Nelson River Bipole
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Manitoba_Hydro-BipoleII_Valve.JPG
The Nelson River Bipole is a system of two HVDC lines in Manitoba, operated by Manitoba Hydro. They transfer the electric power generated by several hydroelectric power stations along the Nelson River in Northern Manitoba across the wilderness to the populated areas in the south.
The system includes two rectifier stations: Radisson Converter Station near Gillam and Henday Converter Station near Sundance, one inverter station: Dorsey Converter Station at Rosser (26 km from Winnipeg), and two sets of high-voltage direct current transmission lines, each with two parallel overhead conductors to carry the positive and negative feeds. Both bipole systems have extensive ground return electrodes to allow use in monopolar mode.
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Bipole 1
Bipole 1 runs 895 km from Radisson to Dorsey. It is rated to run at a maximum Potential difference of +/- 450 kilovolts and a maximum power of 1620 megawatts. When it was built between March 1971 and October 1977, mercury arc valves were used to rectify the alternating current. These were the most powerful mercury arc valves ever built. In 1993 the mercury arc valves of one pole were replaced with thyristors, increasing the maximum power and voltage of the line to its current levels. By the end of 2004 the last of the mercury arc valves had been replaced by thyristors.
Nelson_Bipole_Thyristors.JPG
Bipole 2
Bipole 2 runs 937 km from Henday to Dorsey. Bipole 2 can transfer a maximum power of 1800 MW at a potential of +/- 500 kV. Bipole 2 was put into service in two stages. After the first stage in 1978 the maximum transmission rate was 900 MW at 250 kV, which increased to its present figure when it was completed in 1985. Unlike Radisson station, Henday station has always been equipped with thyristors.
History
Construction in 1966 of the 1272 MW Kettle Rapids generating station required a long transmission line to connect it to load centers in the sourthern part of Manitoba. The Government of Canada agreed to finance installation of an HVDC line to be repaid by Manitoba Hydro when the load growth permitted the utility to assume the debt due to the line. The load by the Government of Canada was discharged when Manitoba Hydro bought the line and outstanding debt in 1992. [1]
In 1997 a tornado damaged 19 towers of the DC lines. During repairs, some major customers were advised to curtail load, but imports over the 500 kV lines from adjacent utilities in the United States prevented serious interruption of power.
External link
- Manitoba Hydro (http://www.hydro.mb.ca/our_facilities/ts_nelson.shtml)
- http://www.transmission.bpa.gov/cigresc14/Compendium/NELSON1.htm
- http://www.transmission.bpa.gov/cigresc14/Compendium/NELSON2.htm
- http://www.transmission.bpa.gov/cigresc14/Compendium/Nelson2%20Pictures.pdf
Reference
[1]L. A. Bateman, "A History of Electric Power Development in Manitoba", in IEEE Canadian Review, Winter 2005de:Hochspannungs-Gleichstrom-Übertragung