一起线路故障引起主变差动保护误动的分析

Analysis of primary differential protection error caused by a line failure

本文介绍一起因110kV终端变电站35kV线路故障引起主变差动保护误动作的案例。通过对保护动作报文、事故录波、CT升流、伏安特性、绝缘检查等现场检查,确定主变中压侧B相电压互感器二次差动保护绕组发生故障,对主变差动保护情况进行分析,得出结论,即动作情况满足主变差动逻辑条件,并提出解决方案。

This paper introduces a case of main variable differential protection error due to the failure of the 350 kV substation at the 110 kV terminal, and passes on-site inspections such as protection action message, accident record wave, CT lift flow, voltammetry characteristics, and insulation inspection. The failure of the secondary differential protection winding of the B-phase voltage Transformer in the main variation is determined, and the main variation differential protection is analyzed. It is concluded that the action situation satisfies the main variation dynamic logic conditions, and the correct action is proposed.