Model Identification And Control Of Reheat Steam Temperature Of USC Double Reheat Unit

According to the actual operating results of the domestic USC(ultra-supercritical)double reheat units,the USC double reheat unit has better economic and environmental benefits than one reheat unit with the same capacity.Therefore,it will be a trend of high parameter and large capacity thermal power unit to develop USC double reheat unit before the 700? high-temperature materials are successfully developed.Due to the complexity and particularity of double reheat unit's boiler construction,it becomes more difficult to control the reheat steam temperature.Relying on the 1000MW USC double reheat unit of Huaneng Laiwu Power Plant,the following study of the control strategy of its reheat steam temperature system has been done in this paper:(1)On the emulation platform of 1000MW USC double reheat unit which was developed by Xi'an Thermal Power Research Institute adopting APROS emulation software,the open loop dynamic characteristic tests for its reheat steam temperature system are conducted respectively in 100%?75%load point.According to the input and output data,the transfer function model of the reheat steam temperature system in 100%?75%load point are obtained using the Differential Evolution algorithm with the global search strategy.(2)On the basis of studying and analyzing the transfer function model of the above reheat steam temperature system,PID control strategy and decoupling predictive control strategy with input constraints for the reheat steam temperature are designed.On MATLAB/SIMULINK simulation platform,the setpoint tracking experiment and robustness experiment aiming at these two control strategies are done,moreover,its control effects are analyzed and compared.(3)To measure the control quality of the designed reheat steam temperature control strategies in designed unit,the increasing and decreasing load test are done on the emulation platform of 1000MW USC double reheat unit,and the control effects of these two reheat steam temperature control strategies are analyzed and compared.The results show that the decoupling predictive control strategy with input constraints could achieve better performance than PID,but not as good as PID in disturbance rejection.