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Research on unintentional off grid characteristics of microgrid

With the rapid development of renewable energy generation technology and the influence of government support policies, more and more renewable energy sources are connected to the power grid. However, due to the volatility of wind power and photovoltaic (PV) power, the proportion of high penetration rate will affect the safe and stable operation of the power grid. Microgrid is composed of distributed generation equipment, electricity load, etc. It can realize small power network with basic balance of internal power and electricity. The microgrid is required to maintain voltage and frequency stability and have secure switching function of connecting on/off grid. The transformation of microgrid from grid-connected mode to off-grid mode mainly includes intentional off grid and unintentional off grid. In this paper, studies on the technical specification of grid-connected microgrid, and establishes a grid-connected model of distributed generation. Taking 400V microgrid laboratory as an example, the model of unintentional disconnection of microgrid is established, and the simulation analysis is carried out to verify the accuracy of the model.