火电机组间接建模策略研究

Indirect modeling strategy for thermal power units

本文以超临界600 MW火电机组为研究对象,对火电机组间接建模策略进行研究。采用子空间辨识方法分步求解分立的系统模型,首先建立中间点温度模型和机组负荷、主蒸汽压力模型,然后由中间点温度为输入变量建立主蒸汽温度模型,所得模型克服了直接建模时主蒸汽温度模型不准确的缺点,研究了锅炉主要调节量对机组动态特性的影响,最后将分立模型进行组合,得到机组的整体模型。所得模型能较好地反映机组在额定工况条件下的动态特性,模型拟合度较好,对超临界机组控制器的研究具有一定的价值。

A supercritical 600 MW thermal power unit was taken as an object to study the indirect modeling strategy for thermal power units. The sub-space identification method was adopted to solve the discrete system model step by step. Firstly, the intermediate point temperature model, the main steam pressure model and the load model was built up. Then, the main steam temperature model was established by using the intermediate point temperature as the input variable. The obtained model overcomes the disadvantage of inaccuracy of the main steam temperature model in direct modeling. The effect of main adjustment of the boiler on dynamic characteristics of the unit was studied. Finally, the separate models were integrated into the overall unit model.The obtained overall model can better reflect the dynamic characteristics of the unit under rated working conditions and has good fitting degree. The result has practical value for researches on controllers in supercritical units.