Research On Wind Characteristics And Influence On Output Characteristics Of Doubly-fed Wind Turbines

Wind power as a clean and sustainable power generation method because of its suitable for large-scale development and increasingly mature technology to become one of the alternative options for traditional fossil fuels.However,the inherent instability of wind power will cause accurate prediction of wind farm output and power grid scheduling and stability of trouble.The randomness and intermittence of the wind determines the fluctuation of the load and output of the wind turbine.As the output power of the turbine is proportional to the third power of the wind speed,the small change of the wind speed will cause the fluctuation of the unit output.If there are multiple wind turbines installed in a region,the volatility of the output will have a great impact on the overall control of the wind farm and the stable operation of the power grid.Therefore,it is necessary to analyze the influence of wind characteristics on the output characteristics of wind turbine,and establish the operation model of wind turbine to realize the analysis of the output performance of wind turbine under different wind conditions.In this paper,based on field measurement data,a double-fed wind turbine simulation model was built in the MATLAB / Simulink toolbox to simulate the influence of wind speed variation on the output characteristics of the doubly-fed wind turbines.The influence of different wind shear index and turbulence intensity on the output power curve is analyzed according to the wind data.The main contents are as follows:(1)Based on the measured wind speed,the influence of wind shear index on the wind speed and output characteristics of the unit is analyzed.With the change of the height ratio,the wind shear at the same site calculated by different altitude laye rs is different and its variation is more complicated.The measured data show that the relationship between the wind shear value and the height ratio is fitted to a quartic polynomial with good engineering applicability.When the wind speed at the hub heig ht is estimated from the wind shear index and the wind speed measured at the lower level,the measured wind speed data and the wind shear index are selected to be closest to the hub height,and the error between the calculated wind speed value and the meas ured value is the smallest.And the result can be effectively improved by using the fitting wind shear,which can effectively improve the prediction of wind turbine output characteristics.(2)Set up a double-fed wind turbine model in MATLAB / Simulink toolbox to study the effect of pulsating wind on wind turbine output.The response of wind turbines to the wind speed is analyzed by using the step response module to simulate the characteristics of the pulsating wind,the influence of varying wind speed on wind turbine output characteristics is summarized.And the effect of different turbulence intensity on the output parameters of the wind turbine is analyzed for three different working intervals.