Factors that influence the reliability of relays in high voltage pulse equipment have been analyzed. Low voltage relays

vacuum high voltage relays and electromagnets are used to form the core parts of the equipment

that respectively are "automatic controller" which has strong ability to resist electromagnetic interfer

controller for changing pulse polarity and adjusting the current-limit-resistor. Controlling open and broken of high voltage direct current automatically

converting 200 kV high voltage pulse "+/-" polarity automatically and converting current-limit resistor automatically have been realized.