Electrical breakdown and degradation measurements

Polymers can withstand extremely high electric fields, in excess of 1000 MV m^-1 yet low fields of a few MV m^-1 may eventually cause breakdown in some polymer-insulated systems. Apparently identical insulating systems may, when tested, breakdown at widely differing voltages, or, in service, survive for widely differing periods. The talk will aim to identify the different physical mechanisms responsible for breakdown and degradation in polymers and briefly review some of the methods used for their characterization. Comments will be made on techniques used to assess the life of high-voltage polymeric power cables