超临界机组控制特性和控制策略分析

Control characteristics and its strategy analysis of supercritical units

针对超临界机组强耦合、非线性的被控对象特性,对其主控参数的关系进行分析。运用热力学理论阐述了面向焓值控制给水量的理论基础和优势,指出直流锅炉的给水量控制就是建立机炉间良性的能量平衡关系。以扬州二电厂2×600MW超临界机组为研究对象,介绍了机组协调、给水-汽温控制策略及其要点,揭示了直流炉控制思想的核心:以关键变量(主汽压和焓值)为对象,通过前馈、变参数、动态修正等技术手段,注重煤-水-功率在大范围内的动态匹配和快速响应,保证机组随时处于一个可控的良性状态。

Aimed at the characteristics of controlled objects for supereritieal units such as strong coupling and nonlinearity, the relationship of main control parameters were analyzed. Based on the thermodynamics theory the theory elements and advantages of enthalpy-oriented feed water control were introduced, in addition, the feed water control of once-through boiler was pointed to mean establishing a good energy balance between turbine and boiler. With the 2x600 MW supercritical units of Yangzhou No.2 Power Plant as study objects, the control strategy and the key points of unit coordinated control and feed water-steam temperature control are fully discussed, and the core of one-through boiler control thought was presented as well, i.e. taking the key variables （main steam pressure and enthalpy） as object, and taking emphasis on the dynamic match and quick response of coal-water-power in a large range, several technical means such as feed-forward, parameter adjustment and dynamic modification were used to ensure units operating under good controllable conditions at any time.