Numerical simulation on fault arc characteristics of medium voltage air medium switchgear

Based on magnetohydrodynamic theory, this paper establishes a two-dimensional axisymmetric model of a fault arc inside an enclosed medium-voltage (MV) air-insulated switchgear. Using COMSOL Multiphysics, the Navier–Stokes and Maxwell equations are coupled to simulate the temperature field, gas flow field, arc energy, and arc voltage. The results illustrate the temperature distribution and pressure variation during the arc burning process. Arc temperature is found to be proportional to the current variation. During unstable burning, arc movement direction changes. The gas flow velocity depends on the volume force acting on it; a greater resultant force from the pressure gradient and Lorentz force leads to a higher arc velocity. Pressure measurements at the arc center and chamber wall indicate a continuous pressure rise during arc burning, culminating in an increase of ∼350 kPa. Under unstable arc conditions, the arc voltage and energy oscillate and deviate from proportionality to the current. These findings provide practical implications for arc fault management and enclosure design in MV switchgear systems.