Transmission System Overview
More information on how the transmission system works
Consult our system map Our system
Hydro-Québec TransÉnergie is a leader in transmission system design, operation and maintenance. Recognized the world over for the reliability of its grid, it spares no effort to stay at the forefront of the industry in this regard. Its transmission system is the most extensive in North America, comprising 533 substations and more than 34,272 km of lines at various voltages. The division's fixed assets total $20.9 billion.
| Voltage | Substations (number) | Lines (km) |
| 765 kV and 735 kV | 40 | 11,719a |
| ±450 kV DC | 2 | 1,218 |
| 315 kV | 75 | 5,456 |
| 230 kV | 54 | 3,236b |
| 161 kV | 43 | 2,140 |
| 120 kV | 217 | 6,948 |
| > 69 kV or less | 102d | 3,555c |
| Total | 533 | 34,272 |
| a) Including 289 km of 735-kV lines operated at 315 kV. b) Including 33 km of 230-kV lines operated at 120 kV. c) 3,283 km of lines operated by d) 91 substations operated by |
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| December 31, 2015 | ||
Our interconnections
To offer customers a reliable system and transmission services tailored to their needs, Hydro-Québec TransÉnergie has multiple interconnections with systems in neighboring provinces and states. These facilities allow us to carry out interchanges with New Brunswick, Ontario and the U.S. Northeast.
| Neighboring system | Quantity | Import mode (MW) | Export mode (MW) |
| New York | 2 | 1,100 | 1,999 |
| Ontario | 8 | 1,970 | 2,705 |
| New England | 3 | 2,170 | 2,275 |
| New-Brunswick | 3 | 785 | 1,029 |
| Total | 15* | 6,025 | 7,974** |
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* An interconnection common to New York and Ontario is only counted once in the total. ** 325 MW maximum for simultaneous delivery (export) for the interconnection common to New York and Ontario (not 359 MW). |
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| December 31, 2014 | |||
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