The peak factor of dynamic wind loads on double-span conductors: insights from aeroelastic model tests

Abstract

Dynamic wind loads on transmission line conductors are critical for designing power transmission systems subjected to strong winds. In practice, quasi-static theory is applied to compute these dynamic loads, using a peak factor defined as the ratio of mean extreme response to response standard deviation. This factor quantifies the maximum structural responses caused by dynamic wind forces. Current engineering standards typically derive the peak factor for conductors from the Gaussian assumption, a premise that lacks rigorous validation, and its prescribed value varies significantly across wind load codes and standards. To address this gap, this paper develops an aeroelastic model of double-span, single-column conductors and conducts wind tunnel tests to assess the validity of existing assumptions and determine the peak factor under strong wind conditions. Furthermore, experiments on double-span, multi-column conductors are performed to examine the influence of aerodynamic shading and asynchronous pulsations between adjacent conductors on both the peak factor and wind load distribution. Findings provide experimental validation of Gaussian-based peak factor derivation for dynamic wind loads on conductors, yielding a measured peak factor of approximately 3.6. While interaction effects between conductors have negligible impacts on the peak factor and mean wind loads, they significantly reduce dynamic wind loads.