Distributed PHOTOVOLTAIC power stations are generally built on the roof, roof, plant roof and vegetable greenhouses, making full use of space; Centralized pv plants are built in desert and gobi areas to make full use of abandoned land resources. So what are the similarities and differences between distributed photovoltaic power stations and centralized photovoltaic power stations?
Similarities between distributed photovoltaic power station and centralized photovoltaic power station:
1, the principle is the same, is the use of solar energy into electricity, and then the generated electricity is connected to the grid to the grid for production and life use.
2, the components are the same, generally common use of monocrystalline silicon panels or solar film. Among the famous manufacturers are Yingli, Hanergy Thin Film power generation
3, the use of primary equipment is basically the same, including inverter, transformer, bus box and other equipment. The role of the inverter is to generate direct current into alternating current; The function of the transformer is to boost the alternating current converted by the inverter; The function of the sink box is to collect the DC of the solar panel together and deliver it to the inverter uniformly.
Differences between distributed photovoltaic power station and centralized photovoltaic power station:
1. Different installation positions: distributed photovoltaic is mainly installed on the roof of agricultural greenhouses, mainly concentrated in north and South China where people live. Centralized pv is mainly installed in the Gobi and desert, generally in remote and desolate areas, the land is cheaper. Ningxia, Gansu, Xinjiang, Qinghai and other regions in the northwest are in the majority.
2, the grid voltage level is different: for distributed photovoltaic, generally 380V voltage is connected to the grid, the general use of low-voltage tripping device to connect to the grid, and the number of a distributed dot depends on the actual situation, one or more. The grid-connected voltage of the centralized photovoltaic power station is generally 35KV or 110KV. If the power station is 30 mw or less, the main transformer will not be set up generally, which is more than 35KV connected to the grid. For power stations over 30 MW, the main transformer is generally installed and connected to the grid after rising to 110KV voltage level through the main transformer.
3. The secondary equipment used by the power station is different: the distributed photovoltaic power station is grid-connected at low voltage 380V, so it uses less primary equipment and secondary equipment. The inverter is generally the kind of wall-mounted inverter, installation is relatively simple, small size. Transformers are also small transformers. Commonly used are power quality monitoring, anti-island protection device, fault resolution and so on. The requirements for equipment and technical parameters vary depending on the region. But for now it is a must for every distributed pv device.
Centralized photovoltaic power stations generally have their own substations because of their high voltage levels. The inverter is generally located in the sub-station room, the body is larger. The boost function is completed by the box transformer, generally up to 35KV. There are more equipment in the booster station, including station transformer, switch cabinet, various transformers, arc suppression coil, main transformer, etc. Secondary equipment has microcomputer protection, electricity meter, scheduling data screen, etc. Relatively complex, dispatching directly centralized management of the power station. At the same time, the station also needs to have, power control system, etc., which is much more complicated than distributed photovoltaic.
4, the transmission distance is different: distributed photovoltaic power is generally connected to the local grid, the loss of the line is very low or can be said to have no. Replenish local electricity supply for local and nearby customers. The electricity from the centralized photovoltaic power station is connected to the grid through high voltage, and the electricity is transmitted layer by layer to the higher voltage level, and the high voltage is transmitted to east China and other regions, so as to realize the west-east power transmission.
To sum up, there are many similarities and differences between distributed photovoltaic power station and centralized photovoltaic power station. However, for now, it is a little more difficult for centralized photovoltaic power station to be connected to the grid, and the requirements are relatively high. The prospects for distributed pv power stations are good, and the amount of investment for plants of the same size is similar. And the location of distributed photovoltaic installation is more personnel zone, maintenance is also more convenient.
