Active and reactive power control of battery energy storage systems in weak grids

This paper proposes outer loop active and reactive power controllers to ensure battery energy storage system (BESS) performance when connected to a network that exhibits low short circuit ratio. Inner loops control the BESS current components. The interface of BESSs with the grid is based on voltage source converters of STATCOM type which allow BESS providing not only active power control but also reactive power/voltage control. A meaningful design approach of both inner and outer loop controls is presented. Time domain simulation results show the problems encountered and the performance of the proposed control scheme.