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How We Meet Power Reliability Standards

November 02, 2015
Published In: Power

​And yet behind the power sockets in your home is a vast, interconnected grid that starts with power generators, moves through a distribution and transmission network, and ends with the meter at your home. 

All of the magic that makes your lights shine happens in real-time: We're working around the clock to keep the power flowing, with skilled employees working to build, operate, maintain and monitor the grid.

At the same time, ever-growing demand to power our buildings, devices, cars, industry, schools and hospitals is putting an increasing strain on an aging system, requiring significant investment to continue to meet our standards for power reliability.

The EPCOR Power Grid

In the City of Edmonton, we deliver about 13.5% of all of Alberta's energy consumption to about 369,000 customers. That's 7,757 megawatt-hours of electricity moved through:

  • 5,390 circuit kilometres of primary distribution lines
  • 5 distribution substations
  • 257 circuit kilometres of high-voltage transmission lines
  • 30 transmission substations

Stretched end-to-end, our wires could span over two-thirds of the TransCanada Highway. 

Power Reliability: How are we doing?

In 2014, each EPCOR power customer in Edmonton experienced an average of one power outage lasting a little over an hour. (See Power Distribution & Transmission Reliability Indicators, below)

For comparison, the average Canadian experienced two-and-a-half outages lasting nearly five hours on average, according to the Canadian Electricity Association. That doesn't include major event days that would push those numbers even higher. (We do count major event days, but didn't actually experience any in 2014.)

What causes these interruptions? For a large part, it's natural causes such as wind, lightning, freezing rain, tree branches or wildlife. But aging infrastructure failures, other interferences — such as damage to our equipment caused by traffic or people — and scheduled outages taken for planned maintenance are also major causes.

A growing grid for a growing city

Edmonton has been growing at an unprecedented rate, and our grid needs to grow to keep up. Downtown Edmonton, with the new Ice sports and entertainment district and new towers on the rise is a prime example of the challenge we face in continuing to deliver reliable power.

EPCOR is responding to these types of challenges by modernizing the infrastructure that delivers and meters electricity. For example:

  • Advanced meter infrastructure that will allow us to read meters, to pinpoint and respond to outages more quickly, as well as provide more accurate bills and reduce our operating costs remotely
  • An outage / distribution management system that will help us to monitor and control the distribution network more efficiently and reliably, and act on outages more effectively
  • Continuing with life cycle replacement projects for different assets (cables, switchgear, transformers, etc.) that help to improve overall system reliability
  • Installation of automated aerial and underground switches on selected circuits to reduce the impact of any outage in terms of both duration and the number of customers interrupted

Power distribution & transmission reliability indicators

Reliability numbers are based on industry-standard indices, which are (respectively): System Average Interruption Frequency Index, Customer Average Interruption Duration Index, System Average Interruption Duration Index, and System Average Duration Index.

Number of power outages that each customer experienced on average (SAIFI)
Duration of average outage, in minutes (CAIDI)604147
Duration of average service interruption experienced by customers, in minutes (SAIDI)635966
Overall reliability of EPCOR's electricity system (IOR)99.9%99.9%99.9%
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