To study the influence of the degree of polymerization on time-domain dielectric properties of the oil-paper insulation

a test platform of oil-paper insulation polarization current characteristics is built to test the polarization/depolarizing current of oil-paper insulation samples consisted of different initial moisture

initial acid and different initial degrees of polymerization. After that the corresponding time domain dielectric spectroscopy could be drew. Finally the result is fitted to get formula of DP and peak time constant. The results show that DP won’t influence time domain dielectric characteristics of oil-paper insulation when DP changes as a single variable

so in this situation DP can’t be used as aging characteristic. Only when polar molecules such as water and acid diffuse into the inside of insulation paper and form an interface polarization

the influence of DP can be reflected. When water or acid value content increases

the time domain dielectric spectroscopy generally goes up left with larger peak

lower peak time constant and better goodness of fitting. It’s necessary to reference the moisture content

acid content and other polar molecules content of oil-paper insulation when using the aging kinetic model based on DP to make residual life assessment of transformer.