基于预给煤动态模型的直接指令平衡系统在火电厂协调控制中的应用

配置直吹式制粉系统的大容量火电机组存在如下问题:制粉系统迟延长、锅炉热惯性大;在自动发电控制(AGC)调节中负荷响应迟缓,动态跟随性差;滑压运行时汽压调节偏差大,系统可控性差。基于预给煤动态模型的直接指令平衡系统,利用锅炉预给煤模型和汽轮机前馈模型对机组负荷控制的动态调节分量与偏差修正分量实施解耦,利用汽压设定值模型与滑压段附加锅炉指令模型对滑压段汽压的动态调节过程进行解耦,对负荷与汽压调节进行分时调度。利用机组对象特性的特征参数,根据指令模型结构进行工程整定,直接指令平衡系统在浙江省内得到应用,提高了机组负荷跟随性能与动态调节精度。

Application of Direct Instruction Balance ( DIB ) system based on the pre-feed coal dynamic model in CCS of thermal power plants

There are some problems in the large-capacity thermal power units with direct-blow coal pulverizing system, such as long delay of pulverizing system and great thermal inertia of boiler;slow response to load and poor load dynamic following in AGC mode;large deviation in steam pressure control in sliding-pressure operation. DIB system based on pre-feed coal dynamic model decouples the dynamic regulation component and deviation correction component of load control by introducing the pre-feed coal model of boiler and feedforward model of steam turbine, and uncouples the dynamic regulation components of sliding-pressure by utilizing the steam pressure set-point model and additional boiler instruction model of sliding-pressure operation, so that the time-sharing operation for load and steam pressure regulation are realized. With the characteristic parameters of object features, DIB system was set and applied in Zhejiang. The application shows that this system can improve the load following feature and dynamic regulating precision of power units.