Are vacuum interrupters used in any high voltage applications?

Vacuum interrupters are indeed used commonly in high voltage applications. They function effectively in interrupting electrical currents in power systems, especially in switchgear and circuit breakers designed for high voltage operations. The technology relies on creating a vacuum within the interrupter, which allows for the rapid extinguishing of the electrical arc when the circuit is opened.

The high voltage applications leverage the vacuum's effective dielectric strength, which can withstand electrical stresses better than air or other gases used in traditional interrupting methods. This capability makes vacuum interrupters a reliable choice for modern electrical systems that require both safety and efficiency.

In contrast, the other choices suggest limited or outdated uses of vacuum interrupters, which do not align with their established role in contemporary high voltage infrastructure.