81 / 2024-04-11 10:39:11

Field Enhancement and Vacuum Breakdown Caused by Micro-Particles Induction in High Voltage

Vacuum breakdown, Micro-particles, Micro-morphology, Fractal geometry, Arbitrary Lagrangian-Eulerian method(ALE), Metal vapor

   The objective of this paper is to investigate the phenomena of field enhancement and microparticles (MPs) induced breakdown under high voltage. The withstand voltage of vacuum interrupters (VIs) is improved through power frequency conditioning, and the micro-topography of the electrode under saturated conditions is established using a fractal model to obtain the maximum micro-electric field intensity. Initially, the instantaneous collision velocities of metal MPs are calculated, considering the material strength equation, state equation, and thermal evaporation process during collisions. The arbitrary Lagrangian-Eulerian (ALE) method is introduced to simulate the high-speed impact of MPs on the electrode, revealing different behaviors when MPs of different radii collide with the metal electrode at various speeds. The results reveal that the conditioned electrode surface exhibits traces of melting, along with the presence of craters and protrusions. Furthermore, experimental findings and calculations demonstrate that MPs cluster and collide with the electrode surface, generating metal vapor. This vapor subsequently diffuses into the electrode gap, joining with the metal vapor concentration emanating from anode evaporation to form a conductive channel. This channel emerges within tens of microseconds, and the metal vapor deposits completely within a few milliseconds.

   The experimental and calculation results will be presented in the full paper.