一起220kV变电站直流系统接地故障查找及分析

叙述了一起220kV变电站直流系统复杂接地故障的查找过程。借助便携式直流接地探测器，经过认真细致的检查，分别找出了2499断路器汇控柜连接电缆的电缆芯对地绝缘不良、2493断路器汇控柜中继电器线圈因跨段接线造成直流一直流串电以及主变压嚣的Ⅰ段和Ⅱ段重动电源正极串电的故障，井予以解决。最后进行了理论分析，并对该站现有直流系统存在的问题提出了解决方法。

Detection and analyses of a DC system grounding fault in a 220 kV substation

In this paper, the detection of a complex DC system grounding fault in a 220 kV substation is described. With the aid of the portable DC grounding detector and upon careful investigation, it was found that there existed the faults of poor ground insulation of connecting cable core in the control cubicle of Circuit Breaker 2499, mixed connection of relay windings in the control cubicle of Circuit Breaker 2493, and mixed connection between the repeating power sources of two DC circuits of a main transformer. Corresponding measures were taken and the faults eliminated. Solutions to the problems of the existing DC system in the substation are also offered based on theoretical analysis .