Modeling And Performance Improvement Of Primary Frequency Modulation System Of Thermal Power Unit Based On Particle Swarm Optimization Identification

With the development of national economy,the demand of electric power is increasing,and the operation and management level of electric power system is also being improved.As one of the important indexes of power grid security,power grid frequency,which is related to the safe and stable operation of power system,has been paid more and more attention.At present,thermal power units play an important role in the auxiliary services of power frequency regulation and peak load regulation,so it is of great significance to improve the primary frequency regulation capability of thermal power units.The implementation rules for auxiliary service management and grid operation management of regional grid connected power plants(hereinafter referred to as "the two rules")issued by the regulatory authorities of the National Energy Administration stipulate the responsibilities and obligations of thermal power units in the process of primary frequency regulation,and the relevant assessment requirements are increasingly strict.However,it is increasingly difficult to adjust the grid frequency.On the one hand,due to the continuous adjustment of the energy structure,the proportion of wind power,photovoltaic power generation and other new energy generation connected to the grid increases,and its own randomness,volatility and uncontrollability increase the disturbance on the power side.However,the installed proportion of thermal power units in the power system continued to decline,and the number of annual generation hours decreased in recent years.At present,the frequency modulation and other auxiliary power grid The service is mainly performed by traditional thermal power units,which presents a greater challenge to the frequency control and regulation ability of thermal power units.On the other hand,the transformation of energy saving and environmental protection of thermal power unit limits its primary frequency regulation ability to a certain extent,especially in the heating season,the grid related ability of the unit is limited by the way of thermal power setting.The operation of supercritical units not only improves the thermal economy of units,but also limits their ability to participate in the primary frequency modulation of power grid.These problems all put forward higher requirements for the control ability of primary frequency regulation of thermal power units.How to improve the primary frequency regulation ability of thermal power units is of great significance.In this paper,a 350 MW supercritical thermal power unit was taken as the research object.By analyzing the physical process transfer function,the simulation model of the steam turbine and its speed control system was established in the Simulink environment of MATLAB.The model of the steam turbine governor control system,the electro-hydraulic servo system and the prime mover were studied.Based on the processed data,particle swarm optimization algorithm was used to identify the key parameters in the simulation model,and the simulation results and the actual results were checked to improve the model.Finally,a simulation model for engineering simulation was obtained,which can be used to predict the relevant parameters of the unit more accurately and provide reference for the control optimization of the actual operation process.The optimization of the flow characteristic curve of the high-pressure regulating valve was carried out.The influence of the flow characteristic of the valve on the primary frequency modulation and the flow calculation method of the high-pressure regulating valve were analyzed.An algorithm-based valve flow characteristic tuning method was proposed.The optimization results show that this method can improve the linearity of the flow characteristic curve and make the primary frequency control process of the unit more accurate.This paper also uses the graphic user design module of MATLAB to build a software platform for performance analysis of primary frequency modulation.The simulation model was embedded in the platform,which can identify and calculate the performance parameters and assessment parameters of primary frequency modulation.This platform had built a general identification and analysis environment for steam turbine and its speed governing system,which would be convenient for operators to identify and analyze the units,fully tap the primary frequency regulation capacity of thermal power units,meet increasingly strict assessment standards,and improve the analysis capacity and work efficiency of the power generation end.