The provincial crown corporation said in a statement Monday that its monitoring system first detected a bulge and oil leak on July 8 in an undersea cable that runs underwater off the Sunshine Coast. to the island. After this initial discovery, two more cables were discovered over the weekend that are also bulging. BC Hydro said the leaking cable was taken out of service and the leak, which consisted of non-toxic mineral oil, was contained. The load on the other two cables has been reduced and they are closely monitored.
The affected cables run from the Sunshine Coast, over Texada Island, then travel underwater to Nile Creek, near Qualicum Bay on Vancouver Island, where they connect above ground with the Dunsmuir substation which then sends electricity up and down the island.
The cables, which are made in Norway, are each 15.24 centimeters in diameter. Inside is mineral oil which acts as a coolant surrounded by a copper pipe which conducts electricity. The copper pipe is coated with lead, which is covered with plastic and the entire cable is then sheathed with concrete.
Ted Olynyk, BC Hydro’s director of community relations for Vancouver Island and the Sunshine Coast, told CBC News Tuesday morning that the cable leak occurred over water near a terminal on Texada Island, so that repairs on this cable can be made above ground.
He said repairing cables is a complicated job, but islanders shouldn’t worry about losing electricity.
“We have enough to meet our load,” said Olynyk, who he says is around 1,000 megawatts at this time of year.
He said the island still receives enough power from another set of cables running from Tsawwassen to Duncan, can generate its own power on the island, and can rely on independent power generators on the island for fill gaps.
However, as a precautionary measure, BC Hydro has told its largest industrial customers on the island that they may need to reduce their electricity use.
“We’re just warning that it could happen,” Olynyk said.
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While an investigation is underway to determine the cause of the damage, Olynyk said the cables were inspected in May and again in mid-June just before the recent heat wave hit British Columbia.
During the last inspection, Olynyk said there were no “anomalies” observed on the cables.
Temperatures in late June broke previous heat records this year – with mercury reaching 40C in Vancouver and considerably higher in the interior.
“I think it points in that direction [the heat wave] at this point, ”Olynyk said, adding that he had concerns for the future of the infrastructure if such heat episodes became more frequent.
According to Olynyk, about 70 percent of the island’s electricity is supplied by cables coming from the mainland.
British Columbia’s high-voltage transmission system consists of more than 18,000 kilometers of submarine lines and cables. Seventy to 80 percent of the province’s electricity is consumed in the Lower Mainland and on Vancouver Island.
Electricity is supplied to the Lower Mainland and Vancouver Island from the Peace River hydroelectric system through the Kelly Lake substation, and from the Columbia River system through the Nicola substation.