DISTRIBUTION OF PARTIAL DISCHARGES IN OIL-IMPREGNATED INSULATION

This paper presents the characteristics of partial discharge activity in oil-impregnated pressboard under different test voltage stresses and frequencies. The objective is to investigate the effect of the variation of the voltage stress and the test voltage frequency to the statistical distribution of partial discharges on this particular insulation. The statistical distribution of partial discharge pattern, which is discussed here includes the mean, deviation, skewness and the kurtosis of the maximum and average discharge level. The statistical distributions of discharge current and number are also analyzed. The test results indicate that, for the conditions tested, parameter kurtosis may be used for partial discharge pattern classification purposes in such insulation configuration