The NWT Power Corporation issued a statement setting out some basics about why Yellowknife lost power for two extended periods on Wednesday – but the root cause remains a mystery.
The territorial capital has faced multiple outages over recent weeks.
The latest major blackout, on Wednesday evening, lasted for just under an hour. Another hour-long outage happened in the early hours of the same day.
Two entities are involved in providing electricity to Yellowknife customers. The GNWT-owned power corporation, also known as NTPC, generates the city’s power, then private operator Naka Power NWT distributes it to homes.
On Thursday afternoon, NTPC said both Wednesday outages were caused by “line trips” – safety valves, in effect, that kick in when a part of the system is operating outside safe operating limits in a bid to stop things getting worse.
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Line trips can occur for various reasons. Often, the source of the trip will be traced back to a short circuit caused by lightning, animals like ravens, or trees on the line. Equipment failure and other issues can also cause a similar trip.
Right now, NTPC does not know why Wednesday’s line trips occurred. Attempts to investigate by helicopter couldn’t happen as the weather that day was too poor.
“A line patrol is planned for later today, weather permitting,” the power corporation wrote at 3pm on Thursday.
“Additional trades staff have also been deployed to Snare to assist in stabilizing Yellowknife’s power supply,” NTPC’s statement added, referring to the hydro network serving the city. The line trip is believed to have occurred near the Snare Cascades facility that forms part of the network.
“Additional information will be shared once we learn more about why the line trips occurred.”
NTPC said both the power corp and Naka Power NWT “appreciate how frustrating this is for customers and continue to work closely together to ensure that power is restored as quickly as possible following an outage and that the public is kept informed about what is happening and why.”
