Assessing oil paper insulation conditions by poles computed from Frequency Domain Spectroscopy

In this contribution, the dielectric dissipation factor of oil impregnated paper were monitored along with the degree of polymerization. A series of experiments have been performed under controlled laboratory conditions. Since the dielectric parameters values are geometry dependent, poles which are independent of the geometry, calculated from resistances and capacitances, were considered to evaluate the condition of oil impregnated paper insulation. A correlation has been observed between the degree of polymerisation of the paper insulation and the poles values outputted from the frequency response. From the investigations performed on new and aged oil paper samples, it was shown that poles can be regarded as insulation aging indicator.