Hydro One Hearn SS GIS Switchgear Building & Relay Building

Toronto, ON
Owner:Hydro One
Trades:Civil, Electrical, Mechanical, HVAC, Structural
Date:June 2012

Project Description and Scope:

The Hearn SS project was an expansion and update to an existing 115kV Hydro One Switchyard located in the Portlands area of Toronto, ON. The project included the design build of a new 974 square meter (3821 sf) GIS Switchgear Building and a new 656 square meter (7061 sf) Relay Building. The State Group was subcontracted for the civil, electrical, mechanical and structural scope of work. The State Group was responsible for all site works, piling, foundations, grounding, cable trenches, duct banks and underground services installed within an existing live switchyard.

The State Group constructed the elevated GIS Switchgear building which was a 2 story structural frame with precast insulated wall panels. The building has an inside crane operating full length of the building. The State Group also installed all the mechanical and electrical services as well as the interior and exterior finishes. The GIS building was to facilitate routing of high voltage cabling from a raised cable tray system routed from the switchyard via bottom cable entry into the building.

The State Group also constructed the precast clad Relay Building incorporating raised computer flooring, room partitions and furnishings. The scope also included the installation of all required mechanical and electrical services.

The State Group successfully managed the complex installation of over 600 helical piers that needed to avoid all existing underground structures in the existing yard while working around live equipment. The State Group successfully executed this project on schedule.