Evaluation of Cable Aging by Water Extraction of Soluble Ions
The major concern for all dielectric users is the aging of electrical insulation. This is especially true for high-voltage cable insulation, where aging results in changes in the material properties. A specific problem encountered with high-voltage cables is a degradation phenomenon known as treeing which is particularly detrimental to cable lifetime in the presence of water and impurities. It is also obvious that the presence of impurities in an insulation will reduce its electric breakdown strength. In a previous study1, it was shown that cable insulations contain several ppm of various impurities and additives, some of which were ionized (see Table 1). It was also observed that aging generally leads to an increase in the impurity contents2 caused by contaminant diffusion from the heavily contaminated semiconducting shields. Ions are certainly not welcome in any insulation system and it is of the utmost importance to know and control their contents.
KeywordsNeutron Activation Analysis Irganox 1035 Cable Insulation Contaminant Diffusion Electric Breakdown Strength
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