Improved coordinated control strategy of coal-fired power units with coupled heat storage based on supercritical carbon dioxide cycle

Abstract

With the rapid development of intermittent renewable energy sources, operating a power generation system, like coal-fired power plants that can ensure supply stability, has become increasingly challenging. In this study, an additional supercritical CO2 (sCO2) cycle is incorporated into coal-fired power units to improve load regulation capability. First, a dynamic model of the coal-fired power unit with the additional sCO2 cycle is established. Two improved coordinated control systems are designed to improve the power ramp rate, i.e., a switching controller and a dual controller. Finally, a 330 MW coal-fired power plant was simulated. The results show that the proposed control method could effectively improve the load response characteristics. The integral of the absolute error (IAE) index and integral of the time square error (ITSE) index, of the coordinated control system based on dual control, were superior to those of the standard coordinated control system. The automatic generation control (AGC) performance indicators were found to be 9.03 and 8.76 in the load rise and decrease stages, respectively. Thus, the study provides a new direction for the application of sCO2 cycles in the field of coal-fired power generation.