Recently, residents in western Carteret County, including Bogue Banks, experienced a series of power blinks. A faulty transmission line insulator (pictured below) was the culprit in power interruptions all along the section of line that runs from our transmission substation in Maysville to Pine Knoll Shores and serves 20,600 homes and businesses.
Crews were able to quickly identify the problem, reroute the transmission feed and replace the insulator. By transferring the power, crews were able to prevent further disruptions to members. By early that afternoon, the electric distribution system was operating normally.
Why does the power blink?
Blinks are created when a breaker opens along any portion of the power system. This happens when a relay senses a problem (fault) on the line and tells the breaker to open, preventing the flow of power to the problem site. After opening, the breaker quickly closes. The brief delay, which allows the fault to clear, may last anywhere from one to thirty seconds. The breaker can open and close up to three times in an attempt to clear the problem. If the problem remains, the outage will be longer. Our crews will need to identify the problem and make repairs before electricity can be restored. In the event of a transmission blink, thousands of homes and businesses will experience a short interruption.
If the system was designed without the ability to briefly interrupt the flow of electricity and did not blink, every interruption or contact with an energized line would cause an extended outage that would not be restored until co-op crews address the problem.
What about the loud boom before an outage?
Many people think that the loud noise they hear before an outage is the sound of a transformer exploding, due to lightning or other extreme conditions.
That’s not usually the case. More likely the sound is from a fuse blowing. Our power lines use fuses—big ones—to protect parts of the distribution system. The noise can be substantial, leading many people to think something has exploded.
Does salt buildup cause outages?
Salt contamination and corrosion are not uncommon on the cooperative’s lines, particularly those close to the ocean and sounds. Often during warmer months, a lack of rain causes salt to build up on the insulators. A dry layer of salt usually does not cause blinks or outages, but the combination of salt and small amounts of moisture can cause arcing, sparking, blown fuses, pole fires and extensive power outages. This can be easily seen on the beach at night if you look at the insulators and see small flashes of light, but is normal for this time of year. A heavy rain is needed to remove salt buildup from equipment.