Partial discharge characteristics of natural rubber blends nanocomposites as high voltage insulating material

Abstract

Polymeric materials are widely used in power system apparatus insulation especially for high voltage cables. Partial discharge (PD) however, has always been a predecessor to major faults and problem within this field. Recent works show that natural rubber (NR) and polyethylene blend produces a good composite match for the purpose of electrical insulation. The paper aims is to investigate the PD characteristics of NR and linear-low density polyethylene (LLDPE) nanocomposite blends when exposed to high voltage stress for an aging time of 3 hours. Nano- sized fillers of silica (SiO2) and Titania (TiO2) (used as filler in this work) were prepared by extrusion and moulding process. PD tests were carried out on each sample based on CIGRE Method II technique. Lab VIEWTM software was used to analyze the filtered voltage measurement to deduce PD pulse magnitude and number of PD occurrence, respectively. Morphological analysis using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy were also performed in order to obtain better comprehensive result. Results revealed correlation between amount of filler and discharge activities. Sample NR-LLDPE blends filled with 4% nano-sized TiO2 tend to suppress PD activities within 3 hours of PD aging test with the lowest PD occurrence number recorded. Meanwhile, the highest PD number was detected from composition NR-LLDPE blends without filler. Surface morphological analysis from SEM and EDX shows that degradation occurs for all samples. Thus, by considering their PD characteristics, NR-LLDPE nanocomposite can be considered as an alternative electrical insulating material.