Influence of insulating oil on space charge formation and electrical threshold in polycarbonate with inorganic filler

Examination of the space charge accumulation and space charge profile of insulating materials is becoming increasingly important in the field of material research. polycarbonate with titanium dioxide filler (PCTiO₂) is an insulating material, which in many applications is used in combination with insulating oil. Therefore, examination of the space charge formation should include the influence of the insulating oil. For this purpose space charge measurements were made on PCTiO₂ specimens without any oil and on specimens that were stored in oil for some time. Differences in the space charge densities were observed. To confirm the penetration of the oil into the solid dielectric, polarisation current measurements and thermogravimetry were used.