Sinatra 230/138/12.5 kV GIS Substation

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Client: NV Energy
Location: Nevada, USA

POWER designed the new 230/138/12 kV GIS Sinatra Substation to accommodate increasing electrical loads associated with the City Center Project and the MGM casino complex on the strip in Las Vegas. Jointly owned by NV Energy and MGM Resorts International, the new substation provides 500 MVA of transformation capacity at 138 kV and 230 kV. The space-saving design features two lineups of gas-insulated switchgear in a 1.5-acre total footprint. NV Energy required a low profile design with a decorative block wall to blend with surrounding buildings near the busy intersection. POWER’s services included electrical, physical, and civil/structural design, underground HV cable design, coordination study, relay settings, and protective relaying design. The substation features three 138 kV and three 230 kV underground transmission line terminals, with each voltage having two terminals installed initially and the infrastructure installed for a future line. The design also features four 138 kV/13.09 kV, 30/40/50 MVA transformers, and one 230/138 kV, 336 MVA auto-transformer. Major equipment consisted of a six-breaker 138 kV GIS ring bus and four-breaker 230 kV GIS ring bus; two 15 kV, 22-breaker position, metal-clad switchgear units; four 15 kV capacitor banks, with three installed; infrastructure for one future 138 kV capacitor bank; and a new control house. POWER was also responsible for grounding analysis with the nearby 16-inch gas line as well as five jack-and-bore transmission line designs under Interstate 15.