Hydro-Québec Commissions 735 kV Substation Transformer Upgrade at Chamouchouane
Hydro-Québec has commissioned 3 autotransformer banks rated at 1100 MVA each at the 735 kV Chamouchouane substation, strengthening bulk power transmission from northern hydropower complexes to southern urban load centers.
- Publish date: 2026-10-04
- Category: HVDC & Substations
- Original source: Hydro-Québec TransÉnergie Media
- Reading time: 1 min
Extra-High Voltage Transmission Reinforcement
The newly upgraded 735 kV switchyard integrates 9 single-phase units rated at 370 MVA each into 3 three-phase 1100 MVA three-phase autotransformer banks connecting to 210 km of extra-high voltage lines.
Designed for severe subarctic winter conditions, the equipment incorporates arctic-grade dielectric fluids that maintain operational performance at temperatures down to -45 °C.
Clean Hydropower Delivery and Grid Reliability
The expansion increases transmission transfer capacity by 1500 MW, enabling surplus hydro energy from James Bay generating stations to flow reliably toward Greater Montreal.
Advanced optical current transformers and redundant numerical relays ensure fault clearance times under 40 ms, minimizing voltage disturbances across the provincial grid.