Future trends in vacuum technology applications

In the medium voltage range the vacuum switching principle is well established. Today vacuum circuit breakers are available up to 52 kV rated voltage and 80 kA short-circuit current. Based on long term experiences and knowledge from basic research development there is a clear progress into lower and higher voltage ranges and highest interrupting capabilities. In addition to expansion of ratings also new applications for the vacuum technology have been attained. For example loadbreakers and recloser as well as transformer tap changers make more and more use of vacuum tubes. Field experiences reveal high reliability of the vacuum chambers with mean time to failure (MTTF) of several tenthousands of tubeyears. Due to high-tech production processes and modem tube designs vacuum switching devices today are maintenance-free.