Lightning Protection Design of Independent Photovoltaic Power Station

1. The main parts of independent photovoltaic power plants vulnerable to lightning

An independent photovoltaic power station is mainly composed of a square array of solar cells, a controller, an inverter, a battery pack, an AC power distribution cabinet, and a low-voltage overhead output line. Independent photovoltaic power plants are vulnerable to lightning strikes in two places: solar panels and computer rooms.

The battery panel is composed of a vacuum tempered glass interlayer and a surrounding aluminum alloy frame, which is connected to the metal bracket.

The battery panel is susceptible to a direct lightning attack as well as an induced lightning attack. There are controllers, inverters, AC power distribution cabinets, and other electrical equipment in the computer room, which are susceptible to the intrusion of induced lightning and lightning waves;

In addition, under the action of thunder and lightning, thunder and lightning waves may also invade the equipment room, endanger personal safety, or damage equipment. A severe lightning attack will cause great damage to the entire independent photovoltaic power station.

Independent photovoltaic power plants have a huge investment, and lightning protection of power plants is very important. When designing the system for lightning protection, comprehensive protection must be achieved, which must be economical and reasonable, but also safe and effective to ensure the safety of independent photovoltaic power plant equipment.

2. Design of lightning protection device for independent photovoltaic power station

Lightning rods are the main device to protect against direct lightning damage and are widely used in general civil buildings. The "Code for Design of Lightning Protection for Buildings" has clear regulations on whether to install lightning rods in non-construction industrial open-air sites: when the expected number of lightning strikes in the site N≥0.06 times/independent lightning rods should be installed to prevent direct lightning strikes.

According to basic data such as the average annual number of thunderstorm days in the area where the independent photovoltaic power station is located in Qinghai Province and the area of solar cell arrays, the estimated annual number of lightning strikes for the solar cell array in different regions N<0.06 times/a is calculated. Perform direct lightning protection.

For protection against induced lightning and lightning waves, lightning arresters are selected in the project. A lightning arrester is a kind of protective equipment used to limit lightning overvoltage (or internal overvoltage caused by operation) along the line.

3. Grounding device of the independent photovoltaic power station

The function of the grounding device of the independent photovoltaic power station is to dissipate the lightning current to the earth as soon as possible. The grounding device includes the grounding body, the grounding wire, and the grounding lead-in. The requirement for the grounding device is to have a sufficiently small grounding resistance and a reasonable layout. Buried steel pipes, angle steel, or reinforced concrete foundations can all be used as grounding electrodes.

The above information is provided by a renewable power system installation company.