Cover
Title Page
About the Authors
Preface
1 Progresses and Prospects for Fault Processing in Distribution Grids
1. 1.1 Introduction
2. 1.2 Progresses in Local Intelligence-Based Fault Processing
3. 1.3 Progresses in Distributed Intelligence-Based Fault Processing
4. 1.4 Progresses in Centralized Intelligence-Based Fault Processing
5. 1.5 Progresses in Single-Phase Grounding Fault Processing
6. 1.6 Prospects
2 Fault Processing Based on Local Intelligence
1. 2.1 Introduction
2. 2.2 Fault Processing Based on Local Intelligence for Distribution Networks
3. 2.3 Fault Protection of the Active Distribution Network
4. 2.4 Coordination of Multistage Protection in the Distribution Network
5. 2.5 Summary
3 Fault Processing Based on Distributed Intelligence
1. 3.1 Introduction
2. 3.2 FA based on Recloser and Voltage-Delay Type Sectionalizers
3. 3.3 Reclosing with the Fast Over-Current Protection Mode
4. 3.4 Fast Healing Approach based on Neighbor Communication
5. 3.5 Conclusion and Summary
4 Fault Processing Based on Centralized Intelligence
1. 4.1 Introduction
2. 4.2 Simplified Modeling of Distribution Grids
3. 4.3 Interphase Short Circuit Fault Location
4. 4.4 Fault Isolation and Service Restoration
5. 4.5 Conclusion and Summary
5 Single Phase to Ground Fault Processing
1. 5.1 Types of Ground Fault and Protection Strategy
2. 5.2 Detection of High Resistance Ground Faults in Low Resistance Grounded Systems
3. 5.3 Grounding Protection in the System with Neutral Isolated
4. 5.4 Grounding Protection in the System with Neutral Grounded Through an Arc Suppression Coil
5. 5.5 Single-Phase-to-Ground Fault Feeder Selection Technology in a Power Distribution System with Neutral Non-Effectively Grounded
6. 5.6 Prevention of and Protection from Single-Phase-to-Ground Faults in Power Distribution Systems with Neutral Non-Effectively Grounded
7. 5.7 Single-Phase-to-Ground Fault Location in Systems with Neutral Non-Effectively Grounded
8. 5.8 Conclusion and Summary
6 Practical Aspects of Fault Processing
1. 6.1 Introduction
2. 6.2 Coordination of Fault Processing Approaches
3. 6.3 Planning of Terminal Units
4. 6.4 Verification of the Property of Fault Processing
5. 6.5 Conclusion and Summary
References
Index
End User License Agreement

List of Tables

Chapter 02
1. Table 2.1 The ratio of the critical length to the whole length of the feeder (l_total = 10 km)
2. Table 2.2 The ratio of the critical length to the whole length of the feeder (l_total = 5 km)
3. Table 2.3 The ratio of the critical length to the whole length of the feeder (l_total = 2 km)
4. Table 2.4 Current settings of each protection on the trunk lines in situation 1
5. Table 2.5 Current settings of each protection on the trunk lines in situation 2
Chapter 04
1. Table 4.1 The relationship between the four types of node
2. Table 4.2 Load reach limitations to guarantee Criterion 4.1 effective for a radial feeder (km) (Inverter type DGs with γ = 25%)
3. Table 4.3 Load reach limitations to guarantee Criterion 4.1 effective for a radial feeder (km) (Inverter type DGs with γ = 50%)
4. Table 4.4 Load reach limitations to guarantee Criterion 4.1 effective for looped feeders (km) (Inverter type DGs with γ = 25%)
5. Table 4.5 Load reach limitations to guarantee Criterion 4.1 effective for looped feeders (km) (Inverter type DGs with γ = 50%)
6. Table 4.6 Capacity limitations of inverter-type DGs to guarantee Criterion 4.1 effective for cable feeders
7. Table 4.7 Capacity limitations of inverter-type DGs to guarantee Criterion 4.1 effective for overhead feeders
8. Table 4.8 Load reach limitations to guarantee Criterion 4.1 effective for a radial feeder (km) (Machine-type DGs with γ = 12.5%)
9. Table 4.9 Load reach limitations to guarantee Criterion 4.1 effective for a radial feeder (km) (Machine-type DGs with γ = 25%)
10. Table 4.10 Load reach limitations to guarantee Criterion 4.1 effective for looped feeders (km) (Machine-type DGs with γ = 12.5%)
11. Table 4.11 Load reach limitations to guarantee Criterion 4.1 effective for looped feeders (km) (Machine-type DGs with γ = 25%)
12. Table 4.12 Capacity limitations of machine-type DGs to guarantee Criterion 4.1 effective for cable feeders
13. Table 4.13 Capacity limitations of inverter-type DGs to guarantee Criterion 4.1 effective for overhead feeders
14. Table 4.14 The outage losses of the action regions of the example shown in Figure 4.28
15. Table 4.15 The control steps for service restoration process of the example shown in Fig. 4.28
16. Table 4.16 The maximum utilization rates of a multi-sectioned and multi-linked grid
17. Table 4.17 The maximum utilization rate of M-supplying and one back-up grids
Chapter 05
1. Table 5.1 Typical values of high resistance fault currents in grounded systems
Chapter 06
1. Table 6.1 Comparisons of various fault processing approaches
2. Table 6.2 Fault ratios per kilometer of overhead lines and cables in China
3. Table 6.3 The averaged outage duration time of one fault in China
4. Table 6.4 The results of planning
5. Table 6.5 The comparison of the four testing methodologies
6. Table 6.6 The facilities required by the four testing methodologies

List of Illustrations

Chapter 02
1. Figure 2.1 The principle diagram of three-phase single-shot reclosing
2. Figure 2.2 The wiring of reserve-source (a) and APD configuration (b)
3. Figure 2.3 Tie switches with APD
4. Figure 2.4 The operation logic of three-section current protection
5. Figure 2.5 Instantaneous over-current protection of single-ended radial distribution network
6. Figure 2.6 Coordination of time delay instantaneous over-current protection with instantaneous over-current protection for next segment
7. Figure 2.7 The scalar principle of the time-delay setting of definite time over-current protection
8. Figure 2.8 The coordination of three section over-current protection for a multi-segmented feeder
9. Figure 2.9 Instant accelerated protection trip
10. Figure 2.10 Delayed auto-reclosing protection trip
11. Figure 2.11 Directional over-current protection
12. Figure 2.12 The necessity of directional element
13. Figure 2.13 The schematic diagram for longitudinal current differential protection
14. Figure 2.14 The characteristic of differential current protection with ratio restraint
15. Figure 2.15 The braking area based on the amplitude ratio and the phase difference
16. Figure 2.16 DG connected to the distribution bus
17. Figure 2.17 DG located in the middle of a feeder
18. Figure 2.18 DG located in the end of feeder
19. Figure 2.19 Influence of distributed generation on auto-reclosing and its improvement measure
20. Figure 2.20 Configuration of longitudinal current differential protection in distribution grids with DG
21. Figure 2.21 The range possessing the multistage differential protection coordination conditions
22. Figure 2.22 The upstream shift of a critical length point in the non-maximum mode operation of the system
23. Figure 2.23 Fan-like power range of the feeder
24. Figure 2.24 Schematic of configurable n-stage protection
25. Figure 2.25 Critical surface of four-stage protection coordination under the traditional setting method
26. Figure 2.26 Critical surface of four-stage protection coordination under the improved coordination method
27. Figure 2.27 First example of multistage protection configuration in a “hand-in-hand” ring network
28. Figure 2.28 Second example of multistage protection configuration in a “hand-in-hand” ring network
29. Figure 2.29 Typical coordination modes of multistage protection in distribution network
30. Figure 2.30 A 10 kV distribution network of a village
Chapter 03
1. Figure 3.1 Composition of the voltage time type sectionalizer
2. Figure 3.2 The fault processing of a radial grid
3. Figure 3.3 The fault processing of an open-loop hand-in-hand grid
4. Figure 3.4 The temporary fault processing for reclosing with fast over-current protection mode
5. Figure 3.5 The permanent fault processing for reclosing with fast over-current protection mode
6. Figure 3.6 The permanent fault processing for the improved reclosing with fast over-current protection mode
7. Figure 3.7 A typical open-loop distribution network
8. Figure 3.8 A typical close-loop distribution network
9. Figure 3.9 Two cascade power distribution switching stations
10. Figure 3.10 Fault processing in case of some of the fault information lost
11. Figure 3.11 Permanent fault processing in case of a circuit breaker failed to operate
Chapter 04
1. Figure 4.1 A DAS and its information interchanging with the corresponding systems
2. Figure 4.2 An example to illustrate the four types of nodes
3. Figure 4.3 The action regions of the example in Fig. 4.2
4. Figure 4.4 The monitoring regions of the example in Fig. 4.2
5. Figure 4.5 Dividing connected systems
6. Figure 4.6 The modeled groups of a two-sectioned and two-linked grid
7. Figure 4.7 The modeled groups of a three supplying and one back-up grid
8. Figure 4.8 An example of node and region hierarchies
9. Figure 4.9 The loads flowing through the nodes of the example in Fig. 4.2
10. Figure 4.10 The loads distributed from the regions obtained by executing node-to-region load transform
11. Figure 4.11 The obtained loads through the nodes in a candidate configuration by executing region-to-node load transform
12. Figure 4.12 An example of fault location for single source open-loop distribution grids
13. Figure 4.13 An example of fault location for multi-main-source close-loop distribution grids
14. Figure 4.14 Some typical cases of two phase short circuit to ground fault
15. Figure 4.15 Examples to illustrate the separability of multiple single region fault location
16. Figure 4.16 Examples to illustrate the separability of multiple multi-region faults location
17. Figure 4.17 Examples to illustrate fault location with insufficient information
18. Figure 4.18 An example of looped feeder pair with DGs
19. Figure 4.19 An example of fault location based on coordinating the reclosing procedure and cutting out the DGs
20. Figure 4.20 An example of fault location based on over-heat region searching approach
21. Figure 4.21 The whole program of fault isolation
22. Figure 4.22 Examples of fault isolation for the distribution grid in Fig. 4.2
23. Figure 4.23 A general process of optimal real-time service restoration scheme searching
24. Figure 4.24 An example of real-time service restoration
25. Figure 4.25 Initial positions of virtual open action nodes (VOAN)
26. Figure 4.26 Candidate solutions in Tabu searching for the example shown in Fig. 4.25
27. Figure 4.27 An example of service restoration with minimum load shedding
28. Figure 4.28 A distribution grid as an example of service restoration to avoid large area breakdown
29. Figure 4.29 An example of correction control in a service restoration process
30. Figure 4.30 Typical two-sectioned and two-linked grids
31. Figure 4.31 Typical three-sectioned and three-linked grids
32. Figure 4.32 The modeled service restoration scheme of a three-sectioned and three-linked grid
33. Figure 4.33 Typical multi-supplying and one back-up grids
34. Figure 4.34 Without the idle feeder, the grid is not a two-supplying and one back-up grid
35. Figure 4.35 The modeled service restoration scheme of three-supplying and one back-up grid
36. Figure 4.36 The modeled service restoration scheme of a 4 × 6 connection grid
37. Figure 4.37 Coordination of the four types of service restoration
Chapter 05
1. Figure 5.1 Classification of neutral grounding mode
2. Figure 5.2 Neutral directly grounded
3. Figure 5.3 Neutral grounded through low-resistance
4. Figure 5.4 Non-grounded system
5. Figure 5.5 Arc suppression coil grounded system
6. Figure 5.6 Current-time characteristic curve of high inverse-time current relay
7. Figure 5.7 Waveform of high resistance fault current and (a) third harmonic current; (b) ratio of third harmonic current in the fault current
8. Figure 5.8 Voltage, current, and current decomposition waveforms
9. Figure 5.9 The phase relations between fault point and relay location
10. Figure 5.10 Phase shift analysis of fundamental voltage and third harmonic current
11. Figure 5.11 The schematic of simple network
12. Figure 5.12 Vectors when phase A is grounded
13. Figure 5.13 Capacitance current distribution diagram in three-phase system when single phase is grounded
14. Figure 5.14 Zero sequence circuit (corresponding Fig. 5.13) and vectors
15. Figure 5.15 Construction diagram of zero sequence current direction protection
16. Figure 5.16 Current distribution when a single-phase-to-ground fault occurs in the grid with neutral grounded through arc suppression coil: (a) three-phase system, (b) zero sequence equivalent circuit
17. Figure 5.17 Transient current distribution under single-phase-to-ground fault
18. Figure 5.18 Transient single-phase-to-ground fault current waveform
19. Figure 5.19 Equivalent circuit to analyze the transient process
20. Figure 5.20 Post-fault power system and its decomposition. (a) Post-fault power system; (b) equivalent circuit of post-fault power system; (c) normal-operating network; and (d) fault superimposed network
21. Figure 5.21 Single line equivalent circuit with distributed parameters and propagation of fault generated traveling waves
22. Figure 5.22 Power distribution system with one bus and N feeders
23. Figure 5.23 Reflection and refraction of incident traveling waves at the bus
24. Figure 5.24 Module traveling waves equivalent circuit
25. Figure 5.25 Flow chart of single-phase-to-ground fault prevention
26. Figure 5.26 Boundary conditions of single-phase-to-ground fault
27. Figure 5.27 Basic principle of single-phase-to-ground fault location based on propagation speed of traveling waves
Chapter 06
1. Figure 6.1 Six steps of the fault processing procedure
2. Figure 6.2 An example of coordination of DAS and relay protection for fault processing
3. Figure 6.3 Examples to explain the amount of FTUs for cable feeders
4. Figure 6.4 The master injection testing methodology
5. Figure 6.5 Structure of the master injection testing tool
6. Figure 6.6 Flowchart of fault simulation
7. Figure 6.7 Schematic diagram of secondary synchronous injection test method
8. Figure 6.8 The master and secondary synchronous injection testing methodology to avoid service interruption during the test
9. Figure 6.9 The master and secondary synchronous injection testing method to reduce the numbers of workers and facilities
10. Figure 6.10 A direct short-circuit test system

Pages

This edition first published 2016
© 2016 China Electric Power Press. All rights reserved.

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Library of Congress Cataloging-in-Publication Data

Names: Liu, Jian (Electrical engineer)
Title: Fault location and service restoration for electrical distribution systems / Jian Liu.
Description: Singapore : John Wiley & Sons, Inc., 2016. | Includes bibliographical references and index.
Identifiers: LCCN 2015047270 | ISBN 9781118950258 (cloth) | ISBN 9781118950272 (ePDF) | ISBN 9781118950265 (ePUB)
Subjects: LCSH: Electric power systems–Maintenance and repair. | Electric fault location. | Electric power distribution.
Classification: LCC TK7870.2 .L58 2016 | DDC 621.319/130288–dc23 LC record available at http://lccn.loc.gov/2015047270

About the Authors

Professor, Ph.D., Liu Jian (b. 1967) is the Chief Engineer at the Shaanxi Electric Power Research Institute. He is also a Senior Member of IEEE. He has published over 100 papers and nine books on theory, analysis, automation and planning for distribution systems, some of which are used as text books or reference books for university students. Professor Liu’s theory and algorithms have been applied in most of the DAS products and projects in China. As the head of the DAS Testing Group, Professor Liu is responsible for testing the fault processing performance of all the DAS built by the State Grid Corporation of China. He supervises all of the DAS standards of State Grid Corporation. Due to his excellent contribution in electric power engineering, Professor Liu has been awarded national and provincial levels of science and technology prizes 18 times.

Professor, Ph.D., Dong Xinzhou (b. 1963) is a Professor of Electrical Engineering at Tsinghua University. His research interests focus on relay protection for electric power transmission and distribution systems. He is one of the top scientists in traveling-wave based protection and its applications.

Professor, Ph.D., Chen Xinying (b. 1964) is a Professor of Electrical Engineering. She is also the Vice President of Hohai University. Her research interests focus on analysis and control of electric power distribution systems. She is one of the top scientists in self-healing control in China.

Professor Xu Shiming (b. 1967) is the Manager of the Distribution System Branch of the Nanri Electric Automation Corp. He has developed series automation products for electric power dispatching, substation automation, and distribution automation, which are widely used in China.

Professor Tong Xiangqian (b. 1961) is a Professor of Electrical Engineering at the Xi’an University of Technology. His research interests focus on analysis and automatic control of electric power distribution systems with Distributed Generations (DG).

Mr. Zhang Xiaoqing (b. 1970) is the Director of the Electric Power Research Center, Shaanxi Electric Power Research Institute. He is also a senior engineer and the assistant to Professor Liu.

Professor Shi Shenxing (b. 1975) is an Associate Professor of Electrical Engineering at Tsinghua University. He is assistant to Professor Dong.

Professor Liao Yingchen (b. 1978) is an Associate Professor of Electrical Engineering at Hohai University. She is assistant to Professor Chen.

Preface

This book is the English edition of Fault Location and Service Restoration for Electrical Distribution Systems published by the China Electric Power Press (Beijing, 2013), published in Chinese. It is revised and expanded and some of the contents of another book written by the authors, that is, Relay Protection and Fault Processing for Distribution Systems published by China Electric Power Press (Beijing, 2014), have been combined in this book, with particular emphasis on the contributions of the authors.

Fault location and service restoration for distribution systems is realized by Distribution Automation System (DAS). The authors are practitioners in China and they are experts in theory, technique, manufacturing, and engineering of DASs. Professors Liu and Zhang are from the research institute, one of the top teams on distribution automation technology and testing techniques. Professors Dong, Chen, and Tong are from universities that are famous for distribution system theory investigation. Professor Xu is from Nari Corp., which is the largest manufacturing enterprise of DASs in China. The contents of this book are the contributions of these authors.

After long-term engineering practice, the authors realized that the simpler the DAS, the more reliable it is. Thus, the authors proposed simple modeling, analysis, and optimization approaches for DASs, with which, not only is the problem of a lack of measuring data solved, but also the decision making time is reduced.

The authors also realized that the local intelligence based fault processing technologies are faster and more reliable; the distribution intelligence based fault processing technologies, such as coordination of reclosers and sectionalizers, are simple and cost effective; the centralized intelligence based DAS may locate the fault over a smaller area and restore the service in an optimized strategy, thus a complicated fault may be processed satisfactorily. Therefore, fault processing performance may be improved by coordination of the three types of fault processing technologies. The authors’ experiences are the main contents of this book, which have been applied in DAS projects in over 70 cities in China.

The contents of this book are organized into six chapters. In Chapter 1, the progresses in fault processing for distribution grids are overviewed and the prospects are given. In Chapters 2–4, the interphase short circuit fault processing technologies based on local, distributed, and centralized intelligence are described, respectively. In Chapter 5, the single phase to ground fault processing technologies for neutral non effective grounding distribution systems are described. In Chapter 6, some practical aspects of fault processing are discussed, such as coordination of various fault processing approaches, planning of terminal units in DAS, and the testing and verification of fault processing performance.

In this book, Professor Liu translated and re-organized the contents of Chapters 1, 4, and 6. Professor Dong and Dr. Shi translated the contents of Chapter 5. Professor Tong translated and re-organized the contents of Chapter 2. Professor Chen translated and re-organized the contents of Chapter 3. The other authors of the Chinese version of this book carefully checked the translated manuscript.

The authors wish to thank many good friends and colleagues, including especially Professor Shen Bingbing, Professor Zhao Jianghe, Professor Liu Dong, Professor Song Guobing, Mr. Chen Yikai, Mr. Zhao Shuren, Mr. Zhang Zhihua, and Mr. Liu Bin for their encouragement and willing support, without which this book would never have been completed.

Liu Jian
Professor, Ph.D.