Provides an original, detailed, and practical description of current interruption transients, origins, and the circuits involved, and shows how they can be calculated
Based on a course that has been presented by the author worldwide, this book teaches readers all about interruption transients calculation - showing how they can be calculated using only a hand calculator and Excel. It covers all the current interruption cases that occur on a power system and relates oscillatory circuit (transients) and symmetrical component theory to the practical calculation of current interruption transients as applied to circuit breaker application. The book explains all cases first in theory, and then illustrates them with practical examples.
Topics featured in Current Interruption Transients Calculation, Second Edition include: RLC Circuits; Pole Factor Calculation; Terminal Faults; Short Line Faults; Inductive Load Switching; and Capacitive Load Switching. The book also features numerous appendices that cover: Differential Equations; Principle of Duality; Useful Formulae; Euler’s Formula; Asymmetrical Current-Calculating Areas Under Curves; Shunt Reactor Switching; and Generator Circuit Breaker TRVs.
- Offers a clear explanation of how to calculate transients without the use of specialist software, showing how four basic circuits can represent all transients
- Describes every possible current interruption case that can arise on a power system, explaining them through theory and practical examples
- Analyses oscillatory circuit (transients) and symmetrical component theory in detail
- Takes a practical approach to the subject so engineers can use the knowledge in circuit breaker applications
Current Interruption Transients Calculation, Second Edition is an ideal book for power electrical engineers, as well as transmission and distribution staff in the areas of planning and system studies, switchgear application, specification and testing, and commissioning and system operation.
Table of Contents
Preface to the Second Edition ix
Preface to First Edition xi
1 Introduction 1
1.1 Background 1
1.2 Short-Circuit Rating Basis for High-Voltage Circuit Breakers 2
1.3 Current Interruption Terminology 4
Further Reading 7
2 RLC Circuits 9
2.1 General 9
2.2 Series RLC Circuit with Step Voltage Injection 9
2.3 Source-Free Series RLC Circuit with Precharged Capacitor 15
2.4 Source-Free Parallel RLC Circuit with Precharged Capacitor 18
2.5 Parallel RLC Circuit with Ramp Current Injection 21
2.6 Alternative Equations 27
2.7 Traveling Wave Basics 28
2.8 Summary 34
References 34
Further Reading 34
3 Pole Factor Calculation 35
3.1 General 35
3.2 Pole Factors: Effectively Earthed Systems 44
3.3 Pole Factors: Non-Effectively Earthed Systems 52
3.4 Alternative Pole Factor Calculation Method 56
3.5 Three-Phase Test Circuit Arrangement 59
3.6 Summary 60
Further Reading 61
4 Terminal Faults 63
4.1 General Considerations 63
4.2 Standard TRV Derivation 65
4.3 Effect of Added Capacitance 73
4.4 Effect of Added Resistance 85
4.5 Effect of Series Reactors 88
4.6 Out-of-Phase Switching 96
4.7 Asymmetrical Currents 97
4.8 Double Earth Faults 105
4.9 Summary 108
Further Reading 109
5 Short Line Faults 111
5.1 General 111
5.2 Line Side Voltage Calculation 111
5.3 Effect of Added Capacitance 119
5.4 Discussion 122
Further Reading 123
6 Inductive Load Switching 125
6.1 General 125
6.2 General Shunt Reactor Switching Case 128
6.3 Shunt Reactors with Isolated Neutrals 135
6.4 Shunt Reactors with Neutral Reactor Earthed Neutrals 139
6.5 Shunt Reactors with Earthed Neutrals 140
6.6 Reignitions 141
6.7 Unloaded Transformer Switching 142
6.8 Discussion 143
6.9 Summary 143
Further Reading 146
7 Capacitive Load Switching 147
7.1 General 147
7.2 Shunt Capacitor Banks 147
7.2.1 Energization 147
7.2.1.1 Inrush Current 148
7.2.1.2 Limiting Inrush Current 154
7.2.2 De-Energization 156
7.2.2.1 General Considerations 156
7.2.2.2 Recovery Voltages 156
7.2.2.3 Reignitions and Restrikes 157
7.2.3 Outrush 163
7.3 Transmission Lines 164
7.4 Cables 167
7.5 Special Case: Interrupting Small Capacitance Currents 170
7.6 Summary 173
References 174
Further Reading 174
8 Circuit Breaker Type Testing 175
8.1 Introduction 175
8.2 Circuit Breaker Interrupting Time 175
8.3 Inherent Transient Recovery Voltages 182
8.4 Inductive Load Switching 182
8.5 Capacitive Current Switching 183
Further Reading 183
Appendix A: Differential Equations 185
Appendix B: Principle of Duality 195
Appendix C: Useful Formulae 201
Appendix D: Euler’s Formula 205
Appendix E: Asymmetrical Current-Calculating Areas Under Curves 209
Appendix F: Shunt Reactor Switching - First-Pole-to-Clear Circuit Representation 213
Appendix G: Special Case: Generator Circuit Breakers TRVs 219
Appendix H: Evolution of Transient Recovery Voltages 239
Appendix I: Equation Plotting Using Excel 261
Index 277
