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Dynamics of arc phenomena at closure of electrical contacts in vacuum circuit breakers

Kharin, Stanislav N.; Nouri, Hassan; Amft, D.


Stanislav N. Kharin

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Hassan Nouri
Reader in Electrical Power and Energy

D. Amft


Dynamic phenomena accompanying electrical contact closure in vacuum circuit breakers are considered as consecutive stages, including breakdown, touch, compression, restitution, bridging, and arcing at bouncing. The hybrid mathematical model is elaborated to describe dynamics of the arc and forces acting in the contact gap. The model uses experimental oscillograms of current, voltage and contact displacement and nonlinear equations for arc, anode and cathode temperature fields, and contact motion. Experiments are carried out using a standard vacuum circuit breaker with laser sensors for the measurement of contact gap. The special difference path method is applied to take into account oscillations of a fixed contact. The axisymmetric Stefan problem with two free boundaries corresponding to melting and evaporation interfaces is solved to find dynamics of contact evaporation. It is shown theoretically and confirmed experimentally that in the range of high currents, the force of metallic vapor pressure at arcing in vacuum is comparable with magnetic repulsion force and should be taken into consideration. Two mechanisms of vapor pressure formation and evolution are discussed, which occur due to explosion of micro-asperities at contact touch or due to arcing after bridge rupture at contact bouncing. © 2005 IEEE.


Kharin, S. N., Nouri, H., & Amft, D. (2005). Dynamics of arc phenomena at closure of electrical contacts in vacuum circuit breakers. IEEE Transactions on Plasma Science, 33(5 I), 1576-1581.

Journal Article Type Article
Publication Date Oct 1, 2005
Journal IEEE Transactions on Plasma Science
Print ISSN 0093-3813
Publisher Institute of Electrical and Electronics Engineers
Peer Reviewed Peer Reviewed
Volume 33
Issue 5 I
Pages 1576-1581
Keywords dynamics of closure and opening, mathematical modeling, metallic vapor pressure, vacuum circuit breaker
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Additional Information Additional Information : The work for this paper was carried out under an EPSRC grant. The idea of relating contact bounce in vacuum circuit breakers to the vapour pressure is new. The phenomena occurs at very short durations and has defied experimental measurement. Mathematical modelling was therefore performed which in turn contributes significantly to the manufacturer's awareness for design purposes. (Sneider Electric, Leeds, Mr Gary Taller.)