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In order to adapt to the actual situation of power distribution system fault recovery with micro-grid, a recovery strategy for micro-grid to operate on island with important system load at first under fault conditions is hereby studied. Due to the weak overload capacity, large fluctuation and obvious influence of weather and time period of renewable energy in micro-grid, the dynamic changes of distribution generation and loads in non-fault power loss areas should be considered as much as possible when generating islands. According to historical data, the daily random fitting functions of photovoltaic power generation, fans and various loads are respectively generated by using respective optimization models. For judging the start and duration of the fault, using the fitting function to set the fitting power value of each unit in the distribution system and other information, and calculating the dynamic importance information of each load node as the heuristic condition for subsequent island search. The search strategy in this paper is to guide the load added to the island according to the dynamic importance of the load, and to analyze the reliability of island operation. This method controls the direction of island search, and gives priority to ensuring the recovery of important loads. At the same time, it can ensure the balance between the stability of island generation and the maximum utilization of renewable energy.

With the development of China’s comprehensive construction and the upgrading of industrial system, China began to transform from energy-consuming and high-pollution society to energy-saving and environment-friendly society. Knowledge-intensive and equipment-intensive industries are on the increase, which causes the increasing demand for the stability of electricity supply. At present, the problem of transmission over distribution still exists in the power grid construction of China. In power systems over 110 k V, the strategy of non-homologous dual power supply is adopted to guarantee power supply. When a circuit trip occurs, the spare line can be used to continue the power supply, so the existing domestic main network system has a high reliability. The main function of the distribution network system is to connect the user and the main network, which is an important link of power transmission. In the future of the development of intelligent power network, the original parts such as mobile voltage transformer and current transformer can be used to locate the fault position after the physical fault occurs in the distribution network, and automatic reclosing device can be used for fault isolation and fault recovery. How to use the optimal strategy to make the controllable automatic reclosing device be used for switching operation after the physical failure of the distribution network so as to ensure the reliable power supply of the distribution network, has become the focus of power network hoisting service.