With emphasis on power system protection from the network
operator perspective, this classic textbook explains the
fundamentals of relaying and power system phenomena including
stability, protection and reliability. The fourth edition brings
coverage up-to-date with important advancements in protective
relaying due to significant changes in the conventional electric
power system that will integrate renewable forms of energy and, in
some countries, adoption of the Smart Grid initiative.

New features of the Fourth Edition include:

* an entirely new chapter on protection considerations for
renewable energy sources, looking at grid interconnection
techniques, codes, protection considerations and
practices.

* new concepts in power system protection such as Wide Area
Measurement Systems (WAMS) and system integrity protection (SIPS)
-how to use WAMS for protection, and SIPS and control with
WAMS.

* phasor measurement units (PMU), transmission line current
differential, high voltage dead tank circuit breakers, and relays
for multi-terminal lines.

* revisions to the Bus Protection Guide IEEE C37.234 (2009) and
to the sections on additional protective requirements and
restoration.

Used by universities and industry courses throughout the world,
Power System Relaying is an essential text for graduate
students in electric power engineering and a reference for
practising relay and protection engineers who want to be kept up to
date with the latest advances in the industry.

Stanley H. Horowitz, Retired Consulting Engineer, American Electric Power, BSEE City College of New York.
Mr Horowitz worked at American Electric Power Service Corp. from 1950 to 1989, serving as head of the System Protection Section and assistant head of the Electrical Engineering Division and Consulting Electrical Engineer.?He was a lecturer at Columbia University Graduate School and a guest lecturer at the Universities of Wisconsin, Marquette, Auburn, Virginia Polytechnic Institute, Rensselaer Polytechnic Institute, Massachusetts Institute of Technology, Lund University and Grenoble University. He is a Life Fellow of the IEEE and served as chairman of the IEEE/PES Power System Relaying Committee from 1975-1978. In 1995 he was elected to the National Academy of Engineering and in 2008 was awarded the PES Life Achievement Award. Mr Horowitz was chairman of Study Committee 34-Protection and Control of the International Conference on Large High Voltage Electric Systems (CIGRE) from 1980-1986. In 1997 he was awarded the CIGRE Attwood Associates Award. He has co-authored a textbook and authored over 24 technical papers; he was also editor-in-chief of the IEEE Power Engineering Society magazine "Computer Applications in Power" until 2002.

Arun G. Phadke, Retired Research University Distinguished Professor, Virginia Technical University, Life Fellow-IEEE, member National Academy of Engineering

With emphasis on power system protection from the network operator perspective, this classic textbook explains the fundamentals of relaying and power system phenomena including stability, protection, and reliability. The fourth edition brings coverage up to date with important advancements in protective relaying due to significant changes in the conventional electric power system that will integrate renewable forms of energy and, in some countries, adoption of the Smart Grid initiative.

New features of the fourth edition include:

• an entirely new chapter on protection considerations for renewable energy sources, looking at grid interconnection techniques, codes, protection considerations, and practices
• new concepts in power system protection, such as Wide Area Measurement Systems (WAMS) and system integrity protection schemes (SIPS)how to use WAMS for protection, and SIPS and control with WAMS
• phasor measurement units (PMUs), transmission line current differential, high-voltage dead-tank circuit breakers, and relays for multiterminal lines
• revisions to the Bus Protection Guide IEEE C37.234 (2009) and to the sections on additional protective requirements and restoration.

Used by universities and industry courses throughout the world, Power System Relaying is an essential text for graduate students in electric power engineering and a reference for practising relay and protection engineers who want to be kept up to date with the latest advances in the industry.

Preface to the Fourth Edition xi

Preface to the Third Edition xii

Preface to the Second Edition xiii

Preface to the First Edition xiv

1 Introduction to Protective Relaying 1

1.1 What is Relaying? 1

1.2 Power System Structural Considerations 2

1.3 Power System Bus Configurations 4

1.4 The Nature of Relaying 8

1.5 Elements of a Protection System 14

1.6 International Practices 18

1.7 Summary 19

Problems 19

References 23

2 Relay Operating Principles 25

2.1 Introduction 25

2.2 Detection of Faults 26

2.3 Relay Designs 30

2.4 Electromechanical Relays 31

2.5 Solid-State Relays 40

2.6 Computer Relays 44

2.7 Other Relay Design Considerations 45

2.8 Control Circuits: A Beginning 48

2.9 Summary 49

Problems 49

References 51

3 Current and Voltage Transformers 53

3.1 Introduction 53

3.2 Steady-State Performance of Current Transformers 54

3.3 Transient Performance of Current Transformers 61

3.4 Special Connections of Current Transformers 64

3.5 Linear Couplers and Electronic Current Transformers 67

3.6 Voltage Transformers 68

3.7 Coupling Capacitor Voltage Transformers 69

3.8 Transient Performance of CCVTs 72

3.9 Electronic Voltage Transformers 75

3.10 Summary 76

Problems 76

References 78

4 Nonpilot Overcurrent Protection of Transmission Lines 79

4.1 Introduction 79

4.2 Fuses, Sectionalizers, and Reclosers 81

4.3 Inverse, Time-Delay Overcurrent Relays 84

4.4 Instantaneous Overcurrent Relays 94

4.5 Directional Overcurrent Relays 96

4.6 Polarizing 98

4.7 Summary 102

Problems 102

References 105

5 Nonpilot Distance Protection of Transmission Lines 107

5.1 Introduction 107

5.2 Stepped Distance Protection 107

5.3 R-X Diagram 110

5.4 Three-Phase Distance Relays 114

5.5 Distance Relay Types 123

5.6 Relay Operation with Zero Voltage 124

5.7 Polyphase Relays 125

5.8 Relays for Multiterminal Lines 126

5.9 Protection of Parallel Lines 129

5.10 Effect of Transmission Line Compensation Devices 132

5.11 Loadability of Relays 134

5.12 Summary 136

Problems 136

References 138

6 Pilot Protection of Transmission Lines 139

6.1 Introduction 139

6.2 Communication Channels 140

6.3 Tripping Versus Blocking 144

6.4 Directional Comparison Blocking 145

6.5 Directional Comparison Unblocking 149

6.6 Underreaching Transfer Trip 150

6.7 Permissive Overreaching Transfer Trip 153

6.8 Permissive Underreaching Transfer Trip 154

6.9 Phase Comparison Relaying 155

6.10 Current Differential 158

6.11 Pilot Wire Relaying 159

6.12 Multiterminal Lines 160

6.13 The Smart Grid 163

6.14 Summary 163

Problems 164

References 165

7 Rotating Machinery Protection 167

7.1 Introduction 167

7.2 Stator Faults 168

7.3 Rotor Faults 183

7.4 Unba…