HVDC > HVDC References > North America > CU and Square Butte upgrades
Projects upgrades the existing CU and Square Butte HVDC links, built in 1977-78, in North Dakota and Minnesota.
ABB has completed an upgrade of the control systems for the Square Butte HVDC Scheme and the CU HVDC Project, which link together the states of North Dakota and Minnesota in USA.
New MACH 2TM HVDC control systems has been installed to replace the old analogue control systems, originally installed in the mid 1970’s. Both contracts were awarded in 2002.
Coal Creek substation in North Dakota,
part of CU HVDC system. | CU HVDC System
Great River Energy’s CU HVDC Project, a 1,000 MW HVDC bulk power transmission system between Underwood, North Dakota and Buffalo, Minnesota, was built and commissioned by ABB in 1978. The HVDC system was chosen for |
the CU HVDC Project for its stability over long distances and low environmental impact.
The installation and commissioning of the new control equipment was performed in 11 days for pole 1 and 9 days for pole 2, which is an outstanding world record for a project of this complexity. During these periods the other pole remained in full operation and was not disturbed by the control equipment upgrade and only a short, 1½ day, bipolar outage was needed. The bipole was back in full operation on April 17 2004. This world record commissioning of an HVDC control system was made possible by the thorough factory testing of the MACH 2 equipment and by the dedication of the joint Great River Energy - ABB team.
"This astonishing achievement shows what can be performed when a customer like Great River Energy and a Contractor like ABB cooperate. ABB´s modular based HVDC control system MACH 2 together with the dedication and excellence of a joint workforce made this possible." says Terry Grove, manager Transmission Engineering & Services, Great River Energy .
Center HVDC Station, North Dakota | Square Butte HVDC Scheme
Minnkota Power Cooperative's and Minnesota Power's Square Butte HVDC Scheme was originally built by General Electric and commissioned in 1977. The link goes between Center, North Dakota and Duluth, Minnesota. The link is a |
bulk power transmission system, with a transmission capacity of 500 MW, was built as a reinforcement of the AC system in North Dakota.
The Square Butte control upgrade was coordinated with a total shutdown of the generator unit feeding the HVDC link. Therefore the installation and testing could be performed during a bipolar shutdown. The generator outage started on September 4, 2004 and after an exceptionally smooth installation and testing period all tests were finished and the HVDC bipole was back in full operation on October 18, 2004.
"The success of this project was evident in the excellent performance of the system since commissioning" says Warren Candy, Senior Vice President of Minnesota Power.