Tamarisk Substation

Tamarisk Substation

Location: Green River, Utah

Client: PacifiCorp - Rocky Mountain Power

Completion Date: Design: December 2009; Construction: June 2010

The Tamarisk Substation is a new 138/12.5-kV distribution substation installed to replace the Green River Substation, which had reached the end of it life span. A single 20/30/40-MVA, 138/12.5-kV transformer was installed along with a 12.5-kV, seven-unit, metal-clad switchgear building for the initial development of the project. The site was designed with provisions to upgrade to a 40-MVA transformer and allow for an additional 30/40/50-MVA unit to be installed in the future.

Additional equipment included:

  • Two line disconnect switches with line breaking capabilities
  • Two mobile transformer connection switches
  • A bus sectionalizing switch
  • A transformer disconnect with attached TransRupter protection unit
  • All associated structures, foundations, buswork, conduits and grounding to facilitate the equipment

The switchgear is designed for four feeders and one capacitor bank, one transformer lowside breaker and one bus tie breaker to a future 12.5-kV switchgear. The 138-kV bus was developed to allow for a future bay with a paralleled transformer, distribution switchgear and automatic sectionalizing.

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, relaying protection and equipment control integration, and construction specifications. Design analysis and calculations were performed for the substation structures, foundations, grading, oil containment, bus sag, direct stroke lightning protection, ground grid analysis and site lighting.