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EXTRA HIGH VOLTAGE AC TRANSMISSION

by Jntu Heroes
Type: NoteInstitute: JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY Downloads: 186Views: 2137Uploaded: 7 months agoAdd to Favourite

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EXTRA HIGH VOLTAGE AC TRANSMISSION by Jntu Heroes

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Contents Foreword ................................................................................................. vii Preface to the Third Edition .................................................................... ix Preface to the First Edition ...................................................................... xi Chapter 1 1.1 1.2 1.3 Chapter 2 2.1 2.2 2.3 2.4 2.5 2.6 Introduction to EHV AC Transmission .......................................... 1–8 Role of EHV AC Transmission .................................................................. 1 Brief Description of Energy Sources and their Development ..................... 1 Description of Subject Matter of this Book ............................................... 4 smartworlD.asia Transmission Line Trends and Preliminaries ............................. 9–21 Standard Transmission Voltages............................................................... 9 Average Values of Line Parameters ........................................................ 11 Power-Handling Capacity and Line Loss ................................................. 11 Examples of Giant Power Pools and Number of Lines ............................ 14 Costs of Transmission Lines and Equipment .......................................... 15 Mechanical Considerations in Line Performance .................................... 17 Chapter 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Calculation of Line and Ground Parameters ............................. 22–60 Resistance of Conductors ........................................................................ 22 Temperature Rise of Conductors and Current-Carrying Capacity ............ 26 Properties of Bundled Conductors ........................................................... 28 Inductance of EHV Line Configurations .................................................. 30 Line Capacitance Calculation .................................................................. 38 Sequence Inductances and Capacitances ................................................. 41 Line Parameters for Modes of Propagation ............................................. 44 Resistance and Inductance of Ground Return ......................................... 50 Chapter 4 4.1 4.2 Voltage Gradients of Conductors ............................................... 61–112 Electrostatics .......................................................................................... 61 Field of Sphere Gap ................................................................................ 63 1
xiv Contents 4.3 4.4 4.5 4.6 4.7 4.8 4.9 Field of Line Charges and Their Properties ............................................ 68 Charge-Potential Relations for Multi-Conductor lines ............................. 72 Surface Voltage Gradient on Conductors ................................................. 76 Examples of Conductors and Maximum Gradients on Actual Lines ......... 87 Gradient Factors and Their Use ............................................................. 87 Distribution of Voltage Gradient on Sub-conductors of Bundle ................ 89 Design of Cylindrical Cages for Corona Experiments .............................. 92 Appendix: Voltage Gradients on Conductors in the Presence of Ground Wires on Towers .................................................................................. 107 Chapter 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 5.11 Corona Effects—I : Power Loss and Audible Noise ................ 113–137 I2R Loss and Corona Loss ..................................................................... 113 Corona-Loss Formulae ......................................................................... 114 Charge-Voltage (q–V) Diagram and Corona Loss ................................... 118 Attenuation of Travelling Waves Due to Corona Loss ........................... 122 Audible Noise: Generation and Characteristics ..................................... 125 Limits for Audible Noise ....................................................................... 126 AN Measurement and Meters ............................................................... 127 Formulae for Audible Noise and Use in Design .................................... 131 Relation Between Single-Phase and 3-Phase AN Levels ........................ 134 Day-Night Equivalent Noise Level........................................................ 135 Some Examples of AN Levels from EHV Lines ..................................... 136 Chapter 6 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 6.11 Chapter 7 7.1 7.2 7.3 7.4 smartworlD.asia Corona Effects—II : Radio Interference .................................. 138–171 Corona Pulses: Their Generation and Properties.................................. 138 Properties of Pulse Trains and Filter Response .................................... 142 Limits for Radio Interference Fields ..................................................... 144 Frequency Spectrum of the RI Field of Line ......................................... 147 Lateral Profile of RI and Modes of Propagation ..................................... 147 The CIGRE Formula ............................................................................. 151 The RI Excitation Function .................................................................. 156 Measurement of RI, RIV, and Excitation Function ................................ 162 Measurement of Excitation Function .................................................... 164 Design of Filter .................................................................................... 166 Television Interference ......................................................................... 167 Electrostatic and Magnetic Fields of EHV Lines .................... 172–205 Electric Shock and Threshold Currents ................................................ 172 Capacitance of Long Object ................................................................... 173 Calculation of Electrostatic Field of AC Lines ....................................... 174 Effect of High E.S. Field on Humans, Animals, and Plants ................... 183 2
Contents xv 7.5 7.6 7.7 7.8 7.9 7.10 7.11 Meters and Measurement of Electrostatic Fields .................................. 185 Electrostatic Induction in Unenergized Circuit of a D/C Line ................ 186 Induced Voltage in Insulated Ground Wires.......................................... 189 Magnetic Field Effects .......................................................................... 190 Magnetic Field of 3-Phase Lines ........................................................... 191 Magnetic Field of a 6-Phase Line .......................................................... 199 Effect of Power-Frequency Magnetic Fields on Human Health ............. 200 Chapter 8 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 8.10 Theory of Travelling Waves and Standing Waves .................. 206–235 Travelling Waves and Standing Waves at Power Frequency ................. 206 Differential Equations and Solutions for General Case .......................... 209 Standing Waves and Natural Frequencies ............................................ 215 Open-Ended Line: Double-Exponential Response .................................. 219 Open-Ended Line: Response to Sinusoidal Excitation ............................ 220 Line Energization with Trapped-Charge Voltage ................................... 221 Corona Loss and Effective Shunt Conductance ..................................... 223 The Method of Fourier Transforms ...................................................... 224 Reflection and Refraction of Travelling Waves ...................................... 227 Transient Response of Systems with Series and Shunt Lumped Parameters and Distributed Lines ........................................................ 230 Principles of Travelling-Wave Protection of E.H.V. Lines ..................... 232 8.11 Chapter 9 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9 9.10 Chapter 10 10.1 10.2 10.3 10.4 10.5 smartworlD.asia Lightning and Lightning Protection ....................................... 236–258 Lightning Strokes to Lines ................................................................... 236 Lightning-Stroke Mechanism ............................................................... 237 General Principles of the Lightning-Protection Problem ....................... 240 Tower-Footing Resistance ..................................................................... 243 Insulator Flashover and Withstand Voltage .......................................... 245 Probability of Occurrence of Lightning-Stroke Currents ....................... 245 Lightning Arresters and Protective Characteristics .............................. 246 Dynamic Voltage Rise and Arrester Rating ........................................... 250 Operating Characteristics of Lightning Arresters ................................. 251 Insulation Coordination Based on Lightning ......................................... 254 Overvoltages in EHV Systems Caused by Switching Operations .................................................................................. 259–294 Origin of Overvoltages and Their Types................................................ 259 Short-Circuit Current and the Circuit Breaker ..................................... 260 Recovery Voltage and the Circuit Breaker ............................................ 262 Overvoltages Caused by Interruption of Low Inductive Current ........... 264 Interruption of Capacitive Currents ...................................................... 265 3
xvi Contents 10.6 10.7 10.8 10.9 10.10 10.11 10.12 10.13 Ferro-Resonance Overvoltages ............................................................. 266 Calculation of Switching Surges—Single Phase Equivalents ................. 267 Distributed-Parameter Line Energized by Source ................................. 273 Generalized Equations for Single-Phase Representation ....................... 276 Generalized Equations for Three-Phase Systems .................................. 280 Inverse Fourier Transform for the General Case .................................. 285 Reduction of Switching Surges on EHV Systems ................................... 287 Experimental and Calculated Results of Switching-Surge Studies ......... 289 Chapter 11 11.1 11.2 11.3 11.4 11.5 11.6 11.7 Insulation Characteristics of Long Air Gaps ......................... 295–317 Types of Electrode Geometries Used in EHV Systems .......................... 295 Breakdown Characteristics of Long Air Gaps ........................................ 296 Breakdown Mechanisms of Short and Long Air Gaps ............................ 299 Breakdown Models of Long Gaps with Non-uniform Fields ................... 302 Positive Switching-Surge Flashover—Saturation Problem .................... 305 CFO and Withstand Voltages of Long Air Gaps—Statistical Procedure . 308 CFO Voltage of Long Air Gaps—Paris's Theory .................................... 314 Chapter 12 12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 12.9 Power-Frequency Voltage Control and Overvoltages ............ 318–358 Problems at Power Frequency .............................................................. 318 Generalized Constants .......................................................................... 318 No-Load Voltage Conditions and Charging Current .............................. 321 The Power Circle Diagram and Its Use ................................................. 323 Voltage Control Using Synchronous Condensers .................................. 328 Cascade Connection of Components—Shunt and Series Compensation . 330 Sub-Synchronous Resonance in Series-Capacitor Compensated Lines ... 337 Static Reactive Compensating Systems (Static VAR) ............................. 345 High Phase Order Transmission ........................................................... 355 smartworlD.asia Chapter 13 13.1 13.2 13.3 13.4 EHV Testing and Laboratory Equipment ................................ 359–408 Standard Specifications ......................................................................... 359 Standard Waveshapes for Testing ......................................................... 361 Properties of Double-Exponential Waveshapes ..................................... 363 Procedures for Calculating α ,β, E ........................................................ 366 13.5 13.6 13.7 13.8 13.9 13.10 Waveshaping Circuits: Principles and Theory ....................................... 368 Impulse Generators with Inductance .................................................... 373 Generation of Switching Surges for Transformer Testing ..................... 376 Impulse Voltage Generators: Practical Circuits .................................... 378 Energy of Impulse Generators .............................................................. 381 Generation of Impulse Currents ........................................................... 385 4

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