直流炉机组简化非线性模型及仿真应用

A Simplified Non-linear Model of a Once-through Boiler-turbine Unit and Its Application

通过合理简化和机制分析,建立适用于直流炉机组协调控制系统控制器设计的简化非线性数学模型。建模时考虑制粉环节、减温水环节和回热加热对过程输出的影响。该模型以燃料量指令、总给水流量、汽轮机阀门开度为输入,以汽轮机功率、主蒸汽压力和汽水分离器出口焓为输出。结合某1 000 MW超超临界机组运行数据辨识得到了在50%负荷到100%负荷范围内工作的机组模型参数。对模型进行了开环阶跃扰动实验和现场运行数据对比实验。仿真结果表明,模型开环动态特性与实际机组开环特性在本质上一致,且具有一定精度,可以用来设计协调控制系统控制器。

A simplified nonlinear model which was suitable for the controller design for coordinated control system of a oncethrough boilerturbine unit was developed with reasonable simplification and physical analysis. The direct blowing pulverizing system, the attemperations and the regeneration were taken into account in the modeling process. In this model, fuel command, total water flow and turbine governor valve position were considered as inputs and turbine power, main steam pressure and specific enthalpy at the steam-water separator outlet were considered as outputs. Parameters of the model for load variation between 1 000 MW and 500MW were identified with operation data of a 1 000 MW ultrasupercritical unit. Step forced simulation test and comparison tests with operation data were done to test the model. Simulation results show that this model has same dynamic characteristics with the actual unit and can predict output changes with certain accuracy which means that it is fit for the controller design of coordinated control system.