Research And Realization Of State Observer-Based Control System For Main Steam Temperature

The main steam temperature of the power plant directly affects the thermal efficiency of the whole plant and the safe operation of the equipment.Therefore,the main steam temperature control system is one of the most important control systems in the power plant.It is a widely used method to control the temperature of the main steam by using water cooling.The characteristic of the water desuperheater,which is far away from the superheater outlet,causes the main steam temperature controlled object to have large delay and large inertia.With the increase of installed capacity and the continuous increase of the superheater pipeline,the adjustment hysteresis is greatly increased,and the control difficulty is also increasing.Now the common main steam temperature control system is the PID cascade control system and the main steam temperature control system with pre-derivative differential signals.With the increasing difficulty of control,these two control schemes are increasingly difficult to meet the control requirements,which not only can not control the large delay object in time,but also produce large overshoot,making the control effect not ideal.Therefore,it is urgent to propose a new and more suitable control scheme.Taking into account the factors above,a main steam temperature control system based on the state observer is built,and its robustness and practicality is in-depth studied in this paper.Firstly,the state feedback based on observer with integrator control scheme is obtained through the stepwise study.Then the robustness of the control system is studied in detail by changing the parameters of the observer separately and implementing the control.The final simulation curve shows that the state feedback based on observer control system has good robustness and can adapt to the complicated situation in the field.At the same time,the state observer algorithm is added to the optimal control station which has high reliability,good real-time and strong stability and has been successfully applied in the field.And then the state observer is used as an advanced algorithm module in the optimal control station,and a main steam temperature control system based on the module is built.The main steam temperature control system based on the state observer has good characteristics and can meet the demand of the main steam temperature control in the power plant through the obtained response curve in optimal control system.