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Distributed Generation (DG) is a new style of energy use, with the advantage of low-cost , flexible way of generation, less consuming, environment friendly, etc. Assessments of a large number of DG cause certain adverse effects. Micro-grid was raised for coordinating the conflict between the grid and DG. Micro-grid combines DG, load, energy storage and control device in order to form a single controllable unit for supplying power to user. Micro-grid have unique advantages in the aspect of protecting power supply and improving efficiency of energy use, etc, however it also have some disadvantages, such as the power quality, impact to the main grid, etc. The development of energy storage technology and MAS provide a new way to solve this problem. Energy storage technology can further improve the operational characteristics and has significance of operating Micro-grid stable and efficiently. MAS has the advantages of autonomy, interactivity, efficiency, etc, and can adapt better to the coordinated control and optimization between main grid and Micro-grid.In this paper, several important types of DG in Micro-grid were introduced firstly, for instance, wind turbine generation, photovoltaic generation, fuel cell generation, energy storage etc, and their influences to grid were also analysed. Second, a mathematical model of the inverter in Micro-grid was established and the ways of controlling the inverter was also presented. On the basis of the preview work, the simulation model of wind turbine generation, photovoltaic generation, energy storage and inverter was built in PSCAD/EMTDC, focusing on simulation and analysis of the control of output of wind turbine generation and maximum output of photovoltaic generation, and the control of PQ and V/F of energy storage. By implementing DG into typical Micro-grid for analysing the dynamic operating characteristics of energy storage in grid connection mode and islanding mode, the mechanism of energy storage to the operation of Micro-grid was studied. The results of the simulation show that energy storage has important effects on supporting grid with active, reactive power quickly, adjusting V/f, stabilizing grid, ensuring Micro-grid operation stable. In addition, the three stage multi-agent control system consisting of main grid agent, Micro-grid agent and component agent was proposed in this paper, and design the control mode of component agent, then simulate to validate it in Micro-gird with energy storage.
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