By Mike Hill, Engineering Manager
Liberty Station
Liberty Station will be a 115 kV transmission line Switching Station located on PUD-owned property directly north of Bonneville Power Administration’s (BPA) Port Angeles Substation near Peninsula College.
The project was designed by Electrical Engineer Ben Phillips. Contracted work includes site preparation, and concrete foundations followed by installation of a control house, steel support structures, electrical equipment, ground grid, and conduit. The PUD Substation crew will install the relay panels, control wiring, and 115 kV buswork while the PUD Facility assistant crew will install the fence. Construction of Liberty Station will begin in June 2024 and is scheduled to be completed in October 2024. The total cost of materials and contract labor is approximately $1.2 million, not including BPA costs.
Several transmission/distribution rebuild and substation projects from 2008 to 2023 have been completed in anticipation of this project. These projects consisted of replacing wood transmission poles with fiberglass, upsizing conductors, changing the transmission insulators from 69 kV to 115 kV, decommissioning the 69kV Joyce Substation, building the new 115 kV Silverado Substation, and 69kV to 115kV conversion of Laird and Airport Substations.
PUD’s Silverado Substation is currently fed “radially” from BPA just west of Joyce and PUD’s Laird and Airport Substations are fed radially from BPA in Port Angeles. Radially fed lines and substations are only fed from one source of power, which works fine until repairs or maintenance on the energized power lines are required. For example, if a car/pole accident were to happen that affected the transmission line between BPA Port Angeles and Airport Substation, all customers fed off Laird and Airport Substations would be out of power until repairs were made.
Liberty Station was designed to facilitate a “loop” feed to Airport, Laird, and Silverado Substations. Loop-fed lines and substations can be fed from more than one source of power. For example, in the scenario above, rather than Airport and Laird substation customers having to wait until the car/pole repairs are made before their power is restored, PUD can feed them through BPA in Joyce. Loop feeds are also very beneficial for maintenance projects such as transmission pole replacements. The loop feed allows the transmission work to be done on de-energized power lines. Currently, PUD either works on energized lines or schedules an outage to perform maintenance tasks.
Dungeness Substation Line-C to Sunland Substation Line-C 750 MCM Tie
This project consists of building a new section of the distribution power line to connect Dungeness Substation Line-C to Sunland Substation Line C, creating a loop feed with a potential route along Anderson Road, Clark Road, and Lotzgesell Road. The new section of line will consist of 556 AAC overhead powerlines and 750 MCM 3-phase underground cable, 250’ of which will utilize previously installed conduit. Construction is expected to begin in spring and be complete this fall with PUD crews performing all of the work. The key benefits of this project include increasing reliability for 4,229 customers due to the loop feed and providing additional means to offload the corresponding substations when needed. We do not have a map available as of the printing of this newsletter because the exact route was still being designed.