一种典型10 kV电缆线路接地故障快速隔离动作分析

Analysis of fast isolation action of a typical 10 kV cable line grounding fault

针对一起变电站中性点接地方式改造过程中零序跳闸事件,提出10 kV电缆线路的典型拓扑结构。结合实际工作,阐述当前试点应用中的经消弧线圈并联小电阻接地方式,并给出零序保护定值推荐值。结合案例,全面分析接地变跳闸逻辑错误、电缆线路FA自愈失败等故障原因,并提出改进措施。

The typical topological structure of 10 kV cable line is summarized and proposed according to the zero sequence trip event during the transformation of neutral grounding mode of substation.Combined with the practical work,the parallel small resistance grounding mode with arc suppression coil in the current pilot application is introduced in detail,and the recommended value of zero sequence protection is given.Combined with the case,the fault treatment process is explained in depth,the fault causes such as ground change tripping logic error and FA self-healing failure of cable lines are comprehensively analyzed,and the improvement measures are proposed,which lays a practical foundation for the key work of rapid isolation of grounding fault of urban distribution network.