Vacuum disconnectors an application study

The ageing of vacuum interrupters with combined functions of disconnector and circuit-breaker or switch is studied for compact shielded solid insulated switchgear. Different prototypes are manufactured to investigate the influence of contact materials and contact designs. A test program is presented that realistically represents the ageing as described in the standards. The feasibility to create vacuum disconnecting circuit-breakers, vacuum switch-disconnectors and vacuum earthing switches that respond reliably to the requirements of the standards is demonstrated. Most of the tested designs comply with the current IEC62271-1, −100, −103 and −102 requirements for combined disconnect functions. It is shown that all combined disconnector functions can be realised with suitably designed VIs in a compact and economical way even for environmental friendly, but dielectrically very constraint, shielded solid insulated switchgear.