Relying on ground teams and helicopters to inspect assets can lead to incorrect data, safety issues, and damage to the environment. Here’s how Dominion Energy improved all three metrics through a drone-based inspection solution.
Traditional Inspection Methods: The Challenges
Dominion is a power and energy company that operates in 16 states and maintains over 6,600 miles of overhead electric transmission lines in Virginia, North Carolina, and West Virginia. When it comes to Comprehensive Visual Inspections (CVIs), every utility needs fast, accurate data. But Dominion, like all utilities, has two additional areas it’s focused on: the safety of its workers and environmental protection.
The utility’s traditional methods of conducting CVIs were to send out ground teams and helicopters–methods that can make it challenging to meet these needs due to the following factors:
- Accurate data: Helicopter teams are limited in how close they can get to structures and what camera angles they can provide. Ground teams and lineworkers may have trouble accessing the areas they need to inspect.
- Safety: Helicopter missions can be dangerous; pilots need to maneuver their helicopters without colliding with hard-to-see lines or transmission towers. Ground crews and lineworkers can face dangerous conditions like swampy areas and downed electric lines.
- Environmental protection: Aviation emissions contain nitrogen oxides (a family of poisonous, highly reactive gases) and particulate matter (microscopic solids or liquid droplets in the air that can affect health).
Given these challenges, Dominion decided to replace some of its helicopters and ground crews with drones to improve data fidelity, safety, and environmental impact — tapping geospatial data analytics provider PrecisionHawk to run a two-year proof of concept.
Putting Drone Collection to the Test
“What we wanted to do was, at a minimum, recreate the CVI inspections that we did with a helicopter so that we weren’t losing anything,” says Steve Eisenrauch, Dominion’s Manager of Electric Transmission Forestry & Line Services at the time. “That was our baseline. And then we wanted to see if there was anything additional we could get.”
Eisenrauch contracted one of the utility’s retired lineworkers to shadow PrecisionHawk’s teams for the first six months. “We wanted to make sure that they were conducting business in a safe manner, and also that they were conducting business in a way that was respectful to our customers,” he recalls.
“We also wanted to provide them insights as to what the utility was looking for in terms of defects. So, the lineworker spent time with them understanding their process, and then helping them understand what we’re looking for.”
To test the drone-based CVI concept, Dominion selected a transmission line to fly with a helicopter and then flew the same line with a drone a couple weeks later to compare the results. “We found that the drone really picked up on more issues on the poles than the helicopter did,” Eisenrauch says.
“This was attributed to the drones being able to get in and see different angles on the structures that helicopters could not. Helicopters are not able to get that close in and easily change positions on the structure. So, we were very pleasantly surprised.”
(Too Much) Good Data
Over time, the team learned what constituted an Area of Concern (AOC) and refined their data collection down to exactly what needed to be collected.
“The additional detail has been a bonus for us,” says Eisenrauch. “Our goal was to at least be able to duplicate what a helicopter does–and then there were the other benefits around using a drone in place of a helicopter: it’s less intrusive to our customers, there’s a better environmental footprint, it’s potentially safer, and it was nice to get the additional angles and pick up on additional defects.” Overall, the drone-based program identified 42% more AOCs, such as cotter keys backing out and flashing on insulators.
Fast forward to today. Dominion continues to utilize drone-based CVIs, Steve Eisenrauch is now the Manager of Electric Distribution Contractor Resource Management, and the new Manager of Forestry & Line Services is Angelita Gardner-Kittrell.
Many utilities have their inspection teams capture a standard set of images and send them to their data engineers for analysis. But other utilities, like Dominion, do their inspections in real-time: the teams inspect each structure, but take images only of equipment and components that meet the criteria to be considered an AOC for Dominion Energy.
How it works: one or two crews, each consisting of a pilot-in-command and a sensor operator, work to efficiently inspect 30 or more assets per day. They use multi-rotor drones outfitted with a sensor with an optical zoom lens, which allows the pilot to capture crisp images of each asset. The sensor is so high-resolution that the pilot can even read the serial numbers on the hardware.
Images showing AOCs are then transferred to Dominion’s analysts; they then inspect the images to ensure they depict AOCs, and put together reports for the utility’s key stakeholders. If any critical findings are uncovered in the field, such as missing bolts, backed out cotter keys, or cracked insulators, the necessary teams are notified immediately so that repairs can be expedited.
One benefit to in-the-field inspections versus the traditional method of inspecting the data after collection: “When PrecisionHawk goes out, they’re identifying the defects and not just taking pictures,” says Gardner-Kittrell. “That eliminates the amount of data that has to be sorted through.”
PJM, the regional transmission organization of which Dominion is a member, requires utilities to perform CVIs, at a frequency determined by the individual utility. CVIs conducted on Dominion’s entire system are completed every six years with a combination of drones and helicopters.
Extending to Emergencies
Dominion also utilizes drone-based CVIs for emergency inspections. For example, after a storm hit the Outer Banks in North Carolina, they focused on situational awareness across 50 miles of transmission lines in strategic locations where the utility was experiencing power outages. They could easily see where a tree had taken down a line, report the situation and immediately send out a repair crew. By utilizing drones, they were also able to view the situation from above and help safely guide crews to the right structures.
In addition, Dominion conducts pack-out inspections, where their teams climb transmission structures to get an up-close look at potential problems like rust at connection points. For the parts of the structure that aren’t easily accessible, Dominion again uses drones to increase both data accuracy and staff safety.
Dominion has been impressed with the safety of drones. “We haven’t had any incidents,” says Gardner-Kittrell. “And of course, if there were some type of incident, a drone crashing would result in fewer injuries.”
The increased accuracy that comes from being able to take sharp images and capture difficult angles has enabled Dominion to take quick action on potential problems, which reduces downtime and increases customer satisfaction.
And then there’s Dominion’s goal of decreasing its environmental footprint. Dominion estimates that their drone use saves approximately 500 flight hours equaling a savings of roughly 2,000 gallons of jet fuel burned.
Thanks in part to the PrecisionHawk solution, “Each year, we’ve been increasing the number of structures we inspect,” says Gardner-Kittrell.
Over time, Dominion hopes to automate the processing, analysis, and reporting of its inspection data using an AI-powered solution like PrecisionHawk’s PrecisionAnalytics Energy–and also to expand their use of drones so they can continue to improve safety, accuracy, and their environmental footprint.