American Transmission Systems Inc. (ATSI) plans to install nearly 50 miles of new 345-kV transmission line in northwest Ohio to mitigate the effects of generation retirements and to address bulk transmission system contingencies.
The FirstEnergy (NYSE:FE) subsidiary on Sept. 26 filed a letter of notification (LON) with the Ohio Power Siting Board (OPSB) proposing to install 48 miles of new line on the open arm of the existing Allen Junction-Midway-Lemoyne line. That line runs from the existing Allen station through the Fulton, Midway and Dowling substations to an area near the Troy station and finally to the Lemoyne station.
The company’s 345-kV and 138-kV system in the greater Toledo area and northwest Ohio currently faces capacity shortage, thermal ratings constraints and low voltages on the electric transmission system, ATSI said.
“The reduction in power plant real and reactive power output at the Bayshore plant accelerated this transmission line project to be an immediate need for 2015 summer peak loading conditions,” the company said in the LON. “When compared to other alternatives, the proposed project is the best option to resolve thermal overloads and voltage violations, based on the existing infrastructure, and will strengthen the system for years to come.”
The area south and west of Toledo has limited 345-kV extra high-voltage infrastructure, the company said. ATSI’s existing 345-kV system has a single 24-mile, 345-kV circuit between the Lemoyne and Midway substations, and a single, 24-mile 345-kV circuit between the Midway and Allen Junction substations. From the Allen Junction substation, there is a single, 50-mile 345-kV tie-line heading north to Michigan.
“An electrical fault anywhere along this long point-to-point 345-kV network places stress on the electrical system,” ATSI said. “There is approximately 98 miles of exposure on this overhead 345-kV system, where a single 345-kV circuit could be rendered out-of-service, either momentarily, or for an extended period of time (possibly weeks or months for tornado damage).”
The company aims to have the project in service by June 1, 2015.
Because an open arm does not exist between the Troy and Lemoyne substations, as the position that would be used for the proposed project is currently occupied by the Lemoyne-Troy 345-kV line, the Lemoyne-Troy line will be moved to new structures.
When the proposed project is installed, the existing and new construction will be configured into the Lemoyne-Troy Energy 345-kV, Allen Junction-Fulton-Dowling-Lemoyne 345-kV (bypassing the Midway station) and the Allen Junction-Midway-Lemoyne 345-kV transmission lines (bypassing the Fulton and Dowling stations).
In addition to the installation of the transmission line conductors in the open arm position on the steel lattice towers, the company will install three separate locations of additional transmission structures, according to the LON.
No new right of way needs to be acquired for the project, the company said.
ATSI plans to file an LON “in the near future” for the new Dowling substation (Docket No. 13-0224-EL-BLN).