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Case Study


The Chateauguay back-to-back station is 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 Beauharnais power station, constructed in 1984, and has a maximum power transfer capacity of 1,000 MW at a DC voltage of 140 kV. Châteauguay is one of the largest HVDC back-to-back converter stations in North America, and enables power exchanges between Hydro-Québec and NYPA. 

Back-to-back HVDC installations are most typically used in applications where two asynchronous power systems must be interconnected. Unlike point-to-point HVDC transmissions, in a back-to-back installation both converter stations - the rectifier (converting AC power to DC) and inverter (converting DC power to AC) - are housed in the same location, with DC buses connected through a smoothing reactor. 

Besides controlling the power flow, it can supply reactive power and provide independent dynamic voltage control at its two terminals. 

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.

This is the seventh HVDC upgrade project awarded to Hitachi Energy since 2002.

Main data
Commissioning year: 1984
Configuration: Back-to-back
Power transmitted: 2 x 500 MW
Application: Interconnecting grids;
Upgrade 2009