Influence of conductive particles on the breakdown conditions of air gaps in the presence of corona

The operating conditions of corona-electrostatic separators, of various electroprecipitators, and of other similar devices are influenced by the size and shape of the particles which pass through the inter-electrode air-gap. The presence of corona affects the movements and the charge of the particles, and hence modifies the breakdown threshold. The numerical analysis of the electric field using a charge simulation program, enabled a crude evaluation of the effects. Nevertheless, experiments with various spherical and cylindrical particles were necessary to fully-understand the phenomena. The electrode arrangement consisted of a matrix of high-voltage corona-emitting points situated above a grounded plate electrode. Both the computational results and the experimental data demonstrated that the presence of particles in air-gaps affected by corona discharges has a more important influence on the dielectric strength than in the case of a charge-free electric field