Why vacuum technology is not a simple scaling from medium to high voltage?

This paper gives some insights about necessary subject areas to bring vacuum interrupter technology from medium voltage to high voltage level. Thereby, design aspects and modifications in the manufacturing process must be considered and are addressed in the paper. As a result, 245 kV 63 kA single break vacuum interrupters will be commercially available in the next years. For extra high voltage levels (> 245 kV), the series connection of vacuum interrupters is better suited for several reasons.