Suspension Clamp and ACSR Electrical Conductor Contact Conditions

Abstract

A one-dimensional model is presented for the analysis of contact between a typical suspension clamp and an overhead electrical conductor. Besides span parameters (sag angle, static tensile load), conductor curvature at the last point of contact is shown to depend on clamp profile. Strain measurements are performed on the bottom free surface of a typical commercially available suspension clamp, and of a simpler, yet similar, generic clamp, with a Bersimis ACSR conductor specimen. Various sag angle and tensile load combinations are imposed. Using an inverse method, measurements made on the generic clamp allow, through finite-element method modeling, the calculation of an approximate contact load distribution between clamp and conductor. With the usual assumption of minimum conductor bending stiffness, good agreement is found between experimental and theoretical results. Most notably, an experimentally observed tensile strain zone at the clamp bottom surface is shown to correlate well, both qualitatively and quantitatively, with a calculated localized contact region. Such tensile zone could be used to study contact conditions in other clamp-conductor systems.