AV Terrace Bay – 120kV SF6 Circuit Breaker Supply and Installation

Project Summary

Our team managed a high-voltage breaker replacement installation, from material procurement and contractor coordination to final commissioning and energization support. The project involved the removal of an existing oil circuit breaker (OCB) and installation of a new SF₆ breaker, including all associated civil, electrical, and control work. The scope of work included:

• Specified and ordered all materials required for the circuit breaker installation.
• Scheduled and coordinated contractors, crane, and equipment.
• Excavated trenches, installed conduits, backfilled, and pulled cables.
• Installed SF₆ Junction Boxes and terminated all AC/DC control cables.
• Installed cable trays, conduits, and wired interconnections for SF₆ breaker control.
• Audited and labeled existing wiring in the Oil Circuit Breaker (OCB) cabinet.
• Removed high-voltage leads and pumped oil from OCB.
• Removed and labeled all field wiring from OCB control cabinet.
• Used crane to remove OCB and relocated it.
• Pumped oil back into relocated OCB.
• Hoisted and secured SF₆ breaker onto concrete pad and installed stairs and platform.
• Installed new copper drop leads and connected grounding to all relevant structures.
• Terminated AC/DC control cables into SF₆ Junction Box A.
• Commissioned breaker installation.
• Supported Hydro One testing documentation.
• Provided energization and startup support after Hydro One MSOs installation.