A Study On The Control System Of Steam Temperature And Its Application In The Large Thermal Power Plant

Most of domestic 300 MW and more larger thermal powers adopt DCS control system at present, which improves automatic level of plant powers, and makes it possible that many new advanced control strategies could apply in control fields. It theoretically proves that advanced control strategies obviously superior to conventional control strategy in control character.DCS has been becoming conventional industry product from high-tech one, so there is severe competition in DCS price. In order to decrease cost of the products, most manufactories are reluctance to spend a plenty of energy dealing with application of exploitation research, most control strategy of DCS is conventional and classic. While PID controller doesn't demand exact math model itself, and PID control parameters, which exists definite physics relation, are easy to be adjusted on-line. Based on the two aspect reasons of objective and subjective influences results in limitation of application of advanced control strategy in widely, so dominant controller is just the same PID controller.This thesis utilizes DCS control system platform in being running, develops research of advanced control strategy and engineering practical application, and resolves the problem which steam temperature in power plant is difficult to be controlled. Aiming at the disadvantage quality of both super-heat steam temperature and re-heat steam temperature which used to easily make the units go beyond the limitation of steam temperature operation in Jiaxing Power Generation Co. Ltd., author uses new control idea--- vector-space control, and redesign the steam-temperature control system which has been obviously correcting fault and shortage of original strategy of steam-temperature control system. This thesis also analyzes main functions of sub-modules ,which include module of steam-temperature prediction, second stage attemperator in-let temperature dynamic control, assignment and transfer of first and second stage attemperator regulation task and etc. In the new steam-temperature control system in detail, and discusses how to improve the efficiency of power plants in the application of this new steam-temperature control system-- automatic adjustment of main steam-temperature control value from 540℃ to 542℃. The new steam-temperature control system based on vector-space, which has been performed for several years in a certain 300MW power plant, is better than the classic control system.