Research On Delay Analysis And Suppression Method Of Steam Turbine DEH System

As the increasing electric power demands,the capacity of thermal power units is also increasing.The use of single-unit large-capacity units also put a challenge to the unit's control system.As the speed response of the DEH system become more quickly and sensitive,the influence of delay time on the damping of the DEH system increase greatly.Therefore,the influence of the delay time of each link in the DEH system on the damping of the power system should be studied.The suppression method is of great significance to enhance the robustness of the system and maintain the stable operation of the power system.In this paper,the stability and safety of the integrated couple-networking system are researched,from the perspective of damping of the DEH system from different links.Firstly,according to the continuity equation and the energy conservation equation,this paper uses modular methods to model the steam turbine,controller and electro-hydraulic actuator,and combines the single-machine infinite grid model and the DEH system model together.Then,according to the power system toolbox,the two-machine five-point model is used for the couple-networking model for simulation.Secondly,according to the frequency domain analysis under the different delays of the single-machine infinity overall power system,it is found that the different delays of the speed feedback link,the electric power feedback link,the oil motive action link and the displacement sensor link have different effects on the damping of the integrated power system.Subsequently,a delay suppression method based on proportional differential feedforward control and overshoot feedforward control is proposed.The two methods are theoretically deduced on the single-machine infinite integrated power system and simulated on the single-machine infinity overall power system and the two-machine five-point simulation model.The results show that the two feedforward control methods have good effects on the delay of different links.Certain inhibitions demonstrate the effectiveness of the two methods for delay suppression.Finally,the effects of the two methods in the same link and the same delay time are compared,and the advantages and disadvantages of the two methods are analyzed and compared.The feasibility of the two methods is also proved.