Modeling of Plasma Dispersion Process in Vacuum Interrupters During Postarc Interval Based on FEM

This paper presents a novel finite-element modeling of interelectrode plasma dispersion process inside a vacuum interrupter (VI) prototype. A new set of coupled equations considered for the plasma simulation process consisting of the Stefan-Maxwell diffusion equations, collision and interaction between particles considerations, and Coulomb integral for conductivity calculation of plasma are utilized to give a better understanding from complicated vacuum plasma dispersion process inside a VI. Using SolidWorks software, an exact 3-D schematic of the prototype is drawn and imported to the proper finite-element method software. Considering suitable boundary conditions and proposed plasma equations set, including 10 kV/μs. The ramp function as a transient recovery voltage inserted to the contacts, the model is dynamically simulated, and the derived results have been discussed in detail. In continue, postarc current waveform is derived using the Maxwell equations. This result is compared to a practical-based common model which is named the Andrews-Varey transition model. The derived postarc waveforms are compared in a table. The similarities of results, for example, postarc time (difference between two models is less than 8%) or maximum value of postarc current (difference <;7.5%), ensure the accuracy of the new proposed plasma modeling strategy.