Suppression of Fast Transient Overvoltage during Gas Disconnector Switching in GIS

This paper describes the suppression of the transient overvoltage caused by gas disconnector switching of a small capacitive charging current in a gas insulated switchgear substation. The overvoltage is suppressed by the insertion of a resistor with an appropriate value during the switching. A scale model gas disconnector with the resistor is developed. The overvoltage suppression effect and the charging current breaking capability of the gas disconnector are experimentally confirmed. A prototype ultra high voltage gas disconnector is trial manufactured and tested.