风切变指数在风电场风资源评估中的应用

以内蒙古地区3座70m高测风塔连续2年的实测数据来分析风切变指数的变化,结果表明:1)不同高度梯度的风切变指数受地面粗糙度及周围地形地貌的影响较大。2)计算相邻高度的风速时,采用相邻高度间的风切变指数计算得到的结果较好;计算相差较大的高度间风速时,采用拟合曲线得到的风切变指数计算得到的结果较好。3)利用3～25m/s的风切变指数计算各月风速及年均风速结果都与实测值最接近;而利用全部风速数据的风切变指数计算统计各月风速往往比实测值偏大;利用3～25m/s拟合曲线得到的风切变指数统计各月风速比实测值偏小。

Application of Wind Shear Index in the Assessment of Wind Resources of Wind Farm

This paper presents a study on changes of the wind shear index based upon the measured data of three 70-meter-high wind towers for 2 consecutive years in Inner Mongolia. The result of the study shows as below: 1) the wind shear index at the different height gradient is greatly affected by ground roughness and the surrounding topography. 2) in calculating the wind speed adjacent to a certain height, adoption of the wind index between the two adjacent heights would result in a better output, while in calculating the wind speed difference between two heights of a large distance, adoption of the wind index acquired by the fitting curve is preferable. 3) the monthly and yearly wind speeds worked out by means of the 3~25 m/s wind shear index are the closest to the actually measured data, while using of the wind index of all wind speed data to calculate the monthly wind speed would result in large differences from the measured data, the monthly wind speed as calculated by means of the wind index acquired by the 3 ~25 m/s fitting curve is smaller than the measured value.