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Transcript of 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.
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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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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 in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Leak through Bushing
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Trapped Water - Core Steel
DRY
WET (white bumps arewater droplets being
charged by the SEM)
o
p
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Tank Steel
Unpainted Painted
g
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
States of Water
Free Water
Dissolved Water Emulsified Water
i
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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 in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Sampling of Dielectric Liquidsfor Water Content
D o b l e E
n g i n e e r
o m p
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Containers
Plastic - there are
no acceptable plastic
containers
D o b l e E n g i n e e
r i
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Preferred Container - Glass Syringes
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Acceptable Bottles - Glass and Metal
n e e
r i
n g
g p a n
y
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Adapter
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Approx. 1.45 quarts to
reach equilibrium
Approx. 0.78 quarts to
reach equilibriumvs.
n g i e
r i n o
m p a n
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
2.01% water in paper
2.62% water in paper
D o b l e E
n g i n e e r i
n g o
y
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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Importance of Water inTransformers
D o b l e E
n g i n e e r i
n g o m p
y
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Bubble Evolution
Primarily Influenced by Water Content of Paper
Emergency Loading to Hot-Spot Temperature
Operate Below Water in Paper Content
180C
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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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 in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
%
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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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Water in Transformers - Equilibrium
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Water in Transformers - Equilibrium
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Water in Transformers - Equilibrium
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
8590
95
100
105
110
115
120
D o b l
r n o
m a n
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
n o m
a n
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
8590
95
100
105
110
115
120
n e
n y
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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)
W a t e r C o n t e n t i n P a p e r , %
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
g o m
a n
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
e e
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
n
o p n
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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)
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
D o b
r n
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Silicone 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
o
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Silicone 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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
Water in Silicone 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
o
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
r n
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
o
n
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
o b l e
o m
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
p n
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
D o b l e E
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
o b l e E n g i n e e
a n
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
o b l e E n g
i n e e r i n
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
o
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
D o b l e E
n
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Equilibrium Curves - BiotempBiotemp - 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
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
o
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
o b l e E n g
i n e e r i
n
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
o
n
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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
D
e e r
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Equilibrium Curves - Eco FluidEco Fluid - 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 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Equilibrium Curves - Eco Fluid
Eco Fluid - Paper Moisture Equilibrium Curve
0.00
0.50
1.00
1.50
2.00
2.50
3.00
0 5 10 15 20 25
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
o
e
p a n y
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Equilibrium Curves - Eco FluidEco Fluid - 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
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
o b l e E n g i n e e
r n g o
m p a n y
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Water in Transformers - Equilibrium
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
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Water in Transformers - Equilibrium
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
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Equilibrium Curves Using RS
Dielectric Liquid - 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 5 10 15 20 25 30 35 40 45 50
Water in Oil Content (RS%)
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
D o b l e E
n g i n e e r i
n o m
a
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Equilibrium Curves Using RSDielectric Liquid - 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
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
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
l e . E n g i n e e
r
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Equilibrium Curves Using RS
Dielectric Liquid - 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 5 10 15 20 25 30 35 40 45 50
Water in Oil Content (RS)
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Equilibrium Curves Using RSDielectric Liquid - 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 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Water in Oil Content (RS)
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Equilibrium Curves Using RS
Dielectric Liquid - Paper Moisture Equilibrium Curve
0.00
0.50
1.00
1.50
2.00
2.50
3.00
0 5 10 15 20
Water in Oil Content (RS)
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
o
Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Equilibrium Curves Using RSDielectric Liquid - Paper Moisture Equil ibrium Curve
0.00
0.50
1.00
1.50
2.00
2.50
3.00
0 1 2 3 4 5 6 7 8 9 10
Water in Oil Content (RS)
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Moisture Distribution in Transformers
Oil Paper
Boundary Layers
Interface D b l e g
e r i n g
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Diffusion Time Water in Paper
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
How to Make It Rain in a Transformer
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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.
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Relative Saturation at 10% (70/678 ppm)
95°C
HH
O
1.5% Water
70 ppm Water
D o b l E
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Super Saturated (Condensation/
Rain)
0°C
HH
O
1.5% Water
70 ppm
Water
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Limits for Water in Transformers
D o b l e E
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Doble Recommended Limits for
Moisture-In-Oil Results
• Below 30C Top Oil
• Between 30 and 50C Top Oil
• Greater than 50C Top Oil
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Below 30°C Top Oil
• Use Concentration Limits
• %RS
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
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
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Water in Electric Apparatus - Doble Insulating Materials Tutorial Oct. 2009
Limits Based on Cold
Temperature Operation
ColdestOperatingTemp, C
50% RS,Conc. inppm
HottestTop OilTemp, C
Equil.Water inOil at
1.0%water inpaper
Equil.Water inOil at
2.0%water inpaper
Equil.Water inOil at
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
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