The effect of voltage, temperature and morphology on electrical treeing in polyethylene blends

The dominant experimental parameter controlling the electrical tree growth rate was temperature. All materials show a significant increase in the average growth rate as the temperature was increased between 20°C and 60°C. The magnitude of this change was three orders of magnitude for the BPEQ (LDPE quenched sample) but much less, only two orders of magnitude for the blend samples (LB series). The effect of temperature on the tree growth is more pronounced at higher applied voltages, due to the fact that the applied voltage for rapid runaway tree growth decreases with increasing temperature. The morphology of the polymer also appears to modify the electrical treeing characteristics, particularly at higher temperatures. The addition of a linear chain HDPE (20%) to LDPE (80%) reduces the tree growth rate. The degree to which the growth rate decreases, appears to follow the increasing morphological disorder of the blend