Many blackout accidents indicate that the medium-and long-term stability is much important for modem large-scale interconnected power grids.The proportion of supercritical (ultra supercritical) units to thermal power units grows very fast and its mathematic model is significant to the medium-and long-term stability analysis.In this paper,the physical equations presenting the dynamic characteristics of supercritical (ultra supercritical) units are derived and a simplified non-linear transfer function model is built.In addition,the model is identified and verified by the testing data of one 1 000-MW ultra supercritical unit.The results show that there are only 12 parameters in the model and the parameters can be easily obtained from the parameter identification procedures.The model and its identified parameters are accurate enough compared with the test data,which aresuitable for the medium-and long-term stability analysis of power grids.%大停电事故表明,电网中长期稳定性对现代互联电网更为重要.超(超)临界机组在中国火电装机容量中的占比飞速增长,建立适用于电网中长期稳定性分析的超(超)临界机组数学模型具有重要的意义.推导了描述超(超)临界机组动态特性的物理方程,建立了简化的非线性传递函数数学模型,并采用某1000MW超超临界机组的实测数据对该模型进行了参数辨识和模型验证.结果表明:所建立模型仅有12个模型参数,可方便地通过实测数据的参数辨识获得,所建立的1000MW超超临界机组数学模型及其辨识得到的参数与实测结果相比具有较高的精度,适合于大规模电网的中长期稳定性分析.
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