Safety is the top priority during the construction of any high-voltage power line. For Georgia Transmission Corp. (GTC), safety took on a greater meaning than ever as the cooperative that builds and maintains infrastructure on behalf of Georgia’s electric membership cooperatives (EMCs) undertook construction of a 115-kV line that crossed a pristine salt marsh. This project upped the ante by requiring the project team to consider the safety of the natural environment, motorists along a major East Coast interstate highway, state-protected property and aircraft that aided in innovative construction.

With a thorough planning process, deep involvement with the local EMC, and close collaboration with state and federal regulatory agencies from the Georgia Department of Natural Resources (DNR) to the Army Corps of Engineers, GTC was able to complete a 12.2-mile (19.6-km), 115-kV transmission line on Georgia’s coast to shore up electric reliability and support an ongoing wave of economic development in the region.

System Fortification Needed

The economy of coastal Georgia is growing as more businesses seek to expand their operations, and steady growth at the Port of Savannah is yielding economic dividends for the entire state. Because reliable electric service must be in place to meet the needs of area communities and to attract and nurture continued economic development, GTC and Coastal Electric Cooperative, the local EMC, identified the need for an additional electric transmission line to reinforce reliability on a radial transmission system and help to prevent outages in the region.

In 2007, GTC released a project for a transmission line that would connect the Burnt Church Road Substation in Bryan County, Georgia, to the Tradeport Industrial Park Substation in Liberty County, Georgia. In addition, Coastal Electric Cooperative would build accompanying distribution lines on the new transmission infrastructure to support distribution load shifting during substation outages.

The existing system serving the region includes a northern tier of substations and a southern tier of substations. These substations use radial lines connecting one another to a single point of service. If one portion of the line fails, power is lost to the remainder of the regional system. As a result, GTC wanted to connect the northern group of substations with the southern group of substations to create a dual feed.

The new transmission line would reinforce the existing infrastructure in the coastal region, prevent overloads and ensure reliable electric service to Coastal Electric customers, including a major retail distribution center and an aeronautical manufacturing company. In addition to this existing commercial development, planned development and land-use designations promised further use of the already taxed system.

GTC, sa.t marsh, Sikorsky S-64 Skycrane