By Lisa Meiman
On July 17, a powerful microburst with 80 mile-per-hour winds uprooted trees, damaged multiple high-voltage transmission lines and flattened a mobile home in the Salt River Pima-Maricopa Indian Community north of Phoenix, Arizona.
WAPA, Arizona Public Service and Salt River Project all suffered significant transmission line damage along a shared corridor when the storm downed the lines across State Highway 87. More than 40,000 customers lost power locally and in the greater Phoenix area, in some cases for days.
Desert Southwest crews and the region’s helicopter arrived the next day to assess the scene. Their first objectives were to determine the extent of the damage, stabilize undamaged structures and remove debris, particularly from the closed highway.
“Certain structures were on the ground; several structures were still standing and badly damaged. You had to clean up and complete demolition as safely as you can,” said Transmission Lines and Substation Maintenance Manager Mike Simonton. “It’s a difficult task. Things can go wrong because there are thousands of pounds of tension on the structures, and the structures were not designed to bend the way many of them had. Our crews had to take the structure down in a manner that is not ideal.”
In total, 14 steel lattice structures over two miles were damaged beyond repair along the Pinnacle Peak-to-Rogers 230-kilovolt, double-circuit line. Several structures had already crumpled to the ground while others began buckling when conductors were cut, releasing the tension that had held those structures in place.
“Several of WAPA’s regions, customers and neighboring utilities contacted us to offer assistance. We were very appreciative of those offers and the strong partnerships we have with them,” said Senior Vice President and Desert Southwest Regional Manager Jack Murray. “We are also very thankful for the outstanding work by our linemen, dispatchers, engineers and staff that are living up to our core value of ‘Serving like your lights depend on it.'”
On July 19, Murray declared the event an emergency due to the criticality of the line for safety and reliability.
“When an emergency is declared, WAPA has agreed-upon procedures in place for Lands and Environment that enable efforts to move quickly through the review process. This is extremely important for immediate response to emergency conditions,” said Simonton.
Clean up, restore, rebuild
While line crews worked on securing sites and clearing conductors and debris, it was all hands on deck for engineers, operators, environmental protection specialists, realty specialists and others in DSW and Headquarters to identify a way forward.
“This recovery required a group effort. In most emergencies, it is only a small group of people that we use: lands, environmental and maintenance,” said Transmission Lines Maintenance Supervisor Abel Betancourt. “On this project, we had to include Budget, Finance, Procurement, Construction and also Headquarters and the outside regions as well for materials and for people. It was a large-scale effort.”
Rebuilding a large steel transmission line takes a significant amount of time to design and procure materials. Not a good short-term solution.
“The goal is to restore as much service as you can as quickly as you can. We needed steel structures, but it is not common practice for WAPA or other utilities to have steel structures lying around,” said Simonton. “Doing a temporary repair for a single circuit can restore 50% of the capacity in a relatively short amount of time rather than waiting.”
The DSW team decided to build a temporary line on 18 wood structures that would carry one of the circuits. The second circuit would be brought into service once the permanent rebuild with steel monopoles is complete, which is expected in early 2024.
With a plan in place, engineers worked with Environment to avoid culturally sensitive sites, particularly close to the Community, and other employees scoured Maximo for a list of available materials that could be shipped to DSW on short notice.
“Thanks to Western Maintenance Managers Council, we were able to receive and mobilize materials, equipment and personnel within five days of storm,” said Betancourt. “About 98-99% of the material we used came from Rocky Mountain and Upper Great Plains. This storm brought out the ‘Team WAPA’ spirit.”
Extra material was transported from RM and UGP by July 22, and the rental equipment, barricades, cultural site markers and line materials were staged for linemen to begin building the temporary line July 23.
The goal was to energize the temporary line in three weeks. It was built in two, yet the work was not easy for the joint DSW and RM crews.
“They encountered heat, humidity, weather and highway traffic during business hours. We typically work in remote areas so we don’t have to deal with busy traffic and rush hour. And, of course, we had other utilities and contractors out there doing the same thing as us,” shared Betancourt. “With the amount of line down, we had additional resources like a scrapyard company removing debris and barricade services. And then all the residents there were coming up and asking questions.”
Adding to the challenge was a monsoon that dropped about four inches of rain July 24 and 25 on the Community, an area that receives an average of eight inches of rain annually. The microburst had delivered another inch and a half of rain July 17.
“Rain delayed helicopter services, and the surrounding agricultural lands were muddy or filled with two-to-three feet of water,” said Simonton. “Things got pretty sloppy in certain areas, a big soupy mess of mud. The terrain, in general, was difficult. It was a lot of soft dirt and gravel.”
Organizing the permanent line rebuild was another effort, no less important than the temporary build. Engineers, Procurement specialists and employees from Budget and Finance worked together to design and complete a procurement package for new steel monopoles.
“This is a big project. It is not a cheap or easy fix. Some of the materials, like steel poles and conductors, have long lead times right now,” said Supervisory Civil Engineer Michael Baird. “The project is going through 10-year plan process and will be voted on by the Parker-Davis customers for funding in December.”
Weather tests crews, dispatchers
It was an active monsoon season in the Southwest, temporarily alleviating the most severe impacts of drought, but the precipitation comes with its own costs.
“In the 30 some years I have been here, I do not remember a summer where we have had the number of interruptions we have had this summer in Phoenix dispatch,” said Manager of Phoenix Operations Center Dan DeGracie.
“This is the most repair work we have ever seen,” added Betancourt. “The guys have worked seven straight weeks. We worked three weeks on this project. On the day we completed it, that night we had power down in Yuma and then Parker, Arizona, a couple days from one another. It just snowballed. It has been a nonstop process.”
“Throughout this emergency response, I’ve been extremely impressed with the collaboration and teamwork shown by everyone across WAPA, DSW and Abel’s and Mike [Baird]’s leadership,” said Simonton. “We continue to be grateful for all the support provided from everyone as we collectively meet this challenge. Thank you to all involved, especially the crews led by Terry Kugler working long hours in the heat making it happen. Pending mutual consent, I urge everyone to hug a lineman!”
Note: Meiman was a public affairs specialist.
Last modified on September 12th, 2023