Detection and classification of turn fault and high resistance connection fault in permanent magnet machines based on zero sequence voltage

Health monitoring and fault detection are becoming more and more important in electrical machine systems due to the increasing demand for reliability. Winding turn fault is a common fault in permanent magnet machines which can cause severe damages and requires prompt detection and mitigation. High resistance connection (HRC) fault which result in phase asymmetry may also occur but does not require immediate shutdown. Thus, apart from the fault detection, the classification between the two faults is also required. In this paper, a new technique for detecting and classifying turn fault and HRC fault by utilizing both the high and low frequency components of the zero sequence voltage is proposed. The dependence on the operating conditions is minimized with the proposed fault indicators. The effectiveness of fault detection and classification has been verified by extensive experimental tests on a triple redundant fault tolerant permanent magnet assisted synchronous reluctance machine (PMA SynRM). The robustness of the turn fault detection in transient states and under no load conditions has also been demonstrated.