Validation of a Non-invasive Measuring Method to Determine the Arc Position of an Axially Blown Switching Arc


  • M. Forschelen
  • P. G. Nikolic
  • M. Stoffels
  • A. Schnettler


non-invasive diagnostics, arc position, arc resistance distribution, optical investigations


Today’s research on circuit breaker concepts for alternative insulation and quenching gases is focused on the understanding of the physical processes during a switching process as well as the interaction of the blow gas flow and the switching arc. In order to determine these influences a non-invasive measuring method is established which allows the determination of the spatial arc resistance distribution of an axially blown switching arc to gain a deeper understanding of the cooling processes. In addition, this system is capable of detecting the position of the switching arc by means of trilateration with a measurement system consisting of multiple capacitive field probes. The measurement system is adapted to a laval nozzle geometry and investigations in nitrogen are performed. The results of these investigations are compared to basic optical investigations on switching arcs within this laval nozzle to validate the applicability of the assumptions made for the position determination.