Comprehensive Monitoring of Field Winding Short Circuits for Salient Pole Synchronous Motors

An interturn insulation failure in the field winding of synchronous motors is a common problem that can lead to degradation in performance and accelerated wear of motor components. Existing offline tests for detecting this fault are known to be unreliable and inconvenient to perform, as they require motor disassembly. Online monitoring based on airgap flux monitoring has been proven to be successful, but could lack sensitivity for cases where the number of turns per pole is large. In addition, field winding turn shorts can be intermittent depending on the centrifugal force and could be unobservable at standstill or under an steady state operation. Therefore, monitoring of the turn faults under standstill and starting conditions with high sensitivity and without motor disassembly is desirable. In this paper, the detection of field winding short circuits for salient pole synchronous motors based on an airgap search coil under the starting transient, and new methods for standstill testing without motor disassembly are proposed. Two-dimensional finite element analysis and experimental testing on a 30-kW motor are given to verify the claims made. It is shown that the proposed set of tests can provide sensitive and reliable detection of field winding short circuits under standstill and starting conditions.

[1]  Sang Bin Lee,et al.  Influence of Blade Pass Frequency Vibrations on MCSA-Based Rotor Fault Detection of Induction Motors , 2017, IEEE Transactions on Industry Applications.

[2]  Mohamed A. El-Sharkawi,et al.  Detection of shorted-turns in the field winding of turbine-generator rotors using novelty detectors-development and field test , 1996 .

[3]  F.C. Trutt,et al.  Detection of A-C machine winding deterioration using electrically excited vibrations , 1999, Conference Record of the 1999 IEEE Industry Applications Conference. Thirty-Forth IAS Annual Meeting (Cat. No.99CH36370).

[4]  M. Sulowicz,et al.  Comparative investigation of fault indicators for synchronous machine failures , 2014, 2014 International Conference on Electrical Machines (ICEM).

[5]  D. R. Albright.  Interturn Short-Circuit Detector for Turbine-Generator Rotor Windings , 1971 .

[6]  R. T. Hindmarch,et al.  Rotor winding short detection , 1986 .

[7]  Li Yonggang,et al.  Diagnosis of Short Circuit Faults Within Turbogenerator Excitation Winding Based on the Expected Electromotive Force Method , 2016, IEEE Transactions on Energy Conversion.

[8]  F.C. Trutt,et al.  Condition monitoring of brushless three-phase synchronous generators with stator winding or rotor circuit deterioration , 2001, Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248).

[9]  Li Yonggang,et al.  Diagnosis of Rotor Winding Interturn Short-Circuit in Turbine Generators Using Virtual Power , 2015, IEEE Transactions on Energy Conversion.

[10]  J. S. Hsu,et al.  Shaft signals of salient-pole synchronous machines for eccentricity and shorted-field-coil detections , 1994 .

[11]  Isidor Kerszenbaum,et al.  Utilization of Repetitive Surge Oscillograph (RSO) in the detection of rotor shorted-turns in large turbine-driven generators , 2011, 2011 Electrical Insulation Conference (EIC)..

[12]  R. L. Stoll,et al.  Method of detecting and modelling presence of shorted turns in DC field winding of cylindrical rotor synchronous machines using two airgap search coils , 1988 .

[13]  Jose A. Antonino-Daviu,et al.  Advanced Rotor Fault Diagnosis for Medium-Voltage Induction Motors Via Continuous Transforms , 2016, IEEE Transactions on Industry Applications.

[14]  Prabhakar Neti,et al.  A New Robust Method To Detect Rotor Faults in Salient-Pole Synchronous Machines Using Structural Asymmetries , 2008, 2008 IEEE Industry Applications Society Annual Meeting.

[15]  Robert J. Marks,et al.  Localization of winding shorts using fuzzified neural networks , 1995 .

[16]  Blake Lloyd,et al.  Finite Element Analysis of Turbine Generator Rotor Winding Shorted Turns , 2012, IEEE Transactions on Energy Conversion.

[17]  Jinkyu Yang,et al.  Automated Detection of Rotor Faults for Inverter-Fed Induction Machines Under Standstill Conditions , 2011 .

[18]  G. C. Stone,et al.  Detecting Turn Shorts in Rotor Windings: A New Test Using Magnetic Flux Monitoring , 2013, IEEE Industry Applications Magazine.

[19]  Ian Culbert,et al.  Electrical insulation for rotating machines : design, evaluation, aging, testing, and repair , 2003 .

[20]  Isidor Kerszenbaum.  Inspection of Large Synchronous Machines: Checklists, Failure Identification, and Troubleshooting , 1996 .