Influence of antioxidants on heterocharge generation in polymeric dielectrics.

The generation of space charges in polymeric dielectric materials is known to be affected by such inclusions as cross-linking by-products, antioxidants, and moisture. We reported previously that negative heterocharges in XLPE are generated in the presence of acetophenone and sulfur-containing antioxidants. In this paper we describe further experiments using samples containing DCP and three different antioxidants in order to examine the mechanism of this phenomenon. Negative heterocharges near the positive electrode were detected in samples containing both DCP and antioxidants when those samples were soaked in acetophenone. Negative heterocharges were not detected in samples containing either DCP or the antioxidant, even when the sample was soaked in acetophenone. These results demonstrate that a heterocharge is generated by the combined effect of acetophenone and the substance produced by interaction between DCP and the antioxidant. Based on the results of experiments measuring the amount of heterocharge in samples that had been heatpressed at different temperatures, the mechanism of negative heterocharge generation in polymeric dielectric material is inferred. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 172(2): 1–9, 2010; Published online in Wiley InterScience (<URL>www.interscience.wiley.com</URL>). DOI 10.1002/eej.20941 [ABSTRACT FROM AUTHOR]