September 8, 2021

Five-hundred kilovolt (kV) transformers are very large, very heavy and not easy to maneuver. When the first unit was recently delivered to Mon Power’s Flint Run substation construction site, it marked a major milestone in the project – especially considering the challenging destination.

​As part of our Energizing the Future initiative, the Flint Run substation is being constructed near Clarksburg, W.Va., to reinforce the regional transmission system and enhance local service reliability. The terrain in this area is rugged, with steep hills covered by dense forests. In all, 95 acres of land was acquired for this project.

“Flint Run is the largest Mon Power substation project in many years. Just constructing the pad for the new substation, which covers seven acres, required moving more than 800,000 cubic yards of earth,” said Project Manager Les Johns.

Getting the nearly 250-ton transformer up to the hilltop substation pad required a closely coordinated effort, according to Les. The access road is steep and includes several sharp bends – difficult maneuvering for the special multi-axle, flatbed transport rig used in the move. With patience, skill and helpful pushing from a large bulldozer, crews navigated the hill to successfully deliver the transformer. A second unit is expected to arrive at the site later this month.

Con​​​necting to the Regional Grid

When completed, Flint Run will tap into the nearby Belmont-Harrison 500-kV transmission line and, through a pair of newly constructed 138-kV lines, connect to the Waldo Run substation, which was added to the transmission system in 2015.

Construction on the Flint Run project started with tree clearing in October 2019. From the ridgetop site of the new substation, a right-of-way was cleared across a valley to the Belmont-Harrison line about half a mile north. To the south, the right-of-way initially follows the ridge, then mostly skips hilltop to hilltop to Waldo Run, which is 3.5 miles away. Roads had to be built to access the new substation site and dozens of steel monopole tower ​locations, with a significant amount of additional earth moving required to stabilize several more hillsides.

Major earthwork began in March 2020 and the new substation pad was completed by mid-December. Above-grade work on the new substation’s facilities is now underway. Meanwhile, at Waldo Run, breakers and other equipment have been added for the new 138-kV lines.

“Construction of overhead transmission lines is scheduled for completion by October,” Les said. “We plan to energize the new lines and the Flint Run substation in November.”

After traversing more than a mile of hilly ridge-top access road, the transformer approaches its new home at the Flint Run substation near Clarksburg, W.Va.

The transformer will be mounted on this foundation pad inside the seven-acre substation enclosure.