In order to improve thermal economy of the unit participating in peak shaving and determine the power generation cost of thermal systems under different operating conditions

a thermoeconomic model for combined optimization of main steam pressure and exhaust steam pressure of the thermal system is proposed. In this model

the internal and external three-layer iterative cycle logic is used in the algorithm design

the coupling relationship among the parameters of the thermodynamic system is analyzed from mechanism level

and all the steam-water parameters of the system and the calibration values of flow rate at all units after the parameter perturbation were obtained. The data are used to calculate the thermoeconomic indexes and optimize the system. The joint optimization solution of the main steam pressure and condenser vacuum at different loads and ambient temperatures was obtained. The results show that

the combined optimization solution of the main steam pressure and exhaust steam pressure is better than the single optimization solution of the main steam pressure. The generation cost of the thermal system decreases with the increase of unit load and increases with the ambient temperature. The thermal system is more economical in winter. It suggests that the influence of seasonal factors on the generation cost of the system should be taken into account when setting the generation price of thermal power units.