火力发电厂单元机组给水全程控制系统浅析

Analysis on full-range feed-water control system of thermo-electric generating unit

给水全程控制系统是火力发电厂单元机组协调控制中的主要子系统之一,针对其可靠运行直接关系到整个发电系统的安全问题,采用单冲量和三冲量控制系统有机结合的控制策略,应用自动控制理论对单元机组给水的要求和特点进行了全面的分析,使单元机组给水全程控制从锅炉点火到机组满负荷运行,始终保持汽包水位在允许的范围内,而且系统稳态误差小,控制精度高,超调量小.此外还提出了在系统设计时应注意的几个关键问题,这对单元机组给水全程控制系统的设计和调试均具有一定的参考价值.

The full-range feed-water control system is a main subsystem of thermo-electric generating unit in coordinated control. Its reliability is most closely related to the safety of whole power network. The feed-water features and requirements of thermo-electric generating unit were analyzed comprehensively based on basic automatic control theories, and the control strategy was realized by combining three-impulse with single-impulse feed-water control system. From startup to full load operation, the full-range feed-water control always keeps the steam drum level within an acceptable range. The system has the characteristics of higher water-level control accuracy, smaller overshoot and lower error in steady state. In addition, several key design techniques are presented, which can be applied to the design and debugging of the full-range feed-water control system.