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Overhead Transmission

From 69kV wood pole lines to 500kV lattice tower transmission lines, Wilson's high voltage overhead expertise is respected throughout the West. Whether your project requirements include hot-work, environmentally sensitive crossings, or other challenging site conditions, Wilson brings a dedication and commitment to quality and safety that is unsurpassed in the industry. From working on energized lines to utilizing helicopters to pull sock lines, Wilson is known for our ability to bring even the most complex projects to safe, successful completion, on time, and within budget.




Projects Examples

Wind Energy Transmission Texas 345kV Transmission Line, TX

At the request of Isolux Corsan USA, Wilson was introduced to this overhead transmission line installation project in July 2013, in an effort to expedite the project schedule.  Our original scope of work consisted of stringing 30 miles of single circuit twin bundle conductor, optical ground wire (OPGW) fiber, and overhead static wire (OHSW) located in segment 5A of the project.  Wilson’s exceptional performance and safety record on the project then led to three more contracts being awarded, totaling an additional 33.4 miles of single circuit twin bundle conductor, 64.2 miles of OPGW fiber, and 25.6 miles of OHSW throughout segments 3, 6 and 7 of the project. 

Challenges arose toward the end of the project as a result of inclement weather and additional tower modifications that were required to be installed in short notice.  Wilson crews adapted to the change in scope and schedule, working through the winter holiday season.  Battling freezing rain, snow and wind to overcome the challenges, the final segments were completed and the line energized on January 29, 2014.

Isolux HSE Manager:
"In my experience, Wilson construction brought a team of professional employees dedicated to Safety before production. The work environment in West Texas brought wind, ice and dust to bear on our high energy/high risk operations. Wilson Construction managed this risk and adapted to the environment keeping safety the first value as expected. The work we have observed has been exemplary regarding HSE project planning, employee training, equipment inspection, aerial operations, boom trucks and cranes. Wilson Construction has executed ~70,000 man hours on our project without any work related injuries."

NERC Alert Structure Replacement Project, OK, AR, MO

Spanning multiple states—Oklahoma, Arkansas and Missouri—this procure/construct project consisted of complete removal and replacement of 139 structures along 400 miles of Southwest Power Administration’s (SWPA) 161kV powerlines.  The project required attention to detail and coordination by the Wilson team.

The scope of the work required coordinating with multiple area outage office managers and meticulously planning logistics for this multi-state project as well as working with several local unions.  Wilson supplied project management staff, QA/QC, environmental oversight, safety management, and equipment maintenance services.  Crews removed the existing structures, including poles, cross-arms, braces, and associated materials, and replaced them with new structures and materials.  The existing conductor, overhead ground wire (OHGW), and optical ground wire (OPGW) suspension units were reused, but insulators were all replaced.    Wilson crews also removed 8’ of sag from 2 separate dead-end spans and installed all access roads, culverts and gates, in addition to clearing trees.

In terms of challenges, Wilson was responsible for procurement, transportation and management of all project materials—which required keeping thorough inventory control records, as well as storage, security, and transportation of all Wilson-provided materials across 400 miles of right-of-way.  Scheduling outages could have presented a problem, but Wilson worked closely with SWPA area management in order to seamlessly schedule outages on the dozen or so line sections, while providing flexibility to our customer’s load needs.

As a direct result of our focused and detailed work ethic, Wilson succeeded in completing the project safely and to client specifications.

Grand Coulee 500kV Cable Replacement Project, WA

Wilson removed two single circuit lattice steel 500kV transmission lines, 1.1 miles each, and replaced them with three double circuit lattice steel 500kV transmission lines. Environmental elements of the project included avoidance and protection of environmental resources, timing restrictions, a Storm Water Pollution Prevention Plan, Spill Prevention and Control Plan, Dust Control Plan, and providing an Erosion and Sediment Control Lead (ESC Lead). Work also included brush removal for access roads, retaining walls and tower pad construction. Wilson designed, built, and removed a temporary access road ramp behind Coulee City Hall to access the site.  Crews rappelled the face of the dam in order to complete work attaching dead-end assemblies to the face. Several design challenges were encountered towards the end of the project requiring crews to work closely with engineers and resolve the issues while meeting scheduled power outage dates.


Cable removal work includes removal of cable oil, tanks, and six sets of three 525kV cables that travel approximately 6,400 feet through two tunnels located within the dam. This work required development of custom machinery to work within the tunnels in order to remove cable safely and efficiently. This portion of work is scheduled to be complete by mid-December 2013.


Albany - Eugene 115kV Transmission Line, OR

Wilson Construction rebuilt 31 miles of single circuit 115kV transmission line in Albany, OR for Bonneville Power Administration.  There were 370 wood pole transmission structures completed throughout the course of the project combined with 500,000 linear feet of conductor. This project was parallel to an active railroad, and encumbered by sensitive areas. Wilson developed a unique material delivery systems that minimized our foot print on the land, and increased our crew safety. 

O’Banion – Elverta – Natomas 230kV Transmission Line, CA

Wilson Construction constructed 34 miles of double circuit 230kV transmission line in Sacramento, CA for Western Area Power Administration.  There were 171 monopole structures with davit arm design on pier foundations.  Foundation crews poured over 12,000 cubic yards of concrete and installed 171 pier foundations in less than four months.  The conductor was 954 vertical bundle-2 with 2 OPGW shield wires.  Conductor and OPGW was installed during the rainy season in the Sacramento Valley and was completed utilizing over 2,000 heavy crane mats and two company owned MD500E helicopters.  Project also consisted of removing five miles of existing conductor and lattice towers and installing 18 embankments consisting of 23,000 cubic yards of select fill.  This high profile project was extremely environmentally sensitive and was completed without a single environmental infraction resulting in a work stoppage.




McNary – John Day 500kV Transmission Line - Phase I and II, WA


Wilson Construction Crews completed the 79 Mile, McNary to John-Day 500kV transmission line for Bonneville Power Administration (BPA) in the fall of 2011.

Work consisted of construction of the McNary – John Day No. 1 500kV lattice steel transmission line and relocation of the Rock Creek – John Day 500kV lattice steel, single circuit transmission line.  The transmission line starts in Washington across the Columbia River from Umatilla, OR.  It proceeds west for about 70 miles along the Columbia River in Washington. 


The 79 mile transmission line consists of 369 steel lattice towers and footings, triple bundle 1590 ACSR Deschutes conductor, and 72 count ADSS fiber optic cables.  The project included access road construction, avoidance and protection of environmental resources, and timing restrictions.  Due to steep mountain terrain for some 30 miles of the transmission line, helicopters were used extensively. 



McNary – John Day 500kV Transmission Line - Phase III, WA

This project concluded the final segment of construction on the McNary – John Day No. 1 500kV lattice steel transmission line, as well as the reconstruction of the River Crossing Corridor.  The crossing of the Columbia River included the installation of a 315’ tall 250,000lb lattice tower to maintain appropriate clearance over the water.  The work realigned the existing three-line corridor to accommodate the new McNary-John Day No. 1 500kV line.

The line corridor crossing the Columbia River near McNary Dam consisted of three lines of towers: 

  • the de-energized 69kV Benton County PUD double circuit transmission line;

  • the 230kV BPA McNary-Franklin No. 2 and the 115kV BPA McNary-Badger Canyon No. 1 double circuit transmission line;

  • and, the 230kV BPA McNary-Horse Heaven No. 1 and 345kV BPA McNary-Ross No. 1 double circuit transmission line. 


Sedro Woolley -- Horse Ranch 230kV Transmission Line, WA

The Sedro Woolley-Horse Ranch 230kV project was a design-build contract for nearly 40 miles of 230kV double bundle single circuit installation stretching from Sedro Woolley, WA to Snohomish, WA. Wilson Construction Company utilized the services of POWER Engineers for the development of the project design and SWP Environmental Services Co. to develop and implement the Storm Water Pollution Prevention Plan.

The design required over 300 tubular steel poles, using both concrete pier foundations and direct imbed installations. The line traveled through a mix of suburban and rural properties with several limited access locations, including one structure that was airlifted into place with tight FAA overview. 

As luck would have it, the spring and summer of 2010 was one of the wettest on record for this Western Washington location. Wilson Construction was able to overcome this obstacle and successfully delivered the project according to the planned energization date.



Swan Lake – Lake Tyee, AK

This 138 kV transmission line crosses the Tongass National Forest and is located in Southeast Alaska near Ketchikan. The Intertie extends generally north approximately 57.4 miles from Ketchikan Public Utilities to the Lake Tyee hydroelectric project, where Wrangell Light and Power and Petersburg Municipal Power and Light systems are connected.  Nearly 47 miles of the right-of-way lie on National Forest System land administered by the Forest Service.  The remaining land is State of Alaska owned.   The Right-of-Way is impossible to traverse by means other than helicopter.  Wilson crews worked from  a "base camp" barge and were flown to tower locations by Wilson's helicopters. 

Foundations began in the spring of 2004 utilizing Crux Subsurface to install micropile foundations.  Unfortunately, funding from various state and federal agencies didn’t keep up with construction and the foundation operation was halted with approximately 70% of the foundations completed.

All funding was finally in place in late 2007 and we remobilized Crux in the spring of 2008 to complete the foundations and guy anchors.

Wilson mobilized in the winter of 2009 to receive the steel structures and other materials required to finish the line installation.  Erickson Air Crane was subcontracted to fly the structures, conductor reel stands and conductor reels in June of 2009.  252 structures and all stands and conductor were flown and placed or installed in a record 9 days.  After the structures were set and the conductor was placed, the stringing operation began.  Conductor pullers and tensioners were purchased from TESMEC in Italy, shipped to Canby and then modified by Wilson mechanics to “modularize” the equipment into smaller components whereas a medium lift helicopter could pick and fly the individual components. The project was completed safely, under budget and ahead of schedule. 



"The Southeast Alaska Power Agency is thrilled that Wilson completed construction of this very difficult project six weeks ahead of schedule.  We are very pleased with Wilson's dedication and professionalism.  They took on a very difficult and challenging project and worked with us, as the owner, to find ways to overcome delays caused by significant funding hurdles.  This project was completed ahead of schedule and under budget which has exceeded my most optimistic expectations.  Wilson and their subcontractors performed superbly!"

-- Dave Carlson, CEO Southeast Alaska Power Agency

Buck – Julian Hinds 230kV Transmssion Line, CA 

In mid-January 2009, Wilson Construction was awarded the Buck-Julian Hinds 230kV project for Nextera Energy.  Crews began working on this year-long project in late February 2009.  The 230kV transmission line extends from the Blythe Energy Plant west to the Julian Hinds Pumping Station.  The line is 67 miles in length and is comprised of 286 concrete structures and 143 tubular steel structures with some of the concrete structures weighing over 80,000lbs.  The design is primarily single pole with davit arms, but there are some H-Frames, and 3-Pole structures.  There are 54 pier foundations on the project with the largest being 12’ x 44’.  Wilson self performed the pier foundations utilizing our Watson 3110 and LoDril.  The conductor consists of 3-bundle 1033.5 “Curlew” ACSR and an overhead optical ground wire. 

The line was proposed to the California Energy Commission (CEC) in order to transmit power from the Blythe Energy Plant to the Southern California Edison energy grid which could be connected at the Julian Hinds Pumping Station.  This particular transmission line project is extremely unique because it is a non utility regulated project.   This means the project falls under different guidelines and inspection procedures, which are more stringent.  Complicating the project even more is the fact that the entire project lies in prime desert tortoise habitat. 

Despite these challenges and battling high temperatures (120 degrees +) all summer, crews have stayed ahead of schedule and have done so without incident.  Currently, crews are pulling wire and are expected to complete construction at the end of January 2010. 

Ebey Slough Transmission Line Rebuild Project, WA 

Wilson Construction Company was retained by Puget Sound Energy to replace two single-circuit transmission lines located near Ebey Slough, Washington with one double-circuit transmission line.  The existing line, constructed as separate 115kV and 230kV circuits on parallel wood pole H-frames, serves as an important regional demand for energy and has been badly damaged over the years.  The new line consists of 15 steel monopoles designed to carry the two existing parallel transmission circuits.  Wilson‘s design/build team consisted of Power Engineers (line and conventional foundation design), Crux Subsurface, Inc (micropile foundation design) and SWP Environmental Services Co (environmental permitting, inspection and monitoring).  Wilson crews faced many challenges on this two mile project, as the right of way was located in a large emergent wetland which is tidally influenced.  A majority of the work was performed using large marsh buggies or helicopters to support crews.  


Hayden –  Roberts 345kV Transmission Line, OH

Wilson crews completed the Hayden Roberts 345kV Transmission Line Project for American Electric Power Service Corp on April 13, 2009.  The work consisted of constructing 6 miles of 2 bundle conductor and one optical ground wire for the second circuit on an existing 345kV Transmission Line including installation of two 56’ steel poles located near Hilliard, Ohio.  Construction began on March 23rd and the crews worked 7 days and week, sun up to sun down to finish within the tight outage timeline. 


Hoover Mead –  Mead #6 and #8 230kV Transmission Line, NV

Wilson Construction Co. recently completed the Hoover-Mead #6 and Hoover-Mead #8 230kV Transmission Line Jumper Clamp Reinforcement Project.  This project was sent out by the Department of Energy Western Area Power Administration as an emergency project needing immediate attention.  The jumpers were wearing through and falling open which potentially could have caused power outages to customers.

The principal components of work included drilling holes into the existing jumper termination plates and installing Government-furnished reinforcement plates and hardware to the jumper connections along two separate three-phase 230kV transmission lines.  The repairs required to the Hoover - Mead 230kV transmission lines 6 and 8 were within four and five miles of the Hoover Dam Switchyard #1, respectively.  The transmission lines crossed rugged desert terrain; surface access was limited to very primitive roads at only a few of the structures.  Due to the difficult access, Wilson helicopters were used extensively to complete the work. 


Bailey – Pastoria 230kV Transmission Line Reconductor, CA

This project called for the replacement of 76.76 miles (501 spans) of existing 605 kcmil ACSR conductors with new 666.6 kcmil ACSS/TW conductors.

In addition, Wilson Construction Company raised 14 towers as well as converted 30 towers from suspension to dead end configurations. 28 miles of the work on this project was located within the Angeles National Forest boundaries, as well as several miles that traverse through the Tejon Ranch.  Our in-house helicopters were used throughout the construction process to minimize the environmental impact along the right-of-way. 


Swan Valley – Teton No. 1 and 2 115kV Lines, WY

This project covers the modification to the double-circuit portion of the Swan Valley-Teton No. 1 and 2 115kV lines. To gain more clearance between the phases, the upper pedestal, cage and crossarms of two lattice steel towers were replaced along with one complete lattice steel tower. One span of conductor was replaced and groundwire removed from two spans. Insulators were added to extend the existing dead-end hardware assemblies.

This project was located at the top of Teton Pass, in the Teton National Forest, Wyoming, at approximately 9,000 feet elevation. Wilson’s helicopter carried equipment and tools to the work areas and supplied hardware and tools to the linemen in the towers located in areas with no vehicular access.  






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