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

A four-point synchronous fluctuating wind speed measurement system with horizontal pair intervals of 10 m, 20 m,and 30 m was established in a plain landform terrain site of Nagqu Town,Xizang,at the altitude of 4 500 m. Continuous records of wind speeds for 1. 5 years at this high-altitude site were obtained. The maximum average wind speed in 10 min and the fluctuating wind speed reached 33. 6 m/s and 45. 0 m/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 Load code for the design of overhead transmission lines. 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 8. 0 m/s and 20. 0 m/s, the difference between the average turbulence integral scale is 22. 5%. The average turbulence integral scale with high wind speed samples above 20. 0 m/s is 106. 96 m, which is approximately 2. 1 times of the 50 m specified by DL/T 5551^2018 Load code for the design of overhead transmission lines,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. © 2024 Chinese Vibration Engineering Society. All rights reserved.