NEW TOOLS FOR DIAGNOSTIC MEASUREMENTS
ON ELECTICAL ROTATING MACHINES
Michael Krüger © OMICRON
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
Annual Convention 2014 – Eilat, Israel
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Sources of Insulation Damages
Source: Brütsch et al. "Insulation Failure Mechanisms of Power Generators", DEIS July/August 2008
Annual Convention 2014 – Eilat, Israel
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Electrical Failures
A: small voids on edge
H: Discharges in Cooling Duct
B: delamination: winding – main insulation
I: Delamination of Insulation in Elbow
C: delamination of tape layers
J: endwinding surface discharge - contamination
D: treeing in layers
K: Insufficient Spacing, Tracking
E: broken strands
L: Connection area between slot corona protection
and endwinding corona protection
G: micro voids
F: slot discharge, semicon paint abrasion
Annual Convention 2014 – Eilat, Israel
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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
Annual Convention 2014 – Eilat, Israel
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Insulation Resistance Measurement
Measurement
Time
U-VWE
60 s
Measurement
Current
25.9809 nA
Time
U-VWE
600s
Current
3.7637 nA
PI = 25.98 / 3.76 = 6.9
Annual Convention 2014 – Eilat, Israel
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Time Constant
dry
humid
Annual Convention 2014 – Eilat, Israel
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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
Annual Convention 2014 – Eilat, Israel
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Dielectric Response
Combination of PDC and FDS
Polarisations- und
Depolarisationsstrom
PDC
Frequency Domain
Spectroscopy
FDS
1
Tan Delta
Current [nA]
100
1
1
Zeit [s]
1000
0,001
0,1
1000
Frequenz [Hz]
Transformation
Verlustfaktor
1
0,001
0,001
Annual Convention 2014 – Eilat, Israel
Frequency [Hz]
1000
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1.
f > 0,1 Hz
 Frequency Domain
2.
f < 0,1 Hz
 Time Domain
3.
Transformation of the Time
Domain Data into the
Frequency Domain
FDS / PDC Measurement
Annual Convention 2014 – Eilat, Israel
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FDS / PDC Measurement with 2 Channels
Annual Convention 2014 – Eilat, Israel
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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
Annual Convention 2014 – Eilat, Israel
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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
Annual Convention 2014 – Eilat, Israel
ΔTan-Delta Test according to IEC 60894
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Test Setup C-Tan-Delta Measurement
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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
Annual Convention 2014 – Eilat, Israel
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PD Fault in Head Windings
VATech Hydro Austria
Annual Convention 2014 – Eilat, Israel
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Cross-Coupling in
the Stator Winding
•Capacitive
Capacitive
•Capacitive
&
&Coupling
Coupling
Inductive
Inductive
Coupling
Coupling to
to the
the coils
coils
•Inductive
•Capacitive
& Inductive
of
ofother
the
same
two phases
phase
Coupling
•Capacitive
Coupling
•Inductive
Coupling
E
E
H
•3
2
1
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
•PD
•CORE
L1
L2
L3
neutral
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15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
36
35
34
33
32
PD Measurement
with 3 Synchronous Channels
3PARD
Inner PD source
L1>L2>L3
L2
L1
Interne TE Quelle in
der L1 Wicklung
L2
L3
L3
L1
•timeframe
1 µs
3PARD = 3 Phase Amplitude Related Diagram
Annual Convention 2014 – Eilat, Israel
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Synchronous 4-Channel PD Measurement
Phase U1-U2
Annual Convention 2014 – Eilat, Israel
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Channel 1 = U1
Annual Convention 2014 – Eilat, Israel
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Channel 2 = U2
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Channel 3 = V1
Channel 4 = W1
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Synchronous 4-Channel PD Measurement
without Filtering
U1
U2
V
W
Annual Convention 2014 – Eilat, Israel
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3PARD
U1
U2
V
3PARD = 3 Phase Amplidude Related Diagram
or in this case:
3 Channel Amplitude Related Diagram
Annual Convention 2014 – Eilat, Israel
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Synchronous 3-Channel PD Measurment
with 3PARD Filtering - Cluster A
U1
V
U2
A
Annual Convention 2014 – Eilat, Israel
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Synchronous 3-Channel PD Measurment
with 3PARD Filtering - Cluster B
U1
V
Annual Convention 2014 – Eilat, Israel
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B
U2
Simultaneous Measurement of PD,
Capacitance and Tan Delta
Annual Convention 2014 – Eilat, Israel
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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
Annual Convention 2014 – Eilat, Israel
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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
Annual Convention 2014 – Eilat, Israel
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Measurement Setup
Coupling Capacitors
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PD Coupler
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PD Instruments
connected to
the Couplers
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PD Measurement without Filtering
Annual Convention 2014 – Eilat, Israel
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PD Measurement with 3PARD Filtering
Annual Convention 2014 – Eilat, Israel
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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
Annual Convention 2014 – Eilat, Israel
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Generator
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Dielectric Response with FDS
Annual Convention 2014 – Eilat, Israel
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Dielectric Response with PDC
Annual Convention 2014 – Eilat, Israel
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Drying of the Winding with 250A
Annual Convention 2014 – Eilat, Israel
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Drying of the Winding with 250A
Annual Convention 2014 – Eilat, Israel
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Winding Resistance Measurement with 100A
0.05Ω
0.045Ω
0.04Ω
0.035Ω
0.03Ω
U
V
0.025Ω
W
0.02Ω
0.015Ω
0.01Ω
0.005Ω
0.0Ω
Annual Convention 2014 – Eilat, Israel
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Fault: Broken Soldered Joints
Annual Convention 2014 – Eilat, Israel
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Measurement of the Dielectric Response
Before and After Drying (FDS - tanδ)
tanδ
[%]
before drying
after drying
Annual Convention 2014 – Eilat, Israel
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Measurement of the Dielectric Response
Before and After Drying (FDS - Capacitance)
c‘ [F]
before drying:
C’ (1mHz) / C (50Hz) = 14.3
after drying:
C’ (1mHz) / C (50Hz) = 2.5
before drying
after drying
Annual Convention 2014 – Eilat, Israel
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Measurement of the Dielectric Response
Before and After Drying (PDC)
before drying
after drying
Annual Convention 2014 – Eilat, Israel
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Dismounted
Rotor
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Dirt in the End Windings
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Dirt in the End Windings
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After Cleaning the End Windings
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PD Test Phase U up to 6400V
Breakdown at 6400V
Annual Convention 2014 – Eilat, Israel
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Location of the Breakdown (Smoke with 2A)
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Lower or Upper Bar ? (I = 2A)
0.01A
2.04A
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Cutting out the Faulty Coil
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New Soldering Joints
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Insulated Soldering Joint
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Repaired Winding
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FDS Phase U – Before and After Repair
before repair
after drying
before repair
and drying
after repair
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FDS Phase U – Before and After Repair
before repair
and drying
before repair
after drying
after repair
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michael.krueger@omicron.at
Questions and Remarks?