Square Butte is the designation of a
high-voltage direct current
A high-voltage direct current (HVDC) electric power transmission system (also called a power superhighway or an electrical superhighway) uses direct current (DC) for electric power transmission, in contrast with the more common alternating curre ...
transmission line in the United States between the
Milton R. Young Power Plant near
Center, North Dakota
Center is a city in Oliver County, North Dakota, United States. It is the county seat of, and the only incorporated place in, Oliver County. The population was 588 at the 2020 census.
History
Center was founded in 1902. The city was named from ...
at and the Arrowhead converter station near Adolph (a neighborhood of the city of
Hermantown near the city of
Duluth, Minnesota
, settlement_type = City
, nicknames = Twin Ports (with Superior), Zenith City
, motto =
, image_skyline =
, image_caption = Clockwise from top: urban Duluth skyline; Minnesota ...
) at . It was built by
Minnkota Power Cooperative and
Minnesota Power and went in service in 1977. In 2009, an agreement was executed between the two companies whereby Minnkota gets the rights to all the power currently transmitted over the line (and which is now carried over a newly built 345kV transmission line) while Minnesota Power takes full ownership of the line to transmit power from new sources in the Center area.
Square Butte can transfer up to 500
megawatts
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Watt ...
at a symmetrical voltage of 250 kV. The whole line is implemented as overhead line on steel lattice towers, with a single conductor per
HVDC pole (i.e. a total of two for the HDVC bipole), with a length of 449 miles (749 kilometers). The line crosses the
Missouri River north of Price between and in a 718 metres long span. As is the case for modern HVDC-systems
thyristor
A thyristor () is a solid-state semiconductor device with four layers of alternating P- and N-type materials used for high-power applications. It acts exclusively as a bistable switch (or a latch), conducting when the gate receives a current ...
static inverters are used.
Crossing another HVDC line
Southeast of
Wing, North Dakota
Wing is a rural town, small town in Burleigh County, North Dakota, Burleigh County, North Dakota, United States. It is part of the "Bismarck, North Dakota, Bismarck, North Dakota, ND Metropolitan Statistical Area" or "Bismarck-Mandan". The popula ...
, at Square Butte crosses
CU, another HVDC powerline. This is the only crossing point of two HVDC overhead powerlines in the Western hemisphere.
Electrode line
The ground return
electrode line
An electrode line is used in some high-voltage direct-current (HVDC) power transmission systems, to connect the converter stations to distant ground electrodes. Many long-distance HVDC systems use sea or ground return for the DC neutral current ...
starting at Adolph Static Inverter Plant is installed on portal pylons of the three phase AC-powerline from Adolph Static Inverter Plant to Marble Substation. It ends at {{Coord, 46, 55, 29, N, 92, 41, 50, W, type:landmark, name=End of electrode line of Square Butte.
The electrode line starting at Adolph Static Inverter Plant consists of two underground 15 kV cables, each using aluminum conductors with a cross section of 380 mm
2.
External links
* ABB (2005)
Upgrade of control system for CU and Square Butte HVDC projects Retrieved March 27, 2005.
THE SQUARE BUTTE HVDC SCHEME – Geographic map
Energy infrastructure completed in 1977
Electric power transmission systems in the United States
Energy infrastructure in North Dakota
Energy infrastructure in Minnesota
Duluth, Minnesota
1977 establishments in Minnesota
1977 establishments in North Dakota
Buildings and structures in Oliver County, North Dakota