| Among many new energy sources,wind energy is favored for its huge reserves and low development cost.Large-scale grid integration of wind power has become a global phenomenon.As the linking of wind power to the grid is done by a large number of power electronic devices,this behavior will reduce the inertia of power grid.If severe power disturbances occur,they can further increase the threat to the frequency reliability of the grid.Therefore,it is particularly necessary to study and analyze the frequency after system disturbance.In order to solve the problems posed by the high proportion of wind power on frequency stability,research on the participation of wind power in the frequency adjustment of low-inertia grids needs to be focused on.This paper analyses the frequency characteristics of low-inertia grids against the background of large-scale wind power access,and the method of wind turbine involvement in frequency management and its synergy with battery storage and synchronous generators is studied accordingly.Based on the traditional system frequency model and the concept of wind power permeability,this paper establishes a frequency analysis model considering the permeability.Next,wind turbines were considered to engage in frequency adjustment,and a model was developed for wind turbines to engage in frequency adjustment with integrated inertia control,and analyzes the system frequency characteristics and response indexes under the two models.Through the simulation platform,it is verified that the increase of wind power permeability will lead to the deterioration of the frequency characteristics of the system,and the frequency dynamic characteristics of the system are improved after the fan participates in frequency modulation.To further enhance the frequency modulation of wind turbines,this paper analyzes and studies the typical frequency eigenvalues of wind turbine under different frequency modulation parameters,dynamically adjusts the frequency modulation parameters by using the fuzzy control principle according to the influence law of parameters on the frequency dynamic characteristics,and completes the optimization of the comprehensive inertia control method of doubly fed fan.Then,simulations were run based on the MATLAB/Simulink platform to confirm the effectiveness of the proposed fuzzy control-based integrated inertia control method for wind turbines.Finally,considering the certain problems faced by single wind power frequency modulation,this paper investigates the way in which energy storage systems can be involved in grid frequency control,and through theoretical analysis of the support role of the joint wind-storage system on frequency,a joint wind-storage frequency regulation strategy is designed to make up for the defects of single wind power frequency regulation using the principle of frequency division.At the same time,an overall frequency control method for systems containing wind-fire-storage is proposed based on the rectification of the thermal regulation coefficients over a range of different frequency fluctuations.By setting the filter time constant and difference adjustment coefficient,the three cooperate to undertake the task of frequency modulation.Finally,the simulation platform is used to verify.According to the findings,it is clear that the integrated frequency regulation control method presented in this paper improves the frequency regulation effect of the system,decreases the frequency regulation stress of synchronous units,increases the level of wind power consumption in low-inertia grids,and is helpful to the stable and economic running of low-inertia power grids. |
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