June 11, 2025 Delivering 765kV Construction and EPC Project Success in Ohio
Working together, MYR Energy Services and The L.E. Myers Co. upgrade Marysville substation and construct 765kV double dead-end transmission tower
Utilities around the country are faced with many electrical system needs including interconnecting clean energy projects such as solar fields to their power grid. MYR Group companies are delivering these projects successfully in many parts of the U.S., including the Midwest.
MYR Group subsidiary MYR Energy Services (MYRE) recently completed an engineer-procure-construct (EPC) project in Marysville, Ohio to serve this purpose for a new solar development.
MYRE led the project which included upgrading a bay of the Marysville substation, erecting two new transmission monopoles and stringing 345kV wire from the substation to the point of interconnect, and constructing a 765kV dead-end lattice tower to raise the existing transmission line to accommodate the route for the 345kV line.
They brought in fellow subsidiary The L.E. Myers Co. (L.E. Myers), which operates across the Midwest, to perform the transmission line construction due to their extensive experience and familiarity with the customer’s systems.
As the EPC manager, MYRE led the project and worked with an engineering partner to design and engineer all three facets of the work, ordered the materials, and L.E. Myers performed the transmission and substation construction.
Through collaboration, they successfully met the customer’s project requirements and managed challenges effectively.
“I think anytime you can keep scopes of work under the MYR Group umbrella it is advantageous because we can work better and more transparently together,” MYRE Operations Manager Harrison Casey said.
Team Manages Unique 765kV Scope Addition Despite Supply Chain Hurdles
Originally the Marysville EPC project didn’t call for any 765kV transmission work, but when the need arose, MYRE and L.E. Myers found the necessary solutions for this uncommon transmission voltage.
While the project was in the engineering phase, a route adjustment by the solar developer prompted the additional need for a 765kV double dead-end lattice tower to raise the height of existing transmission line. The existing line was too low to provide enough clearance for the 345kV interconnect line to run beneath it.
Director of Engineering – EPC Tracey DeKraker joined MYRE as an engineering manager during the engineering phase as the 765kV scope was being added. She explained that it is harder to design and engineer the addition of a tower into an existing transmission line than to design a new section of line. Getting it designed so that the line sag would be correct once the new tower raised the line was a challenge the team worked together to overcome.
The procurement team also faced challenges due to long lead times and material shortages. They overcame this difficulty by finding a tower manufacturer that could produce the specialized lattice tower in time, as long as they ordered well in advance.
L.E. Myers Safely Constructs and Energizes New 765kV Tower
L.E. Myers’ experienced line crews laced, erected, dead-ended the wire on each side of the tower and energized the new 765kV double dead-end tower over the course of 29 days, starting in September 2024.
Currently, working with 765kV is less common in the U.S. – although that may change over the next decade if regional transmission organizations move forward with plans to build new 765kV backbones for the electric grid.
L.E. Myers’ Construction Manager Scott Ross explained that construction of 765kV transmission is also more difficult than lower voltages because the tower must be taller and the components including conductor wire are heavier. New rigging, spreader bar, and slings were acquired for the project due to the length and weight of quad-bundle conductor and the insulators which had 32 bells each.
The tower also had to be laced onsite near the existing, energized line – requiring grounds on all the steel and maintaining the minimum approach distance (MAD) to perform the work safely. A spotter worked to ensure crew members did not encroach on the MAD.
The laced sections had to be carefully arranged on the ground so the crane could lift them when the time came. Once the outage arrived for the existing line, L.E. Myers relied on MYR Group’s fleet to provide the 350-ton crane needed to erect the steel lattice tower. The bridge section alone was a 36,000 lb. lift that had to be raised to top the 125-foot tower.
Once the tower was fully erected, the L.E. Myers crews installed stringing blocks on the tower and transferred the wire into dead-end positions. They put rigging on to catch the wires once they were cut from the middle and formed the 8 dead-end assemblies (four in each direction, per phase). Lastly, they installed the jumper assemblies and insulators for each of the three phases.
Pre-planning was essential to safely performing this work. During pre-planning, the team examined the line sags, calculated the weight of everything the crane would have to lift (including picking up pieces of the tower) and determined the proper tooling, rigging and equipment they would need to safely complete each step.
That planning, combined with excellent communication, experience working with multi-bundle wire, and all the safety processes and procedures in place during the construction phase, enabled them to successfully complete the 765kV work safely, without any recordable incidents or first aids.
“Their safety record has been impeccable, they are great at doing ‘all stop work,’ and always doing good catches,” MYRE Project Manager Jacob Tulachka said of working with L.E. Myers.
Upgrading the Substation and Adding the Interconnect Line
The Marysville substation is large, with many transmission lines coming into it. For the solar developer to tie-in at this station, the utility needed upgrades to a 345kV bay in the substation where the connecting transmission line would run. They also needed a short stretch of 345kV transmission added connecting the substation out to the point of interconnect.
L.E. Myers removed substation equipment in the existing bay that needed to be replaced and installed the new circuit breaker, CTs, CCVTs, lightning arresters, a new motor operated switch, all associated control cabling, and two new control panels in the existing control house.
They also performed the 345kV transmission construction which consisted of two new monopoles and new 345kV conductor from the substation to where the solar developer’s 345kV transmission line will tie-in in the coming months.
L.E. Myers safely completed this work in November 2024.
Project Details: Marysville IPP 765kV Tower and Other Upgrades