Impact Study of Expander Automatic Control on Operational Stability During AA-CAES Startup Process

Aiming at the energy release process of the expander of the compressed air energy storage system, based on the energy release model of the expander, the temperature and pressure at the entrance are PID controlled. By comparing and adjusting the input parameters of the temperature gain coefficient and the pressure proportional coefficient of the expander, the influence of the output power, outlet temperature and outlet pressure during the start-up process of the expander, and the selection of appropriate parameters on the stability control of the start-up process, the aim is to solve the problem of the impact of sudden failure of key equipment on the stability of the unit. The results show that the peak value of expansion ratio at K = 6 is about 1.88 % higher than that at K = 2, while the peak value of isentropic efficiency at different K is consistent, reaching 0.88. In addition, When the inlet pressure coefficient Kp is set to 0.5, the output power peak is 0.8% higher than that at Kp = 0.9, and the pressure drop becomes more gradual, demonstrating improved response smoothness. The results show that the start-up performance of the expander can be significantly improved by reasonably regulating the PID parameters, which provides a control strategy basis for solving the problem of unit stability decline caused by key equipment failure.