Eijiro Hongo

Full-scale measurements of wind-induced vibration of a transmission line system in a mountainous area

This paper clarifies the characteristics of wind and wind-induced vibration of an electrical transmission tower installed on a mountainous area, based on full-scale data obtained at wind speed of less than 25 m/s. The data was collected between 1991 and 1993. As a result, it can clearly be seen that difference of wind direction has a strong influence on wind characteristics. The vibration characteristics of the tower with conductors are strongly influenced by the behavior of the conductors. The aerodynamic damping of the conductors plays an important role in their total damping. The response values for acceleration, strain of the tower with conductors, and tensile forces of conductors increase in proportion to the power of the wind speed. In general, the value of each power index is less than 2.

Wind response analysis of a transmission tower in a mountainous area

Since 1991, the authors have been observing wind in a mountainous area and wind responses of a large power transmission tower constructed in this area. The purpose of these observation is to clarify the wind characteristics and wind responses of power transmission towers. This paper describes the wind characteristics and the wind responses of this transmission tower obtained from full-scale measurements. A wind tunnel test was also conducted on a two-dimensional mountain to investigate the flow around it. Finally, a wind response analysis was conducted on the transmission tower on the basis of these examinations. The wind response analysis results for the blow-down flow on the leeward slope of the mountain corresponded closely with the measurements. This shows that the evaluation of the blow-down angle is also important in the wind response analysis of the transmission tower in the mountainous area.