Overhead Conductor Vibrations and Control Technologies

Wind-induced conductor vibrations are Aeolian vibration, galloping and sub-span oscillation. Aeolian vibration is caused by an alternating wind force, which arises from a pressure difference associated with a regular formation of vortices behind a conductor. Galloping is a low frequency, large amplitude, wind-induced vibration of both single and bundle overhead conductors, with a single or a few loops of standing waves per span. It is caused by moderately strong, steady crosswind acting upon an asymmetrically-iced conductor surface. Sub-span oscillation is produced by forces from the shielding effect of windward sub-conductors on their leeward counterparts. It is particular to bundle conductors. This paper describes the three forms of conductor vibrations and the control technologies from utilities´ practical point of view. As an example, a design consideration is discussed. This paper also captures the challenges of vibration control on High Temperature Low Sag conductors, based on experiences in North America.