Lightning protection of photovoltaic power generation system: Influence of grounding systems on overvoltages appearing on DC wirings

The lightning damages increases in Photovoltaic (PV) systems because those are usually set up at the place where few tall structure around it. Therefore, it becomes important to establish lightning protection methods. When a lightning occurred near a PV system, the PV modules have the induction overvoltage due to the lightning. As a result, the power conditioner connected to the PV modules may break down due to the induction overvoltage. The overvoltage depends on the set-up conditions of each PV system and the wirings. The overvoltage must be examined on each PV system. In this paper, the overvoltage occurred in DC wirings are measured when the surge current was injected into a frame of a PV array. Furthermore, the level of the overvoltage and generation mechanisms of the overvoltage was researched.