Modelling the Effects of Temperature and Moisture Ingress on Capacitance and Dissipation Factor Measurements within Oil Impregnated Paper Transformer Bushings
The majority of power transformer high voltage bushings today are of the condenser oil impregnated paper (OIP) type. The ingress of moisture, through the deterioration of the bushing over time, can result in a significant reduction in life and is a major failure mode of these bushings. Currently, the measurement of capacitance and dissipation factor is the most common method used to assess the bushing condition. This paper studies the effects of moisture and temperature on the dielectric properties of a bushing . Simulations are made using COMSOL Multiphysics software to analyse the associated dielectric changes and the resultant capacitance and dissipation factor variation.