In recent years, due to improper selection of DC switches, photovoltaic power plants have caused overheating, leakage and sparks, and even fires have occurred in the power station in severe cases. Cost, the quality of the DC switch is not strictly controlled, resulting in increased risk of electric shock and fire accidents.

Small parameter differences may have a big impact

When selecting DC switch products, inverter manufacturers usually preliminarily estimate and ensure sufficient margin through key parameters, and then select suitable products and specifications according to the on-site environment.

For example, the turn-off capability is an important parameter to measure in the selection of DC switches. This is because the disconnection voltage and current are relatively high in the photovoltaic system. Once there is a ground fault, the high short-circuit current will pull the contacts together, thereby This results in extremely high short-circuit currents, up to a maximum of kiloamperes. Therefore, the requirements for the arc extinguishing capability of the DC switch in the photovoltaic system will be higher.

At present, the common DC switches on the market have a cut-off capacity of more than 3ms.

In the selection of DC switches, in addition to the comparison of product parameters and the necessary sample testing, users usually also evaluate the manufacturers and suppliers of components and raw materials.

The importance of DC switches in photovoltaic power plants is self-evident. Therefore, users and inverter manufacturers should pay attention to details in the selection. The selection of photovoltaic DC switches should first estimate the key parameters and ensure sufficient margin. Then select suitable products and specifications according to the on-site environment, and at the same time, it is best to verify whether the product parameters can meet the actual needs through experiments. Second, carefully inspect the DC switch manufacturers, such as whether they are implemented in accordance with ISO related standards, how the production line is, and how the quality management is. In addition to the necessary sample simulation testing, it is also necessary to evaluate the manufacturers and suppliers of components and raw materials.