Effects of trap density on space charge suppression of block polypropylene/AI2O3 composite under high temperature.

Block polypropylene (BPP) is an eco-friendly material that has a good potential for cable insulation because of its high melting point and excellent electrical properties. To further improve the electrical insulation properties of BPP, 1 wt% Al2O3 nanoparticles were added by melt blending to BPP. The electrical properties of the BPP/Al2O3 composite were measured at 25 and 70 °C. The results show that the trap density increases by 3.2 times that of unfilled BPP. The conduction current in BPP and BPP/Al2O3 composite decreased at 25 and 70 °C. The electrical breakdown strength of the composite also increases compared to BPP. Space charge accumulation is significantly suppressed in the composite at 70 °C. The results indicate that the improvements in electrical properties, especially the space charge suppression in the composite, can be attributed to the higher trap density. Permittivity and dielectric loss show little effect on temperature. The permittivity of the composite shows a slight increase which can be attributed to the higher permittivity of the Al2O3 nanoparticles. [ABSTRACT FROM AUTHOR]