What causes service interruptions?

If we look at statistics for cooperative electric service in Oklahoma, we find, on average, electric service is available 99.9% of the time. Another way to look at that statistic is power is off less than a total of 8 hours per year. Averages, however, can be misleading. You may avoid a service outage for several years and then have a multiple-day outage from an ice storm.
Since becoming a member of CKenergy Electric Cooperative in 1974, service has continually improved with blinks and outages decreasing over the years—although from time to time they still occur. In 2017, we built a home served by Oklahoma Electric, northwest of Newcastle. In the four years we have lived there, we’ve had about 18 total outage hours, and most of those occurred during the October 2020 ice storm. From my experience, service reliability is very high.

What are the most common causes of interruptions to service?

Lightning, high wind, fires under the lines, accidents and other simple reasons can cause an “instantaneous outage” that only lasts for a second. They are annoying because your tv or internet reboots, your microwave sometimes needs re-setting, or there’s a quick blink of your lights. Occasionally, this is caused by an electrical equipment issue, but mostly it’s nature. If it persists and occurs more than you think reasonable, contact your cooperative because it can be equipment-related.

Each substation has some type of protection to prevent damage to equipment that could lead to long outages. This protection generally is in the form of fuses, lightning arresters and circuit switchers. They can be re-set in a short amount of time and service restored. Faults from lightning, wind, other weather and critters getting into places they should not go are the most likely activities that cause outages that last a few minutes to a couple hours.

Heavy thunderstorms with high winds, tornadoes and ice storms can cause more lengthy disruptions and outages. These events cause significant damage to power lines. Sometimes power can be rerouted and service restored quickly. Other times, replacement and reconstruction of the power line has to occur before service can be restored. If it is a pole or two, restoration can occur sooner than if it is 10 or 100 poles. Major ice storms can destroy entire areas and take days to fully restore. Many utilities have “mobile substations” mounted on large trailers that can be used to restore that type of outage quickly while repairs are being performed.

One of the newer innovations I use a lot that CKenergy, Oklahoma Electric and other distribution cooperatives provide, is an internet outage map that shows where and how many outages are occurring and to which outages crews have been dispatched to correct problems. Many cooperatives also use social media to keep consumers updated on outage restoration.
Reliability and improving reliability is always a goal of cooperatives; keeping members online is also a high priority. Everyone—both electric consumers and cooperatives—has a 100% reliability target they try to reach, but every now and then Mother Nature doesn’t get the message.

By Gary Roulet

Board President | Oklahoma Association of Electric Cooperatives