Improvement in the electrical performance of electrical insulation by non-linear fillers

Nonlinear conductivity in insulating materials has been achieved by the introduction of zinc oxide (ZnO), in particulate form, to these materials. This procedure results in the material retaining its insulating qualities at low electric fields but becoming increasingly conductive as the field increases, for a sufficiently high filler concentration. This paper considers the influence that this nonlinearity may have on a number of insulation degradation mechanisms in polyester resin; specifically, surface charge dissipation, electrical treeing and surface tracking.