To accomplish a capacity expansion for the city of Medford, Ore., the existing 69-kV Line 3 was upgraded to 115-kV, nearly doubling its power handling capability. Substation upgrades occurred at eight sites. Baldy Switching Station was a new three-position ring bus configuration that replaced an existing station (containing only switches) with new line relaying toward Lone Pine, Sage Road and Copco substations.
Similarly, new protection and control panels were installed at these sites to upgrade the line relaying and the corresponding breaker controls. Belknap Substation was upgraded to allow for a new line position and relocation of a 115/69-kV transformer from Ashland Substation. New transformer protection and line protection relaying towards Ashland was also installed. Talent Substation, located between Belknap and Ashland, was initially designed for this 115-kV upgrade and required new CCVTs and new ratios for the existing CTs along with a high-side voltage change of the transformer. Work at Ashland Substation included the removal of the 115/69-kV transformer bay as well as installation of a new 115-kV breaker and corresponding line protection to Oak Knoll Substation. Oak Knoll Substation was upgraded to include a new 115-kV breaker and line relaying towards Ashland and Copco. Additionally, Oak Knoll Substation was expanded to allow for a new control house, mobile access, and all new protection and control relaying for the entire site.
Burns & McDonnell was responsible for the design and coordination of the electrical, physical and civil design including one-line diagrams, three-line diagrams, AC and DC schematics, general arrangement plans and elevations, conduit plans and details, grounding plans and details, foundation plans and details, material procurement, and construction specifications. Design analysis and calculations were performed for the substation structures, foundations, grading, oil containment, retaining walls, fencing, buswork, ground grid, lightning protection, and site lighting at the various sites.