Vacuum interrupters in high voltage applications

SF₆ circuit breakers are the key technology in high voltage (HV) circuit breakers due to the excellent properties of SF₆ in arc extinction and insulation. Since a few years vacuum is starting to enter in this market for the lower high voltages ratings of 72,5kV and 84kV. The main driver for this evolution is the growing market demand for SF₆ free switchgear mainly for environmental reasons. The use of vacuum interrupters for high voltage applications nevertheless asks for new solutions to achieve the dielectric withstand and capacitive switching performances at voltage levels of 72,5kV and above.