Analysis of dielectric breakdown in power cables using 2D and 3D tomography

The occurrence of a water tree or electrical tree is identified as the main phenomenon in the degradation in solid isolations of electric energy distribution cables. Water tree evolution can lead to dielectric breakdown of the isolation layer and, consequently, to the failure of the isolated cable and the interruption of the electric energy supply. The understanding of the morphology evolution of this phenomenon is necessary for the development of analysis methods and to prevent collapse in the polymeric insulation of the cables. This work demonstrates the application of X-ray tomography as a tool for the morphology study of the paths of insulated cable breakdown formed in crosslinked polyethylene (XLPE) and ethylene propylene rubber (EPR) and also the technique of accelerated induction of the electrical tree and breakdown path in the laboratory.