1.Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology, Ministry of Education (Northeast Electric Power University), Jilin 132012, China;2.Ganzhou Power Supply Company of State Grid Jiangxi Electric Power Co., Ltd., Ganzhou 341000, China

Aiming at the problem of insufficient charging and discharging frequency regulation capability of battery energy storage system (BESS) when state of charge (SOC) is low or high, this paper proposes a primary frequency regulation control strategy of BESS considering SOC recovery. In the frequency regulation stage, based on the S-type function, the construction method of auxiliary frequency regulation control and the calculation method of frequency regulation coefficient of BESS are put forward, and the power system frequency is controlled by the frequency regulation coefficient of BESS, so as to realize the recovery of SOC and the improvement of charging and discharging frequency regulation capability of BESS when SOC is low or high. In the SOC recovery stage, by comprehensively considering the demand of SOC recovery and the limitation of power grid operation state, the appropriate output control strategy for SOC recovery is adopted. Simulation analysis verifies that the proposed strategy can recover SOC to a better state faster, solve the problem of insufficient charging and discharging frequency regulation capability of BESS when SOC is low or high to a certain extent, and effectively improve the frequency regulation effect and the SOC recovery effect.