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PROGRESS REPORT No 1T-B
Results of the autotransformer AODCTN-167000/500/220 No.64458 (1T phase B)
testing
Head of diagnostic department_______________ .. Popov
_____ ______________2007
Diagnostician_______________V.V. Makolkin_____ ______________2007
2007
SCIENTIFIC AND ENGINEERING NTERZTZ-Service Co.
11, Dnepropetrovskoye sh., Zaporozhye, 69069, Ukrainetel.: (380 61) 280-2801, fax: (380 61) 280-2800
E-mail: root@ztz-service.com.uahttp://www.ztz-service.com.ua
SEC ZTZ-SERVICE Co.
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1. Main technical data of the autotransformer No.64458 (1T phase B)Type DCN-167000/500/220
No., manuf. date 64458 (1T ph. B), 1967
Calculation sheet 215 740Capacity HV / MV / LV, kVA 167000 / 167000 / 50000
Voltage HV / MV / LV, kV 500 / 230 6 2.06 / 11.0
Current HV / MV / LV, A 578 / 1256 / 4545
Connection diagram 1auto/1-0-0
Frequency, Hz 50
OLTC SAV-220/1600-3/12/1
Cooling system OFAF (6 coolers + 1 spare)
Weight of oil, t 44
Table 1.1 No-load losses and currents
Energized U, V I, P, W"b - y" 380 0.90 188.0
No-load losses 0 = 123 kW No-load current I0 = 0.34 %
Table 1.2. Windings resistance at t= 21C
WindingOLTC
positionR, Ohms
B - 0 - 0.400
Bm-0
1 0.174
2 0.168
3 0.1624 0.158
5 0.150
6 0.146
7 0.138
8 0.134
9 0.128
10 0.122
11 0.116
12 0.110
13 0.106
b y - 0.00122
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Progress report No. 1T-B Sheet 2Sheets 16
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Table 1.3. Short circuit losses and impedances (Zk) at 75C.Windings
pair*Voltage
Full losses
Related tocapacity
Uk (Related to167 MVA)
Calculatedimpedance
(Zk)MW MV % Ohms
HV MV7 500/3/230/3 329 167 9.40 46.949
HV-LV 500/3/11.0 98.1 50 30.0 149.836
MV7 - LV 230/3/11.0 84.9 50 18.0 19.031
* Note: MV7 middle voltage winding at 7 tap position (230 kV).
Table 1.4. Insulation characteristics R15/R60 & tan
Scheme
t= 37C t= 56CU
R15 R60 tan R15 R60 tanMOhm MOhm % MOhm MOhm % kV
HV-(LV+G) 470 850 0.3 260 400 0.5 10
LV-(HV+G) 350 900 0.3 220 420 0.6 10
(HV+LV)-G 240 500 0.3 150 240 0.6 10
Image 1. General view of autotransformer
SEC ZTZ-Service Co.
Progress report No. 1T-B Sheet 3
500 kVbushing OLTC
bushing
220 kVbushing
OLTC
Maincore leg(HV)
Tappingcore leg
Freecore leg
11 kVbushings
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2.3 Results of leakage reactance measurement (impedances).
Leakage reactance (Zk) measurements were carried out for HV-MV, HV-LV and MV-
LV windings pairs at the maximum (1 tap), rated (7 tap) and minimum (13 tap) taps of theMV winding.
Table 2.3
Windings pair Zk calc., Ohm Zk meas., OhmZk, %
(Zk meas/ Zk calc)
HV MV1 - 53.75 -
HV MV 7 46.95 46.25 - 1.49
HV MV13 - 52.50 -
HV LV 149.84 149.9 0.04
MV1 LV - 24.98 -
MV7 LV 19.03 19.63 3.15MV13 LV - 18.19 -
Conclusion: Low difference between calculated impedances and measured duringcondition assessment testifies the absence of the windings displacement (deformation).Deviation of the measured values from calculated not exceed 5%.
2.4 Insulation electrical characteristics
Table 2.4.
No Scheme
04.03.2007
tw.=+60, tair=25
06.03.2007
tw.=+33, tair=18
tan,%
C,pF
R15,MOhm
R60,MOhm
tan,%
C,pF
R15,MOhm
R60,MOhm
1 HV (LV+G) 0.90 9991 85.4 89.5 0.33 10031 405 562
2 LV - (HV +G) 1.18 18886 51.00 55.00 0.38 18864 266.1 487
3 (HV +LV) G 1.08 23473 39.94 43.00 0.37 23487 218.5 345.2
4 HV LV 1.10 2697.4 295 311.5 0.33 2700.6 1147 1953
5 HV G 0.82 7293 124.2 129.1 0.32 7329 616 803
6 LV HV 1.10 2698 - - 0.33 2700.3 - -
7 LV - G 1.2 16186 62.3 67.9 0.38 16162 336.7 660
Remark: tw windings temperature calculated from measured DC current resistance of HV-winding.
Table 2.5 Comparison of the measured values and certified
No Scheme
R60, MOhm
Certified at
t=56C
Measured at
t=60C
Reduced to
t=56C1 HV (LV+G) 400 89.5 105.32 LV - (HV +G) 420 55.00 64.73 (HV +LV) G 240 43.00 50.6
Conclusion: Main insulation of the autotransformer is in bad condition. Insulationcontamination by polar aging products presumed.
During repair insulation shall be washed with special oil by oil-spray method.
SEC ZTZ-Service Co.
Progress report No. 1T-B Sheet 5
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2.5 Insulation electrical characteristics of the bushings
Table 2.6
No Scheme
04.03.2007
tw.=+60, tair=25, tbush=43
06.03.2007
tw.=+ 33, tair=18 , tbush=26tan,
%
C,pF
R15,MOhm
R60,MOhm
tan,%
C,pF
R15,MOhm
R60,MOhm
500 kV bushing
1 1 0.20 619.3 11170 16020 0.31 615.6 31570 58600
2 1inv. 0.18 618.7 - - 0.31 616.3 - -
3 3 0.39 3055.2 10710 15590 0.26 3071.5 42500 69100
4 1+3 0.36 3674.6 - - 0.26 3688.0 - -
220 kV bushing
5 1 0.23 570.7 10640 15180 0.35 567.2 29090 45500
6 1inv. 0.21 565.1 - - 0.30 556.5 - -
7 3 0.88 880.4 9050 15110 0.53 867.5 28380 45400
8 1+3 0.62 1445.5 - - 0.44 1424.1 - -
220 kV OLTC bushing
9 1 0.26 430.2 1891 5700 0.35 427.9 2855 10090
10 1inv. 0.24 426.9 - - 0.31 419.8 - -
11 3 1.60 1036.8 1909 5560 0.76 954.9 2387 9840
12 1+3 1.20 1463.7 - - 0.61 1374.7 - -Remark: tw windings temperature calculated from measured DC current resistance of HV-winding.
tbush bushings temperature, calculated from tw & tair.
Conclusion: Results of the insulation characteristics measurements testifies that allbushings are in normal condition.
SEC ZTZ-Service Co.
Progress report No. 1T-B Sheet 6
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3. OLTC checking.OLTC type SAV-220/1600-3/12/1
3.1 OLTC oscillograms
Image 2. OLTC switching from 7 tap position to 8 tap position
Image 3. OLTC switching from 8 tap position to 7 tap position
Table 3.1Tapping Certified time (seconds) Measured time (seconds)
From odd toeven (from 7 to8)
t1 0.010 - 0.030 0.020
t2 0.020 - 0.042 0.030
t3 0.010 - 0.020 0.019
ttotal 0.048 0.085 0.069
From even toodd (from 8 to 7)
t1 0.010 - 0.030 0.021
t2 0.020 - 0.042 0.024
t3 0.010 - 0.020 0.028
ttotal 0.048 0.085 0.073
SEC ZTZ-Service Co.
Progress report No. 1T-B Sheet 7
t1 t2 t3
t, seconds
I, amperes
t1 t2 t3
t, seconds
I, amperes
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3.2 Diverter switch circle diagram (degrees)
No OLTC tapping Certified Testing result
1 From 7 tap position to 8 tap position
1560-1800
1730
2 From 8 tap position to 9 tap position 1700
3 From 9 tap position to 8 tap position 1600
4 From 8 tap position to 7 tap position 1620
Conclusion: OLTC is in normal condition.
4. Results of partial discharges (PD) location by acoustic method
Date: 25.02.2007
Conditions:- oil temperature 52;- load 44%.
PD location was done at 3 levels around the autotransformer tank (see Image 5):- 1 level 500 millimeters above the tank joint- 2 level 1600 millimeters above the tank joint (middle of the tank height)- 3 level - 2800 millimeters above the tank joint
Before the measurements performance the basic level of acoustic signal was
measured.At all points around the tank (at all levels) the measured signals not exceed the basiclevel of acoustic signal and amount 0 1.94 dB (allowed level of acoustic signal is 20 dB).
Conclusion:Partial discharges activity inside the tank not presumed.
5. Results of the oil pumps & fans vibrations and currents measurements
Date: 27.02.2007The points of the oil pumps vibration measurements are shown on the image 4.Vibrations of the oil pumps were assessed on the ISO 2372 recommendations and
ZTZ-Service Co experience basis:
- vibration velocity 2.8 millimeters per second normal condition;
- vibration velocity > 2.8 millimeters per second bad condition
SEC ZTZ-Service Co.
Progress report No. 1T-B Sheet 8
Z1 1
1
2
2 Z1 1,2
1,2
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vertical axis; horizontal axis; Z rotation axis.
Image 4. Points of the oil pumps vibration measurements.
Table 5.1. Oil pumps vibrations, millimeter per second
Cooler (pump) No. X1 Y1 X2 Y2 Z Condition1 1.2 0.8 1.3 0.7 0.5 Normal
2 0.9 1.0 0.9 1.1 0.3 Normal
3 1.2 1.1 1.1 1.1 1.0 Normal
4 0.6 0.6 0.6 0.6 0.5 Normal
5 0.9 1.0 0.6 0.7 0.4 Normal
6 1.5 1.3 1.3 1.1 1.3 Normal
7 2.5 4.3 1.2 2.0 2.9 Bad
Table 5.2. Oil pumps currents, Amperes.
Cooler (pump) No. Phase * Phase * Phase * Max. difference betweenphases, %
1 5.58 5.27 5.46 5.88
2 5.65 5.61 5.52 2.36
3 5.86 5.87 5.85 0.34
4 6.08 5.98 6.03 1.67
5 5.32 5.36 5.20 3.08
6 6.75 6.75 6.60 2.27
7 5.76 5.87 5.75 2.09* Note: phases marking - from left to right
Conclusion: Oil pump No. 7 shall be repaired. All other oil pumps are in normalcondition. Pressure-gauge at the oil pump No. 6 shall be replaced.
The points of the fans vibration measurements are the follow:- X1 horizontal axis of a lower fan;- Y1 - vertical axis of a lower fan;- X2 horizontal axis of an upper fan;- Y2 - vertical axis of an upper fan.Vibrations of the fans were assessed on the ISO 2372 recommendations and ZTZ-
Service Co experience basis:
- vibration velocity 4.5 millimeters per second normal condition;
- vibration velocity > 4.5 millimeters per second bad condition
SEC ZTZ-Service Co.
Progress report No. 1T-B Sheet 9
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Table 5.3. Fans vibrations, millimeter per second
Cooler No.Lower fan Upper fan
ConditionX1 Y1 X2 Y2
1 1.0 1.3 1.0 1.3 Normal2 1.5 1.4 1.0 1.2 Normal
3 1.7 1.1 1.2 1.6 Normal
4 1.2 1.2 1.3 1.6 Normal
5 1.0 1.0 1.4 1.0 Normal
6 2.6 1.6 2.5 2.0 Normal
7 2.3 2.3 4.7 1.6 Bad shall be repaired
Table 5.4. Fans currents, Amperes.Cooler
No.Fan No. Phase * Phase * Phase *
Max. difference between
phases, %
11 (lower) 5.68 5.55 5.73 3.24
2 (upper) 6.25 6.25 6.41 2.56
21 (lower) 5.78 5.65 5.86 3.72
2 (upper) 5.49 5.50 5.51 0.36
31 (upper) 5.27 5.18 5.16 2.13
2 (lower) 5.45 5.38 5.42 1.30
41 (upper) 6.02 5.80 5.97 3.79
2 (lower) 5.69 5.47 5.80 6.03
51 (lower) 5.60 5.64 5.46 3.30
2 (upper) 5.08 5.20 5.00 4.00
6 1 (lower) 5.65 5.68 5.56 2.162 (upper) 5.25 5.26 5.20 1.15
71 (upper) 5.85 5.92 5.75 2.96
2 (lower) 4.97 5.05 4.78 5.65* Note: phases marking - from left to right
Conclusion: At the cooler No. 7 bearings of the upper fans shall be replaced.All other fans are in normal condition.
6. Results of the magnetic field intensity measurements
Measurements of the magnetic field intensity (MFI) were done around theautotransformer tank at load 44% and at no-load.
Date: 25.02.2007
Conditions: oil temperature 52; load 44%.Date: 02.03.2007
Conditions: oil temperature 63; no-load.
Points of the MFI measurements are shown at the image 5.
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Progress report No. 1T-B Sheet 10
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- points for partial discharges location- points for measurement of magnetic flux intensity
Image 5. Points of the PD location and MFI measurements.
0
1
2
3
4
5
6
7
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73
Point No.
Relative units
Load 44%
No-load
Image 6. MFI distribution around the tank joint at 44% load and no-load.
SEC ZTZ-Service Co.
Progress report No. 1T-B Sheet 11
500 kVbushing
220 kVbushing
OLTC
11 kVbushings
1
2
3
4
56
7812 11
109
16
15
1413
17
18
19
2021
22 23
24 25
2627
28 29
30
31
32
1
1020
30
40
50
56
63
60
70
1
1
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Table 6.1. Results of the MFI measurements at 44% load and no-load.
PointNo
Magnetic field intensity,relative units
PointNo
Magnetic field intensity,relative units
PointNo
Magnetic field intensity,relative units
Load 44% No-load Load 44% No-load Load 44% No-load
1 0.80 0.02 26 1.34 0.20 51 3.22 0.24
2 0.47 0.01 27 4.10 0.46 52 3.43 0.39
3 0.45 0.01 28 5.12 0.84 53 6.45 0.91
4 0.51 0.01 29 1.26 0.85 54 3.16 0.16
5 0.72 0.02 30 4.01 0.27 55 3.65 0.54
6 0.99 0.04 31 4.32 1.33 56 4.27 0.73
7 1.06 0.05 32 2.26 0.28 57 0.50 0.12
8 0.86 0.05 33 1.72 0.12 58 0.28 0.08
9 0.25 0.05 34 1.33 0.32 59 1.07 0.04
10 0.34 0.03 35 1.46 0.15 60 0.54 0.02
11 0.90 0.06 36 0.74 0.17 61 1.86 0.14
12 1.10 0.07 37 0.66 0.09 62 3.94 0.3013 0.92 0.15 38 0.70 0.08 63 0.60 0.07
14 0.78 0.16 39 3.47 0.03 64 0.74 0.05
15 0.84 0.01 40 2.90 0.13 65 2.70 0.12
16 0.42 0.09 41 5.27 0.18 66 2.16 0.09
17 0.14 0.12 42 4.63 0.30 67 1.65 0.03
18 0.63 0.19 43 2.02 0.02 68 1.96 0.03
19 0.47 0.17 44 1.87 0.01 69 0.65 0.03
20 4.08 0.63 45 0.66 0.06 70 0.59 0.02
21 4.38 0.90 46 0.93 0.11 71 0.38 0.01
22 2.59 0.25 47 2.15 0.16 72 1.11 0.02
23 4.60 0.53 48 2.53 0.18 73 0.73 0.02
24 4.30 0.50 49 1.72 0.19 74 0.15 0.0225 1.43 0.12 50 0.80 0.17
Conclusion: Any deviation from normal condition not exposed. Peaks at some pointsare related to autotransformer design (magnetic shunts and leads arrangement).
7. Results of the autotransformer vibration measurements
Date: 27.02.2007
Conditions: oil temperature 60; load 37%.Date: 02.03.2007
Conditions: oil temperature 63; no-load.
Vibration measurements were done at 3 levels around the autotransformer tank (seeImage 7):
- 1 level 500 millimeters above the tank joint- 2 level 1600 millimeters above the tank joint (middle of the tank height)- 3 level - 2800 millimeters above the tank joint
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Progress report No. 1T-B Sheet 12
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- points for the vibration assessment by the special software Vesta- points for the analytical estimation
Image 7. Points for the vibration measurements.
Table 7.1. Vibro-acceleration at 37% load and no-load (m/s2).PointNo
Level 1 PointNo
Level 2 PointNo
Level 3
Load 37% No-load Load 37% No-load Load 37% No-load
1 2.256 1.816 1 1.198 1.266 1 1.000 1.235
2 1.521 2.358 2 1.620 1.570 2 1.000 1.718
3 1.116 1.517 3 2.640 2.760 3 2.701 2.054
4 2.608 3.497 4 1.250 2.221 4 1.000 1.367
5 3.073 3.020 5 2.300 3.507 5 3.551 4.245
6 1.335 1.391 6 2.788 3.307 6 3.417 4.700
7 2.11 2.938 7 1.917 2.988 7 1.180 1.158
8 1.874 3.150 8 1.594 2.836 8 1.571 2.234
9 1.454 1.636 9 1.355 2.283 9 1.881 2.693
10 1.000 1.166 10 1.000 1.000 10 1.000 1.000
All measured values not exceed allowed vibro-acceleration value (9.81 m/s2).
SEC ZTZ-Service Co.
Progress report No. 1T-B Sheet 13
500 kVbushing
220 kVbushing
OLTC
Maincore leg(HV)
Tappingcore leg
Freecore leg
1
2
3
5
4
7
6
10
98
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Table 7.2. Vibro-velocity at 37% load and no-load (millimeter per second).PointNo
Level 1 PointNo
Level 2 PointNo
Level 3
Load 37% No-load Load 37% No-load Load 37% No-load
1 3.753 2.837 1 1.845 1.980 1 1.519 1.6942 2.474 3.513 2 2.611 1.236 2 1.135 1.466
3 1.814 2.477 3 2.194 2.960 3 2.245 2.525
4 4.349 4.690 4 1.157 2.266 4 1.005 2.224
5 5.108 4.935 5 1.520 3.066 5 2.928 4.547
6 1.562 2.145 6 2.033 5.484 6 2.875 4.760
7 2.062 3.183 7 2.141 3.241 7 1.359 1.518
8 3.084 4.193 8 2.619 2.804 8 2.445 2.990
9 2.355 1.415 9 1.166 1.917 9 2.548 2.707
10 1.373 1.239 10 1.015 1.000 10 1.581 1.476
Table 7.3. Vibro-displacement at 37% load and no-load (micrometer).
PointNo
Level 1 PointNo
Level 2 PointNo
Level 3Load 37% No-load Load 37% No-load Load 37% No-load
1 16.81 12.69 1 13.31 13.93 1 15.81 13.21
2 15.96 16.56 2 11.50 13.23 2 10.86 14.26
3 26.90 14.96 3 12.20 13.82 3 17.28 15.75
4 19.07 18.70 4 17.79 12.48 4 15.06 16.46
5 16.81 19.16 5 11.24 17.10 5 13.37 17.77
6 16.42 22.67 6 11.94 22.70 6 17.28 21.00
7 13.98 20.27 7 15.06 15.26 7 16.15 15.28
8 15.95 21.80 8 13.85 18.67 8 20.88 17.00
9 27.97 12.48 9 18.20 10.00 9 20.14 14.75
10 15.26 10.64 10 16.36 11.71 10 11.73 12.67
All measured values not exceed allowed vibro-displacement value (100micrometers).
Also, vibration assessment with special software Vesta using was done.
Readings of the images 8 and 9 colors:Green normal condition;Yellow lightly loosening of pressure;Red high loosening of pressure.
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Progress report No. 1T-B Sheet 14
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Image 8. Results of vibration diagnosis at no-load
Image 9. Results of vibration diagnosis at load 45%.
Conclusion: It is possible a lightly loosening of pressure of the windings and tappingcore leg. Windings shall be pressed during repair.
SEC ZTZ-Service Co.
Progress report No. 1T-B Sheet 15
HV
side
LV
side
Main
core leg
Main
core leg
Tapping
core leg
Freecore leg
Freecore leg
HVside
LVside
Maincore leg
Maincore leg
Tappingcore leg
Freecore leg
Freecore leg
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