Impurities in XLPE cable resins

This paper presents results on an impurity analysis of various insulation and semiconducting shield resins made by four manufacturers and used for power cables. Three different strand-blocking materials used to fill the conductor interstices were also analyzed. The measurements were performed by neutron activation on many samples taken from several batches and for several elements. The resins are compared to identify and quantify cleaner materials, since it is well known that impurities play an important role in the initiation and growth of water trees. Cleaner insulation and conductor shield resins can be found nowadays, but insulation shield resins are still of low quality. Strand-blocking materials are found to be heavily contaminated, which is inconsistent with the trend to use cleaner components for extruded cables.<>