Galloping database on single and bundle conductors prediction of maximum amplitudes

A database of 166 observations of galloping on single, twin, triple and quad bundle lines has been analyzed. The database is sufficiently detailed to define the variation of maximum amplitudes of galloping motion for single conductors in 50 to 450 m spans, and for twin and quad bundles in 200 to 450 m spans. Conventional design expectations are exceeded, for maximum galloping motions on short spans, and through the existence of single loop galloping on long spans. New proposals are presented for estimating the maximum galloping, motions for spans without galloping controls. The best fit numerical model for single conductors uses the peak to peak galloping amplitude over subconductor diameter, versus "conductor span parameter", the conductor diameter over the sag. The best fit model for bundle conductors uses the peak to peak galloping amplitude over subconductor diameter as a function of the "conductor span parameter".