Improving Reliability Through Technology — Drones to the Rescue
Approximately 61,600 poles make up the backbone of Sequachee Valley Electric Cooperative’s distribution and transmission system. Keeping these poles in sound condition is crucial to ensuring the reliability of service our members expect and deserve. “Each year, SVEC performs inspections on about 6,000 poles, about 10 percent of the total, to determine the condition of each pole and an estimate of how many years of service the pole has left before it needs to be replaced,” said Danny Kirkendoll, vice president of engineering and operations.
The majority of these inspections are “sound and bore” inspections performed by technicians who physically approach each pole. They first “sound” the pole by striking it with an instrument to identify any cavities hidden within the pole’s outer layers. They then “bore” it with a sharp tool that is driven into the pole to determine its resistance strength. This testing is limited to the area of the pole the inspector can reach from ground level. A visual inspection is then conducted to identify any defects in the pole’s appearance or equipment mounted on it. This inspection is limited to what the inspector can see from the ground. Helicopters are used to observe the areas on the pole-top structures not visible from the ground. The helicopter inspections are very helpful in locating obvious damages to a structure but are limited due to the distance the helicopter must keep from the power line.
The technology now available with the use of drones equipped with high resolution cameras allows us to find even the smallest defects in structures and equipment atop the poles. A series of three photographs per pole is taken, and the data is submitted to an inspection team to examine and report on any damages found. “The most important advantage to drone inspections would have to be the safety aspect,” says SVEC Safety Coordinator Donnie Cooper. “Inspectors can remain at a safe distance while working and never have to make contact with the pole. This also eliminates the need to traverse hazardous terrain such as creeks, ravines and fences. “Drones offer a more usable form of documentation. We have access to inspections that contain photographic evidence of the state of the structure and equipment when the inspection was performed. If further damage occurs following the inspection, the photographs will assist in determining the timeframe in which the damage occurred. “The 2022 drone inspections were carried out only months after the same structures had been inspected by the ‘sound and bore’ method. Although the inspectors who performed the ground inspections did a very thorough job, the drones were able to identify 32 issues that would need to be addressed in the near future to maintain reliable service to the substations dependent upon the nearly 1,300 poles along the 69kv transmission lines in Marion and Grundy counties. “Several more nonsevere issues were reported, which allows us to begin a plan of action before those issues become critical,” Cooper concluded.