Abstract: The development of microgrid is an important way for rational utilization of renewable energy. Energy storage system (ESS) plays an important role in the process of coordinating multiple energy sources and achieving efficient collaborative optimization of microgrid. An optimal load dispatch model is constructed for microgrid, in which both distributed and centralized energy storage systems are considered. And demand response (DR) are considered in the proposed model. The proposed optimal load dispatch model comprehensively considers the economic cost and stability of the microgrid, thereby ensuring the stability of the microgrid while reducing the economic cost of the microgrid at same time. The proposed optimization problem is formulated as a mixed integer linear programming (MILP) problem, which is solved efficiently using commercial solver CPLEX. In the experimental part, the impacts of different ESSs and DR on the economic cost and stability of the microgrid load dispatch process are discussed. The results show that the microgrid with distributed energy storage systems and centralized energy storage system can effectively reduce the economic cost of the microgrid and improve the stability of the microgrid. And the results reveal that the implementation of DR can further reduce the economic cost and improve the stability of microgrid. In addition, the experiment deeply explores the impact of the economic cost and stability weight factors on the objective function. The results show that the selection of the weight factors is a trade-off between the economy and stability of the microgrid, the best compromise between economic cost and stability is calculated in this paper. The research in this paper has important practical significance for the economic and stable operation of microgrid with distributed and centralized energy storage systems.

Key words: microgrid; optimal load dispatch; distributed energy storage systems; centralized energy storage system; demand response