Space-charge characteristics in polyethylene for DC power cable

By utilizing the laser-induced-pressure-pulse technique, space-charge behavior in modified high-density polyethylene (m-HDPE) during the polarity reversal and the effects of semiconducting layer were investigated. In m-HDPE with metal electrodes on both sides, homo space-charge was accumulated near the anode and hetero space charge was formed just after polarity reversal. On the other hand, in sample with a metal electrode on one side and a semiconducting electrode on the other side the space charge injected from the metal electrode migrated toward the counter electrode just after field application. After the polarity reversal, the charge injection from metal electrode predominates over the existing space charge and hetero space charge was not formed. It seems that the application of the semiconducting electrode affected the space charge characteristics in m-HDPE.