Abstract
This paper introduces the XDPS-400 control system which is used in Changxin power plant. . The system has the function of centralized monitoring control , AGC and frequency regulation. Also it hasreached the automation level for generating units above 300 MW.
With the practical project as example, the software system, hardware system and the function of XDPS-400 are introduced. The important of DCS in the comprehensive control system of power unit is presented. A new de-ashing method, known as the fly-ash air-transport technology with concentrated phase positive pressure, is introduced in this paper. Operating practices indicate that, this system are saving energy, lower maintenance cost, to improve environment and better comprehensive utilization etc., and can satisfy the requirements of coal-fired boilers for safety and economy operation in fossil power plant . In combination with the design of the ash handling system for the #4、#5 in Huaneng Power Plant, the principle, work flow, design parameters and structure of the pressurized seal pneumatic ash handling system are described with its features analyzed, which can provide reference for selecting pneumatic ash handling system in thermal power plants.
Besides, the ash handling system existence in view of my factory 2 ×135 MW units the question, from the ash handling with to be mad that the system, the ash handling system tube disposition and the control policy to loses shade which the ash system produces to make a sound and so on aspects to carry on the analysis.In the May of 2007,the #4、#5 stove the ash handling system to cancel the original PLC control, changed the DCS control (New China XDPS 6.0). In desulphurization construction period, New China Corporation to the ash handling PLC to enter the trapezoidal chart good translation and the configuration, and simulation run period of time, have not discovered the important flaw. However throws the time in the reality, is unusual the material number of times to rise suddenly, from January to April (PLC control) 9/months, (the DCS control) achieve 33 time/month of many to May to June.
So discovers the original system existence the insufficiency, and proposed the improvement program. Proved after the movement practice that the transformation is successful.
Keywords： 125 MW unit ; positive pressure; concentrated phase; air-transport
