Model Identification And Control Of Superheated Steam Temperature For Ultra-supercritical Double-reheat Unit

Double-reheat steam system is a key process to increase the rated parameters and improve the thermal performance of the ultra-supercritical power units.In China,the construction of ultra-supercritical double-reheat power units is still in the initial stage,so relevant operating experience is scarce.Thus it's necessary to get to know the boiler's thermal performance,with the purpose of realizing more precise control of important parameters such as the temperature of superheated steam and reheat steam.As superheated steam is still the main part to transfer heat in double reheat steam system,and it can be affected by those measures intended to control reheat steam,so dynamic performance of superheated steam in double-reheat steam system has been explored in this article,and then the design of a new control scheme with better immunity performance is finished.Based on the simulation system of Laiwu Power Plant developed by Xi'an Thermal Power Research Institute,disturbance tests about spray water of the super heater and recycled gas have been made.The improved particle swarm optimization algorithm is used to identify the parameters of the model for superheated steam temperature.Based on this model,LADRC-Smith(linear active disturbance rejection control controller,LADRC)is designed to regulate desuperheating water,completing the superheated steam temperature control.In the end,LADRC-Smith controller is applied to the simulation system of real unit comparing with cascade PID control,with OPC protocol interchanging data between Matlab and Apros.The results indicate that improved particle swarm algorithm has high precision and the model can be used to carry out related researches of optimal operation and optimization control.Meanwhile,LADRC has better control effect than conventional cascade PID control strategy,and combined with Smith control,its strong robustness and adaptability can better cope with variation and disturbance of model,achieving even better control quality.Carrying out disturbance tests and control method test based on the simulation system of Laiwu Power Plant,and exploring the characteristics of superheated steam temperature and corresponding control method,can be of great value to current practical engineering.