超临界直流锅炉长期动态特性的建模与仿真

Modeling and Simulation of the Long-term Dynamic Characteristics of a Supercritical Once-through Boiler

超临界直流锅炉长期动态特性对超临界直流锅炉汽轮机发电机组的仿真和控制系统设计具有十分重要的意义。为了快捷、全面、可靠地研究调峰及负荷变化过程中超临界直流锅炉的长期动态特性 ,通过合理地机理分析和模型简化 ,应用状态空间方法建立了超临界直流锅炉省煤器、水冷壁、过热器及再热器的简化数学模型 ,推导出工质侧压力流量变化的一组更为简洁、新颖的非线性关系式。最后以上述简化状态空间模型和非线性关系式为工具对某 6 0 0MW超临界直流锅炉的长期动态特性进行了仿真研究 ,仿真结果正确。本文的研究为超临界直流锅炉的长期动态特性研究提供了一个十分简便的数学模型和方法。

The long-term dynamic characteristics of a supercritical once-through boiler play a key role in the simulation and design of the control system of a supercritical once-through boiler and turbogenerator unit. To conduct a rapid, comprehensive and reliable study of the long-term dynamic characteristics of a supercritical once-through boiler in the process of peak-shaving and load changes, a simplified mathematical model has been set up for the economizer, water wall, superheater and reheater of a supercritical once-through boiler. The model building has been carried out on the basis of a rational mechanism analysis and model simplification and through the use of a state-space method. A group of fairly concise and innovative nonlinear relations for the pressure and flow rate changes at the working medium side have been derived. Finally, with the help of the above-mentioned simplified state-space model and nonlinear relations a simulation study was conducted of the long-term dynamic characteristics of a 600 MW supercritical once-through boiler. The simulation results were found to be accurate. The present study has provided a very simplified and convenient mathematical model and method for the research of long-term dynamic characteristics of a supercritical once-through boiler.