Abstract: Aiming at the problem of frequent tripping of the distributed photovoltaic (PV) grid-connected boundary switch in a distribution network under non-fault conditions, the factors affecting short-term PV over-generation were analyzed. Combined with the actual operating conditions, the tripping cause of the distributed PV grid-connected boundary switch was examined in depth. It is identified that short-term PV over-generation and the mismatch between the switch setting value and the actual operating conditions are the essential reasons for the frequent tripping. An optimized setting scheme for the distributed PV boundary switch considering short-term over-generation is proposed, in which the original setting value of 1.1 times the PV rated capacity is increased to no less than 1.2 times. Based on the optimized setting and field operation, the results show satisfactory performance.