一起220kV变电站电容器跳闸故障分析

Tripping Fault Analysis of Capacitor at 220 kV Substation

介绍了一起某220 kV变电站4组35 kV电容器组在运行中突然相继跳闸情况,通过分析电容器保护动作信息及故障录波图,结合电容器解体检查结果,判定电容器组跳闸原因为上级电网主变投运时空载充电造成大量的3次谐波传入电容器组回路和系统发生了部分谐振,造成谐波电流明显放大,最终导致部分元件击穿、外熔丝熔断和电容器组跳闸的后果。

In this paper, sudden tripping of 4 sets of 35 kV capacitor bank at certain 220 kV substation during operation period is introduced. Throughout analysis of protection action information and fault recorder chart of the capacitor together with the inspection result of the capacitors after disassembly, it is conducted that the tripping of capacitor bank is due to following reasons ： A large number of third harmonics caused by no load charging during switching of main transformer of up power grid is transmitted into circuit of capacitor bank and partial resonance with system is happened, causing significant amplification of harmonic current, finally leading to such consequences such breakdown of partial elements, fusing of external fuse and tripping of capacitor bank.