Study on improving of interfacial microstructure and breakdown strength of polyethylene for power cables

Special additives were used to modify the semiconducting layer chemically. In this paper, the relationship between the crystal orientation angle of the PE interface and the E_b has been deduced theoretically. The results of microstructure analysis showed that the modified semiconducting layer affected the crystal orientation angle of the PE interface, and revealed the formation of a very thin diffusion layer during the thermal process, and the suppression of the agglomeration of carbon particles in the semiconducting layer. The results of model cable specimens and treeing tests proved that additives AB₂ possessed the best modifying effect, in that they enhanced the breakdown strength E_b (1% Weibull distribution) of PE by 89% and the AC breakdown strength E_b by 40%, and could increased the treeing inception voltage of PE by 39%