Phaselet-Based Method for Detecting Electric Faults in 3φ Induction Motor Drives-Part I: Analysis and Development

This paper presents the analysis and development of a new method for electric fault detection in induction motor drives. The proposed method is based on extracting the magnitudes and phases of the high-frequency subband (HFSB) contents present in the d - q-axis components of the stator currents (i(d) and i(q)) in an induction motor. The desired magnitudes and phases are extracted by processing id and iq using phaselet frames that are realized by a modulated filter bank. This filter bank is designed using six digital high-pass filters, whose coefficients are determined by biorthogonal phaselet basis functions. Extracted HFSB contents provide signature information that can offer accurate and fast detection of faults. The phaselet-based electric fault detection method has been made into a procedure for digital implementation. The performance of the proposed method is evaluated offline for collected stator currents from two different induction motor drives under different operating conditions. Offline test results show accurate, reliable, and fast detection of electric faults, with minor sensitivity to the ratings, loading levels, and type and location of faults.