Space charge suppression of polyethylene induced by blending with ethylene-butyl acrylate copolymer

High-voltage direct current (HVDC) power cables have been paid more attention due to the big issue concerning the main insulation materials. The residues in the industrial production process will cause space charge generation and accumulation in the materials, which has become one bottleneck to limit the development of power cables up to higher voltage levels. In this paper, the LDPE matrix was modified by three types of ethylene-butyl acrylate (EBA) copolymers (1.0 wt%) with different polarities (BA content) via melt blending to optimize the space charge behavior of the LDPE insulation. The micromorphology and structure of the blends are examined by polarized light microscope and differential scanning calorimetry. The space charge distribution is tested by the pulsed electro-acoustic method. The trap level is studied by the thermally stimulated current. The results show that EBA introduces more deep traps and decreases the shallow traps. The medium-polar EBA (16% BA content) can effectively suppress charge accumulation, and have the same suppressed effect on XLPE/EBA blends. This study will provide important insights into the design and development of advanced HVDC power cable applications.