Solar PV DC Fuses
May 13, 2022
Solar PV DC Fuses
DC fuses are used as protection components on the DC side of photovoltaic power plants, and there are certain differences in each design scheme. This paper first describes the protection principle and application of fuses, and puts forward the parameter configuration requirements of photovoltaic DC fuses in combination with the technical requirements of various standards. Then, combined with the current international mainstream design schemes and equipment schemes, the existing problems and advantages are expounded. It is concluded that the configuration of DC fuses plays a pivotal role in ensuring the safe and reliable operation of photovoltaic power plants and is indispensable.
On the DC side of the photovoltaic power station, according to the configuration of the photovoltaic inverter scheme, multiple strings are connected in parallel to the DC combiner box (central inverter scheme) or string inverter (string inverter scheme) of the DC bus.
When several PV strings are connected in parallel, such as a short-circuit fault in one string, other strings on the DC bus and the grid will provide short-circuit current to the short-circuit point. If the corresponding protection measures are lacking, the photovoltaic modules, the cables connected to them and other equipment will be burned. At the same time, it may cause the burning of attachments near the equipment. At present, there are many similar roof photovoltaic fire accidents in China, so it is necessary to install protective devices in the parallel circuit of each string to enhance the safety of photovoltaic power plants. At the same time, the standard IEC62548 [1] also has clear requirements for the overcurrent protection of the DC side of photovoltaic power plants.
Based on this, in the design scheme of photovoltaic power plants, DC fuses are often connected in series in each parallel string circuit.
