December 23, 2022

Prior To Major Event

1. Did the distributor have any prior warning that the Major Event would occur?

Yes, Environment Canada issued a Special Weather Statement on December 19th, 2022 at approximately 16:00, a Winter Storm Watch on December 21, 2022 at approximately 15:00 and a Winter Storm Warning on December 22nd, 2022 at approximately 15:00.

2. If the distributor did have prior warning, did the distributor arrange to have extra employees on duty or on standby prior to the Major Event beginning? Brief description of arrangements, or explain why extra employees were not arranged.

Once Environment Canada issued the Winter Warning Watch, all Hydro Ottawa Operations employees were contacted for availability. All available Line staff and underground staff were instructed to report into their work location on December 23rd, 2022 at 6:00. All On-Call staff were instructed to report in on December 22nd, 2022 at 18:00 in preparation for the event as well as the Incident Command Centre was stood up at the same time.

3. If the distributor did have prior warning, did the distributor issue any media announcements to the public warning of possible outages resulting from the pending Major event?

Yes, Hydro Ottawa published media announcements across social channels warning of possible outages resulting from the pending Major event.

4. Did the distributor train its staff on the response plans for a Major Event? 

Yes. Hydro Ottawa has an established Electrical Emergency Response Plan and Organization, which includes processes and procedures for which staff are trained on.  Formal training is completed annually according to Market Rules.  In addition weekly preparation meetings are held to refresh on-call management personnel.

During the Major Event

1. Please identify the main contributing Cause of the Major Event as per the table in section of the Electricity Reporting and Record Keeping Requirements.

  • Loss of Supply
  • Lightning
  • Adverse Weather - Wind
  • Adverse Weather - Snow
  • Adverse Weather - Freezing Rain/Ice Storm
  • Adverse Environment - Fire
  • Adverse Environment - Flooding
  • Others

1.1. Please provide a brief description of the event (i.e. what happened?). 

On December 23rd at 1:01AM, Hydro One S7M circuit and Cambrian's T1 transfer tripped which resulting in a loss of supply to four Hydro Ottawa substations which led to 31,897 Hydro Ottawa customer outages.

2. Was the IEEE Standard 1366 used to identify the scope of the Major Event? If not, why not?

Yes. Hydro Ottawa used the IEEE Standard 1366.

3. When did the Major Event begin (date and time)?

December 23, 2022 at 1:01AM

4. Did the distributor issue any information about this Major Event, such as estimated times of restoration, to the public during the Major Event? If yes, please provide a brief description of the information. If no, please explain.

Yes, estimated times of restoration were provided on the Hydro Ottawa website Outage Map, Power Outage Line and by email Outage Alerts prior to it going into Storm Mode. Estimated times of restoration were also provided through responding to requests from media, shareholder and social media.

5. How many customers were interrupted during the Major Event? What percentage of the distributor’s total customer base did the interrupted customers represent?

67,710 customers were interrupted during the Major Event, representing 19% of Hydro Ottawa’s total customer base.

6. How many hours did it take to restore 90% of the customers who were interrupted?

It took 12 hours and 30 minutes to restore 90% of the customers related to the major outage.

7. Were there any outages associated with Loss of Supply during the Major Event? If so, please report on the duration and frequency of Loss of Supply outages.

Yes, there was one Loss of Supply during the Major Event resulting from a cable fault on the transmission supply. The outage affected 36,147 customers for a total of 38,667 customer hours. The outage contributed 0.100 to SAIFI and 0.107 to SAIDI.

8. In responding to the Major Event, did the distributor utilize assistance through a third party mutual assistance agreement with other utilities? If yes, please provide the name of the utilities who provided the assistance?


9. Did the distributor run out of any needed equipment or materials during the Major Event? If so, please describe the shortages.


After the Major Event

1. What steps, if any, are being taken to be prepared for or mitigate such Major Events in the future (i.e., staff training, process improvements, system upgrades)?

  • No further action is required at this time.
  • Additional staff training
  • Process improvements
  • System upgrades
  • Others

Additional comments:

A debrief is being conducted and findings will be actioned to ensure Hydro Ottawa continues to be prepared for such events.

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