Kashira High Voltage DC Line - Moscow

The Moscow-Kashira high-voltage direct current line was one of the first high-voltage direct current lines in the USSR , launched in 1950 ^[1] . The line connected Kashira and Moscow , the substations of the line were at The system was built using mercury converters and other equipment used in the Elba project in Berlin at the end of World War II ^[2] .

Being essentially an experiment, the system was the first fully static high-voltage electronic direct current circuit put into operation. Early DC power circuits either used electromechanical converters based on Türi systems, such as the Lyon – Moutiers DC transmission scheme, or were just medium voltage, such as a 12 kV frequency conversion circuit in in the United States .

The circuit had a rated power of 30 MW and at different times operated as bipolar at ± 100 kV or as monopolar, with return to ground, at 200 kV. For most of the 112 km route, the line was presented as a high-voltage cable , but some sections were converted into an overhead line . The line route between Kashira and Moscow runs parallel to the 110 kV AC overhead line.

The first operational experience was obtained using three mercury rectifiers with one anode connected in series in each arm of the converter, but in 1959 it was possible to work with two mercury rectifiers in series, or even one mercury rectifier in each arm.

The operation of several rectifiers connected in series was not particularly successful, and judging by the available records, the circuit had very dubious reliability. This is because the mercury rectifiers, unlike those developed in Switzerland by Dr. Uno Lamm , lacked an external anode voltage divider, which was necessary for reliable operation in high voltage circuits.

Nevertheless, the valuable experience gained was applied to the construction of a much more powerful ± 400 kV line Volgograd-Donbass , the project of which was completed in 1965 with the use of mercury rectifiers completely Soviet-made.

In 1969, the first thyristor switch created in the USSR was installed in the converter ^[3] . Now this system has not been used for a long time and there is no data left about when it was decommissioned. It is also unknown whether the cable and converter complex in Kashira has survived. .