Bay d’Espoir’s Biggest Generating Unit Overhaul

During a busy 2019 capital season, extensive work was completed on unit 7 at the Bay d’Espoir hydroelectric generation facility.

Unit 7 was originally commissioned in 1977, and at 154 MW, it’s the largest of the seven generating units at Bay d’Espoir.  A scheduled unit overhaul in 2019 was part of Hydro’s planned critical preventative maintenance program to ensure that the long-term reliability of the unit, and the power plant as a whole, is maintained.

The overhaul involved disassembling the turbine and generator, inspecting, cleaning, performance testing, refurbishing and doing corrective work on various components. For large, rotating hydraulic generation units such as this, it is essential that the turbine is properly aligned and balanced, able to turn freely, and has adequate clearance from other equipment to prevent rubbing or vibration, and to ensure that it is operating efficiently overall.

Detailed planning and execution were critical to this project given both the scope of the work involved and the importance of the unit to electricity production at the Bay d’Espoir plant. All the completed work was carried out over several months from disassembly, completion of the upgrade work, reassembly, and returning unit 7 to service. It was a dedicated and focused effort on the part of our plant operations, engineering, and work execution teams at Hydro – and one that contributes to the safe, reliable operation of the Bay d’Espoir hydroelectric facility into the future.

Crews undertook several months of work in 2019 for a major refurbishment of unit 7 at the Bay d’Espoir generating plant. The unit was completely dissembled for the project, including removal of the rotor (above).
Cleaning the shaft coupling.