220kV变压器低压侧异相两点接地分析

220 kV变压器低压侧异相两点同时接地事故较为少见,而不同接地点中一点在变压器差动保护范围外、一点在差动保护范围内并引起变压器差动保护动作跳闸的事例更为少见也更加容易造成误判。对220kV电网中的一起典型事故做了详细分析,借助故障数据描述了事故时的故障现象,指出了对于此类故障的分析思路,对变压器低压侧复杂事故的分析和判断具有指导意义和参考价值。

Analysis of double-phases earth fault in the low-side of a 220 kV-transformer

Double-phases earth fault in the low-side 35 kV busbar of a 220 kV-transformer is not very often,and among the faults which one earthing contact located inside the transformer differential protection area and the another one outside of the area is even more seldom.With the demonstration of some real-time fault data,this paper presents a detailed analysis of a typical power outage caused by that kind of earth fault and describes the whole process of the trouble.A way to analyze other similar power transformer faults is proposed.It has a reference value to deal with power grid failures.