and On-Site PD Testing 262
10.2.1 In-House PD Testing 263
10.2.2 On-Site PD Testing 263
10.3 How to Evaluate PD Test Results 264
10.4 Effect of PD on Insulation Degradation 264
10.5 Integrity of PD Measurement 266
10.6 PD Quantity 267
10.6.1 Discharge Magnitude 267
10.6.2 PDIV, PDEV, and Other PD Quantities 267
10.6.3 PD Quantity as Criteria for Evaluation of Insulation Condition 268
10.7 PD Patterns 270
10.7.1 Analysis of PD Patterns 270
10.7.2 PD Patterns as Criteria for Evaluation of Insulation Condition 271
10.8 PD Signal in Time Domain and Frequency Domain Analysis 275
10.9 PD Source as Criteria for Evaluation of Insulation Condition 280
10.10 Noise Patterns and Noise Reduction 280
10.10.1 Noise Patterns 280
10.10.2 Noise Reduction 281
10.11 Effective Evaluation of PD Phenomena 283
References 284
11 Standards 285
11.1 Standards 285
11.2 Technical Brochures 287
11.3 Books 289
References 289
12 Conclusions and Outlook 291
Index 293
