What are the differences between distributed PV plants and centralised PV plants?

Distributed photovoltaic power stations are generally built on the roofs of buildings, rooftops, plant roofs and vegetable sheds, making full use of space; centralised photovoltaic power stations are built in areas like the desert and the Gobi, making full use of abandoned land resources. So what are the similarities and differences between distributed photovoltaic power stations and centralised photovoltaic power stations?

Distributed photovoltaic power station and centralized photovoltaic power station of the same point.

1, the same principle, are the use of solar energy into electricity, and then the generated electricity grid-connected transmission to the grid for production and life use.

2, the same components, generally common are the use of monocrystalline silicon panels or solar thin film. Among the well-known manufacturers are Yingli, Hanergy thin film power generation.

3, the use of primary equipment is basically the same, including inverters, transformers, convergence boxes and other equipment. The role of the inverter is to convert the generated DC power into AC power; the role of the transformer is to step up the AC power converted by the inverter; the role of the sink box is to bring together the DC from the solar panels and deliver it to the inverter in a unified manner.

Distributed photovoltaic power station and centralized photovoltaic power station of different points.

1, the installation location is different: distributed PV is mainly installed on the roof of agricultural sheds, mainly concentrated in the personnel living in northern and southern China. Centralized PV is mainly installed in the Gobi and desert, generally installed in remote and desolate areas, the land is relatively cheap. Northwest of Ningxia, Gansu, Xinjiang, Qinghai and other areas are mostly.

2, grid-connected voltage levels are different: for distributed photovoltaic, generally 380V voltage to the grid, the general use of low-voltage disconnector to grid, and a distributed parallel point of the number of points depending on the actual situation, one or more. If the power station is 30 MW or less, the main transformer will not be set up, and this more 35 KV grid connection. For power stations above 30 MW generally install the main substation, after the main substation is upgraded to 110 KV voltage level and then connected to the grid.

3, the power station used by the secondary equipment is different: distributed photovoltaic power station because it is low-voltage 380V grid-connected, so for the primary equipment and secondary equipment used less. Which inverter is generally the kind of wall-mounted inverter, installation is relatively simple, small size. The transformers are also small. Commonly used are power quality monitoring, anti-islanding protection devices, fault resolution, etc. Depending on the requirements of the region, the equipment requirements and technical parameters are different. But for the time being it is a must for every distributed PV.

Centralised photovoltaic power stations have their own substations because of their high voltage level. The inverter is usually located in a substation room and is larger in size. The voltage boosting function is carried out by the box transformer, which is generally upgraded to 35 KV, and there is a wide range of equipment in the boosting station, including primary equipment such as station transformers, switchgear, various transformers, arc extinguishing coils and main transformers. Secondary equipment includes microcomputer protection, power meter, dispatch data screen, etc. It is relatively complex, and the dispatcher directly implements centralised management of the station. At the same time, the station also needs to have, power control system, etc., compared to distributed PV is much more complex.

4, the transmission distance is different: distributed PV generally speaks of the electricity sent to the grid locally, the loss of the line is very low or can be said to have no. Supplement the local electricity for local and nearby electricity users. Centralized photovoltaic power station issued electricity by high-voltage grid-connected, the electricity layer by layer when a higher voltage level, high-voltage electricity transmission to areas such as East China, in order to achieve the western electricity transmission to the east.

To sum up, there are many similarities and differences between distributed PV power stations and centralised PV power stations. However, for the time being, centralised PV power stations are slightly more difficult to grid-connect and more demanding. The prospects for distributed PV power stations are better and the amount of investment is similar for the same size of power station. And distributed photovoltaic installation is located in a more crowded area, maintenance is also more convenient.