Research On Optimization Of Active Regulation Of Wind Farm Under Fatigue Constraint Of Wind Turbine Blades

With the continuous expansion of the scale of wind power integration,the grid’s requirements for wind farm participation in regulation are increasing.When wind turbines follow the power grid dispatching instructions through pitching movements and adjust their output quickly,due to the effects of wind speed randomness and dynamic changes in the state of the unit,blade defects continue to accumulate,which can cause blade performance degradation and fatigue over time damage.This paper focuses on the problem of high power generation costs caused by the fatigue damage of each unit when the wind farm participates in the power grid dispatch,and the difficulty of the coordination of wind farm fatigue optimization and active power control.The optimization method of wind farm active power regulation under wind turbine blade fatigue constraints is studied.On the premise that the active power of the wind farm quickly responds to grid fluctuations,the uniformity of fatigue damage of each unit of the wind farm is improved,and the probability of wind farm failure and temporary maintenance are reduced.First of all,the aerodynamic model of the impeller and the power output model of the wind turbine are elaborated in this paper,and the wind energy conversion process of the fan under ideal conditions is analyzed based on the leaf momentum theory,and the law of blade vibration characteristics with the active output of the wind turbine is deduced,The dynamic vortex wake model is embedded in the leaf element momentum theory to solve the blade aerodynamic performance during the pitch process,and the numerical method based on the singularity theory is used to calculate the unsteady blade load during the dynamic pitch process.Secondly,to study the nonlinear fatigue quantification method of wind turbine blades,to characterize the interaction mechanism between the loads in the dynamic damage evolution of the pitch by the square of the multi-level load stress ratio before and after,and to optimize and improve the evolution equation of the first-level load damage.The fatigue quantification method based on Ye Duyi’s model improved under different working conditions,and the accuracy and effectiveness of the proposed method were verified by simulation analysis.Finally,for the problem that the existing wind farm active control strategy will cause frequent blade movement at high wind speeds,this paper proposes an optimal control strategy for wind farm active adjustment under blade fatigue constraints,taking into account the wind farm power adjustment effect and the operating conditions of each unit.This method makes full use of the adjustment margins provided by each wind turbine,and preferentially adjusts the wind turbine with a small amount of fatigue damage,which can effectively reduce the pitch frequency and amplitude of the fan,reduce blade fatigue during pitch,and extend the operating life of the fan.The effectiveness of the proposed optimization is verified through simulation.