2*660 MW火电机组变频调速循环水泵建模与优化控制研究

Research on Operation Optimization for Circulating Water System with Frequency Converter of 2*660 MW Unit

对火电机组循环水泵进行变频改造,可实现循环水量的连续调节。精细化调整循环水泵运行组合方式及变频器频率,进而将机组调整到最佳真空运行,是冷端系统节能降耗的关键问题。以某电厂2*660 MW机组循环水系统为研究对象,建立了凝汽器、汽轮机低压缸与循环水泵耦合的冷端优化数学模型,研究了变频泵变速比对循环水系统功率与流量的影响,给出了不同运行模式的等效益分界线及变频泵目标频率的确定方法,基于EDPF-NT型DCS完成了循环水系统的闭环实时优化控制应用,进一步降低循环水泵的厂用电率,对同类型机组技术改造具有借鉴意义。

Frequency conversion modification of circulating water pumps of thermal power units can realize continuous adjustment of circulating water volume.The key issue of energy saving and consumption reduction in power plant are fine adjustment of circulating pump operation combination mode and determination of converter frequency,which can adjust the unit in the best vacuum operation.Taking the circulating water system of a coal-fired power plant with 2*660 MW unit as the research object,the cold-end optimization mathematical model coupling the condenser,turbine low-pressure cylinder and circulating water pump is established.The closed-loop real-time optimization control application of the circulating water system is completed through EDPF-NT DCS,which reduces the power consumption rate of circulating water pump,and is of reference significance for technical renovation of similar unit.