According to the electrical installation safety regulations, the metal frame of the photovoltaic power generation device with the metal frame module must be grounded. If the insulation of the DC side and the AC side of the inverter is not particularly strengthened, the grounding of the frame is more important.
The outer frame of the photovoltaic device is generally made of aluminum alloy. Since the grounding wire and the surrounding will form a closed loop, if a lightning strike occurs nearby, it is very likely to generate a high induced voltage.
Therefore, small gaps are often set in the closed loop of the ground grid. For example, the photovoltaic unit and the module are insulated, and the electronic circuit of the inverter is also insulated from the ground terminal. When a lightning strike occurs nearby, all or part of the induced voltage will be added to the gap. At this time, the overvoltage will cause damage to the module or inverter or even cause a fire.
One is to ensure proper grounding design
In this way, most components of the lightning current can be reduced by flowing through the main DC conductor and the non-linear resistor (SPD).