| With the increasing consumption of fossil energy,new energy power generation technology has attracted wide attention from all walks of life.As the carrier of distributed generations,microgrid has created enormous economic benefits for the society with its advantages of flexible operation,safety and reliability,and high energy utilization.With many kinds of distributed generations being put into the microgrid,the key problem in the planning stage of microgrid is to rationally allocate the capacity of distributed generations and meet the corresponding indicators of microgrid.In addition,with the continuous improvement of microgrid control technology,some controllable loads will be involved in the operation of microgrid in the future,thereby weakening the impact of uncertainty of wind and solar output on the operation of microgrid.Considering the demand response,this paper optimizes the capacity of distributed generations in microgrid.The main research contents are as follows:Firstly,the structure of microgrid system with multiple distributed generations is built,and the power output models of wind turbine,photovoltaic,battery and diesel generator are studied.Considering the constraints of power supply reliability and distributed generation itself,a capacity optimization model of microgrid is constructed,which takes into account the economic cost,environmental protection cost and penalty cost of energy waste,and the weights of various indicators in the total objective function are determined by analytic hierarchy process(AHP).The microgrid operation strategy of improved load-following is adopted to give full play to the advantages of energy storage devices.Secondly,aiming at the shortcomings that the gravitational search algorithm is easy to deviate from the optimal solution,the improved gravitational search algorithm is used to optimize the capacity of the microgrid under wind-solar-storage,wind-solar-diesel and wind-solar-diesel-storage power supply modes respectively.The results show that the wind-solar-diesel-storage mode is more advantageous.Sensitivity analysis is carried out on power supply reliability,battery discharge depth,diesel price and penalty coefficient of energy waste of microgrid,and the effectiveness of the proposed algorithm is verified by comparing with other algorithms.Finally,according to the demand response model,demand response strategy and optimization algorithm are used to solve the load curve after load transfering,and the capacity optimization model of microgrid is adjusted.The optimization results of three power supply modes before and after demand response are compared.The changes of each index of microgrid under different levels of transferable load participation are analyzed,and the changes of microgrid operation and battery SOC before and after demand response are analyzed.The results show that the participation of demand response improves the ability of microgrid to cope with the uncertainty of wind and solar output,and can improve various indicators of microgrid in varying degrees. |
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