Moscow–Kashira HVDC transmission system
The Moscow–Kashira HVDC transmission system was an early high-voltage direct current (HVDC) connection between the town of Kashira and the city of Moscow in Russia, where the terminal was at 55°39′32″N 37°38′16″E / 55.65889°N 37.63778°E. The system was built using mercury-arc valves and other equipment removed from the Elbe Project in Berlin at the end of World War II. Although primarily experimental in nature, the system was the first true static, electronic, high-voltage DC scheme to enter service. Earlier DC transmission schemes had either used electromechanical converters based on the Thury system, such as the Lyon–Moutiers DC transmission scheme or had been at only medium voltage, such as the 12 kV frequency converter scheme at Mechanicville, New York in the United States.
The scheme had a nominal power rating of 30 MW and was operated at different times as a bipole at ±100 kV or a monopole, with earth return, at 200 kV. For most of the transmission distance of 125 km, the transmission conductor was underground cable but some sections were converted to overhead line. The route of the line was between Kashira and Moscow parallel to the existing 110 kV overhead AC line.
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