The effect of semiconductive screens and XLPE insulation combinations on electrical tree inception

Electrical tree inception tests have been carried out on different combinations of semiconductive screen (semicon) needle/XLPE insulation samples. The test programme has been designed so that it is possible to ascertain the main factors which promote or retard electrical tree inception. The results obtained have permitted predictions to be made of the most appropriate material combinations. The analysis shows that the interaction between the insulation and the semicon is highly significant and in fact dominates the performance of the selected material combination. Thus it can be concluded that by careful design and selection of semicon/XLPE combinations, samples with enhanced electrical treeing properties can be manufactured.