McPhee Electric provided services to engineer, procure, and construct a new green field 115kV substation incorporating Bulk Power System standards as part of the NEEWS-Greater Springfield Reliability Project. McPhee provided the following electrical construction scope of work at Cadwell:
- Excavation and backfill for conduits, grounding, and foundations
- Construction of drilled shaft and pad/pier foundations for equipment and steel structures
- Erection of A-frame structures and other steel supports
- Installation of underground grid and above-grade grounding
- Installation of 115kV SF6 circuit breakers, motorized and manual disconnect switches, CCVT’s, surge arresters, and air-core reactors
- Installation of rigid and strain bus work
- Installation of site lighting
- Installation of control enclosure
- Installation of protection and control cabinets, and both copper and fiber-optic cabling
- Implementation of IEC 61850 communication protocol for the protection and control system
- Installation of AC and DC distribution systems for the control house and equipment
The Cadwell 115kV Switching Station is part of the Greater Springfield Reliability Project, one of the four main transmission projects comprising the New England East-West Solution (NEEWS) Projects.
The work at Cadwell Switching Station consisted of the design and construction of a new breaker-and-one-half 115kV, five-line position, three-bay switching station. This ring bus is ultimately convertible to a four-bay breaker-and-one-half configuration.
Challenges included constructing the substation in an existing transmission right-of-way, including sequentially shifting overhead lines onto new structures to temporary interim positions, to allow for construction of the substation, while maintaining existing transmission circuits.