Optimal Size and Multi-objective Control of Battery Energy Storages in Distribution System with High Penetration of Distributed PV Generators

High penetration of PV into distribution system brings about side effects, such as local voltage rise because of light local loads and increase of power loss in the network. The application of Battery Energy Storages (BES) may be one of possible solutions to mitigate such side effects of PV systems. This paper presents a multi-objective optimal design and control method of BES used in distribution system with high penetration of distributed PV generators, such as smoothing the output power of PV generators, minimizing the loss in the network and peak shaving and valley filling by considering the capability of line connected with PVs, and an economic optimal model of BES sizing with maximum net income is proposed. Taking a real distribution system of 35kV with 60MW of PVs in total in China as an example, simulations are performed to test the proposed methods. The simulation results show that by the proposed optimal designed method and multi-objective control strategy has better economic performances than single objective control while the voltage of key nodes can be kept within the limits with minimized capacity of BES. The method proposed in this paper is beneficial to promote the high penetration of PV generators into power system.