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Puget Sound Energy substation and transmission line project


Boeing Aerospace substation and 115 kV transmission line

Summer 2013 project completion
  • Construction of the substation began in September 2010 and was completed in May 2011
  • We began construction on the transmission line in May 2013 and energized the line on July 30, 2013
Project overview

Puget Sound Energy expanded the Boeing Aerospace substation at 20403 68th Ave. S in the Boeing Space Center property in Kent in order to increase reliability and meet growing demand for power in south King County. The expanded substation includes an additional 25 megavolt ampere transformer and four new circuit breakers.

In addition, PSE constructed 1.5 miles of new 115 kilovolt transmission line from the Boeing Aerospace substation to the existing 115 kV line, located near Frager Road, north of South 196th Street, in order to increase the reliability of the electric system and allow for better use of existing capacity in the Kent area. Previously, the Boeing Aerospace substation was served radially, meaning it was served by one transmission line. If the line serving the substation went out, the substation and the customers served by it lost power. The new transmission line creates a "loop," which means the substation is fed by two transmission lines. If one line goes out, the other line will still feed power to the substation and customers.

Download full-sized map

Project map (697 KB PDF)

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.


Download information

Download these PDF files for more detail on PSE's Boeing Aerospace substation and transmission project.
Project map (697 KB PDF)