The Pennsylvania Public Utility Commission, in an April 20 order, approved a letter of notification (LON) filed in March by Duquesne Light, in which the company sought approval to reconfigure two existing 138-kV transmission lines in Allegheny County, Pa.
The PUC said that it does not find the company’s filing “to be inconsistent with the applicable law or commission policy regarding transmission line siting and, therefore, to be in the public interest.”
The company said in the LON that the project is a PJM Interconnection baseline project (project ID B2689) required to relieve congestion on two Duquesne Light 138-kV facilities.
Discussing the need for the project, the company noted that PJM identified congestion on the Dravosburg-West Mifflin (Z-73) 138-kV circuit, and the Woodville-Peters (Z-117) 138-kV tie-line circuit that should be alleviated to help ensure continued economic operations of the bulk power system.
To relieve that congestion, the company said that it proposes to reconductor a portion of the Woodville-Peters (Z-117) 138-kV tie-line, reconfigure the idled Dravosburg-Elrama (Z-15) line segment, reconfigure the present West Mifflin-USS Clairton (Z-14) 138-kV circuits, and create the Dravosburg-USS Clairton (Z-15) and West Mifflin-Wilson (Z-14) 138-kV circuit.
Circuits Z-14 and Z-15 are located in the municipalities of West Mifflin, Jefferson Hills, Dravosburg, and Clairton in Allegheny County, the company said.
The new Z-15 circuit will include energizing six miles of the existing idle transmission line conductors from the Dravosburg substation to structure 3239-1 and connecting to the existing segment of Z-14 from structure 3239-1 to the USX Clairton substation for a total length of 7.9 miles, the company said.
At structure 3239-1, a jumper loop extending from the northwest side of the tower to the northeast side of the tower will be added, the company said, noting that the jumper loop will connect the existing idle segment of Z-15 heading north towards the Dravosburg substation to the existing Z-14 circuit segment on the north side of the line heading east towards the USX Clairton substation.
The jumper loop will energize the Z-15 segment north to Dravosburg from structure 3239-1. The existing jumper loop connecting the two existing segments of Z-14 to the USX Clairton substation and to the Wilson substation will be cut, and the segment from structure 3239-1 north to the Wilson substation will be left idle, the company added.
The new Z-14 circuit will begin at the West Mifflin substation and will utilize 4.77 miles of existing conductor between that substation and structure 3230. New conductor will be installed from structure 3230 and move east, for 0.031 miles, to connect into the Wilson substation, the company added, noting that the new conductor will be installed on company-owned property.
The total length of the new Z-14 circuit will be 4.8 miles. The company also said that the remaining 1.2-mile segment of the existing Z-14 circuit from structure 3230 near the Wilson substation south to structure 3239-1 will become idle.
Construction is scheduled to begin in September, and must be completed by June 1, 2018, the company said.