Dynamic Modeling And Turbine Backpressure Control Simulation For Heavy Duty Gas Turbines

As a crucial link in the field of electric power production,heavy-duty gas turbines have the advantages of high efficiency,fast startup,and low pollution.With the proposal of the dual carbon plan and the increase in proven natural gas reserves in China,the independent research and development of heavy-duty gas turbines has received increasing attention.In order to reduce the cost of the research and development process and subsequent maintenance process while solving the load absorption problem of renewable energy,the dynamic model modeling and simulation analysis of gas turbines based on the large computing computer simulation platform has become the core research content of independent research and development of heavy-duty gas turbines.This paper takes a single shaft heavy-duty gas turbine as the research object to conduct dynamic modeling and simulation research under full operating conditions of the unit.After a detailed investigation of the research results on dynamic modeling of heavy duty gas turbines at home and abroad,the current mainstream methods are used to conduct unit main body modeling,study various unit regulation strategies,and simulate and analyze various disturbance processes.The main contents are as follows:(1)Based on the modular modeling method,the heavy-duty gas turbine is divided into several main components according to typical nodes,including:compressor,combustion chamber,turbine,gas physical property calculation module,inertia module,and control strategy module.Different methods are used to model the main components mentioned above.The compressor and turbine are modeled using a stepwise superposition method combined with characteristic curves,and the effects of IGV and cooling air on the performance of the compressor and turbine are fully considered;Combustion chamber modeling based on the law of conservation of energy;Establish a gas physical property calculation module through secondary modeling;The control strategy module is modeled based on the PI control principle.The static and dynamic validation of the model were conducted to prove that the model has good simulation accuracy and meets the requirements of dynamic simulation.(2)Unlike the previous dynamic simulation of heavy duty gas turbines,which mainly focused on the dynamic characteristics of the entire unit or compressor,this paper conducted research on the dynamic characteristics of gas turbines under load fluctuation and ambient temperature fluctuation disturbances.The simulation results fully comply with the working mechanism of gas turbine,revealing the changing rules of dynamic response curve of gas turbine under load fluctuation and ambient temperature fluctuation disturbances.(3)The dynamic characteristics of gas turbine units with varying turbine back pressure are studied.By comparing and analyzing the simulation results of different input signals,the effects of different amplitude and rate of turbine back pressure changes on the dynamic characteristics of gas turbines are explored.The differences in response characteristics of various parameters of gas turbines using n&T3 and n&T4 control strategies are analyzed when the back pressure gradually decreases.(4)The dynamic response curves of back pressure control units under different disturbances are studied.By comparing and analyzing the dynamic characteristics of the unit with traditional control strategies,the optimization effect of turbine back pressure control on the dynamic response characteristics and unit control range of the gas turbine is verified,including that the gas turbine has faster response speed and higher stage efficiency at low back pressure;As well as load rise disturbances and ambient temperature rise disturbances,the back pressure control unit has better turbine inlet and outlet temperature control capabilities.