一起500kV串补电容器组不平衡电流高定值旁路故障分析

Analysis of Unbalance Current High Setting Pass Fault of 500 kV Series Compensating Capacitor Bank

近期网内某500kV串补站发生了数次串补电容器组不平衡电流高定值动作导致旁路故障的情况,本文通过研究该串补站电容器组不平衡电流动作机理及保护方式,结合故障录波分析,判断故障原因及故障类型,并通过故障模拟仿真进行了验证,然后针对该故障类型特点选择极间直流电压试验成功排查出故障电容器单元,并经解体检查证实。现场实际表明,该方法可有效排查出文中提到的瞬时性恢复故障,为日后运维人员处理该类型故障提供借鉴。

Recently,the bypass faults due to several high constant of unbalanced current of capacitor banks has occurred in a 500 kV series compensating station in the power grid in China.In this paper,the cause and type of the fault are judged by way of studying operation mechanism and protection mode of unbalanced current of capacitor bank of the series compensation station in combination with fault record analysis.The verification is made by the fault simulation.Then,the fault capacitor unit is successfully detected by the inter-electrode DC voltage test in accordance with the characteristics of the fault type and verified by disassembly inspection.The actual results at site show that this method can effectively troubleshoot the transient recovery faults mentioned in the paper,and provide reference for operation and maintenance personnel to deal with this type of faults in the future.