PPL Electric Utilities on April 10 filed with the Pennsylvania Public Utility Commission a petition for waiver of certain commission regulations governing the review and approval of the siting and construction of high-voltage electric transmission lines, along with a letter of notification to request that the commission approving the siting and construction of a proposed project in Lehigh and Carbon counties in Pennsylvania.
The project involves Phases 2 and 3 of a larger three-phase project in which the transmission lines between the Siegfried, Hauto, and East Palmerton substations are being rebuilt, the company said. The commission approved Phase 1 in July 2013, PPL Electric said, adding that the first phase of the three-phase plan to replace aging transmission lines between the Siegfried, East Palmerton, and Hauto substations addressed the 8.5 miles of the Hauto-Siegfried #1 and Siegfried-East Palmerton #2 138/69-kV circuits, and the Hauto-Siegfried #4 and Siegfried-East Palmerton #1 138/69-kV circuits, from the Siegfried 230-138-69-kV substation until it reached the “split,” which refers to the approximately 6.9-mile section between a point where the existing Siegfried-East Palmerton #1 and #2 138/69-kV Transmission Lines and the existing Siegfried-Hauto #1 and #4 138/69-kV Transmission Lines diverge in Washington Township.
For Phases 2 and 3, it seeks approval to rebuild about 6.9 miles of the existing Siegfried-East Palmerton #1 and #2 138/69-kV Transmission Line and about 15.2 miles of the existing Hauto-Siegfried #1 and #4 138/69-kV Transmission Line.
The existing Siegfried-East Palmerton #1 and #2 and Hauto-Siegfried #1 and #4 lines have reached the end of their useful lives and the facilities must be replaced in order for the company to continue to provide safe and reliable service, as well as meet its obligations as a public utility, the company said.
PPL Electric said that it also proposes to rebuild the existing Palmerton #1 and #2 138/69-kV Transmission Tap, the Palmerton Zinc #1 and #2 138/69-kV Transmission Tap, the South Slatington #1 and #4 138/69-kV Transmission Tap, and the Ashfield #1 and #4 Transmission Tap.
Phase 2 is the section of the system from the split to the East Palmerton substation, and all associated tap lines, while Phase 3 is the section between the split and the Hauto substation and its associated tap line, the company said.
The project would be built in Washington Township in Lehigh County, as well as Palmerton, Nesquehoning, and Summit Hills boroughs, and Lower Towamensing, Mahoning, and East Penn townships in Carbon County.
The Siegfried-East Palmerton #1 and #2 Transmission Line was built in 1948, while the Hauto-Siegfried #1 and #4 Transmission Line was originally built in 1914 and 1923.
The age of the existing conductor, which dates back to 1948, is an additional asset health concern, the company added, noting that the conductors are past the end of their respective expected life of 65 years. The Siegfried-East Palmerton #1 and #2 138/69-kV Transmission Lines and taps have 250 MCM copper conductors. The company also said that the Hauto-Siegfried #1 and #4 138/69-kV Transmission Lines and taps have a mixture of 96 and 105 4/0 copper and some newer ACSR conductor.
The Siegfried-East Palmerton #1 and #2 Transmission Line conductor is especially concerning since copper conductors of similar vintage on PPL Electric’s system have failed due to a patina developing on the copper over time, which can cause corrosion pits. Those pits can cause micro-cracks, which propagate into larger cracks along the cross section of each strand of wire, eventually resulting in failure, the company added.
Rebuilding the existing single-circuit portion of the lines as double circuits would allow PPL Electric to build the new line on the center of the existing right of way (ROW), in most areas, to increase safety and reliability by increasing the distance between the conductors and the edge of the ROW, the company said.
PPL Electric said that the total estimated cost for the proposed project is about $55.5m.
The company also said that construction on Phase 2 and 3 would begin upon receipt of the commission’s approval of the filing, with an estimated in-service date before the end of 2022.