TV爆炸事故分析及防范悬浮放电危害的措施

Analysis of TV Explosion Fault and Measures against the Damage of Suspended Discharge

减少悬浮放电对电力设备绝缘性能的影响,提高电网供电可靠性。通过分析一起220 kV SF6气体绝缘电磁式电压互感器(简称TV)爆炸事故,发现事故发生的主要原因是设备内部存在悬浮放电,引起SF6气体绝缘性能下降,在不高的雷击过电压下造成TV一次引线对地短路。通过试验室验证了悬浮放电造成设备内部电气连接不稳定,导致TV二次端电压波动,设备绝缘在线监测装置的误判断。提出防范电力设备内部悬浮放电的措施和处理对策。

The reduction of the influence of suspended discharge on the insulation performance of electric devices will improve the power supply reliability of power grid. An explosion accident of 220 kV SF6 gas insulated electromagnetic voltage transformer（TV）is analyzed,and it is found that the main reason of the accident is the suspended discharge inside the device which declined the insulation performance of SF6 gas and then caused the short circuit to ground of primary lead wire of TV under a low lightning overvoltage. The experimental test verified that the suspended discharge caused the unstable electric connections inside the device and lead to the fluctuation of TV secondary terminal voltage and the misjudgment of online device insulation monitoring equipment. Measures against the suspended discharge inside devices and treatment countermeasures are proposed.