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Eliot Substation

Eliot Substation, Eliot, ME

New 345kV Switchyard

Eliot Substation is a new greenfield station, located in Eliot, ME. This station is comprised of a 345kV switchyard, with a (3) line double breaker ring bus configuration, and new control house. The design for the new substation connected the existing 345kV Newington-Deerfield 307 line, located in New Hampshire, to the Central Maine Power (CMP) System.  At project completion, there were (3) new 345kV line terminals constructed at Eliot Substation; #307 from Deerfield, #3176 from Newington, and #3022 to Maguire Road.

Engineering, Design, and Procurement and Construction Support Services Included:

  • (2) 345kV bays with (4) breakers in (1) bay and (2) breakers in the second bay (initially), in a ring bus configuration.
  • An ultimate configuration of (8) 345kV double breaker bays for (4) line terminals.
  • Control house – Pre-engineered steel building.
  • The 345kV switching yard classified as a Bulk Power System (BPS) facility.

Realtime’s responsibilities included the design and engineering of the substation line terminals; bus and yard equipment (GA) layout; specifications of all equipment; design of the steel support structures and foundations; development of the grading and elevations in the yard; fence detail, interior road paving, yard surfacing; design of yard lighting, ground grid system, and lightning protection system; preparation of performance specifications for the prefabricated control house, including the HVAC, lighting, and cable tray systems; and design and detail of the underground trench system. Realtime sized and designed the 125 VDC batteries and charger systems, emergency generator for current and future loads, DC panel boards, 120/240 VAC panel boards, station service transformer with fused safety switch, and auto-transfer switch.  Engineering provided studies and analysis, as required, for the battery sizing, bus bar rating, lightning protection, ground grid design, station service AC and DC loads, and civil/structural analysis.

Realtime engineered and designed the 345kV protection and control systems for all lines, buses, and breakers. The communication systems utilize IEC 61850 technology with a synchroscope, wired to breaker failure auxiliary relays, for line voltage selections.  Realtime coordinated the IEC 61850 communication network design with Siemens Corporation, through our Client, and developed logic diagrams.  Design of connections to the IEC 61850 network, alarm annunciation, SCADA, and fiber optic loop were also provided by Realtime.

Engineering provided complete procurement and construction support services, including review of all shop drawings and trade prints. Realtime assisted with bid packages, bid evaluations and procurement activities, vendor RFIs, field construction issues and RFIs; and preparation of as-built drawings and documentation for project closeout.