一起特高压线路过电压保护断路器位置开入异常的分析

Analysis of Tripping Position Anomaly of Ultra-high Voltage Line Overvoltage Protection Circuit Breaker

某特高压线路过电压保护装置进行开入量测试时,发现两套保护装置断路器位置开入量均与现场断路器实际位置不一致。检查发现该异常由断路器位置信号未直接取断路器位置辅助接点,而是取断路器保护操作箱的跳位监视继电器辅助接点引起。当运行中出现TWJ继电器异常失电或回路接线有松动时,会引起过电压保护装置对应断路器位置不正确开入,闭锁保护,从而引发过电压保护不能正确动作。针对此种开入方式的不足,提出了保护巡视和操作时的针对性措施,建议变电站保护设计时尽量考虑过电压保护直取断路器位置辅助接点。

During the tripping test of the overvoltage protection device for a certain ultra-high voltage line,it was found that the tripping positions of both protection devices were inconsistent with actual positions of the on-site circuit breakers.Upon inspection,it was found that the anomaly was caused by position signal not directly taking the auxiliary contact of the circuit breaker position,but rather taking the auxiliary contact of the tripping monitoring relay of the circuit breaker protection operation box.If the TWJ relay loses power abnormally or the circuit wiring is loose during operation,it will cause the overvoltage protection device to open the corresponding circuit breaker incorrectly,block the tripping,and cause inaction of protection.In view of the shortcomings of this tripping method,countermeasures for protection inspection and operation have been proposed.It is recommended that when designing substation protection,overvoltage protection should be considered as much as possible by taking the auxiliary contact of the circuit breaker position directly.