Hardliners

Posted: August 1, 2019

SVEC pilots new reliability tool — tree wire

When Suwannee Valley Electric Cooperative came to be, the task of building the first electric lines in this region fell to a handful of ordinary people willing to install poles and run wire so their neighbors could have electricity.

Today, SVEC’s workforce has grown to include crews specializing in maintaining the electric system, clearing right of way and even installing specific types of service. But it’s the construction department that carries on the legacy of the cooperative’s earliest builders by expanding the electric system to new members.

SVEC recently installed a new, tougher type of electric wire known as tree wire. The new wire is part of a pilot program SVEC is conducting in hopes of making the electric system more reliable.

Bryan Gamble, SVEC’s construction supervisor, oversees the four crews that make up the construction department. Each one has its own area of expertise, such as hooking up new homes, installing underground service lines or replacing single phase circuits and poles with three-phase to carry more electricity. In addition, they build new lines, replace broken poles, and inspect members’ property to make sure there is the necessary clearance from trees and undergrowth before installing new equipment.

Managing all those different tasks is one of the greatest challenges for Gamble. “It’s a juggling act. It can be tough to schedule work a week out because you don’t know what might happen,” he says. “It could be beautiful weather one minute, and then a storm comes up and causes a tree limb to fall on a line and knock the power out.” Fortunately for Gamble and his crews, they recently installed a new, tougher type of electric wire designed to withstand falling tree limbs. Known as tree wire, the new line is part of a pilot program SVEC is conducting in hopes of making the electric system more reliable.

Problem Areas

Tree wire is being tested in areas where outages from falling limbs are more common.

Unlike traditional electric wire, an especially tough coating insulates tree wire to reduce outages caused by contact with both wildlife and falling tree limbs. That’s especially helpful in areas where the cooperative’s lines run through areas thick with trees.

“Major storms can leave a lot of old tree limbs that are barely hanging on,” says Braxton Hicks, an electrical engineer in training at SVEC. “Later, the wind can come up, and these old, dead limbs fall on the line and knock the power out. Then we have to roll a truck out there to get it off the line and make repairs.”

However, because tree line is more expensive and can be difficult to work with, the cooperative decided to test it out in a couple of locations where large outages of this type are most frequent. Using data collected from the co-op’s outage management system over the last three years, SVEC identified about 70 problem locations throughout the entire system where members were without power for the most time.

Next, they looked at possible solutions. Could the line be relocated closer to the road and away from trees? Would automation technology help limit the amount of time members are without power by rerouting electricity around faults on the lines? Could the line be moved underground to protect it from debris during a storm? If none of those choices seemed viable, they considered replacing that section of line with tree wire.

The construction department started with two sections of line, totaling about a mile in length, where tree wire might improve service reliability for large numbers of members.

A Tougher System

Tree wire is more difficult to install
and work on but withstands much
more during severe weather.

Jason Carroll has already seen firsthand just how strong the new tree wire is. As a journeyman lineman and foreman for the crew that installed it for
the pilot project, the tree wire could be tough to work with at times. Stripping the protective insulation so they could connect the wire to other electrical
equipment proved particularly difficult. “It’s totally different from anything we normally work with,” says Carroll. “That tree wire is really tough. You can’t
get through it with just a normal pocket knife.”

As a result of that toughness, the sections of line Carroll and his team worked on have yet to experience an outage since the tree wire was installed. The engineering department will continue to monitor those sections over the coming months to determine how effective tree wire is at improving reliability.

Since going to the new and tougher wire, SVEC has yet to experience an outage in the areas it was installed

“We will keep track of how many times those lines go out and then compare it to how many times they have gone out in the past,” says Hicks. “That way, we will be able to tell if the project has been successful. We strongly believe that it will be.”

While tree wire isn’t an option for every location, Hicks’ hope is that using it for sections of outage-prone lines that serve large numbers of members will improve reliability for members in other parts of the system as well. After all, if linemen don’t have to respond to those outages first, they can get to other members faster. “We don’t know what the future holds for this technology,” Hicks says. “For the time being, we are viewing tree wire as a potential tool for improving reliability where other options aren’t feasible.”