Abstract: ABSTRACT: In the power system, due to the single power supply point of the local power grid, and the small power supply running on the grid, it is difficult to coordinate the setting of relay protection, resulting in the failure of the line protection reclosing device to operate normally. Combined with the production practice, this paper analyzes a high-voltage side insurance fault of 35kV substation transformer and the unsuccessful action of 35kV line protection reclosing, and puts forward the rectification suggestions of protection setting and device function configuration, and takes lightning protection measures to improve the safe and stable operation of local power grid.