The effect of moisture on heterocharge formation in XLPE

Space charge profiles were measured in XLPE specimens cross-linked at different temperature. Negative hetero-charges were detected n the vicinity of positive electrode in specimens cross-linked at temperature above 180°C. After the decomposition products of DCP were removed, the hetero-charge disappeared and was not detected even after the specimens were soaked in acetophenone. The space charge profiles were measured also in XLPE containing anti-static agent. The negative hetero-charge was detected more clearly in the specimen containing the antistatic agent than in non-added specimen. Though the hetero-charge disappeared after the decomposition products were removed, it was detected again after the specimen was soaked in acetophenone. The hetero-charge creation in non-added XLPE was supposed to be due to the combined effects of decomposition products of DCP and the small amount of moisture in XLPE.