Hierarchical Coordination of BESS-PV Scheduling and Droop Control With SoC Interval Management in Active Distribution Network

Flexible charging and discharging of battery energy storage systems (BESSs) and reactive power compensation of photovoltaic (PV) inverters can be coordinated to support distribution network operation. Given the feature of their rapid response, local droop control is employed to address random fluctuations of renewable outputs and loads. Therefore, this paper proposes a three-stage hierarchical coordination method of BESS-PV scheduling and droop control, aiming to minimize network power loss, voltage deviation, and operating costs. Considering capacity limitation and energy temporal coupling, an optimal state of charge (SoC) interval for one day is determined in a day-ahead stage. Then, the P-V droop control functions of BESSs and the Q-V droop control functions of PV inverters are optimized hourly, while satisfying the day-ahead SoC interval, to enable efficient real-time local control. Thus, the central day-ahead SoC interval management, the central hourly droop control function scheduling, and the local real-time droop control are hierarchically coordinated. A general model of five-segment droop control functions with reduced binary variables is introduced, and accordingly, a partial segment reduction technique and a penalized linear approximation solution method are developed. The proposed method is tested and compared with other methods. Simulation results verify its high performance in improving the network operational efficiency. © 2025 IEEE.