Research On Wind Farm Flow Field And Calculation Model Under Typhoon Condition

China’s southeast coast has abundant wind resources,and a large number of wind turbines are distributed in this area,forming coastal land wind power and offshore wind power,which is an important part of my country’s grid-connected capacity.However,coastal areas are often invaded by typhoons.Abrupt wind direction,transient wind speed and extreme turbulence during the landing process of typhoons are important factors that cause damage to wind turbines.Therefore,the study of flow field analysis and calculation models under typhoon conditions is important for wind power in coastal areas.Especially important for the field.This paper studies the characteristics of the flow field of an offshore wind farm in Zhejiang during the period from 00:00 on August 7th to 23:00 on August 10th under the influence of Typhoon No.8 in 2009.The model is calculated to obtain the reliability of the wind speed distribution in the vertical direction,so that it can be applied to the destructive assessment of typhoons and the design of wind turbines.First,use the wind measurement data at four heights of 50m,70m,100m and 120m measured by the ultrasonic wind meter of the wind farm,and study the wind direction,wind speed,turbulence intensity and other parameters with a time interval of 10min.It is found that the typhoon has a greater impact on the parameters:When the typhoon made landfall 10 minutes,the average wind direction changed significantly,and the average wind speed of 10 minutes decreased significantly.The turbulence intensity fluctuated greatly after landing,and the turbulence intensity at a height of 50m even reached more than 50%.At the same time,it was found that the wind turbines of the wind farm under the action of the typhoon were most affected by the intensity of turbulence.Then use the observation data to use the logarithmic wind profile equation and the Gryning wind speed profile model of the three-term mixed length model,and use different calculation methods to calculate the average wind speed at the four heights.When comparing the simulated calculation results with the measured wind speed,it is found that there is a difference The calculation deviations of the mathematical wind profile equation and the Gryning wind speed profile model of the three-term mixed length model are both within 1.5%,and the calculation accuracy of the simultaneous fitting of friction speed and roughness length using observation data is higher.Finally,use the path information recorded in the International Climate Management Best Path File and the wind field model based on the gradient wind principle to calculate the average wind speed of the wind farm at a height of 10m in 10 minutes,and use the exponential law to calculate the wind speed at a height of 50m,70m,100m,and 120m.The calculation and comparison with the measured value verify the feasibility of using the wind field model to simulate the wind speed at different heights.