一起干式变压器跳闸事故原因分析

Accident Analysis of a Dry Transformer Tripping

电力变压器的短路在电网运行中是无法绝对避免同时又是危害较大的变压器故障,短路试验作为标准GB/T1094.5中规定的一项特殊试验,是考核电力变压器耐受外部引起短路的热稳定和动稳定效应的主要手段。该文基于一起干式变压器跳闸事故,从分析短路试验原理入手,通过对短路试验系统各设备的电气性能、监测数据、实物拆解三方面分别排查,并通过数据仿真定性分析,发现变压器高压绕组连杆制造工艺不良造成的绝缘击穿和维护保养不及时导致的灰尘异物进入箱体是引起干式变压器跳闸的原因。

The short-circuit of power transformer is one of the serious transformer faults in the operation of power grid,which will not only be seldom avoided but be harmful to the operation of power grid as well.As a special test specified in standard GB/T1094.5,the short circuit test is the main means to check the thermal stability and dynamic stability effect of power transformer.This paper,based on a dry-type transformer tripping accident,firstly analyzes the principle of short circuit test,and then investigates the electrical performance,the monitor data and the physical disassembling of the equipment in the short circuit test system.Meanwhile,by qualitative analysis of data simulation,this paper draws the conclusion that the reason for dry-type transformer tripping is the insulation breakdown caused by poor manufacturing technology of high-voltage winding connecting rod of transformer and the dust as well as foreign matter entering the box caused by the improper maintenance.