Distributed photovoltaic power generation refers to the configuration of a smaller photovoltaic power supply system at the user site or near the power site to meet the needs of specific users, support the economic operation of the existing distribution network, or meet the requirements of both aspects. Distributed photovoltaics are often built in places like building roofs, factory roofs, and vegetable sheds to make the most of space.

Similarities between distributed photovoltaic power generation and centralized photovoltaic power generation

1. The principle is the same, both use solar energy to convert it into electrical energy, and then connect the generated electrical energy to the grid and send it to the grid for production and living use.

2. The solar panels are the same, usually using monocrystalline silicon panels or solar thin films.

3. The main equipment used is basically the same, including solar inverters, transformers, combiner boxes and other equipment. The function of the inverter is to convert the generated direct current into alternating current. The function of the transformer is to enhance the alternating current converted by the inverter. The function of the combiner box is to collect the DC power from the solar panels, and then bring them together in one place and fuse them for unified delivery to the inverter.

The difference between distributed photovoltaic power generation and centralized photovoltaic power generation

1. Different installation locations: Distributed photovoltaics are mainly installed on roofs, mainly in North and South China where people live. Concentrated photovoltaics are mainly installed in the Gobi and desert.

2. Different grid-connected voltage levels: For distributed photovoltaics, 380V is usually connected to the grid, and a low-voltage release is usually used to connect to the grid, and the number of distributed grid-connected points depends on the actual situation. The grid-connected voltage of the centralized photovoltaic power station is usually 35KV or 110KV. If the power of the power station is less than or equal to 30 MW, there is usually no main transformer and such a grid over 35KV is connected to the grid. For power stations above 30 MW, the main transformer is usually installed, and the main transformer is upgraded to 110KV voltage level and then connected to the grid.

3. The secondary equipment used in the power station is different: because the distributed photovoltaic power station is a low-voltage 380V grid-connected equipment, it is less used for primary equipment and secondary equipment. Among them, the inverter is usually a wall-mounted inverter, which is relatively simple to install and small in size. Transformers are also that kind of small transformers. Commonly used microcomputer protections include power quality monitoring, anti-islanding protection devices and fault decoupling.

According to regional requirements, equipment requirements and technical parameter requirements are also different. But at present, anti-islanding protection device is a must-use device for every distributed photovoltaic. Concentrated PV plants usually have their own substations due to their relatively high voltage levels. The inverter is usually located in the substation room and has a larger size. The boost function is completed by replacing the box, usually up to 35KV. There is a lot of equipment in the booster station.

The main equipment includes power station transformers, switch cabinets, various transformers, arc suppression coils and main transformers. Secondary equipment includes microcomputer protection device, watt-hour meter, scheduling data screen, etc. The more complex dispatch directly realizes the centralized management of the power station. At the same time, the station also needs a power prediction system and a power control system, which is much more complicated than a distributed photovoltaic system.