Research Of Thermal Stress Control Of The Startup Process For The Steam Turbines

In this paper, recurrence formula was proposed for the analytic method of the temperature and thermal stress calculation of steam turbine rotor under the condition of the third of boundary. The author drawn up software and make a simulation experiment in the startup of the units of Chao Yang plant. A set of scheme was drawn up for thermal control system of the homemade 200MW steam turbine, so the paper provided theoretical grounds for the optimization of the startup process and operation mode of the 200MW units of Chao Yang plant. In the paper, a method of forecasting and controlling control for thermal stress was provided for the large delay of boiler and steam turbine. It is realized to make the thermal stress actually vibrate in the zone of the equal thermal stress during the startup of the steam turbine.. The mathematical models were built for control system of the homemade 200MW unit .At the same time, the paper improved the controller of the DEH control system. The traditional PID control system based on exact mathematical models could not meet the demand because the difficulties of steam turbine control are many uncertain disturbing factors which affect the output parameters (speed ,power).And because the great difference of the delay of the process change was caused by disturbing factors, the designed control system could not meet satisfied purposes under all working conditions. One of the solving methods is change the control strategy. The author adopted advanced control which integrates the self-turning factor fuzzy control and traditional P1 control to build the controller .The system constructed by the controller has fast response, small overresponding rate and strong resisting disturbance etc.