Improving System Reliability

Our mission is to deliver reliable power, safely and efficiently. Through the systematic monitoring of reliability statistics, issues and root causes we continually strive to improve the reliability of our electricity distribution system.

The Alectra Utilities (formerly PowerStream) distribution system is valued at more than $1.3 billion (2014) and consists of 11 transformer stations connected to the provincial transmission system, 54 municipal substations, more than 5,000 kilometers of underground cable, more than 2,500 kilometers of overhead circuit wires and more than 44,000 transformers.

Lazenby Transformer Station - Hwy 7, Richmond Hill
Alectra Utilities distribution system consists of more than 5,000 kms of underground wire and more than 2,500 kms of overhead circuit
Greenwood Transformer Station - Hwy 407, Vaughan

Types of Outages

Outages may last a few seconds or a few hours, depending on the cause. There are two major categories of power outages, Momentary or Sustained, depending on the duration. In addition to these two types of outages, there are also planned power interruptions that are required for certain types of maintenance and repairs on the system. In these cases, Alectra Utilities notifies affected customers prior to the interruption.

A Momentary Outage is defined as a brief power interruption lasting one minute or less, but typically is only one or two seconds. While momentary outages are inconvenient, the automatic equipment on the Alectra Utilities distribution system helps to prevent longer duration outages.

A Sustained Outage is defined as a power interruption that lasts longer than one minute and may require Alectra Utilities staff to be dispatched to fix the problem. The time required to restore the power is dependent on many factors, but is often restored within hours.

Outage Causes

The most common causes of power outages are adverse weather (storms, tree contact and snow), animal contact, equipment failure and planned power interruptions. These and other common causes are defined further below.

Preventing Outages

We work year round to maintain, repair and upgrade the Alectra Utilities electricity distribution system. Some of the more common programs we execute on a cycle or as needed basis are as follows:

Who's Involved in Improving System Reliability at Alectra Utilities?

Operations and Construction; Engineering Design, System Planning and Standards; Transformer Stations and Substations Planning and Design; Customer Service and Key Accounts; and Smart Grid and New Technologies are all involved in improving the reliability of the Alectra Utilities distribution system and maximizing the performance of these valuable assets.