Tight buffered fiber optic groundwire cable

Abstract

A fiber optic groundwire or static cable for use between spaced-apart support towers of an electrical power transmission network, for ground fault protection from lightning strikes and other electrical faults, with an integral fiber optic telecommunications bundle. A bundle of optical fibers tightly enclosed by a pliable thermally insulating strain jacket is firmly affixed into a helically-wound channel within an electrically conductive core. At least one layer of stranded electrical conductors serving as strength members completely surrounds the core. The tight jacketing of the optical fibers by a pliable strain jacket, combined with the firm mounting of the strain jacket within the helical channel of the core, reduces the axial tensional forces on the optical fibers that occur during and after installation of the cable. Also, the cable provides improved fault current carrying capability by utilizing a strain jacket made from a high temperature and thermally insulating silicone-based or ethylene propylene-based material. In another embodiment, the wire includes at least one fiber optic subunit firmly affixed into a helically-wound channel within an electrically conductive core of the cable. The fiber optic subunit comprises a plurality of optical fibers wound about a fiberglass central strength member having an overcoating layer of a pliable semicompressible material, and tightly enclosed by a pliable thermally insulating strain jacket.