wiredInUSA September 2020

Pipe-type retrofit M A K I N G T H E NEWS

Sumitomo Electric Industries and its subsidiary, Sumitomo Electric USA, have completed a pipe-type cable to XLPE cable system retrofit replacement in San Francisco. The San Bruno Interchange project, developed by Pacific Gas and Electric Company (PG&E), included the replacement of one existing pipe-type cable system (high pressure gas-filled) with a new solid dielectric cable system, maximizing the reutilization of existing infrastructure, andmaintaining thecurrent transmission capacity of the circuit. New AC 115kV cross-linked polyethylene (XLPE) insulated underground power cables were installed into an existing 8˝ steel pipe, to feed into the existing substationsbetweenSanBrunoandSouth San Francisco. The circuit route between the two substations is approximately 1,200 feet (365m) in length. The power

cables were replaced while keeping the existing 8˝ steel pipes intact.

The project included the installation of air-blown fiber optic cable, distributed temperature sensing (DTS) system and related equipment, jointing and terminating work, field testing and commissioning testing. Sumitomo Electric designed, supplied and installed its high voltage XLPE triplex cable, consisting of three stranded single-core XLPE-insulated cables for high current capacity, with the largest conductor of 2,500kcmil. The design mitigates the thermal-mechanical behavior inherent to power cables, while reducing the workload and space required for installation compared with single-core cables.

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wiredInUSA September 2020