Research on Moisture Assessment of Oil-Paper Insulated Bushing Based on Polarization and Depolarization Current

摘要

High-voltage bushing is an important part of the operation of transformer equipment. In order to accurately and effectively evaluate the moisture condition of the bushing, this paper uses the polarization and depolarization current (PDC) non-destructive measurement method to do it. In the current research, the characteristics of loss peaks and curve fluctuations of tanδ-f curve can judge whether the bushing is evenly damp, but it lacks the judgment of the high moisture position of the internal damp. This paper uses oil-paper samples of different moisture content to make a preliminary qualitative exploration of PDC measurement methods. Then the polarity reversal method is used to judge the bushings with different moisture conditions, Combined with the migration characteristics of hydrolyzed ions in the oil-paper insulation, it is analyzed to verify the effectiveness of the method.