40.5 kV穿墙套管绝缘故障分析

Insulation Fault Analysis of Wall Bushing through 40.5 kV Cabinet

文中对某交流220 kV变电站35 kV开关柜进行多次超声波带电检测,发现多达19个开关柜有异常放电信号。根据持续复测结果以及个别开关柜解体情况,认为缺陷其产生原因是由于环氧树脂穿墙套管未使用屏蔽结构而引起的空气绝缘击穿以及其带来的固体绝缘劣化。通过穿墙套管的电场分析,确定了屏蔽体对电场分布的影响,并通过设备解体得到验证,同时给出进一步处理意见,对穿墙套管的设计及安装具有重要指导意义。

In this paper, the fault of the switch cabinet in 220 kV transformer is checked. Partial discharge (PD) signals are found in 19 switch cabinets. According to the test and disintegration results, due to the lack of internal shield in epoxy insulation, a non-uniform electric field appears in the wall bushing, resulting in air-gap discharge or breakdown. If it is operated in such situation for a long period of time, the wall bushing insulation will be aged, eventually leading to insulation break-down. The obtained analysis results may provide a reference and certain guiding significance for design and installation of the bushing and switch cabinet.