| With the pressure of the energy and environmental problem brought to social gradually increased, optimizing energy structure, changes in energy production and use patterns of response measures began to receive attention. Microgird as a kind of controllable power grid with series of mechanisms, can help to improve the utilization of renewable energy sources with a reasonable dispatching4 thereby to reduce dependence on oil; the promotion and use of electric vehicles can reduce greenhouse gas emissions and automobile exhaust pollution. However, large number of electric vehicles connect to the distribution network directly for charge without control, will lead to "peak plus peak" problem, exacerbated power grid peak and valley difference, affect the stable operation of the grid. Conform to the development prospects of4 this project established a bi-level optimal dispatch for Microgird/Distribution network with battery swapping station, the main contents are as follows:Firstly, This paper introduces the operation mode of electric vehicle and its supporting facilities. Compared the advantages of the electric vehicle’s battery swapping station mode with respect to the random charge mode, And its access method in the microgird; The bi-level optimization theory as well as several common bi-level programming models are described in detail, and the application of the double layer optimization in power system is also discussed.Secondly, According to the operation model of the electric vehicle in the national power grid, an optimal scheduling model of the microgrid with battery swapping station is proposed. This operation mode takes the minimum of the power exchange between the microgrid and the distribution network as the objective function. Considering the constraints of power battery demand and battery charge and discharge rules. Described and analyzed the feasibility of the scheduling model and the actual optimization results under different distribution requirements according to the simulation results.Finally, the optimal dispatch of distribution network considering the distributed generation and the battery swapping station is studied, According to the upper and lower layers relationship between distribution network and microgrid, a bi-level optimal dispatching model of distribution network is established. The upper level takes the minimum of the power grid load square differences as the objective function, The lower level meet the charging needs of the battery swapping station in the microgird, in order to make the actual dispatching plan and the upper dispatching deviation minimum as objective function. In this model, the utilization of renewable energy can be improved and the load of distribution network was smoothed by making full use of the energy storage function of the battery. Use the improved genetic algorithm and immune algorithm to solve combinatorial optimization problems, and the validity of the model is analyzed through simulation results. |
