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Puget Sound Energy electric transmission project

Snoqualmie – Novelty 115 kV transmission line

Summer 2010 project completion
  • Puget Sound Energy completed construction in September 2010

Project overview

PSE upgraded our existing Snoqualmie-Novelty 115 kilovolt transmission line, which runs between Duvall and Snoqualmie Falls, to increase reliability and capacity to meet our customers' current and future needs. We replaced eight miles of transmission lines and three miles of distribution lines along the route with stronger, higher-capacity electric conductors (wires), as well as strung new fiber optic line for PSE communications. We also replaced aging utility poles along the northern eight miles of the route.

Fiber optic lines help PSE monitor and coordinate our electric generation and transmission system remotely through instantaneous communication. Before construction of the new fiber optic lines, PSE managed the existing transmission line through static data points, which required manual manipulation of switches to operate the system – a utility worker had to physically go out to the line to flip the switches. With the fiber-optic line, PSE has the ability to flip the switches from a remote control room. In addition, the new fiber optic line increases the capacity and reliability of PSE's communication network in the Snoqualmie Valley, enabling PSE to better operate the Snoqualmie Falls Hydroelectric Project in coordination with other generation throughout the system.

Download full-sized map

Project map (358 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 generation facilities to substations in local communities. Transmission normally takes place at voltages of 55 kV and higher.

What is a fiber-optic line?

A fiber-optic line or optical fiber is a glass fiber that is designed to direct light along its length and is used for communication purposes. The fiber-optic lines used in our electric system are small, half-inch in diameter lines. Fiber-optic is light, less expensive, and able to carry much more information than radio and microwave communication.

What is a distribution line?

Distribution lines are critical links in the electrical system moving power from electrical substations through distribution transformers directly to homes or businesses. Unlike transmission lines, distribution lines typically carry less than 55 kV; PSE's distribution lines are typically 12.5 kV. Distribution lines can be installed both above and below ground.


Download information

Download these PDF files for more detail on PSE's Snoqualmie – Novelty electric transmission project.
Construction notice, June 2009 (358 KB PDF)
Project map (358 KB PDF)
Vegetation management notice (159 KB PDF)