高电压绝缘监视柜电压互感器烧损事故分析

举某矿井下10 kV线路单相接地事故的实例,从接地保护及开口三角形绕组的工作原理着手。分析了发生接地事故的原因以及查找接地事故的方法。正常情况下,开口三角形绕组零序电压为0 V;当系统单相接地,开口三角形绕组零序电压达到30 V整定值时,零序电压继电器动作,发出接地信号。开口三角形绕组的错误接线会导致开口三角形环流,造成电压互感器烧损。将两组开口三角形绕组独立运行便可避免该事故的发生。

Analysis of Damage Accident of Voltage Transformers in High Voltage Insulation Monitoring Cabinet

Takes one 10 kV underground coal mine single grounding accident as the example,the reasons that lead grounding accident happen are analyzed from grounding protection and open-delta winding zero-sequence voltage working principle.Under normal circumstance,the open-delta winding zero sequence voltage is zero.When the system single grounding happens,the open-delta winding zero sequence voltage achieves 30 V,the zero sequence voltage relay sends grounding signal.This damage accident of voltage transformers is on account of wiring error,which causes voltage transformer burn down.If two groups open-delta winding units operate separately,which can avoid accident happen.