The correlation between partial discharge characteristics and space charge accumulation under AC voltage

Partial discharge (PD) occurrence and change of pattern were measured and simultaneously the space charge accumulation was measured under AC voltage using modified Pulsed Electro Acoustic (PEA) method at the same measuring system. In order to investigate the space charge effect in PD as phase angle varied, space charge was measured at every 18/spl deg/ of one period. From the result of experiment, the change of space charge accumulation at a certain phase angle resulted in the change of PD current at that phase angle. This result suggests that the change of space charge accumulation is the direct factor of PD characteristics.