Abstract: In this paper,three typical defect models are fabricated by using generator stators in actual operation.Partial discharge（PD） characteristics of the three typical defects at different applied voltages are studied by a pulse current method.Based on the defects fabrication method and test process in this paper,the results show that the slot defect has the lowest PD initiation voltage（PDIV）.The discharge pattern has a sharp rise at the beginning of the negative half cycle of power frequency voltage.The PDIV of the void defect is the highest,the PRPD pattern has obvious symmetry,and the discharge phase distribution is the widest.The end-winding discharge stator bar has obvious polarity effect,and the discharge activity of negative half cycle of power frequency voltage is more intense.The aging phenomenon of the stator bar insulation is very obvious with the extension of the pressurization time.The average discharge capacity increases,and the repetition of the discharge increases first and then decreases.The experimental results provide necessary experimental data for the insulation monitoring and fault diagnosis of generator stator.