Contents Part I Fundamentals and Applications of Q{t) Method 1 Classification of Charge Accumulation Measurement 3 1.1 The Progress of Space Charge Measurement Technology 3 1.2 Q(t) Method Can Measure Charges in All Trap Levels 6 1.3 PEA Method is Difficult to Measure Shallow Trapped Charge 7 1.4 Explanation of Current Terms 9 Appendix 1.1 Pico-ammeter Measurement 12 Appendix 1.2 Precautions for Guard Ring Electrode and Pair Diode 13 Appendix 1.3 Noise Comparison Between pA Method and Q(t) Method 15 Appendix 1.4 Measurement of Electric Field Intensity E(0,t) at Electrode Surface 17 References 18 2 Fundamentals of Q(t) Measurement 21 2.1 Q(t) Meter Circuit Configuration 21 2.2 Q{t) Meter Measurement on High Voltage Side 22 2.3 Selection of Capacitance of Integration Capacitor 26 2.4 Stability of Q(t) System 26 2.5 Consideration of Stray Capacitance 29 2.6 Q(t) Method Applied Under High Temperature and High Voltage 31 Reference 33 3 Evaluation of Charge Accumulation 35 3.1 Evaluation of Charge Accumulation by Charge Ratio Q(t)/Qo 35 3.2 Relationship Between Relaxation Time t and Measurement Time tm 39 3.3 Space Charge Formation and Q(t) Simulation 46 3.4 Combination of PEA Measurement and Q{t) Measurement 51 References 55 4 Q(t) Data of Various Polymer Materials 57 4.1 Q(t) Characteristics of Various Polymers .57 4.2 Classification of Charge Accumulation Characteristics 57 4.3 Charge Accumulation Characteristics and Molecular Structure 58 4.4 Relationship Between Charge Accumulation and Electrostatic Potential Distribution in Molecule 67 4.5 Improvement of Charge Accumulation Characteristics of XLPE + Voltage Stabilizer 68 Reference 72 5 Charge Accumulation in Inorganic Materials 73 5.1 Q(t) Data of Inorganic Materials 73 5.2 Electric Field Dependence and Temperature Dependence 75 5.3 DC Permittivity 78 5.4 Comparison of Q(t) Data Between Polymer Insulating Materials and Inorganic Materials 80 5.5 Multilayer Ceramic Capacitors 80 5.6 Research Subjects 86 Reference 93 6 Application to Insulation Diagnosis 95 6.1 Charge Accumulation Evaluation by Q(t) Method on High Voltage Side 95 6.2 Coaxial Cable with Temperature Rise 100 6.3 Charge Accumulation Characteristics of DC-XLPE Cable 103 6.4 Insulation Diagnosis After Gamma Irradiation .......104 6.5 Diagnosis of CV Cable After Accelerated Water-Tree Deterioration 106 6.6 Q(t) Measurement is Strongly Against External Noise 110 6.7 Double-Layer Dielectric Interface 115 6.8 Evaluation of Charge Accumulation in Power Devices 117 6.9 Electrical Tree 121 6.10 Measurement of Two-Dimensional Current Distribution 126 6.11 Q(t) Measurement of Enameled Wire Insulation 127 References 130 Part II Fundamentals and Application of Pulsed Electro-Acoustic Method 7 DC Insulation and Space Charge Accumulation 133 7.1 Measurement of Space Charge Distribution by PEA Method 133 7.2 DC Insulation and AC Insulation 135 7.3 Accumulated Charge and Internal Electric Field 136 7.4 Dielectric Deterioration and Breakdown Caused by Accumulated Electric Charge 139 References 141 8 PEA Method: Pulsed Electro-Acoustic Method 143 8.1 Pulse Pressure Wave of PEA Method 143 8.2 Signal Processing 146 9 Generation of Pulse Pressure Wave 153 9.1 Generation of Pulse Pressure Wave from Electrode Induced Charge 153 9.2 Generation of Pressure Wave from Space Charge 155 9.3 Generation of Pressure Wave from Polarized Charge 158 10 Basics of Electrodynamics and Elastic Mechanics 161 10.1 Basic Piezoelectric Formula 161 10.2 Local Hooke’s Law and Dynamic Hooke’s Law 164 10.3 Explanation of Convolution Integral 164 10.4 Expansion of Dielectric Material Under Applied Electric Fields-Force Acting on Polarized Charge 169 10.5 Fourier Transform 171 10.6 Gaussian Filter 174 10.7 Charged Elastic Body 176 Reference 177 Examples of PEA Measurement Results 179 11.1 Accumulation of Homo and Hetero Charges 179 11.2 Frequency Dependence of Space Charge Accumulation 180 11.3 Charge Accumulation in a Double-Layer Dielectric 182 11.4 Effect of MgO Addition for Blocking Space Charge 185 11.5 Charge Accumulation Inside Coaxial Cables 187 11.6 Distribution of Accumulated Charge in the Cross Section of the Coaxial Cable 189 11.7 Space Charge Measurement of Long Cables 190 11.8 Light Irradiation and Space Charge Formation 192 11.9 Electron Beam Irradiation and Space Charge Formation 193 11.10 Gamma Irradiation and Space Charge Formation 195 11.11 Proton Irradiation and Space Charge Formation 196 11.12 Comparison of Paraelectric and Ferroelectric PEA Signals 198 11.3 3D Measurement Results of Charge Distribution 201 11.14 Generation and Recovery of Attenuation and Dispersion of Pressure Wave 202 References 212 Part Ⅲ Utilization of Quantum Chemical Calculation Analysis 12 Basics of Quantum Chemical Calculation 217 12.1 Terms in the Electron Energy Level Diagram 217 12.2 Atomic and Molecular Orbitals 219 12.3 Diagram of Electron Energy Level 222 12.4 Mulliken Atomic Charges and Electrostatic Potential Distribution 224 12.5 Chemical Structure and Shape of Molecular Orbitals 227 12.6 Positive Polarity and Negative Polarity of Electron Affinity 228 12.7 Application of Fermi-Dirac Distribution Function 230 12.8 Observation of Macromolecules by Molecular Dynamics and Density Functional Calculations 237 References 241 13 Application Examples of Quantum Chemical Calculation 243 13.1 Molecular Chain Approaching and Trap Site Formation 243 13.2 Polymerization of Monomers and Polymers 249 13.3 Chemical Structure and Formation of Trap Sites for Charge 256 13.4 Formation of Trap Sites in Macromolecular Systems (PE and PEN) 259 13.5 Hopping Transfer of Charge 268 13.6 Dominant Current Law 274 13.7 Scope of Application of Classical Theory and Quantum Theory 278 13.8 Electric Field Application and Band Gap 282 13.9 Polarization and Charge Transfer Under Electric Field Application 284 13.10 Summary 294 14 Analysis Examples by Quantum Chemical Calculation 295 14.1 Analysis of Charge Accumulation in PE 295 14.2 Analysis of Charge Accumulation in PET 301 14.3 Analysis of PI Charge Accumulation 307 14.4 Charge Accumulation Characteristics of PEN 313 14.5 Induced Trap Site of MgO and Fullerene Under Applied Electric Fields 318 14.6 Analysis of Positive and Negative Charge Accumulation inETFE 325 14.7 Relationship Between the Needed Inception Voltage of Electrical Tree and Additives 333 14.8 MD Simulation and DF Analysis of the Mixture of PE and AO 336 14.9 Mixture of PE and Surfactant 340 14.10 Molecular Dynamics Simulation of Oxidized EPDM Dispersion 345 14.11 Molecular Dynamics Simulation of PE+H2O+GMS 350 14.12 Curing Agent Effect on Charge Accumulation of Epoxy Resin 353 References 359 Postscript 361
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