摘要
This paper analyzed time-series variation and spatial distribution characteristics of wind resources at the eastern edge of Qaidam Basin based on the wind resources gradient automatic observation system. Wind resources are relatively abundant in the study area, the cumulative number of hours of wind speed between 3–25m s -1 are more than 6600, equal to 275 days, exceeding 75% of total annual hours. Advantage wind velocity spectrum was in the scope of 3–9m s -1 at all gradients and the peak value of wind speed was 4–6m s -1 . Differences in the wind speed frequency distribution at other gradients were not apparent except for the 10m gradient. Compared with other layers, the occurrence frequency of small wind at the level of 10m was higher, while the occurrence frequency of wind speed between 6 and 12m s -1 was higher at other layers. The advantage wind direction in this area was northwest and the wind speed difference was not obvious. Wind speed and wind power density gradually increased with the increasing height, and differences among sites were apparent. The average wind turbulence intensity was 0.199 at each layer and the average shear index was 0.075; turbulence intensity and shear index gradually reduced from over a 10–70m gradient. Turbulence intensity had the same variation tendency as local temperature, whereby a high temperature corresponded to high turbulence and low temperature to low turbulence. The variation tendency of shear index was opposite to that for turbulence intensity; turbulence intensity gradually decreased from lower layers to top layers and shear index was most obvious between 10–30m. Turbulence intensity at each site at each level was between 0.10–0.25, and of medium intensity. These data will provide a technical gist for the layout of wind farms and the utilization of wind power resource at ground level throughout the study region.
基于风资源梯度自动观测系统,对柴达木盆地东缘地区风资源时间变化及空间分布特征进行了分析,结果表明:(1)研究区域具有较为丰富的风资源,3-25 m s-1之间风速累计时数平均超过6600h,也即275d,超过全年总时数的75%。从各梯度来看,随高度增加累积时数总体增加,小风时越往低层风速累计时数越大,大风时越往高层风速累计数越大;各分析站点中戈壁(GB)<3 m s-1风速时数相对最高,诺木洪(NMH)相对最低,≥3 m s-1风速时数正好相反;有效风速累计小时数小灶火(XZH)各梯度间差异不大,戈壁(GB)总体相对最小。(2)各梯度优势风速谱域基本处在3-9 m s-1范围,峰值风速出现在4-6 m s-1之间;除10 m梯度外,其余各梯度风速频率分布差异不大。相比较其它各层,10 m高度层小风出现频次较高,其余层6-12 m s-1的风速出现频次较高。(3)从不同方位风速及风功率密度情况来看,除戈壁(GB)外,总体优势风为西北风;除诺木洪外,总体风速差异不大。(4)随高度增加风速和风功率密度逐渐增大;但各站点之间差异较大。从逐月情况来看,小灶火(XZH)5-8月份平均风功率密度较大、诺木洪(NMH)和戈壁(GB)分别在4月和8月呈现出两个峰值、快尔玛(KEM)则在冬春季节风资源较丰富,而在夏季较贫乏;从逐小时情况来看,小灶火(XZH)和诺木洪(NMH)呈现出伴随地面温度升高风功率密度逐渐降低的趋势,戈壁(GB)和快尔玛(KEM)则正好相反。(5)各层风平均湍流强度为0.199,平均切变指数为0.075,自10-70m梯度湍流强度和切变指数总体自低层到高层逐渐降低。时间变化情况为,湍流强度与当地气温变化趋势基本一致,即高温对应高湍流,低温对应低湍流;切变指数变化趋势基本与湍流强度相反;各梯度间湍流强度自低层向高层递降,切变指数在10-30m层间最明显。各站点各层次湍流强度基本在0.1-0.25之间,属中等强度;切变指数各站点各层之间差异较大,总体小灶火(XZH)最小,诺木洪(NMH)最大,而且小灶火(XZH)底层为正切变,高层为负切变。期望通过本研究为该地区风电场布设及近地面层风能资源利用提供技术依据。
基金
Public welfare meteorological industry specific "China’s wind power exploration evaluation and safety operation of meteorological guarantee technology research" (GYHY200806016)
