Assessment of the fatigue failure of an All Aluminium Alloy Cable (AAAC) for a 230 kV transmission line in the Center-West of Brazil. (March 2016) - Kalombo, R.B.
Abstract: The aim of this work was to conduct an evaluation on the causes for the premature fatigue failure of an AAAC 900 MCM conductor used in a 230 kV transmission line located at the Center-West of Brazil. Each phase of the line had a double cable configuration separated by vertical rigid spacer clamps. To carry out the analysis, vibration recorders were installed on the spacer clamps at two different positions in the span and fatigue tests on the cable were conducted. The Miner's rule was applied and the remaining life of the cable was estimated to be greater than 33 years. The fact that the actual life of the cable is much smaller than the estimated one was associated to the conjoint action of three factors: (i) the use of rigid spacer clamps between the two conductors; (ii) the choice of an AAAC conductor (whose fatigue resistance proved to be significantly less than that of an ACSR) and (iii) the existence of a high frequency laminar wind regime. To avoid new failures the rigid spacer clamps were uninstalled. This action drastically reduced vibration in the line so that life estimates increased for more than 100 years.