Dynamic analysis of transmission tower-line system subjected to wind and rain loads

In order to study the dynamic response of transmission tower-line system induced by wind and rain loads, the calculating method of wind and rain loads acting on the transmission conductor is presented. The wind tunnel test, conducted by Kikuchi et al. (2003), is introduced to determine the drag coefficient under both wind and rain excitations, which is a key parameter to estimate the wind and rain loads for the transmission conductor. Then the three-span conductor and tower-line system are modeled to perform the dynamic analysis subjected to wind and rain loads, of which the results demonstrate that the maximum percentage of average displacement induced by the rain loads relative to the wind loads can reach to 22.00%, indicating strongly that the effect of rain load on the response of tower-line system is not negligible. Meanwhile the influence of wind attack angle on the response of tower-line system induced by wind and rain loads is investigated, and the results show that the most unfavorable wind attack angle is 90° and the rain load has no effect on the most unfavorable wind attack angle. The conductors made up of trapezoidal wires are used to examine the effects of wind and rain loads, and therefore some of the models and findings of the present contribution may not always be applicable. All in all, it can be stated that the rain load has an important effect on the response of tower-line system and should be given more attention.