Fault Location and Service Restoration for Electrical Distribution Systems

Jian Liu, Professor, Xian University of Technology, China and Chief Engineer at Shaanxi Electric Power Research Institute, ChinaProfessor Liu received his Ph.D. in Electrical Engineering from Xi'an University of Technology, Xi'an, China. After graduation, he worked as an engineer at the Northwest Electric Power Corporation, as senior engineer at the Shaanxi Electric Power Corporation and Chief Engineer at the Shaanxi Electric Power Research Institute, respectively. Professor Liu started his research on distribution system and its automation in 1995. He established China's first urban Distribution Automation System (DAS) in Yinchuan Province. He published the paper 'The uniformed matrix algorithm of fault location for distribution systems' which was the country's first paper on fault location for distribution systems. He has published over 100 papers on modelling, analysis, planning, fault location, service restoration, network reconfiguration, feeder automation and self-healing for distribution systems. As the head of the DAS Testing Group of the State Grid Corporation of China, Prof. Liu established the DAS testing laboratory and has developed sets of simulation and testing equipment, and he has led and or supervised the testing work of over 80 DAS projects in China. He supervises all of the DAS standards of State Grid Corporation. Due to his contributions to electric power engineering, Prof. Liu has been awarded the national and provincial level of science and technology prizes on twelve occasions. He is a Senior Member of IEEE.Prof. Xinzhou Dong, Department of Electrical Engineering, Tsinghua University, China; CIEEE Fellow.Prof. Xingying Chen, Hohai University, China.Prof. Xiangqian Tong, Xi'an University of Technology, China.Mr. Xiaoqing Zhang, Senior Engineer, Shaanxi Electric Power Research Institute, China.Dr. Shming Xu, Senior Engineer, Shaanxi Electric Power Research Institute, China.

• About the Authors ixPreface xi1 Progresses and Prospects for Fault Processing in Distribution Grids 1Liu Jian1.1 Introduction 11.2 Progresses in Local Intelligence-Based Fault Processing 31.3 Progresses in Distributed Intelligence-Based Fault Processing 31.4 Progresses in Centralized Intelligence-Based Fault Processing 41.4.1 Fault Location 51.4.2 Fault Isolation and Service Restoration 51.5 Progresses in Single]Phase Grounding Fault Processing 61.6 Prospects 72 Fault Processing Based on Local Intelligence 9Tong Xiangqian and Liu Jian2.1 Introduction 92.2 Fault Processing Based on Local Intelligence for Distribution Networks 102.2.1 Auto-Reclosure Control 102.2.2 Automatic Backup Switching Control of the Reserve Source 112.2.3 Voltage Protection 132.2.4 Three-Section Over-Current Protection 142.2.5 Coordination between Current Protection Relaying and Auto-Reclosure 222.2.6 Directional Over-Current Protection 232.2.7 Longitudinal Current Differential Protection 252.2.8 The Second Harmonic Braking Criterion in Current Protection 282.3 Fault Protection of the Active Distribution Network 322.3.1 The Influence of Distributed Generation on Current Protection and the Adaptive Improvement of Protection 322.3.2 Influence of Distributed Generation on Auto]Reclosure and its Adaptive Improvements 382.3.3 Longitudinal Current Differential Protection of DG Connected Distribution Networks 402.4 Coordination of Multistage Protection in the Distribution Network 412.4.1 Time Difference Based Coordination of Multistage Protection in the Distribution Network 422.4.2 The Coordination of Multistage Protection Based on Three]Section Over]Current Protection in the Distribution Network 502.4.3 Coordination Modes and Setting Methods of Multistage Protection of Distribution Networks 582.4.4 Example Analysis 682.5 Summary 713 Fault Processing Based on Distributed Intelligence 73Liu Jian, Xu Shiming and Chen Xingying3.1 Introduction 733.2 FA based on Recloser and Voltage-Delay Type Sectionalizers 743.3 Reclosing with the Fast Over-Current Protection Mode 783.3.1 Basic Principle 783.3.2 Improvements 803.4 Fast Healing Approach based on Neighbor Communication 823.4.1 Basic Principle 823.4.2 Improvements 853.5 Conclusion and Summary 884 Fault Processing Based on Centralized Intelligence 89Liu Jian and Chen Xingying4.1 Introduction 894.2 Simplified Modeling of Distribution Grids 924.2.1 Distribution Network Structure 924.2.2 Simplified Load Flow Analysis 984.3 Interphase Short Circuit Fault Location 1034.3.1 Fault Location with Sufficient Information 1034.3.2 Fault Location with Insufficient Information 1114.3.3 Fault Location for Distribution Grids with DGs 1174.4 Fault Isolation and Service Restoration 1324.4.1 Fault Isolation 1334.4.2 Service Restoration 1354.4.3 Modeled Service Restoration 1524.4.4 Coordination of the Four Types of Service Restoration 1594.5 Conclusion and Summary 1615 Single Phase to Ground Fault Processing 163Dong Xinzhou and Shi Shenxing5.1 Types of Ground Fault and Protection Strategy 1645.1.1 The Neutral Grounding Mode and Ground Fault Types 1645.1.2 The Protection Strategies for Different Types of Ground Faults 1675.2 Detection of High Resistance Ground Faults in Low Resistance Grounded Systems 1685.2.1 High Resistance Ground Faults 1685.2.2 Zero Sequence Inverse-Time Overcurrent Protection 1695.2.3 Grounded Protection based on the Amplitude and Phase of the Third Harmonic Current 1705.3 Grounding Protection in the System with Neutral Isolated 1745.3.1 Characteristics of Single-Phase-to-Ground Faults in Systems with Neutral Isolated 1745.3.2 Single-Phase-to-Ground Protection in Grids with Neutral Isolated 1795.4 Grounding Protection in the System with Neutral Grounded Through an Arc Suppression Coil 1805.4.1 Characteristics of Single-Phase-to-Ground Faults in Systems with Neutral Grounded through an Arc Suppression Coil 1815.4.2 Single-Phase-to-Ground Protection in Systems with Neutral Grounded through an Arc Suppression Coil 1855.5 Single-Phase-to-Ground Fault Feeder Selection Technology in a Power Distribution System with Neutral Non-Effectively Grounded 1865.5.1 Comparison of Magnitude and Phase based Single-Phase-to-Ground Fault Feeder Selection Methods 1875.5.2 Characteristics of Single-Phase-to-Ground Fault Generated Current Traveling Waves 1875.5.3 Current Traveling Wave-based Fault Feeder Selection Method 1945.6 Prevention of and Protection from Single]Phase]to]Ground Faults in Power Distribution Systems with Neutral Non-Effectively Grounded 1955.6.1 Basic Principle of Single-Phase-to-Ground Fault Prevention 1955.6.2 Single-Phase-to-Ground Fault Prevention Technology 1965.7 Single-Phase-to-Ground Fault Location in Systems with Neutral Non]Effectively Grounded 1985.7.1 Single-Phase-to-Ground Fault Generated Initial Traveling Waves 1985.7.2 Single-Phase-to-Ground Fault Location Method based on Propagation Speed of Traveling Waves 2025.8 Conclusion and Summary 2036 Practical Aspects of Fault Processing 204Liu Jian and Zhang Xiaoqing6.1 Introduction 2046.2 Coordination of Fault Processing Approaches 2056.2.1 Fault Processing Performance of Various Methodologies 2056.3 Planning of Terminal Units 2146.3.1 Elements Affecting the Reliability of Service 2146.3.2 Cost-Benefit Analysis of Action Node Planning 2156.3.3 Planning the Amount of Terminal Units to Meet the Requirement of Service Reliability 2176.4 Verification of the Property of Fault Processing 2266.4.1 Master Injection Testing Methodology and the Testing Tool 2276.4.2 Secondary Synchronous Injection Testing Methodology and Testing Facilities 2316.4.3 Master and Secondary Synchronous Injection Testing Methodology 2326.4.4 Direct Short-Circuit Test 2346.4.5 Comparison of the Four Testing Methodologies 2356.5 Conclusion and Summary 235References 238Index 242