Wind-induced vibration and fatigue in transmission line conductors: an analysis of excitation mechanisms and design criteria for spacers and dampers

Abstract

Conductor failures in transmission lines associated with dynamic loads rarely result from a single overload. They come from the accumulation of low-amplitude bending cycles over years of operation. This paper reviews the wind-induced excitation mechanisms acting on conductors and bundled conductors and relates them to the normative criteria for the design of spacers and dampers. Aeolian vibration, linked to von Kármán vortex shedding and the lock-in phenomenon, and subspan oscillation, an aeroelastic instability specific to bundles, are discussed. The paper builds on a principle already established in the field, the energy balance method: conductor fatigue arises from the imbalance between the energy injected by the wind into the system and the capacity of the devices to dissipate it. The contribution lies not in this principle, but in using it as a guiding thread to systematize the roles of standards IEC 61854, CIGRÉ and IEEE Std 1368 in design and field verification, bringing the physics of the phenomena closer to practical engineering decisions. It is concluded that the positioning of spacers and dampers is not a constructive detail, but a design decision that defines the service life of the line.