In Situ Microtomography of Electrical Tree Propagation in Stress-Whitened Eco-Friendly Cable Insulation Under High Voltage

This proposal aims to determine the propagation mechanisms of electrical trees in stress-whitened cable insulation, by performing in situ microtomography on samples under high voltage. Electrical trees are hollow channels that form within polymers under very high electrical fields. The studied material is a polypropylene-based compound, which is a more sustainable alternative to conventional insulation. This material exhibits stress whitening under mechanical stress, caused by a sub-micron cavitation process resulting in scattering of visible light. The effect of stress whitening on electrical pre-breakdown phenomena is not known. This proposal will study the growth dynamics when tree branches reach stress whitening-induced voids. Further, any self-healing effects from localized heating during tree growth, resulting in melting and collapsing of voids and branches, will be studied. This will aid in increasing the reliability and lifetimes of eco-friendly high-voltage cables.