Motion Characteristics and Lift-Off Behavior of Metallic Particles in AC GIS Under Single and Continuous Vibration Excitations: A Simulation Study

Mechanical disturbances and sustained enclosure vibration can promote lift-off and motion of free metallic particles in AC gas-insulated switchgear (GIS). A three-dimensional electrostatic-field and particle-tracing model was used to examine spherical aluminum, iron, and copper particles under power-frequency voltage and prescribed single-burst or continuous vibration. The calculations include contact charging, charge retention during free flight, gas drag represented by the Stokes approximation, and inelastic random collisions. Lift-off was defined numerically by a normalized inward gap η ≥ η_tol = 10−4 together with positive inward-normal velocity. In vibration-free cases, transient thresholds were within about 1% of analytical force-balance estimates; this is an internal consistency check, not independent validation. For 0.25 mm radius particles, four-phase mean first-loss thresholds at 0 g were about 379, 649, and 693 kV RMS for aluminum, iron, and copper, and at 0.75 g about 266, 457, and 488 kV RMS. In the retained single-burst results, positive-voltage thresholds are shown through 1.25 g and zero-voltage first loss at 1.5 g; the 1.0 g and 1.25 g values require reconciliation with an independent reduced calculation and are not treated as verified thresholds. Continuous 50 Hz calculations at 750 kV RMS used a 0.2 s window and five random seeds at each of four nonzero-vibration phases. The mean maximum flight heights at 0 g were about 1.9, 0.15, and 0.12 mm; at 1.2 g the means were about 3.0, 0.86, and 0.61 mm. These are model-dependent results: representative Reynolds-number estimates exceed the creeping-flow range, and matched experimental validation and observation-time convergence remain outstanding.