一起高阻接地故障引起的500kV线路保护动作行为分析

With high resistance grounding fault caused by 500kV line protection action analysis

线路发生高阻接地故障,不仅会降低电网供电的可靠性,还会严重影响电网的安全稳定运行,造成重大损失。线路发生高阻接地时,由于过渡电阻很大,故障电流水平通常低于金属性短路故障电流水平,引起的故障电流突变量很小,甚至为零,接地相电压降幅很小、三相线电压依然保持对称,使得高阻接地的判别难度增加;本文通过对一起500kV线路单相经高阻接地故障时不同保护原理装置的动作过程进行分析,为线路新建及改造的保护装置选型提供参考。

High resistance grounding fault line,will not only reduce the reliability of power supply,but also seriously affect the safe and stable operation ofpower grid,causing major losses.High resistance grounding lines,due to the transition resistance,fault current levels are usually lower than metallic short circuit fault current,fault current variation caused by the very small,or even zero,the grounding phase voltage drop is very small,the three-phase line voltage remains symmetric,the high resistance grounding d iscriminationdifficulty increases;this paper the ground fault with high resistance of differentprotection principle of device operation process analysis of 500kV circuit single-phase,provides the reference for the device selection,construction and retrofit of line protection.