新疆达坂城风电场风能资源特性分析

对新疆达坂城风电场的风能资源特性进行了详细的研究。基于在达坂城风电场实测的10m和24m高程的10min平均风速数据,分析了原始风速的分布特性。根据地表风速沿高度呈风剪指数分布的特性,计算了在各个轮毂高度上的风速分布。采用最小误差逼近算法原理,计算了风速韦布尔分布的参数以及平均风速和分布方差。通过对韦布尔分布的分析,计算了各个高度上风电场的平均风功率密度、有效平均风功率密度和可利用小时数等风能资源特性参数,为当地的风能开发提供分析基础。     

内蒙古地区风资源评估与风场特征风速的推导

对内蒙古二十四个地区的风能资源进行评估,得到风谱图.首先提出了利用WAsP软件对1998年至2008年期间内蒙古二十四地区的风资源资料中的基础进行分析;然后利用风速威布尔分布函数和风力发电机组输出功率的威布尔的概率密度函数,求两个函数的极值,推导出切入风速和额定风速的公式.最后以内蒙古六个地区为例,计算不同风资源条件下的切入风速和额定风速.     

测风数据的时间间隔对风速概率分布参数计算的影响

风电场风速概率分布是体现风能资源统计特性的重要指标.文章在认为风速服从双参数威布尔分布的前提下,对于不同时间间隔所记录的风数据,分别应用最小二乘法、平均风速和标准差估算法、平均风速和最大风速估算法求解风速概率分布参数,由此估算出能直接体现风能资源状况的风能特征指标值.比较由风速概率分布推算出风能特征指标的估计值与由记录...     

都昌老爷庙风电场风能资源研究

利用都昌气象局对老爷庙风电场所测的数据,对其风能资源中平均风速、平均风能密度、有效风能密度、有效时数等参数进行了详细的计算和分析.利用威布尔双参数曲线拟合风的频率曲线, 对其两个参数k和c的估算用三种不同方法分别加以探讨并进行误差对比,最终得到老爷庙风电场的风能评估结果.     

基于Windographer的某区域风电场风资源分析评估

根据甘肃省某区域风电场测风塔10 m、40 m、60 m、80 m高度的实测风数据,利用Windographer4.2风资源分析软件计算空气密度、平均风速和风功率密度年内变化和日变化、风速和风能频率分布、风向频率和风能频率方向分布、风切变指数、湍流强度和50年一遇最大风速等指标参数。其计算结果表明测风塔80 m高度年平均风速为6.93 m/s,年平均风功率密度为354 W/m~2,年有效风速(3.0～25.0 m/s)时数为7 200 h以上,盛行风向稳定。60～80 m高度湍流强度在0.072～0.080之间,小于0.12,湍流强度较小。综合判定该区域风能资源较为丰富,符合大型风电场建设条件,适宜进行大规模风电开发利用。     

基于CFD和NCPSO的复杂地形风电场微观选址优化

针对复杂地形条件下风电场微观选址技术难度大的问题,提出一种基于数值计算结果和高效优化方法的微观选址优化算法。将测风数据按风向等分成12个扇区,并利用平均风速和CFD对复杂地形的每个扇区进行数值模拟,得到风电场各扇区的风资源分布,提取轮毂高度处的风速和风向分布。优化中风力机的尾流影响采用Jensen尾流模型,风电场风能计算中风速按照威布尔分布处理,并考虑每个扇区风速的大小、概率密度。目标函数为整个风电场的输出功率倒数的对数,自变量为风力机在给定风电场中的位置坐标,约束条件为地形边界和风力机之间的最小距离,优化算法采用该文提出的改进小生境粒子群算法(NCPSO),优化风力机组微观选址的最优解。该文提出优化算法得到的结果与基于高度的经验布置方法(EX-TH)、基于风能密度的经验布置方法(EX-PH)以及普通粒子群算法(PSO)进行比较,证明在复杂地形条件下所提出方法的可靠性与有效性,并可应用于工程实践。     

逐时风速概率分布研究

风速概率分布及其参数是体现风能资源统计特性的最重要指标之一。以山东省4个风电场测风塔和气象站测风年的逐时风速为样本,采用正态分布、指数分布、威布尔分布、伽马分布和Logistics分布对逐时风速概率分布进行研究,以Akaike信息准则判断概率分布的适用性。研究结果表明,威布尔分布、伽马分布和Logistics分布能更好的拟合小时风速的实际情况。     

风电场风能资源评价两个新参数——相当风速、有功风功率密度

利用风速频率瑞利分布对平均风速进行均一化,提出相当风速的概念;通过对风功率密度进行分析,考虑到风机工作风速区间,提出有功风功率密度概念。为准确评价潜在风电场风能资源状况提供了两个指示性很强的指标。     

风电场测风数据插补方法研究及插补结果偏差分析

为解决在风资源评估阶段,数据插补应用条件及插补结果偏差难以量化、插补算法难以选择等相关问题,通过大量数据模拟实际缺失情况,采用插补方法将数据补全,利用均方误差(MSE)、威布尔分布k值、平均风速、风功率密度、风电机组发电量5个评价指标构建指标体系,与真实数据进行了对比及偏差分析,在此基础上得出了数据插补应用的相关系数水平,并推荐了最优的测风月份及最优的测风数据插补算法。     

陕北典型风能特性分析

该文分析了榆林靖边与定边2处风电场2019年测风塔观测数据,发现两地风速、风向分布具有较强局地性,靖边风电场年平均风速明显小于定边风电场年平均风速,靖边地区风速概率属于单峰分布,定边地区风速分布更加均匀,靖边风电场70 m平均风速呈现V字型分布,定边地区风速分布呈现浅U字型。靖边与定边均呈现出冬季平均风速大,夏季风速最小,风功率密度冬春季最大,夏秋季明显降低的分布特点,且两地70 m风功率密度与陕西年负荷在春、夏、秋3季均呈现较明显的反向分布。     

Wind power potential and characteristic analysis of the Pearl River Delta region, China

Wind power potentials of the Pearl River Delta (PRD) region have been statistically analyzed based on the hourly measured wind speed data in four islands. The hourly and monthly wind speed and wind power density are assessed to have remarkable variations, and the Weibull distribution function has been derived from the available data with its two parameters identified. The wind power and operating possibilities of these locations have been studied based on the Weibull function. The wind power potentials of these sites were found to be encouraging; however, the wind power at different site varies significantly, so attention should be paid to the wind conditions as well as the site terrains in choosing the wind farm sites.     

Wind characterization analysis incorporating genetic algorithm: A case study in Taiwan Strait

In this paper, the genetic algorithm (GA) is originally applied to compute the Weibull parameters for wind characterization analysis, in which an objective function required in GA for searching optimization solution has been first defined as well. Wind data analyzed are observed at a wind farm in the Taiwan Strait from 2006 to 2008. To accurately describe wind speed distribution three kinds of probability density functions are compared, i.e. the Weibull, logistic and lognormal functions. Statistical parameters including the max error in the Kolmogorov-Smirnov test, root mean square error, Chi-square error and relative error of wind power density are considered as judgment criterions. The results show that GA is a useful method, there is about 33% time saving when compared with conventional iteration method. Weibull function describes best the wind distribution, regardless of time periods. Accordingly, wind power density, availability factor and electrical energy output from an ideal turbine are assessed using the Weibull parameters; utilization rate of wind energy for the currently used turbine is discussed. Further the wind energy compensates very well with solar energy; when solar radiation is down in winter and spring, the wind power becomes greater; energy ratios for each month are calculated lastly.     

基于PWMM的三参数Weibull分布参数外推方法的研究

为提高低风速区分散式风电项目的风资源评估精度,降低测风成本,在对三参数Weibull分布参数估计和外推的研究基础上,提出基于概率加权矩法(PWMM)的三参数Weibull分布参数垂直外推方法。利用较低高度处风速统计的概率加权矩,经垂直外推得到平坦地形、较高高度处风速Weibull分布的参数,进而得到Weibull分布函数和风功率密度。算例分析表明:基于PWMM的三参数Weibull分布参数垂直外推法在平坦地形不同测风点处有一定的适用性外推较高高度处风速Weibull分布的参数,可有效体现平坦地形低风速区的风速分布特征,提高风功率密度评测精度。     

Potential for wind generation on the Guyana coastlands

Guyanas dependence upon imported petroleum fuels can only be offset by the sustained exploitation of its indigenous resources. With its populated coastlands exposed to the northeast trade winds and a history of small-scale wind energy utilisation wind is one such potential energy source. In this study, the coastal wind regime is analysed and historical data from a coastal weather station are used to estimate the potential for wind generation. It is found that a hybrid Weibull probability density function best describes the annual wind speed frequency distribution at the reference height of 10.67 m. With an annual mean wind speed of 5.8 ms, an energy pattern factor of 1.41, and an annual average power density of 159 Wm², this distribution represents a class-3 wind resource, suitable for most wind turbine applications. Site analysis and observed trends in coastal wind availability suggest the strong likelihood of a greater wind resource in more open locations. In view of its apparent potential for wind farm operation, a comprehensive, wind resource assessment programme is recommended for the Guyana coastlands.     

A particle swarm optimization for wind energy control problem

The control problem of a wind turbine involves the determination of rotor speed and tip-speed ratio to maximize power and energy capture from the wind. The problem can be formulated as a nonlinear programming problem with the annual energy generation as the objective function. The wind speed distribution is modeled as the Weibull distribution. The Weibull shape and scale parameters are assigned to be stochastic in response to limited wind data and variability nature of the wind. It is proposed to apply particle swarm optimization to solve for optimum rotor speed under fixed-speed operation and optimum tip-speed ratio under variable-speed operation. The optimum rotor speed varies with the wind speed distribution, while the optimum tip-speed ratio does not depend on the wind speed distribution. It can be concluded from the simulation results that both the wind power and energy are more dependent of the Weibull scale parameter than the Weibull shape parameter. This implies that the wind power and energy are more dependent of the mean wind speed than the speed distribution.     

基于TPNT含风电场发输电组合系统可靠性评估

为克服含风电场可靠性评估中需已知风速分布函数的缺点,提出了一种基于三阶多项式正态变换(TPNT)的非序贯蒙特卡洛模拟法评估含风电场发输电系统的可靠性。在已知风速历史数据或风速分布函数的情况下,通过TPNT构建风速随机变量与标准正态分布变量的关系,进而利用标准正态分布函数的性质产生具有任意数量的具有指定相关性的风速样本,并应用于风电场接入的发输电系统可靠性计算中。通过算例分析验证了TPNT应用于发输电系统可靠性计算中的适用性。在此基础上,从风速相关性、额定容量、风资源强度和风电场位置四个角度分析了风电场接入对可靠性的影响。为含风电场发输电系统可靠性的评估提供了新思路。     

考虑多参数影响的风电场多状态出力概率性评估

大规模风电并网会对电力系统的可靠性带来严峻挑战,其出力的随机性也会对电力系统可靠性评估带来难题。为了准确地对风电场出力进行评估,结合风速的随机性,考虑了风电机组的故障、降额和随机投产状态以及风速分布的威布尔参数对风电场出力的影响,建立了风电场多状态出力的可靠性模型;基于蒙特卡洛法对风电场的有功出力进行了概率性评估,并分析了不同状态数、不同降额概率、故障停运概率、随机投产率及不同的风速分布威布尔尺度参数和形状参数等对评估结果的影响。仿真结果表明,所建模型切实可行,能有效地对风电场出力进行评估。     

A survey on the assessment of wind energy potential in Egypt

In this paper, wind data obtained from the Egyptian Meteorological Authority are used to assess monthly and annual wind power and wind energy. The study is based on data from 15 anemometer meteorological stations, distributed all over Egypt and covering a period ranging from 1973 to 1994. For these stations the wind data are summarized. The wind energy potential at the 25 m height was obtained by extrapolation of data at 10 m using a power-law expression. The result presents the mean wind energy density estimates and potential for application in Egypt. The analysis showed that along Red Sea coasts, the annual wind energy flux is found to be high, which indicates that these coastal stations are possible locations for wind energy utilization. On both the Mediterranean coast and in the interior parts of Egypt, some stations are of low available wind energy, while others are found to be rather high. Also, the two Weibull distribution parameters have been estimated from the wind speed data for some meteorological stations and the wind power density is calculated using the values of these parameters.