| Microgrid cost is one of the most important factors limiting its rapid and high-quality development,and energy storage system costs account for 1/3 in microgrid total costs.Taking multi-energy AC-DC hybrid microgrid as the research object,a hybrid energy storage system structure consisting of hydrogen storage system and the battery is proposed in the dissertation to solve economical problems in microgrid.An optimized solution with HOMER Pro software is applied for the hybrid energy storage system used by minimum total net present cost as the objective function in the dissertation.The main research contents are as follows:(1)Considering uncertainty factors including wind speed,light and load on the optimal configuration of the capacity of the microgrid storage system,various distributed generation is selected in the dissertation.According to the characteristics of battery economy,high energy density,high power density and long release time of the hydrogen storage system,a hybrid energy storage system mixed hydrogen storage system with battery is developed.On the basis,a multi-energy DC hybrid microgrid structure is built based on hydrogen storage system and a mathematical model of distributed generation,energy storage system and load is established according to the existing research.(2)Considering economical and environmental protection factors of the microgrid,an objective function is proposed and constraint conditions are added in the dissertation.The objective function including the cost of environmental management and the recovery cost of residual value aims at minimizing system total net present cost.The constraint conditions consist of hydrogen storage system and battery power characteristics.Considering the reliability,economy and environmental protection factors of power supply,the evaluation index of objective function is confirmed.The objective function is made up of the loss rate of load,average energy cost and renewable energy utilization rate.(3)Microgrid in northwest China is selected as the research object in the dissertation.According to the load type and the characteristic of distributed generation,different types of distributed generation and energy storage device have been set up.The scene mode is established based on the operation strategy of the energy storage system.By using the HOMER Pro software,the total net present cost of different types of combination system have been analyzed and compared,which obtained the optimized results that is the capacity of the out-of-grid microgrid storage system.The results show that the proposed combination type can effectively reduce the total net present value of o out-of-grid microgrid system and improve the economy of microgrid.Under the condition of in-grid microgrid,the rationality of hybrid energy storage system that is made up of hydrogen storage system and battery is verified by suing HOMER Pro software and the analysis of total net present cost of the distributed generation and energy storage device.On the basis,the power price is put forward by using HOMER Pro software to obtain the optimized results that is the capacity of the in-grid microgrid storage system.The results show that it is possible to reduce the total net present cost of microgrid system and improve microgrid system economically with the use of the power price.Furthermore,through the analysis of sensitive variations,the correctness and effectiveness of the method proposed in the dissertation have been explained. |
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