DERs Sizing of Hybrid Microgrid by Hierarchic Optimization Strategy

Optimal sizing of distributed energy resources is of great importance to enhance the reliability and economic performance of microgrid. In this paper, multiple objective functions are employed to determine the optimal capacity, including the utilization rate of renewable energy, economic performance, and reliability of the system. The capacity optimization is transformed into two parts by using hierarchic optimization strategy. The first part is to calculate the rough capacity range of wind, PV, storage and diesel generator. The mixed integer programming is employed to solve the problem, taking the minimum capacity of energy storage and diesel generator as the objective function. The second part is to seek the best capacity through the rough capacity range. The capacity configuration scheme is obtained by optimizing the cost and operation of hybrid microgrid. The method is used in an example microgrid, the results show that the model can get the optimal capacity guaranteeing the reliability and economy of the system, and the utilization rate of renewable energy is improved.