Investigation of space charge and conduction current in additivated XLPE

DC charging-discharging current measurements associated to space-charge distribution observations enable to discuss the conduction and trapping mechanisms, as function of electrical stress, in XLPE compounds for HVDC cables. The effect of additives increasing conductivity is explained on the basis of the hypotesized conduction mechanisms, i.e. ionic and electronic depending on field intensity. Likewise. the accumulation of heterocharge at the electrode-polymer interface is associated to interaction of intrinsic and extrinsic charges.