A Study on the Space Charge Characteristics of AC Sliced XLPE Cables

Cross-linked polyethylene (XLPE) cables are widely used in power systems due to their excellent electrical and mechanical properties. Space charge is an important factor in cable aging and breakdown. At present, XLPE cables in the power system are mainly ac XLPE cables, so it is necessary to study the space charge characteristics under ac voltage. In this paper, an electro-thermal aging platform for XLPE cable was built and a 10-kV cable was aged. XLPE slices were obtained from the aging cable and ac space charge experiments were carried out on the XLPE slices at different stages of aging. The trap energy levels were calculated and the effects of different electric fields on the ac space charge characteristics were compared. The experimental results show that the trap energy level increases with the aging process and the non-averaged electric field is a necessary condition for charge migration.