WATER AND THERMAL STRESS INFLUENCE ON DIELECTRIC SPECTRUM OF POLYETHYLENE FOR POWER CABLES
DOI:
https://doi.org/10.36801/Keywords:
thermal stress, dielectrical spectrum, energy cablesAbstract
Dielectric properties – real and imaginary parts of complex permittivity – were analyzed by dielectric spectroscopy in the frequency range 10-2 – 106 Hz and for temperatures from 30 – 70 oC, for samples cut from tree retardant crosslinked polyethylene (TRXLPE) and conditioned in three different ways: in ambient air, immersed in water for a week and, then, accelerated thermally aged for a month. One goal of this paper was to emphasize the electric stability of TRXLPE. Thus, by using dielectric spectroscopy tests, we analyzed the influence of water and heat stress on the dielectric properties of polyethylene for medium voltage power cable insulations. Another purpose of the paper was to prove once again that the dielectric spectroscopy is a high performance tool, allowing the characterization of the dielectric materials used in the insulating systems of cables, in broad frequency and temperature ranges, and, consequently, the understanding of the behavior of these materials in different conditions of operation (temperature variations, humidity and thermal degradation).
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