中性点不接地系统并联线路异名相两点接地故障分析  

Analysis on Two⁃Point Grounding Faults of Synonymous Phase for Parallel Line of Isolated Neutral System

作　　者：刘炬 徐达 廖玄[1] 熊进 刘飞 刘闯 LIU Ju;XU Da;LIAO Xuan;XIONG Jin;LIU Fei;LIU Chuang(SGCC Jingmen Power Supply Company,Jingmen 448000,China;China University of Geosciences,Wuhan 430074,China)

机构地区：[1]湖北省电力有限公司荆门供电公司,湖北荆门448000 [2]中国地质大学,武汉430074

出　　处：《内蒙古电力技术》2022年第3期38-45,共8页Inner Mongolia Electric Power

基　　金：中国博士后基金面上资助项目“风-光-地热园区综合能源系统的多能互补建模与协同优化”(2021M692992)。

摘　　要：并联线路异名相两点接地是中性点不接地系统中威胁配电网安全稳定运行的主要原因,其故障发展机理和特征规律对电力系统事故分析及事故防范具有重要意义。针对中性点不接地系统并联线路异名相两点接地故障,基于对称分量法建立系统故障模型,并通过系统等值电路对故障电气量进行理论分析。结合某110 kV变电站内由单点接地发展为并联线路异名相多点接地的故障实例,分析继电保护装置故障录波图特征规律及继电保护装置的动作行为,辨识出故障发生前后电气量的变化特征,接地两相线路故障电流及零序电流均大小相等、方向相反。并通过MATLAB/Simulink仿真平台搭建仿真模型对故障特征进行了验证。The two⁃point grounding faults of synonymous phase for parallel line is the main reason that threatening the safe and stable operation of power grid in the isolated neutral system.The fault development mechanism and characteristic law is of great significance to power system fault analysis and prevention.Aiming at the two⁃point grounding faults of heterogeneous phase for parallel line in isolated neutral system,the fault model is established based on symmetrical component method,and the characteristic law of the fault is analyzed theoretically through the system equivalent circuit.Combined with a fault example in a 110 kV substation that developed from single⁃point grounding to multi⁃point grounding of heterogeneous phase for parallel line,the characteristic law of fault oscillogram and the action behavior of relay protection device are analyzed.The variation characteristics of electrical quantity before and after the fault are identified.The result shows that the fault current and zero⁃sequence current of the grounded two⁃phase line are equal in magnitude and opposite in direction.The fault characteristics are verified by building a simulation model through the MATLAB/Simulink simulation platform.

关 键 词：中性点不接地系统 继电保护 两点接地故障 小电流接地 金属性接地 配电网 

分 类 号：TM77[电气工程—电力系统及自动化]