风能风切变指数计算方法的比选研究  

Screening of calculation methods for wind shear exponent

作　　者：徐宝清[1] 吴婷婷[1] 李文慧 

机构地区：[1]内蒙古工业大学信息工程学院,呼和浩特010080 [2]北京天润新能投资有限公司华北分公司,呼和浩特010010

出　　处：《农业工程学报》2014年第16期188-194,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：内蒙古工业大学重点科研基金项目(ZD201227)

摘　　要：为了支持风电场的开发和建设,结合最小二乘法对风切变指数这一重要参数进行了分析研究。根据风切变指数关系式和最小二乘法拟合直线算法,给出5种不同的方法分别计算风切变指数;然后根据计算得出的风切变指数与幂律公式推算已知高度的风速,再利用各自的推算结果与实测风速进行对比,分析其误差,选择较为准确的风切变指数。选用内蒙古乌兰察布市某测风塔共3个测风高度一年内完整的实测数据为例,采用上述方法计算该地区风切变指数,结果表明去除小风速后的数据利用最小二乘法拟合的计算方法和利用风廓线拟合的方法都较为准确;因此,应结合风电场的实际情况综合采用这些方法,选取误差最小的风切变指数。该研究有利于更准确地推算风机轮毂高度的风况,进而能够更加准确地估算发电量和评估风能资源。In order to support the development and construction of wind farms, this paper analyzed and studied an important parameter-the wind shear exponent. Due to the influence of ground roughness, the wind shear exponents of different areas are different; in addition, because of the thermodynamic factor, the wind shear exponents are different even in the same area at different times. Therefore, to obtain an accurate value of the wind shear exponent in a certain area at a certain time, only the local wind-speed data can be used to calculate it. However, because of the complexity of the measured data, there are many methods to calculate the wind shear exponent, and the values calculated by different methods are different. So, in this paper, the methods of calculating wind shear exponent were studied. Firstly, there were five methods to calculate the wind shear exponent using different data sets, including 1） all of the data, 2） the data without wind speeds less than 3 m/s, 3） the data with the annual average wind speed, 4） the data with wind speeds between （15＆#177;0.5） m/s, 5） the wind profile. Among them, methods 1, 2, and 4 calculated wind shear exponent through the least-squares fitting. Method 3 used the annual average wind speed and the exponential formula to calculate wind shear exponent. Method 5 used wind profile fitting to calculate the wind shear exponent. The wind profile reflects the overall level of the wind conditions. Then, with the example of actual wind speed data, and within a complete year on three wind measurement heights at a mast of Wulanchabu in Inner Mongolia, five different wind shear exponents of this area were calculated by the above methods. Finally, according to the calculated wind shear exponents and the power-law formula, the wind speeds of the known height were calculated, and then by comparing the calculated value and actual value, the methods that produce smaller errors were chosen, and at last the more accurate wind shear exponent was obtained. The results showed that du

关 键 词：风能 应用 计算 风切变指数 指数公式 最小二乘法 风速 

分 类 号：TK83[动力工程及工程热物理—流体机械及工程]