一起220kV变电站并联电容器装置故障分析

Fault Analysis on Shunt Capacitor Installation at 220 kV Substation

某220 kV新建变电站并联电容器装置正常运行时发生三相多台电容器严重损坏的情况。通过对电容器装置产品质量、操作过电压、系统电压升高、合闸涌流、谐波、电容器装置保护方面对电容器装置可能出现故障的原因进行分析,认为装置与系统产生4次谐波谐振是本次故障的起因并得到谐波测试验证,中线点不平衡电流保护整定值太大是本次故障扩大的重要原因。最后提出相应建议,希望能对电容器装置的安全运行提供一定参考。

The case of serious damage of multiple units of three-phase capacitors occurred during normal operation of shunt capacitor installation at a newly established 220 kV substation. It is thought, throughout analysis of possible faults capacitors from the aspects of quality, operating over voltage, rise of system voltage, switching inrush current, harmonics and fault of capacitor protection device, that the cause of the fault is due to the 4th harmonic resonance generated between the device and the sys^e~n and is verified by the harmonic test, and the fault development is mainly caused by the big imbalance current protection settings at the neutral point. Finally, corresponding suggestions are raised with hope of providing a definite reference for the safe operation of capacitors.