The Escalante 345kV Substation was designed and constructed to interconnect a 34.5 kV collector system from the SunEdison owned Escalante 1, 2, and 3 solar projects in Beaver County, Utah, and provides a path to market for the new solar projects. Each solar project consists of 80 MW of solar generation that is combined at a single substation (240 MW total). As part of an EPC team, M&S Engineering design teams provided all engineering design associated with the generation tie line, overhead collector systems and substation.
The 1/2-mile 345kV generation tie transmission line was constructed to interconnect the solar project to the existing transmission line and to accommodate both the Escalante substation and the adjacent, Rocky Mountain Power owned, Hickory substations and was designed using guyed, direct imbedded, monopole dead-ends and tangent structures with braced-post insulators. Due to an endangered avian species in the area, special “raptor” protection devices were affixed to the insulators. M&S Engineering provided detailed PLS-CADD design, construction management and cost estimating services for this portion of the project.
The overhead collector system was designed using 69kV standards to allow for higher fault duty and avian protection. The two (2) lines were designed using PLS-CADD and are collectively four miles long, with their purpose being to connect Escalante 1 and Escalante 3 solar projects to the collection substation while by-passing Escalante 2. The lines were constructed 795 ACSR conductor, double circuit with OPGW, using braced post insulators and wooden poles, with ruling span of 300 feet.
M&S Engineering provided detailed design for all civil, structural, electrical and foundations, and also provided system protection coordination review with relay settings. Power flow, short circuit analysis, protection coordination, arc-flash, harmonic analysis and complex studies, such as transient overvoltage (TOV), capacitor switching and Ferro-resonance studies were performed by Electric Power Engineers via subcontract. SCADA design, integration and commissioning was performed via subcontract by Sebasta Engineering.