Optimal Locating and Sizing the Energy Storage System Considering the Reconfigurability of the High Voltage Distribution Network in Urban Grids

In some of the China’s urban grid, the transmission congestion problems are usually mitigated by reconfiguring the topological structure of the high voltage distribution network (HVDN). Whereas the growing amount of the electric vehicles (EV) and the large scale photovoltaic (PV) generations that integrate to the grid result in the frequent reconfiguration of the HVDN. However, the development of the energy storage technology provides an efficient method to handle this problem. But the high cost of the energy storage devices and the limited installation room for large scale energy storage systems (ESS) are still a tricky problem. Thus the size and the location of the ESS should be elaborately selected. In order to fully exploit the advantages of the ESS, this paper proposed a two-layer ESS planning model which considered the coordination scheme of the charge and discharge strategy of the ESS and the HVDN reconfiguration. The optimal size and location of the ESS is determined in the upper layer model. The lower level model is used to calculate the operation cost which can be considered as the adaptability of the decision produced by the upper layer model. The two layer optimization model is solved by the NSGA-II algorithm. A testing system extracted from an urban grid in China is used to verify the validity of the proposed method. Numerical results shows that with the assistant of the ESS control scheme, the reconfiguration times of the HVDN is significantly reduced while the reconfigurability of the HVDN is also conducive to save the investment on ESS.