Fault Investigation and Analysis of an Overhead Transmission Line Vibration Damper

This paper presents the findings from an investigation into the probable cause of damage to vibration dampers found on an existing 110 kV overhead transmission line in the midlands of Ireland. The vibration dampers were positioned on an earthwire and they were found damaged at twelve separate spans along the overhead line. The purpose of this investigation was to establish the main factors which may cause the messenger cable of the vibration damper to deform based on knowledge gained on the characteristics of the overhead line in question, literature review, inspection of the removed dampers and line, and computational analysis. The fatigue characteristics of overhead line conductors, the influence of conductor sag-tension characteristics and conductor wind-induced motions were all factors that have been considered.A fault investigation was designed in two parts. The first part performed by the Electricity Supply Board (ESB) in Ireland, involved modelling the existing line and measuring the vibration response of the line. Part two, conducted by Dublin City University (DCU) involved performing computational modelling to determine the serviceability of the damaged dampers and to validate the findings of the initial fault investigation.