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Puget Sound Energy transmission line project

Woodland - St. Clair transmission line and substation projects


Spring 2015 project updates

  • Construction to improve reliability along the Frederickson – Gravelly Lake line at the Tillicum Tap will begin as early as summer 2015.
    • This will include relocating and upgrading an automatic switch to improve electric reliability in the area.
  • Construction of the transmission line between the old Fern Hill substation site in Tacoma and the Woodland substation in Puyallup is expected to begin as soon as 2018-2020.
  • Construction of the Gravelly Lake substation to South Tacoma Way transmission line upgrade was completed in 2012.

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Project overview

To increase reliability for up to 28,000 customers and meet the growing demand for power in Pierce and Thurston County, Puget Sound Energy is upgrading the existing low-voltage de-energized 55 kilovolt (kV) transmission lines to 115 kV standards. These projects will include upgrading one substation and rebuilding or upgrading about12 miles of transmission line.

The multi-year construction effort includes the following projects and expected timelines: 

2015 - 2020 projects
  • Automatic switch: PSE will relocate and upgrade an existing automatic switch along the Frederickson – Gravelly Lake line to increase reliability for up to 2,600 customers. Construction is expected to begin as early as summer 2015.
  • Rebuild transmission line: PSE will rebuild 7.5 miles of existing de-energized 55 kV transmission line to115 kV standards from our old Fern Hill substation site in Tacoma to the Woodland substation in Puyallup.
  • Woodland substation in Puyallup: PSE will rebuild the existing Woodland distribution substation to add transmission circuit breakers which will provide 115 kV switching and transformation capabilities. Construction could begin as soon as 2018.
Completed project
  • Tree trimming and removal: To prepare for replacement of the existing transmission line with the current standard 115 kV line, PSE trimmed and removed trees along approximately five miles of existing transmission line between our Woodland substation in Puyallup and our Fern Hill substation in Tacoma.
  • Transmission line upgrade: PSE rebuilt and relocated 4.5 miles of 55 kV transmission line to our now current 115 kV standard from South Tacoma Way to the Gravelly Lake substation in Lakewood.

What is a transmission line?

Transmission lines are key elements in the electrical distribution system. The lines safely transport high voltage electricity from power generation sources like dams and wind generating facilities to substations in local communities. Transmission normally takes place at voltages of 55 kV and higher.

What is a substation?

Substations are critical links in the electricity distribution system, containing utility circuit protection, voltage regulation, and equipment that steps down higher voltage to lower voltage. Before reaching homes and businesses, power is routed through our transmission system to a substation where it is changed to a lower voltage that can be utilized by customers.