A Novel Stator Turn Fault Detection Technique by Using Equivalent High Frequency Impedance

Stator turn fault is the most serious failure in the electrical machine drive which requires immediate detection techniques. Under such a turn fault, the fundamental change is that the high frequency (HF) impedance of the fault phase is significantly reduced due to the flux nullifying effect of the fault turns. Thus, this paper proposes a novel turn fault detection technique by using the equivalent HF impedance. It is derived by the HF voltage and current signals which are obtained by processing the phase voltages and currents with a bandpass filter. The effectiveness of the proposed is verified by extensive simulation and experimental tests on both surface mounted and interior PM machines. It is demonstrated that the performance of the proposed detection method is superior than the conventional HF current ripple based method. The investigation also confirms that the fault can be detected at an early stage by the proposed method.