Outages Blog

July 13, 2022

There are basically three things our customers want from NOTL Hydro: a fair bill, no outages and good service when needed. We know our bills are fair as we have some of the lowest rates in Ontario for the parts of the bill that we control. We are also pretty confident that our service is good though we know it can always be improved. The reality is we can never promise zero outages. There are too many events that can create a power interruption. What we can do is to try to make them as infrequent and as short as possible.

­­There are two standard indices used in the industry that measure outage performance. The first is the System Average Interruption Duration Index (SAIDI) which measures, on average, how long NOTL Hydro customers are without power over the course of a year. NOTL Hydro is typically a little under an hour which is close to but slightly below the Ontario average. The second is the System Average Interruption Frequency Index (SAIFI) which measures, on average, how often NOTL Hydro customers are without power over the course of a year. Recently, NOTL Hydro has been averaging less than one average outage per customer which is well below the Ontario industry average. The score jumped to 1.25 interruptions in 2021 due to a couple of widespread outages. For both measures we exclude outages due to loss of supply from the Hydro One transmission grid. These are out of our control. For fairness, we also exclude the Hydro One distribution result as their customer base includes almost all of rural Ontario which increases the likelihood of outages.

The causes of outages are fairly standard.

  • One common cause is a tree contact which causes a short circuit in the system. Windy days can be bad for this; especially if the wind is off Lake Ontario.
  • Animal contact is also common. An owl caused an outage last weekend, for example. An animal on one wire of our system is fine but an outage happens if they make contact with two separate points at the same time. This creates an alternate path for the electricity to flow and does not end well for the animal.
  • Lightning strikes also cause outages.
  • Failing equipment can also be a cause for outage. Our equipment is expected to be good for 40 years or so. However, due to defects in the equipment or high use the equipment can fail.
  • Human interaction can cause an outage. The most common incident of this type is an auto accident that also takes down a hydro pole. All are cautioned when using ladders or other long tools outdoors to be aware of above ground electrical distribution lines. Making contact with overhead lines may result in a power interruption, or worse, for the person using the tool.
  • Fires also cause outages. The fires can be on our equipment itself (pole fires) or unrelated to our system (house or brush fires) but create an outage incidentally as well.
  • Finally, we have to plan for certain outages in order for our crews to work on the system. Fortunately, we are able to make system adjustments so that these affect as few customers as possible.

A number of actions are being taken to try to reduce the number of outages and their impact.

  1. Our ongoing capital programs are designed to replace a certain amount of the system each year. These programs allow NOTL Hydro to replace older parts of the system with new equipment and to upgrade to more modern equipment.
  2. The ongoing project to move some of the system underground in the Old Town also helps reduce outages. Underground systems typically have fewer outages than above ground ones as the infrastructure is not exposed to the effects of adverse weather.
  3. A number of poles have been and are being replaced this year and over the past few years. Around 100 will be replaced in 2022. These are scattered throughout the Town and have been identified as being in bad shape through testing and visual inspection. Newer, stronger poles are less likely to come down.
  4. A contractor for NOTL Hydro trims some of the trees each year to reduce the number of contacts. The full Town is covered every three years. The gap between the hydro wires and foliage is required to be 3 metres, and is sometimes increased beyond that minimum clearance distance to further reduce the number of contacts. In addition, NOTL Hydro is working with the Town to remove some of the dead trees that could fall on the hydro lines.
  5. NOTL hydro is in the process of replacing steel switch and fuse brackets to fibre brackets. These are less likely to cause an outage due to an animal contact. The brackets are being replaced as part of regular capital and maintenance work and not as a special project.
  6. As part of our regular maintenance program, NOTL Hydro is identifying where circuits tap on solid to the main line. Crews are replacing the solid tap with fused cutouts to improve sectionalizing capabilities and reduce the number of customers affected by an outage.
  7. Porcelain insulators throughout the NOTL Hydro distribution system are being replaced by polymer insulators. Porcelain insulators served the industry well for many years, but over time, are subject to crack or break. Polymer insulators are time tested and not subject to that type of failure. The change reduces the incidence of pole fires, resulting in fewer outages.
  8. The effect of lightning strikes is mitigated through the use of lightning arresters throughout the NOTL Hydro distribution system. In most cases, lightning arresters effectively reduce the impact of the lightning strike and redirect the unwanted energy safely to ground.
  9. Reclosures are installed throughout the NOTL Hydro distribution system to turn what could be a long duration outage into a momentary interruption. For instance, if the contact was temporary such as a falling branch making contact but not staying on the line, then the reclosure can bring the line back in a very short period of time…sometimes only just long enough to require you to reset your clocks.
  10. Automated switches are being installed as part of the smart-grid program. NOTL Hydro has switches throughout the system which allows power to be rerouted. These can be used to reduce the number of customers affected by an outage. Most of the switches are manual which means our crews must go to the switch to operate it. Automated switches allow these changes to be made remotely using our Supervisory Control and Data Acquisition (SCADA) system.

Finally, this is not new or a change but one of the practices at NOTL Hydro that keeps our outage durations down is the willingness of our line crews to restore power during a storm. Remember them as the storm rages and the winds howl, and the community power restoration process is actively being worked on.

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