Space Charge Characteristics of CB/LDPE Composites at Different Temperatures

Abstract

Space charge accumulation in the insulation is considered to be a bottleneck for further improvement of the HVDC cable voltage level. In this paper, CB/LDPE composites with a small doping content (0.03 wt%) were fabricated by using the melt blending method. Space charge characteristics of LDPE and CB/LDPE films were measured at different temperatures by pulsed electro-acoustic method, and the trap characteristics were measured by thermally stimulated current method for both films. Electric field distortion rate and the value of trap level were calculated. Experimental results indicate that, the space charge accumulation and electric field distortion at different temperatures in CB/LDPE films were obviously improved compared with the LDPE films, which is more pronounced at high temperatures. Deep traps introduced by CB nanoparticles is considered to be the key to suppress space charge injection, which is of great significance for further research and development of HVDC cable insulation materials.