锅炉蓄热系数是火电机组负荷-压力被控对象中一个关键动态参数,准确估计出其大小能够为优化协调控制系统提供重要支持. 依据对象负荷一压力简化非线性动态模型构建炉跟机方式的协调控制系统,从时域及频域角度分析其闭环响应特性,发现汽轮机蒯节门输入与燃料量输入对机前压力和发电负荷输出响应的时问及频率存在较大差异,可认为在小时间尺度范围内机前压力和发电负荷仅受汽轮机调节门输入的影响. 因此可利用短周期的一次调频扰动工况下的数据辨识锅炉蓄热系数,准确度与汽轮机调节门开度扰动试验相当. 通过某330 MW机组数据辨识及现场调试,证明以上方案可行.
The heat storage coefficient of the boiler is a key dynamic parameter of the load-pressure controlled object for thermal power units,of which the precise estimation provides important support for optimizing the coordinated control system.According to the simplified nonlinear dynamic model of the load-pressure object,the coordinated control system in the boiler following mode is established to analyze its closed-loop response characteristics using the frequency domain and the time domain methods.The results show that there are big differences in the time and frequency responses of the throttle pressure and the generation load outputs to the governor valve opening and the fuel flow inputs.It can be considered that the throttle pressure and the generation load are only affected by the governor valve opening within a small time scale.Therefore,the data under primary frequency regulation disturbance conditions in a short cycle are used to identify the boiler heat storage coefficient,which accuracy is good as that of the governor valve opening disturbance experiment.In addition,the feasibility of the methods is proved through the data identification and the field experiments in a 330 MW unit.