4.4 POWER OUTAGES Most of us take electricity for granted. However, when the power goes out, it becomes headline news! What is a Power Outage? A power outage (also called a blackout, power failure, or power cut) is the planned, or more often unwanted, loss of electrical power to an end user. Power outages can occur throughout the grid, for many reasons. Power outages often impact a single neighbourhood or local community but can potentially be city-wide or even province-wide or beyond.
Power Outage Causes The electricity system in Canada is expansive, and although the grid is engineered to provide safe and reliable service, at times issues can arise. Some of the external causes of power outages are shown below. •
Interruptions can be caused by electrical distribution equipment being exposed to abnormal environments, such as road salt spray, humidity, corrosion, vibration, fire, or flooding.
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Adverse weather conditions such as extreme rain, ice, snow, wind, extreme temperatures, freezing rain or frost can all cause damage to distribution infrastructure.
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The energy released during a lightning strike is usually mitigated through specialized equipment. However, lightning strikes can sometimes cause major damage.
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In urban areas, trees are sometimes allowed to get too close to power lines, creating safety and reliability issues. Electrical utilities usually have robust tree-trimming programs to manage this problem.
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Other foreign objects can cause power outages, including events such as animal contact (squirrels and birds), vehicle accidents, unsafe excavations, vandalism, and even objects such as metallic balloons.
Defective Equipment Defective equipment includes failure of electrical distribution system components primarily due to aging. Large capital investments keep these failures in check by replacing aging equipment. Loss of Supply Loss of supply can occur due to problems on the provincial transmission system. Scheduled Outages Scheduled outages are planned in advance for construction or preventative maintenance. This is the only category that utilities can fully control. Unknown Sometimes an outage will occur and even after investigation, no obvious cause can be found. Power gets restored and the event is registered as unresolved.
Electricity Canada | Electricity Fundamental in Canada: Student Handbook
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