Space charge and conductivity characteristics of CB/XLPE nanocomposites

In order to improve the DC dielectric properties of cross-linked polyethylene (XLPE) insulation materials, carbon black (CB)/ XLPE nanocomposites were prepared with the melt blending method. The pulsed electro-acoustic (PEA) method was used to measure the space charge distribution of XLPE and CB/XLPE nanocomposites. The relationship between the DC electrical conduction and the applied electric field strength of each material was measured under several constant temperatures. The research results show that the amount of space charges significantly reduces when a small quantity of CB was added into XLPE. The ability of composites to inhibit space charges is strong when the CB content is 1 phr. It was found that the electrically conductive properties of XLPE present nonlinear characteristics under lower electrical field intensity. The electrical conductivity significantly increases with temperature. The electrical conductivity of the nanocomposites with CB is almost a constant value under the electrical field below 20 kV/mm, and the effect of temperature on the DC electrical conductivity obviously decreases, when temperature goes up. The addition o CB into the XLPE can effectively inhibit the internal space charge accumulation and improve the DC conduction characteristics of the composites.