Classification of Fault Severity in Induction Machine Systems Based on Temporal Convolutions and Recurrent Networks

Abstract

Detection and severity identification of mechanical and electrical faults by means of noninvasive methods such as electrical signatures of induction machine have attracted much attention in recent years. Since operating conditions of machines and severity of faults in incipient stages influence the amplitude of fault index in the fault detection process, diagnosing fault occurrence and severity can be more complicated. In this study, an efficient method for fault detection and classification in induction machine based on deep neural networks is introduced. The introduced method applies the long short-term memory (LSTM) and fully convolutional neural networks (FCNs) in a conjoined manner. The authors use the FCN architecture for feature extraction from the time-series signal and augment it with LSTM to improve classification performance. This structure has not been previously applied for fault severity detection in induction machine systems. The authors avoid manual feature engineering and, by eliminating the preprocessing phase, directly use time series of electrical signals for fault detection and classifications. The experimental results have been carried out in different fault severities and loads. The analysis of the results and comparison with other deep and classical methods show that the faulty cases can be separated based on severity and load levels with a high accuracy (98.92%), which shows that the adopted architecture is successful in automatically extracting discriminative features from the signal.

Asymmetrical Fault Detection in Induction Motors Through Elimination of Load Torque Oscillations Effects in the Slight Speed Variations and Steady-State Conditions

“…The analytical signal obtained in (9) has been used to generate synthetic signals in MATLAB environment (Fig. 2.a).…”

“…steady-state condition Fig. 2a shows an analytical signal at a sampling frequency of 5 kHz for 12 seconds according to (9). In this signal, asymmetry fault and LTOs are also applied.…”

“…Finally, by combining ( 5) and ( 8), the synthetic signal of stator current (is_AF_LTO), which covers both RAF and LTOs, can be obtained as (9).…”

“…Several strategies have been used for the detection of mechanical and electrical faults in electrical machines in recent years such as acoustic emission analysis [2], acoustic signature analysis [3][4], flux-based detection , air gap analysis [40] vibration signature analysis [6], thermal analysis [7][8], neural networks [9], motor current signature analysis [10][11][12], etc. The motor current signature analysis (MCSA) method can be mentioned as one of the simple and cost-effective strategies [13][14][15].…”