Partial discharge characteristics on epoxy-boron nitride nanocomposite due to ageing time under high voltage stress

Abstract

Recent works show that the polymer nanocomposites have huge attractions in high voltage equipment as an insulating material due to enhancement of polymer properties. One of the main phenomena that occur in polymeric insulating material is partial discharges. Partial discharge (PD) occurrence is known as an important factor that effects and shows signs of ageing of the insulation surface which leads failure of the insulation system. PD is a localized dielectric breakdown that occurs in a small portion of solid insulation under high voltage stress. These phenomena may effects of the insulator material which cause damage because it starts from the enclosed voids. This thesis presents the experimental investigation of PD characteristics in epoxy-nanocomposites as high voltage insulating materials. The tested samples of neat epoxy, epoxy-BN 2wt% and epoxy-BN 5wt% were prepared and investigated. The combination of epoxy and Boron Nitride (BN) would produce a good match of composite for electrical insulation. It would increase the polymeric insulation performance. PD characteristics tests were carried out on each sample based on the CIGRE Method II technique under high voltage stress of ageing time process based on the IEC 60270 standard. Moreover, the surface morphology of all samples by using the Olympus SZX16 optical microscope technique after ageing time process has been investigated. FESEM analysis had been used to investigate the micrograph of the sample surface and EDX analysis used to determine the chemical elements of each sample. Based on the PD results, the higher of weight percentage with BN filler will decrease the PD magnitude, PD number and the charge of PD compared to the neat sample. PD activities affected the degradation area of the sample surfaces. It had been discovered that the higher BN of filler amount caused less degradation area.