Specific damage energy of dielectric materials as the universal characteristic of polymer insulation stability under the influence of surface partial discharges (phenomena, measurement, practical supplement)

To compare the stability of polymer insulation under the influence of partial discharges it is possible to use test results on the stability to surface partial discharges (SPD). These tests are organized in such a way that the discharges appear in the zone of triple conjugate (metal-air-polymer), as shown. The authors show that the energy parameter specific damage energy of dielectric Wp can be used as criteria of insulation stability under SPD influence where only part of SPD energy spent to damage of volume dielectric unit is taken into account. This characteristic depends only on dielectric properties. Only short time enough to damage the definite volume of dielectric is required in order to receive such characteristic