Unmanned Aerial System program continues to soar

Developing a program

In the early stages, the UAS program was focused on improving the reliability of the worst performing feeders. The primary measure of a utility’s reliability is called the System Average Interruption Duration Index (SAIDI), which measures the average downtime per meter. This is a metric we wanted to improve and were able to do so thanks to these efforts. These significant improvements in reliability­ — with great return-on-investment — led PEC to formalize the UAS program.

“The primary objective of the UAS program is to perform preventative maintenance that reduces SAIDI minutes, which means less power interruption time for our membership,” explained Regional Operations Director Kurt Buckner. “This is in conjunction with increased safety for our employees and large cost savings for the cooperative.”

After a UAS inspection of a Spicewood area feeder, PEC conducted equipment maintenance based on the report. As a result of the improvements, the SAIDI in that area dropped 7.5 minutes. Any SAIDI improvement over one minute is considered exceptional and is quite rare.

Today, PEC’s UAS system operates as a methodical five-year maintenance program in which every pole in the district is inspected. Working systematically outward from each feeder and inspecting every line was simply not feasible with traditional methods and would have required two journeymen, a bucket truck, and at least an hour to inspect four poles. With a UAS, a single pilot can inspect 5.5 poles in that same time. This level of efficiency results in a 90% savings — on top of improving reliability and the safety of our workers.

This program also requires coordination with just about every department at the cooperative; including technical services, planning, system engineering, vegetation, and environmental.

Aerial assessment

Power lines are inspected starting from the feeder and working outward. A feeder is a line that carries power from the substation to the lateral taps that connect our members to power. When immediate dangers are identified, a crew of lineworkers will be dispatched to complete repairs as soon as possible. When other potential issues, or “exceptions,” are identified, the maintenance team will document and create a workorder for each one.

The aerial perspective of a UAS has its advantages beyond speed. Because escaping electricity arcs up and out, equipment will often only be visibly damaged from the top. It can also be very difficult to tell from the ground whether nearby vegetation poses a threat to equipment.

Spotting problems, preventing outages

System Maintenance Supervisor Eric Bitzko is one of PEC’s UAS operators and our foremost expert on the subject.

“Instead of PEC crews and contractors knocking on doors and entering backyards one by one, we can fly our UAS along our easements to identify areas that require maintenance,” he explained. This method is less intrusive for our members, who are notified ahead of time if an inspection will occur in their area. The UAS captures only PEC equipment, and photos of private property are not shared outside the cooperative.

Once the review of each feeder is complete, a report is compiled for the maintenance crew who can then print or view the report on their phone or tablet. This report can be used to efficiently prepare the necessary parts and equipment and proceed directly to the location of required maintenance. The types of issues identified vary widely; from simple fixes like tightening bolts on cross arms, to more labor intensive jobs like replacing bad lightning arresters.

Ahead of the curve

Coordinating the UAS program with a maintenance crew has additional benefits beyond simply fixing visible issues. Working down the line allows the maintenance team to complete updates that keep them ahead of the curve on potential issues. Bertram Regional Operations Supervisor Doug Thompson explained that coordinating with vegetation management and engineering reduces the amount of reactionary maintenance they have to do.

“Any time we are working on an issue that was discovered with the UAS, we also complete updates and standardize things like fuses,” Thompson said. For example, his crew replaces existing lightning arresters — good or bad — with models that are easier to spot when they’ve blown, reducing the likelihood that a surge will cause an outage.

Making the most out of every climb up a pole has contributed to lowering the SAIDI numbers in Bertram. It’s easy to sense the pride Thompson has in this program when he talks about these results. “I really feel that the maintenance program our district has built is exceptional, not just at PEC, but nationwide,” he said.

Safety and savings

Thanks to this new technology, much of the work required for maintenance is done at a desk instead of in the field. Fewer crews are sent to job sites, and less dangerous work is conducted. The safety of our workers is our highest priority, and the UAS represents a major step forward.

As a nonprofit cooperative, our UAS program also provides a terrific return-on-investment that represents a great value to the cooperative.

“The ability to find and replace aging infrastructure has never been more affordable,” Bitzko said. “The price per structure is a fraction of the cost of traditional methods and dropping. In the not so distant future, industry leaders might be inspecting their entire system weekly, if not daily.”

How we protect your privacy

Our UAS is registered with the Federal Aviation Administration and follows best practices outlined by the Department of Defense and Department of Energy, as well as Texas regulations governing the use of unmanned aircraft. Our UAS program allows PEC to complete inspections without setting foot onto member property. Furthermore, our UAS only enter PEC’s right-of-ways, just as crews on the ground would do. We also notify members by phone in advance of UAS inspections.