If line-type metal oxide surge arresters are installed on the lines, it can prevent insulator flashover and reduce the number of tripped outages. The solution is to parallel line-type metal oxide surge arresters beside the insulator string. When the potential of the tower arm rises, the residual voltage of the arresters is lower than the flashover voltage of the insulator string, which can ensure that the insulator no longer flashes over and avoids the tripping and power outage of the line.