/images/buttons/TDU_thumbnail.GIF/images/southwire_100x70.jpgLaminate-Tape Sheaths Squeeze HV Cable Size and Costlaminate-tape-sheaths-squeeze-hv-cable-size-and-cost.htmUnderground high voltage (HV) installations can benefit from cable sheaths made of metallic laminate tapes.
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Laminate-Tape Sheaths Squeeze HV Cable Size and Cost

Underground high voltage (HV) installations can benefit from cable sheaths made of metallic laminate tapes.

Specifiers of underground high-voltage systems should know about Southwire's diameter-reducing, cost-squeezing options for extruded XLPE dielectric HV (69 - 230kV) cables.

"Replacing corrugated cable sheaths with copper or aluminum laminate tapes in HV cable designs delivers useful reductions in both overall diameter and cost," says Lucian Munteanu, HV project engineer for Southwire's Energy Division.

In laminate-sheathed HV cables, copper sheathing tapes are typically 6 mils thick, and aluminum tapes are typically 8 mils thick. An outer copolymer layer on the laminate tape bonds the tape to the outer jacket during the extrusion process, creating an excellent barrier to water penetration. Semi-conducting, water blocking tapes on either side of the concentric neutrals provide even more water protection.

Laminate sheaths can help reduce overall project costs

Because of their reduced diameter, extruded dielectric HV cables with laminate sheaths make good replacements for paper-insulated HV cables in oil-filled pipe installations. In a recent 69kV application, three 2,250 kcmil conductors replaced deteriorating oil-impregnated paper-insulated conductors in the original 8-inch pipe. The laminate-sheathed XLPE cables provide equal or greater ampacity without the cost of new duct banks or conduits.

Laminate-sheathed HV cables are also lighter and more flexible than cables with corrugated sheaths. The smaller diameter and lighter weight of laminate-sheathed cables allows more cable on a reel. That reduces the number of manholes needed for specific projects, which reduces overall costs.

Choose from stranding options in large conductors

"In addition to standard compressed round stranding, Southwire can provide extruded-dielectric HV cables with segmental conductors that reduce skin effect in sizes up to 4,000 kcmil," Munteanu says. "And Southwire manufacturing has 5,000 kcmil segmental conductors in development."