Effects of acid vapor and water vapor on corona partial discharges of stator windings

This paper discussed the effects of acid vapor and water vapor of different relative humility on corona partial discharge (PD) taken place in stator windings. Phase resolved partial discharge (PRPD) system was adopted to show the characteristics of PD. The experiment results showed that the relative humidity (RH) of vapor with different chemical properties can suppress corona discharge to certain extent. The contribution of acidic vapor is much more significant than that of the water vapor in suppressing of the corona discharges. The corona discharge tends to change into creeping on the surface of the ground wall insulation at high RH, and in this condition PD could hardly be detected.