The role of fuses in the protection of photovoltaic power plant lines.

Function of fuse

When several photovoltaic (PV) strings are connected in parallel, if a short-circuit fault occurs in one string, the other strings on the DC bus and the power grid will supply short-circuit current to the short-circuit point. Without appropriate protection measures, this will lead to the burning of PV modules, connected cables, and other equipment. It may also cause nearby debris to ignite. Several similar rooftop PV fires have occurred in China.

Fuses, connected in series in the circuit, utilize the melting property of metal to cut off the circuit when an overcurrent occurs, ensuring safe operation. As an overcurrent protection device, they are widely used in power systems, power electronics, telecommunications, rail transportation, PV power generation systems, and other new energy, industrial automation, aerospace, and military industries.

Currently, the standard solution in the PV industry is to use fuses for overcurrent protection. Fuses have become a commonly used protective device in PV power plants, widely used in combiner boxes and inverters. Major international inverter manufacturers also consider fuses as a basic component of DC protection.

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Here are some key maintenance points for photovoltaic-specific fuses

First, check the ambient temperature of the fuse's operating environment. Excessively high ambient temperatures can cause accidental melting. Second, when replacing a fuse, ensure the fuse element is installed correctly to avoid mechanical damage that could reduce its cross-sectional area and cause accidental melting. During installation, ensure the base is intact and has good contact. After installation and powering on, use an infrared thermal imager to check for overheating. Third, in areas with high radiation, regularly use an infrared thermometer or infrared thermal imager to test the temperature of the fuse and contact terminals, and address any abnormalities promptly.