Stringing Power Lines Reduce Safety Risk To Workers

Although drones are hardly new to the power industry in our country, power lines stringing is a fairly new application, one that offers substantial savings in terms of time and money. This could change the way power companies work permanently.

Matt Dunlevy founded SkyScopes as a spinoff while teaching a class at the business college at the University of North Dakota in 2014. This is when Dunlevy saw the potential for drone service providers in the area, even though flying legally required a Section 333 Exemption from the FAA. Just a year later, SkySkopes became the first startup in North Dakota to receive permission to fly commercially.

Power Line Stringing

Matt Dunlevy, President and CEO of SkySkopes, is one of the top Drone Service Providers globally, and was the first drone services company to introduce power line stringing in the U.S. Energy companies such as Xcel Energy and Duke Energy and others are working together in this new approach in the industry.

Stringing high-voltage power lines between towers is a job that is fraught with danger. Therefore, it is a specialized and challenging work which is traditionally done by helicopters. However, a North Dakota company has demonstrated that drones can pull off a “sock pull” with less risk and expense.

The term “sock pull” describes stringing lightweight lines known as “socks” over pulleys and stretching the rope to the next tower so that the much heavier power cable can then follow. During a line string, a worker relays information using hand signals to the drone pilot flying the “line bird” (the drone).

The process is explained in the following way by Dunlevy:

“The flight first takes place at the base of the structure, and then, depending on battery power and endurance, the aircraft will ferry the line in the air to the next tower in the corridor. After the aircraft detaches the line, it lands: we replace batteries, rinse, and repeat.”

Dunlevy also addresses the issue of danger:

“Weather, terrain, daylight, climate, and other factors affecting UAS missions in general are magnified when stringing lines. Sometimes the line itself, a pseudo-tether, can act as a safety measure in case a UAS would want to fly away… We’ve never had to use it this way, but we see it that way. Other challenges include the types of pulleys and the height of towers.”

In the past, a project would be completed by either workers who physically climbed the towers, exposing thus themselves to hazardous heights, or with helicopters manned by pilots, which was extremely expensive.

These lines were some of the most massive in the country and at 765 kV, they proved that the mission can be done with UAVs (drones) on any type of power line.

In addressing this innovative aerial solution to the energy sector, President Dunlevy, said:

“We primarily use drones to fly LiDAR, Optical Gas Imaging, and EO sensors to produce actionable intelligence for utilities and oil companies. The organization has offices across the United States including in California, Texas, Minnesota, and North Dakota.”

While power line stringing has been a success, it is still fairly new to the industry.

According to Dunlevy, “Right now 99% of these types of operations are being done with traditional methods. Many potential adopters are unaware of the new methodology, cost savings, and time savings.”

The process is cheaper and faster than conventional methods, but it does require skilled pilots. In fact, pilots are chosen for sock pull duty based on their experience, certifications, and demonstrated skill.


Commercial drones adapt to many business purposes as they can perform tasks that formerly posed great difficulty and severe risks to workers.

Power line stringing is yet another market for which drones are ideally suited. They can save time and money, while reducing risk to workers.The future for drones stringing power lines is extremely bright since this new approach could change the way power companies work, permanently.

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