The premise of long service life of photovoltaic power station is the quality of equipment and installation process specifications, among which, grounding is a very important step, improper grounding will be due to the equipment to the ground insulation impedance is too low or leakage flow and error, affecting the power generation. So, how should photovoltaic systems be properly grounded?

1. Component frame grounding

Many people think that the component and the bracket are metal bodies, direct contact conduction, as long as the grounding treatment of the bracket does not need to do the component. In fact, the aluminum frame of the component and the galvanized bracket or the aluminum alloy bracket have been coated, which can not meet the grounding requirements.

2, component support grounding

The lightning protection grounding resistance of the PV module must be less than 10 ohms, and the grounding resistance of the inverter and power distribution box must be less than 4 ohms. For those that cannot meet the requirements of grounding resistance, they are usually buried by adding resistance reduction agents or choosing places with low soil rates.

Second, the inverter side ground

1. Grounding the work

Generally, the working ground (PE end) is connected to the PE bar in the distribution box, and then grounded through the distribution box.

2. Grounding protection

There is a ground hole on the right side of the inverter body to do repeated grounding, protecting the inverter and the operator.

Third, distribution box side grounding

1. Lightning protection grounding

The AC side lightning protection is generally composed of fuses or circuit breakers and lightning surge protectors. It mainly protects induced lightning or direct lightning or other instantaneous overvoltage surges. The lower end of the SPD is connected to the ground bar of the distribution box

2. Grounding the box

The metal frame and base steel of cabinets, screens, platforms, boxes, and pans must be grounded (PE) or connected to zero (PEN) reliably. An open door equipped with an electrical appliance shall be connected with a yellow-green copper wire between the ground terminal of the door and the frame.

The photovoltaic system needs to ground the system from the component side, the inverter side, and the distribution box side to reduce unnecessary operation and maintenance in the later period to ensure the stable operation of the system.