Siemens uses vacuum interrupters for the first time in high voltage switch gear up to 145 kV

While millions of vacuum interrupter units are used in medium voltage switchgear worldwide, until now they have come up against their limits in the high voltage sector above 72.5 kilovolts (kV). Following intensive research and development in this area, Siemens exhibited high voltage interrupters and gas-insulated switchgear using vacuum technology and so-called clean-air technology up to a voltage of 145 kV for the first time ever at this year’s Cigré in Paris. With this technology, a vacuum interrupter unit performs the switching and arc extinguishing activities. Technically processed and purified air with a mixing ratio of 80 percent nitrogen to 20 percent oxygen – so-called clean air – provides the insulation for the current-carrying conductors inside the housing of the metal-encapsulated, gas-insulated switchgear (GIS). The new outdoor circuit-breaker 3AV1 and new switchgear 8VN1 Blue GIS, with vacuum switching technology and clean-air insulation are scheduled to be launched on the market in 2018. ….