Electrical Aging Markers for Low-Voltage Cable Insulation Wiring Nuclear Power Plants

This paper presents some preliminary test results of electrical property measurements on XLPE insulations used at NPPs. These cables were aged under thermal and radiation stresses: in order to obtain significant results in a reasonable time, the dose rate and the temperature chosen were higher than the values usually found inside NPPs. Electrical measurements have been performed through dielectric spectroscopy and polarization/depolarization current. First results show significant variations of the electrical properties of aged cables that can be correlated to insulation aging. In particular, the real part of the permittivity increases noticeably with aging along the entire frequency range and the imaginary part of the permittivity shows polarization peaks at the lower frequency considered for the analysis.