Bipole lines

The tremendous hydroelectric potential of the Nelson River was untapped in the 1960s when the technology became available for the long-distance transmission of high-voltage direct current (HVDC) electricity. Currently, about 80% of our electricity is produced by hydroelectric generating stations on the Nelson River. Manitoba Hydro is world-renowned for research and development in HVDC transmission.

The Nelson River HVDC transmission system includes three lines called Bipole I, Bipole II, and Bipole III. Bipole refers to the positive (+) pole and a negative (−) pole which allows electricity to travel great distances without much loss of power.

Bipole I & II

Before Bipole III’s competition in 2018, over 70% of electricity generated in Manitoba was delivered to customers through Bipole I and Bipole II.

These 2 transmission lines run alongside each other for much of their 895-km route, starting at 2 converter stations (Radisson and Henday) near Gillam, Manitoba. Both lines end in the south at the Dorsey Converter Station.

Because of their proximity to each other, a severe weather event could damage Bipole I and Bipole II at the same time. This would have left us unable to transmit enough electricity to meet demand, resulting in extended outages and potential blackouts.

Bipole III

A helicopter hovers over a partially built Bipole III tower carrying the top part of the tower in a grassy field at sunset.

The top section of a Bipole III tower is carried into place by a helicopter.
Enlarge image.

With the addition of Bipole III in 2018, we added 2,000 MW to our system, strengthening our ability to provide customers with renewable electricity from our Nelson River generating stations.

Bipole III is a 500,000-volt HVDC transmission line linking northern generating stations with southern Manitoba. It includes 2 converter stations: Keewatinohk Converter Station (northeast of Gillam); and Riel Converter Station (east of Winnipeg). An additional 230,000-volt AC transmission line interconnections in the north ties Keewatinohk Converter Station into the existing northern alternating current system.

  • Voltage
    • Bipole I: 900 kV (±450,000 nominal, ±463,000 maximum);
    • Bipole II: 1,000 kV (±500,000 maximum);
    • Bipole III: 500 kV.
  • Length of lines
    • Bipole I: 895 km;
    • Bipole II: 937 km;
    • Bipole III: 1,400 km.