TRANSFORMER DIAGNOSIS.pdf

(1)

© OMICRON 11/6/2014 Page: 1

TRANSFORMER DIAGNOSIS

(2)

Sources of Faults

W

in

d

in

g

C

o

re

B

u

sh

in

g

s

V

es

se

l

&

O

il

A

cc

es

so

ri

es

T

a

p

C

h

a

n

g

er

F

re

q

u

en

cy

i

n

%

Source: Cigre_WG 12-05 „An international survey on failures in large power

transformers in service“, Electra No. 88, 1983

(3)

© OMICRON 04.12.200411/6/2014 Page: 3

Gas-in-Oil Analysis

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

Type of Fault

Partial Discharge

Discharge with low

Energy

Discharge with high

Energy

Thermal Fault T<300°C

Thermal Fault T<700°C

(4)

Tests for Diagnosis

(Fault Location)

• Winding resistance and OLTC test

• Practical examples for winding ratio,

excitation current, leakage reactance

• FRSL

• Capacitance and dissipation factor

(5)

© OMICRON 04.12.200411/6/2014 Page: 5

Universal Transformer

Test System

Power Amplifier

15-400Hz

• Up to 2000A, 2kV AC / 400A DC

• Measurement of

• Ratio

• Complex Impedance

• Resistances

• …...

C-Tan

δδδδ

-Prüfsystem

(6)

(7)

© OMICRON 04.12.200411/6/2014 Page: 7

On-load tap changer principle (1)

Voltage Selector

Diverter

Switch

Commutating

Resistors

(8)

On-load tap changer principle (2)

Voltage Selector

Diverter

Switch

Commutating

Resistors

(9)

© OMICRON 04.12.200411/6/2014 Page: 9

On-load tap changer principle (3)

Voltage Selector

Diverter

Switch

Commutating

Resistors

(10)

On-load tap changer principle (4)

Voltage Selector

Diverter

Switch

Commutating

Resistors

(11)

© OMICRON 04.12.200411/6/2014 Page: 11

On-load tap changer principle (5)

Voltage Selector

Diverter

Switch

Commutating

Resistors

(12)

On-load tap changer principle (6)

Voltage Selector

Diverter

Switch

Commutating

Resistors

(13)

© OMICRON 04.12.200411/6/2014 Page: 13

(14)

Measurement of the static

resistance values of:

1) all internal contacts (diverter

switch contacts + tap

selector switch + connection

clamps) +

(15)

© OMICRON 04.12.200411/6/2014 Page: 15

(16)

Voltage selector switch in a good

condition

Widerstand V-Mp

235.00

240.00

245.00

250.00

255.00

260.00

265.00

270.00

275.00

280.00

285.00

1

2

3

4

5

6

7

8

9

1

0

1

2

1

3

1

4

1

5

1

6

1

7

1

8

1

9

2

0

2

1 Stufen

W

id

e

rs

ta

n

d

[

m

ΩΩΩΩ

]

_KEMA

OMICRON 1…21

Ref. Temp.

OMICRON 21…1

Ref. Temp.

(17)

© OMICRON 04.12.200411/6/2014 Page: 17

Influence of the Temperature

Maschinentransformator

27kV/400kV 1100MVA

1. Measurement: 20°C

(18)

Influence of the Temperature

R Winding (Tap)

0.14 _Ω

0.145 _Ω

0.15 _Ω

0.155 _Ω

0.16 _Ω

0.165 _Ω

000

005

010

015

020

025

030 Taps

A UP

A DOWN

B UP

B DOWN

C UP

C DOWN

012 .

1 *

)

20 (

)

23 (

:

235

235 )

(

)

(

1

2

1

2 °

=

°

+

=

Beispiel

R

T

R

T

R

Delta =1.2%

(19)

© OMICRON 04.12.200411/6/2014 Page: 19

(20)

(21)

© OMICRON 04.12.200411/6/2014 Page: 21

Defective Tap Selector

(22)

Resistance U-Mp

R L1 (referred to 20°C)

450.0 500.0 550.0 600.0 650.0 700.0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Taps m O h m R L1 1974 R L1 20.2.02 1...19 RL1 20.2.02 19…1

(23)

© OMICRON 04.12.200411/6/2014 Page: 23

100MVA 220/110 kV V

R L2 (referred to 20°)

450.0 470.0 490.0 510.0 530.0 550.0 570.0 590.0 610.0 630.0 650.0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Taps m O h m R L2 1974 R L2 20.2.02 1…19 R L2 20.2.02 19…1

(24)

100MVA 220/110 kV W

R L3 (referred to 20°)

450.0 470.0 490.0 510.0 530.0 550.0 570.0 590.0 610.0 630.0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Taps m O h m R L3 1974 R L3 20.2.02 1…19 R L3K 20.2.02 19…1

(25)

© OMICRON 04.12.200411/6/2014 Page: 25

Winding Resistance U-Mp After Repair

Resistance L1

450.0

470.0

490.0

510.0

530.0

550.0

570.0

590.0

610.0

630.0

650.0

1

2

3

4

5

6

7

8

9

1

0

1

2

1

3

1

4

1

5

1

6

1

7

1

8

1

9 Taps

R

e

s

is

ta

n

c

e

[

m

Ω

]

Ω

]

Ω

]

Ω

]

Factory Measurement

OMICRON 1…19

OMICRON 19…1

(26)

Delta R for U-Mp „UP“-„DOWN“

Resistance Differenz L1 Up-Down

-6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 1 2 3 4 5 6 7 8 9 ₁0 ₁1 2₁ ₁3 ₁4 ₁5 ₁6 ₁7 ₁8 ₁9 Taps R e s is ta n c e [ mΩ ] Ω ] Ω ] Ω ]

Resistance Differenz L1 Up-Down

-30.0

-20.0

-10.0

0.0

10.0

20.0

30.0

40.0

1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9

Taps

R

e

s

is

ta

n

c

e

[

m

Ω

]

Ω

]

Ω

]

Ω

]

Before repair

After repair

(27)

© OMICRON 04.12.200411/6/2014 Page: 27

Cleaning effect of OLTC movement

R Winding (Tap)

0.14 Ohm

0.15 Ohm

0.16 Ohm

0.17 Ohm

0.18 Ohm

0.19 Ohm

0.2 Ohm

0

5

10

15

20

Taps

A UP

A DOWN

B UP

B DOWN

C UP

C DOWN

R Winding (Tap)

0.14 Ohm

0.15 Ohm

0.16 Ohm

0.17 Ohm

0.18 Ohm

0.19 Ohm

0.2 Ohm

0

5

10

15

20

Taps

A UP

A DOWN

B UP

B DOWN

C UP

C DOWN

(28)

Increased contact resistance on a

diverter switch in phase A

R Winding (Tap)

0.13 Ohm

0.135 Ohm

0.14 Ohm

0.145 Ohm

0.15 Ohm

0.155 Ohm

0.16 Ohm

0.165 Ohm

0.17 Ohm

0.175 Ohm

0.18 Ohm

0

2

4

6

8

10

12 Taps

A UP

A DOWN

B UP

B DOWN

C UP

C DOWN

(29)

© OMICRON 04.12.200411/6/2014 Page: 29

(30)

Tap Changer in Delta

DC

(31)

© OMICRON 04.12.200411/6/2014 Page: 31

Measurement of a Winding 27 kV - 17 kA

with 100A Test Current

Meas. Result

=700

µΩ

(32)

(33)

© OMICRON 04.12.200411/6/2014 Page: 33

Analysis of the Transient

Switching Behavior of the

(34)

Transient signal of one switching

procedure in detail

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

Ripple

Slope

αααα

(35)

© OMICRON 04.12.200411/6/2014 Page: 35

(36)

Ripple of a diverter switch in a

good condition (1100MVA)

Ripple

0.0%

0.5%

1.0%

1.5%

2.0%

2.5%

000

005

010

015

020

025

030 Taps

A UP

A DOWN

B UP

B DOWN

C UP

C DOWN

(37)

© OMICRON 04.12.200411/6/2014 Page: 37

Slope of a diverter switch in a

good condition (1100MVA)

Slope

-0.6A/s

-0.5A/s

-0.4A/s

-0.3A/s

-0.2A/s

-0.1A/s

0.0A/s

000

005

010

015

020

025

030 Taps

A UP

A DOWN

B UP

B DOWN

C UP

C DOWN

(38)

Ripple on a Diverter Switch with

bouncing Contacts in Phase C

Ripple

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

35.0%

40.0%

45.0%

50.0%

0

2

4

6

8

10

12 Taps

A UP

A DOWN

B UP

B DOWN

C UP

C DOWN

(39)

© OMICRON 04.12.200411/6/2014 Page: 39

Slope on a Diverter Switch with

bouncing Contacts in Phase C

Slope

-1.8A/s

-1.6A/s

-1.4A/s

-1.2A/s

-1.0A/s

-0.8A/s

-0.6A/s

-0.4A/s

-0.2A/s

0.0A/s

0

2

4

6

8

10

12 Taps

A UP

A DOW N

B UP

B DOW N

C UP

C DOW N

(40)

Even Interruptions of 500us can

be detected

(41)

© OMICRON 04.12.200411/6/2014 Page: 41

Ripple = f (Time of Interruption)

Dauer der

Unterbrechnung

[ms]

Ripple mit

Unter-brechung [%]

Ripple ohne

Unter-brechung

[%]

Slope mit

Unter-brechung

[mA/s]

Slope mit

Unter-brechung

[mA/s]

0.5

4.12

1.00 -42

-2

1

4.64

1.00 -49.17

-2

10

32.96

1.00 -405.6

-2

1000

100.00

1.00 -1192

-2

Ripple OS Wicklung mit 0.5A Prüfstrom

0.00

20.00

40.00

60.00

80.00

100.00

120.00

0.1

1

10

100 1000

Time of Interruption [ms]

R

ip

p

le

[

%

]

Ripple mit

Unterbrechung

Ripple ohne

Unterbrechung

(42)

Slope = f (Time of Interruption)

Dauer der

Unterbrechnung

[ms]

Ripple mit

Unter-brechung [%]

Ripple ohne

Unter-brechung

[%]

Slope mit

Unter-brechung

[mA/s]

Slope mit

Unter-brechung

[mA/s]

0.5

4.12

1.00 -42

-2

1

4.64

1.00 -49.17

-2

10

32.96

1.00 -405.6

-2

1000

100.00

1.00 -1192

-2

Slope OS Wicklung mit 0.5A Prüfstrom

-1400

-1200

-1000

-800

-600

-400

-200

0

0.1

1

10

100 1000

Daue r de r Unte rbrechung [ms]

S

lo

p

e

[

m

A

/s

]

Slope mit

Unterbrechung

Slope ohne

Unterbrechung

(43)

© OMICRON 04.12.200411/6/2014 Page: 43

Ripple of an aged diverter switch

Ripple

3.0%

3.5%

4.0%

4.5%

5.0%

5.5%

0

5

10

15

20 Taps

A UP

A DOWN

B UP

B DOWN

C UP

C DOWN

(44)

Slope of an aged diverter switch

Slope

-1.1A/s

-1.05A/s

-1.0A/s

-0.95A/s

-0.9A/s

-0.85A/s

-0.8A/s

-0.75A/s

-0.7A/s

-0.65A/s

-0.6A/s

0

5

10

15

20 Taps

A UP

A DOWN

B UP

B DOWN

C UP

C DOWN

(45)

© OMICRON 04.12.200411/6/2014 Page: 45

(46)

Contact Problems (static)

Ripple

0.0%

2.0%

4.0%

6.0%

8.0%

10.0%

12.0%

14.0%

16.0%

18.0%

000

005

010

015

020

025

030

Taps

A UP

A DOWN

B UP

B DOWN

C UP

C DOWN

005 0.145044615Ω

0.061%

2.601%

-1.75A/s

20.0A

2.9008923V

006 0.14168819Ω

0.046%

2.253%

-1.65A/s

20.0A

2.8337638V

007 0.142732395Ω

0.069%

2.701%

-1.75A/s

20.0A

2.8546479V

008 0.139659045Ω

0.097%

2.903%

-1.69A/s

20.0A

2.7931809V

009 0.13919992Ω

4.612%

16.975%

-11.37A/s

20.01A

2.7853904V

009 0.1396798Ω

1.028%

14.25%

-2.6A/s

20.0A

2.793596V

009 0.139666415Ω

0.204%

14.7%

-1.75A/s

20.0A

2.7933283V

009 0.13958899Ω

0.174%

15.7%

-0.56A/s

20.0A

2.7917798V

010 0.13754698Ω

0.059%

15.666%

-1.91A/s

20.0A

2.7509396V

011 0.137932135Ω

0.055%

3.402%

-1.75A/s

20.0A

2.7586427V

012 0.13525902Ω

0.086%

2.703%

-1.69A/s

20.0A

2.7051804V

013 0.12915814Ω

0.079%

3.4%

-2.62A/s

20.0A

2.5831628V

Ripple

(47)

© OMICRON 04.12.200411/6/2014 Page: 47

Contact Problems (static)

Slope

-12.0A/s

-10.0A/s

-8.0A/s

-6.0A/s

-4.0A/s

-2.0A/s

0.0A/s

000

005

010

015

020

025

030

Taps

A UP

A DOWN

B UP

B DOWN

C UP

C DOWN

005 0.145044615Ω

0.061%

2.601%

-1.75A/s

20.0A

2.9008923V

006 0.14168819Ω

0.046%

2.253%

-1.65A/s

20.0A

2.8337638V

007 0.142732395Ω

0.069%

2.701%

-1.75A/s

20.0A

2.8546479V

008 0.139659045Ω

0.097%

2.903%

-1.69A/s

20.0A

2.7931809V

009 0.13919992Ω

4.612%

16.975%

-11.37A/s

20.01A

2.7853904V

009 0.1396798Ω

1.028%

14.25%

-2.6A/s

20.0A

2.793596V

009 0.139666415Ω

0.204%

14.7%

-1.75A/s

20.0A

2.7933283V

009 0.13958899Ω

0.174%

15.7%

-0.56A/s

20.0A

2.7917798V

010 0.13754698Ω

0.059%

15.666%

-1.91A/s

20.0A

2.7509396V

011 0.137932135Ω

0.055%

3.402%

-1.75A/s

20.0A

2.7586427V

012 0.13525902Ω

0.086%

2.703%

-1.69A/s

20.0A

2.7051804V

013 0.12915814Ω

0.079%

3.4%

-2.62A/s

20.0A

2.5831628V

Slope

(48)

Measurement of the short

circuit impedance

(49)

© OMICRON 04.12.200411/6/2014 Page: 49

Short circuit impedance

220kV Winding

220kV

Forces

10kV Winding

220kV Winding

Leakage

Flux

(50)

(51)

© OMICRON 04.12.200411/6/2014 Page: 51

400kVA transformer

Template:

TR Short Circuit Imp.

Version:

1.40 3 Phase Measurement

Uk [V]

Ik [A]

P [W]

f [Hz]

Z [OHM]

Phi [°]

R [OHM]

X [OHM]

L [H]

1479.40

8.89 6270

50 288.2335 74.02338 79.33485 277.1002 0.882037449

Phase A

f [Hz]

Z [OHM]

Phi [°]

R [OHM]

X [OHM]

L [H]

50 287.8106 74.21368 78.29901 276.9553 0.881576072

Difference to Factory Test [%]

-0.14671 0.257084

-1.30566

-0.05231

-0.05230818

Phase B

f [Hz]

Z [OHM]

Phi [°]

R [OHM]

X [OHM]

L [H]

50 287.9643 73.82169 80.23478 276.5607 0.880319891

Difference to Factory Test [%]

-0.09342

-0.27247 1.134345

-0.19473

-0.19472629

Phase C

f [Hz]

Z [OHM]

Phi [°]

R [OHM]

X [OHM]

L [H]

50 288.7539 74.01075 79.53928

277.583 0.883574133

Difference to Factory Test [%]

0.180545

-0.01706 0.257675

0.17422

0.174219805

Average Difference to Factory Test [%]

-0.01986

-0.01082 0.028788

-0.02427

-0.02427155

(52)

Measurement of the short circuit

impedance

b) Measurement of the AC-short circuit resistance

(FRSL = Frequency response of stray losses)

(53)

© OMICRON 04.12.200411/6/2014 Page: 53

Parallel strands without twisting

B

HV Winding

LV Winding

Losses

by induced

currents

(54)

Parallel strands with twisting

Induced

currents are

compensated

B

HV Winding

LV Winding

(55)

© OMICRON 04.12.200411/6/2014 Page: 55

B

HV Winding

LV Winding

Additional

losses

by induced

currents

(56)

(57)

© OMICRON 04.12.200411/6/2014 Page: 57

(58)

Comparison of the 3 phases

R(f)

0.0 Ohm

0.5 Ohm

1.0 Ohm

1.5 Ohm

2.0 Ohm

2.5 Ohm

3.0 Ohm

3.5 Ohm

4.0 Ohm

4.5 Ohm

0

100

200

300

400

500 Frequency (Hz)

A

B

C

(59)

© OMICRON 04.12.200411/6/2014 Page: 59

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%).

(60)

Case study

(61)

© OMICRON 04.12.200411/6/2014 Page: 61

Case study

40-MVA, Y

∆∆∆∆

, 121 kV/12.85 kV transformer

Phase A: eight of the 13 parallel strands of this winding had been

short-circuited. 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

(62)

(63)

© OMICRON 04.12.200411/6/2014 Page: 63

(64)

Diagnosis of a damaged

transformer 220kV / 110kV / 10kV

• Short circuit of the 10kV

winding by a marten

•Short circuit current I

_s

= 52

kA

•Switching “off” time about

100ms

Result:

Short circuit of the 10kV

(65)

© OMICRON 04.12.200411/6/2014 Page: 65

Ratio and excitation current

Ratio Error

= -21.5% !

(66)

L

_k

=f(f)

Faulty

winding

(67)

© OMICRON 04.12.200411/6/2014 Page: 67

Defective 10kV winding

skin-effect in the core

Low Frequencies

(68)

R

_k

=f(f)

Rk 110kV - 10kV

0.00

5.00

10.00

15.00

20.00

25.00

30.00

0

100

200

300

400 f [Hz]

O

h

m

s

Rk [Ohm] U

Rk [Ohm] W

Rk [Ohm] V

(69)

© OMICRON 04.12.200411/6/2014 Page: 69

FRA phases V und W

Phase: V

(70)

FRA Phases U und W

Phase: W

Phase: U

(71)

© OMICRON 04.12.200411/6/2014 Page: 71

Opened Transformer

Defective

Phase

Current

limiting

coils

(72)

View from the Top

10 kV

110 kV

(73)

© OMICRON 04.12.200411/6/2014 Page: 73

(74)

View from the Top

(75)

© OMICRON 04.12.200411/6/2014 Page: 75

CAPACITANCE AND TAN DELTA

MEASUREMENTS ON

(76)

Definition of Tan Delta

Equivalent Parallel Circuit Diagram and Vector Diagram

with

and

_Frequency

(77)

© OMICRON 04.12.200411/6/2014 Page: 77

Equivalent Serial Circuit Diagram

R

_R

_S

S

C

_S

U

_Rs

U

_Cs

S

C

R

_R

_C

U

ω

δ

=

tan

Mainly polarization losses

(78)

Frequency Curves for Serial and Parallel Circuit Diagram

0.00E+00

1.00E-03

2.00E-03

3.00E-03

4.00E-03

5.00E-03

6.00E-03

7.00E-03

8.00E-03

0

100

200

300

400

500 Serial

Parallel

Sum

(79)

© OMICRON 04.12.200411/6/2014 Page: 79

Transformer Winding Insulation

b. Model for the

behaviour of a

dielectric with

polarisation

characteristic and

conductivity

d. Simplified geometry

model for the main

components oil,

barriers and spacers

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

e: Dielectric model

for the insulation

system of power

transformers

(80)

Tan Delta (f) Pressboard Dependent

on the Water Content

(81)

© OMICRON 04.12.200411/6/2014 Page: 81

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

(82)

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)

(83)

© OMICRON 04.12.200411/6/2014 Page: 83

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

(84)

Schering Bridge (1919)

First application for insulation diagnosis 1924

Has to be balanced

for each frequency

(85)

© OMICRON 04.12.200411/6/2014 Page: 85

Measuring Principle of CP TD1

u

Re

U

X

(t)

U

N

(t)

Z

1 Z

2 Z

X

C

X,

L

X

Z

N

C

_N

0 (t)

Reference path

Measurement path

I

CN

I

CX

Im

ϕ

δ

Uo

Icx

rad

in

,

2 cos

tan

:

1 with

L

ϕ

δ

ϕ

π

δ

ϕ

δ

−

=

≅

<<

Icn

Good solution for the automatic measurement at

different frequencies

(86)

Universal Transformer Test and

Diagnosis System

Power amplifier 15-400Hz

• Outputs up to 2000A, 2kV AC / 400A DC

• Measurement of

• Ratio

• Complex Impedance

• Resistance

• …...

(87)

© OMICRON 04.12.200411/6/2014 Page: 87

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 !

(88)

B_1 B_PE B_2 b o o s te r-In te rf a c e CN safety calib ADC DSP RS232 & supply

CPC100

mains FUNCTIONAL EARTH In A In B

High voltage output (0..12kV)

CP TD1

voltage-booster

Tan

δ

- measurement with CP DF12

Monday, 01. July 2002 Ix_in guard primary sec. tertiary s e ri a l-In te rf a c e

EUT (Cx)

select channel

Relay matrix for

7 different measuring

modes without rewiring:

UST-A, UST-B, UST A+B

GST,

GSTgA, GSTgB,

GSTgA+B

(89)

(90)

C-Tan-Delta

Measurement on

Power

Transformers

High Voltage Winding

Tapped Winding

Core

400kV Bushing

Measuring Tap

Low Voltage

Bushing

(91)

Transformer Winding Test

(92)

Test Procedure for a

3-Windings Transformer

(93)

Tan Delta (f) with treated (dry) oil

DF (f) H, HL, L

0.0 %

0.05 %

0.1 %

0.15 %

0.2 %

0.25 %

0.3 %

0.35 %

0.4 %

0.45 %

0 .0

H

z

5

0 .0

H

z

1

0

0 .0

H

z

1

5

0 .0

H

z

2

0

0 .0

H

z

2

5

0 .0

H

z

3

0

0 .0

H

z

3

5

0 .0

H

z

4

0

0 .0

H

z

4

5

0 .0

H

z

H(f)

HL(f)

L(f)

(94)

Tan Delta (f) with aged oil

DF (f) H, HL, L

0.0 %

0.1 %

0.2 %

0.3 %

0.4 %

0.5 %

0.6 %

0 .0

H

z

5

0 .0

H

z

1

0

0 .0

H

z

1

5

0 .0

H

z

2

0

0 .0

H

z

2

5

0 .0

H

z

3

0

0 .0

H

z

3

5

0 .0

H

z

4

0

0 .0

H

z

4

5

0 .0

H

z

H(f)

HL(f)

L(f)

(95)

Tan Delta (f) of a 110kV transformer with

high water content

DF (f) H, HL

0.0 %

0.2 %

0.4 %

0.6 %

0.8 %

1.0 %

1.2 %

1.4 %

1.6 %

1.8 %

0 .0

H

z

5

0 .0

H

z

1

0

0 .0

H

z

1

5

0 .0

H

z

2

0

0 .0

H

z

2

5

0 .0

H

z

3

0

0 .0

H

z

3

5

0 .0

H

z

4

0

0 .0

H

z

4

5

0 .0

H

z

H(f)

HL(f)

(96)

Tan Delta 11kV-0.4kV 800KVA (1966)

DF HV-LV (f)

0.0 %

0.5 %

1.0 %

1.5 %

2.0 %

2.5 %

0.0 Hz

50.0 Hz

100.0 Hz

150.0 Hz

200.0 Hz

250.0 Hz

(97)

Unexpected ferquency curves

-1.0 %

0.0 %

1.0 %

2.0 %

3.0 %

4.0 %

5.0 %

6.0 %

7.0 %

8.0 %

0.0 Hz

100.0 Hz 200.0 Hz 300.0 Hz 400.0 Hz 500.0 Hz

17.0 Hz

30.0 Hz

80.0 Hz

130.0 Hz

230.0 Hz

400.0 Hz

220kV Gießharzdurchführungen

0.4 % 0.45 % 0.5 % 0.55 % 0.6 % 0.65 % 0.7 % 0.75 % 0.8 % 0.0Hz 50.0Hz 100.0H z 150.0H z 200.0H z 250.0H z 300.0H z 350.0H z 400.0H z 450.0H z

Phase A

Phase B

Phase C

DF (f)

-1.5 % -1.0 % -0.5 % 0.0 % 0.5 % 1.0 % 0 .0 H z 5 0 .0 H z 1 0 0 .0 H z 1 5 0 .0 H z 2 0 0 .0 H z 2 5 0 .0 H z 3 0 0 .0 H z 3 5 0 .0 H z 4 0 0 .0 H z 4 5 0 .0 H z

(98)

Phases Not Connected or Bad Contacts

Currents through

the windings

cause additional

inductive losses

(99)

Phases Connected

All phases of the

windings are on

the same potential

(100)

Bad contact of

short circuit

DF (f)

-1.5 % -1.3 % -1.1 % -0.9 % -0.7 % -0.5 % -0.3 % -0.1 % 0.1 % 0.3 % 0.5 % 0.7 % 0 .0 H z 5 0 .0 H z 1 0 0 .0 H z 1 5 0 .0 H z 2 0 0 .0 H z 2 5 0 .0 H z 3 0 0 .0 H z 3 5 0 .0 H z 4 0 0 .0 H z 4 5 0 .0 H z

DF (f)

0.0 % 0.1 % 0.2 % 0.3 % 0.4 % 0.5 % 0.6 % 0.7 % 0.8 % 0 .0 H z 5 0 .0 H z 1 0 0 .0 H z 1 5 0 .0 H z 2 0 0 .0 H z 2 5 0 .0 H z 3 0 0 .0 H z 3 5 0 .0 H z 4 0 0 .0 H z 4 5 0 .0 H z

Good contacts

of short circuit

(101)

HV Bushings

(102)

Capacitive Bushings (1)

E

_max

= high

A

E

_max

=

smaller

A

without

capacitive

layers

with

capacitive

layers

Earthing Cap

(103)

(104)

(105)

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

-5

0

5

10

15

20

25

30

75

77

79

81

83

85

87

89 Date of Measurement

T

a

n

D

e

lt

a

x

1

0

-3

C

h

a

n

g

e

o

f

C

a

p

a

c

it

a

n

c

e

%

Tan Delta

Change of Capacitance

(106)

(107)

(108)

(109)

(110)

220kV RIP Bushing stored outside

0.25 %

0.35 %

0.45 %

0.55 %

0.65 %

0.75 %

0.85 %

0.0 Hz

100.0 Hz

200.0 Hz

300.0 Hz

400.0 Hz

500.0 Hz

T

a

n

D

e

lt

a

31.03.2004

15.07.2004

08.10.2004

Minimum

(111)

(112)

DF (f) 69 kV OIP Bushings

Circuit Breaker Bushing C-PF Test

V TEST

*

[V]

C meas.

PF meas.[%]

10032.20

2.836E-10

0.457 10031.81

2.815E-10

0.491 10031.55

2.853E-10

0.493 10031.20

2.837E-10

0.486 10028.73

2.855E-10

0.504 10030.49

2.853E-10

0.449

(113)

DF (f) 69 kV OIP Bushings 60Hz

0.0 %

0.1 %

0.2 %

0.3 %

0.4 %

0.5 %

0.6 %

*0.0 Hz

100.0 Hz 200.0 Hz 300.0 Hz 400.0 Hz *500.0 Hz

1

2

3

4

5

6

(114)

(115)

OIP bushings 420kV (1994)

Tan Delta

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0

100

200

300

400 Hz

%

U

V

W

C

360

365

370

375

380

385

390

395

400

405

410

415

0

100

200

300

400 Hz

p

F

U

V

W

+ 10%

(116)

Defectice 110 kV RPB Bushing

Tan Delta

0.3 0.5 0.7 0.9 1.1 1.3 1.5 0 100 200 300 400 Hz % 2U 2V 2W 2N 1N

C

300 305 310 315 320 325 330 335 340 0 100 200 300 400 Hz p F 2U 2V 2W 2N 1N

Tan Delta (f)

C (f)

(117)

Defectice 110 kV RPB Bushing

Tan Delta (V)

Tan Delta (U)

0.3

0.35

0.4

0.45

0.5

0.55

0.6

0.65

0.7

0.75

0

5

10

15 kV

%

2V

2N

(118)

Tan Delta (U)

0.0%

0.05%

0.1%

0.15%

0.2%

0.25%

0.3%

0.35%

0.4%

0.45%

0.5%

0.0V

2000.0V

4000.0V

6000.0V

8000.0V 10000.0V 12000.0V 14000.0V

U TanDelta

V TanDelta

W TanDelta

Spannungsverläufe unauffällig

(119)

Suspicious 400 kV OIP Bushings (1998)

Reason ?

Tan Delta (V)

0.37%

0.39%

0.41%

0.43%

0.45%

0.47%

0.49%

0.0 Hz

50.0 Hz

100.0 Hz

150.0 Hz

200.0 Hz

250.0 Hz

300.0 Hz

350.0 Hz

U TanDelta

V TanDelta

W TanDelta

Frequenzververläufe auffällig

(120)

Suspicious 123 kV RIP Bushing

Reason ?

0.0%

0.1%

0.2%

0.3%

0.4%

0.5%

0.6%

0.7%

0.8%

0.0 Hz

100.0 Hz 200.0 Hz 300.0 Hz 400.0 Hz 500.0 Hz

T

a

n

D

e

lt

a

73

80

(121)

Measurement with high interference

Durchführung

Erdungsgarnitur

HS Anschluss

(122)

(123)