Doble - Water in Liquid Filled Electrical Equipment

8/19/2019 Doble - Water in Liquid Filled Electrical Equipment

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Water in Liquid-Filled

Electric Apparatus

Paul Griffin

Lance Lewand

Doble Engineering Company

n i

Confidential Notice

Doble Engineering (Doble) hereby grants the recipient (you) theright to retain this presentation and materials included within (thePresentation) for private reference. No other rights, title, orinterest, including, but not limited to, the rights to copy, makeuse of, distribute, transmit, display or perform in public (or tothird parties), edit, translate, or reformat any portion of thePresentation are hereby or otherwise granted and shall remain

expressly reserved by Doble. You acknowledge and agree thatsuch limited license is expressly conditioned upon youracceptance of the terms herein. You further agree that, in theevent of your breach, Doble will suffer irreparable damage andinjury for which there is no adequate remedy at law. As such,Doble, in addition to any other rights and remedies available,shall be entitled to seek injunction by a tribunal of competent jurisdiction restricting you from committing or continuing anybreach of these terms.


2/68

Water in Dielectric Liquids

Source, State, and

Measurement

D o b l e

Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009

Where Water Located

• Most of the water is located in the solid

cellulosic insulation (reservoir for water)

– Wood

– Paper

– Pressboard

• The amount in the oil isoften


3/68


Entry Points for Water in Transformers

• Residual after processing:

– Manufacturing

– Installation

– Maintenance

• Leaks, Through Weak Points of Transformer

• Transformer Preservation System

– Ineffective dryers - breathing conservators

– Ruptured bladder/diaphragm - sealed conservators

• Byproduct of Cellulosic Degradation

E n

o m p a

n y


Water Ingress Points

-

1

2

-

2

10

Gauges and Plugs

Valves

Bushing Gaskets

Cooler Plugs

Lid Gasket

Cooler Gaskets

and Valves

Electrode Shaft

Manhole Gaskets

Maintain Pressure

D o E n g i n

r i n o

a


4/68


Leak through Bushing


States of Water

• Dissolved Water – Water in solution interspersed between hydrocarbon molecules

• Emulsified Water – Water that is suspended as clusters of water molecules. It gives

oil a cloudy, milky appearance

• Free Water

– Water that is not in solution and is in high enough concentration toform water droplets and separate from the oil.

• Trapped Water – Water held on non-cellulosic surfaces due to surface chemistry

• Bound Water – Water held in polar oil/paper degradation byproducts

e e r i n g

o


5/68


Water Adhesion to Metal Surfaces

• Adhesion considered adsorption (not

absorption) in this case

• Intermolecular Interactions

– dipole-dipole (+ end of polar to - end of polar),

hydrogen bonding

– dipole induced dipole

– electrostatic interactions

• Surface Tension

m p a n y


Trapped Water - Core Steel

DRY

WET (white bumps arewater droplets being

charged by the SEM)

o

p


6/68


Tank Steel

Unpainted Painted

g


States of Water

Free Water

Dissolved Water Emulsified Water

i


7/68


Determination of Water Concentration

Performed By Karl Fischer titration using ASTM

Method D 1533 or IEC Method 60814

wt wt ppmoilg

O H g/,2

g

i n e e r i n g

o m p a

n y


Solubility

• Solubility (100% Saturation) of water in oil is defined as

the amount of dissolved water an oil can hold at a

specific temperature

• Solubility changes significantly with temperature

• As the oil increases in temperature, the ability of the oil

to hold water also increases

• For example, solubility of water in oil at 10C is 36

ppm, whereas at 90C the solubility is 592 ppm

• As oils age and accumulate large amounts of acids

and other polar compounds solubility increases

o b l e

o


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Solubil ity of Water in Oil and

Silicone

Temp., C Oil (ppm) Silicone (ppm)

0 22 88

10 36 125

20 55 174

30 83 237

40 121 316

50 173 414

60 242 534

70 331 678

80 446 850

90 592 1052100 772 1287

80

D o b e E n

g i n e g

o m p


Water Solubil ity in Oil and Silicone

1

10

100

1000

10000

2.5 2.75 3 3.25 3.5 3.75 4

Temperature (1/K x 1000)

W a t e

r C o n t e n t , p p m

Oil (ppm)

Silicone (ppm)

0 C50 C100 C

D b l e E g i n e e

g


9/68


Water Solubil ity Calculation Equations

So = solubility of water in new oil at

a given temperature

0895.71567

K

S Log o e n g

o m p a

n y


Effects of Solubi lity Characteristics

Aromatic and Acid Content

S = EXP((16.2822-3698.27/T)+0.02589* Ar +2.0991* An)

S = Solubility of Water in Oil, ppm

T = Absolute temperature, K

Ar = Aromatic content in % (IEC 60590)

An = Neutralization number, mg KOH/g oil (IEC 62021-1)

• Similar to Doble data with 12% aromatic content and 0.01 Acidity

• E. S. Mladenov, St. G. Staykov, and G. St. Cholakov

IEEE Electrical Insulation Mag. Vol 25, No.1 Jan/Feb 2009

D o b

o m p a n y


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Effects of Aromatic Content on Water

Solubility Characteristics

0

100

200

300

400

500

600

700

800

900

0 20 40 60 80 100 120

Temperature, C

W a

t e r

C o n

t e n

t , p p m

.

2

6

12

Aromatic Content , %

E. S. Mladenov, St. G. Staykov, and G. St. Cholakov

IEEE Electrical Inuslation Mag. Vol 25, No.1 Jan/Feb 2009

D o b l e E

n g i n e e i

n g


Effects of Acidity on Water Solubili ty

Characteristics

0

100

200

300

400

500

600

700

800

900

0 20 40 60 80 100 120

Temperature, C

W a t e r C o n t e n t , p p m

0.01

0.05

0.1

E. S. Mladenov, St. G. Staykov, and G. St. Cholakov

IEEE Electrical Inuslation Mag. Vol 25, No.1 Jan/Feb 2009

Aci di ty , mg KOH/g

D o b l e E n g i n e e

r n g

p a n y


11/68


Relative Saturation, % (%RS)

Relative saturation is the amount of water measured in the oil in

relation to the solubility level at that temperature (T)

Concentration at T1

Solubility at T1x 100% o b e

r i n g o

m p a n y


Relative Saturation, % (%RS)

Relationship of:

what is measured

How much water can be dissolved

in the oil at that temperature

To b l e E n g i n e e

r i n

p a y


12/68


For Example

• An oil sample was taken from a

transformer at 85C and tested for water

content and the result was 30 ppm

• To determine the relative saturation, 30

ppm would be divided by the solubility

level at 85C which is 517 ppm multiplied

by 100 (30 ppm/517 ppm x 100)

• Relative Saturation = 5.8%

o


Low %RS and High %RS Oil

Temperature, 50°C

Low RS

Visual Appearance is Clear

Temperature, 0°C

High RS

Visual Appearance is

Cloudy

Water Content

30 ppm

Water Content

30 ppm

, i

a n y


13/68

Sampling of Dielectric Liquidsfor Water Content

D o b l e E

n g i n e e r

o m p


Key Points• A specimen that is representative of the bulk liquid

insulation

• When to sample - Ideal

– When the units is above 50-60C top oil temperature

– When the temperature of the transformer is fairly stable or

increasing moderately

– When the air humidity is low• Where to sample

– Bottom drain value most common except for fluids with

density greater than 1.0 (where free water is found)

– Other valves are generally acceptable

• Report top oil temperature at time of sampling

e r


14/68


Practices - Sampling Insulating Liquids

• Doble Reference Book (Insulating Liquids and Gases)

• Doble sampling guides on website:http://www.doble.com/services/lab_services_testing.html

• ASTM D 923: Standard Practice for Sampling

Electrical Insulating Liquids

• IEC 60475: Method of Sampling Liquid Dielectrics

• IEC 60567: Guide for the Sampling of Gases and of

Oil from Oil-filled Electrical Equipment and for the

Analysis of Free and Dissolved Gas

n


Containers

Plastic - there are

no acceptable plastic

containers

D o b l e E n g i n e e

r i


15/68


Preferred Container - Glass Syringes


Acceptable Bottles - Glass and Metal

n e e

r i

n g

g p a n

y


16/68


Key Sample Preparation

Clean valve and remove stagnant oil

• Open drain plug, wipe out valve with lint free cloth• Reinstall drain plug and flush out sampling cock

• Close valve, remove drain plug and catch oil

• Install bushing adapters (brass, iron) to hose barb

• Flush at least 2 to 4 liters of oil through valve

• Then take sample

o


Major Cause of Contamination -

Water in the Valve

Tip: a quick flush pr ior to taking sample greatly

reduces the amount of oil required to flush Keep the water

out of the valve

n y


17/68


Adapter


Taking the Sample• Fill without causing aeration

– Moderate rate

– On sides of container

• Bottles - f ill to about 1” of top and seal

• Cans, Steel Cylinders - f ill to overflowing andseal

• Syringes

– Flush to wet barrel and plunger

– Remove gas bubbles immediately and then fill

D o b

e r i n

n y


18/68


Sampling QC Procedure

• Special QC Procedures

– Use of portable water sensor such as DOMINO

Drain Valve

Water Sensor Manifold

Water Sensor

Tubing for liquid

sample

i e e

o


Experiment

• 17 Transformers

• Voltage levels – 115kV, 23kv and 13kV

• Prior test indicated 10ppm to free H2O

• Units previously tested

(1 to 12 months prior)• 2” Valves

• Tested again 6 months later on 5 transformers


19/68


Results – Portable (Field) vs

Laboratory (Karl Fischer Titration)

Domino vs. Laboratory results

0

10

20

30

40

50

60

70

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Sample #

p p m w a

t e r

Domino

Lab ppm

Excellent correlation – 1.88ppm diff between Domino and Lab

o l e E

i n e e r i

o m p


How Much Oil Needs to be Drained?

Volume of drained

0

0.51

1.5

2

2.5

3

3.5

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Sample #

Q u a r t s

Approx. 1.97 quarts to

reach equilibrium

Average 23ppm change from opening valve to taking sample

i n

i a n


20/68


Sample Comparison - ppm at start of test

0

10

20

30

40

50

1 2 3 4 5

Transformer

p p m

- w a

t e r

10/01/2004

04/08/2005

Much drier at start of test second t ime around

Good flushing in first test and then well sealed

o l n

e e r i o

m p a


Sample Comparison - Quantity of Oil Drained

0

0.5

1

1.5

2

2.5

3

1 2 3 4 5

Transformer

Q

u a r t s

10/01/2004

04/08/2005


reach equilibrium


reach equilibriumvs.

n g i e

r i n o

m p a n


21/68


What Temperature To Use

• Doble Materials Laboratory arranged with Reliant

Energy in Pennsylvania to take temperatures atvarious places on a transformer during sampling

• Reason for Undertaking

– Part of method used to calculate relative saturation

and water content of paper

– Doble recommends taking top oil

– Standards differ in their approach

i n g o


Transformers Temperature Gradients -

What to Use for Equilibrium Calculations

• Method Employed and Parameters Chosen

– Used a laser guided infrared thermometer to take

readings, error was ± 1°C

– Top oil versus bottom oil

– Tank versus drain valve

– Convection cooling versus pumped cooling – Different manufacturers

– All transformers were power plant transformers

– Transformers located in Ohio, PA, NJ, CT (61 units)

n

n g o m p

a n y


22/68


Temperature Reading Points

-

1

2

-

2

1

0

Gauges and Plugs

Valve

Reading using gauge and

infrared thermometer at top oil

Top oil gauge read very close to laser

guided infrared thermometer,

usually within 1 or 2°C

Reading taken on tank

directly behind valve

Reading taken on valve

body before and after

sampling

Sample Oil Reading

D e

i n e r i n

m p a

n


Temperature Averages, °C

Averages TopOil

BottomXFMRTank

OilSample

T-B

B-Oil

All XFMRs 43.82 31.54 33.79 12.28 +2.25

No Pumps 40.45 26.92 21.00 13.53 -5.92

Pumps Off 57.53 43.50 14.03

Pumps On 60.00 53.42 49.14 6.58 -4.28

Largest 73.0 31.7 41.8

Smallest 41.0 44.4 -3.4

b

e e


23/68


Temperature Profi le - Typical

15

25

35

45

55

65

75

85

Top Oil Tank Behind Drain

Valve

Drain Valve

Before Samping

Drain Valve After

Sampling

Sample

T e m p e r a t u r e

Pumped Cooled Unit

Convection Cooled units

D b l e E

n g i n e e r i

n g


Top Oil Versus Oil Sample, °C

Top Oil Oil Sample

No Pumps 39.83 21.00 18.83

Pumps On 60.00 49.14 10.86 i n e

m


24/68


Temperature Reading Points, Pumps

78°C

Valve

55.7°C62.7°C

60.0°C

30 ppm

7.09% RS

12.36% RS

1.48% water in paper

68.2°C9.53% RS



D o b l e E

n g i n e e r i

n g o

y



25/68

Importance of Water inTransformers

D o b l e E

n g i n e e r i

n g o m p

y


Importance of Water in Transformers

• Dielectric breakdown voltage of the

insulation system

• Susceptibility to high relative saturation of

water in oil and formation of free water

• Ability to overload – Temperature water vapor bubbles evolve

from solid insulation a function of its water

content

• Aging of the solid insulation directly

proportional

H2O

g i n e e

r


26/68


Dielectric Strength

• Substantially lowered when:

– Water content of paper/pressboard is 2 to 4% or higher

– Relative Saturation of liquid dielectric is greater than

50%

D o b l e E

n g i n e e r i

n g n


Dielectr ic Strength & Water Content

of Mineral Oil

0

4

8

12

16

20

24

28

32

36

40

44

48

0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60

Water Content, ppm. wt./wt.

D i e l e c t r i c B r e a k d o w n V o l t a g e , k V

o b l e E n

o n


27/68


Dielectr ic Strength and %RS of

Mineral Oil

0

4

8

12

16

20

24

28

32

36

40

44

48

0 10 20 30 40 50 60 70 80 90 100

Water Content, % RS @22 C

D i e l e c t r i c B r e a k d o w n V o l t a g e , k

D o b l e E

n g i n e e i

n g o m p

a n y


Relationship Between Relative Saturation

and Dielectric Strength

0

5

10

15

20

25

30

35

40

45

50

01020304050

Temperature, Deg. C

R e l a t i v e S a t u r a t i o n ,

%

10

15

20

25

30

35

40

45

50

D i e l e c ,

k V / W a t e r , p p m

%RS Water in oil, ppm Dielectric Brkdwn. Voltage, kV

Figure from H. Azizian et al., Doble Conf., 1997, Sec. 5-8.8

D o b l e E n g

r i n g o

m p


28/68


Temperature Cycling - Dry Insulation

0

10

20

30

40

50

60

70

80

90

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360Elapsed Time, Hours

M e a s u r e

d R e

l a t i v e

S a

t u r a

t i o n ,

%

0

10

20

30

40

50

60

70

80

90

%RS

Temp.

T em p er a t ur e ,D e gr e e C

At 80C estimated water in paper 2.1%

D o b l e E

n i e r i

g p

y


Temperature Cycling - Wet Insulation

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360

Elapsed Time, Hours

M e a s u r e d R

e l a t i v e S a t u r a t i o n i n O i l ,

0

10

20

30

40

50

60

70

80

90

100

%RS

Temp.

em p er a t ur e ,D e gr

e e C

At 80C estimated water in paper 4.6%

o b l e n e

n g m

n


29/68


Temperature Cycling in Lab Model

0

20

40

60

80

100

120

140

0 100 200 300 400 500 600

Elapsed Time (Minutes)

T e m p .

R S ,

P P M

RS, %

T, °C

H2O, ppm

o b l e E n g

i n n g

o m p a n y


Temperature Cycling, Heating Up

0

20

40

60

80

100

120

0 30 60 90 120 150 180 210

T e m p

, R S , P P M

RS, %T, °C

H2O, ppm

o b e

o m p a n y


30/68


Temperature Cycl ing, Cooling Down

0

20

40

60

80

100

120

205 235 265 295 325

T e m p ,

R S

, P P M

RS, %

T, °C

H2O, ppm

D o b l e E

n g e e r i

n p a n

y


Temperature Cycl ing, Stabilizing

0

20

40

60

80

100

120

325 375 425 475 525 575 625

T e m p ,

R S

, P P M

RS, %

T, °C

H2O, ppm

D l e E n

i n g o m p

a n y


31/68


Bubble Evolution

Primarily Influenced by Water Content of Paper

Emergency Loading to Hot-Spot Temperature

Operate Below Water in Paper Content

180C


32/68


Bubble Evolution Temperature Versus

Water in Paper and Gas Content in Oil

2%

3%

1995 Doble Conf, Sec 8-5

T. V. Oommen, E. M.

Petrie, and S. R. Lindgren

o b g

i n e

m p a n y


Rate of Paper Aging

Time

0.5%

1.0%

As the water content of the cellulosic insulation

doubles, it halves the life

Directly proportional to the water content of the

cellulose

D o b l i n e e


33/68

Estimating The Moisture Contentof Paper Insulation

Lance Lewand, Doble Engineering Company

D o b l e E

n g i n e e r

o m p


Water Equilibration With Gas Space

• Pure Water

– Equilibrium (saturation) vapor pressure of pure water

is well defined as a function of temperature

– Relative humidity =

• vapor pressure/equilibrium vapor pressure

• at a given temperature expressed as a percentage

e e r i n g


34/68


Equilibrium Vapor Pressure

The vapor pressure of a liquid is the equilibrium pressure of a vapor above its liquid

(or solid) that is, the pressure of the vapor resulting from evaporation of a liquid

(or solid) above a sample of the liquid (or solid) in a closed container

D o n

i n e

p a n o


Vapor Pressure of Water

o b l e E n g i n e e

r i n g o

m p a n y


35/68


Water Equilibration

• Water in Gas Space and Oil

– Relative humidity = Relative saturation if Isothermal

• Water in gas space can be correlated with

water in paper (Piper Curves), new

equilibrium curves


Equilibrium Vapor Pressure Chart

(Fessler Curves - Water in Paper)

0.01

0.1

1

10

100

1000

0 10 20 30 40 50 60 70 80 90 100

Temperature, C

V a p o r P r e

s s u r e , m m

H g

.

0.50%

1.00%

1.50%

2.00%

2.50%

3.00%

3.50%

4.00%

4.50%

5.00%

0.5%

1.0%

5.0%

Water in Paper

%


36/68


Water in Transformers - Equilibrium

Curves

• Water content of oil and paper are related and can

be described using equilibrium curves

• For curves for transformers need the following

information:

– Concentration of water content in the dielectric liquid

in ppm with insulation temperature - prefer top oil

temp.

– Or direct measure of RS corrected to top oil

temperature

– Type of insulating liquid - mineral oil, silicone, ester...

n g o



Curves

• Moisture needs to be at a reasonable steady state

with the oil and solid insulation to use equilibrium

curves

– Adequately warm - the ideal is that the insulation has

been at 50C or warmer for at least 3 days with a

reasonably steady load or operating temperature

– Rapidly dropping temperatures over-estimates water

in paper as does use of equilibrium curves at low

temperatures

– 30 to 50C not reliable but provides “sense” of

dryness, above 50C good, above 60C excellent


37/68



Curves

• Families of equilibrium curves are provided for:

– Mineral oil in good condition

– Mineral oil with an acidity of minimum of 0.2

• If too high need to determine solubility characteristics

• Can use relative saturation measurement

– Silicone

– Midel 7131 synthetic ester

– Cooper Envirotemp FR3

– ABB Biotemp

– Dielectric Systems Eco Fluid (Eco-SYN)

e E n g i n e



Curves

• Families of equilibrium curves

– Assumes that the relative saturation of water in

dielectric liquid is equivalent to the equilibrium

relative humidity (vapor pressure/saturation vapor

pressure) at the same temperature

– Can be prepared for any dielectric where the water

solubility characteristics are known


38/68


Calculation for RS at Top Oil

Temperature

RS2=(RS1)(Sol1)/(Sol2)

RS2=Relative saturation at top oil temp.

RS1=Relative saturation at measured temp.

Sol1=Solubility of water in oil at measured temp.

Sol2=Solubility of water in oil at the top oil temp

i n g o m p


Change in RS between Measured

Bottom Oil and Top Oil Temperature, %

TempDifference, °C

Mineral OilT1=80°C

Mineral OilT1=40°C

AgedMineral OilT1=80°C

FR3T1=80°C

5 13

10 24 30 23 12

15 34

20 42 50 41 21

Aging of mineral oil not a factor but type of fluid is important

D o b l e

o m p


39/68


Equil ibrium Curves - Mineral Oil

Mineral Oi l - Paper Moisture Equilibrium Curve

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150

Water in oil Content (ppm)

W a t e r C o n t e n t i n P a p e r , %

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

105

110

115

120

a y


Equil ibrium Curves - Mineral OilMineral Oi l - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

0 10 20 30 40 50 60 70


W a t e r C o n

t e n t i n P a p e r , %

30

35

40

45

50

55

60

65

70

75

80

8590

95

100

105

110

115

120

D o b l

r n o

m a n


40/68


Equil ibrium Curves - Mineral Oil

Mineral Oi l - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150



30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

105

110

115

120

n o m

a n


Equil ibrium Curves - Mineral OilMineral Oi l - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

0 5 10 15 20 25 30


W a t e r C o n


30

35

40

45

50

55

60

65

70

75

80

8590

95

100

105

110

115

120

n e

n y


41/68


Equilibrium Curves - Aged Mineral Oil

Aged Mineral Oi l (acidity = 0.2 mg KOH/g) - Paper Moisture Equilibrium Curve

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

0 15 30 45 60 75 90 105 120 135 150 165 180 195 210 225 240

Water in Oil Content (ppm)


30

35

4045

50

55

60

65

70

75

80

85

90

95

100

105

110

115

120

o b l e E n g

i n e e r i n g

o m p a

n y


Equilibrium Curves - Aged Mineral Oil Aged Mineral Oi l (acidity = 0.2 mg KOH/g) - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150



30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

105

110

115

120

g o m

a n


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Equilibrium Curves - Aged Mineral Oil

Aged Mineral Oi l (acidity = 0.2 mg KOH/g) - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

0 15 30 45 60 75 90 105 120 135 150 165 180 195 210 225 240



30

35

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55

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65

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75

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85

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95

100

105

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120

e e


Equilibrium Curves - Aged Mineral Oil Aged Mineral Oi l (acidity = 0.2 mg KOH/g) - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

0 5 10 15 20 25 30 35 40 45 50



30

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n

o p n


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Equilibrium Curves - Silicone

Silicone - Paper Moisture Equilibrium Curve

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

0 50 100 150 200 250 300 350 400 450 500

Water in Silicone Content (ppm)


30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

105

110

115

120

D o b

r n


Equilibrium Curves - SiliconeSilicone - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

0 10 20 30 40 50 60 70 80 90 100 110 120



30

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o


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Equilibrium Curves - Silicone

Silicone - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

0 25 50 75 100 125 150 175 200 225 250 275 300



30

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95

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Equilibrium Curves - SiliconeSilicone - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

0 10 20 30 40 50 60 70



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o


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Equilibrium Curves - Midel 7131

Midel - Paper Moisture Equilibrium Curve

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

0 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000



30

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100

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120

r n


Equilibrium Curves - Midel 7131Midel - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

0 100 200 300 400 500 600 700 800 900 1000



30

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o

n


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Equilibrium Curves - Midel 7131

Midel - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

0 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000



30

35

40

45

50

55

60

65

70

75

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85

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95

100

105

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115

120

o b l e

o m


Equilibrium Curves - Midel 7131Midel - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

0 50 100 150 200 250 300 350 400 450 500



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65

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75

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p n


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Equilibrium Curves - Envirotemp FR3

Envirotemp FR3 - Paper Moisture Equilibrium Curve

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

0 150 300 450 600 750 900 1050 1200 1350 1500



30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

105

110

115

120

D o b l e E


Equilibrium Curves - Envirotemp FR3Envirotemp FR3 - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

0 50 100 150 200 250 300 350 400 450 500



30

35

40

45

50

55

60

65

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75

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95

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a n


48/68


Equilibrium Curves - Envirotemp FR3

Envirotemp FR3 - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

0 100 200 300 400 500 600 700 800 900 1000



30

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45

50

55

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o b l e E n g

i n e e r i n


Equilibrium Curves - Envirotemp FR3Envirotemp FR3 - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

0 25 50 75 100 125 150 175 200 225 250



30

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o


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Equilibrium Curves - Biotemp

Biotemp - Paper Moisture Equilibrium Curve

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

0 150 300 450 600 750 900 1050 1200 1350 1500



30

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40

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50

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D o b l e E

n


Equilibrium Curves - BiotempBiotemp - Paper Moisture Equilibrium Curve

0.00

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1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

0 50 100 150 200 250 300 350 400 450 500



30

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o


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Equilibrium Curves - Biotemp

Biotemp - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

0 100 200 300 400 500 600 700 800 900 1000



30

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40

45

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o b l e E n g

i n e e r i

n


Equilibrium Curves - BiotempBiotemp - Paper Moisture Equilibrium Curve

0.00

0.50

1.00

1.50

2.00

2.50

3.00

0 25 50 75 100 125 150 175 200 225 250



30

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o

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Equilibrium Curves - Eco Fluid

Eco fluid - Paper Moisture Equilibrium Curve

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

0 20 40 60 80 100 120 140 160 180 200



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D

e e r


Equilibrium Curves - Eco FluidEco Fluid - Paper Moisture Equilibrium Curve

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3.50

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0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75



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Equilibrium Curves - Eco Fluid

Eco Fluid - Paper Moisture Equilibrium Curve

0.00

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1.00

1.50

2.00

2.50

3.00

0 5 10 15 20 25



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o

e

p a n y


Equilibrium Curves - Eco FluidEco Fluid - Paper Moisture Equilibrium Curve

0.00

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1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

5.00

0 50 100 150 200 250 300 350 400 450 500



30

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r n g o

m p a n y


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Curves Using RS

• Can be used for all dielectric liquids

• Measure RS and record it along with temperature

of oil at measurement

• Correct to top oil temperature if measured at other

temperature

• Use moisture in paper vs RS - temperature curves

• Best means for estimating moisture in paper

n e e r i n

n y



Curves

• Calculation of relative saturation at various

temperatures with constant concentration

RS2 = RS1*SolT1/SolT2 where RS2 is the RS at the

desired temp., RS1 is at the measured temp, SolT1 is the

solubility at the measured temp and SolT2 is at the

desired temp.

0895.71567

K

S Log oSolubility in mineral oil

a n y


54/68


Equilibrium Curves Using RS

Dielectric Liquid - Paper Moisture Equilibrium Curve

0.00

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3.00

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5.00

6.00

7.00

8.00

9.00

10.00

0 5 10 15 20 25 30 35 40 45 50

Water in Oil Content (RS%)


30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

105

110

115

120

D o b l e E

n g i n e e r i

n o m

a


Equilibrium Curves Using RSDielectric Liquid - Paper Moisture Equilibrium Curve

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1.50

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4.50

5.00

5.50

6.00

6.50

7.00

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

2 0

2 1

2 2

2 3

2 4

2 5

2 6

2 7

2 8

2 9

3 0

Water in Oil Content (RS)

W a t e r C o n


30

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l e . E n g i n e e

r


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0.00

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3.50

4.00

4.50

5.00

0 5 10 15 20 25 30 35 40 45 50



30

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o b l e


Equilibrium Curves Using RSDielectric Liquid - Paper Moisture Equilibrium Curve

0.00

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2.50

3.00

3.50

4.00

4.50

5.00

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20



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o b l e


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0.00

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0 5 10 15 20



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120

o


Equilibrium Curves Using RSDielectric Liquid - Paper Moisture Equil ibrium Curve

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3.00

0 1 2 3 4 5 6 7 8 9 10



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Model to Estimate Water in Paper

• Measurements in learning period:

– Top/bottom oil temp. - if available

– Relative saturation – Estimate starting equilibrium conditions using specific

criteria and selected points

• Use change in temperature to redistribute moisture

between oil and paper

• Validate model and change in total water content in

transformer using measured water in oil content

• Begin use of transient model

n g o


Continuous Movement in a Transformer

Water Between Liquid Dielectric and Paper

0

2

4

6

8

10

12

14

1 5 9 1 3

1 7

2 1

2 5

2 9

3 3

3 7

4 1

4 5

4 9

5 3

5 7

6 1

6 5

6 9

7 3

7 7

8 1

8 5

8 9

9 3

9 7

1 0 1

1 0 5

1 0 9

1 1 3

1 1 7

1 2 1

1 2 5

1 2 9

1 3 3

1 3 7

Hours

R e l a t i v e S a t u r a t i o

n , % a n d W a t e r C o n t e n t , p p m

0

10

20

30

40

50

60

70

T em p er a t ur e ,D e gr e e s C

Relative Saturation

Water Content, ppm

Bottom Oil

l n e

r g o

n y


58/68


Changes in Water Content and %RS

0

2

4

6

8

10

12

1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96 101 106 111 116 121 126 131 136

RS%

PPM

DMPIface VALUE

DMP3 VALUE

DMP6 VALUEMPSS VALUE

Looks at moisture distribution over time. Takes into account

diffusion rates, temperature changes and physical characteristics

of the solid insulation

n g i

i n m p a

n


Moisture Distribution in Transformers

Oil Paper

Boundary Layers

Interface D b l e g

e r i n g

y o m p

a


59/68


Steady State and Transient Models

1

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2

1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96 101 106 111 116 121 126 131 136

DMPIface VALUE

DMP1 VALUE

DMP3 VALUE

DMP6 VALUE

MPSS VALUE

o b l e g

i n e e r i n g

m p a

y


Diffusion Time Water in Paper

o b l e E n

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60/68


Moisture Distribution

Location Temperature W ater in Oil

10 ppm

W ater in Oil

30 ppm

Bottom oilNon-Conductor

60 1.4 2.4

Bottom oil

Wrapped

conductor

75 0.9 1.6

Top oil

Non-conductor

75 0.9 1.6

Top oil

Wrapped

conductor

90 0.5 1.0

Hottest spot 98 0.4 0.7

l e E n i n

e e r i n g

a n y


Excessive Water in Oil

Cool down period of thermal transient

– Water migrates from paper oil with increasing

temp (due to load & ambient temp)

– At higher temp, moisture migration is quicker and

the solubility of water in oil is high

– During cool down, water remains mostly in the oiland for a long time…solubility also decreases

– Excessive water…High RS…low dielectric

breakdown voltage

– Condensation Possible

a n y


61/68


Excessive Water in Oil - Cool Down

Period of Thermal Transient

• These types of Transformers are most

susceptible

– Wetter transformers (> 1.5% in paper)

– Those that temperature cycle

– Those that temperature cycle quicker and to greater

extremes

– Operate at lower temperatures

p a n y


How to Make It Rain in a Transformer

D o e

n

E i e

r m p a

n y


62/68


Review of the Three Rules

OIL

CELLULOSE

OIOIL

1. Equilibration between

oil and paper based on

temperature.

3. As the temperature

increases, the water solubili ty in the oil also

increases.

2. Water moves f rom

paper to oil as the

temperature increases.

l e E n g i n

e r i n g


Relative Saturation at 3% (3/83 ppm)

30°C

HH

O

1.5% Water

2.5 ppm Water

D o b e E g i n e e

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63/68


Relative Saturation at 10% (70/678 ppm)

95°C

HH

O

1.5% Water

70 ppm Water

D o b l E

g i n e e

g n y

m p


Super Saturated (Condensation/

Rain)

0°C

HH

O

1.5% Water

70 ppm

Water

D o n g i n e e

g

y a o


64/68

Limits for Water in Transformers

D o b l e E

n g i n e e r i

n


Doble Recommended Limits for

Moisture-In-Oil Results

• Below 30C Top Oil

• Between 30 and 50C Top Oil

• Greater than 50C Top Oil

D o b l

e e r i n

o m p a n y


65/68


Below 30°C Top Oil

• Use Concentration Limits

• %RS


66/68


Between 30 and 50°C Top Oil Temp.

• Begin to look at %RS closer - note that it is

dependent on operating temperature trends

• Equilibrium curves can still be misleading

5% RS Excellent

5 to 10% RS Good

11 to 20% RS Okay – possibly wet

21 to 30% RS Wet

>30% RS Extremely Wet80

n g i n e e

r i o m p


Greater Than 50°C

• Concentration rules no longer useful

• Look at %RS and equilibrium curves

5% RS Excellent

5 to 10% RS Good – Okay

11 to 20% RS Probably Wet

>20% RS Wet80

When the RS is consistently greater than 5% use

equilibrium curves to estimate moisture in paper

o E n g i n e e

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67/68


Use of Curves to Estimate Water Content

in Paper Above 50°C

3.5% water in paper Very Wet80

*Tolerance depends on application and expected

operating environment

D o

g n y


Excessive Water in Oil

Cool down period of thermal transient

– Water migrates from paper oil with increasing temp (due

to load & ambient temp)

– At higher temp, moisture migration is quicker and the

solubility of water in oil is high

– During cool down, water remains mostly in the oil and for

a long time…solubility also decreases

– Excessive water…High RS…low dielectric breakdown

voltage

– Condensation Possible

o

g o


68/68


Limits Based on Cold

Temperature Operation

ColdestOperatingTemp, C

50% RS,Conc. inppm

HottestTop OilTemp, C

Equil.Water inOil at

1.0%water inpaper


2.0%water inpaper


3.0%water inpaper

20 28 100 43 123 225

0 11.5 80 18 52 95

-20 4.0 60 7 20 37

-40 1.2 40 2.5 6.9 13

o b l g

i n e e

.

y

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