According to different applications, solar photovoltaic power generation system is generally divided into grid-grid power generation system, off-grid power generation system, off-grid energy storage system, grid-grid energy storage system and various energy hybrid micro-grid system
1. Grid-connected photovoltaic power generation system
The photovoltaic grid-connected system is composed of photovoltaic modules, photovoltaic grid-connected inverter, photovoltaic electricity meter, load, two-way electricity meter, grid-connected cabinet and power grid. The photovoltaic module generated by the light is converted into AC power through the inverter to supply the load and sent to the power grid. There are two main modes of grid-connected photovoltaic system, one is “self-use, surplus power Internet access”, and the other is “full Internet access”.
The general distributed PHOTOVOLTAIC power generation system mainly adopts the mode of “self-use, surplus power online”, the electricity generated by solar cells is given priority to the load, when the load is not exhausted, the excess electricity is sent to the power grid. When the load supply is not enough, the power grid and photovoltaic system can supply power to the load at the same time.
2. Off-grid photovoltaic power generation system
The off-grid photovoltaic power generation system does not rely on the power grid and is generally used in remote mountainous areas, unpower areas, islands, communication base stations and street lights, etc. The system is generally composed of photovoltaic modules, solar energy controller, inverter, storage battery, load and so on. The off-grid power generation system converts the solar energy into electric energy with light, supplies the load through the solar-controlled inverter and charges the battery, and supplies the ac load through the inverter without light.
For areas without power grid or frequent power failure areas, the practicality is very strong.
3. And off-grid photovoltaic energy storage system
And off-grid photovoltaic power generation system is widely used in places where frequent power failure, or photovoltaic self-use can not be used to the Internet, the self-use electricity price is much more expensive than the on-grid electricity price, and the peak electricity price is much more expensive than the trough electricity price.
The system is composed of photovoltaic modules, solar energy and off-grid integrated machine, storage battery, load and so on. The photovoltaic array converts solar energy into electric energy with light, supplies the solar energy control inverter and charges the battery. When there is no light, the battery supplies power to the solar energy control all-in-one inverter, and then to the AC load.
Compared with the grid-connected power generation system, the system adds a charge and discharge controller and battery. When the power grid is out, the photovoltaic system can continue to work, and the inverter can be switched to the off-grid working mode to supply power to the load.
4. Grid-connected energy storage photovoltaic power generation system
Grid-connected energy storage photovoltaic power generation system can store excess power generation and increase the proportion of self-use. The system is composed of photovoltaic modules, solar energy controller, storage battery, grid-connected inverter, current detection device, load and so on. When the solar power is less than the load power, the system is powered by the solar energy and the grid. When the solar power is greater than the load power, part of the solar power supplies the load, and part stores the unused electricity through the controller.
5. Microgrid system
Microgrid is a new type of network structure, which is composed of distributed power supply, load, energy storage system and control device. The distributed energy can be converted into electricity and then supplied to local loads nearby. Microgrid is an autonomous system that can realize self-control, protection and management. It can be connected to the grid with the external power grid or run in isolation.
Microgrid is an effective combination of various types of distributed power supply to realize multiple energy complementarity and improve energy efficiency. It can fully promote the large-scale access of distribution power supply and renewable energy, realize the high reliable supply of various energy forms, and is an effective way to realize the active distribution network, and is the transition from traditional power grid to smart grid.
