换流站交流滤波器保护动作异常的分析研究

Analysis and research on protection misoperation of AC filter in the converter station

为深入诊断某±500 k V换流站切除交流滤波器时发生的小组断路器重击穿故障,就保护装置的比例差动保护动作、零序差动保护动作进行了分析研究。通过查证SER(sequence event record)报文、故障电流录波、保护录波,推定分析该小组交流滤波器的首、尾端电流互感器因暂态特性不一致导致了传动差异,引发相应的保护出口。并据此提出针对性的反事故措施,既要提高断路器设备的内绝缘能力,又要注意调整匹配首、尾端CT的二次回路及励磁特性,避免其二次输出值产生差流而导致保护误动作,以减少类似故障造成的电力系统安全隐患。

In order to diagnose the repeated breakdown fault of AC filter sub-bank circuit breaker in a ±500 kV converter station,the leading proportional differential protection and zero sequence differential protection at the moment was analyzed,and it was found that transmission difference was induced by inconsistency of transient characteristics between the initial current transformer and ending current transformer of 563 AC filter,which lead the operation of corresponding protection,through presumption of checking SER（ sequence event record） message,fault current recording,and protective recording. According to that,specific anti-accident measures are put forward,which requires improvement the internal insulation ability of circuit breaker,and in the meanwhile,attention should be paid to the matching of secondary loop and excitation characteristic in initial current transformer and ending current transformer,which is helpful for avoiding the differential value of secondary output current that will cause misoperation of the protection,in order to reduce the power system security risks caused by the similar failures.