Modeling And Accuracy Research Of Main Steam Temperature For 1000mw Ultra-supercritical Unit

Main steam temperature is an important parameter for ultra-supercritical units, in order to improve the control level, a suitable model is a must. This system has such characteristics as multi-variable, strong coupling, large inertia, large delay, and disturbance experiment is always not allowed, causing the traditional modeling methods can’t meet the requirements. Since the use of DCS and SIS, a large number of field data can be easily stored and viewed, which contains a wealth of information that can be excavated. At the same time, simulation technology has been able to simulate Field operating characteristics, providing conditions for the modeling of main steam temperature system.About the main steam temperature system multivariate modeling, the main tasks are as follows:First, we improved PSO and got mixed PSO base on natural selection, and tested.Second, we analyzed the field data with principal component analysis and extracted five major factors affecting the main steam temperature. They are secondary temperature reduction flow, fuel, water, the main steam flow and flue gas oxygen content, as the input variables of main steam temperature system model.Third, we used simulation systems for step disturbance and got five step response models as standard models; Operational data was acquired under closed loop conditions of load lifting process. Identify the parameters of five channels at the same time and got the multivariable models. Through comparison with the standard model, proved the multivariable systems can meet the accuracy.Last, on the basis of the simulation model, conducted further correction for the five transfers with the data selected from a large number of field data, and got real for on-site steam temperature multivariable systems model, and validated.The method proposed in this paper combined the mechanism, experimental and intelligent modeling very well and solved the problem that large-scale or frequent experiments at production site is not allowed or that there are no conditions for step disturbance, overcoming the difficulty of selecting the initial value range and model structure.And established multivariate models which are useful for the study of main steam temperature controlling strategy.