变压器空载时投切并联电容器造成设备损坏实例分析

Case Analysis of Equipment Damage Caused by Switching Parallel Capacitors During No Load of Transformer

针对新投运的330 kV/35 kV降压变电站在投入35 kV电容器期间产生谐振过电压,造成电容器和变压器损坏。通过分析保护动作情况、录波图(数据)及电容器和变压器设备现场故障现象,判断谐振过电压导致绝缘击穿是引起设备损坏的原因,提出变压器空载时不得投入电容器组,禁止空母线带电容器运行等相应改进措施。

A newly-operated 330 kV/35 kV step-down substation generates a resonant overvoltage during the input of a 35 kV capacitor,causing damage to capacitors and transformers.In this paper,by ananlyzing the protection action,the recording(data),and the filed fault phenomenon of capacitors and transformer equipment,it is judged that the resonant overvoltage causing insulation breakdown is the cause of equipment damage.The corresponding improvement measures such as no capacitor bank switching during no load of the transformer and prohibiting the operation of no-load busbars with capacitors are proposed.