Determination of early failure sources and mechanisms for Al 99.7% and Al–Mg–Si alloy bare conductors used in aerial transmission lines

Abstract In this article, early failure reasons and their sources for the bare aerial transmission line conductors have been presented with a combination of measuring data on wear tendency of their components and analyzing of collected samples due to processing damages and continue cast defects onto wires produced by 99.7% EC grade Al and Al–Mg–Si alloys. Nominal service life of aerial conductors is 30 years. However most of them are failed early. Essential source of the failure depends on environmental conditions and manufacturing process. After installation of conductors to trusses, the fretting phenomenon between strands under greased and non-greased applications is triggered due to fluctuation of bending, tension and torsional stresses by wind and dead loads of conductors. Environmental forcing functions cause working of surfaces of defected and processing damaged wires each other with small displacements and create grinding of small particles and finally fretting. Samples collected from the aerial conductor plant including processing defects and damages were illustrated and interpreted in the article deeply. Additionally, tribological behaviors of conductor wires were also investigated with different parameters under grease lubrication and dry friction conditions. Results were presented in graphics and figures in details to indicate the early failure reasons which were mainly related to manufacturing process and tooling used in processing of them.