INFLUENCE OF DUST PARTICLES ON DC DISCHARGES IN SYMMETRICAL AIR GAPS

Breakdown and corona are investigated in dealt and dust-polluted rod-r od air gaps varying gap length, rod radius and voltage polarity. It is shown that similar to previous results under impulse voltages, dust p ollution can significantly reduce the DC breakdown voltage values of s uch gaps which depends upon electrode radius, gap length and voltage p olarity. These factors should therefore be considered prior to the des ign and application of air insulation in desert regions, where sand an d dust storms can occur frequently. Possible mechanisms which control the observed behaviour are explained in detail.