基于CT拖尾电流截断算法的失灵保护延时优化研究

Research on Delay Optimization of Breaker Failure Protection Based on the CT Current Tail Truncation Algorithm

断路器失灵保护是电力系统中广泛的应用的一种后备保护。目前失灵保护动作延时较长,相应地断路器失灵后的故障切除时间也较长,系统中的部分关键节点可能失去稳定。因此,研究失灵保护动作延时优化方法,缩短断路器失灵后故障持续时间,对提高系统稳定性具有重要意义。提出了基于CT拖尾电流?短路电流判据平面的CT拖尾电流截断算法,在CT拖尾情况下能够快速截断CT拖尾电流,确保CT拖尾的情况下电流元件也能快速可靠返回,从而缩短失灵保护动作延时,无需专门配置P级CT,显著降低系统运行的风险。

Breaker failure protection is a widely used back-up protection in power system. Breaker failure protection delay is a bit longer and corresponding clear time is also longer. System stability may be lost after single phase circuit breaker failure at some important nodes. Therefore, it is very important for improving system stability to research optimization method of breaker failure protection delay and to shorten fault duration. A CT current tail truncation algorithm based on CT tailing current vs short circuit current criterion plane is shown in this paper to quickly truncate CT tailing current to guarantee current element＇s quick and reliable return even with CT tailing. This algorithm can shorten breaker failure protection delay without using P level CT, and significantly reduce system stability risk.