#IGRE฀3CIENCE฀฀%NGINEERING฀s฀.ｪ฀/CTOBER฀ 17 Abstract This paper presents the experimental results of bending stresses on aluminum conductors, steel reinforced (ACSR), rigidly clamped and subjected to Aeolian vibration in an indoor span. The tests have been conducted on four different conductors widely used by a utility to determine the relationship between bending stress and bending amplitude, which is an important parameter for conductor fatigue. Test results show a non-linear dependence on the bending amplitude; and, particularly for smaller size conductors, this differs significantly from the bending stresses as calculated by the Poffenberger-Swart formula. Bending amplitude and bending stress data were analysed and plotted using curve-fitting with third-order polynomials, which gave excellent predictions of the experimental data and which may be used for the assessment of the vibration severity for these conductors. 1. Introduction Wind-induced conductor vibrations and particularly Aeolian vibrations, are still a major issue of concern to transmission-line engineers, as they can cause, if not detected and mitigated, severe conductor damage [1]. For their assessment, a simple calculation method of the relationship between the so-called bending amplitude and bending conductor stress, derived from the pioneer- ing work of Poffenberger and Swart, [2] is often used and accepted as the de facto industry standard, [3,4] even though there are often discrepancies between this theory and actual tests. This is understandable, as this formula does not adequately take into account the intrinsic stress regime of the individual conductor wires during the bending process. Some 20 years ago, the mechanical model of a conductor undergoing a change of stress regime upon bending, as is the case for Aeolian vibrations, was described in detail [5]. The model was based on the adequate analytical description of the interlayer friction, and could thus explain the non-linearity observed during measurements of bending stress vs. bending amplitude [6]. This theory was satisfactorily correlated with static experiments on ACSR Cardinal (54 Al. /7 St.). Since then, several research studies have addressed this issue, an excellent summary being published in [7]. Over the last years, and owing to the advances in simulation tools, notably the finite-element method (FEM), many attempts have been made to determine the stresses in the individual conductor wires when the conductor is subjected to quasi-static bending. While the results from such simulations look promising, their experimental validation proves difficult, as the stress regime of the conductor wires is difficult to assess. For this reason, and as in most utilities the number of different conductors employed in line construction is limited, an alterna- tive method proposed in this paper, is to determine experimentally the bending stress/bending amplitude relationship only for these conductors. This may be done in an indoor test span following the test procedure described in the recent IEC Standard [8]. KEYWORDS Aeolian vibration, bending amplitude, bending stress, curve fitting, vibration tests. * danielkubelwa2010@gmail.com