A Maritime Electric worker repairs a line in this Guardian file photo
An emergency system was activated Thursday, cutting electrical power to parts of P.E.I. to prevent a total blackout across the province.
Maritime Electric issued an advisory at 5:40 p.m. saying that about 5 p.m. Thursday it cut power to certain large business customers, a process it called shedding load.
“We have a handful of large customers on P.E.I. that are called interruptible business customers,” said Kim Griffin, spokesperson for Maritime Electric. “They get a reduction on the cost of their power because if situations like this occur, we have the right to cut off their power.”
While that was happening, another problem with the electrical system arose, the exact cause of which was not determined as of Thursday night.
“As the system started to shed load and cut off these interruptible business customers, we also had some freezing problems,” said Griffin. “The system began to shut off more customers to protect itself. It all happened within 30 minutes of each other.”
It created power outages from Hunter River to Sherbrooke including Kensington, New Annan, Hunter River, Rattenbury and surrounding areas.
“The system started to restore power within 15 minutes,” said Griffin. “We went in and very slowly and systematically restored all our residential customers first.”
By 7 p.m. all residential customers had power back on and businesses costumers were slowly returning to full power.
Griffin said Maritime Electric would have preferred to issue warnings to the Island but the usual surge of power demand between 5 and 7 p.m. was much higher than expected Thursday.
“This happened very quickly,” she said. “With the cold temperatures, people were using more power than ever.”
Much of that increased demand is likely due to the popularity of residential air-source heat pumps or other sources of electrical heat.
“We have been talking about that for the last several months,” said Griffin. “If consumers can, where possible, if there are areas where they can conserve, that certainly helps.”
It was not a rolling blackout or brownout, she said of Thursday’s event.
“This was an emergency power outage,” said Griffin. “We had to protect our cables. If this didn’t happen, you could have a blackout.”
Griffin said the computer system’s analysis of the entire Island balances the electrical load across zones and determines which areas will have power cut first, and subsequently in which Island zones.
“It is a computer-controlled system that affects all of P.E.I.” said Griffin. “It is called the Cable Overload Scheme, and it actually worked exactly how it’s supposed to work because it has to protect our whole system and all of our cables. It performed as it should.”