Preparation, time, care extends Arizona customers’ reliability
|A weathered wooden H-frame structure is taken down and replaced with a single-circuit, steel monopole structure to minimize Western’s environmental footprint on the 69-kilovolt Davis-to-Kingman Tap in northwestern Arizona. (Photo by Jason Groendyk) See more photos at the Flickr Davis-Kingman Tap album.|
by Tiffani DeFore
Many of Western’s maintenance projects are not performed to add capacity to our transmission system, but rather to increase reliability for our customers and for Western’s system.
One of these projects, the 69-kilovolt Davis-Kingman Tap upgrade project near the Nevada border in Arizona, was completed three months ahead of schedule, bringing more reliability to customers receiving power through the line. The project took longer than 10 years to complete because of the extensive work needed for the environmental review, right-of-way access, contracts, scheduled outages and funding.
The upgrade project involved adding new switches at three different taps along the line and replacing wooden H-frame structures with single-circuit steel monopoles. Construction began in October 2012 and finished in February 2014 with the contractor only taking breaks between June and September 2013 to avoid outages during the hot Arizona summer when power demand peaks to cool homes and businesses.
Most of the 27-mile transmission line traverses Bureau of Land Management land, including two mountain passes, to deliver hydropower to three Desert Southwest municipal utilities: Mojave Electric, Southwest Transmission Cooperative and Unisource Energy. Adding the new switches allows Western to isolate problems to a smaller area minimizing impacts in the event of an outage while installing the stronger steel monopoles leaves a smaller environmental footprint and requires less maintenance.
Accommodating for environment, biology
The location of the line posed many design challenges for crews and DSW staff. To meet BLM requirements, Western procured weathering steel structures—brown instead of silver—so the towers would blend in more with the terrain.
The project also presented a number of scheduling challenges. According to DSW Environmental Manager Linda Marianito, “Western needed to plan the implementation of the project to meet construction needs and the seasonal restrictions outlined in the BLM Management Plan.” For example, about four miles of the line passes through the BLM Black Mountains Ecosystem Management Area, which contains crucial habitat for desert bighorn sheep. To prevent impacts to these sheep, Western prohibited construction in this area during the lambing season, which takes place Dec. 1 to May 31.
In addition, Western implemented pre-construction surveys and monitoring throughout the project for other biological resources, including the Sonoran desert tortoise, nesting migratory birds, western burrowing owls and native plants. “We sometimes had up to four [contractor] monitors on-site depending on the time of year, the habitat where construction crews were working and how the crews were dispersed along the line,” said DSW Environmental Planner Johnida Dockens. “The monitors were there to provide environmental awareness to all the crew members and to check for bird nests, tortoises and other biological resources. The monitors reported numerous wildlife observations, but also indicated that the crews had demonstrated an appropriate level of environmental awareness in those situations.”
Replacing the line reduces the future need for maintenance in an area that is challenging to access, given the difficult topography and underlying land management requirements.
Maximizing resources, time
Gathering materials for the line construction took time and resources as well. The idea was to be prepared before construction started. Rick Schuler, a contracting civil engineering technician, made sure the materials were on site six months before construction started. “Every day, for several consecutive weeks, there were a dozen or more trucks showing up to deliver materials,” said Project Manager Jason Groendyk.
Realty specialist Jessica Herndon worked with a local landowner to “borrow” land to create a 5-acre laydown yard to house the materials and stage construction trailers and equipment for nearly two years.
Customer satisfaction drives process, planning
Staff went above and beyond what was required to make sure customers saw as little impact from the project as possible—especially with the time and effort made to go over every detail of the switching procedures and construction activities. The communication and planning of the sequence, timing and duration of each planned outage was critical considering multiple customers and several small, isolated communities depend on this single transmission line to provide reliable electrical service. Groendyk said, “Before the start of demolition and re-construction of each segment of the line, we went through a lessons-learned process to review and improve on processes to minimize the impact to the customer.”
Timing outages was critical to ensure residents and businesses were not left in the dark and required communication with the other utilities to make sure outages generally lasted no more than four hours at a time. “I truly appreciate the support [Western has] given to this matter. What you have contributed would not have happened in the earlier years,” said Bill De Julio of UniSource Energy Services. “The collaborative efforts between UES crews, Brink Construction and Western made this outage the success that it was.”