Berlin 2014 – scientific programme

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P: Fachverband Plasmaphysik

P 3: Plasma Technology I

P 3.4: Talk

Monday, March 17, 2014, 15:15–15:30, SPA HS201

Speckle and Shadowgraphy Techniques for the Diagnostic of Switching Arcs — •Jan Carstensen, Emmanouil Panousis, Patrick Stoller, and Michael Schwinne — ABB Corporate Research, Baden-Dättwil, 5405, Switzerland

Gas circuit breakers (GCBs) are vital for the protection of electricity transmission networks. The interruption of high currents at high system voltages is done by the quenching of electric arcs. The diagnostics of these kind of arc discharges is challenging because of the short time and length scales involved but indispensable for a better understanding of the switching capability of GCBs. In this contribution shadowgraphy and speckle measurements of the high and low current phase of switching arcs are presented; they are sensitive to the first and second derivatives of the refractive index of the arcing medium, respectivley. The combination of a 20 ns pulse laser with a high resolution camera (16 MP) reveals the boundary layer between the arc and the superimposed gas flow in detail. For nearly axis-symmetric arcs, it is even possible to obtain quantitative information about the gas density and temperature in the arcing zone.