一起500kV刀闸误动事故的隐性原因分析

Hidden Cause Analysis of a Case of 500kV Isolating Switch Maloperation

介绍了某500 kV变电站的一起由于刀闸误动导致500 kV线路发生单相接地跳闸的事故,分析了刀闸误动的各种原因,通过Matlab软件对刀闸合闸接触器和控制电缆对地电容构成的RLC二阶暂态回路进行仿真分析,结合仿真结果和现场试验,最终把事故原因锁定在刀闸接触器参数不合格导致合闸接触器动作电压满足条件,并针对刀闸控制回路存在的缺陷提出了改进方案。

Introduction was made to a case of500kV line single-phase grounding tripping accident caused by the isolating switch maloperation in certain500kV transformer substation.This paper analyzed various kinds of causes leading to the isolating switch maloperation,and carried out simulation and analysis to the RLC second order transient state circuit composed of the isolating switch closing contactor and the controlling cable ground capacitance by the software Matlab.The simulation result and field tests show that accident cause is that the isolating switch contactor parameter disqualification brings about the satisfying isolating switch contactor operation voltage conditions.This paper raised the improved scheme for the defects existing in the isolating switch control circuit.