Abstract:
Kraft paper is one of the most commonly used
insulation in transformers and cables. Impregnation with
transformer grade mineral oil is done to improve the electrical
properties of the paper. Voltage endurance coefficient (n) is
used to estimate the performance characteristics of the
insulation paper aging. In this paper, a comparative study is
done to estimate the endurance coefficient using conventional
V-t curve method and Damage Equalization Method (DEM).
The endurance coefficient is also known as the power law
coefficient which is used in the V-t curve method to
characterize the insulation aging. The unknown power law
coefficient is also obtained from known values of step durations
and stresses for each sample till its breakdown under DEM.
Various types of AC Breakdown tests were performed on cable
insulation of different ages obtained from a local
manufacturer.
