220kV典型保护死区问题的探讨

Discussion about the problem of 220kV typical protection's dead-zone

针对220kV断路器只在一侧装设一组CT的现状,简要分析了目前典型保护死区的常规动作逻辑及其存在问题,研究了在断路器两侧各装设一组CT的条件下,通过两侧保护加入低电压闭锁功能,分段跳开相应断路器的动作机理。在此基础上提出了消除保护死区的解决方法,即在断路器两侧各装设一组CT的基础上,两侧保护加入低电压闭锁功能,分段跳开相应断路器切除死区故障。此法在一定程度上能够有效降低事故影响范围。

In view of the actual situation which CT is only installed on 220 kV circuit breaker side, existing problems and the action logic of common protection＇s dead-zone are briefly analyzed. The operation mechanism of related circuit breaker tripping in divided period under the condition of CT fixed on both sides respectively and side＇s protection added with the function of low voltage blocking, is also researched. Based on it, ways to eliminate protection＇s dead-zones are put forward, i.e. CT is fixed on each side whose protection added the function of low voltage blocking, and corresponding circuit breaker is segmently tripped to resect dead-zones fault. To some extent, the methods can effectively reduce the influence scope of accidents.