Comparison of laser ablation and inclined plane tracking tests as a means to rank materials for outdoor HV insulators

As the popularity of polymeric composites for outdoor high voltage (HV) use continues to increase, surface degradation through electrical discharge activity is becoming a more serious issue. In order to design composites offering improved resistance to degradation, and hence improved component lifetimes, tests need to be performed under controlled conditions in order to rank different materials. Inclined plane tracking tests are often used to determine the relative performance of various material formulations used in their construction. An alternative approach is to employ a high power laser to deposit known amounts of energy at a known rate to the sample surface. In this paper a variety of material formulations were subjected to inclined plane tracking tests as well as to laser ablation testing. The results indicate that the two test methods compare favorably and that laser ablation offers a quick and cost effective way of screening candidate material formulations, prior to more detailed study.