A New Strategy to Detect and Localize Interturn Short-Circuit Fault in Medium-frequency-Transformer of Dual-Active-Bridge Converter

The windings of medium-frequency transformer (MFT) in the dual-Active-Bridge (DAB) converter are at huge risk of interturn (ITT) short-circuit fault due to rapid switching of high excitation voltages. Thus, it is crucial to quickly detect the online failure of winding at incipient level avoiding catastrophic conditions. Thus, the proposed work analyses DC link current of DAB converter under ITT fault and proposes a new online detection and localization strategy based on its variation for 4% of ITT fault. In the proposed work, the average and RMS of fault indicator obtained from difference of secondary and primary side DC link current are employed to detect and localize the ITT fault in MFT of the DAB converter. The presented work is supported via ANSYS simulation and validated for the hardware prototype of the DAB converter. Index Terms-Medium-frequency transformer (MFT), interturn (ITT) short-circuit fault, DAB converter, DC link current.