Fault interruptionWhen breaker contacts separate under fault current, an electrical arc forms between them. It is not a requirement to immediately remove all existing SF₆ equipment from service. A typical European 33 kV BESS collection system falls into the second category. The transition away from SF₆ does not mean abandoning GIS or returning every project to large outdoor AIS substations. Vacuum interruption with dry-air insulationThis is becoming one of the most important solutions for medium-voltage switchgear.