Abstract:

Based on the theory of magnetohydrodynamics, considering the influence of space turbulence, a large space full dynamic arc model of multiphysics simulation coupled medium voltage DC air circuit breaker is built to simulate the short-circuit breaking arc of medium voltage DC air circuit breaker. The results show that during the short-circuit arc breaking process of medium voltage DC air circuit breakers, the transfer of arc roots will cause fluctuations in arc voltage, arc current and arc power, and then the arc roots will exhibit stickiness. The arc column area between the grids will generate reverse arc phenomena. The extinguishing speed of the arc is positively correlated with the magnitude of the applied magnetic field, but the trend of change does not show a linear relationship, which can provide a theoretical basis for solving the hard problem of consciousness of breaking short circuit current of medium voltage DC air circuit breaker.

Key words: medium voltage DC air circuit breaker, short-circuit breaking, arc root sticking, arc reverse movement