Battery Energy Storage System Control for Mitigating PV Penetration Impact on Primary Frequency Control and State-of-Charge Recovery

Increasing photovoltaic (PV) penetration significantly diminishes system inertia that affects systems' damping capability to regulate primary frequency control. Unlike wind turbine, PV energy system is incapable of providing under-frequency support because of no stored kinetic energy and could cause penalties for violating regulatory requirements. Therefore, a droop-type, lead-lag controlled battery energy storage system (BESS) with a novel adaptive state-of-charge (SOC) recovery strategy is proposed in this paper to provide additional damping, enhance the inertial ability of the system with 18.18% PV penetration and which satisfy Australian National Electricity Market regulatory requirements. The adaptive SOC recovery aims to maintain flexible battery SOC value according to load/PV generation forecast and comply with future events, such as peak PV generation or lower PV output during the passing cloud periods. The proposed adaptive SOC strategy regulates SOC based on the value of charging current and moreover, adaptive SOC recovery does not affect the maximum SOC limit for the regular network event. Simulation results demonstrate BESS efficacy in mitigating the adverse inertial impact of PV and accomplishing mandatory grid requirements. Moreover, the proposed adaptive SOC recovery shows the flexibility of BESS for SOC management planning in accordance with future events forecast.