Outages Analysis

July 3, 2024

NOTL Hydro has had a number of outages over the past three months and this has prompted a number of complaints from our customers.  We understand their frustration.  So much relies on electricity these days (internet, Point of Sale systems, air conditioning) that its loss is readily apparent and affects regular activities.

NOTL Hydro tracks all outages carefully including the length of the outage, the number of customers affected and the cause of the outage when it can be identified.  This chart, which measures the frequency of outages per customer on an annualized basis, shows the increase in outages in April and May.  June has only just ended but we know its outage stats will be high as well.  This recent spate of outages follows a period of 3 months (Jan-March) in which there were very few outages.  People, understandably, remember when their lives have been impacted by outages and not when there were few or no outages.  This chart is part of a detailed analysis provided to the NOTL Hydro Board on a monthly basis.

Chart showing monthly SAIFI values for 2024.

NOTL Hydro manages its system and invests where it can to try to minimize the impact of outages.  This is a key objective.  This chart measures NOTL Hydro against all the other electrical utilities in Ontario except Hydro One.  Hydro One is excluded as their service area includes most of rural Ontario which is not a fair comparison.  Including Hydro One would make NOTL Hydro look even better.

Chart showing Average Outage Frequency Index.

NOTL Hydro recently analyzed its outages over the past nine years to determine if there were any patterns that required attention or might indicate an opportunity for improvement.  The first thing we looked at was the timing of outages throughout the year.  Was there any seasonality that we should build into our planning?  The general answer is that outages can occur throughout the year and that there was no consistent peak time.  Looking at the nine-year average, the thicker gold line, there are more outages in the summer but not by a considerable amount.  This is likely due to tree growth and increased animal activity at this time of year.

SAIFI by month from 2015 to 2023.

The next thing we looked at is the cause of the outages and whether there were some unexpected patterns.  There are nine types of outages tracked.  These are defined by the Ontario Energy Board so that they can be compared across electricity utilities in Ontario.  How cause is attributed to an outage can be subjective so may not be consistent over time based on personnel.  We looked at causation both on a per customer basis, which accounts for how many customers are affected, and on a per incident basis.

Outage Causes by Customer Impact
Outage Cause by Incident
CauseCustomers ImpactedNumber of IncidentsComments
Loss of supply20,6644Loss of power from Hydro One.  Happens rarely but will result in half or all of NOTL losing power.  
Adverse weather16,39040Ice, freezing rains or high winds can all cause outages and these outages can be widespread.  
Defective equipment13,601111Pole fires, leaking transformers, failing sleeves are all examples.  Equipment can fail due to age, wear, weather conditions and other stresses.  
Unknown12,86559There are outages as evidenced by a blown fuse or other indicator but the reason for the outage is not evident.  This may often by due to animal contact where the evidence is no longer onsite.  
Tree contacts10,57183Falling trees or branches that hit power lines and stay in contact with the lines cause outages that can vary in size based on where the contact occurs.  If contact is not maintained then power will normally be immediately restored due to reclosures which reset the power.  
Lightning7,10525Lightning destroys equipment due to its immense power.  How widespread the resulting outage is will depend on the location of the strike.  
Scheduled4,316119The most common form of outage but the lease impactful.  Customers are given advance warning, the duration is usually relatively short and only a small number of customers are affected each time; usually less than 20.  
Foreign Interference3,25198Contact by animals or by human activities (driving into a pole).  These are common but their impact is usually limited to a smaller number of customers.  
Human Element2,4817These are outages caused by the activities of NOTL Hydro that are not planned.  These are limited.  The last one was in 2021.   

Leave a Reply

Your email address will not be published. Required fields are marked *