Snohomish County Public Utility District No. 1

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Customer Service (M-F 8a-5:30p): 425-783-1000

Northeast County

Aerial photo of East Arlington Substation and Eagle Creek Substation site

Timeline: 2017-2019

The Background

The East Arlington and Oso communities are some of the most challenging areas for reliability in the PUD’s electrical system. While the utility cannot guarantee uninterruptible power at all times due to forces of nature, it can upgrade its infrastructure to help minimize power outages and their duration. The substations in Arlington and Oso have aging infrastructure and are greatly in need of equipment upgrades.

“This project required considerable planning to ensure that power won’t be interrupted during the two year construction timeline,” said PUD Project Manager Bob Anderson. “Our project team has done an exceptional job of designing the work to coordinate the multiple stages of the Oso/East Arlington improvements.”

The Project Summary

The PUD has made a series of electrical system improvements in the Arlington and Oso communities, consistent with its overall grid modernization efforts. They will provide additional options for the PUD to serve these communities, which aids reliability during major storms and as the utility performs system maintenance. The key project components include:

  • Construction of a new Eagle Creek substation, south across the street from the existing East Arlington substation, to allow for upgrades to the East Arlington substation.
  • Rebuild of the East Arlington substation with a high reliability six breaker ring bus.
  • Upgrade of the last of the legacy 55kV lines to 115kV lines between the Oso and East Arlington substations, including fiber optic cable.
  • Upgrade of the Oso substation with PUD standard 115kV equipment.
  • Distribution Automation upgrades as part of the PUD's smart grid modernization.


  • These improvements provide more options to serve these communities, allowing the PUD to re-route customers to different substations when needed during outages and maintenance to minimize the number of impacted customers.
  • Modernization of substations and high-voltage lines will bring equipment up to date with other parts of the PUD’s electrical system.
  • A subsequent Distribution Automation project will be implemented in the next two years as part of the smart grid modernization throughout the PUD’s system.