Electrical Treeing Initiation in Polypropylene under Low Temperature with Different Power Frequencies

The electrical treeing processes in cross-linked polyethylene (XLPE) and PP were investigated under different temperatures. The treeing characteristics of polypropylene (PP) under low temperature with different frequencies were also investigated. The results show that the inception probability of PP at the same temperature is lower than that of XLPE. The growth rate of PP is slower than that of XLPE. With the temperature decreasing, the inception probabilities and growth rate decrease. The change of tree density with temperature is attributed to the changes of mechanical properties and oxygen. Because of the increase of number of injected charges and partial discharges, the growth rate and accumulated damage increase with the frequency increasing.