Arizona Public Service’s predictive maintenance group used a drone to inspect power lines for damage and vegetation growth at the Turkey Creek Trail East Parking Lot on the morning of Monday, Feb. 24.

The company’s drones carry high-definition and infrared cameras and allow crews to inspect Village of Oak Creek power linesf or regular wear and tear, vandalism, vegetation encroachment, sun damage and debris such as mylar balloons or the occasional trampoline. The drones are also equipped with GPS. The infrared cameras allows APS to detect hot spots and identify potential defects that may not be visible through regular inspections.

“A hot spot is going to be anytime there’s a high resistance connection,” APS preventative maintenance technician Jaryd Burt said. “Electricity, when flowing under normal circumstances, produces almost no heat. When there’s a high resistance connection, that’s going to produce a hot spot. That component has started its path to failure. But with infrared, we can catch that failure in advance, we can make planned, scheduled outages and repairs to replace those items.” 

APS drone inspections typically require a pilot, a visual observer to monitor the airspace and an inspector.

The Federal Aviation Administration requires that APS maintains a constant line of sight with the drone at all times. Under ideal conditions, such as on a clear day, operators can see a drone from a mile away, although terrain and weather can limit visibility.

“Typically, what we do when we start preparing for flights like this is we pick a staging area where we know and we’re going to fly a mile this way or and a mile [in the opposite direction],” Burt said. “After that point, we’ve inspected two miles in line; we then pack up forwards or backwards, and then do another two-mile stretch of line. That’s typically how our workflow takes place.”

Burt said that APS employs about 15 certified drone pilots and operates a fleet of around 20 drones. APS also has a designated sustainability drone pilot and four pilots in predictive maintenance, who are usually tasked with infrastructure inspection.

Each drone has enough battery life for about 22 minutes of flight time and APS can inspect between 20 and 30 poles per flight charge.

“You’re looking at roughly about a minute per structure is how much time we’re spending on [inspecting] each distribution pole,” Burt said. “The higher we go up in voltage … those inspections can go longer. On the big lattice towers, we’re doing maybe only four or five per battery. We’re looking at those for four or five minutes apiece.”

APS conducts annual inspections of all distribution lines in fire mitigation areas, which includes the VOC, typically between Jan. 1 and May 1. All necessary repairs must be completed by May 31, when the company is required to submit reports to federal regulatory agencies.

After this deadline, APS shifts to inspecting lines in non-fire mitigation areas, and those areas typically undergo inspections every five to 10 years, depending on voltage of those lines.

“We have a special team that uses an AI program to analyze various environmental factors, including humidity levels, wind conditions, ground moisture and overall dryness. The program processes this data and generates scenarios to help assess fire risk,” APS Supervisor of Construction and Maintenance Susan Young said.

Young said that APS has started using algorithms for wildfire smoke detection in the Verde Valley, with one system currently in place in Oak Creek Canyon and another installed in the Jerome area, and two more planned for future deployment in the Verde Valley.