Electrical aging of fluoropolymer cable insulation materials induced by partial discharge

Abstract

This study investigates AC electrical aging induced by partial discharge (PD) in fluoropolymer cable insulation materials, namely fluorinated ethylene propylene (FEP) and perfluoroalkoxy (PFA), with the cross-linked polyethylene (XLPE) serving as the reference material. Utilizing a specialized electrical aging setup and comprehensive surface characterization techniques, we compared the aging behavior of FEP and PFA to that of XLPE under identical electrical discharge conditions. Over a three-week aging process, the stability of phase-resolved partial discharge (PRPD) patterns for FEP and PFA suggested minimal changes in surface chemistry and roughness, unlike XLPE. FTIR and Raman spectroscopy results confirmed minimal changes in the surface chemistry of FEP and PFA, while microscopic and profilometric analyses demonstrated notably fewer PD-induced alterations on their surfaces. These findings suggest a gradual aging effect on the electrical insulating properties of fluoropolymers, likely due to their resilient carbon-fluorine bonds, contrasting with the immediate and significant erosion and by-product formation observed in XLPE upon PD exposure.