Space charge distribution measurements in XLPE and EPR subjected to a uniform DC field

Space charge distributions in crosslinked polyethylene (XLPE) and ethylene propylene rubber (EPR) subjected to dc fields of /spl sim/25 and 50 kV/mm in a dry environment at room temperature is investigated. To simulate the insulation of high voltage cable, the specimens were equipped with semicon electrodes. Aging with dc field generates considerably more space charge in EPR than in XLPE and the local electric stresses associated with the accumulated space charge can be significant. EPR develops heterocharge at both stress levels whereas XLPE develops heterocharge at the lower but homocharge at the higher stress.