Factors affecting creepage and clearance distances of polymer insulators in coastal and marine electrical equipment

The influence of ionic liquid contaminants on tracking behavior of four typical polymeric insulants is measured and recorded in terms of electrode separation and voltage. The insulants treated are Bakelite, polyvinyl chloride (PVC), polymethyl methacrylate (PMMA) and polystyrene (PS). Investigations to relate time-to-track and distance between electrodes are introduced. Both bakelite and PS materials have low Martens temperature. Therefore, they have more tendency to track, leaving carbonized traces on the surface. PVC and PMMA have better tracking behaviors. They evolve gaseous products of decomposition which foster extinction of the arc. Soaking the insulating specimens in diesel engine oil delayed failure effectively, presumably by preventing wetting of the surface