Partial discharge (PD) is one of the key factors in insulation failure of inverter-fed traction motor. Due to the high steepness of impulse with broad frequency range

PD under continuous impulses is not easy to be detected by a conventional PD detection system. In this paper

impulse current sensor (ICS) has been applied to develop a new PD detection system and the wavelet packet method is used to extract the PD signals. Moreover

the coil of traction motor is used as the test sample. The statistics of test results of PD signals show that PD signals can be successfully identified by the new PD detection system. Finally

issues about the influence of voltage and frequency of square wave pulses on discharge number

maximum discharge and mean amplitude of PD signals are discussed.