S-1 HM™ Glass Fibers Used in Core of Composite Reinforced Aluminum Conductor Helps Increase Transmission Capacity by Up to 100%

March 27th, 2012 by

AIKEN, SC USA – (March 27, 2012) – When AmpStar, a leader in composite reinforced
aluminum conductors for high voltage transmission lines, wanted to produce a high-heat, low-sag
alternative to conventional transmission cables, it chose S-1 HM™ glass fibers from AGY for the
high-strength composite core of its new composite reinforced aluminum conductor (CRAC*). The
innovative design is a cost-effective solution for improving transmission capacity, lowering line
losses, limiting sag, and reducing the need for more transmission line infrastructure.

According to Mike Winterhalter, President at AmpStar, “The high strength composite core
allows for higher aluminum compaction and the use of higher conductive annealed aluminum, which
increases ampacity by up to 100%. 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 S-1 HM glass fibers used in the composite core are a new glass formulation offering the
highest tensile modulus glass fibers available – measuring 90 GPa (13,053 ksi). “The S-1 HM glass
fibers were developed as a next generation of S-Glass products,” said Drew Walker, President of
AGY. “The proprietary glass formulation, available as a roving package, is designed to maximize
performance properties while meeting the economic needs of the reinforcement market.”

AmpStar developed this latest version of CRAC in response to challenges from utilities’- and
stranders’- 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,” explained 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 said, “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.”

In addition to toughness and high-heat performance, the CRAC also has the ability to
mitigate line loss. “All conductors have some line loss,” explained Winterhalter. “However, using
a composite core can reduce the loss by as much as 30%. This increased efficiency can result in
reduced carbon footprints for the power generator and a cost savings in fuel.”
As the demand for power continues to increase, re-conductoring is a more efficient way to
improve transmission capacity. “It is not possible to simply add transmission corridors to increase
delivery due to the cost, and to the many environmental hurdles,” explained Winterhalter. “So, the
alternative is to re-conductor with high capacity/more efficient conductors capable of delivering
more electricity on the same towers with essentially the same hardware. New lines are also being
designed with an eye for efficiency. Since our conductor is stronger, the spacing and size of towers
and the purchase of rights-of-way become less costly. This is a major cost advantage.”