Sensitivity of Dynamic Resistance of Gas Circuit Breakers to the Arc-induced Contact Erosion

Abstract

Dynamic resistance measurement (DRM) is utilized as a non-invasive method to assess the condition of arc contacts in high voltage gas circuit breakers. The main objective of this study is to determine how sensitive the dynamic resistance of a gas circuit breaker is to the contact erosion caused by arcing in gas circuit breakers. For this purpose, short-circuit current interruption experiments have been performed on a puffer type 24 kV SF6 circuit breaker. The results show that the contact erosion does not occur uniformly on the surface of contacts, therefore until the whole surface is not eroded, the DRM is not able to detect any arc contact length variation. However, the amplitude of average arc contact resistance is in agreement with the amount of erosion.