1. NEW TOOLS FOR DIAGNOSTIC MEASUREMENTS ON ELECTICAL ROTATING MACHINES
Michael Krüger © OMICRON

2. New Tools for Diagnostic Measurements on Rotating Electrical Machines
Introduction
Insulation Resistance and the Polarisation Index (PI)
Dielectric Response
Capacitance and Dielectric Dissipation (Power) Factor
Partial Discharge (PD) Measurement
Online PD Measurements on a 330MVA Hydro Generator
PD Location
Case Study - Measurements on a Hydro Generator

3. Sources of Insulation Damages
Source: Brütsch et al. "Insulation Failure Mechanisms of Power Generators", DEIS July/August 2008

4. Electrical Failures A: small voids on edge
B: delamination: winding – main insulation
C: delamination of tape layers
D: treeing in layers
E: broken strands
G: micro voids
F: slot discharge, semicon paint abrasion
H: Discharges in Cooling Duct
I: Delamination of Insulation in Elbow
J: endwinding surface discharge - contamination
K: Insufficient Spacing, Tracking
L: Connection area between slot corona protection and endwinding corona protection

5. Electrical Measurement Methods I

6. Electrical Measurement Methods II

7. New Tools for Diagnostic Measurements on Rotating Electrical Machines
Introduction
Insulation Resistance and the Polarisation Index (PI)
Dielectric Response
Capacitance and Dielectric Dissipation (Power) Factor
Partial Discharge (PD) Measurement
Online PD Measurements on a 330MVA Hydro Generator
PD Location
Case Study - Measurements on a Hydro Generator

8. Insulation Resistance Measurement
Time
Current
U-VWE
60 s nA
Measurement
Time
Current
U-VWE
600s nA
PI = / 3.76 = 6.9

9. Time Constant
dry
humid

10. New Tools for Diagnostic Measurements on Rotating Electrical Machines
Introduction
Insulation Resistance and the Polarisation Index (PI)
Dielectric Response
Capacitance and Dielectric Dissipation (Power) Factor
Partial Discharge (PD) Measurement
Online PD Measurements on a 330MVA Hydro Generator
PD Location
Case Study - Measurements on a Hydro Generator

11. Dielectric Response Combination of PDC and FDS
Diagnosis of Tranformer On-load Tap Changers
29 November 2006
Dielectric Response Combination of PDC and FDS
Polarisations- und DepolarisationsstromPDC
Frequency Domain Spectroscopy FDS
Current [nA]
Zeit [s]
Trans-
formation
Frequency [Hz]
Verlustfaktor
0,001 1
1000
100
Frequenz [Hz]
Tan Delta
0,1
f > 0,1 Hz  Frequency Domain
f < 0,1 Hz  Time Domain
Transformation of the Time Domain Data into the Frequency Domain
Results in frequency domain are directly displayed.
Results from time domain are at first transformed to frequency domain and then displayed.
Time domain data (polarization current) can be shown as well.
Paper 4 -

12. FDS / PDC Measurement

13. FDS / PDC Measurement with 2 Channels

14. New Tools for Diagnostic Measurements on Rotating Electrical Machines
Introduction
Insulation Resistance and the Polarisation Index (PI)
Dielectric Response
Capacitance and Dielectric Dissipation (Power) Factor
Partial Discharge (PD) Measurement
Online PD Measurements on a 330MVA Hydro Generator
PD Location
Case Study - Measurements on a Hydro Generator

15. Measurement of Dielectric Losses
Dielectric losses in insulating systems (tan )
conducting losses (tan C)
polarization losses (tan P)
partial discharge losses (tan PD)
tan  = tan C + tan P + tan PD
Dielectric losses: tan  = f (U)
Tip-Up Test according to IEEE 286
ΔTan-Delta Test according to IEC 60894

16. Test Setup C-Tan-Delta Measurement

17. New Tools for Diagnostic Measurements on Rotating Electrical Machines
Introduction
Insulation Resistance and the Polarisation Index (PI)
Dielectric Response
Capacitance and Dielectric Dissipation (Power) Factor
Partial Discharge (PD) Measurement
Online PD Measurements on a 330MVA Hydro Generator
PD Location
Case Study - Measurements on a Hydro Generator

18. PD Fault in Head Windings
28/11/2006
PD Fault in Head Windings
VATech Hydro Austria

19. Cross-Coupling in the Stator Winding
28/11/2006
CORE L2 L1 L3
neutral E H PD
Capacitive Coupling
Inductive Coupling
Capacitive & Inductive Coupling
Capacitive & Inductive Coupling to the coils of the same phase
Capacitive & Inductive Coupling to the coils of other two phases
Cross-Coupling in the Stator Winding
CORE 19

20. PD Measurement with 3 Synchronous Channels
28/11/2006
PD Measurement with 3 Synchronous Channels
3PARD
Inner PD source L1>L2>L3 L1 L2 L3 L2
Interne TE Quelle in der L1 Wicklung L3 L1
timeframe 1 µs
3PARD = 3 Phase Amplitude Related Diagram 20

21. Synchronous 4-Channel PD Measurement Phase U1-U2

22. Channel 1 = U1

23. Channel 2 = U2

24. Channel 3 = V1 Channel 4 = W1

25. PD Calibration Matrix

26. Synchronous 4-Channel PD Measurement without FilteringV W

27. 3PARD U1 U2 V 3PARD = 3 Phase Amplidude Related Diagram
or in this case:
3 Channel Amplitude Related Diagram

28. Synchronous 3-Channel PD Measurment with 3PARD Filtering - Cluster AV U2 A

29. Synchronous 3-Channel PD Measurment with 3PARD Filtering - Cluster BV B U2

30. Simultaneous Measurement of PD, Capacitance and Tan Delta

31. Simultaneous Measurement of PD, Capacitance and Tan Delta on U-VWE
C-tanδ und PD Levels + PRPD at 23 Voltage Levels in approx. 6 Minutes

32. New Tools for Diagnostic Measurements on Rotating Electrical Machines
Introduction
Insulation Resistance and the Polarisation Index (PI)
Dielectric Response
Capacitance and Dielectric Dissipation (Power) Factor
Partial Discharge (PD) Measurement
Online PD Measurements on a 330MVA Hydro Generator
PD Location
Case Study - Measurements on a Hydro Generator

33. Measurement Setup
Coupling Capacitors

34. PD Coupler

35. PD Instruments connected to the Couplers

36. Calibration

37. PD Measurement without Filtering

38. PD Measurement with 3PARD Filtering

39. New Tools for Diagnostic Measurements on Rotating Electrical Machines
Introduction
Insulation Resistance and the Polarisation Index (PI)
Dielectric Response
Capacitance and Dielectric Dissipation (Power) Factor
Partial Discharge (PD) Measurement
Online PD Measurements on a 330MVA Hydro Generator
PD Location
Case Study - Measurements on a Hydro Generator

40. PD Measurement on a 6kV Generator

41. PD Measurement on a 6kV Generator
HV U
Star point X
Coupling at the end winding into V and W

42. PD at End Corona Protection

43. PD at End Corona Protection

44. New Tools for Diagnostic Measurements on Rotating Electrical Machines
Introduction
Insulation Resistance and the Polarisation Index (PI)
Dielectric Response
Capacitance and Dielectric Dissipation (Power) Factor
Partial Discharge (PD) Measurement
Online PD Measurements on a 330MVA Hydro Generator
PD Location
Case Study - Measurements on a Hydro Generator

45. Generator

46. Dielectric Response with FDS

47. Dielectric Response with PDC

48. Drying of the Winding with 250A

49. Drying of the Winding with 250A

50. Winding Resistance Measurement with 100A

51. Fault: Broken Soldered Joints

52. Measurement of the Dielectric Response Before and After Drying (FDS - tanδ)
before drying
after drying

53. Measurement of the Dielectric Response Before and After Drying (FDS - Capacitance)
before drying: C’ (1mHz) / C (50Hz) = 14.3
after drying: C’ (1mHz) / C (50Hz) = 2.5
c‘ [F]
before drying
after drying

54. Measurement of the Dielectric Response Before and After Drying (PDC)
before drying
after drying

55. Dismounted Rotor

56. Dirt in the End Windings

57. Dirt in the End Windings

58. After Cleaning the End Windings

59. After Cleaning the End Windings

60. Identification of Phase U with a Contactless Voltage Checker (300V AC on U1)

61. Ultrasonic Measurement – No US-Signal !

62. PD Test Phase U up to 6400V
Breakdown at 6400V

63. Location of the Breakdown (Smoke with 2A)

64. Lower or Upper Bar ? (I = 2A)

65. Cutting out the Faulty Coil

66. New Soldering Joints

67. Insulated Soldering Joint

68. Repaired Winding

69. FDS Phase U – Before and After Repair
before repair after drying
before repair and drying
after repair

70. FDS Phase U – Before and After Repair
before repair and drying
before repair after drying
after repair

71.
Questions and Remarks?