TRC is providing engineering, procurement, construction, and management services for a new 345/115kV gas insulated substation (GIS) under the terms of an Engineer Procure Construct (EPC) contract. This project includes an indoor 115kV gas insulated substation, an indoor 345kV GIS, and four 345/115kV autotransformers. Completion of this project is a critical part of various improvements to the transmission system associated with the North Shore Area Upgrades. The project also includes major improvements at one additional 345kV substation and improvements at three 115kV substations.
Challenges faced on this project include outage sequencing of four existing 115kV circuits and one existing 345kV circuit. With limited outage windows and a range of constraints, the sequencing of the outages is required to be over multiple phases. The multi-phased sequencing results in additional challenges, with energization of sections of the yard (115kV fi rst and then the 345kV). Additional challenges have included an aggressive project schedule and limitations within the work area. Being a GIS, the footprint of the site was restrictive, requiring in-depth construction sequencing in order to meet all activity milestones.
Our response to these challenges included a detailed outage sequencing plan that created the basis for all construction activities and milestones, as well as extensive design efforts. TRC provided detailed engineering services including Civil Design, Substation Design, Protection & Control Design, and Procurement. Our construction management utilized extensive experience within these procedures, as well as adhered to a detailed schedule in order to sequence and complete our deliverables within time and budgetary constraints.