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Panorama of Montreal, Quebec, Canada, and the Saint-Lawrence river in fall 2018.
Customer Success Story


Châteauguay is one of the largest back-to-back HVDC converter stations in North America and enables power exchanges between Hydro-Québec and NYPA

Commissioned four decades ago, Châteauguay is located southwest of Montreal, Quebec, Canada and consists of two independent 500 MW modules. Owned by Hydro-Québec, it is supplied from a 315 kV source on the Hydro-Québec side, and a 120 kV source on the New York Power Authority (NYPA) side. Generation is supplied by the Beauharnois power station, constructed in 1984, and has a maximum power transfer capacity of 1,000 MW at a DC voltage of 140 kV. In 2008, Hitachi Energy received a contract to upgrade the station. The control and protection system was replaced by a fully digital MACH system in 2009. Since the station comprises two blocks and each block was renovated separately, the station maintained at least half its capacity during the installation period. 

Substantial modernization of a key transmission system in Canada will boost the transfer of electricity between Montreal and New York

In 2022, Hitachi Energy has been selected to supply its high-voltage direct current (HVDC) power system technology for the transmission of electricity between the Québec grid, in eastern Canada, and New York in the northeastern United States. 

The Châteauguay HVDC system will enable the transmission of up to 1,500 megawatts of electricity between the electrical networks of Quebec and the state of New York, which will contribute to maintaining a low carbon footprint in the region. This new system will replace existing equipment which has been in operation since 1984, increasing the efficiency and controllability, plus raising the power conversion capacity of the Châteauguay HVDC system by 50 percent. 

Hitachi Energy is supplying a “back-to-back” converter station, which converts AC power to DC and then reconverts it to AC from DC enabling the interconnection of the 735-kilovolt Canadian and 765-kilovolt New York grids which are “out of phase” and cannot be connected directly via traditional AC systems.

Main data 
Commissioning year: 1984 (commissioning year)
2009 (upgrade)
2022 (upgrade)
Configuration:  Back-to-back 
Power transmitted: 2 x 500 MW
1,500 MW (upgrade)


Extensions, Upgrades, and Retrofits
Interconnecting Grids