Off-line and on-line pd measurements on induction motors fed by power electronic impulses

Partial Discharge (PD) off- line and on-line measurements are required to prevent early failures on low voltage induction motors fed by inverter drives. Conventional methods use commercial Digital Scopes to visualize simultaneously the waveform of the applied impulsive voltage and the acquired PD pulses, as well as appropriate solutions to attenuate power electronic voltage impulses. A new approach is proposed in this paper, relying upon a Phase-Resolved PD (PRPD) pattern, which constitutes a simple and efficient tool for PD activity detection in adjustable speed drives. Off-line PD measurements were done on low voltage induction motors fed by a voltage impulse generator and detecting PD Inception Voltage (PDIV) on each phase. Then, PD on line measurements were carried out using a commercial PWM inverter and showing interesting correlation between off-line and on-line tests. All the measurements were performed using antenna sensors, achieving excellent sensitivity.

[1]  G.C. Stone,et al.  New tools to determine the vulnerability of stator windings to voltage surges from IFDs , 1999, Proceedings: Electrical Insulation Conference and Electrical Manufacturing and Coil Winding Conference (Cat. No.99CH37035).

[2]  Davide Fabiani,et al.  Aging acceleration of insulating materials for electrical machine windings supplied by PWM in the presence and in the absence of partial discharges , 2001, ICSD'01. Proceedings of the 20001 IEEE 7th International Conference on Solid Dielectrics (Cat. No.01CH37117).

[3]  G. Stone,et al.  Inverter-fed drives: which motor stators are at risk? , 2000 .

[4]  M. Fenger,et al.  The impact of surge voltage rise-time on PD inception voltage in random wound motors of different designs , 2001, 2001 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.01CH37225).

[5]  Davide Fabiani,et al.  Evaluation of corona-resistant magnet wires through partial discharge and space charge measurements , 2001, Proceedings: Electrical Insulation Conference and Electrical Manufacturing and Coil Winding Conference (Cat. No.01CH37264).

[6]  A. Cavallini,et al.  A technique for defect investigation in pulse-controlled motors through partial discharge measurements , 2004, Conference Record of the 2004 IEEE International Symposium on Electrical Insulation.

[7]  Weijun Yin,et al.  Failure mechanism of winding insulations in inverter-fed motors , 1997 .

[8]  A. Cavallini,et al.  A UHF Technique for Advanced PD Measurements on Inverter-Fed Motors , 2008, IEEE Transactions on Power Electronics.