一起220kV SF_6断路器合闸不到位故障及分析

Failure Analysis of a 220kV SF_6 Circuit Breaker Closing Not in Place

针对贵州电网某GIS用断路器内部发生短路故障,通过解体分析发现是由于断路器主触头未接触,仅弧触头接触导致接触电阻增加,致使触头铜钨部分发热严重,在灭弧室喷口内散热不好的环境下,长时间发热累积,导致自力型动弧触头受热膨胀,在触指与静弧触头的接触部分出现间隙,引发局部的电弧烧蚀,当烧蚀产生的离子累积到一定浓度后,气室的绝缘特性被破坏,最终导致罐体对壳体发生短路放电。通过对故障相断路器进行故障排查与计算,发现是固定传动机构的螺栓松动致使断路器合闸不到位,最终导致断路器发生短路放电。文中定性的说明了造成螺栓松动的原因,并提供了螺栓防松动的改进措施。

A short circuit fault occurred in a GIS circuit breaker in Guizhou Power Grid. Through the disintegration analysis, it is found that the circuit breaker is not in the position of closing the arc-extinguishing chamber, the main contact is not touched, and only the contact of the arc contact causes the contact resistance to increase, causes the copper tungsten part of the serious heated, while the heat dissipation in the nozzle environment is not good, longterm heat accumulation, resulting in self-expansion of the arc-type contact after contact with the static＇, arc contact part of the gap, resulting in local arc ablation. When the ions generated by ablation accumulated to a certain concentration, the insulation properties of the gas chamber is destroyed, resulting in short-circuit between the tank and the shell. Through the trouble shooting and calculation of the faulty circuit breaker, it is found that the loosening of the bolts of the fixed transmission mechanism causes the circuit breaker to close in the wrong place, which leads to the short circuit discharge of the circuit breaker. The causes of the looseness of the bolts are qualitative described and the improvement measures of anti-looseness of the bolts are provided.