Project Description

The Bipole III transmission project involves the construction of:

• a 500-kilovolt HVDC transmission line linking the northern power generating complex on the Lower Nelson River with the conversion and delivery system in southern Manitoba;
• 2 new converter stations – one in northern Manitoba northeast of Gillam (Keewatinoow) and one east of Winnipeg at the Riel Station site;
• 2 ground electrodes – one at each converter station;
• additional 230 kV transmission line interconnections in the north to tie the new converter station into the existing northern AC system.

The Bipole III ± 500 kV HVDC transmission line will:

1. originate at a Keewatinoow converter station site near the proposed Conawapa Generating Station site;
2. travel west and south towards The Pas;
3. travel south, staying west of Lake Winnipegosis and Lake Manitoba;
4. pass south of Portage la Prairie and Winnipeg to terminate at the Riel Converter Station site, in the RM of Springfield.

The preliminary preferred route is approximately 1,364 km in length.

Bipole III transmission line will be strung on steel tower structures on a 66 m wide right-of-way, with an average tower spacing of approximately 480 m resulting in 3 to 4 towers per mile. In agricultural areas, self-supporting towers will be used to reduce effects on agricultural operations. Guyed towers will be used in forested areas and other areas that are compatible with the use of this tower type.

View a self-supporting suspension tower.

View a guyed suspension tower.

Two new converter stations are also required for this project. Hydro-electricity is generated at the northern generating stations as AC power, then converted to DC for transmission, and inverted at the southern terminus to AC power for end use. DC power transmission is more efficient than AC over long distances. The converter stations are large complexes consisting of AC and DC switchyards, switch gear, converter transformers, valve groups, filters, and ancillary systems for cooling and operation. A converter building will house 250 kV valve groups along with control equipment at each site.

New 230 kV AC transmission lines will be required to connect the new Keewatinoow converter station near the proposed Conawapa site to the existing Henday Converter Station and Long Spruce Generating Station in northern Manitoba.
View northern Manitoba route map.

Ground electrode facilities will also be required for the operation of the 2 new converter stations, to be located near the Riel site in the south and the Keewatinoow site in the north. Ground electrodes are required to provide a connection to ground at each converter station, and will be constructed on sites that are well separated from the converter stations. A low voltage feeder line is required to connect the ground electrode to the converter station.