一起主变压器差动保护误动事件分析

Analysis on Differential Protection Misoperation Accident of Main Transformer

某220 kV变电站主变压器差动保护在相邻变电站220 kV出线发生瞬时单相接地故障时动作跳闸,切除变压器。经过现场设备排查及对各相关微机保护装置的录波、采样文件进行对比和分析,认定为一起主变压器差动保护误动事故。介绍了事故发生的过程及系统的运行方式,分析了事故的根本原因,提出了事先通过检查发现潜在缺陷的方法。

The differential protection of the main transformer in 220 kV substation trips and disables the transformer when the instantaneous single-phase ground fault occurs in 220 kV outlet in adjacent substation.After the scene investigation and the wave recording of relevant microcomputer protection devices,sampling file comparison and analysis are performed.It is identified as the main transformer differential protection misoperation accident.This paper introduces the accident process and the operation mode of the system,analyses the reason,and proposes the method of identifying potential defects through examination in advance.