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