220kV变压器高压套管末屏故障原因分析与处理

Analysis on reasons of high voltage bushing end shield fault of 220kV transformer and treatment

某电厂1台220 kV变压器高压侧B相套管末屏存在严重放电痕迹,套管内绝缘油中检验出超标的乙炔,通过分析,判断故障原因为套管在线检测装置设计、安装存在缺陷,导致运行中末屏接地线断裂,末屏悬浮电位升高而放电。提出了一种现场不排油更换套管的方法,节约了大量的人力、物力,缩短了检修工期。

There were serious electric discharge vestiges existing in high voltage side phase B bushing end shield of the 220kV transformer in a power plant.The acetylene exceeding the standard was inspected out in the insulating oil in the bushing.Based on analysis,it was judged that the fault reason is the defects of the bushing onh-line detecting device in its design and installation,which cause the end shield grounding wire to be broken in operation,the end shield was in suspension,its electric potential was raised and the electric discharge was occurred.A new site bushing replacing method was put forward,in which the discharge of the transformer oil is not needed.By using this method,a mass of manpower and material resource was saved,and the repair time duration was shortened.