The Control System Research In Air-cooled Island Of The Direct Air-cooling Unit

With the development of power industry and environmental requirements, direct air-cooling technology in thermal power plants to be more widely used. Research and development of direct air-cooling system to effectively relieve water contradiction, control to eliminate the pollution is of great significance. This paper introduces the principle of direct air-cooling system, and the comparison of the indirect and direct air cold air cooling of the technical characteristics, and describes the island of air cooling system working principle and structure. Taking the600MW subcritical direct air-cooling unit as an example, summarizes the air cold island system control plan, including vacuum system control and back pressure control, steps control, antifreeze protection control, cleaning system control and fan control for overclocking. This article analyses the principle of back pressure control and back pressure for the unit operation of economic influence, summarizes the back pressure value of the choice method. In view of the current air cold island control in the system of back pressure value selection problem, and at the condition of the actual production, this text proposes options for automatically setting back pressure. This paper analyses the environment temperature and load to the influence of back pressure, does not affect the normal production in the case, use of field data get under different load history environment temperature and back pressure relationship. Because of the relationship between the approximate linear, by using particle swarm optimization algorithm is intelligent curve fitting. By choosing proper function relation between the types and accord with certain condition data, fitting out different environmental temperature and load the function equation back pressure relationship. Combining with the test curve and the operation experience, got a different environmental temperature, different operation conditions of air cooling unit economy back pressure value. Through the field DCS control module, realize back pressure adjusting loop of the automatic a given value. For air cold island automatic control system design and optimization have certain reference significance.