基于广义预测控制的除氧器水位快速控制方法仿真

Control algorithm simulation of de-aerator water level based on generalized predictive control

凝结水节流技术利用低压加热器系统蓄热辅助响应一次调频、变负荷的功率需求,提高汽轮机稳态高调门开度,降低节流损失,提高机组运行经济性。该项技术应用时,受常规PID(proportional, integral and differential)除氧器水位控制响应相对较慢的约束,凝结水节流动作幅度较小,辅助负荷响应作用难以充分发挥。针对该问题,通过深入分析广义预测控制算法,提出一种基于广义预测控制的除氧器水位快速控制方法,用于在凝结水节流响应过程中出现过高或过低水位时,快速恢复水位,保障凝结水节流系统运行安全。仿真试验表明,该方法能够快速平抑除氧器水位扰动,在确保凝结水节流系统安全运行的前提下提高凝结水节流动作幅度。该方法可作为凝结水节流技术应用时的一种除氧器水位快速控制方法。

Condensate throttling technology(CTT) can be applied to response to the power needs of primary frequency control or load change control by release or store of thermal storage in low pressure heater system.The operation economy of thermal power units can be improved by the enhancement of steady state turbine governor opening which leads to reduction of governor throttling loss. When CTT is implemented, the amplitude of throttling flow is small due to the restraint of the relative slow response of existing PID(proportional, integral and differential) controller for de-aerator water level(DWL) control, which inhibits the full play of CTT benefits. Aiming at this problem, through in-depth analysis of the generalized predictive control(GPC), a DWL fast control method based on GPC was proposed, which is used to restore the water level quickly when too high or too low de-aerator water level happens during condensate throttling responding,so as to ensure the operation safety of the condensate throttling system. Simulation results show that the DWL disturbances can be restrained fast, and a large throttling flow can be achieved on the premise of the safety operation of CTT by proposed method. The proposed method can be a choice for DWL fast control when CTT is applied.