Influence of nano-doped LDPE cable insulating materials on the insulation and thermal conductivity properties

Abstract

Insulation and thermal conductivity performances are two important factors which restrict the development of high voltage cable to high level. The composite materials of low density polyethylene (LDPE) doped with nano SiO 2 and nano Al 2 O 3 respectively were prepared through the method of melt blending. The section surface morphology of the samples was researched by field emission scanning electron microscope (FESEM). The resistance of voltage, corona discharge properties under direct current (DC) voltage, and thermal conductivity as a function of temperature were investigated. The results indicated that the dispersion of nanosized particles in LDPE is uniform and the compatibility of the two phases is well. The DC breakdown voltage of all the composites with different proportion of doped nanosized particles is increased compared to the pure LDPE, as well as the thermal conductivity at different temperature. Especially, when the mass fraction of SiO 2 is 2 %, the breakdown voltage is increased by 32 %, and the coefficient of thermal conductivity is raised steadily in the meantime.