高海拔输电线路走廊风场实测及湍流特性研究

Wind field observation in transmission line corridors in high altitude regions and the study on turbulence characteristics

在海拔高度为4 500 m的西藏那曲镇高山平原地貌建立了两两间距为10 m、20 m和30 m的4点位同步脉动风速实测系统,获得了持续1.5年的高海拔地区连续大风风速样本,10 min平均风速和脉动风速最大值分别达到33.6 m/s和45.0 m/s以上,实测顺风向湍流强度和横风向湍流强度的均值分别为0.134和0.123,介于DL/T 5551-2018《架空输电线路荷载规范》规定的A类地貌和B类地貌湍流强度之间。基于任意两个测点的同步脉动风速,计算了顺风向脉动风速分量沿导线方向的空间相关系数及湍流积分尺度,广义极值模型可以较好地反映高风速样本湍流积分尺度的概率分布。实测样本风速越高,湍流积分尺度均值越大,当样本风速限值取8.0 m/s和20.0 m/s时,湍流积分尺度均值相差22.5%。20.0 m/s以上高风速样本的湍流积分尺度均值为106.96 m,约为DL/T 5551-2018《架空输电线路荷载规范》规定值50 m的2.1倍,导地线风荷载增大约6.1%,即高海拔高山平原地貌导地线风荷载可能会被低估。

A four-point synchronous fluctuating wind speed measurement system with horizontal pair intervals of 10m,20m and 30m was established in a plain landform terrain site of Nagqu town,Xizang,at an altitude of 4500m.Continuous records of wind speeds for 1.5 years at this high altitude site were obtained.The maximum average wind speed in 10 minutes and the fluctuating wind speed reached 33.6m/s and 45m/s,respectively.The measured mean values of longitudinal and transverse turbulence intensity are 0.134 and 0.123,respectively,which are between the turbulence intensity of the Exposure Category A and the Exposure Category B specified in DL/T 5551-2018.Based on the synchronous fluctuating wind speed of any two measuring points,the spatial correlation coefficient and turbulent integral scale of the downwind fluctuating wind speed component along the conductor direction were calculated.The generalized extreme value model can better reflect the probability distribution of turbulent integral scale based on high wind speed samples.The higher the field observation sample wind speed,the larger the average turbulence integral scale.When the wind speed sample limit is set as 8m/s and 20m/s,the difference between the average turbulence integral scale is 22.5%.The average turbulence integral scale with high wind speed samples above 20m/s is 106.96m,which is 2.1 times of the 50m specified by DL/T 5551-2018,and the wind load acting on the wires increases by about 6.1%.The wind load on the wires in the high-altitude plain landform may be underestimated.