Effect of pressure and temperature on interfacial breakdown betweentwo dielectric surfaces

摘要

Breakdown experiments were performed on slices of EPDM rubberpressed one against the other. To achieve this, an experimental jig wasdesigned so as to induce breakdown between the two slices,longitudinally along their interface. Effects of interfacial pressureand of the presence of silicone grease at the interface are taken intoaccount. Breakdown voltages are given for AC measurements. The authorsillustrate how deformations, due to high-temperature operation, canoccur in a cable joint. A relationship is also established between thisdeformation and the joint interfacial pressure, which in turns affectsthe interfacial dielectric strength. It is concluded that the dielectricstrength of an EPDM/EPDM interface is greatly affected by theinterfacial pressure. Moreover, the presence of silicone grease bothimproves (at low pressure) and limits, even if the interfacial pressureis increased (above 50 kPa), the dielectric strength of EPDM/EPDMinterfaces