A novel nonlinear coating for suppression of metallic particle motion in GIS

To satisfy the increased need to suppress metallic particle motion in compact Gas-Insulated-Switchgear (GIS), a novel coating with nonlinear resistivity was developed. The current density as a function of electric field (J-E) and dielectric constant of the nonlinear coating were evaluated. Electrical field analysis using the measured J-E data indicates that the nonlinear coating can reduce the field enhancement between metallic particles and the coating sufficiently to suppress particle motion compared to a dielectric coating. Experiments in a coaxial GIS bus duct geometry indicate that the nonlinear coating increases the lift-off electric field of metallic particles on the internal surface of GIS enclosure with reduced statistical dispersion in the lift-off field relative to a dielectric coating.