A New Stator Winding Inter-Turn Short Circuit Fault Detection Method For Brushless Doubly Fed Induction Machine

The brushless Doubly Fed Induction Machine (BDFIM) with high reliability and robust structure demonstrates technical and commercial advantages both as a generator and motor for variable speed drive applications. As a generator it is particularly attractive to be used in offshore wind turbines where reliability improvement and maintenance cost reduction are the key factors in wind power market growth. As a motor it can be utilized in application requiring adjustable speed operation. Inter-turn short circuit fault is one of the most frequent electrical faults in electric machines, which can also be the cause of other stator winding faults in the machine, hence its early detection can significantly reduce the maintenance cost and improve reliability. In this paper a novel fault detection method for inter-turn short circuit fault is proposed for the BDFIM based on the discrete wavelet transform of the stator winding currents. The analytical winding function method as well as the finite element analysis of an experimental D180 BDFIM is used in order to verify the proposed fault detection method.