AGY S-1 HM glass fibre used in AmpStar composite reinforced aluminium conductor

AmpStar, a producer of composite reinforced aluminium conductors for high voltage transmission lines, has chosen S-1 HM™ glass fibre from AGY for the high-strength composite core of its new composite reinforced aluminium conductor (CRAC).

The CRAC design is a cost-effective solution for improving transmission capacity, lowering line losses, limiting sag, and reducing the need for more transmission line infrastructure.

High strength core

 “The high strength composite core allows for higher aluminium compaction and the use of higher conductive annealed aluminum, which increases ampacity by up to 100%," says Mike Winterhalter, President of Ampstar.

"When compared to other composite core/conductors, including those using a hybrid carbon and glass composite, the AmpStar CRAC offers equal or better mechanical properties, higher Tg and a much reduced cost over the competition.”

The

AmpStar developed this latest version of CRAC in response to challenges from utilities to increase properties, particularly tensile properties, but keep the same beneficial pricing. The resulting design combines the properties of the S-1 HM glass and a high-temperature reactive matrix.

“The S-1 HM material is the reinforcement that meets our higher performance specifications,” explains Winterhalter.

“It has excellent tensile and modulus properties. We combine the reinforcement with a proprietary resin package that affords higher temperature operation of the core/conductor, allows for increased throughput, and has a synergistic effect with the reinforcement package. Designing a composite part, especially a tensile member, necessitates that the properties of the reinforcement and the resin system work together. This is true not just for the material properties, but for the chemical compatibility of the two as well.”

Explaining the importance of tensile strength and high-heat performance in the CRAC design, Winterhalter says: “Toughness is especially important as it directly speaks to the rod’s ability to accept hardware such as splices, and dead-ends, and how it can handle bend radius extremes. High-heat performance is essential for overhead conductors because the transmission of electricity inherently builds heat. The higher the current, the higher the heat. In contingency operations, the conductor cannot fail due to developed heat.”