超超临界机组汽温控制策略研究及应用

Research and Application on the Steam Temperature Control Strategy of the Ultra Supercritical Unit

由于超超临界机组复杂的动态特性、变参数的运行方式、多变量的控制特点,采用传统的设计方法难以对超超临界机组主汽温进行有效的控制,因此开展了超超临界机组主汽温控制策略研究。通过对当前典型的超超临界主汽温控制策略进行分析,针对中电芜湖发电厂660 MW超超临界机组汽温被控对象的特性,设计了新型的过热汽温控制系统。该系统分别采用控制给水中间点焓值的方法实现过热汽温的粗调,并采用基于物理机理的减温水控制方案实现过热汽温的细调。在大负荷范围和高负荷变化速率的工况下,通过对控制系统的整定和优化,克服了过热汽温大延迟和大惯性的缺点,调节品质优良,提高了机组运行的经济性。为今后同类型系统设计、调试提供了借鉴。

Owing to the complicated dynamic characteristics, variable operation mode and multi-variable control characteristics of supercritical units, the traditional design method of supercritical unit failed to control the main steam temperature effectively. Therefore, the main steam temperature control strategy of the ultra supercritical unit is studied in this paper. The main steam temperature is controlled by analysis of the typical main steam temperature control strategy of the uhra-supercritical unit. Aiming at the charac- teristics of the controlled object in project of Wuhu Power Plant, the 660 MW ultra supercritical power u- nit, a new type of superheated steam temperature control system has been designed. In this system, coarse regulation of the temperature is carried out by controlling the intermediate point enthalpy of the feed-water, and the fine regulation of the temperature is implemented by the physical mechanism control. Under large load range and high load changing rate, through tuning and optimizing the control system, the large time lag and large inertia of the process are overcome, and excellent regulation quality is ob- tained. It is worth to be used for reference in designing and debugging of similar systems.