Research On Frequency Response Characteristics And Load Frequency Control Of High Proportion Wind Power System

With the increase of the scale and proportion of wind power connected to the power system,the functional requirements and control quality requirements of its participation in frequency regulation are increasing day by day,which requires an accurate description of the frequency response characteristics of the power system with wind power,and an accurate model of the frequency response of wind turbine generator needs to be established.In addition,the fluctuation and uncertainty of wind power output also pose a greater challenge to load frequency control.Appropriate control strategies are needed to improve the control quality.This thesis mainly studies the description of frequency response characteristics of wind turbine at the primary frequency regulation level and establishes its frequency response model.On this basis,the load frequency control model of two area power system with high proportion wind power is established,and the uncertain load frequency control at the secondary frequency regulation level is carried out.Firstly,the mathematical model of doubly fed induction generator wind turbine is established,and the method of wind power participating in frequency regulation is mainly discussed.On this basis,at the level of primary frequency regulation,based on the single area system frequency response model,the whole process of wind power participating in frequency regulation is simplified to a single working condition description.Through the description of equivalent inertia and damping coefficient,a simplified model of system frequency response with wind power is established,which explains the improvement effect of wind power participating in frequency regulation on the frequency response characteristics of the system.The problems in the existing model is analyzed and discussed.Secondly,since the existing single working condition wind turbine frequency response model ignores the relationship between frequency control mode and its operation state,it is not suitable for the description of system frequency response characteristics under all wind conditions.In this paper,the wind speed is divided according to the frequency regulation characteristics of the wind turbine,and based on the frequency regulation control method of the all wind conditions of the wind turbine,the relationship between the integrated inertial control additional active power,wind speed fluctuation and the output of the wind turbine is deduced and described by using the small signal increment method,and the frequency response model of the whole wind condition of the wind turbine is established.The correctness and effectiveness of the all wind conditions model are verified by simulation comparison.Finally,aiming at the impact of uncertainty of the fluctuation of wind power output on load frequency control,based on the wind turbine whole wind condition frequency response model,a load frequency control model of two area power system with high proportion wind power is established.On this basis,a load frequency uncertainty artificial intelligence control method with wind power based on variable universe cloud PI is proposed at the level of secondary frequency regulation.Considering the problem of fixed universe in traditional cloud controller,the idea of variable universe is introduced into cloud model controller to make the universe of cloud controller realize dynamic adaptive adjustment.In order to avoid increasing the complexity of the controller,the domain scaling factor is designed based on the function form.The simulation results show that the variable universe cloud PI load frequency controller has better control effect and can effectively deal with the uncertainty problem under the superposition of wind power fluctuation and random load disturbance.