Understanding Power Quality Problems: Voltage Sags and Interruptions

PREFACE xiii

FTP SITE INFORMATION xv

ACKNOWLEDGMENTS xvii

CHAPTER 1 Overview of Power Quality and Power Quality Standards 1

1.1 Interest in Power Quality 2

1.2 Power Quality, Voltage Quality 4

1.3 Overview of Power Quality Phenomena 6

1.4 Power Quality and EMC Standards 22

CHAPTER 2 Long Interruptions and Reliability Evaluation 35

2.1 Introduction 35

2.2 Observation of System Performance 37

2.3 Standards and Regulations 48

2.4 Overview of Reliability Evaluation 50

2.5 Basic Reliability Evaluation Techniques 62

2.6 Costs of Interruptions 101

2.7 Comparison of Observation and Reliability Evaluation 106

2.8 Example Calculations 107

CHAPTER 3 Short Interruptions 115

3.1 Introduction 115

3.2 Terminology 115

3.3 Origin of Short Interruptions 116

3.4 Monitoring of Short Interruptions 121

3.5 Influence on Equipment 125

3.6 Single-Phase Tripping 127

3.7 Stochastic Prediction of Short Interruptions 136

CHAPTER 4 Voltage Sags—Characterization 139

4.1 Introduction 139

4.2 Voltage Sag Magnitude 140

4.3 Voltage Sag Duration 168

4.4 Three-Phase Unbalance 174

4.5 Phase-Angle Jumps 198

4.6 Magnitude and Phase-Angle Jumps for Three-Phase Unbalanced Sags 206

4.7 Other Characteristics of Voltage Sags 231

4.8 Load Influence on Voltage Sags 238

4.9 Sags due to Starting of Induction Motors 248

CHAPTER 5 Voltage Sags—Equipment Behavior 253

5.1 Introduction 253

5.2 Computers and Consumer Electronics 256

5.3 Adjustable-Speed AC Drives 265

5.4 Adjustable-Speed DC Drives 300

5.5 Other Sensitive Load 318

CHAPTER 6 Voltage Sags—Stochastic Assessment 325

6.1 Compatibility between Equipment and Supply 325

6.2 Presentation of Results: Voltage Sag Coordination Chart 328

6.3 Power Quality Monitoring 342

6.4 The Method of Fault Positions 359

6.5 The Method of Critical Distances 373

CHAPTER 7 Mitigation of Interruptions and Voltage Sags 389

7.1 Overview of Mitigation Methods 389

7.2 Power System Design—Redundancy Through Switching 397

7.3 Power System Design—Redundancy through Parallel Operation 405

7.4 The System-Equipment Interface 419

CHAPTER 8 Summary and Conclusions 453

8.1 Power Quality 453

8.2 Standardization 455

8.3 Interruptions 456

8.4 Reliability 457

8.5 Characteristics of Voltage Sags 458

8.6 Equipment Behavior due to Voltage Sags 459

8.7 Stochastic Assessment of Voltage Sags 460

8.8 Mitigation Methods 462

8.9 Final Remarks 462

BIBLIOGRAPHY 465

APPENDIX A Overview of EMC Standards 477

APPENDIX B IEEE Standards on Power Quality 481

APPENDIX C Power Quality Definitions and Terminology 485

APPENDIX D List of Figures 507

APPENDIX E List of Tables 525

INDEX 529

ABOUT THE AUTHOR 543