BC Transmission Corporation (BCTC), the transmission system operator for the province of British Columbia, will install 3M’s lightweight, high-capacity electricity conductor, 3M Aluminum Conductor Composite Reinforced (ACCR). ACCR can carry twice the current of conventional steel-core conductors of the same diameter, without requiring larger towers, even across long spans.
BCTC will deploy ACCR in two cross-water segments through islands in the Straight of Georgia as part of an upgrade for a transmission line linking Vancouver Island with British Columbia’s lower mainland. The upgrade is known as the Vancouver Island Transmission Reinforcement (VITR) Project.
The 3M ACCR segments, which include a 5,800-foot (1,770-meter) single-span crossing the Sansum Channel between Vancouver Island and Salt Spring Island, in addition to a 6,000-foot (1,830-meter) multi-span crossing, are located about 25 miles north of Victoria, the provincial capital. The installation is currently in progress and scheduled to be completed in June 2008.
According to Tim Koenig, director of the 3M High Capacity Conductor Program, 3M ACCR was chosen, in part, to permit the re-use of existing towers, and avoid potential environmental sensitivities and costs associated with building larger towers for the conventional ACSR conductors.
“Larger towers to accommodate double bundling, for example, would have required bringing heavy equipment into remote areas, some by barge, installing new foundations and guide wires, installing new towers, digging out the existing footings and then transporting the aggregate for an additional 24 towers,” says Koenig. “Moreover, one of the segments goes through part of a provincial park. The existing sightline and minimizing installation requirements are definitely pluses.”