Detection and Classification of Stator Short-Circuit Faults in Three-Phase Induction Motor

Induction motors are the backbone of the industries because they are easy to operate, rugged, economical and reliable. However, they are subjected to stator’s faults which damage the windings and consequently lead to machine failure and loss of revenue. Early detection and classification of these faults are important for the effective operation of induction motors. Stators faults detection and classification based on wavelet Transform was carried out in this study. The feature extraction of the acquired data was achieved using lifting decomposition and reconstruction scheme while Euclidean distance of the Wavelet energy was used to classify the faults. The Wavelet energies increased for all three conditions monitored, normal condition, inter-turn fault and phase-to-phase fault, as the frequency band of the signal decreases from D1 to A3. The deviations in the Euclidean Distance of the current of the Wavelet energy obtained for the phase-to-phase faults are 99.1909, 99.8239 and 87.9750 for phases A and B, A and C, B and C respectively. While that of the inter-turn faults in phases A, B and C are 77.5572, 61.6389 and 62.5581 respectively. Based on the Euclidean distances of the faults, D_f and normal current signals, three classification points were set: K₁ = 0.60 x 10², K₂ = 0.80 x 10² and K₃ = 1.00 x 102. For K₂ ≥ D_f ≥ K₁ inter-turn faults is identified and for K₃ ≥ D_f ≥ K₂ phase to phase fault identified. This will improve the induction motors stator’s fault diagnosis.

Keywords
induction motor; stator fault classification; data acquisition system; Discrete Wavelet Transform