Effects of α-Nucleating Agent on the Electrical Tree Growth of PP/POE Blend Cable Insulation

Polypropylene (PP) is considered to be a recyclable material for high voltage cable insulation for its higher melting point and electrical resistivity. This work focuses on the effect of a-nucleating agent content on the electrical tree growth characteristics in PP/POE blend insulation. In this paper, $a$ nucleating agent is added into iPP insulation to investigate the effect on the electrical tree growth characteristics. The crystallinity and melt temperature of the samples increase gradually as the $a$ nucleating agent content increase from 0 to 0.4 wt% while the size of spherical crystal decreases from 214.2 µm to 73.3 µm. As the $a$ nucleating agent content increase from 0 to 0.4 wt%, the partial discharge amplitude and frequency decrease gradually and the partial discharges are suppressed significantly. The length of electrical tree decreases from 0.48 mm to 0.31 mm and the accumulative damage area decreases from 0.24 mm ² to 0.09 mm ² . The study shows that the addition of 0.4 wt% of $a$ nucleating agent can regulate the crystalline morphology of the PP/POE blended insulation during the manufacturing with a slow cooling rate, and improve the electrical tree resistance of PP blended insulation.