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Microprojection heating caused by the approach of a microparticle
Author(s) -
Ejiri Haruki,
Kumada Akiko,
Hidaka Kunihiko,
Donen Taiki,
Tsukima Mitsuru
Publication year - 2017
Publication title -
ieej transactions on electrical and electronic engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.254
H-Index - 30
eISSN - 1931-4981
pISSN - 1931-4973
DOI - 10.1002/tee.22558
Subject(s) - microparticle , joule heating , radius , circuit breaker , voltage , joule (programming language) , materials science , current (fluid) , electrode , mechanics , electrical engineering , nanotechnology , chemistry , physics , engineering , optics , composite material , computer science , computer security , efficient energy use
Vacuum circuit breakers have been widely used in a medium‐voltage class. In vacuum circuit breakers, late breakdowns sometimes occur after current interruptions. These late breakdowns are triggered by the microparticles and they occur when the microparticles collide with the electrode. In this paper, joule heating caused by field emission enhanced by the approach of a microparticle is simulated using the finite element method. It is turned out that the prolate hemi‐spheroidal microprojection can be vaporized by joule heating when h < 100 nm and w / h < 0.1, where h and w are the semimajor axis and semiminor axis of the microprojection, respectively. The temperature at the center of the microprojection increases exponentially with vr p 2 , where v and r p are the speed and the radius of the microparticle, respectively. It is important to remove the large microparticles in order to prevent late breakdowns caused by the microparticles.