The effect of an oil-paper interface parallel to an electric field on the breakdown voltage at elevated temperatures

Results are reported for the measurement of the electrical breakdown location in the vicinity of an oil-paper interface over the temperature range from room temperature to 150 degrees C. The data indicated that the electrical breakdown occurred at the interface from 15% to 43% of the time, depending on the details of the particular set of measurements. A theoretical analysis shows that this experimental result is consistent with the electric-field enhancement, the area over which the enhancement occurs, and the spread in the breakdown voltages for nominally identical tests.<
>