Switching of capacitive currents

The new IEC 62271-100 requires an extensive proof of the capability of capacitive switching for a breaker under test. For vacuum circuit breakers. dielectric properties are mainly determined by the condition of the contact surfaces, which are modified by in-rush currents as well as load-breaking currents. A synthetic single-phase test device has been erected in order to investigate these dependencies in detail and to get knowledge of the statistical properties of the investigated interrupters. The results are evaluated with respect to pre-ignition field strengths and contact strokes. Application to commercial solutions are presented coping with the required standard class C2.