Simulation Modeling And Characteristic Research Of Distributed Energy System

Natural gas distributed energy system (NGDES) are developing prosperously in China. NGDES has been widely used in domestic industrial park and the city buildings because it is efficient and environmentally friendly. It has important practical significance to establish a high precision and real-time NGDES simulation model, which can not only evaluate the economy and security of NGDES, but also guide the operation optimization and control optimization of NGDES. Therefore, common equipment of NGDES is taken as the main research object. The static and dynamic modeling and simulation of NGDES are studied based on the Matlab/Simulink simulation platform.(1) Improvement of gas turbine modeling algorithmA compressor performance hybrid modeling method is put forward based on the similarity principle, compressor general characteristic equation is used to determine the model structure, and the data sample is used to determine the model parameters. On these grounds, LM2500+G4 Gas Turbine compressor model is established. The corresponding rule of heat transfer equation and heat balance equation are deduced based on the structural feature of LM2500+G4 Gas Turbine. On these grounds, estimation model of air cooling coefficient is established. The simulation result shows that simulation precision of LM2500+G4 Gas Turbine simulation model is improved by the compressor corrected characteristic curve and the estimation model of air cooling coefficient.(2) Improvement of waste heat boiler modeling algorithmHeat transfer coefficient of flue-gas side off-design model is deduced based on the principle of heat transfer. On this basis, the heat transfer equations of dual pressure waste heat boiler is improved, considering the influence of heat transfer efficiency of heat balance. The iterative calculation of heat transfer equations is improved based on the principle of both accuracy and efficiency. Base on the principle of keeping the simulation precision, increasing the speed of the simulation, evaporator dynamic mathematical model is optimized to solve the algebraic loop problem in the simulation process. The simulation result shows that the static and dynamic simulation model of double-pressure horizontal unfired waste heat boiler has high precision, and can achieve real-time simulation.(3) Design of NGDES integration simulation platformHigh precision and real-time NGDES static and dynamic Simulink model are established by the connection of static and dynamic Simulink model of LM2500+G4 Gas Turbine, double-pressure horizontal unfired waste heat boiler, extraction condensing steam turbine and double-effect libr absorption chiller. And on this basis, NGDES integration simulation platform is designed combined with Matlab/GUI, which contains system configuration, parameter configuration, and human-computer interaction interface. The simulation result shows that NGDES Simulink model has high simulation accuracy, and can achieve real-time simulation. NGDES integration simulation platform can integrate the parameter setting, simulation results output, real-time data analysis and data storage.(4) Operating characteristics of NGDESThe influence rules of atmospheric temperature, atmospheric pressure and calorific value of fuel to the operating characteristic of NGDES are analyzed based on the NGDES static Simulink model. The simulation results show that, atmospheric temperature, atmospheric pressure and calorific value of fuel has important influence on the output power and efficiency of NGDES. The output power of NGDES is greatly reduced in the case of high temperature season, high altitude, low quality fuel. NGDES should be controlled in low temperature, low altitude and high quality fuel to achieve the greater output power and efficiency.