Characterization of dielectric walls of capacitors

This work presents the preliminary results of a study that proposes the development of capacitors with similar or better performance in terms of reliability and partial discharges (PD) level than their oil-impregnated counterparts. It presents the comparison of several configurations and technologies of layered dielectric films capacitors impregnated with a commercial polymeric resin, with the aim to improve the properties of its inner dielectric wall. To find a suitable match between the different dielectric film arrangements and technologies with the polymeric resin used, tests on different sample configurations were carried out. These tests also covered the impact of the surface treatment prior to impregnation and the final enhancement of dielectric properties of the system due to the encapsulating polymeric resin. To ensure a reliable fabrication process, the Vacuum Pressure Impregnation (VPI) technique was used. The results show that rough polypropylene (PPR) films with prior surface treatment and set in polymeric resin may be the best candidate to compete with current technologies to carry out oil-free capacitors