Experiments on charge generation in cross-linked polyethylene and ethylene-propylene copolymer

To study the space charge generation in cross‐linked polyethylene (XLPE) and ethylene propylene copolymer (EPR), space charge profiles in both materials are measured using the PEA method. The experimental results demonstrated a large difference in the detected charge profiles between XLPE and EPR. We discovered that the diffusion of charge is significantly faster in EPR than in XLPE. The authors confirmed that the negative hetero charge is generated near the positive electrode in EPR when moisture coexists with acetophenone. The effects of antioxidants on the generation of hetero space charges in XLPE and EPR are also studied using XLPE and EPR samples containing different kinds of phenolic and sulfur type antioxidants. The authors discovered that hetero charge is generated in XLPE and EPR containing sulfur‐type, or sulfur‐containing phenolic, antioxidants when acetophenone is present in the material. The hetero charge generation is inferred as being caused by the combined effect between acetophenone and the component containing sulfur atoms of the antioxidants. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(1): 1–9, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20690