What happened yesterday to cause an all-day outage in Moncton and Riverview?

January 21 2018, 15:26 PM

 Early morning yesterday a large number of customers in the Moncton and Riverview areas were impacted by a transmission outage. Many customers have asked us why this outage happened and why did it take so long to restore power.

Restoration work requires a sequence of events that must take place in a specific order before the next task can occur. Many things can affect the timing of the sequence, like access to location, needing specialized equipment etc.

In yesterday’s case, an equipment fault happened in a remote location at an intersection of two transmission lines feeding three separate substations. Transmission lines feed the distribution substations that feed the distribution lines which in turn, feed into homes and businesses.

A transmission outage – like we saw on Saturday – is more difficult to address and results in larger outages. Crews were dispatched but given the remote location of the fault, more time was needed to get to the site, find the fault, bring in specialized equipment like off-road machinery, excavator, crane etc.

The initial plan was to make necessary repairs at the source of the issue, so crews outlined a plan to make the repairs, obtained work permits, brought in the heavy machinery and resources. Unfortunately, crews ran into some difficulty executing the original plan and decided to manually reconfigure the transmission circuit, isolating the damaged portion and try and energize the transmission line from another source. Once this work was done on the transmission lines, crews then needed to focus on restoring the impacted substations.

Transmission lines need to be energized before the distribution lines can be re-energized. While crews were working on the transmission lines, other crews were working to get the distribution lines ready to pick up the load once re-energized.

During this time our website displayed incorrect information regarding customers’ estimated restoration times and total number of customers impacted by the outage. We apologise for this. In cold winter months, when the power has been out for a long period of time, we can experience what is called “cold load pickup” meaning the grid is overloaded when it’s restored, and by design in order to protect itself from damage, will go out again. Some of our customers may have experienced one of these “cold load pickup” outages yesterday. Most customers were restored by 9 pm last evening.

As you can see, power restoration is not a simple task but we can assure you our crews were working as fast as possible to rectify the situation and we absolutely understand this was not an easy situation for customers, especially in winter months. We thank you for your patience.