Impact of Test Voltage Magnitude on FDS Characteristics of Oil-Paper Insulation with Different Aging Conditions

Frequency Domain Spectroscopy (FDS) is a method to know the transformer oil-paper insulation condition by measuring the dielectric parameters in a frequency range. As expressed by numerous research results, moisture and aging condition has a significant influence. In addition, the FDS result is also affected by electric field through electrode polarization or Garton effect in low frequency, which may mislead the judgment of the aging condition. However, this influence is seldom considered in previous research. In this paper, study on the impact of voltage level during the oil-paper insulation aging process is shown. The FDS test of power transformer oil-paper insulation system in different aging conditions (accelerated thermal aging from new sample to aged samples of several tens of days),…