Nonlinear Dynamic Analysis of Transmission Line Cables under Synoptic Wind Loads

Abstract

This paper presents the structural behavior of transmission line cables under nondeterministic dynamic wind loads (atmospheric turbulence), considering aerodynamic damping and geometric nonlinearity. A numerical methodology was developed using commercially available finite-element analysis software and applied to 32 case studies considering different spans and wind velocities. The maximum responses obtained in the dynamic simulations were compared with the results from (1) quasi-static analyses considering the mean velocity, and (2) quasi-static analyses performed according to the procedures established in a range of current standards and codes. The first comparison highlighted the importance of considering the dynamic response in cables subjected to wind loads. Among the Brazilian codes evaluated, one code showed results considerably lower than those obtained through dynamic analyses, with maximum differences of 28%. In contrast, another code showed maximum differences of approximately 10% and, in the absence of Brazilian recommendations for transmission lines projects, it can be used as a reference. A third code showed good agreement with the numerical results, indicating it to be the most appropriate code for the determination of wind forces in transmission lines cables.