Study On Steam Turbine System Modeling And Sliding Pressure Operation Optimization

China’s energy structure that is rich coal,lean oil,less gas,determined that coal-based pattern of thermal power generation will not change in the next period of time.At present,due to the small number of peaked power plants designed and constructed in China,there is a lack of power supply which can stabilize the random fluctuation of power.The shortcoming of the power grid peaking capacity is obvious,which causes the active large capacity units to participate in the peak operation of the power grid.In order to ensure the safe and economical operation of the steam turbine,it is very important to establish the variable operating condition calculation model of the steam turbine system to analyze the energy saving and optimization operation of the steam turbine system.In this paper,the energy saving operation optimization of the unit is taken as the research direction,and the operating characteristics of the steam turbine system and the characteristics of the variable operating condition operating of the flow passage part are analyzed.A 600 MW supercritical steam turbine system is used as the object of study,according to the material balance equation,energy balance equation and steam turbine system variable operating condition calculation theory,and basing on the modular and hierarchical modeling idea,variable operating condition calculation models of the flow passage part and the main equipment of the unit are established,and the models are validated,results show that the relative error of the main parameters of the model are less than 5%,which can satisfy the engineering requirements.Secondly,based on this model,studying the optimal sliding pressure operation mode,analysizing the influence of the main factors on the sliding pressure operation mode,determining the mathematical model and corresponding constraint condition.The optimization of the main steam pressure of the unit is carried out on the basis of the minimum heat rate in the feasible pressure interval.Optimal operation initial pressur of the unit of different typical loads under different back pressure and plant pumping capacity and the corresponding optimal sliding pressure curve the load as the independent variable and the optimal sliding operation curve with the post-pressure as the independent variable are obtained,which optimizes the operation of the unit in a certain extent.Last,according to the sliding pressure curve with the governing stage pressure as the independent variable,the adaptive control method to keep the unit in the optimal sliding state is analyzed,this method can ensure that the unit is always in the best state of sliding pressure operation,regardless of the deviation of thermodynamic parameters and the deviation of thermodynamic system.