What It Takes To Keep The Lights On!

By VERNON ROBISON

The Progress

The place is known by Overton Power District #5 (OPD5) crews as Rattlesnake, and it is just as foreboding as its name. In short, it is a maintenance nightmare!

A large wooden power pole structure is perched atop a craggy hill to the north of Logandale. There is nothing but shear cliffs below the structure. That makes it impossible for a road to be built up to the site.

So the only approach for work crews is a rugged half-mile hike on foot around the back side of the mountain. Any tools, equipment or parts needed in maintaining or repairing the structure have to be packed in on foot. And with no bucket truck or other vehicles able to reach the site, maintenance crews have to do it the old-fashioned way: by scaling the 65-foot-high poles.

That was the challenge faced by OPD5 line crews recently when it was discovered that extensive repair work was needed to support the Rattlesnake structure.

About a year ago, a routine OPD5 drone inspection at Rattlesnake revealed that the wooden support arms on the structure were beginning to split. Without reinforcement, it was only a matter of time before they failed. And no one could predict when that might happen.

Unfortunately, Rattlesnake is a very crucial spot in the OPD5 transmission system. It has long been part of the only main artery delivering power from the district’s hub at Tortoise substation in Moapa to the Sandhill substation on the bench east of Logandale. From there a transmission line carries power across the Mormon Mesa east to connect all of Mesquite.

Currently, there is very little redundancy to that line. If it goes down, there is an old power line that might carry enough to energize Moapa Valley. But it doesn’t have near enough capacity to feed Mesquite.

“If we were to unexpectedly lose that structure, I’d bet that we would, at the very least, be seven days getting it back online,” said OPD5 Line Operations Manager Corey Dalley. “Because you don’t know what kind of damage is going to go downline or upline from there since it is way up on that point. We really didn’t want to leave something like that to chance.”

The problem is that the line can’t be de-energized to do repairs without blacking out all of Mesquite for an indeterminate amount of time. Thus, the only option for OPD5 crews was to perform the repairs while the line was still energized, Dalley said.

That would be a unique challenge. That line carries 138,000 volts. A person coming within 10-15 feet of the line itself would start to feel some mild effects of stray voltage. And the closest a worker could safely get to it while energized would be four feet.

“So our crews would have to climb up those power poles,” Dalley said. “And everything they do, all of the intricate work in pulling cotter pins and loosening and tightening things down – all of that would have to be done at the end of a fiberglass pole rated to handle the voltage. It is a tall order.”

Dalley said that this kind of work on a live line is not routine for OPD5 crews. “Our lineman have the basic training to do that kind of work, but they don’t get much experience with it day to day,” Dalley said.

Instead, the district usually calls in a contractor for that kind of job. Dalley said that he called a couple of contractors last year. “They took one look at the location and wouldn’t even consider trying to do it,” Dalley said. “So it became an in-house job by necessity.”

Last Fall, OPD5 Overton Area Foreman Kyle Leavitt took the project on as a challenge. He and his crew began studying the Rattlesnake structure, taking detailed measurements and doing careful calculations of line tensions and weights. They used these to build a practice structure in the OPD5 equipment yard in Overton that precisely replicated the one at Rattlesnake.

Then they went to work rehearsing exactly how to reinforce the splitting arms on the structure. Over a series of about four months, the team spent more than 40 man hours just practicing that procedure and working out every possible detail.

“They tried all different scenarios and different types of techniques, just trying to anticipate every contingency,” Dalley said. “Because once you’re up there working on a live line, there is no turning back. You have to keep going until it is done.”

In the end, Leavitt and his team presented a detailed plan to OPD5 General Manager Mendis Cooper and other district managers to seek the final go-ahead and move forward.

“Obviously Mendis was concerned about this being our main artery,” Dalley said. “If we have a problem up there, it is going to shut everybody out of power. But Kyle just said, ‘I wouldn’t be doing it if I wasn’t 100 percent confident that we could get it done.’ So he was given the green light to move forward with it.”

A crew of nine workers assembled at the foot of Rattlesnake on March 23 at about 7 am. They included linemen Steve Barlow, Chad Dalton, Cody Hardy, Ben Jantz, Luis Gonzalez, Omar Vallejo, Tanner Kilmer and Zach Barnum; with groundman Michael Abbott assisting.

The crew hiked all of their gear up to the hill and got started working on the project by around 9 am. They took turns with four of them working up on the pole for half of the day while the others supported from the ground. Then the other four spent the latter half of the day on the pole.

“Everything went pretty much exactly as they had practiced it,” Dalley said. “There was very little variation from that. It was very well done.”

By the time the crew was finished at about 3:30 pm, the structures were reinforced and the problem was solved for the time being.

Actually, the district has been planning for some time now to avoid situations like this in the future. The plans would add redundancy to the system to make maintenance on transmission lines easier.

First of all, there are plans in the works to eventually reroute this vital 138 kV line around Rattlesnake so that every structure on the line is accessible by road.

Even sooner than that, though, a second 138 kV line has been planned to be constructed across the mesa directly to Mesquite. That line is expected to be completed as soon as late 2022 or early 2023.

“At that point there will be redundancy going into Mesquite,” Dalley said. “And we will have even better redundancy for Moapa Valley because we can use that line to feed back to Logandale and Overton if the other line goes down.”

Dalley praised the work of the crews who saw the difficult project to completion. “There is a lot of gratitude for these guys and the things that they were able to accomplish,” Dalley said. “They could have just said ‘No it can’t be done.’ They could have insisted that we find a contractor to do it. But they spent the time and worked out the problems and got them solved one by one. It was a remarkable job that they did.”