About the Author xi
Preface xiii
Acknowledgements xv
1 Introduction 1
1.1 Background 1
1.2 State of the Art of PP Modification Method 6
1.2.1 Nanocomposites 6
1.2.2 Polymer Blending 9
1.2.3 Chemical Copolymerization and Grafting 10
1.2.4 Crystallization Regulation 11
1.3 Effect of Microstructures on Dielectric Properties 13
1.3.1 Effect of Molecular Chain Structures 13
1.3.2 Effect of Aggregate Structures 15
1.4 Effect of Operating Conditions on Dielectric Properties 17
1.4.1 Effect of Aging Treatment 17
1.4.2 Effect of Thermal Stress 18
1.4.3 Effect of Voltage Stress 18
1.5 Content of This Book 19
References 21
Part I Polypropylene Insulation for HVDC Cables 29
2 Space Charge and Dielectric Breakdown 31
2.1 Introduction 31
2.2 Effect of Elastomer on Space Charge and Breakdown Characteristics 32
2.3 Effect of Inorganic Nanofiller on Space Charge and Dielectric Breakdown 45
2.3.1 Metal Oxide Nanoparticles 45
2.3.2 Nanoplatelets 52
2.4 Effect of Organic Compounds on Space Charge and Dielectric Breakdown 64
2.4.1 Introduction 64
2.4.2 Voltage Stabilizer 64
2.4.3 Antioxidant Additives 80
2.5 Conclusion and Outlook 92
References 92
3 Electrical Treeing Phenomenon 103
3.1 Introduction 103
3.2 Electrical Treeing Under Impulse Superimposed on DC Voltage 105
3.2.1 Effects of Impulse Amplitude 106
3.2.2 Effects of Impulse Frequency 111
3.2.3 Effects of DC Voltage Amplitude 112
3.3 Effect of Ambient Temperature on Electrical Treeing 120
3.3.1 Effect of Low Temperature 120
3.3.2 Effect of Operating Temperature 129
3.4 Effect of Bending Deformation on Electrical Treeing 141
3.4.1 Effect of Bending Deformation 141
3.4.2 Effect of Elastic Phase 148
3.5 Methods for Suppressing Electrical Treeing 154
3.5.1 Effect of the Type of Voltage Stabilizer 157
3.5.2 Effect of the Content of Voltage Stabilizer 160
3.6 Conclusion and Outlook 165
References 166
4 Insulation Thickness Optimization for HVDC Cables 173
4.1 Introduction 173
4.1.1 Development of Insulation Thickness of HVDC Cables 173
4.1.2 Advantages of Insulation Thinning 174
4.2 Electric Field Distribution Calculation Model for HVDC Cables 174
4.2.1 Classical Electromagnetic Theoretical Model 174
4.2.2 Bipolar Electronicâ"Ionic Charge Transport Model 178
4.2.2.1 Charge Generation 179
4.2.2.2 Charge Transport 179
4.2.2.3 Charge Recombination 182
4.2.2.4 Charge Extraction 182
4.3 Space Charge and Electric Field Under DC Voltage 182
4.4 Space Charge and Electric Field Under Polarity Reversal Voltage 187
4.4.1 Effect of Temperature Gradients 188
4.4.2 Effect of Polarity Reversal Periods 194
4.5 Insulation Thickness Optimization for HVDC Cables 198
4.5.1 Theoretical Design and Verification of Insulation Thickness of dc Cable 198
4.5.1.1 Design Method of Insulation Thickness of HVDC Cables 199
4.5.1.2 Analysis and Calculation of Insulation Thickness of HVDC Cables 200
4.5.1.3 Verification of Insulation Thickness of DC Cable 203
4.5.2 Insulation Thickness Optimization Based on Modified BEICT Model 207
4.6 Conclusions 214
References 214
Part II Polypropylene Insulation for HVAC Cables 219
5 Polarization and Dielectric Relaxation 221
5.1 Introduction 221
5.2 Effect of Blending Modification 225
5.2.1 FDS of PP Blend Insulation 225
5.2.2 Effect on Dipole Orientational Polarization 228
5.2.3 Effect on Carrier Hopping Polarization 230
5.3 Effect of Monomer Grafting 233
5.3.1 FDS of Grafting PP Insulation 238
5.3.2 Effect on Dipole Orientational Polarization 240
5.3.3 Effect on Carrier Hopping Polarization 242
5.4 Effect of Thermal Ageing 245
5.4.1 FDS of Thermal-Aged PP Insulation 245
5.4.2 Effect on Dipole Orientational Polarization 247
5.4.3 Effect on Carrier Hopping Polarization 249
5.5 Conclusion and Outlook 252
References 252
6 AC Electrical Treeing and Dielectric Breakdown 257
6.1 Introduction 257
6.2 Electrical Treeing Dependent on Crystalline Morphology 260
6.2.1 Crystalline Morphology 260
6.2.2 Effect on Electrical Tree 263
6.2.3 Effect on AC Breakdown 269
6.3 An Insight into Electrical Tree Growth Within Heterogeneous Crystalline Structure 273
6.3.1 Mechanism of Heterogeneous Crystalline Structure 273
6.3.2 Heterogeneous Crystalline Structure Modulation Enhancing Dielectric Strength 281
6.3.3 Electric Field Simulation of Heterogeneous Crystalline Structure 291
6.3.3.1 Heterogeneous Mesoscopic Structure Simulation 291
6.3.3.2 Electric Field Simulation in Mesoscopic Structure 294
6.4 Methods for Suppressing Electrical Treeing 297
6.4.1 Effect of Nucleating Agent and Cooling Rate on Dielectric Property of PP/POE 297
6.4.2 Enhanced Dielectric Breakdown Property of Polypropylene Based on Mesoscopic Structure Modulation by Crystal Phase Transformation 310
6.5 Conclusions 325
References 327
7 Electrothermal Aging and Lifetime Modeling 333
7.1 Introduction 333
7.2 Aging Mechanism and Lifetime Models 334
7.2.1 Physical Lifetime Models 334
7.2.1.1 Thermodynamic Models 335
7.2.1.2 Space-Charge-Based Models 338
7.2.1.3 PD-Induced Damage Model 341
7.2.2 Phenomenological Lifetime Models 343
7.2.2.1 Accelerated Life Tests Under Constant Stress 343
7.2.2.2 Accelerated Life Tests Under Step Stress 344
7.2.2.3 Single-Stress Electrical Lifetime Models 345
7.2.2.4 Single-Stress Thermal Lifetime Models 347
7.2.2.5 Combined Electrothermal Lifetime Models 349
7.3 Thermal Aging 352
7.3.1 Effect on Physicalâ"Chemical Properties 352
7.3.1.1 FT-IR Test 352
7.3.1.2 XRD Test 353
7.3.1.3 DSC Test 354
7.3.1.4 SEM Test 355
7.3.2 Effect on Mechanical and Electrical Properties 355
7.3.2.1 Mechanical Test 355
7.3.2.2 Conductivity Test 357
7.3.2.3 FDS Test 358
7.3.2.4 AC Breakdown Test 359
7.3.3 Lifetime Prediction Under Thermal Stress 360
7.3.3.1 Lifetime prediction model 360
7.3.3.2 Validation of Prediction Model 362
7.4 Electricalâ"Thermal Aging 363
7.4.1 Breakdown Under Electricalâ"Thermal Stress 363
7.4.2 Lifetime Models and Prediction 367
7.5 Conclusions 370
References 371
Index 375
