Development of flexible joint for 500 kV Al-sheathed OF cable

The authors have developed a flexible dimensionally flush joint for 500 kV aluminum-sheathed oil-filled cables with handling characteristics similar to the cable itself so that it may be readily drawn into ducts in the same way as the cable without suffering damage. The process and characteristics are outlined. This joint is intended for use at intermediate points on long bridges or tunnels where local assembly and installation of conventional joints would be difficult. In developing the joint, various novel techniques have been used, including the flexible flush jointing of segmental conductors, the flexible jointing of paper insulation by a combination of wrapping-back and stepping methods, and on-site aluminum sheath corrugating and sealing methods