What is the relationship between distributed energy and microgrid and power station?

Power station: the traditional power grid is divided into power generation, transmission and distribution. Electric energy flows in a single phase. Large power stations generate electricity, and long-distance power grids send electricity to users. Distributed Energy: A Method of Utilizing Renewable Energy in Power Grid. Because the distribution of wind energy and solar energy is not as concentrated as that of coal mines and natural gas, large-scale wind farms and photovoltaic power stations can be built in places rich in scenic resources such as northwest China, and small power equipment such as fans, photovoltaics, energy storage and gas turbines can be connected to the user side, which saves the transmission loss in the power grid and increases the proportion of renewable energy. Here, fans, government, fuel cells and micro gas turbines become distributed power generation, and energy storage equipment is called distributed power supply. Distributed problem: Due to the appearance of user-side power supply, the traditional one-way energy flow of source-network-load becomes two-way, which leads to the new test of the established dispatching and protection strategy of power grid. In addition, the wind and scenery resources are fluctuating and random, and it is difficult to control power generation. The direct connection of distributed power sources to the power grid will eventually lead to the instability of the whole power grid.

Micro-grid: Micro-grid is a small and complete power grid with distributed power supply, its supplied load, energy conversion, protection, monitoring and other devices as a system, and uses controllable power sources such as energy storage equipment or micro gas turbines to maintain the stability of the system, so that it can absorb renewable energy such as photovoltaic and wind power. There is a point of common coupling (PCC) between the whole microgrid and the large power grid. When the power supply function of the microgrid is insufficient, it can be supplemented by the large power grid. There are two main differences between grid-connected distributed generation and direct grid-connected distributed generation: microgrid can determine the power flow direction of grid-connected points through control strategy, such as storing energy for many times during power generation and storing energy and discharging when the load is heavy; In the standard sense, microgrid can be separated from large power grid and switched from grid-connected mode to island operation mode. Whether the two modes can be seamlessly switched is a sign of the success of microgrid. In this sense, there are less than 500 microgrids in the world at present, and most of them can't realize real seamless handover. Of course, some microgrids operate in isolated islands in areas without electricity, which has no impact on large power grids. Therefore, if there are distributed power sources and loads connected to the power grid through PCC points, but they cannot be isolated, they should also be considered as distributed power sources directly connected to the power grid.