PEC will rebuild and upgrade the existing 7.6-mile 138 kV transmission line that connects the Marshall Ford substation to the Trading Post substation and Marshall Ford substation to Paleface substation. These substations have shared lines and structures for 3.6 miles in Travis County. Upgrades are scheduled to begin in the fall of 2022 and are estimated to be completed by spring of 2023.
The purpose of this project is to upgrade the transmission line to meet the structure requirements outlined by the National Electrical Safety Code and increase the capacity of the transmission line. The upgrade includes replacing 3.6 miles of conductor supported by existing PEC’s structures from Marshall Ford substation to Long Wood Avenue and replacing structures and conductor along 4 miles of single circuit transmission line from Long Wood Avenue to the Trading Post substation.
The existing shield wire, which protects the transmission lines from lightning, will also be replaced with an optical ground wire to enable improved relay coordination and supervisory control of substations. The existing single-circuit structures will be replaced with new steel monopoles that are typically 85 to 120 feet tall and have ground line diameters of approximately 5 to 10 feet. Some large-angle poles will have ground-line diameters of up to 12 feet that can be up to 120 feet above ground and are generally used when the line shifts in direction.
The new larger conductors will increase the capacity of the transmission system serving PEC members and other electric consumers in Central Texas. This project will help meet the area’s growing demand for electrical power, improve system reliability, and reduce current ongoing maintenance costs.