External PD resistance of thermoplastic and XLPE containing voltage stabilizers

Films based on a wide range of thermoplastic and XLPE (crosslinked polyethylene) including compounds containing aromatic voltage stabilizers (fluoranthene, naphthalene, pyrene, vinylnaphthalene and anthracene) were exposed to external PD (partial discharge) in dry air at 298 K. Very low molar mass PE, M/sub w/=13600 g/mol, exhibited a very low resistance towards PD. It is believed that the low concentration of interlamellar tie chains and the pronounced mechanical brittleness caused early void formation induced by the mechanical action of the plasma. PE with a higher molar mass showed a PD life that was essentially independent of molar mass, degree of crosslinking, crystallinity and crystal thickness. The added voltage stabilizers had no effect on the PD lifetime.