According to different application situations, solar photovoltaic power generation system is generally divided into five kinds: grid-connected power generation system, off-grid power generation system, off-grid energy storage system, grid-connected energy storage system and multi-energy hybrid micro-grid system.
1. Grid-connected Photovoltaic Power Generation System
The photovoltaic grid-connected system consists of photovoltaic modules, photovoltaic grid-connected inverters, photovoltaic meters, loads, bidirectional meters, grid-connected cabinets and power grids. The photovoltaic modules generate direct current generated by light and convert it into alternating current through the inverters to supply loads and send it to the power grid. The grid-connected photovoltaic system mainly has two modes of Internet access, one is “self-use, surplus electricity Internet access”, the other is “full Internet access”.
The general distributed photovoltaic power generation system mainly adopts the mode of “self-use, surplus electricity online”. The electricity generated by solar cells is given priority to the load. When the load cannot be used up, the excess electricity is sent to the power grid.
2. Off-grid Photovoltaic Power Generation System
Off-grid photovoltaic power generation system does not depend on the power grid and operates independently. It is generally used in remote mountainous areas, no-power areas, islands, communication base stations and street lamps. The system is generally composed of photovoltaic modules, solar controllers, inverters, batteries, loads and so on. The off-grid power generation system converts solar energy into electric energy when there is light. The inverter is controlled by solar energy to power the load and charge the battery at the same time. When there is no light, the battery supplies power to the AC load through the inverter.
The utility model is very practical for areas with no power grid or frequent power outage.
3. Off-grid Photovoltaic Energy Storage System
And off-grid photovoltaic power generation system is widely used in frequent power outage, or photovoltaic self-use can not surplus electricity online, self-use price is much more expensive than the on-grid price, peak price is much more expensive than the trough price places.
The system is composed of photovoltaic modules, solar and off-grid integrated machines, batteries, loads and so on. Photovoltaic array converts solar energy into electric energy when there is light, and the inverter is controlled by solar energy to power the load and charge the battery at the same time. When there is no sunlight, the battery supplies power to the solar control inverter and then to the AC load.
Compared with the grid-connected power generation system, the system adds a charge and discharge controller and storage battery. When the power grid is cut off, the photovoltaic system can continue to work, and the inverter can be switched to off-grid 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 improve the proportion of self-use. The system consists of photovoltaic module, solar controller, 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 power and the grid together. When the solar power is greater than the load power, part of the solar power is powered to the load, and part of the unused power is stored through the controller.
5. Micro Grid System
Microgrid is a new type of network structure, which consists of distributed power supply, load, energy storage system and control device. The distributed energy can be converted into electricity on the spot and then supplied to the local load nearby. Microgrid is an autonomous system capable of self-control, protection and management, which can be connected to the external power grid or run in isolation.
Microgrid is an effective combination of various types of distributed power sources to achieve a variety of complementary energy and improve energy utilization. It can fully promote the large-scale access of distributed power and renewable energy, and realize the high reliable supply of various energy forms to the load. It is an effective way to realize the active distribution network and the transition from traditional power grid to smart power grid.
Post time: Feb-10-2023