Broken transformer caused Yellowknife power chaos, NTPC says

A malfunctioning transformer at Yellowknife’s Jackfish diesel plant contributed to Sunday’s unprecedented succession of power outages, the NWT Power Corporation says.

Trees on the line from the Snare hydro system were the initial cause of outages on Saturday and Sunday, but the Jackfish diesel system did not kick in as expected to deliver backup power.

In an update provided to Cabin Radio, the power corporation said Yellowknife endured rolling blackouts on Sunday afternoon because staff “ran into problems with maintaining voltage stability on the system.”


“Workers identified that a transformer at Jackfish was responsible for the stability issues,” spokesperson Doug Prendergast said by email, adding that transformer was taken offline, after which a combination of diesel and hydro was used to finally restore full power.

In a separate press release on Tuesday, the power corporation stated: “NTPC is conducting an inspection of the transformer to determine why it was not functioning properly on September 11.

“NTPC will make necessary repairs to the transformer before it is returned to service.”

The power corporation’s president, Cory Strang, said NTPC had not met its own expectations and must do better, despite praise in some quarters for workers who spent their Sunday working to fix the problem.

A series of six outages in 24 hours comprehensively pickled at least one resident’s fridge-freezer and blew a projector and ice machine at Yellowknife’s theatre, among damage reported to Cabin Radio. It’s possible that other damage to electrical equipment in the region has gone unreported.


The Capitol Theatre said on Monday it had repaired its projector. The movie Brotherhood, showings of which were abandoned during Sunday’s outages, will now have extra screenings at 4:15pm on Saturday and Sunday this coming weekend.

In statements on Monday and Tuesday, the power corporation acknowledged the role high winds had played in disrupting power to both Yellowknife and Behchokǫ̀.

In Behchokǫ̀, a separate generator issue – a diesel unit failed to start remotely – led to an unrelated delay in restoring power. The power corporation said a contractor had to spend an extra 20 minutes getting to the unit and starting it.

“NTPC recognizes that multiple outages in Yellowknife, Dettah and Behchokǫ̀ this past weekend were inconvenient and stressful for electricity users,” Prendergast stated by email.


“Additional investigation will continue until [there is] a complete understanding of what happened and what steps need to be taken to resolve all of the issues identified.”

Prendergast said removal of trees dangerously close to the Snare transmission line had already been scheduled for late September and early October.

“The trees that came into contact with the transmission line this weekend would likely have been removed during that process,” he wrote.

Strang, in a statement, added: “NTPC is committed to providing reliable electricity service to its customers and other electricity consumers.

“We clearly did not meet our own expectations this weekend and understand the frustration that has been expressed about the extended outages. We must do better in the future.”