USACE Portland


Bonneville Dam, OR



Bonneville First Powerhouse Main Unit Circuit Breaker & Instrument Transformer Replacement; Bonneville Dam, OR

This project improved the reliability and operability for the main unit and transfer bus breakers as well as station service equipment for Bonneville Powerhouse One in Multnomah County, Oregon.

The work included the removal of 480V switchgear, 2.4kV switchgear, 13.8kV switchgear, 13.8kV disconnect switches, surge equipment, 13.8kV bussing, 2.4kV bussing, 2.4kV/480V transformers, 2.4kV/208V/120V transformer, 13.8kV/2.4kV transformers, current transformers, potential transformers, protective relays, CLR’s, 13.8kV Oil Main Unit Breakers (MUB) and disconnects including all associated cable and wiring.

Removal work was followed by furnishing and installation of new 480V switchgear, 13.8kV switchgears, 13.8kV disconnect switches, surge equipment, 13.8kV bussing, 2.4kV bussing, 13.8kV/2.4kV transformer, 13.8kV/480V transformers, 2.4kV/208V/120V transformer, high impedance ground equipment, current transformers, potential transformers, electrical interlocks, protective relays, cables, wiring, meters, CLR’s, 13.8kV vacuum breakers, and disconnects. A new SCADA system was also installed.

The work had to be performed over limited outage periods during 3 consecutive years with multiple construction phases.




Nova Group, Inc. is an equal opportunity employer.