Maritime Link problem causes power outage in parts of Newfoundland
N.L. Hydro still investigating what it calls 'significant event on the system'
Newfoundland and Labrador Hydro says a malfunction with the Maritime Link led to a swath of power outages across Newfoundland Monday morning.
Rob Collett, N.L. Hydro's vice-president of engineering and the N.L. system operator, said the problem — which the company referred to as a "significant event" — caused power to be exported from Newfoundland to Nova Scotia much faster than usual, leading to an imbalance in the system.
"It's like a bunch of people carrying a couch. You know, we try to keep things in balance, but if someone suddenly lets go or the couch suddenly gets heavier…it can cause a disturbance and everyone has to re-balance things," Collett said.
Collett called it an "under-frequency load shedding event."
According to the company's website that's when generation drops — the result of a problem with a generating unit, for example, or with the electricity system itself, and "predetermined blocks of customers are automatically dropped to protect the system from going into a widespread blackout. In other words, we turn off the power in certain areas if we suddenly lose a large chunk of generation."
"So that's unfortunately what happened, is that we had to shed about 57,000 customers," said Collett.
The company said most of them had power restored within 16 minutes.
N.L. Hydro hasn't identified the cause of the malfunction, but Collett said Hydro is working figure out why it happened.
He called Monday's outage an isolated incident.
The Maritime Link transmits hydroelectric power from Cape Ray to Point Aconi in Cape Breton over 180 kilometres of subsea cables. The $1.52-billion link is part of the Muskrat Falls project.
Electricity was first transmitted over the link in 2017. It was the first time Newfoundland had been connected to the North American energy grid.
Collett said N.L. Hydro is working with colleagues at Newfoundland Power and in Nova Scotia to ensure the system stays reliable heading into the winter months, but said it's also important to keep "learning from the missteps that have happened."
"We do have a ways to go, but the Labrador-Island Link is coming together," he said. "We have reason to be optimistic that our system reliability will continue to improve. And we'll work through it with our colleagues to ensure a reliable system."
With files from Carolyn Stokes