Electrical properties for diagnosis of sulfide-tree growth in cables under dc stress

Electrical properties, that is, AC electric strength and DC conductivity, are measured at different aging times in cable models immersed in sea water with hydrogen sulfide and supplied at two voltage levels. Test conditions are studied in order to favour growth of electrochemical, or sulfide, trees. Cable models have copper conductor and polyethylene insulation. It is shown that both electric strength and conductivity significantly vary with tree-growth time, providing tools for cable degradation diagnosis.