A dual-layer control strategy during energy storage process for the thermal power plant integrated with thermal energy storage systems

The integration of thermal energy storages with thermal power plants presents a promising approach of improving frequency regulation ability. However, conventional coordinated control strategies are limited in addressing the expanded regulatory parameters introduced by thermal energy storage integration. Here, a dual-layer coordinated control strategy is proposed to achieve the frequency regulation of thermal power plants integrated with thermal energy storage, thereby enhancing operational flexibility and efficiency. The upper layer executes load command reconstruction based on the effective working ability of steam extraction, while the lower layer dynamically revises regulatory parameters through adaptive adjustments according to heat distribution variations. The feasibility of the proposed control strategy under various integration methods is evaluated using a 660 MW double-reheat power plant integrated molten salt thermal heat storage. Furthermore, comparative analyses of frequency regulation potential and efficiency are conducted. Frequency regulation potential is the strongest when the extraction steam point is located at the inlet of intermediate-pressure cylinder, achieving a peak load down rate of 8.5 % THA·min⁻¹. The standard coal consumption rate decreases with the extraction steam ratio, with a maximum decrease of 19.0 g·kWh⁻¹. Notably, the extraction steam ratio exerts a stronger effect on system efficiency than the extraction steam point. The proposed dual-layer control strategy enables the frequency regulation process in thermal power plants assisted by thermal energy storage, thereby enhancing the flexibility. This work provides supports for grid de-carbonization, and points to future research, including applying machine learning for predictive parameters and incorporating dynamic electricity prices to maximize operational benefits.