一起主变低压出口真空断路器典型故障及分析

Analysis of Default with the Vacuum Circuit-breaker at Low Voltage Winding of Transformer

分析了220kV天缘变电站因主变低压出口10kV真空断路器引发的主变三侧开关跳闸故障,由于真空灭弧室存在缺陷,导致断路器在开断过程中产生重燃过电压,触头局部金属熔化;并对开关柜壳体放电,造成主变差动保护动作、三侧断路器跳闸。建议主变低压出口真空断路器严格执行有关反事故措施,强化真空灭弧室的老炼试验。

It was investigated that the operation reason for switch device of main transformer was caused by lOkV vacuum circuit-breaker at low voltage winding of the transformer in 220kV Tianyuan substation in this paper.Because of defects with vacuum arc extinguishing device,part contactor of vacuum arc extinguishing device melted and restriking over-voltage and discharge phenomena in switchgear were occurred during vacuum circuit-breaker operating. Therefore,it was proposed that vacuum circuit-breaker at low voltage winding of transformer would be carried out anti-fault measure strictly, and vacuum arc extinguishing device smelt would be tested.