凝结水节流的动态特性分析及模型辨识

Research on dynamic characteristics analysis and identification based on condensate throttling

为了满足新能源电网的需求,火电机组的变负荷能力必须提高。而凝结水节流可以通过利用机组蓄能,快速、有效地激发机组的变负荷能力,满足电网的需要。以某电厂350 MW超临界火电机组为例,分别在95%工况、85%工况和75%工况进行除氧器上水门节流和凝泵变频节流试验,对节流过程中相关参数变量进行分析,研究不同负荷下机组的动态特性;结合粒子群智能算法完成不同工况、不同节流方式的模型辨识,比较两种控制方式的控制效果。结果表明:凝结水节流量越大,机组提升负荷的能力越强;不同条件下采用粒子群智能算法辨识得到的模型与机组实际的动态特性曲线高度吻合,除氧器上水门节流快速提升机组负荷的能力要优于凝泵变频节流,为大机组控制优化提供参考。

In order to meet the needs of the new energy grid, the load capacity of the thermal power unit must be increased. Condensate throttling can quickly and effectively stimulate the unit's variable load capacity by using the unit's energy storage to meet the needs of the power grid. A 350 MW supercritical thermal power unit of a power plant in Hainan is taken as an example. The deaerator upper throttle throttling and condensate pump frequency conversion throttling test were carried out in different working conditions(95%/85%/75%) respectively. The related parameter variables were analyzed to study the dynamic characteristics of the unit under different loads. The particle swarm optimization was used to complete the model identification of different working conditions and different throttling modes, and the control effects of the two control modes are compared. The results show that the more the condensate water saves, the stronger the unit's ability will be to lift the load;the model identified by the particle swarm optimization under different conditions is highly compatible with the actual dynamic characteristic curve of the unit, and the deaerator upper throttle throttling fast lifting unit. The capacity of the load is better than that of the condenser pump, which provides a reference for the subsequent control optimization.