Circulating Fluidized Bed Units Distributed Control System Design And Implementation

Within the scope of normal movement, the thermal power plant should be able to quickly satisfy the demand of the changes of the external burden and participate in the modulation of the charged barbed wire net frequency. The unit of 50MW and under is comparatively low in automation, which can not satisfy the demand of current electricity net and guarantee the safety and economic circulation of the units as well. With the rapid development of computer technology, the automatic control system of the generating set has gradually developed toward the distributed control system (DCS).The demand for central management and dispersed control has pushed the development of DCS. The core is to supervise, to operate, to manage and to disperse control the production process with the help of the computer. DCS is a large comprehensive control system that can be layered in vertically and scattered horizontally. Based on the multileveled network, it can connect all kinds of control system and data processing equipment within the plant. As a result, it is possible to realize the share of information and the coordination of different parts and to fulfill a variety of control, management and decision making.The text argues how to design and realize DCS of the circulating fludized bed (CFB) boiler power plant in Zaozhuang Nanjiao thermal power plant. Based on his own working experience, the author argues in detail the design of the system and the realization of its function from the following aspects: the adoption of double-leveled redundancy network mode in consideration of the system's overall characteristics and its reliability; its systematic structure; controlling project and strategy; data management and design; techniques on network exchange.It also analyses in depth the control strategy of the machine set and methods to fulfill it. CFB power plant has too many measuring points and thus has difficulty in controlling in Zaozhuang Nanjiao thermal power plant. Challenged by the fact, we have devised a set of DCS, which has a variety of almost 3,000 measuring points. The fore part of the input/output (I/O)of the system makes use of control area network (CAN) intelligence module. The control station adopts 1:1 redundant heat backup project; specific stations for the operation personnel and maintain working stations for engineers and stations to store historic data are all established. The network structure runs with lOOMbps Ethernet and CAN network. On the top is the station for engineers and operation personnel. In the middle is the dispersed redundancy spot controlling station distributed process unit(DPU). It is in between the central net and on-the-spot total line net. At the bottom is the distributed intelligence I/O module.Practice proved that DCS has powerful function, advanced structure, stable characteristics and high ratio in performance and price. Once it is put into operation, it will contribute to the improvement of the safety, stability and economy of the operation of the plant.