一起500kV断路器均压电容器故障分析

Analysis on a Fault of Grading Capacitor for 500 kV Circuit Breaker

对某换流站一起500 kV断路器均压电容器在断路器分闸时发生放电击穿的故障进行分析,依据现场检查情况、故障录波情况、返厂解体检查情况及相关试验数据,对均压电容器击穿原因展开判断分析,并对绝缘筒击穿及碳化的原因进行了探讨。经分析,该次故障发生的原因为在断路器分闸的过程中的操作过电压及较大的放电电流引起了均压电容器的击穿;此外,对直流站控系统存在的逻辑问题提出了处理意见。针对该故障,提出改进措施,以提高设备的运维可靠性。

A discharge breakdown fault of grading capacitor of 500 k V circuit breaker in a converter station, which occurred in breaker opening process, is analyzed. According to the field inspection record,the fault waveform record, the recall-checking record and the test data, the cause of the breakdown of grading capacitor, as well as the cause of the breakdown and carbonization of the insulating cylinder, is investigated. The results show that the operating overvoltage and discharge current in the process of breaker opening resulted in the breakdown fault. Some countermeasures against the logical problem in DC station control system are put forward, and some improvement approaches are suggested in order to improve the reliability of operation and maintenance of the electrical equipment.