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Publication
A simple model of distribution of current over cathodes of vacuum circuit breakers
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Advisor(s)
Abstract(s)
There are several hundreds of spots operating
simultaneously on cathodes of vacuum arcs in high-power vac uum circuit breakers. In this work, the spot distribution along
the contact surface is simulated by means of an approach
that is based on the concept of surface density of spots and
represents a natural alternative to tracing individual spots.
An equation governing the evolution of the surface density
of the spots or, equivalently, the distribution of macroscopic
(averaged over individual spots) current density over the cathode
is obtained by generalizing the concept of random walk of a
single cathode spot in low-current vacuum arcs. The model
relies on empirical parameters characterizing individual spots
(the diffusion coefficient of the random motion of cathode spots
and the velocity of drift superimposed over the random motion),
which may be taken from experiments with low-current arcs,
and does not involve adjustable parameters. The model is simple
and physically transparent and correctly reproduces the trends
observed in the experiments under conditions where the cathode
arc attachment is diffuse. The distribution of the macroscopic
current density on the cathode, given by the model, represents
the boundary condition that is required for existing numerical
models of vacuum arcs in high-power vacuum circuit breakers.
Description
Keywords
Propagation Vacuum arcs Vacuum circuit breakers . Faculdade de Ciências Exatas e da Engenharia
Citation
Cunha, M. D., Wenzel, N., Almeida, P. G., Hartmann, W., & Benilov, M. S. (2019). A simple model of distribution of current over cathodes of vacuum circuit breakers. IEEE Transactions on Plasma Science, 47(8), 3462-3469.
Publisher
Institute of Electrical and Electronics Engineers