Numerical analysis of vibrations of cable and tower of electric power transmission lines

Resumo

This article presents preliminary results on the behavior of towers and cables in power transmission
lines using a three-dimensional numerical model. Computational analyses were performed considering the plastic
behavior of ASTM-A36 and ASTM-A242 steels used in the tower. The mechanical model included rigid
connections and fixings, and four vibration modes of the metal tower were obtained: transverse, longitudinal,
torsional, and flexural. To validate the dynamic behavior of the cable, the classical problem of the violin string
was used, verifying that natural frequencies increased with cable tension. Receptance analysis allowed obtaining
displacement curves as a function of wind excitation frequency for different orientations. Critical wind excitation
frequencies were related to the vibration modes of the structure. The geometry and dynamic behavior of the
transmission tower and cable were explored, providing information on vibration frequencies and dynamic response
of the structure under different wind orientations. Four vibration modes were found: transverse, longitudinal,
torsional, and beam bending.