Regarding the power outages the week of June 18, 2023

Jun 27, 2023  Comment

We know that no one likes power outages, and we recognize there have been several over the last week. We apologize for this and any inconvenience the outages may have caused. We take each outage seriously and do our best to restore power as quickly as possible in these situations.

In the summer, we rely primarily on hydro to provide our electricity. So, when our hydro units trip we lose a significant source of generation. This was the cause of the outages on June 18, 19, 20 and 21. One of our hydro units tripped and we lost nearly half of the electricity we generate in the summer. Operating a power grid always requires a balance between generation and load. So, losing a large hydro unit resulted in an imbalance, with the load significantly larger than what the available generation could handle. When this happens, the grid will protect itself by shedding excess load to quickly restore balance between load and available generation, keep the system stable, avoid total grid outage, and ensure quick restoration.

After further investigation into why the hydro unit tripped, we found that it was caused by a point of weakness in the protection and control systems’ wiring. There are thousands of wires in the power grid, so it is not possible to check all of the wires regularly. In other words, there was no way of knowing this would happen, until it did.

The manufacturer of these systems has since rewired the faulty part of the control system to prevent this from happening again.

The outages on June 22 and 23 were caused by lightning. Unfortunately, there is little we can do to prevent outages such as these.

During these outages, we used diesel and LNG to make up for the lost generation and to restore power quickly. Despite the hydro unit being offline for days, the average outage length was one hour and 12 minutes. We used diesel as this is the fastest and most economical way to restore power. There are also diesel facilities in Dawson, Faro, Mayo and Whitehorse which we used to restore power to these communities before tying the grid back together.

We thank everyone for their understanding and apologize again for the disruptions these outages may have caused.


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