Galloping Suppression of Iced Transmission Lines by Viscoelastic-Damping Interphase Spacers

Abstract

Galloping of iced conductors is a kind of self-excited aeroelastic vibration at low frequency and large amplitude causing various damage to transmission tower-line systems. This paper proposes viscoelastic-damping interphase spacers (IPSs) for reducing or mitigating galloping of multiphase transmission lines. Equations of galloping motion are established for a simplified model of two-phase conductors connected by viscoelastic-damping IPS. The multiple-scale method (MSM) is then used to derive an analytical solution of the galloping amplitude with validation from both the finite-element method (FEM) and numerical solutions. Based on analytical solutions, the effects of structural dynamic parameters of conductors and viscoelastic-damping IPSs on galloping critical wind conditions and galloping amplitudes are investigated in a parametric space as well as in the consideration of transmission engineering practice. It is found that there exists an optimal damping ratio of viscoelastic-damping IPSs to achieve the maximum critical wind speed of galloping for the two-phase conductor system. The antigalloping effect of an IPS is largely dependent on the frequency ratio of a two-phase conductor as well as the relative stiffness of IPSs.