Fault Location on Transmission and Distribution Lines Principles and Applications

This book provides readers with up-to-date coverage of fault location algorithms in transmission and distribution networks. The algorithms will help readers track down the exact location of a fault in the shortest possible time.  Furthermore, voltage and current waveforms recorded by digital relays, digital fault recorders, and other intelligent electronic devices contain a wealth of information.  Knowledge gained from analysing the fault data can help system operators understand what happened, why it happened and how it can be prevented from happening again.  The book will help readers convert such raw data into useful information and improve power system performance and reliability.

Swagata Das, PhD, is an Application Engineer (Protection) at Schweitzer Engineering Laboratories, Texas, USA. She is an IEEE Senior Member and has published in peer-reviewed journals and presented her research on fault location and fault data analysis in transmission and distribution networks to industry professionals at several IEEE Power and Energy Society conferences.

Surya Santoso, PhD, is a Professor in Electrical Engineering at The University of Texas at Austin, USA. His research interests include power systems fault analytics and protection, power systems modeling and simulation, and power quality. He is an IEEE Fellow and a Distinguished Lecturer for the IEEE Power and Energy Society.

Sundaravaradan N. Ananthan, PhD, is a Project Engineer (Protection) at Schweitzer Engineering Laboratories, Texas, USA. He has a background in power system protection and fault location in transmission and distribution networks and has published his research in many international journals and conferences.

1 Introduction 1

1.1 Power System Faults 1

1.2 What Causes Shunt Faults? 4

1.3 Aim and Importance of Fault Location 18

1.4 Types of Fault-Locating Algorithms 21

1.5 How are Fault-Locating Algorithms Implemented? 25

1.6 Evaluation of Fault-Locating Algorithms 29

1.7 The Best Fault-Locating Algorithm 30

1.8 Summary 30

2 Symmetrical Components 33

2.1 Phasors 34

2.2 Theory of Symmetrical Components 35

2.3 Interconnecting Sequence Networks 37

2.4 Sequence Impedances of Three-Phase Lines 44

2.5 Exercise Problems 50

2.6 Summary 55

3 Fault Location on Transmission Lines 57

3.1 One-Ended Impedance-Based Fault Location Algorithms 57

3.1.1 Simple Reactance Method 60

3.1.2 Takagi Method 62

3.1.3 Modified Takagi Method 63

3.1.4 Current Distribution Factor Method 66

3.2 Two-Ended Impedance-Based Fault Location Algorithms 68

3.2.1 Synchronized Method 68

3.2.2 Unsynchronized Method 69

3.2.3 Unsynchronized Current-Only Method 70

3.2.4 Synchronized Line Current Differential Method 71

3.3 Three-Ended Impedance-Based Fault Location Algorithms 72

3.3.1 Synchronized Method 73

3.3.2 Unsynchronized Method 75

3.3.3 Unsynchronized Current-Only Method 76

3.3.4 Synchronized Line Current Differential Method 77

3.4 Traveling Wave Fault Location Algorithms 78

3.4.1 Single-Ended Traveling Wave Method 81

3.4.2 Double-Ended Traveling Wave Method 81

3.4.3 Error Sources 82

3.5 Exercise Problems 89

3.6 Summary 109

4 Error Sources in Impedance-Based Fault Location 111

4.1 Power System Model 111

4.2 Input Data Errors 113

4.2.1 DC Offset 113

4.2.2 CT Saturation 115

4.2.3 Aging CCVTs 118

4.2.4 Open-Delta VTs 118

4.2.5 Inaccurate Line Length 122

4.2.6 Untransposed Lines 122

4.2.7 Variation in Earth Resistivity 124

4.2.8 Non-Homogeneous Lines 127

4.2.9 Incorrect Fault Type Selection 128

4.3 Application Errors 128

4.3.1 Load 128

4.3.2 Non-Homogeneous System 130

4.3.3 Zero-Sequence Mutual Coupling 134

4.3.4 Series Compensation 140

4.3.5 Three-Terminal Lines 141

4.3.6 Radial Tap 142

4.3.7 Evolving Faults 143

4.4 Exercise Problems 144

4.5 Summary 150

5 Fault Location on Overhead Distribution Feeders 153

5.1 Impedance-Based Methods 160

5.1.1 Loop Reactance Method 161

5.1.2 Simple Reactance Method 167

5.1.3 Takagi Method 168

5.1.4 Modified Takagi Method 168

5.1.5 Girgis et al. Method 168

5.1.6 Santoso et al. Method 170

5.1.7 Novosel et al. Method 172

5.2 Challenges with Distribution Fault Location 173

5.2.1 Load 173

5.2.2 Non-Homogeneous Lines 174

5.2.3 Inaccurate Earth Resistivity 178

5.2.4 Multiple Laterals 178

5.2.5 Best Data for Fault Location: Feeder or Substation Relays 180

5.2.6 Distributed Generation 180

5.2.7 High Impedance Faults 184

5.2.8 CT Saturation 184

5.2.9 Grounding 185

5.2.10 Short Duration Faults 186

5.2.11 Missing Voltage 186

5.3 Exercise Problems 187

5.4 Summary 210

6 Distribution Fault Location With Current Only 211

6.1 Current Phasors Only Method 211

6.2 Current Magnitude Only Method 216

6.3 Short-circuit Fault Current Profile Method 224

6.4 Exercise Problems 226

6.5 Summary 246

7 System and Operational Benefits of Fault Location 247

7.1 Verify Relay Operation 248

7.2 Discover Erroneous Relay Settings 248

7.3 Detect Instrument Transformer Installation Errors 257

7.4 Validate Zero-Sequence Line Impedance 263

7.5 Calculate Fault Resistance 266

7.6 Prove Short-Circuit Model 267

7.7 Adapt Autoreclosing in Hybrid Lines 268

7.8 Detect the Occurrence of Multiple Faults 270

7.9 Identify Impending Failures and Take Corrective Action 274

7.10 Exercise Problems 274

7.11 Summary 284

Appendix A: Fault Location Suite in MATLAB 285

A.1 Understanding the Fault Location Script 285

References

Index

The New copy of this book will include any supplemental materials advertised. Please check the title of the book to determine if it should include any access cards, study guides, lab manuals, CDs, etc.

The Used, Rental and eBook copies of this book are not guaranteed to include any supplemental materials. Typically, only the book itself is included. This is true even if the title states it includes any access cards, study guides, lab manuals, CDs, etc.