Bochum 2015 – scientific programme

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P: Fachverband Plasmaphysik

P 23: Plasma Technology II

P 23.1: Invited Talk

Wednesday, March 4, 2015, 16:30–17:00, HZO 30

Physical Modeling and Numerical Simulation of Vacuum Switch Arcs — •Norbert Wenzel — Siemens AG, Corporate Technology, Günther-Scharowsky-Str. 1, 91058 Erlangen, Germany

Vacuum arcs are successfully used in vacuum interrupters for medium-voltage (1kV - 36kV) and high-voltage (above 52kV) applications. Switch arcs in vacuum are metal vapor plasmas drawn between separating contact electrodes and sustained by contact material during current interruption. The contact systems are generally designed to superimpose a magnetic field to the arc plasma in order to stabilize the arc in a diffuse mode or to force the arc to move in a constricted mode across the contact surfaces. The extension of such arc control techniques to high currents and voltages constitutes a technological challenge requiring advanced concepts of electrode designs. Physical modeling and numerical simulation of vacuum arc plasmas are suitable approaches to develop such concepts, particularly if plasma modeling is closely coordinated with appropriate modeling of cathode and anode phenomena. This presentation is dedicated to theoretical description of physical processes in diffuse and in constricted vacuum arcs that burn in axial and in radial magnetic fields, respectively. Particular emphasis is placed on fundamentals and application status of a magneto-hydrodynamic plasma model. Results of simulations are reported using commercial simulation software. The computations are compared with experiments under realistic switching conditions. The investigations are performed in context of general trends of switching applications. Possible directions of future research are discussed.