Abstract: Automatic reclosing is an important measure to ensure the safe and stable operation of power system. This paper analyzes an abnormal event of the second set of line protection reclosing charging lamp on 220 kV line, based on the input node diagram and wiring schematic diagram of the protection device, it is found that position relay has no excitation action after closing. Comparing the relevant operation circuit drawings with the actual on-site wiring, it is determined that the root cause is the incomplete manual opening and closing circuit of the second set of protection device operation box, resulting in the reclosing discharge caused by the input of "locking reclosing". Combined with the relevant requirements, the rectification suggestions are put forward, and the analysis results can provide an effective reference for the treatment and prevention of similar hidden dangers.