Novel frequency-domain-based technique to detect stator interturn faults in induction machines using stator-induced voltages after switch-off

Traditionally, for medium- and high-voltage motors and generators, condition-based monitoring of stator faults is performed by measuring partial discharge activities. For low-voltage machines, negative-sequence impedance or currents are measured for the same. Such diagnostic schemes should be carefully implemented as supply voltage unbalance, manufacturing-related asymmetry, etc., also produce negative-sequence voltages. A few approaches based on motor current signature analysis have already been proposed to detect stator interturn faults. However, little or no physical insight was provided to explain the occurrence of certain harmonics in the line current or the influence of voltage unbalance on these harmonics. Also, in at least one of these papers, a large portion of the stator winding was shorted to emulate the faults. The method proposed in this paper monitors certain rotor-slot-related harmonics at the terminal voltage of the machine, once it is switched off. In the absence of supply voltage, issues such as voltage unbalance, time harmonics do not influence the measurements except as initial conditions, which is a very desirable feature when the machine is fed from an adjustable-speed drive. Satisfactory simulation and experimental results have been obtained with only about 1.5% (5/324) of the total number of turns shorted.

[1]  C.J. Dister,et al.  Using temperature, voltage, and/or speed measurements to improve trending of induction motor RMS currents in process control and diagnostics , 1998, Conference Record of 1998 IEEE Industry Applications Conference. Thirty-Third IAS Annual Meeting (Cat. No.98CH36242).

[2]  J. Penman,et al.  Detection and location of interturn short circuits in the stator windings of operating motors , 1994 .

[3]  H.A. Toliyat,et al.  A novel approach for broken rotor bar detection in cage induction motors , 1998, Conference Record of 1998 IEEE Industry Applications Conference. Thirty-Third IAS Annual Meeting (Cat. No.98CH36242).

[4]  David G. Dorrell,et al.  Analysis of airgap flux, current and vibration signals as a function of the combination of static and dynamic airgap eccentricity in 3-phase induction motors , 1995, IAS '95. Conference Record of the 1995 IEEE Industry Applications Conference Thirtieth IAS Annual Meeting.

[5]  Gabriel Kron.  Equivalent Circuits of Electric Machinery. , 1967 .

[6]  P. L. Alger,et al.  The Nature of Induction Machines , 1965 .

[7]  J. Kapler,et al.  Stator winding monitoring , 1998 .

[8]  Hamid A. Toliyat,et al.  Transient analysis of cage induction machines under stator, rotor bar and end ring faults , 1995 .

[9]  William James Premerlani,et al.  A new approach to on-line turn fault detection in AC motors , 1996, IAS '96. Conference Record of the 1996 IEEE Industry Applications Conference Thirty-First IAS Annual Meeting.

[10]  G. Joksimovic,et al.  The detection of interturn short circuits in the stator windings of operating motors , 1998, IECON '98. Proceedings of the 24th Annual Conference of the IEEE Industrial Electronics Society (Cat. No.98CH36200).

[11]  S. Williamson,et al.  Analysis of Cage Induction Motors with Stator Winding Faults , 1985, IEEE Power Engineering Review.

[12]  F. Filippetti,et al.  Induction machine stator fault on-line diagnosis based on LabVIEW environment , 1996, Proceedings of 8th Mediterranean Electrotechnical Conference on Industrial Applications in Power Systems, Computer Science and Telecommunications (MELECON 96).

[13]  Mark Sumner,et al.  A speed identifier for induction motor drives using real-time adaptive digital filtering , 1998 .

[14]  J. L. Kohler,et al.  Condition-based maintenance of electrical machines , 1999, Conference Record of the 1999 IEEE Industry Applications Conference. Thirty-Forth IAS Annual Meeting (Cat. No.99CH36370).

[15]  H. G. Sedding,et al.  Current monitoring for detecting inter-turn short circuits in induction motors , 1999, IEEE International Electric Machines and Drives Conference. IEMDC'99. Proceedings (Cat. No.99EX272).

[16]  M. Liwschitz.  Field Harmonics in Induction Motors , 1942, Transactions of the American Institute of Electrical Engineers.

[17]  Hamid A. Toliyat,et al.  A method for dynamic simulation of air-gap eccentricity in induction machines , 1996 .

[18]  Mohamed Benbouzid,et al.  Induction motors' faults detection and localization using stator current advanced signal processing techniques , 1999 .

[19]  Peter Tavner,et al.  Condition monitoring of electrical machines , 1987 .

[20]  J.L. Kohler,et al.  Alternatives for assessing the electrical integrity of induction motors , 1989, Conference Record of the IEEE Industry Applications Society Annual Meeting,.

[21]  Gojko Joksimovic,et al.  The detection of inter-turn short circuits in the stator windings of operating motors , 2000, IEEE Trans. Ind. Electron..