Coordinated Control Method of Thermal Power-Hybrid Energy Storage System

With the increasing proportion of renewable energy sources into the power grid, thermal power units are more and more frequently involved in grid frequency regulation. To solve the problem of insufficient secondary frequency regulation capability for thermal power units, this paper utilizes a hybrid energy storage system (HESS) consisting of both flywheel energy storage (FES) arrays and lithium-ion battery energy storage (BES) arrays to assist the secondary frequency regulation of thermal power units. Firstly, a 250kW/50kWh FES unit model and a 250 kW/500kWh lithium-ion BES unit are established and their charging and discharging characteristics are analyzed. Next, a simulation model of a 250MW thermal power unit is established and validated. Then, the capacity configuration method of HESS is developed, which can double the comprehensive index of secondary frequency regulation (SFR) for thermal power units. In the next step, the coordinated control strategy for the thermal power unit and HESS based on state of charge (SOC) control of HESS is proposed to reduce life loss of thermal power units. Finally, the coordinated control strategy was validated through simulation experiments using actual output power data from a 250 MW thermal power unit and the constructed simulation model of the thermal power unit and HESS.