Simulation Calculation Of Wake Wind Speed Reduction And Output Power Of Wind Turbine

With the increasing scale of wind farms and the increasing number of wind turbines,the wake effect of wind turbines is the main reason for the decline of wind power generation capacity.Adjustment of the relative position between upstream and downstream WTs(Wind Turbines)can significantly improve the wake effect on the output of downstream WTs.The influence of the wake of upstream WT on the output power of downstream WT is related to axial distance,axial deviation and height difference.Most of the current studies are qualitative analysis of the influence of axial distance,axial deviation and height difference on the output power,but there are few studies on comprehensive quantitative analysis.In this paper,the coupling strength between WTs is studied by the ratio of the output power of the downstream WT to the upstream WT.The following studies are carried out in this paper:(1)The SST k-ω turbulence model based on the RANS method was used to calculate the flow field around the wind field,and the output power of the WT under different incoming wind speeds were simulated,whose results are compared with the theoretical output power value;The wake radial velocity distribution of WT with different incoming wind speed is analyzed,and the influence of incoming wind speed on wake characteristics is studied.(2)Taking double WTs in tandem,staggered,and high-low distribution as the research object,the wake interference effect is numerically simulated,and the influence of axial distance,axial deviation,and height difference on output power under different wind speeds is discussed.The goal is to obtain the quantitative relationship expression of the output power ratio of the downstream and upstream WTs with the change of the distance between double WTs under different wind speeds.(3)The output power ratio of wind turbine under different wind conditions is calculated by using the output power calculation formula in this paper,and compared with the output power recorded by SCADA,which can better quantitatively reflect the magnitude of coupling strength.Fluent was used to numerically simulate the wind speed reduction curve of the "coupling element" WT.The wind speed reduction curve behind the wind wheel was transformed into the wind speed reduction curve in front of the wind wheel,which was compared with the numerical simulation curve,and the numerical simulation results were revised.The relationship expression for calculating the influence degree of wake disturbance is proved by examples to be practical,accurate,and it has high robustness.It can be used to implement collaborative optimization control strategy for in-operation wind farms to achieve efficiency enhancement of wind farm.It can be used for wind farm design check and provide guidance for the layout of wind power plant.