PPL’s (NYSE:PPL) PPL Electric Utilities on May 17 filed with the Pennsylvania Public Utility Commission (PUC) a letter of notification to request approval to re-terminate the existing Montour-Sunbury 230-kV Transmission Line into an upgraded Milton 230-69-kV substation to resolve reliability and planning violations, as well as to maintain reliable electric service to about 13,000 customers in Northumberland County, Pa.
The proposed project is located in Milton Borough, Northumberland County, the company said, noting that it has provided information about the project to those political subdivisions, which have not objected to the project.
Subject to the PUC’s approval, construction is scheduled to begin in September, to support the scheduled in-service date of December, the company said.
Discussing the need for the project, the company said that the Milton substation – which was originally built in 1973, and serves about 13,000 customers in Northumberland County – currently has only one source of supply, the Montour-Sunbury line. That line extends about 22.9 miles between the Montour substation and the Sunbury substation, but near the halfway point, the Montour-Sunbury line is also connected to the Milton substation via a single 300-foot tap line, the company said.
The Montour-Sunbury line currently terminates and is directly connected to three substations – the Montour, Milton, and Sunbury substations – the company said, adding that that configuration does not comply with its design standards for 230-kV lines, which requires 230-kV lines to be interconnected with only two substations.
Currently, there is no interrupting device for the Montour-Sunbury line at the Milton substation, the company said, adding that if the 230-69-kV transformer at the Milton substation were to experience an outage, electrical service would be interrupted for all 13,000 customers currently served by the Milton substation.
The company also said that the Montour-Sunbury 230-kV and Sunbury-Milton 69-kV lines occupy common double-circuit structures with the Montour-Sunbury line on one side of the tower structure and the Sunbury-Milton line on the other side. A single tower failure at one of those double-circuit structures would cause a voltage violation on the 69-kV bus at the Milton substation, which would result in all 13,000 customers served from the Milton substation to experience low voltage, the company said. That contingency event would cause the Danville-Milton 69-kV Transmission Line to become loaded to 102% of the emergency rating, the company noted.
To resolve the reliability concerns and violations, the company said that it proposes to upgrade the Milton substation to a standard configuration, which would include the installation of an interruption device, and re-terminate the Montour-Sunbury line into the upgraded Milton substation. To connect the Montour-Sunbury line with the upgraded Milton substation, the existing 300-foot, 230-kV single tap line between the 230-kV transmission corridor and the Milton substation would be removed, the company said.
The Montour-Sunbury line would be split near the Milton substation, creating the Montour-Milton 230-kV Transmission Line and the Milton-Sunbury 230-kV Transmission Line, the company said.
The Montour-Milton line would be interconnected with the upgraded Milton substation by construction of a new approximately 300-foot, 230-kV tap line, the company said, adding that about 450 feet of the existing conductor along the first span of the Montour-Milton line would be reconductored.
The Milton-Sunbury line would be interconnected with the upgraded Milton substation by construction of a new approximately 300-foot, 230-kV tap line, the company said, noting that about 450 feet of the existing conductor along the first span of the Milton-Sunbury line would be reconductored.
The company said that in total, it proposes to build about 600 feet of new transmission line and reconductor about 900 feet of transmission line within the existing right of way (ROW) – a total of about 0.3 miles.
To reterminate the Montour-Milton and the Milton-Sunbury lines with the upgraded Milton substation, the company proposes to remove one existing 230-kV steel pole structure, and install two new steel monopole dead-end structures. The company also said that while the existing 230-kV tower structure is a steel lattice tower with an average height of 125 feet, the two new steel monopole dead-end structures would be installed on concrete caisson foundations and would have an average height of about 115 feet.
Among other things, the company said that the total estimated cost of the proposed project is $2.2m.
Separately on May 17, PPL Electric Utilities filed with the PUC a letter of notification requesting approval to replace and re-terminate about 200 feet of the existing single circuit Breinigsville-Alburtis 500-kV Transmission Line in Lower Macungie Township, Lehigh County, Pa.
The proposed project is required to comply with NERC Critical Infrastructure Protection Standard “CIP-014-1 – Physical Security,” which FERC approved in January 2015, and mandates that each transmission owner establish a physical security perimeter around non-exempt transmission substations and the related primary control centers, the company said.
Subject to the PUC’s approval, construction is scheduled to begin in September, to support the in-service date of October, the company said.
Discussing the need for the project, the company said that the existing single-circuit Breinigsville-Alburtis line extends about six miles from the Breinigsville 500-138-69-kV substation located in Upper Macungie Township, Lehigh County, to the existing Alburtis 500-230-kV substation in Lower Macugnie Township.
The company said that it and a FirstEnergy (NYSE:FE) subsidiary jointly share the Alburtis substation, the company said, noting that the PPL Electric-owned Breinigsville-Alburtis line currently terminates into Bay 1 of a PPL Electric-owned switchyard at the Alburtis substation.
The company noted that it is currently sharing a control cubicle in the Alburtis substation with FirstEnergy. There is no secure separation between the FirstEnergy controls and the PPL Electric controls inside the control cubicle, and in order to comply with the requirements of NERC CIP-014-1, the company needs to establish a physical security perimeter around its relay and control equipment.
The company added that in order to comply with the requirements of NERC CIP-014-1, PPL Electric proposes to realign the Breinigsville-Alburtis line from the existing Bay 1 position into a new Bay 2 position at the Alburtis substation. The use of the new bay allows PPL Electric to separate its relay and control equipment at the Alburtis substation from the control cubicle currently shared with FirstEnergy, the company said.
The project would involve the realignment of one span of new 500-kV conductors that would extend about 200 feet from the dead end structure to the new Bay 2 position at the Alburtis substation, the company said, noting that due to a difference in the positions of Bay 1 and Bay 2, the existing conductors would be replaced with new, slightly longer conductors.
No additional poles or tower structures are required for the project, which would be built entirely within PPL Electric-owned property, the company said, adding that no new additional ROW would be required.
Upon completion of the project, the line would be renamed the Breinigsville-Alburtis #2 500-kV Transmission line, the company said.
Among other things, the company said that the total estimated cost of the project is $430,500.