TRANSFORMER DIAGNOSIS
Dipl.-Ing. Dr. Michael Krüger © 2006
© OMICRON
11/6/2014
Page: 1
Tap Changer
Accessories
Vessel & Oil
Bushings
Core
Winding
Frequency in %
Sources of Faults
Source: Cigre_WG 12-05 „An international survey on failures in large power transformers in service“, Electra No. 88, 1983
© OMICRON
04.12.200411/6/2014
Page: 2
Gas-in-Oil Analysis Type of Fault Partial Discharge Discharge with low Energy Discharge with high Energy Thermal Fault T<300°C Thermal Fault T<700°C Thermal Fault T>700°C Source: Möllmann, A. u.a. „IEC/VDE Standards für flüssige Isolierstoffe zur Diagnostik von Transformatoren und Wandlern“, ETG Fachbericht 87: Diagnostik elektrischer Betriebsmittel, Berlin 2002 © OMICRON
04.12.200411/6/2014
Page: 3
Tests for Diagnosis (Fault Location) •Winding resistance and OLTC test •Practical examples for winding ratio, excitation current, leakage reactance •FRSL •Capacitance and dissipation factor •FRA
© OMICRON
04.12.200411/6/2014
Page: 4
Universal Transformer Test System Power Amplifier 15-400Hz •Up to 2000A, 2kV AC / 400A DC •Measurement of •Ratio •Complex Impedance •Resistances • …...
C-Tanδ δ-Prüfsystem
© OMICRON
04.12.200411/6/2014
Page: 5
Testing OLTC
© OMICRON
04.12.200411/6/2014
Page: 6
On-load tap changer principle (1) Voltage Selector
Commutating Resistors
Diverter Switch
© OMICRON
04.12.200411/6/2014
Page: 7
On-load tap changer principle (2) Voltage Selector
Commutating Resistors
Diverter Switch
© OMICRON
04.12.200411/6/2014
Page: 8
On-load tap changer principle (3) Voltage Selector
Commutating Resistors
Diverter Switch
© OMICRON
04.12.200411/6/2014
Page: 9
On-load tap changer principle (4) Voltage Selector
Commutating Resistors
Diverter Switch
© OMICRON
04.12.200411/6/2014
Page: 10
On-load tap changer principle (5) Voltage Selector
Commutating Resistors
Diverter Switch
© OMICRON
04.12.200411/6/2014
Page: 11
On-load tap changer principle (6) Voltage Selector
Commutating Resistors
Diverter Switch
© OMICRON
04.12.200411/6/2014
Page: 12
On-load tap changer
© OMICRON
04.12.200411/6/2014
Page: 13
Measurement of the static resistance values of: 1) all internal contacts (diverter switch contacts + tap selector switch + connection clamps) + 2) the winding resistance © OMICRON
04.12.200411/6/2014
Page: 14
New voltage selector contact
© OMICRON
04.12.200411/6/2014
Page: 15
Voltage selector switch in a good condition Widerstand V-Mp 285.00 280.00
KEMA
270.00 265.00
OMICRON 1…21 Ref. Temp. OMICRON 21…1 Ref. Temp.
260.00 255.00 250.00 245.00 240.00 235.00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Widerstand [mΩ ]
275.00
Stufen
© OMICRON
04.12.200411/6/2014
Page: 16
Influence of the Temperature
Maschinentransformator 27kV/400kV 1100MVA
1. Measurement: 20°C Last Meas.:
© OMICRON
23°C
04.12.200411/6/2014
Page: 17
Influence of the Temperature 0.165Ω
235 +RTWinding (Tap) 2 R(T2 ) = R(T1 ) Beispiel : R(23°) = R (20°) *1.012 235 + T1 Delta =1.2%
0.16Ω
A UP A DOWN B UP B DOWN C UP C DOWN
0.155Ω 0.15Ω 0.145Ω 0.14Ω 000
005
010
015
020
025
030
Taps
© OMICRON
04.12.200411/6/2014
Page: 18
Faulty voltage selector contact
© OMICRON
04.12.200411/6/2014
Page: 19
Defective Voltage Selector
© OMICRON
04.12.200411/6/2014
Page: 20
Defective Tap Selector
Starke Verrußung durch Erwärmung und Ablagerungen © OMICRON
04.12.200411/6/2014
Page: 21
Resistance U-Mp R L1 (referred to 20°C)
700.0
650.0
600.0 mOhm
R L1 1974 R L1 20.2.02 1...19 RL1 20.2.02 19…1
550.0
500.0
450.0 0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Taps
© OMICRON
04.12.200411/6/2014
Page: 22
100MVA 220/110 kV V R L2 (referred to 20°) 650.0 630.0 610.0 590.0
mOhm
570.0 R L2 1974 550.0
R L2 20.2.02 1…19 R L2 20.2.02 19…1
530.0 510.0 490.0 470.0 450.0 0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Taps
© OMICRON
04.12.200411/6/2014
Page: 23
100MVA 220/110 kV W R L3 (referred to 20°) 630.0 610.0 590.0
mOhm
570.0 R L3 1974
550.0
R L3 20.2.02 1…19 530.0
R L3K 20.2.02 19…1
510.0 490.0 470.0 450.0 0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Taps
© OMICRON
04.12.200411/6/2014
Page: 24
Winding Resistance U-Mp After Repair Resistance L1 650.0 630.0 590.0 Factory Measurement OMICRON 1…19 OMICRON 19…1
570.0 550.0 530.0 510.0 490.0 470.0 450.0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
Resistance [mΩ]
610.0
Taps
© OMICRON
04.12.200411/6/2014
Page: 25
Delta R for U-Mp „UP“-„DOWN“ Resistance Differenz L1 Up-Down 40.0
20.0
Before repair
10.0 0.0
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
-10.0 1
Resistance [mΩ]
30.0
-20.0 -30.0 Taps Resistance Differenz L1 Up-Down 6.0
After repair
2.0 0.0 -2.0
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
-6.0
2
-4.0 1
Resistance [mΩ]
4.0
Taps
© OMICRON
04.12.200411/6/2014
Page: 26
Cleaning effect of OLTC movement R Winding (Tap)
0.2 Ohm 0.19 Ohm
A UP A DOWN B UP B DOWN C UP C DOWN
0.18 Ohm 0.17 Ohm 0.16 Ohm 0.15 Ohm 0.14 Ohm 0
5
10
15
20
Taps
R Winding (Tap)
0.2 Ohm 0.19 Ohm
A UP A DOWN B UP B DOWN C UP C DOWN
0.18 Ohm 0.17 Ohm 0.16 Ohm 0.15 Ohm 0.14 Ohm 0
5
10
15
20
Taps
© OMICRON
04.12.200411/6/2014
Page: 27
Increased contact resistance on a diverter switch in phase A R Winding (Tap)
0.18 Ohm 0.175 Ohm 0.17 Ohm 0.165 Ohm 0.16 Ohm 0.155 Ohm 0.15 Ohm 0.145 Ohm 0.14 Ohm 0.135 Ohm 0.13 Ohm
A UP A DOWN B UP B DOWN C UP C DOWN
0
2
4
6
8
10
12
Taps
© OMICRON
04.12.200411/6/2014
Page: 28
Tap Changer in Delta
© OMICRON
04.12.200411/6/2014
Page: 29
Tap Changer in Delta
DC
A
∆ U=0
© OMICRON
04.12.200411/6/2014
Page: 30
Measurement of a Winding 27 kV - 17 kA with 100A Test Current
Meas. Result =700µΩ µΩ
© OMICRON
04.12.200411/6/2014
Page: 31
Measurement of „Low Ohmic“ Windings
© OMICRON
04.12.200411/6/2014
Page: 32
Analysis of the Transient Switching Behavior of the Diverter Switch
© OMICRON
04.12.200411/6/2014
Page: 33
Transient signal of one switching procedure in detail
Ripple
α
Slope
1 = Diverter switch commutates from the first tap to the first commutating resistor 2 = The second commutationg resistor is switched in parralel 3 = shorting of the second commutating resistor and commutating to the second tap 4 = Charging of the additional windings
© OMICRON
04.12.200411/6/2014
Page: 34
Diagnosis of the diverter switch
© OMICRON
04.12.200411/6/2014
Page: 35
Ripple of a diverter switch in a good condition (1100MVA) Ripple
2.5% 2.0%
A UP A DOWN B UP B DOWN C UP C DOWN
1.5% 1.0% 0.5% 0.0% 000
005
010
015
020
025
030
Taps
© OMICRON
04.12.200411/6/2014
Page: 36
Slope of a diverter switch in a good condition (1100MVA) Slope
0.0A/s 000 -0.1A/s
005
010
015
020
025
030 A UP A DOWN B UP B DOWN C UP C DOWN
-0.2A/s -0.3A/s -0.4A/s -0.5A/s -0.6A/s Taps
© OMICRON
04.12.200411/6/2014
Page: 37
Ripple on a Diverter Switch with bouncing Contacts in Phase C Ripple
50.0% 45.0% 40.0% 35.0% 30.0% 25.0% 20.0% 15.0% 10.0% 5.0% 0.0%
A UP A DOWN B UP B DOWN C UP C DOWN
0
2
4
6
8
10
12
Taps
© OMICRON
04.12.200411/6/2014
Page: 38
Slope on a Diverter Switch with bouncing Contacts in Phase C Slope
0.0A/s -0.2A/s 0
2
4
6
8
10
-0.4A/s
12 A UP A DOWN B UP B DOWN C UP C DOWN
-0.6A/s -0.8A/s -1.0A/s -1.2A/s -1.4A/s -1.6A/s -1.8A/s Taps
© OMICRON
04.12.200411/6/2014
Page: 39
Even Interruptions of 500us can be detected
530us
© OMICRON
04.12.200411/6/2014
Page: 40
Ripple = f (Time of Interruption) Dauer der Unterbrechnung [ms] 0.5 1 10 1000
Ripple mit Unterbrechung [%] 4.12 4.64 32.96 100.00
Ripple ohne Unterbrechung [%] 1.00 1.00 1.00 1.00
Slope mit Unterbrechung [mA/s] -42 -49.17 -405.6 -1192
Slope mit Unterbrechung [mA/s] -2 -2 -2 -2
Ripple OS Wicklung mit 0.5A Prüfstrom
120.00 100.00 Ripple [%]
80.00
Ripple mit Unterbrechung
60.00 40.00
Ripple ohne Unterbrechung
20.00 0.00 0.1
1
10
100
1000
Time of Interruption [ms]
© OMICRON
04.12.200411/6/2014
Page: 41
Slope = f (Time of Interruption) Dauer der Unterbrechnung [ms] 0.5 1 10 1000
Ripple mit Unterbrechung [%] 4.12 4.64 32.96 100.00
Ripple ohne Unterbrechung [%] 1.00 1.00 1.00 1.00
Slope mit Unterbrechung [mA/s] -42 -49.17 -405.6 -1192
Slope mit Unterbrechung [mA/s] -2 -2 -2 -2
Slope OS Wicklung mit 0.5A Prüfstrom 0 -200
Slope mit Unterbrechung
Slope [mA/s]
-400 -600
Slope ohne Unterbrechung
-800 -1000 -1200 -1400 0.1
1
10
100
1000
Dauer der Unterbrechung [ms]
© OMICRON
04.12.200411/6/2014
Page: 42
Ripple of an aged diverter switch Ripple
5.5% 5.0%
A UP A DOWN B UP B DOWN C UP C DOWN
4.5% 4.0% 3.5% 3.0% 0
5
10
15
20
Taps
© OMICRON
04.12.200411/6/2014
Page: 43
Slope of an aged diverter switch Slope
-0.6A/s -0.65A/s 0 -0.7A/s -0.75A/s -0.8A/s -0.85A/s -0.9A/s -0.95A/s -1.0A/s -1.05A/s -1.1A/s
5
10
15
20 A UP A DOWN B UP B DOWN C UP C DOWN
Taps
© OMICRON
04.12.200411/6/2014
Page: 44
Aged diverter switch
© OMICRON
04.12.200411/6/2014
Page: 45
Contact Problems (static) Ripple 005 006 007 008 009 009 009 009 010 011 012 013
0.145044615Ω 0.14168819Ω 0.142732395Ω 0.139659045Ω 0.13919992Ω 0.1396798Ω 0.139666415Ω 0.13958899Ω 0.13754698Ω 0.137932135Ω 0.13525902Ω 0.12915814Ω
0.061% 0.046% 0.069% 0.097% 4.612% 1.028% 0.204% 0.174% 0.059% 0.055% 0.086% 0.079%
2.601% 2.253% 2.701% 2.903% 16.975% 14.25% 14.7% 15.7% 15.666% 3.402% 2.703% 3.4%
-1.75A/s -1.65A/s -1.75A/s -1.69A/s -11.37A/s -2.6A/s -1.75A/s -0.56A/s -1.91A/s -1.75A/s -1.69A/s -2.62A/s
20.0A 20.0A 20.0A 20.0A 20.01A 20.0A 20.0A 20.0A 20.0A 20.0A 20.0A 20.0A
2.9008923V 2.8337638V 2.8546479V 2.7931809V 2.7853904V 2.793596V 2.7933283V 2.7917798V 2.7509396V 2.7586427V 2.7051804V 2.5831628V
Ripple
18.0% 16.0% 14.0% 12.0% 10.0% 8.0% 6.0% 4.0% 2.0% 0.0% 000
A UP A DOWN B UP B DOWN C UP C DOWN
005
010
015
020
025
030
Taps
© OMICRON
04.12.200411/6/2014
Page: 46
Contact Problems (static) Slope 005 006 007 008 009 009 009 009 010 011 012 013
0.145044615Ω 0.14168819Ω 0.142732395Ω 0.139659045Ω 0.13919992Ω 0.1396798Ω 0.139666415Ω 0.13958899Ω 0.13754698Ω 0.137932135Ω 0.13525902Ω 0.12915814Ω
0.061% 0.046% 0.069% 0.097% 4.612% 1.028% 0.204% 0.174% 0.059% 0.055% 0.086% 0.079%
2.601% 2.253% 2.701% 2.903% 16.975% 14.25% 14.7% 15.7% 15.666% 3.402% 2.703% 3.4%
-1.75A/s -1.65A/s -1.75A/s -1.69A/s -11.37A/s -2.6A/s -1.75A/s -0.56A/s -1.91A/s -1.75A/s -1.69A/s -2.62A/s
20.0A 20.0A 20.0A 20.0A 20.01A 20.0A 20.0A 20.0A 20.0A 20.0A 20.0A 20.0A
2.9008923V 2.8337638V 2.8546479V 2.7931809V 2.7853904V 2.793596V 2.7933283V 2.7917798V 2.7509396V 2.7586427V 2.7051804V 2.5831628V
Slope
0.0A/s -2.0A/s
A UP A DOWN B UP B DOWN C UP C DOWN
-4.0A/s -6.0A/s -8.0A/s -10.0A/s -12.0A/s 000
005
010
015
020
025
030
Taps
© OMICRON
04.12.200411/6/2014
Page: 47
Measurement of the short circuit impedance a) Measurement of the leakage reactance
© OMICRON
04.12.200411/6/2014
Page: 48
Short circuit impedance Forces
Leakage Flux
10kV Winding 220kVWinding Winding 220kV
220kV
© OMICRON
04.12.200411/6/2014
Page: 49
Short circuit impedance - deviation limits
© OMICRON
04.12.200411/6/2014
Page: 50
400kVA transformer Template: TR Short Circuit Imp. Version: 1.40 3 Phase Measurement Factory Test with W-Meter Uk [V] 1479.40
Ik [A] 8.89
P [W] 6270
f [Hz] 50
Z [OHM] Phi [°] R [OHM] X [OHM] L [H] 288.2335 74.02338 79.33485 277.1002 0.882037449
f [Hz] 50
Z [OHM] Phi [°] R [OHM] X [OHM] L [H] 287.8106 74.21368 78.29901 276.9553 0.881576072 -0.14671 0.257084 -1.30566 -0.05231 -0.05230818
f [Hz] 50
Z [OHM] Phi [°] R [OHM] X [OHM] L [H] 287.9643 73.82169 80.23478 276.5607 0.880319891 -0.09342 -0.27247 1.134345 -0.19473 -0.19472629
f [Hz] 50
Z [OHM] Phi [°] R [OHM] X [OHM] L [H] 288.7539 74.01075 79.53928 277.583 0.883574133 0.180545 -0.01706 0.257675 0.17422 0.174219805
Phase A
Difference to Factory Test [%] Phase B
Difference to Factory Test [%] Phase C
Difference to Factory Test [%] Average Difference to Factory Test [%]
-0.01986
-0.01082 0.028788
-0.02427 -0.02427155 © OMICRON
04.12.200411/6/2014
Page: 51
Measurement of the short circuit impedance b) Measurement of the AC-short circuit resistance (FRSL = Frequency response of stray losses)
© OMICRON
04.12.200411/6/2014
Page: 52
Parallel strands without twisting B
HV Winding
Losses by induced currents
LV Winding
© OMICRON
04.12.200411/6/2014
Page: 53
Parallel strands with twisting B
HV Winding
Induced currents are compensated
LV Winding
© OMICRON
04.12.200411/6/2014
Page: 54
Parallel strands with short circuit B
HV Winding
Additional losses by induced currents
LV Winding
© OMICRON
04.12.200411/6/2014
Page: 55
Equivalent circuit diagram
© OMICRON
04.12.200411/6/2014
Page: 56
R (f)
© OMICRON
04.12.200411/6/2014
Page: 57
Comparison of the 3 phases R(f) 4.5 Ohm 4.0 Ohm 3.5 Ohm 3.0 Ohm 2.5 Ohm 2.0 Ohm 1.5 Ohm 1.0 Ohm 0.5 Ohm 0.0 Ohm
A B C
0
100
200
300
400
500
Frequency (Hz)
© OMICRON
04.12.200411/6/2014
Page: 58
Case study
40-MVA, Y∆ ∆, 121 kV/12.85 kV transformer The transformer was removed from service because it produced gas, which, upon analysis, showed a hot spot involving paper. In the laboratories, however, none of the standard tests showed a fault in the windings. In fact, it was found that: • The turns ratio was correct; • The excitation current was normal; • The DC resistance was normal; • A comparative measurement of the impedance in the three phases showed no significant difference (less than 3%).
© OMICRON
04.12.200411/6/2014
Page: 59
Case study
40-MVA, Y∆ ∆, 121 kV/12.85 kV transformer
© OMICRON
04.12.200411/6/2014
Page: 60
Case study
40-MVA, Y∆ ∆, 121 kV/12.85 kV transformer
Phase A: eight of the 13 parallel strands of this winding had been shortcircuited. In this condition, the section perpendicular to the lines of flux was much higher and, hence, the eddy current losses Phase B: two parallel strands were found to be in short-circuit but the fault was not located in the winding after it had been dismantled Phase C: No fault was detected in the windings
© OMICRON
04.12.200411/6/2014
Page: 61
Local Overheating
© OMICRON
04.12.200411/6/2014
Page: 62
Short circuit impedance - deviation limits
© OMICRON
04.12.200411/6/2014
Page: 63
Diagnosis of a damaged transformer 220kV / 110kV / 10kV • Short
circuit of the 10kV winding by a marten •Short circuit current Is = 52 kA •Switching “off” time about 100ms
Result: Short circuit of the 10kV winding to the core (Phase A)
© OMICRON
04.12.200411/6/2014
Page: 64
Ratio and excitation current
Ratio Error = -21.5% !
© OMICRON
04.12.200411/6/2014
Page: 65
Lk=f(f) Faulty winding
© OMICRON
04.12.200411/6/2014
Page: 66
Defective 10kV winding skineffect in the core Low Frequencies
High Frequencies
© OMICRON
04.12.200411/6/2014
Page: 67
Rk=f(f) Rk 110kV - 10kV 30.00 25.00
Ohms
20.00 Rk [Ohm] U Rk [Ohm] W Rk [Ohm] V
15.00 10.00 5.00 0.00 0
100
200
300
400
f [Hz]
© OMICRON
04.12.200411/6/2014
Page: 68
FRA phases V und W
Phase: V
Phase: W
© OMICRON
04.12.200411/6/2014
Page: 69
FRA Phases U und W
Phase: U
Phase: W
© OMICRON
04.12.200411/6/2014
Page: 70
Opened Transformer
Defective Phase
Current limiting coils © OMICRON
04.12.200411/6/2014
Page: 71
View from the Top 220 kV 110 kV
10 kV
© OMICRON
04.12.200411/6/2014
Page: 72
View from the Top
© OMICRON
04.12.200411/6/2014
Page: 73
View from the Top
Broken wire
© OMICRON
04.12.200411/6/2014
Page: 74
CAPACITANCE AND TAN DELTA MEASUREMENTS ON TRANSFORMERS
© OMICRON
04.12.200411/6/2014
Page: 75
Definition of Tan Delta Equivalent Parallel Circuit Diagram and Vector Diagram
Mainly conductive losses
with and
Frequency
© OMICRON
04.12.200411/6/2014
Page: 76
Equivalent Serial Circuit Diagram Mainly polarization losses
RSS
URs
tan δ = CS
UR = RSω C S UC
UCs
© OMICRON
04.12.200411/6/2014
Page: 77
Frequency Curves for Serial and Parallel Circuit Diagram 8.00E-03 7.00E-03 6.00E-03 5.00E-03
Serial
4.00E-03
Parallel
3.00E-03
Sum
2.00E-03 1.00E-03 0.00E+00 0
100
200
300
400
500
© OMICRON
04.12.200411/6/2014
Page: 78
Transformer Winding Insulation b. Model for the behaviour of a dielectric with polarisation characteristic and conductivity
a. Plate condenser as a model for dielectric insulation
c. Part of the cross section of a power transformer main insulation system between HV and LV windings
d. Simplified geometry model for the main components oil, barriers and spacers
e: Dielectric model for the insulation system of power transformers
© OMICRON
04.12.200411/6/2014
Page: 79
Tan Delta (f) Pressboard Dependent on the Water Content
© OMICRON
04.12.200411/6/2014
Page: 80
Losses in Dielectric Material •Transport of electrons and ions •Losses through polarisation effects
•Losses in dielectrics are dependent of •Ageing •Water content •Conductive losses by particles •Partial discharges © OMICRON
04.12.200411/6/2014
Page: 81
What can C-Tan Delta tell us? •Capacity:
• Bushings: • Partial breakdowns between layers • Incoming oil into cracks of solid insulation (RBP hard paper)
• Transformer windings: • Change of the geometry between windings (deformation and displacement of windings due to big fault currents trough the transformer)
© OMICRON
04.12.200411/6/2014
Page: 82
What can C-Tan Delta tell us? •Dissipation factor:
• Bushings: • Aging and decomposition of insulation • Water content • Bad contacted electrodes or capacitive layers • Cracks in the insulation • Partial discharges
• Transformers: • Aging • Water content in the oil and in the paper • Contamination by particles © OMICRON
04.12.200411/6/2014
Page: 83
Schering Bridge (1919) First application for insulation diagnosis 1924
Has to be balanced for each frequency
© OMICRON
04.12.200411/6/2014
Page: 84
Measuring Principle of CP TD1
Im
CN
ZN
ZX CX, LX
Icn
Icx
ICX
ICN
δ=
u0(t)
δ
UN(t)
Z1
with δ << 1 : δ ≅ tanδ ≅ cosϕ
Z2
π 2
−ϕ
δ , ϕ L in rad
UX(t) ϕ
Uo Re
Reference path
Measurement path
Good solution for the automatic measurement at different frequencies © OMICRON
04.12.200411/6/2014
Page: 85
Universal Transformer Test and Diagnosis System Power amplifier 15-400Hz •Outputs up to 2000A, 2kV AC / 400A DC •Measurement of •Ratio •Complex Impedance •Resistance • …...
C-Tanδ δ-Test System
© OMICRON
04.12.200411/6/2014
Page: 86
Features and Advantages of the Described Test system • One test system for complete transformer testing • Excellent noise suppression (50/60 Hz) • Variable frequency of output voltage 15…400Hz enables frequency sweeps • Most accurate instrument for field use (TD: 5*E-5 C: 0.05%) • Automatic test procedures with voltage and frequency sweeps -> saves testing time ! • Automatic reporting and easy export to Excel --> saves time for post-processing !
© OMICRON
04.12.200411/6/2014
Page: 87
Block Diagram of CP TD1 Tanδ - measurement with CP DF12 Monday, 01. July 2002 High voltage output (0..12kV)
CN select channel
EUT (Cx)
primary
Ix_in In A
B_1
sec.
ADC
B_PE
tertiary
In B guard safety voltage-booster
calib RS232 & supply
CPC100 mains
DSP
serial-Interface
booster-Interface
B_2
CP TD1
Relay matrix for 7 different measuring modes without rewiring:
UST-A, UST-B, UST A+B FUNCTIONAL EARTH
GST, GSTgA, GSTgB, GSTgA+B
© OMICRON
04.12.200411/6/2014
Page: 88
Screenshot UST-B Mode
© OMICRON
04.12.200411/6/2014
Page: 89
C-Tan-Delta Measurement on Power Transformers Low Voltage Bushing 400kV Bushing Measuring Tap
Core
Tapped Winding High Voltage Winding Low Voltage Winding © OMICRON
04.12.200411/6/2014
Page: 90
No se puede mostrar la imagen en este momento.
Transformer Winding Test
© OMICRON
04.12.200411/6/2014
Page: 91
Test Procedure for a 3-Windings Transformer No se puede mostrar la imagen en este momento.
© OMICRON
04.12.200411/6/2014
Page: 92
Tan Delta (f) with treated (dry) oil DF (f) H, HL, L 0.45 % 0.4 % 0.35 % 0.3 %
H(f) HL(f) L(f)
0.25 % 0.2 % 0.15 % 0.1 % 0.05 %
© OMICRON
450.0 Hz
400.0 Hz
350.0 Hz
300.0 Hz
250.0 Hz
200.0 Hz
150.0 Hz
100.0 Hz
50.0 Hz
0.0 Hz
0.0 %
04.12.200411/6/2014
Page: 93
Tan Delta (f) with aged oil DF (f) H, HL, L 0.6 %
0.5 %
0.4 %
H(f) HL(f) L(f)
0.3 %
0.2 %
0.1 %
© OMICRON
450.0 Hz
400.0 Hz
350.0 Hz
300.0 Hz
250.0 Hz
200.0 Hz
150.0 Hz
100.0 Hz
50.0 Hz
0.0 Hz
0.0 %
04.12.200411/6/2014
Page: 94
Tan Delta (f) of a 110kV transformer with high water content DF (f) H, HL 1.8 % 1.6 % 1.4 % 1.2 %
H(f) HL(f)
1.0 % 0.8 % 0.6 % 0.4 % 0.2 %
© OMICRON
450.0 Hz
400.0 Hz
350.0 Hz
300.0 Hz
250.0 Hz
200.0 Hz
150.0 Hz
100.0 Hz
50.0 Hz
0.0 Hz
0.0 %
04.12.200411/6/2014
Page: 95
Tan Delta 11kV-0.4kV 800KVA (1966) DF HV-LV (f) 2.5 % 2.0 % 1.5 % 1.0 % 0.5 % 0.0 % 0.0 Hz
50.0 Hz
100.0 Hz
150.0 Hz
200.0 Hz
© OMICRON
250.0 Hz
04.12.200411/6/2014
Page: 96
Unexpected ferquency curves 8.0 % 220kV Gießharzdurchführungen
7.0 % 6.0 %
0.8 % 0.75 %
5.0 %
0.7 %
4.0 %
0.65 %
3.0 %
0.6 % 0.55 %
2.0 %
0.5 %
1.0 %
Phase A Phase B Phase C
0.45 % 0.4 %
100.0 Hz 200.0 Hz 300.0 Hz 400.0 Hz 500.0 Hz
0.0Hz 50.0Hz 100.0H 150.0H 200.0H 250.0H 300.0H 350.0H 400.0H 450.0H z z z z z z z z
DF (f) 1.0 %
0.5 %
450.0 Hz
400.0 Hz
350.0 Hz
300.0 Hz
250.0 Hz
200.0 Hz
150.0 Hz
100.0 Hz
-0.5 %
50.0 Hz
0.0 % 0.0 Hz
0.0 % 0.0 Hz -1.0 %
17.0 Hz 30.0 Hz 80.0 Hz 130.0 Hz 230.0 Hz 400.0 Hz
-1.0 %
-1.5 %
© OMICRON
04.12.200411/6/2014
Page: 97
Phases Not Connected or Bad Contacts
Currents through the windings cause additional inductive losses
© OMICRON
04.12.200411/6/2014
Page: 98
Phases Connected
All phases of the windings are on the same potential
© OMICRON
04.12.200411/6/2014
Page: 99
DF (f) 0.7 % 0.5 % 0.3 %
450.0 Hz
400.0 Hz
350.0 Hz
300.0 Hz
250.0 Hz
200.0 Hz
150.0 Hz
100.0 Hz
-0.3 %
50.0 Hz
Bad contact of short circuit
-0.1 %
0.0 Hz
0.1 %
-0.5 % -0.7 % -0.9 % -1.1 % -1.3 % -1.5 %
DF (f) 0.8 % 0.7 % 0.6 %
0.4 % 0.3 % 0.2 % 0.1 %
© OMICRON
04.12.200411/6/2014
450.0 Hz
400.0 Hz
350.0 Hz
300.0 Hz
250.0 Hz
200.0 Hz
150.0 Hz
100.0 Hz
50.0 Hz
0.0 % 0.0 Hz
Good contacts of short circuit
0.5 %
Page: 100
No se puede mostrar la imagen en este momento.
HV Bushings
© OMICRON
04.12.200411/6/2014
Page: 101
Capacitive Bushings (1) Emax= high
A
Emax= smaller A
without capacitive layers
with capacitive layers Earthing Cap
© OMICRON
04.12.200411/6/2014
Page: 102
Capacitive Bushings (2)
© OMICRON
04.12.200411/6/2014
Page: 103
Bushing Measuring Tap
© OMICRON
04.12.200411/6/2014
Page: 104
C-Tan Delta Progression of a Bushing C Tan-Delta Progression of a 220 kV RBP (Hard Paper) Bushing Year of Manufacturimg 1961, horizontal mounted, oil filled Tan Delta
Change of Capacitance
30
20
-3
Tan Delta x 10 Change of Capacitance %
25
15
10
5
0 75
77
79
81
83
85
87
89
-5
Source: RWE
Date of Measurement
© OMICRON
04.12.200411/6/2014
Page: 105
Bushing Fault
© OMICRON
04.12.200411/6/2014
Page: 106
Bushing after Explosion
© OMICRON
04.12.200411/6/2014
Page: 107
DF 145kV RIP (MICAFIL new)
© OMICRON
04.12.200411/6/2014
Page: 108
220kV RIP Bushing stored outside
© OMICRON
04.12.200411/6/2014
Page: 109
220kV RIP Bushing stored outside 0.85 % 0.75 %
Minimum
Tan Delta
0.65 %
31.03.2004 15.07.2004 08.10.2004
0.55 % 0.45 %
Minimum
0.35 %
Minimum 0.25 % 0.0 Hz
100.0 Hz
200.0 Hz
300.0 Hz
400.0 Hz
© OMICRON
500.0 Hz
04.12.200411/6/2014
Page: 110
66kV Oil Circuit Breaker (USA)
© OMICRON
04.12.200411/6/2014
Page: 111
DF (f) 69 kV OIP Bushings Circuit Breaker Bushing C-PF Test V TEST* [V] 10032.20 10031.81 10031.55 10031.20 10028.73 10030.49
C meas. PF meas.[%] 2.836E-10 0.457 2.815E-10 0.491 2.853E-10 0.493 2.837E-10 0.486 2.855E-10 0.504 2.853E-10 0.449
© OMICRON
04.12.200411/6/2014
Page: 112
DF (f) 69 kV OIP Bushings 60Hz 0.6 % 0.5 % 1 2 3 4 5 6
0.4 % 0.3 % 0.2 % 0.1 % 0.0 % *0.0 Hz
*100.0 Hz *200.0 Hz *300.0 Hz *400.0 Hz *500.0 Hz
© OMICRON
04.12.200411/6/2014
Page: 113
DF (f) 69 kV OIP Bushings 17-400Hz
© OMICRON
04.12.200411/6/2014
Page: 114
OIP bushings 420kV (1994) Tan Delta
C
0.5
415
0.45
410
0.4
405 400
0.35
0.25
U
395
V
390
W
0.2
pF
%
0.3
U
+ 10%
V
385
W
380
0.15
375
0.1
370
0.05
365
0
360
0
100
200 Hz
300
400
0
100
200
300
400
Hz
© OMICRON
04.12.200411/6/2014
Page: 115
Defectice 110 kV RPB Bushing C
Tan Delta 340
1.5
335
1.3
330 1.1
325
2V 2W
0.9
2N 1N
0.7
pF
%
2U
2U
2V 2W
320
2N
315
1N
310 0.5
305 300
0.3 0
100
200
300
Hz
Tan Delta (f)
400
0
100
200
300
400
Hz
C (f)
© OMICRON
04.12.200411/6/2014
Page: 116
Defectice 110 kV RPB Bushing Tan Delta (U) 0.75 0.7 0.65 0.6 2V
%
0.55
2N 0.5 0.45 0.4 0.35 0.3 0
5
10
15
kV
Tan Delta (V) © OMICRON
04.12.200411/6/2014
Page: 117
Suspicious 400 kV OIP Bushings (1998) Tan Delta (U) 0.5% 0.45% 0.4% 0.35% 0.3%
Spannungsverläufe unauffällig U TanDelta V TanDelta
0.25%
W TanDelta
0.2% 0.15% 0.1% 0.05% 0.0% 0.0V
2000.0V
4000.0V
6000.0V
8000.0V 10000.0V 12000.0V 14000.0V
© OMICRON
04.12.200411/6/2014
Page: 118
Suspicious 400 kV OIP Bushings (1998) Reason ? Tan Delta (V)
0.49%
0.47%
Frequenzververläufe auffällig
0.45% U TanDelta V TanDelta
0.43%
W TanDelta
0.41%
0.39%
0.37% 0.0 Hz
50.0 Hz
100.0 Hz
150.0 Hz
200.0 Hz
250.0 Hz
300.0 Hz
350.0 Hz
© OMICRON
04.12.200411/6/2014
Page: 119
Suspicious 123 kV RIP Bushing Reason ? 0.8% 0.7% Tan Delta
0.6% 0.5%
73
0.4%
80
0.3% 0.2% 0.1% 0.0% 0.0 Hz
100.0 Hz 200.0 Hz 300.0 Hz 400.0 Hz 500.0 Hz
© OMICRON
04.12.200411/6/2014
Page: 120
Measurement with high interference
Durchführung
HS Anschluss
Erdungsgarnitur
© OMICRON
04.12.200411/6/2014
Page: 121
Measurement with high interference
© OMICRON
04.12.200411/6/2014
Page: 122
Thank you for your Attention !
© OMICRON
04.12.200411/6/2014
Page: 123
