Background
In 1963, Arkansas Electric Cooperative Corporation (AECC) completed the Thomas B. Fitzhugh Generating Station at Ozark. At the time, the plant—the first built by a co-op in Arkansas—provided 50 MW of natural gas- and oil-based electricity generation.
In 2003, the plant was expanded to 171 MW. Eventually, this led to the need to upgrade transmission lines delivering power from the plant to users, including the 161-kV Fitzhugh-SPA (Southwestern Power Administration) line.
Justification for Conductor Selection
This line had a unique challenge for AECC. An ACSR Dove conductor was installed on most
of the line, but to meet clearance requirements set by the Army Corps of Engineers, an ACSR Brahma conductor, which has more steel than aluminum, was used for the section of the line that crosses the Arkansas River.
When it was time to upgrade the line’s capacity, AECC had trouble finding a conductor that could maintain the clearances over the river and carry the additional power that was needed. As a result, by 2012, that section was acting as a fuse on the line. To solve the issue, AECC decided to use 3M’s ACCR 557-T23 (283 mm²) on the river crossing (Figure 11). Using 3M’s advanced conductor allowed AECC to continue to meet the clearance requirements using the existing structures. In addition, there was a large enough capacity increase to meet current demand and forecasted increases, while keeping project costs to a minimum.
Figure 11. A 161-kV transmission line that crosses the Arkansas River