Dielectric Properties of Alumina based Epoxy Composites for Electrical Insulation

Epoxy resin is widely used polymeric insulating material in power engineering applications including transformer and machine insulation, GIS spacers, bushing, cable terminations etc. Addition of micro and nano particles in base matrix is in common practice since last few decades aiming to improve electrical, thermal and mechanical properties of insulating material. In this paper dielectric properties of epoxy composites such as dielectric constant, dielectric loss and volume resistivity were investigated at different alumina filler loading. Experiments were performed to measure dielectric constant and dielectric loss as a function of frequency. Further DC volume resistivity was measured using high resistance meter and resistivity cell. Results indicate decrement in permittivity and dielectric loss at low filler loading of nano particles. Further, with increase in filler concentration permittivity tends to increases. In case of DC volume resistivity for all the epoxy composites resistivity is found lower than the neat epoxy resin.