Behaviour of Transmission Line Conductors under Tornadoes
Abstract
Transmission line (TL) structure failures caused by tornadoes have been observed in multiple countries around the globe. The objective of this study is to develop an accurate load case that can simulate the critical tornado forces transmitted from the TL conductors to the towers. In order to achieve the goal, three different tornado wind fields, which were previously developed using computational fluid dynamic simulations, are considered. The tornado wind field provides the most critical forces on the TL conductors is determined and considered to obtain the critical load cases. Using the critical wind field, parametric studies are conducted to identify the tornado position that generates peak longitudinal forces. A parametric study is conducted on two different transmission line systems to assess the influence of conductor parameters on the longitudinal forces. Results of the parametric study are used to develop charts, which together with a three-dimensional interpolation procedure can estimate the critical conductor longitudinal forces on the towers.