Electric utilities find many uses for these tiny aircraft
When Randy Hutchison saw the first photos taken by the drone hovering near a tower supporting high-voltage transmission lines, he was amazed. “I was surprised at the quality and how detailed the images were,” Hutchison says.
And Hutchison’s no stranger to the tiniest details of those massive support towers. As vegetation management supervisor for Big Rivers Electric Corporation, the Henderson-based generation and transmission cooperative that keeps the power flowing to local distribution co-ops in 22 counties in western Kentucky, he’s logged hundreds of hours in helicopters inspecting the right-of-way. He knows exactly what to look for, and how to spot problems 100 feet up in the air.
Earlier this year, as he and Big Rivers line supervisor Brandon Osborne discussed the best way to solve a problem along a section of a power line corridor, they realized this would be the perfect situation to test out a drone.
Keeping it safe—and legal
They knew they’d need something much more reliable than the lightweight drones sold at the local hobby store. Not only that, they’d have to figure out how to comply with Federal Aviation Administration (FAA) rules and regulations, state public service commission rules, industry safety standards, insurance, and multiple other checklists to keep it all legal.
They connected with Brandon Schulz, manager of United Aerobotics, a division of United Dynamics Corporation, headquartered in Brooks, a company that provides drone services to utilities in three countries and 26 U.S. states.
In the world of aviation, drones are known as unmanned aircraft systems (UAS)—but the “unmanned” part of that description is somewhat deceiving. While it’s true that no human is riding in or on the device up in the air, the FAA requires at least two humans be on the ground when using a drone. One person must maintain eye contact with the drone at all times.
A big advantage to using a drone for transmission line inspections is that the line can continue to be energized while it’s being examined. While that keeps service reliable, it also presents a serious hazard.
“It’s all about safety in this line of work,” Schulz says, “so we maintain flight patterns with a large margin for error. We must stay out of the arc flash boundary zone, at least 10 feet away from the power lines themselves. We try not to fly directly over the lines, and instead perform our inspections flying alongside at different angles.”
More uses, better rules
“The drone we use is a battery-powered, six-blade, ‘hex rotor’ model that weighs about 15 pounds,” Schulz says. “Although it has a top air speed of about 30 mph, we seldom go that fast. In fact, we go very slow. The vehicle we stage from is a six-wheel ATV that can handle the terrain in the right-of-way. Most of the time we send the drone up, hover from various angles, bring it back down, then reposition at the next support tower, and repeat. We do not fly while the vehicle is moving.”
As well as drones work for outdoor transmission line inspections, they’re also turning out to be very useful inside structures at power plants. Schulz says, “We can fly our drone inside confined spaces such as stacks, tanks, boilers, and ductwork. There’s no GPS when you fly a drone indoors, so it’s all pilot skill when flying in these tight quarters. And it’s dark inside them, so the drone has floodlights and spotlights to help us look at whatever needs to be inspected.”
Drones might be useful as workhorses, too. One electric utility envisions using a drone to pull a lightweight messenger cable that linemen could then use to pull the heavier electric cable across a steep ravine or swift-water creek.
The National Rural Electric Cooperative Association is working with Congress and the FAA to fine-tune laws to increase the usefulness of unmanned aerial systems. Read the proposed bill at ECT.coop by searching “Senate drone bill.”