Conductor fatigue life research

This is the final report of Phase 4 of Research Project RP 1278-1 sponsored by the Electric Power Research Institute and carried out at the Civil Engineering Department of Auburn University and United Power Association (UPA) in Elk River, Minnesota. The primary objectives of this Phase 4 work were to: monitor transmission line vibration and site wind activities at various sites to evaluate the effects of terrain, windfield and season of the year on line load''-N curves, and to evaluate correlations between line vibration and site wind activities; experimentally evaluate appropriate S-N curve modification factors for different transmission line conductor types, line conditions and clamp conditions; investigate and develop an improved dynamic bending stress equation for predicting aeolian fatigue stresses in the strands of multistranded overhead conductors; experimentally refine the level of amplitude reduction required to arrest significant further fatigue damage to conductors that are already minimally damaged; and study and evaluate interactions between wind, conductor vibrations, support hardware vibrations and support tower vibrations for a 2-conductor bundle transmission line located at a very active wind site.