We take them for granted, but the utility poles that line city streets, travel alongside railroad tracks, and follow country roads are some of our most essential infrastructure. They carry the cables that keep the lights on, broadband running, and many TVs and phones connected to service. But power poles and related equipment are susceptible to damage from weather, fire, insects, and other causes, which can result in power outages.
As poles age and degrade, it takes an increasing amount of inspection and maintenance to keep the 185 million electric distribution poles crisscrossing the United States and Canada reliable. That’s why some companies are turning to drones to make this work faster, cheaper, and safer.
Here’s how drones can make inspecting distribution poles — the ones that bring low-voltage electricity to houses and buildings from substations — easier and better.
Drone utility pole inspections by pole material
Our communications and power systems require regular visual inspections and intrusive examinations of utility poles to ensure safety and reliability. Utilities like Southern Company seized on the potential of drones for everyday operations early on, recognizing how they could dramatically improve transmission and distribution line inspections.
Drones make it possible to easily see the status of the entire height of poles without putting field workers at risk from climbing — and without an expensive bucket truck. Distribution poles range from 40 to 80 feet tall, and they come in four types: wood, steel, concrete, and composite. Drone technology can speed and enhance data collection on all four.
Wood utility pole inspections
The list of things that can prematurely age wood utility poles is long: woodpeckers, squirrels and other rodents, termites and wood-boring beetles, fungi, lightning strikes, the elements. Since the great majority of utility poles in North America are wood — an estimated 150M of them — keeping them in good shape is a big job.
Wood poles are usually inspected every five to 10 years, depending on local regulations. The work has traditionally included sounding poles with a hammer to assess rot, excavating around the pole to see ground-line decay and termite signs, boring core samples to check for internal integrity, and gathering imagery from the ground.
Drones can provide a different perspective on pole inspections. Using payloads like high-resolution cameras and thermal sensors, drones can fly the full height of poles to:
- Assess whether hardware at height needs tightening due to pole shrinkage.
- See the extent of bird holes.
- Inspect the integrity of the grounding wire and related equipment.
- Check for evidence of ants or termites.
- Get images of split pole tops, broken crossarms, damaged or missing insulators or brackets, fraying guy wires and support cables, and lightning damage from above.
- Quickly fly a long line to document tree limbs and other vegetation that may be encroaching.
- Find failed lightning arrestors.
- See and document horizontal cracks that may weaken the pole.
- Monitor large knots that could result in pole weakness over time.
- Document and assess burn marks from transformer failures or conductor faults.
The key differentiator when using drones for pole top inspections is that they take a fraction of the amount of time of traditional methods while significantly reducing the risk of electrocution or falls to workers. Drones can’t replace every part of a thorough pole inspection, but conducting easy, data-rich inspections on a more frequent basis could improve the reliability of the energy grid and identify problems before they happen.
Concrete utility pole inspections
Concrete poles are common in places where wood poles are prone to rot and termites, typically areas with high humidity, salt, or periodic flooding. They’re also used in places prone to fire or extreme weather such as hurricanes or blizzards.
However, cement electricity distribution poles can deteriorate from road salt application and pollution. It’s important to catch exterior pole damage to head off corrosion of internal reinforcing steel bars.
- Gather much of the same data and insights as collected for wood pole inspections.
- See and document cracks and fragmentation.
- Assess pole wear and pole top components
Steel utility pole inspections
Steel is stronger than both wood and concrete, making steel utility poles a popular choice to carry heavier loads. According to the American Iron and Steel Institute, steel utility poles are also the most durable, easy to install and maintain, and 100% recyclable.
However, because many steel poles are taller than wood poles, getting visibility into what’s going on at the top can be quite dangerous for field crews. Another drawback is that steel conducts electricity, so in the event of a power line failure the whole pole could become electrified.
For steel utility poles, drones can help inspectors:
- Closely examine pole shafts for areas of rust, corrosion, and any dents or signs of structural compromise.
- Record structural shifts of poles or pole top components over time.
- Check brackets, crossarms, and welds for metal fatigue.
- Ensure handhole and nut covers are in place.
Composite utility pole inspections
An estimated 1% of all utility poles worldwide are made of some form of fiberglass. While they typically require less maintenance than traditional wood or concrete poles, they can deteriorate from weather and UV light exposure.
On composite utility poles, drones can:
- Find and document scratches, cracking, gouges, and impact damage that could have compromised the laminate.
- Inspect for signs of charring from fires, lightning strikes, and electrical tracking from insulators to crossarms.
- Verify open holes (used for steps or climbing attachments) are plugged.
- Inspect hardware attachments for proper position and wear: through bolts, pole bands, crossarm and brace hardware, mounting brackets, slip joints, washers, pole steps, climbing ladders, fall arrest systems, guying tees, and guy wires.
- Detect loss of gloss, color fading, yellowing and other signs of potential laminate damage.
Other advantages of drones for power line inspections
The cables strung between utility poles get more fragile with age. Big temperature swings, birds, ice, and wind can cause cable strain, sag, and eventually breakage. Drones have made it possible to capture much more granular information about the condition of cables. And drones can do it at a speed that makes it possible to do inspections more frequently.
Drone speed is also an asset when things go wrong. Pinpointing the precise location of a short circuit, blown transformer, cable break, or other problem is crucial when there’s a power or cable outage. Uncrewed aircraft can help field crews find such problems faster, especially when rough back roads are involved.
Reducing cost, risk, and errors
A utility pole drone inspection program can help head off conditions that result in power and cable outages. Drones enable horizontal infrastructure managers to monitor assets more often, and more cost effectively, so they have timely information on what needs attention. They can direct maintenance to priority needs and extend the lifespan of their equipment.
Plus, drones minimize the risks of inspection worker falls and tool drops. They make it possible to survey the full height of structures from the ground. They reduce the amount of driving on rough backroads and trekking over tricky terrain during rural power line patrols. Ultimately, drones are a game changer for crew safety in utility and telecom field operations.
Want to learn more about how utilities and energy companies are putting drones to work? Check out Skyward’s guide: Drones in Energy & Utilities.