灵活接地配电网单相接地故障全过程特征分析  

Analysis of the Entire Process Characteristics of Single Phase-toground Faults in Flexible Grounded Distribution Networks

作　　者：廖德辉 金鑫[2] 田君杨 李海勇 蒋连钿 LIAO Dehui;JIN Xin;TIAN Junyang;LI Haiyong;JIANG Liandian(Guangxi Power Grid Power Dispatching Control Center,Nanning 530023,China;College of New Energy,China University of Petroleum,Qingdao 266580,China)

机构地区：[1]广西电网电力调度控制中心,广西南宁530023 [2]中国石油大学(华东)新能源学院,山东青岛266580

出　　处：《智慧电力》2024年第5期90-97,共8页Smart Power

基　　金：国家自然科学基金资助项目(52077221);南方电网公司科技项目(046000KK52220008)。

摘　　要：为进一步明确灵活接地方式下的单相接地故障特征,给新型接地保护原理的研究提供理论依据,通过建立涵盖灵活接地配电网接地故障全过程的等值电路,分析系统内各检测点处典型故障电气量的幅值、相位特征及其在不同阶段内的变化规律。相比于中性点接地电阻投入之前,在不同故障情况下,故障点电流始终增大,系统零序电压及健全线路零序电流始终减小,而故障线路零序电流随故障点接地电阻的增大而先增大后减小。这与灵活接地方式推行的初衷并不完全相符,解释了目前现场常用的传统小电阻零序过电流保护效果不如理想预期的原因。数字仿真与现场人工试验均验证了本文所得结论的正确性。To further clarify the characteristics of single phase-to-ground faults under flexible grounding methods and provide theoretical basis for the research of new grounding protection principles,an equivalent circuit covering the entire process of ground faults in flexible grounded distribution network is established.The amplitude and phase characteristics of typical fault electrical quantities at various detection points,variation patterns in different stages are analyzed.Compared with situation before the neutral point grounding resistance is applied,under different fault conditions,the current fault point always increases,and the system zero sequence voltage and zero sequence current of healthy lines always decrease.However,the zero sequence current of fault line increases firstly and then decreases with the increasing of the fault point grounding resistance.This is not entirely consistent with the original intention of implementing flexible grounding methods,which explains the reason why the traditional small-resistance zero-sequence overcurrent protection commonly used in the field is not as effective as expected.Both digital simulation and on-site manual experiments have verified the correctness of the conclusions drawn in this paper.

关 键 词：灵活接地系统 接地保护 故障阶段 故障特征 

分 类 号：TM771[电气工程—电力系统及自动化]