低压线路保护启动和选相的改进

Improvement Scheme of Starting-up and Selecting Fault Phase in Low Voltage Power Systems

针对低压系统中利用电量的有效值进行故障相判别计算时间较长的缺点 ,提出了采用电量的瞬时值进行选相判别 ,并具体分析了瞬时值选相判别与常规选相方案的异同 .同时针对 90°接线在不同工况下发生两相短路时灵敏角变化较大的情况 ,提出了改进方案 .

In lower voltage power systems, the common scheme of selecting fault phase calculated by effective values takes much time. A new scheme of selecting the fault phase adopting the sampling value is given. The detail similarities and differences between them are presented. A proposal is put forward to improve the situation that the fitness angles of 90°martingale method have a great change when there are two phase faults in different behaviors.