Progress Report No 1t-b

7/30/2019 Progress Report No 1t-b

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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: [email protected]://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

SEC ZTZ-Service Co.

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.



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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.



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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.


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



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.


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.



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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.

SEC ZTZ-Service Co.



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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.


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


PointNo


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

SEC ZTZ-Service Co.



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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


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.


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


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.

SEC ZTZ-Service Co.



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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.


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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Progress Report No 1t-b