Improving flexibility of thermal power plant through control strategy optimization based on orderly utilization of energy storage

Operational flexibility in thermal power plants has assumed a growing significance in maintaining power grid stability primarily driven by the increased penetration of intermittent renewable energy sources. Substantial energy resides within the regenerative and boiler subsystems of thermal power plants, and optimizing the utilization of the stored energy is crucial for enhancing the operational flexibility of these plants. A novel coordinated control strategy, informed by the characteristics of distributed energy storage and power ramping stages of thermal power plants, is proposed. This control strategy systematically activates energy reserves within the deaerator, regenerative heaters, and boiler subsystems through load decomposition, valve regulation, and revised coal feeding rate, respectively. Control performance is subsequently assessed within a reference scenario. The results demonstrate a notable improvement in the control performance. The variations in the reheat steam temperature, main steam pressure, and output power are reduced by 2.0 °C, 0.47 MPa, and 2.4 MW, respectively. Moreover, the maximum power ramp rate increases from 1.5 % to 5.5 % Pe₀ min⁻¹. Furthermore, a substantial reduction in coal consumption of up to 7.09 % is achieved through the orderly utilization of energy storage. This study provides a comprehensive reference for enhancing the operational flexibility of power plants.