Field crews restore power following severe wind storms in the South.
Tornadoes crumpled up Entergy's lattice towers like tin foil during a recent severe weather event in the South. Unlike other tornadoes, which touch a small part of a power line, and then hit an area far away, this storm touched the line and rode for miles.
Strong winds knocked down 53 500-kV towers in the first round of the storm. A few days later, the area was hit with two more severe weather events that ripped down 115-kV, 230-kV and 500-kV transmission lines throughout Entergy's service territory including Arkansas, Mississippi and Louisiana.
The damage to Entergy's transmission system was severe, particularly in Mississippi, where nearly 38,000 out of 435,000 customers were without power. The deadly tornadoes damaged 170 poles, 80 transformers, 115 crossarms and more than 700 spans of conductor in Mississippi.
Nearby in Louisiana, nearly 55,000 customers lost power in a severe storm that damaged about 200 poles, more than 500 spans of wire, 150 transformers and more than 200 cross-arms. More than 625 workers, including 325 linemen, worked to restore power to the northern part of Louisiana following the storm.
Arkansas was also hard hit, with more than 500 poles and 800 spans of conductors in need of replacement following a string of severe weather events in late April. Within a two-week time frame, four major storms hit the state, knocking out power to just under 88,000 customers.
While Texas also experienced severe weather, it wasn't as hard hit as the other regions, making it possible for the company to dispatch some of its linemen to nearby states for assistance. By working alongside its sister crews, the Texas linemen were able to help the Entergy crews restore power and begin the long process of repairing and rebuilding the transmission system.
Fortunately, Entergy already had resources in place before strong winds ever blew through its service territory. Twice a year, the utility conducts a mock storm drill to test the reaction of its field crews and ensure it has all of its contractors lined up and ready to spring into action.
During these preplanned drills, the field crews and management team re-evaluate the status and location of all their materials and then devise a plan on how to transport the equipment to the damaged areas.
For example, in the recent storm, Entergy knew that some of the equipment was located off-site and had to be moved to a new location. Compounding the problem, one of the major arteries through Arkansas was closed down. As a result, Entergy had to reroute materials through the northern part of the state to reconstruct the system in the affected areas including Lonoke County, Hot Springs and around West Memphis.
Entergy also had to work with crews from a variety of different contractors and neighboring utilities. To ensure that everyone was on the same page, the company issued each one of the managers a storm binder that included a list of necessary tools and equipment, machine inspection sheets, orientation forms and contact lists. It also had information on eyewash stations, First Aid kits, incident reporting, personal protective equipment and proper cell phone use.
When working with contractors, it often can be a challenge to ensure that all the workers know the utility's safety rules and regulations. Since Entergy had worked with many of these companies before, however, they were already familiar with their expectations and guidelines. Entergy often helps other utilities with storm restoration, and as such, it had many companies come to its assistance during this particular string of storms. Companies that assisted with the transmission restoration included Irby Construction, Sun Electric, Koontz Electric, and Oklahoma Gas and Electric.
Once the severe thunderstorms and tornadoes actually hit the region, Entergy then relied on helicopters to patrol the damaged lines. In Arkansas, Entergy didn't call out any field employees until there was no danger of anyone getting hurt. The utility's first priority was to make sure no workers were in harm's way.
While the company put people on the ground in the damage areas, it used helicopters to get a bird's eye view of the damage. A lot of the utility's infrastructure is located in rural and remote locations, which made it necessary to use helicopters to gain a visual picture of the destroyed and damaged infrastructure.
Entergy teamed up with Aerial Patrol Inc. out of Little Rock, Arkansas, to patrol the area with helicopters. One of Entergy's field professionals traveled in the cockpit with the pilot. This person took notes and snapped photos as the helicopter patrolled the lines. Entergy then had a better idea of where the restoration needed to take place.
After the aerial patrol, the engineering group studied the photos, assessed the damage to the structures, and devised the best way to reconstruct the damaged towers.
While most of the 115-kV and 230-kV poles were constructed of wood, the towers on the 500-kV line were made from lattice steel. To prevent these structures from buckling in high winds, Entergy is replacing them with tubular steel towers from Valmont Industries. This new configuration is less labor intensive and less complex for the linemen to assemble and install in the field.
Entergy employs Air2 and Erickson Air-Crane Inc. to use helicopters to set new poles and rebuild structures to replace the damaged infrastructure. With hurricane season rapidly approaching, the utility is working to get everything back to normal as soon as possible.
To ensure that no one was without power while rebuilding its infrastructure, Entergy rerouted the power. About 320 linemen worked together from these companies to rebuild the system.
Managing such a large crew of Entergy and contractor linemen can present a challenge. To keep its field workforce injury-free, Entergy managers offered several tailboard sessions. During these meetings, they pulled everyone together in small groups to discuss hazards such as dehydration and heat stress. In addition, they stressed the importance of wearing life jackets in high water and using extra precaution around helicopters.
Also, Entergy advised both its own linemen and the contractor not to be near any downed lines. Many times, lines are down where the linemen can't see them in the darkness. Generally, the utility prefers not to have its linemen work at nighttime unless it's an emergency and a piece of equipment needs to be isolated. In these situations, the linemen can use a personal voltage detector from HD Electric to ensure that they are not in harm's way.
During these tailboard discussions, the linemen discussed heavy machinery and the proper usage of personal protective equipment such as high-visibility vests.
By working together as a team, the Entergy linemen and field professionals from outside contractors and utilities are gradually restoring power and rebuilding the storm-ravaged system. Through preplanning, a focus on safety and teamwork, the region's transmission system soon will be stronger than ever and able to withstand Mother Nature's next round of severe weather events.
John Byard (firstname.lastname@example.org) is the transmission warehouse supervisor with Entergy. He has been with the company since 1983.
Aerial Patrol Inc. www.aerialpatrolinc.com
Erickson-Air Crane Inc. www.ericksonaircrane.com
HD Electric www.hdelectric.com
Irby Construction Co. www.irbyconst.com
Koontz Electric www.koontzelectric.com
Oklahoma Gas and Electric www.oge.com
Sun Electric Services Inc. www.sunelectric.com
Valmont Industries Inc. www.valmont.com