Application Of DCS In A Large Coal-fired Power Plant

The boiler is a necessary power equipment of industry sectors such as generation of electrical energy, oil refinery, chemical industry, papermaking and refinement of sugar and so on. In order to ensure the production and security, the auto-control is very important. And the boiler water level is an important variable to be controlled. Because the boiler water lever is an important index of industry boiler safety and stabilization. It is important meaning to ensure water level in a finite range for increasing quality of steam and reducing wastage of equipment and insuring safety of whole system operation. At present, the most common method is PID control.This article has carried out detailed analysis to the boiler water level's dynamic characteristic and several used control methods, and determines the connection of traditional PID control with the boiler water level's three-variable control. According to summarizing and describing of skill worker's practice experience, it gained non-precise control rules.Designing models of boiler drum water-level control system mainly includes single-impulse, double-impulse and three-impulse, two former models of which have the features of simplicity and low cost, but can not control false-water-level; the last model of which has the features of complexity and high-cost compared with the two former models, but can control false-water-level and can reach good effective control. In this paper, the algorithm based on the model of three-impulse boiler's drum water-level control system and analyses the principle, theory and realization of the algorithms of PID control.This paper describes DCS system configuration scheme, including data acquisition, data communication, control programming, monitoring picture of PC, alarm and historical data inquiry.This paper designed a set of DCS control system which is satisfied with us look from actual operation of the control effect, this control method whose control high-speed, stability, adaptability, all have reach the device requirements.