Rotor fault diagnosis of wound rotor induction machine for wind energy conversion system under time-varying conditions based on optimized wavelet transform analysis

On the broken rotor bar diagnosis using time–frequency analysis: ‘Is one spectral representation enough for the characterisation of monitored signals?’

“…Nevertheless, a machine operating under the existence of a fault is practically operating in time-varying conditions [51][52][53][54]. In the case of SFSA, these time-varying conditions' periodicity is designated according to the fault periodicity over the rotation of the rotor and the continuous induction of electromagnetic quantities from the stator to the rotor and vice-versa [28,[52][53][54]. Such periodicities are not always easy to track through the frequency spectra; therefore a time-frequency representation -where they are translated on a spectrogram as modulations, as demonstrated in Figs.…”

“…Nevertheless, a machine operating under the existence of a fault is practically operating in time‐varying conditions [51–54]. In the case of SFSA, these time‐varying conditions’ periodicity is designated according to the fault periodicity over the rotation of the rotor and the continuous induction of electromagnetic quantities from the stator to the rotor and vice‐versa [28, 52–54].…”

Novel Diagnostic Techniques for Rotating Electrical Machines—A Review

“…Not many papers have been published on this subject, owing to the few industrial applications of WRIMs, particularly in the past. Recently, renewed interest in WRIMs has arisen as double fed induction generators (DFIGs) for wind power generation, in which the rotor windings are fed by an electronic converter to control the active and reactive power flows from the generator to the electrical network [53,[78][79][80]. For this machine, a rotor failure is similar to a stator failure and can manifest itself in an increase in rotor resistance, a short circuit or an open circuit.…”

“…In [79], a diagnostic method based on the combination of WT and a pre-processing of rotor voltages in time-varying operations is investigated to identify rotor imbalances. The paper focuses on tracing the most significant fault frequencies in rotor voltages; since the machine-load inertia produces a damping effect on higher-order fault harmonics, the authors examined only the signature of the sideband sf s on a 5.5 kW WRIM with two pole pairs, connected with a PWM back-to-back converter on the rotor side.…”