On the 110 kV outgoing feeder of 220 kV substation,there occurred a series of relay act trip caused by tree fault,which created 110 kV bus loss-of-voltage in the substation.

• 220 kV变电站110 kV出线由于树障,引起一系列保护装置动作跳闸,造成变电站110kV母线失压。