Microgrid definition The micro-grid (Micro-Grid) is also translated into a micro-network, which is a new type of network structure, which is a system unit composed of a set of micro-power, load, energy storage system and control device. The microgrid is an autonomous system that can achieve self-control, protection and management. It can be operated in parallel with the external grid or in isolation. The microgrid is a concept compared to the traditional large power grid. It refers to a network of multiple distributed power sources and their associated loads according to a certain topological structure, and is connected to the conventional power grid through static switches. The development and extension of the microgrid can fully promote the large-scale access of distributed power and renewable energy, and achieve high and reliable supply of multiple energy sources. It is an effective way to realize active distribution network. Smart grid transition. Microgrid composition The microgrid refers to a small power distribution system that is a collection of distributed power sources, energy storage devices, energy conversion devices, related loads, and monitoring and protection devices. The power sources in the microgrid are mostly distributed power sources with small capacity, that is, small units containing power electronic interfaces, including micro gas turbines, fuel cells, photovoltaic cells, small wind turbines, and energy storage devices such as supercapacitors, flywheels, and batteries. They are connected to the user side and have the characteristics of low cost, low voltage and low pollution. Figure microgrid control system (composed of photovoltaic modules, photovoltaic controllers, fans, fan controllers, battery packs, inverters, AC loads and DC loads) Relative to the power system, the microgrid is similar to a separate control unit, each of which has a sophisticated plug-and-play function. For each micro power supply, the most critical is its own interface, control, protection and voltage control of the microgrid, power flow control and maintain its operational stability. An important function is the smooth transfer between the networking operation of the microgrid and the operation mode of the island. In the microgrid, in order to prevent the impact of the microgrid and the distribution network on the internal load of the microgrid, the power distribution structure of the microgrid needs to be redesigned, and the unimportant load is connected to the same feeder, important or sensitive. The load is connected to another feeder. Distributed power supplies, energy storage components and corresponding control, regulation and protection devices are installed on the feeders connected to the sensitive load. In this way, when the microgrid and the main network are unpacked, some unimportant loads can be removed by the isolation device, but normal and continuous operation of some important loads can still be guaranteed. The microgrid has functions such as control, coordination, and management, and is implemented by the following systems. (1) Micro power supply controller The micro power grid mainly relies on the micro power supply controller to adjust the feeder power flow, the bus voltage level and the solution of the main network, and the grid operation. Due to the pull-and-plug function of the micro power supply, the control relies mainly on the local signal and the response is on the order of milliseconds. (2) Protection Coordinator The saturation coordinator is applicable to both the fault of the primary network and the failure of the microgrid. When the main network fails, the protection coordinator should isolate the important load in the microgrid from the main network as soon as possible. In some cases, the important load in the microgrid allows the voltage to sag for a short time. After taking certain compensation measures, the microgrid can not be separated from the main network. When a fault occurs in the microgrid, the protection should isolate the fault segment to the smallest possible extent. (3) Energy Manager The energy manager schedules the system according to the preset values ​​of voltage and power, and the corresponding time is minute. Gfci Receptacle Outlet,Gfi Electrical Outlet,Gfci Protected Outlet,Outdoor Gfci Outlet Lishui Trimone Electrical Technology Co., Ltd , https://www.3gracegfci.com
Microgrid structure
