Inclined-plane tests of textured silicone rubber samples

The shank regions of a polluted polymeric insulator are vulnerable to thermal damage from partial arcs. To alleviate this problem, it has recently been proposed to contour the polymeric surface with regular patterns of protuberances in order to reduce both the leakage current density and electric field strength in such regions, and by the same means to achieve an increase in creepage length. The performance in inclinedplane tests of samples prepared with various types of textured pattern, and a range of sizes of hemispherical protuberances, are described, along with results for non-textured plane-surface samples for comparison. A remarkable improvement is achieved by such texturing in the satisfaction of the standard test criteria, and in limiting surface discharge activity and reducing the tracking and erosion of the sample.