A coordinated control strategy and dynamic characteristics of coal-fired units coupled with the S-CO2 energy storage cycle

Abstract

To ensure the safety of supply in the power grid, it is necessary to establish a power generation system with flexible regulation. This study proposes an innovative system coupling coal-fired units with a S-CO₂ energy storage cycle to improve the overall load regulation capability. First, a dynamic mathematical model of the coupled coal-fired power units and S-CO₂ energy storage cycle is established. The relative error associated with the model is found to be less than 5%. Then, the two operating conditions of the load up process and the load down process are combined, and the dynamic characteristics of the S-CO₂ energy storage cycle are studied and reported. The results highlighted that heating the boiler and supplying air can reduce the coal consumption rate by 2.29 g/(kW·h). Finally, a new coordinated control strategy based on mode switching and dual control is designed and implemented. The experiment conducted showed that the coordinated control strategy based on the dual control yielded the best performance, with the fastest response speed to the load command. Additionally, this control approach has the smallest integration value of the absolute error index and time squared error. Overall, the findings of this study provide useful information and serve as a reference for improving the flexibility of coal-fired power generation units.