Analysis of factors contributing to conductor failures on a 345 kV line

A 2156 ACSR phase conductor on 345 KV line W5 between South Fond du Lac and Columbia substations failed in 1994. Several vibration dampers were noticed to be damaged or missing from the 20-year-old line during subsequent maintenance inspections. A limited vibration analysis identified the cause of the failure to be galloping. Recommendations were made to install additional Aeolian vibration dampers and to add antigalloping devices to reduce the galloping. A second phase conductor, also the top phase, failed during December of 2000. That line section was in the next set to have new dampers installed and had been noted to have Aeolian vibration dampers missing. Several methods of analysis, some physical, some graphical, some analytical were used to try to determine the cause of the galloping and the extent of any cumulative damage. This paper will detail the steps taken, the conclusions reached, and the corrections implemented.