A benchmark between two different numerical models for ice galloping prediction

Galloping is a wind-induced phenomenon which can lead conductors of transmission lines to instability due to the presence of ice accretions. The paper presents results obtained with two different numerical approaches used to estimate galloping amplitudes on overhead transmission lines. The benchmark case relates to a 400 m single span of four-bundled conductor. A triangular shape of ice, whose aerodynamic coefficients are known by previous experiments in the wind tunnel, is considered as applied to the conductors. The two numerical models described in the paper are based on significantly different approaches even though both use the quasi-steady theory (QST) to reproduce the motion dependent aerodynamic forces. The first model relies on a full non-linear FE model running in time domain, while the second is mainly based on the energy balance method. Despite the different approach in modelling, the estimation of galloping amplitudes considering different ice shape configurations matches with a maximum error of 11 % in the estimation of the maximum vertical amplitude reached at midspan. Consequently, the two approaches can be employed to optimize the configuration of anti-galloping devices on a transmission line. Moreover, this work can represent a robust benchmark for assessing the validity of newly developed galloping models.