一起接地变保护动作跳闸原因的分析

由于接地变中性点避雷器击穿,使10kV系统由中性点经消弧线圈接地系统变为中性点经小电阻接地系统。当10kV系统发生B相接地故障时,虽然故障点不在接地变,但接地变A、C相电流互感器测得很大的电流,超过过流I段定值,使接地变跳开。本文对保护动作的原因及故障点进行了分析,并提出了相关的解决对策。

Analysis on a Relay Action of Earthed Transformer

For the breakthrough of the neutral arrester of the earthed transformer, the 10kV system becomes from the arc suppression coil neutral grounding system to the low resistance neutral grounding system. While the B phase of the 10kV system is under the earth fault, although the fault point is not on the earthed transformer, the testing current of the current transformer on A and C phase is much greater than the value of the section I, so the earthed transformer will action. This paper analysis the reasons of t...