Abstract

(Received: 2014/10/29 - Accepted: 2014/12/17)In this paper the presence of electric charge in two insulation of cross-linked polyethylene (XLPE) in medium voltage cables was compared using the technique of Thermally Stimulated Depolarization Currents (TSDC). Antioxidant in solid form was added to one of the insulation, and in liquid form to the other. By analyzing the TSDC measures we verified that the use of liquid antioxidant is better because the solid antioxidant creates defects that act as centers for trapping the space charge. In these centers the ionized charge, by the combined effect of temperature and electric field, is accumulated in the insulation, in addition to the charge injected from the semiconductor electrodes by the effect of high fields.