Performance Aspects of a Novel Two-Rod, Dielectric Sheath Design for Central Tube Cables

摘要

Designs for dielectric cables include strength members comprised of multiple packages of glass and/or synthetic fibers, coupled together with varying amounts of crosslinked resin. These composite reinforcements cannot rival the mechanical properties per unit area nor the cost per unit length of their metallic counterparts. For these reasons, fabrication of dielectric cables that are cost-effective, compact, and sufficiently robust is a challenge for the cable designer. This paper discusses the design and performance of a new central tube, dielectric cable sheath that employs two linearly applied composite rods. The new sheath design has been applied to a wide variety of core structures, including, tube-in-tube, filled ribbon and dry ribbon cores. The composite rods utilize novel coatings that provide optimized coupling between the rods and the cable jacket. This coupling is quantified through laboratory measurements of adhesion between rods and the cable jacket. Adhesion results are also compared with adhesion performance of rods that use other types of coatings. Optimized coupling between the rods and the outer jacket results in excellent behavior in tensile, compressive and twisting deformations, as illustrated by cable-level mechanical tests. Most importantly, the new sheath design provides substantial improvements in installation performance. We report the results of a rigorous series of installation simulation tests, comparing results for this sheath design to alternate dielectric sheath designs.