ColumbiaGrid transmission projects moving forward

ColumbiaGrid members are moving forward with several transmission projects that will strengthen the transmission system in western Washington and Oregon.

At the group’s Aug. 15 board of directors’ meeting, ColumbiaGrid planners gave the board updates on the progress made by various planning teams.

The Puget Sound area study team successfully completed cost allocation on six projects, though the planning for the projects was still undergoing some refinement.

“You never really finish the planning until the equipment’s been ordered and the contracts have been signed,” Jeff Miller, ColumbiaGrid’s vice president and manager of planning, said.

Puget Sound-area projects include reconductoring a 230-kV line between Seattle City Light’s Delridge and Duwamish substations near West Seattle; rebuilding Puget Sound Energy’s Sammamish-Lakeside-Talbot 115-kV lines to 230-kv, then running one line at 115-kV and the other at 230-kV; and reconductoring a 230-kV double-circuit line between Bonneville Power Administration’s (BPA) SnoKing substation and Seattle City Light’s Bothell substation.

Other projects in the study area include adding series inductors between north and south Seattle’s systems, and adding a third 500/230-kV transformer in the Covington area of southeast King County.

The Puget Sound area study team will also expand the northern intertie remedial action scheme (RAS) to include a potential outage combination between Echo Lake, Monroe, and the Columbia River hydro system.

It will also continue to study north-to-south transfer capability in the area, which was identified as an area of concern earlier this year. The West of Cascades North (WOCN) interface, which comprises a group of 500-kV lines in the region west of the Cascades from the Canadian border to south of Seattle, will increasingly face conditions that push the interface beyond its voltage stability limit and should be upgraded, according to a ColumbiaGrid study released in April.

In the northern mid-Columbia area, the study team reported a successful cost-allocation agreement for a new nine-mile, 230-kV line connecting Douglas County PUD’s Rapids switchyard in the East Wenatchee area to BPA’s Columbia switchyard.

Costs will be allocated between the Grant, Chelan, and Douglas County PUDs and BPA. Construction could start in 2014.

The Woodland area study team reported completing a study of a new line that would create an electrical connection through PacifiCorp’s 115-kV system to Clark County. The proposed project would construct a new 115-kV transmission line from the Lewis River substation in Woodland, Wash., past Ariel substation to PacifiCorp’s Merwin substation. Both substations are located on the Lewis River in Cowlitz County.

This alternative is favored over an earlier proposal to construct a 230-kV yard at BPA’s Woodland tap.

The completed study of that proposed project is being sent to the study team and a detailed report is being prepared for presentation at an upcoming board meeting.