Effect of Suspension Clamp Geometry on Transmission Line Fatigue

This paper reports the results of ah experimental program designed to determine the effect of clamp geometry on conductor static and dynamic strain levels in the vicinity of the clamp and to assess the effect of clamp geometry on conductor fatigue performance. This was accomplished by manufacturing four generic suspension clamp assemblies to support Drake ACSR (795 kcmil) conductor specimens during static and dynamic testing. For each clamp geometry tested, the conductor was instrumented with strain gages to determine strain levels in the conductor strands. Static tests consisted of varying the conductor parameters with three sag angles and three tension levels at each sag angle for each clamp geometry. Dynamic tests consisted of forced vibration tests for each clamp geometry for a single set of line parameters. The investigation showed that both the static and dynamic strain levels increased significantly with decreasing clamp radius of curvature, whereby the most adverse strain level was reached with a 15.2‐cm (6‐in.) radius clamp. As expected, based on the static and dynamic strain data, the fatigue performance of the conductor decreased with decreasing clamp radius. The fatigue performance exhibited by the conductor supported in a 15.2‐cm (6‐in.) radius clamp was inferior to those supported in longer radius clamps.