King County

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Puget Sound Energy substation project

Four Corners substation

Fall 2009 project updates

PSE began construction in April 2009

Construction is expected to be complete in November 2009

Project Overview

PSE is building a new electric distribution substation to meet increased demand for electricity in the Maple Valley area. Our new Four Corners substation will be located at 27430 Maple Valley Black Diamond Road SE (State Route 169). Our substation will increase electric capacity and reliability to customers in the Maple Valley area. When complete our substation will include one 25 megawatt (MW) transformer and have the space to add a second 25 MW transformer, which will allow PSE to double the capacity in the future without changing the substation footprint.

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Project Map
(367 KB PDF)

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.

Committed to keeping you informed

PSE will continue to provide updates to the community. We will notify residents near the project area when construction will occur. We aim to complete the work with as little disruption as possible.