No abstract

No abstract

No abstract

Polymer nanocomposites have been used for various important industrial applications. The preparation of high density polyethylene composed with Na-montmorillonite nanofiller using melt compounding method for different concentrations of clay-nanofiller of 0%, 2%, 6%, 10%, and 15% has been successfully done. The morphology of the obtained samples was optimized and characterized by scanning electron microscope showing the formation of the polymer nanocomposites. The thermal stability and dielectric properties were measured for the prepared samples. Thermal gravimetric analysis results show that thermal stability in polymer nanocomposites is more than that in the base polymer. It has been shown that the polymer nanocomposites exhibit some very different dielectric characteristics when compared to the base polymer. The dielectric breakdown strength is enhanced by the addition of clay-nanofiller. The dielectric constant (εr) and dissipation factor (Tan δ) have been studied in the frequency range 200 Hz to 2 MHz at room temperature indicating that enhancements have been occurred in εr and Tan δ by the addition of clay-nanofiller in the polymer material when compared with the pure material.

Insulation system in high voltage power equipment plays an important role for the reliability of the electric power system. So, it is necessary to assess its performance to prevent any sudden interruption in the power system. Partial discharge (PD) in solid dielectrics could occur due to the presence of a cavity or a crack within the insulating material which could be formed during manufacturing, installing or/and operating conditions. Since internal cavities are the main source of the PD activities, they can lead to causing deterioration of the insulation system and consequently a complete failure may be occurred. In this paper, PD measurement and simulation are performed on a rubber insulating material with variable cylindrical cavity diameters. High-frequency current transformer (HFCT) technique is introduced for PD measurement. Therefore, a PD simulation model is developed using COMSOL Multiphysics program interlinked with Matlab software in order to investigate the influence of cavity geometry on the PD behavior in insulating material. Both measured and simulated results indicate that PD magnitude is strongly depending on changing the cavity size inside the insulating material. The results show a good agreement between experimental and simulated data outputs in terms of maximum PD magnitude.