PPL’s (NYSE:PPL) PPL Electric Utilities on Nov. 27 filed with the Pennsylvania Public Utility Commission a letter of notification to request approval to rebuild the existing single-circuit Breinigsville-Alburtis 500-kV Transmission Line to a double-circuit configuration.
The line extends about six miles from the existing Breinigsville 500-138-69-kV substation in Upper Macungie Township, Lehigh County, Pa., to the existing Alburtis 500-230-kV substation in Lower Macungie Township, Lehigh County, the company said.
The entire project would be built entirely within the existing Breinigsville-Alburtis line rights of way (ROWs) and on PPL Electric’s property for the Breinigsville and Alburtis substations.
The company also said that the project is required to improve reliability and operational performance, reduce the potential for and duration of outages, and increase system operability in Lehigh County.
Subject to the commission’s approval, construction is scheduled to begin in May 2018, to support the in-service date of March 2019.
The company also said that the total estimated cost of the proposed project is about $33m.
The proposed project was presented at the PJM Interconnection Mid-Atlantic Sub-Regional Regional Transmission Expansion Plan (RTEP) stakeholder meeting in April 2015, and has been approved as supplemental project s0864 in the PJM RTEP, the company said.
Further discussing the need for the project, the company noted that the existing Wescosville 500-138-69-kV substation – which is currently supplied by a single 500-kV tap off the existing single-circuit Susquehanna-Wescosville 500-kV Transmission Line – serves customers in parts of Lehigh County.
The Susquehanna-Wescosville line extends from the Susquehanna 500-230-kV substation to the tap point with the Wescosville substation. From the tap point, the company added, the 500-kV line continues to the Breinigsville substation – that segment is referred to as the Wescosville-Breinigsville 500-kV Transmission Line.
The Breinigsville substation is also interconnected with the existing single-circuit Breinigsville-Alburtis line.
The company added that its system planning studies have determined that the loss of the Susquehanna-Lackawanna 500-kV Transmission Line, followed by the loss of the Susquehanna-Wescosville line, an N-1-1 contingency, creates an unacceptable voltage drop and low voltage on the 138-kV and 69-kV transmission lines supplied by the Wescosville substation and the Breinigsville substation.
In addition, the 500-kV yard at the Wescosville substation is directly tapped off the Susquehanna-Wescosville line. That line is about 67 miles long, which puts the line at high risk of exposure to faults, the company added. A fault on the Susquehanna-Wescosville line would trip the 500-138-kV transformer, which is the single 500-kV source for the Wescosville substation. Furthermore, the company added, a fault on the Susquehanna-Wescosville line would remove one of the 500-kV sources to the Breinigsville substation.
To resolve the low voltage and voltage drop concerns on the 138-kV and 69-kV systems caused by the N-1-1 contingency, the company said that it proposes to build a more reliable double bus double breaker 500-kV yard at the Wescosville substation and to rebuild the existing single-circuit Breinigsville-Alburtis line to a double-circuit configuration.
Upon completion of the project, the 500-kV circuit from the Breinigsville substation to the Alburtis substation would be renamed the Breinigsville-Alburtis #1 & #2 500-kV Transmission Line.
The rebuild project would use a combination of conductor and ground wire types due to audible noise constraints and the varying fiber path taken along the circuit, the company added.
To rebuild the existing single-circuit Breinigsville-Alburtis line to a double-circuit configuration, the company said that it would replace 21 existing H-frame structures with 21 new H-frame structures; replace two H-frame structures with new two-pole structures; install two new H-frame structures at the Breinigsville substation; replace three two-pole structures with three new two-pole structures; and replace one monopole at the Alburtis substation with a new two-pole structure.
Among other things, the company said that land use and environmental impacts are anticipated to be minimal due to the fact that the project would be built entirely within the existing ROW for the Breinigsville-Alburtis line and on PPL Electric’s substation properties.