List of Figures ix
List of Tables xix
About the Authors xxi
Preface xxiii
Acknowledgments xxv
Acronyms xxvii
1 Challenges in Insulation of Transmission Equipment with Climate Change 1
1.1 Classical Theories of Pollution Discharge on Insulators 3
1.2 Insulator Contamination 6
1.3 Insulator Wetting 9
1.4 Characterization Parameters for External Insulation 11
1.5 Pollution Monitoring Technology 15
1.6 Main Content of the Book 17
2 Wetting Behavior of Insulator Contamination at Saturated Humidity 21
2.1 Introduction 21
2.2 Example Arrangement 22
2.3 Results 30
2.4 Impact of Non-soluble Deposit Density (NSDD) and Surface Angle 34
2.5 Summary 38
3 Soluble Salt Dissolution in Contaminated Layers 41
3.1 Introduction 41
3.2 Experimental Arrangement 42
3.3 Results 47
3.4 Relationship Between ESDD and Conductivity 50
3.5 Summary 59
4 Wetting Behavior of Insulator Contamination at Unsaturated Humidity 63
4.1 Introduction 63
4.2 Experimental Arrangement 64
4.3 Results 72
4.4 Relationship Between Humidity, Contamination, and Leakage Current 78
4.5 Summary 85
5 Temperature Differences and Their Effect on Wetting Behavior 89
5.1 Introduction 89
5.2 Experimental Arrangement 90
5.3 Results 96
5.4 Summary 103
6 Characterization of Salt Fog Environments and Its Effect on the Outdoor Insulation 107
6.1 Introduction 107
6.2 ESSC 108
6.3 Results 113
6.4 Comprehensive Model for Predicting Flashover Voltage in the Salt Fog Environments 119
6.5 Summary 124
7 Effect of Hydrophobicity on the Contamination Wetting 127
7.1 Introduction 127
7.2 Experimental Arrangement 128
7.3 Results 132
7.4 Dissolving Characteristics of Soluble Salts at Water Drop and Dry Band 135
7.5 Summary 140
8 Wetting Characteristics of the Hydrophobic Material Surface Through Condensation 143
8.1 Introduction 143
8.2 Experimental Arrangement 144
8.3 Results 150
8.4 Discussion 154
8.5 Summary 158
9 Flashover Characteristics of Hydrophobic Surfaces with Different Wetting Degree 161
9.1 Introduction 161
9.2 Flashover Characteristics with Lower Wetting Degree 162
9.3 Flashover Characteristics with Higher Wetting Degree 170
9.4 Discussion of Surface Flashover with Water Involved 177
9.5 Summary 184
10 Factors Influencing the Hydrophobic Surface Flashover and Their Application 187
10.1 Introduction 187
10.2 Wetting Prerequisite of Flashover on Hydrophobic Surface 187
10.3 Effect of Contamination on Flashover Voltage Under Different Wetting Conditions 190
10.4 Dynamic Behavior of Water Droplets Under Electric Field 192
10.5 Replacement and Maintenance Strategies for Degraded Hydrophobic Insulators 200
10.6 Summary 202
11 Insulator Contamination Monitoring Based on Its Hygroscopicity Under Unsaturated Humidity 205
11.1 Introduction 205
11.2 Development of Online Monitoring Devices 206
11.3 System Application 208
11.4 Algorithms for Real-time Contamination Assessment 210
11.5 Assessment Method of Pollution Degree for Hydrophobic Surface 216
11.6 Summary 222
12 Insulator Contamination Monitoring at Saturated Moisture 225
12.1 Introduction 225
12.2 Test Specimens, Facilities, and Procedure 226
12.3 Experimental Results 229
12.4 Analyses and Discussion 233
12.5 Influence of Partial Electric Arc on the Contamination Monitoring in View of Leakage Current 236
12.6 Summary 240
13 Spatial and Temporal Analysis of Contamination on Insulator Surfaces 243
13.1 Introduction 243
13.2 Artificial Contamination Test 244
13.3 Contamination Components of Actual Operating Insulators 249
13.4 Summary 257
14 Correction Methods for Soluble Salt Components in Contamination Assessment 261
14.1 Introduction 261
14.2 Analysis of Surface Conductivity for Soluble Salt Detection 262
14.3 Correction Method for Soluble Salt Components and Equipment 268
14.4 Experimental Validation of Correction Methods 272
14.5 Engineering Implications 275
14.6 Summary 277
Index 281
