保护用电压互感器二次接线方式的探讨

Discussion on secondary protection connection mode of potential transformer

给出了基于电压互感器二、三次绕组和WXH 11型微机线路保护装置电压采集电路的等效电路,通过对等效电路的分析,论述了对于电压互感器二次绕组中性线和三次绕组零线共线的接线方式,在人为或自然原因导致公用N线断线时,零序方向保护存在误动或保护灵敏度降低的可能性。

According to analyzing equivalent circuit based on secondary winding and third winding of potential transformer(PT) and voltage sampling circuit of WXH-11 micro-computer line protection device, this paper dissertates if secondary winding and third winding of PT were grounded in control room by one wire from switch yard, zero-sequence directional protection has possibility of fault operation or lower protection sensitivity when the shared wire is broken.