On June 2020 the Transconverter design office successfully completed the testing of new protection unit.

The developed protection unit is meant for smooth charge of input high voltage capacitors and for impact reduction of contact system overvoltage DC on input high voltage modules of converters, particularly such as PSN235 U2 for electric locomotives of 2(3) ES4K series.

The new protection unit withstands the overvoltage with duration of 2 times longer than the previous device. Upon that the developed protection unit has analogous maximum values of a switching voltage (6500 V DC) and a current (250 A).

At the end of 2020 development and operational tests of new protection unit are planned for PSN235 U2 converters for electric locomotives of 2(2) ES4K series.