Design and tests of vacuum interrupters for high voltage circuit breakers

Today SF6 circuit breakers are the key technology in high and very high voltage circuit breakers due to their excellent properties in arc extinction and insulation. Vacuum entered in this market for the lower high voltages ratings of 72,5/84 kV and is investigated at higher voltages. Today the main driver for this evolution is the growing market demand for SF6 free switchgears mainly for environmental reasons. In this paper, we present our latest investigations in design and test of vacuum interrupters for high voltage applications rated 72,5kV/20 and 31.5 kA. It was designed according to our long standing experience in medium voltage and using simulation tools. This new vacuum interrupter has been tested with success in a new candlestick circuit breaker. Some details about dielectric, short circuit current breaking and capacitive current breaking performances will be given and commented.