55kV母线单极接地故障保护不动作问题

Protection of Fault of Single Pole Earthing of 55 kV Bus Bar

分析了牵引变电所在切除AT变压器情况下,55 kV母线发生单极接地故障时既有的各种继电保护装置均不动作的问题,并提出了3种解决办法可供选择:将AT变压器由馈线开关外侧改接到55 kV母线上;增加55 kV电压保护;新建变电所采用十字交叉主变压器。

This paper analyses the issue about the un-operation of existing various relay protection when 55 kV bus-bar is faulty under circumstances of AT transformer is being cut in traction power substation, and it raises three optional resolution methods: relocate the AT transformer from outside of feeder switch to the 55 kV bus-bar; increase the voltage protection of 55 kV bus-bar; and adopt the cross-type main transformer in new constructed power station.