Dynamics of a Guyed Transmission Tower System

A free vibration analysis is presented for a transmission line. The guyed supporting towers are somewhat novel, consisting of a Y-shaped frame made of hollow steel sections. Transverse vibrations in both the conductors and the guy-wires were modelled by using special parabolic cable elements. The lowest frequency modes primarily involve conductor motions but are affected by insulator swing and by coupling with the towers. It was determined from such mode shapes that loads transferred to the towers during galloping are not catastrophic, at least when the lines are iced lightly.