As the Hydro-Québec and Ontario Power Generation grids are not synchronized, the Outaouais interconnection substation has a back-to-back configuration to keep them separate while allowing power interchanges between the two.
The Outaouais substation has a capacity of 1,250 MW. It is located on some 93,000 m, north of the 315 kV Chénier-Vignan line. The switching section had to be commissioned in late 2008 and the converter section in mid-2009.
Hydro-Québec awarded ABB the contract for the engineering, manufacture, construction, installation and commissioning of the converter section. ABB then contracted Pomerleau to construct the 3,300 m² control building, the foundations and the steel framework for the electrical equipment in the Converter Section.
The underground concrete foundations extend over a 1.8 km area and there are 6 km of surface conduits to house the electrical cables.
The Outaouais susbstation comprises two 315/230-kV converters, each with a capacity of 625 MW, six 315/75-kV power transformers and a spare, and six 230/75kV power transformers and a spare. Each transformer weighs 256 tonnes.