In the present paper, the aging of stator bar insulation of generator is investigated based on the characteristics of partial discharge pulse distribution and statistical parameters, such as skewness and kurtosis. Although the changes of partial discharge distributive parameters and the statistical parameters mentioned above with aging time is not identical in different bars subjected to various stresses, a similar law is that the skewness of Hqn(/spl phi/) profile in all of specimens aged changes from positive into negative with aging time increasing. It is discussed the correlation of skewness with various type of defects in insulation. A new phenomenon is observed that the peaks of the Hn(/spl phi/) profile occur at 45/spl deg/ and 135/spl deg/ in bar insulation unaged, 0/spl deg/ and 180/spl deg/ in the bar insulation experienced moderate aging time., 90/spl deg/ and 270/spl deg/ in the bar insulation experienced longer aging duration, respectively. Although PD parameters mentioned above do not predict the lifetime of stator bar insulation of generator and evaluate insulation condition, they do give the useful information on defects in bar insulation with mica/epoxy.
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