Transmission System Overview

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 Hydro-Québec TransÉnergie and 272 km by Hydro-Québec Distribution.
d) 91 substations operated by Hydro-Québec TransÉnergie and 11 by Hydro-Québec Distribution.
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-Brunswick 3 785 1,200
Ontario 8 1,920 2,705
New York 2 1,100 1,999
New England 3 2,170 2,342
Total 15* 5,975 8,212**
* 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).
December 31, 2018

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