Georgia Power, a subsidiary of Southern Company, one of the nation’s largest electric utilities, has chosen the lightweight, low-sag 3M ACCR overhead conductor to double transmission capacity on a set of lines that cross extensive wetlands near Savannah. The upgrade significantly reduces the need for larger towers or a wider right of way, thus avoiding a range of potential challenges, including construction on environmentally sensitive land.
Based in Atlanta, Southern Company serves more than 4.4 million residential, commercial and industrial customers in four states. Georgia Power is its largest subsidiary.
The upgrade is on a 16.7-mile line linking the Kraft generating plant in Savannah with its McIntosh plant north of the city. The project resolves potential capacity issues by approximately doubling the 230kV double circuits’ line capacity, replacing a conventional steel core conductor with a 3M ACCR 1622 kcmil conductor that is light enough to be accommodated mostly by the existing infrastructure.
After studying a number of options and considering the capacity increases achievable; the costs of structures, construction and permitting, and conductor costs, Georgia Power chose ACCR as the most cost-effective option.Bob Beck, Southern Company Services Senior Transmission Planner, cited three issues that confronted the upgrade project: right-of-way expansion was not feasible, wet terrain made tower construction very expensive and environmentally problematic, and construction outages were limited to light-load periods. “3M ACCR enabled us to use mostly existing towers and to re-conductor with minimal disturbance to the land and no service interruption,” he said. In 2013, the company is completing a similar project with 3M ACCR to further enhance area reliability. 3M ACCR’s composite core is as strong as steel, but lighter, and its coefficient of thermal expansion is half that of steel. Tim Koenig, director of 3M’s High-Capacity Conductor program, notes, “Utilities around the globe are recognizing 3M ACCR as a proven solution to electric transmission constraints that is both cost-effective and applicable to a very broad range of climate conditions and terrain. Most important, it offers a means of quickly making more power available in response to growing demand without the financial and environmental risks associated with enlarging towers or expanding rights of way.”