The Capacity Configuration of Energy Storage System in DC Microgrid with Source-storage Integration

Abstract

The occurrence of a fault in a DC microgrid can significantly jeopardize the system’s safe operation, making it a critical area of research for scholars. One key focus of this research is on developing methods to suppress the fault current, which has become a research hotspot for many scholars. Each distributed power source is connected to DC microgrid through a battery storage system to form a source-storage integration DC microgrid structure, which can have good fault current control ability and obvious improvement effect on reducing the protection technology difficulty of DC microgrid and enhancing the flexibility of distribution network. Compared with the traditional DC microgrid structure, the source-storage integration DC microgrid, whose battery storage system is changed from centralized to distributed, will smooth fluctuations in distributed power output by modifying energy storage planning principles, and also maintain bus voltage and realize fault current control with distributed power sources. Capacity planning principles for energy storage systems proposed in this paper were studied for DC microgrids with source-storage integration, and the total energy storage capacity and power under two DC microgrid structures were compared and analyzed with a scenic complementary power station as an example. Although a DC microgrid with a changed grid structure would require less than a 20% increase in the overall capacity and power of the energy storage system, according to the calculation results, the operation of the microgrid can be significantly improved, the flexibility of power dispatching of the distribution network was enhanced, and the investment cost of fault protection was reduced. Research into the capacity configuration of energy storage systems has demonstrated that DC microgrids with integrated source and storage capabilities hold significant engineering application value and practical significance.