Envirotemp ® FR3 ® Fluid - Waukesha Electric

Envirotemp ® FR3 ® Fluid
6 June 2007
Cooper Power Systems Cooper Power Systems
McGraw-Edison Development Corporation 1900 East North Street
19, Mykinon Street Waukesha, Wisconsin 53188-3899
GR-166 74 Glyfada, Athens USA
GREECE
telephone: +30 210 964 6332 telephone: +01 262 524 3300
email: cps-athens@cooperpower.com
®

Contents
1. Dielectric properties
1.1. Partial discharge behavior .................................................................................................... 4
1.2. Withstand capability curves .................................................................................................. 5
1.3. Effect of dissolved water and temperature on dielectric strength ......................................... 7
1.4. Effect of voltage distribution in insulation structure ............................................................... 8
1.5. Effect of temperature on power factor and dielectric constant ............................................. 8
1.6. Creep withstand .................................................................................................................. 10
2. Thermal properties
2.1. Viscosity at low temperatures ............................................................................................. 11
3. Ageing
3.1. Oxidation inhibitors .............................................................................................................. 11
3.2. Transport atmosphere ......................................................................................................... 11
3.3. Long term ageing fluid properties ....................................................................................... 12
3.4. Impact of moisture and dissolved oxygen on ageing .......................................................... 15
3.5. Dissolved oxygen ................................................................................................................ 15
3.6. Causes of dissolved gas ..................................................................................................... 15
3.7. Typical dissolved gas spectra ............................................................................................. 15
3.8. Dissolved gas and ageing ................................................................................................... 16
3.9. Sensitivity to oxygen of immersed material in air ................................................................ 17
3.10. Normal gassing ................................................................................................................... 18
3.11. Effectiveness of gas extraction ........................................................................................... 19
3.12. Interpretation of dissolved gas data .................................................................................... 19
4. General properties
4.1. Fluid preservation ................................................................................................................ 19
4.2. Materials compatibility ......................................................................................................... 19
4.3. Water absorption during maintenance and on-site drying .................................................. 20
4.4. Measures to avoid polymerization ...................................................................................... 20
4.5. Traces of other liquids ......................................................................................................... 20
4.6. Aging rate of thermal upgraded paper ................................................................................ 21
4.7. Electrostatic charging and streaming electrification ............................................................ 22
5. Handling / oil processing
2
5.1. Processing rigs .................................................................................................................... 22
5.2. Impregnating solid insulation .............................................................................................. 22
5.3. Influence of other oils and synthetic liquids during degassing ............................................ 22
5.4. Disposal methods ................................................................................................................ 22
5.5. Hydrolytic stability ............................................................................................................... 22

5.6. Processing for water content .............................................................................................. 22
5.7. Vapor phase processing ..................................................................................................... 22
References .......................................................................................................................................... 22
3

1. Dielectric properties
Partial Discharge Inception (kV)
4
1.1 Partial discharge behavior
Envirotemp FR3 fluid appears to have a higher partial discharge inception voltage compared to
mineral oil.
40
30
20
10
Figure 1 shows results obtained by the
University of New South Wales using
needle to spherical section geometry [1].
Water was added to the fluids for the 4
mm gap tests, resulting in a much smaller
inception voltage for both fluids.
The breakdown voltages of the two fluids
are quite different, however. Envirotemp
FR3 fluid has a much higher breakdown
voltage compared to mineral oil. This may
be attributed to its higher tolerance of
water.
Figures 2-4 show results from the
University of Hannover [2] using the
IEC 61294 method and a 50mm gap.
The variations of partial discharge
inception with regard to temperature
and relative water content were
explored. At low relative saturations,
mineral oil and Envirotemp FR3 fluid
have similar inception voltages. As the
relative water contents increase,
Envirotemp FR3 fluid appears to have
higher inception voltages compared to
mineral oil.
IEC 61294, needle-plane, 50mm gap, University of Hanover
Envirotemp FR3 fluid (50 o C)
mineral oil (60 o C)
0
0 5 10 15 20 25 30 35
Water Content as Relative Saturation (%)
Figure 3. Partial discharge inception voltage versus
water content of mineral oil at 60°C and Envirotemp
FR3 fluid at 50°C. [2]
Voltage (kV)
20
15
10
5
0
transformer oil Envirotemp FR3 fluid
inception breakdown inception breakdown inception breakdown
2 mm gap 3 mm gap 4 mm gap + H2O
Partial Discharge (point - semisphere)
Figure 1. Partial discharge inception voltage for
mineral oil and Envirotemp FR3 fluid. [1]
Partial Discharge Inception (kV)
Partial Discharge Inception (kV)
40
30
20
10
Envirotemp FR3 fluid: needle-plane
Envirotemp FR3 fluid: needle-sphere
IEC 61294, 50mm gap, University of Hanover
mineral oil: needle-plane
mineral oil: needle-sphere
0
0 20 40 60 80
Water Content as Relative Saturation at 20 o C (%)
Figure 2. Partial discharge inception voltage versus
water content of mineral oil and Envirotemp FR3
fluid at 20°C. [2]
40
30
20
10
IEC 61294, needle-plane, 50mm gap, University of Hanover
Envirotemp FR3 fluid
mineral oil
0
0 2 4 6 8 10 12 14 16 18 20
Water Content as Relative Saturation at 90 o C (%)
Figure 4. Partial discharge inception voltage versus
water content of mineral oil and Envirotemp FR3 fluid
at 90°C. [2]

1.2 Withstand capability curves
Oil gap withstand tests were conducted at three laboratories according to their voltage
capabilities: Cooper Power Systems, Doble Engineering, and Waukesha Electric Systems. Figure
5 shows the electrode configurations. Withstand capabilities for 60 Hz (Figure 6), full wave
negative and positive impulse (Figure 7), chopped wave negative and positive impulse (Figure 8),
and switching surge negative and positive impulse (Figure 9) are shown.
Sphere-to-sphere full wave negative impulse withstand is shown in Figure 10. The University of
Manchester used the ASTM D3300 test method with a 12.7mm gap.
All of the results demonstrate that the oil gap withstand capabilities of mineral oil and Envirotemp
FR3 fluid are, for all practical purposes, equivalent.
(a) (b) (c)
Figure 5. Electrode configurations for oil gap tests performed at the Thomas A. Edison Technical Center (a), Doble
Engineering (b), and Waukesha Electric Systems (c).
60 Hz Breakdown (kV/mm)
100
10
Doble
Engineering
Waukesha
Electric Systems
Thomas A. Edison
Technical Center
mineral oil
Envirotemp FR3 fluid
mineral oil
Envirotemp FR3 fluid
mineral oil
Envirotemp FR3 fluid
1
1 10 100
Oil Gap (mm)
Figure 6. AC withstand for mineral oil and Envirotemp
FR3 fluid.
Full Wave Negative Impulse (kV/mm)
Full Wave Positive Impulse (kV/mm)
100
10
Doble
Engineering
Waukesha
Electric Systems
Thomas A. Edison
Technical Center
mineral oil
Envirotemp FR3 fluid
mineral oil
Envirotemp FR3 fluid
mineral oil
Envirotemp FR3 fluid
1
1 10 100
100
10
Doble
Engineering
Waukesha
Electric Systems
Thomas A. Edison
Technical Center
Oil Gap (mm)
(a)
mineral oil
Envirotemp FR3 fluid
mineral oil
Envirotemp FR3 fluid
mineral oil
Envirotemp FR3 fluid
1
1 10 100
Oil Gap (mm)
Figure 7. Negative (a) and positive (b) full wave
impulse withstand for mineral oil and Envirotemp FR3
fluid.
(b)
5

Chopped Wave Negative Impulse (kV/mm)
Chopped Wave Positive Impulse (kV/mm)
100
10
Doble
Engineering
Thomas A. Edison
Technical Center
mineral oil
Envirotemp FR3 fluid
mineral oil
Envirotemp FR3 fluid
1
1 10 100
Oil Gap (mm)
Figure 8. Chopped wave negative (a) and positive (b)
impulse withstand for mineral oil and Envirotemp FR3
fluid.
Full Wave Negative Impulse (kV/mm)
100
20
15
10
5
0
10
Doble
Engineering
Thomas A. Edison
Technical Center
(a)
mineral oil
Envirotemp FR3 fluid
mineral oil
Envirotemp FR3 fluid
1
1 10 100
Oil Gap (mm)
(b)
ASTM D3300, sphere-sphere, 12.7mm gap, University of Manchester
Absolute Water Content (mg/kg)
mineral oil
Envirotemp FR3 fluid
0 100 200 300 400
Switching Surge Negative Impulse (kV/mm)
Switching Surge Positive Impulse (kV/mm)
100
10
Doble
Engineering
Waukesha
Electric Systems
Thomas A. Edison
Technical Center
mineral oil
Envirotemp FR3 fluid
mineral oil
Envirotemp FR3 fluid
mineral oil
Envirotemp FR3 fluid
1
1 10 100
100
10
Doble
Engineering
Waukesha
Electric Systems
Thomas A. Edison
Technical Center
Oil Gap (mm)
(a)
mineral oil
Envirotemp FR3 fluid
mineral oil
Envirotemp FR3 fluid
mineral oil
Envirotemp FR3 fluid
1
1 10 100
Oil Gap (mm)
(b)
Figure 9. Switching surge negative (a) and positive (b)
impulse withstand for mineral oil and Envirotemp FR3
fluid.
0
0 10 20 30 40
Relative Water Content (% 20 o C saturation)
(a) (b)
Figure 10. Full wave negative impulse strength versus absolute water content (a) and relative water content (b) of
mineral oil and Envirotemp FR3 fluid. [2]
6
Full Wave Negative Impulse (kV/mm)
20
15
10
5
ASTM D3300, sphere-sphere, 12.7mm gap, University of Manchester
mineral oil
Envirotemp FR3 fluid

D1816 Dielectric Breakdown Strength (kV)
D1816 Dielectric Breakdown Strength (kV)
1.3 Effect of dissolved water and temperature on dielectric strength
The dependence of dielectric breakdown strength on water content is shown in Figures 11-13.
Variation of ASTM D1816 (VDE electrodes) dielectric breakdown strength in term of both absolute
and relative water contents are shown for 2mm gap (Figure 11) and 1mm gap (Figure 12). The
ASTM D877 (disk electrodes) dependence on absolute water content is shown in Figure 13.
80
70
60
50
40
30
20
10
Dielectric breakdown strength variation with temperature is given in Figure 14.
0
0 100 200 300 400 500 600 700
Water Content (mg/kg)
(a)
(b)
Envirotemp FR3 fluid
mineral oil
Figure 11. Dielectric breakdown strength versus water
content for mineral oil and Envirotemp FR3 fluid.
D 877 Dielectric Breakdown (kV)
80
70
60
50
40
30
20
10
0
0 20 40 60 80 100 120 140 160 180 200
80
70
60
50
40
30
20
10
Water Content (% of 20 o C saturation)
Water Content (ppm)
Envirotemp FR3 fluid
mineral oil
Envirotemp FR3 fluid
FR3 production history
conventional transformer oil
0
0 100 200 300 400 500 600
Figure 13. Dielectric breakdown strength versus water
content for mineral oil and Envirotemp FR3 fluid.
Dielectric Breakdown Strength (kV)
Dielectric Breakdown Strength (kV)
50
40
30
20
10
0
50
40
30
20
10
ASTM D1816, 1mm gap, University of Manchester
0 100 200 300 400
Absolute Water Content (mg/kg)
mineral oil
Envirotemp FR3 fluid
(a)
(b)
mineral oil
Envirotemp FR3 fluid
ASTM D1816, 1mm gap, University of Manchester
0
0 10 20 30 40
Relative Water Content (% 20 o C saturation)
Figure 12. Dielectric breakdown strength versus water
content for mineral oil and Envirotemp FR3 fluid. [3]
D1816 Dielectric Breakdown Strength (kV)
100
80
60
40
20
0
-40 -20 0 20 40 60
Temperature ( o C)
mineral oil
Envirotemp FR3 fluid
Figure 14. Dielectric breakdown strength versus
temperature for mineral oil and Envirotemp FR3 fluid.
7

Relative Permittivity
8
1.4 Effect of voltage distribution in insulation structure
“The dielectric strength of solid insulation (in this case Kraft insulation impregnated with dielectric
fluid) is close to an order of magnitude higher than the fluid itself. Thus the weak material in the
insulation structure is the fluid. By bringing the permittivity of the liquid and solid insulation closer
together more of the dielectric stress will be distributed in the solid material. This will reduce the
stress in the fluid, which typically sets the design clearance.” T. Prevost, presentation of [4]
An example is given in Figure
28.
ε1=permittivity fluid
mineral oil ≅ 2 FR3 fluid ≅ 3
ε2=permittivity solid insulation
solid insulation ≅ 4
Z=(d1/ε1) + (d2/ε2)
Let d1 = d2 = 5mm
E1= U/(ε1 * Z)
E2= U/(ε2 * Z)
U= Applied Voltage
Let U = 100 kV
E1= Stress fluid
E2= Stress in solid insulation
Mineral oil:
E1= 13.33 kV/mm
E2= 6.67 kV/mm
Envirotemp FR3 fluid:
E1= 11.43 kV/mm
E2= 8.57 kV/mm
Figure 28. Dielectric breakdown strength versus temperature for mineral
oil and Envirotemp FR3 fluid. from T.A. Prevost presentation of [4]
1.5 Effect of temperature on power factor and dielectric constant
The dielectric constants of mineral oil and Envirotemp FR3 fluid as a function of temperature are
shown in Figure 14. The University of Hannover [2] values are the average dielectric constant for
a range of water contents. The error bars represent the maximum and minimum dielectric
constants. Envirotemp FR3 fluid was tested at water contents of 30, 50, 200, and 500 mg/kg;
mineral oil was tested at 11, 20, and 40 mg/kg. Figures 15-17 show the dielectric constants of
impregnated solid insulation versus temperature.
4.0
3.5
3.0
2.5
2.0
1.5
EHV Weidmann Thomas A. Edison Technical Center University of Hannover
mineral oil mineral oil
mineral oil
FR3 fluid FR3 fluid
-20 0 20 40 60 80 100 120
Temperature ( o C)
FR3 fluid
Figure 14. Relative permittivity versus temperature of
mineral oil and Envirotemp FR3 fluid.
Diamond Pattern Paper
Relative Permittivity
5.5
5.0
4.5
4.0
3.5
20 40 60 80 100 120
Temperature ( o C)
mineral oil
Envirotemp FR3 fluid
Figure 15. Relative permittivity versus temperature of
Kraft paper impregnated with mineral oil and
Envirotemp FR3 fluid.

Medium Density Pressboard
Relative Permittivity
Dielectric Fluid
Dissipation Factor (%)
Medium Density Pressboard
Dissipation Factor (%)
5.5
5.0
4.5
4.0
mineral oil
Envirotemp FR3 fluid
3.5
20 40 60 80 100 120
Temperature ( o C)
Figure 16. Relative permittivity versus temperature of
T-IV pressboard impregnated with mineral oil and
Envirotemp FR3 fluid.
10
1
0.1
0.01
0.001
High Density Pressboard
Relative Permittivity
5.5
5.0
4.5
4.0
3.5
20 40 60 80 100 120
Temperature ( o C)
mineral oil
Envirotemp FR3 fluid
Figure 17. Relative permittivity versus temperature of
Hi-Val pressboard impregnated with mineral oil and
Envirotemp FR3 fluid.
Dissipation factors of mineral oil and Envirotemp FR3 fluid as a function of temperature are shown
in Figure 18. Again, the University of Hannover [2] values are the average dielectric constant for a
range of water contents, and the error bars represent the maximum and minimum values. Figures
19-21 show the dissipation factors of impregnated solid insulation versus temperature.
University of Hannover
mineral oil
FR3 fluid
EHV Weidmann
mineral oil
FR3 fluid
0 20 40 60 80 100 120
Temperature ( o C)
Thomas A. Edison Technical Center
mineral oil
FR3 fluid
Figure 18. Dissipation factor versus temperature of
mineral oil and Envirotemp FR3 fluid.
10
1
0.1
0.01
Temperature ( o C)
mineral oil
Envirotemp FR3 fluid
0.001
20 40 60 80 100 120
Figure 20. Dissipation factor versus temperature of T-IV
pressboard impregnated with mineral oil and
Envirotemp FR3 fluid.
Diamond Pattern Paper
Dissipation Factor (%)
10
1
0.1
0.01
0.001
20 40 60 80 100 120
Temperature ( o C)
mineral oil
Envirotemp FR3 fluid
Figure 19. Dissipation factor versus temperature of
Kraft paper impregnated with mineral oil and
Envirotemp FR3 fluid.
High Density Pressboard
Dissipation Factor (%)
10
1
0.1
0.01
0.001
20 40 60 80 100 120
Temperature ( o C)
mineral oil
Envirotemp FR3 fluid
Figure 21. Dissipation factor versus temperature of
Hi-Val pressboard impregnated with mineral oil and
Envirotemp FR3 fluid.
9

60 Hz Creep Breakdown Stress (kV/mm)
60 Hz Creep Breakdown Stress
Weibull 1% Probability (kV/mm)
10
1.6 Creep Withstand Capabilities
AC and impulse creep withstand tests were performed by EHV Weidmann [4]. Their electrode
configuration is shown in Figure 27. The geometry gives a non-uniform field with the highest
stress along the pressboard-fluid interface. The electrode and test specimen are designed to
minimize the effect of oil wedges.
100
10
(a) (b)
Figure 27. EHV Weidmann creep electrode design (a) and photo of creep
breakdown (b). [4]
1
1 10 100
100
10
EHV Weidmann
mineral oil
Envirotemp FR3 fluid
EHV Weidmann
Envirotemp FR3 fluid
mineral oil
Creep Distance (mm)
(a)
Weidmann design curve
1
1 10 100
Creep Distance (mm)
(b)
Figure 22. 60 Hz creep strength of mineral oil and
Envirotemp FR3 fluid: (a) shows test values and (b)
shows the calculated Weibull 1% probability.
Full Wave Negative Creep
Breakdown Stress (kV/mm)
Full Wave Negative Creep
Weibull 1% Probability (kV/mm)
100
10
EHV Weidmann
mineral oil
Envirotemp FR3 fluid
1
1 10 100
100
10
EHV Weidmann
Envirotemp FR3 fluid
mineral oil
Weidmann design curve
Creep Distance (mm)
(a)
1
1 10 100
Creep Distance (mm)
(b)
Figure 23. Full wave negative creep strength of
mineral oil and Envirotemp FR3 fluid: (a) shows test
values and (b) shows the calculated Weibull 1%
probability.

Full Wave Positive Creep
Breakdown Stress ( kV/mm)
100
10
For AC creep withstand (Figure 22) and negative full wave impulse creep withstand (Figure 23),
the Weibull 1% probability is calculated and compared to the published Weidmann creep curve.
Figure 24 shows the results to date for positive full wave impulse creep withstand. Tests
completed to date demonstrate that the creep strengths of mineral oil and Envirotemp FR3 fluid
are, for all practical purposes, equivalent.
EHV Weidmann
mineral oil
Envirotemp FR3 fluid
1
1 10 100
Creep Distance (mm)
Figure 24. Full wave positive impulse creep withstand
of mineral oil and Envirotemp FR3 fluid
2. Thermal properties
1000
100
10
Kinematic Viscosity (cSt) 10000
2
Envirotemp FR3 fluid
7-day hold
conventional transformer oil
-20 0 20 40 60 80 100 120 140
Temperature ( o C)
Figure 25. Viscosity versus temperature for mineral oil
and Envirotemp FR3 fluid
2.1 Viscosity at low temperatures
Many variables affect the low temperature flow characteristics of Envirotemp FR3 fluid. The low
temperature viscosity depends not only on the temperature, but also time at temperature, the rate
of cooling, and the fluid volume. Figure 25 shows the viscosity versus temperature curves for
mineral oil and Envirotemp FR3 fluid. Comparing the 7-day hold values to the standard viscosity
shows the time at temperature effect.
3. Ageing
(Another Cooper Power Systems’ product, R-Temp fluid, has a pour point similar to that of
Envirotemp FR3 fluid, but its viscosity is considerably higher. R-Temp fluid had the same cold flow
concerns, but has had no field issues in 30+ years of cold climate applications.)
3.1 Oxidation inhibitors
Envirotemp FR3 fluid contains an additive package that includes a proprietary oxidation inhibitor
at 0.4 wt%. The ASTM D4768 gas chromatography method for determining the inhibitor content in
insulating liquids can be used to determine the inhibitor content in Envirotemp FR3 fluid.
3.2 Transport atmosphere
Tests using transformer power factor
models are currently underway to evaluate
the effects of dry air transport of
transformers using Envirotemp FR3 fluid.
The pressboard models, impregnated with
mineral oil and Envirotemp FR3 fluid,
emulate the geometry of power transformer
coils on a small scale (Figure 26).
Figure 26. Example of power factor model used in
tests to evaluate dry air transport of Envirotemp FR3
11

D1816 Dielectric Strength, 2mm gap (kV)
DC Resistivity (Ω-cm)
12
3.3 Long term ageing fluid properties
A number of side-by-side accelerated aging tests have been conducted using Envirotemp FR3
fluid and mineral oil. One series of tests used transformer construction materials in the proper
proportions to evaluate material compatibility. The tests, run at multiple temperatures and times,
show the changes in fluid properties over 4 IEEE “normal” lifetimes, the rough equivalent of 86
years of operation at rated load (Figures 27-34).
80
70
60
50
40
30
20
10
Envirotemp
FR3 fluid
130 o C
150 o C
170 o C
0
0 1 2 3 4
Equivalent "Normal" Lifetimes
mineral
oil
130 o C
150 o C
170 o C
Figure 27. Dielectric breakdown strength versus time
for mineral oil and Envirotemp FR3 fluid.
1e+16
1e+15
1e+14
1e+13
1e+12
Envirotemp
FR3 fluid
130 o C
150 o C
170 o C
1e+11
0 1 2 3 4
Equivalent Lifetimes
mineral
oil
130 o C
150 o C
170 o C
Figure 29. Resistivity versus time for mineral oil and
Envirotemp FR3 fluid.
Dissipation Factor, 25 o C (%)
10
1
0.1
0.01
0.001
Envirotemp
FR3 fluid
130 o C
150 o C
170 o C
0 1 2 3 4
Equivalent "Normal" Lifetimes
mineral
oil
130 o C
150 o C
170 o C
Figure 28. Dissipation factor versus temperature for
mineral oil and Envirotemp FR3 fluid.
Acid Number (mg KOH/g)
10
1
0.1
0.01
Envirotemp
FR3 fluid
0.001
0 1 2 3 4
Equivalent "Normal" Lifetimes
130 mineral
oil
o C
130 o C
150 o C 150 o C
170 o C 170 o C
Figure 30. Acid number versus temperature for
mineral oil and Envirotemp FR3 fluid.
Interfacial Tension (dyne/cm)
50
40
30
20
10
Envirotemp
FR3 fluid
0
0 1 2 3 4
Equivalent "Normal" Lifetimes
130 mineral
oil
o C 130 o C
150 o C 150 o C
170 o C 170 o C
Figure 31. Interfacial tension versus time for mineral
oil and Envirotemp FR3 fluid.

Water Content (mg/kg)
Water Content (% 25 o C saturation)
Fire Point (oC)
100
80
60
40
20
Envirotemp
FR3 fluid
0
0 1 2 3 4
100
80
60
40
20
Equivalent "Normal" Lifetimes
Envirotemp
FR3 fluid
(a)
Equivalent "Normal" Lifetimes
130 mineral
oil
o C 130 o C
150 o C 150 o C
170 o C 170 o C
130 mineral
oil
o C 130 o C
150 o C 150 o C
170 o C 170 o C
0
0 1 2 3 4
(b)
Figure 32. Water content versus time as (a) absolute
water content and (b) relative water content of mineral
oil and Envirotemp FR3 fluid.
360
350
340
330
180
170
160
Envirotemp
FR3 fluid
Equivalent "Normal" Lifetimes
130 mineral
oil
o C 130 o 150
C
o C
150 o C
170 o C
170 o C
150
0 1 2 3 4
Viscosity at 100 o C (mm 2 /s)
Viscosity at 40 o C (mm 2 /s)
10
8
6
4
2
Envirotemp
FR3 fluid
130 o C
150 o C
170 o C
0
0 1 2 3 4
50
40
30
20
10
Equivalent "Normal" Lifetimes
Envirotemp
FR3 fluid
(a)
130 o C
150 o C
170 o C
Equivalent "Normal" Lifetimes
mineral
oil
mineral
oil
130 o C
150 o C
170 o C
130 o C
150 o C
170 o C
0
0 1 2 3 4
(b)
Figure 33. Kinematic viscosity versus time at (a)
100°C and (b) 40°C of mineral oil and Envirotemp
FR3 fluid.
Flash Point ( o C)
340
320
300
280
170
160
150
Envirotemp
FR3 fluid
0 1 2 3 4
Equivalent Lifetimes
(a) (b)
Figure 34. Flash point (a) and fire point (b) versus time of mineral oil and Envirotemp FR3 fluid.
130 o C
130 o 150
C
o C
150 o C
170 o C 170 o mineral
oil
C
13

Temperature ( o C)
Dielectric Breakdown Voltage (kV)
14
360
340
320
300
Figure 35 shows the dielectric breakdown
strength versus dissipation factor at 25°C
for Envirotemp FR3 fluid. The fairly small
decrease in dielectric strength indicates the
high dissipation factor is due to larger polar
molecules resulting from Envirotemp FR3
fluid thermal degradation instead of
conductive particulate contaminants.
D1816 Dielectric Breakdown Strength (kV)
100
80
60
40
20
110 o C
150 o C
130 o C 170 o C
210 o C (Nomex)
10-3 10-2 10-1 100 101 102 0
Dissipation Factor, 25 o C (%)
Figure 35. Dielectric breakdown strength versus
dissipation factor Envirotemp FR3 fluid 2mm gap.
The transformers having the longest continuous service are installed at a Cooper Power Systems
factory in Waukesha, Wisconsin. These transformers, both 225 kVA 3P and installed in 1996,
have been constantly loaded at about 90% of nameplate rating and periodically monitored. The
fluid properties are shown in Figures 36-42. Several laboratories have tested the fluid samples
over the years, accounting for some of the variations seen. Except for resistivity (Figure 40), which
shows a moderate decrease over time, the properties remain essentially unchanged. Of note is
the viscosity (Figure 37). Viscosity is the definitive indicator of oxidation in Envirotemp FR3 fluid.
The unchanging viscosity demonstrates absence of fluid oxidation in the transformers.
Fire Point:
Flash Point:
IEC 61203 continued service fire point minimum
ASTM D6871 new fluid fire point minimum
S/N 1429 S/N 1430
S/N 1429 S/N 1430
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
Figure 36. Flash and fire points over time of new
transformers filled with Envirotemp FR3 fluid.
100
80
60
40
20
S/N 1429: S/N 1430:
D1816, 2mm gap D1816, 2mm gap
D877
D877
0
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
Figure 38. Dielectric breakdown strength over time of
new transformers filled with Envirotemp FR3 fluid.
Kinematic Viscosity (cSt)
Dissipation Factor at 25 o C (%)
50
40
30
20
10
ASTM D6871 40 o C new fluid maximum
40 o C:
100 o C:
ASTM D6871 100 o C new fluid maximum
S/N 1429 S/N 1430
S/N 1429 S/N 1430
0
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
Figure 37. Kinematic viscosity over time of new
transformers filled with Envirotemp FR3 fluid.
0.8
0.6
0.4
0.2
ASTM D6871 new fluid maximum
IEC 1203 continued service maximum (60 Hz)
S/N 1429
S/N 1430
0.0
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
Figure 39. Dissipation factor over time for new
transformers filled with Envirotemp FR3 fluid.

DC Resisitvity (ohm-cm)
1e+15
1e+14
1e+13
1e+12
(IEC 61203 continued service minimum)
S/N 1429
S/N 1430
1e+11
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
Figure 40. Resistivity over time of new transformers
filled with Envirotemp FR3 fluid.
Interfacial Tension (dyne/cm)
50
40
30
20
S/N 1429
S/N 1430
10
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
Figure 42. Interfacial tension over time of new
transformers filled with Envirotemp FR3 fluid.
Acid Number (mg KOH/g)
10
1
0.1
IEC 61203 continued service maximum
ASTM D6871 new fluid maximum
S/N 1429
S/N 1430
0.01
1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006
Figure 41. Acid number over time of new transformers
filled with Envirotemp FR3 fluid.
Water Content in Paper (wt%)
6
5
4
3
2
1
540
672
824
0 o C
10 o C
996
20 o C
30 o C
1189
Solubility Limit (mg/kg)
40 o C
50 o C
1403
70 o C
60 o C
90 o C
0
0 200 400 600 800 1000
1640
1898
80 o C
Water Content in Envirotemp FR3 Fluid (mg/kg)
110 o C
100 o C
2179
2481
2806
3151
3519
Figure 43. Water content in Envirotemp FR3 fluid in
equilibrium with water content in thermally upgraded
Kraft paper based on vapor pressure of water (“Piper”
chart).
3.4 Impact of moisture and dissolved oxygen on ageing
Increasing water content in the solid insulation increases its aging rate (thermo-hydrolytic
degradation). The solubility of water in Envirotemp FR3 fluid is higher than that of mineral oil,
shifting the equilibrium and causing water to migrate from the paper into the fluid. Figure 43 shows
the effect of the equilibrium shift and its drying effect on the solid insulation. The influence of the
water shift is discussed in [10,11].
3.5 Dissolved oxygen
Dissolved oxygen in and of itself is not a problem. The amount of oxygen that can be dissolved
into Envirotemp FR3 from the headspace or as a result of small leaks is insignificant in terms of
fluid stability. The concern instead is long-term (years) free access to oxygen. Cooper Power
Systems does not recommend applying Envirotemp FR3 fluid in free-breathing equipment.
Transformers using conservators fitted with bags or membranes, nitrogen preservation systems,
and sealed designs in general are suitable applications of Envirotemp FR3 fluid.
3.6 Causes of dissolved gas
Just as with mineral oil, gases in Envirotemp FR3 fluid are formed during normal aging processes,
thermal breakdown, operation of fuses or switches, by electrical defects, or during abnormal
events. The Envirotemp FR3 dissolved gas guide [16] contains analysis recommendations and
examples of normally operating and faulted transformers.
15

Dissolved Gas (ppm)
Dissolved Gas (ppm)
16
10,000
1,000
100
10
1
0
10,000
1,000
100
10
1
0
hydrogen H2 carbon
monoxide CO
hydrogen H2 carbon
monoxide CO
methane CH4 ethane C2H6 ethylene C2H4 acetylene C2H2 Total
Combustible
Gases
(a)
methane CH4 ethane C2H6 ethylene C2H4 acetylene C2H2 Total
Combustible
Gases
(b)
carbon dioxide
CO2
carbon dioxide
CO2
after fill
Sept `96
Dec `96
Jan `97
May `97
March `98
Feb `99
July `99
July `00
July `01
July `02
July `03
May `04
Sept '05
after fill
Oct `96
Nov `96
Jan `97
Jan `97
March `98
July `99
July `00
July `01
July `02
July `03
May `04
Sept '05
Figure 44. Dissolved gases over time of new 225 kVA distribution transformers filled with Envirotemp FR3 fluid:
(a) S/N 1429, (b) S/N 1430. Note the fairly high initial gas content. Fluid for power transformers is typically more
thoroughly processed.
3.7 Typical dissolved gas spectra
Dissolved gases over time for the two transformers described in 3.3 are shown in Figure 44. Both
have a higher proportion of ethane than is typical for a normally operating mineral oil transformer
– a signature of Envirotemp FR3 fluid [16].
3.8 Dissolved gas and ageing
To help develop an understanding of the gases dissolved in Envirotemp FR3 fluid as transformers
age, two sets of transformers were aged at 137°C, one set filled with mineral oil and the other with
Envirotemp FR3 fluid for the equivalent of 36 “normal” years. At 137°C, one IEEE "normal" year is
equivalent to 672 hours. Fluid samples for dissolved gas analysis were periodically taken. The gas
results are shown in Figure 45.
The gas generation rates as well as the quantities and proportions of gases in the mineral oil and
Envirotemp FR3 fluid are strikingly similar. Other than the characteristically higher proportion of
ethane in the Envirotemp FR3 fluid compared to mineral oil, the gases over time are comparable.

Dissolved Gas (ppm)
Dissolved Gas (ppm)
1,000,000
100,000
10,000
1,000
100
1,000,000
100,000
10,000
1,000
100
10
10
1
0
1
0
hydrogen H2 carbon
monoxide
CO
methane
CH4
ethane C2H6 ethylene
C2H4
(a)
hydrogen H2 carbon methane CH4 ethane C2H6 ethylene
monoxide CO
C2H4
(b)
acetylene
C2H2
acetylene
C2H2
Total
Combustible
Gases
Total
Combustible
Gases
carbon
dioxide CO2
carbon
dioxide CO2
Figure 45. Dissolved gas versus time. Test transformers filled with (a) mineral oil and (b) Envirotemp FR3 fluid
were run at an hottest spot temperature of 137°C using the IEEE C57.100 method. One IEEE "normal" year of
21.54 years is represented by 672 hrs at 137°C represents.
3.9 Sensitivity to oxygen of immersed material in air
Although Envirotemp FR3 fluid in bulk is relatively immune to oxidation due to air exposure, thin
films of the fluid can oxidize to form a polymer coating. It is the metal surfaces coated with thin
films that are prone to polymerization. A metal surface with a thin coating of Envirotemp FR3 fluid
exposed to shop air may become tacky in a matter of days. Porous surfaces, such as paper and
pressboard, impregnated with Envirotemp FR3 fluid can be exposed for months without becoming
tacky. They will, of course, absorb water from the atmosphere.
Following a sequence of tests, a large test tank filled with Envirotemp FR3 was put into a
warehouse without a cover, and was promptly forgotten. After several years, it was discovered
and the fluid tested. Aside from elevated dissipation factor and water content values, the fluid was
still in good condition. No film was seen on the surface of the fluid. There was no change in
viscosity, the definitive indicator of oxidation in Envirotemp FR3 fluid.
Ongoing experiments use the power factor models described in 3.2 to assess the effects of hot air
drying on impregnated surfaces.
initial
1 yrs
2 yrs
3 yrs
6 yrs
9 yrs
12 yrs
15 yrs
18 yrs
21 yrs
24 yrs
27 yrs
30 yrs
33 yrs
36 yrs
initial
1 yrs
2 yrs
3 yrs
6 yrs
9 yrs
12 yrs
15 yrs
18 yrs
21 yrs
24 yrs
27 yrs
30 yrs
33 yrs
36 yrs
17

18
An effect of hot air oven processing of Envirotemp FR3 fluid-impregnated coils was inadvertently
determined for us. Two transformers manufactured using Envirotemp FR3 fluid were tested for
power factor. The power factors of both transformers were higher than typically found in mineral
oil transformers. The power factor specification limit for mineral oil, 0.5%, was used as the limit for
these units. Because the dissipation factor of Envirotemp FR3 fluid is higher than that of mineral
oil, the power factor of the transformer also increases. Assuming a problem existed, the
transformers were reworked as if they were impregnated with mineral oil. The coils were ovendried
and the transformer retested. The power factor of the transformers went up due to the
increase in dissipation factor of the Envirotemp FR3 fluid as some oxidation occurred, instead of
down as expected. This process is used to dry mineral oil coils to lower the transformer power
factor. It also dried the Envirotemp FR3 fluid coils, but the increase in power factor due to
increased dissipation factor was larger than the reduction in power factor due to drier insulation.
3.10 Normal gassing
Dissolved gas levels in normally operating transformers filled with Envirotemp FR3 fluid are similar
to those found in equivalent mineral oil transformers. A feature unique to Envirotemp FR3 fluid is
its higher proportion of ethane compared to that found in normally operating mineral oil
transformers [16].
Dissolved Gas (ppm)
Dissolved Gas (ppm)
10,000
1,000
100
10
1
0
100,000
10,000
1,000
100
10
1
0
hydrogen H2 carbon methane CH4 ethane C2H6 ethylene
monoxide CO
C2H4
(a)
acetylene
C2H2
hydrogen H2 carbon methane CH4 ethane C2H6 ethylene C2H4 acetylene
monoxide CO
C2H2
(b)
Total
Combustible
Gases
Total
Combustible
Gases
carbon
dioxide CO2
carbon dioxide
CO2
mineral oil
FR3 fluid
mineral oil control
FR3 fluid control
mineral oil
FR3 fluid
mineral oil + Cu
FR3 fluid + Cu
Figure 46. Mineral oil and Envirotemp FR3 fluid subjected to (a) partial discharge and (b) thermal stress [12]

3.11 Effectiveness of gas extraction
Degassing Envirotemp FR3 fluid is done in the same way using the same equipment as used for
mineral oil. In order to keep the mineral oil flow rate through the processor and the same
transformer set time after filling, Envirotemp FR3 fluid should be heated to 80-85°C, compared to
60°C temperature typically used for mineral oil processing. If higher temperature is not feasible,
lower pressure in the degasser or slower flow rate can be used.
3.12 Interpretation of dissolved gas data
In general, the same basic interpretations of gas content used for mineral oil are used for
Envirotemp FR3 fluid [16]. The IEC “Duval” method has been the most reliable fault identification
method for Envirotemp FR3 fluid. Combinations of combustible gas generation rate and gas
proportions, along with the Duval method, are recommended. Applications of these methods are
given in the examples of [16].
Figure 46 shows the results of subjecting mineral oil and Envirotemp FR3 fluid to partial discharge
and thermal stress [12].
4. General properties
4.1 Fluid preservation
Envirotemp FR3 fluid is not suitable for long-term use in true free-breathing equipment. A
transformer equipped with a nitrogen preservation system or a conservator fitted with a bag or
membrane is suitable, as are sealed tank designs in general.
4.2 Materials compatibility
CPS has run multiple compatibility studies and found that Envirotemp FR3 fluid, relative to mineral
oil, has similar compatibility with materials used in the manufacture of transformers.
Core & Coil Materials
core steel
bare copper
bare aluminum
polyvinyl Formvar
copper magnet wire
aluminum magnet wire
conical mandrel
Kraft paper
pressboard
diamond paper
plain paper
tubing
crepe tubing
vulcanized fiber sheet
polyamide bias tape w/o
epoxy
polyvinyl acetate adhesive
Group A Materials
thermo set epoxy
Rynite 530 (PET)
high temperature Nylon
Rostone thermoset
polyester
fiberglass/epoxy
GPO3 polyester/glass
laminate
Amodel 1133
polyphthalimide
Mylar film (PET)
Masonite
porcelain - radio glaze
Nylon tie wrap
Carri-strap
Group B Materials
Rosite 3250
PVC wire jacket
Storm Trapper epoxy
coating & wires
pine block
Switchgear Components
tin-plated bus bar
silver-plated bus bar
Nylon tie wraps
fiberglass string
fiberglass string
bottle bushing
CT protector
cover gasket – wide
cover gasket – narrow
bushing gasket
GPO-3 polyester
semaphore window
auxiliary switches
shaft seal o-ring
semaphore gasket
bottle disc
tank connector
tank connector gasket
CT with wire leads
Elastomers
Buna-N
Nitrile NBR
Nitrile HNBR
Epichlorohydrin
Viton
Neoprene (used)
Cork/neoprene (used)
Sealants
Locktite PST592 pipe sealant
Locktite Vibra-Seal
Permatex 51D pipe joint
compound
Core Banding
Glass / Polyester
Dacron / Epoxy
Green Polyester Bands
Black Nylon Bands
Adhesives
PVA
Casein
Epoxy
Cyanoacrylate
Anaerobic (Thread lockers)
Acrylics (Tapes)
Tapes
polyester/glass with
thermo set rubber adhesive
thermosetting acrylic adhesive
Kraft paper w/ wheat gum adhesive
Miscellaneous
polyethylene naphthalate (PEN)
Rynite 350
HTN primary bushing
tap changer
bayonet fuse
Epoxy Paint (Two Part)
Core Epoxy
Phenolic (DETC)
Heat Shrink (Polyester)
Laminated Wood
TX Block Material
Nylon (6/6) Ty-wraps, Banding
Yoke Band Insulation
CTC (Bonded)
Epoxy Paint (Two Part)
Core Epoxy
19

Absolute Water Content (mg/kg)
4.3 Water absorption during maintenance and on-site drying
Water absorption from the atmosphere is shown in Figure 47. In terms of absolute water content,
Envirotemp FR3 fluid absorbs water at a faster rate than does mineral oil. In terms of relative
water content, mineral oil absorbs water at a faster rate. The same precautions taken to minimize
water absorption by mineral oil during maintenance should be taken for Envirotemp FR3 fluid.
600
500
400
300
200
100
0
0 500 1000 1500 2000 2500 3000
Exposure Time (hrs)
Envirotemp FR3 fluid
transformer oil
Relative Water Content
(% room temperature saturation)
100
80
60
40
20
0
0 500 1000 1500 2000 2500 3000
Exposure Time (hrs)
(a) (b)
Envirotemp FR3 fluid
transformer oil
Figure 47. Water absorption from laboratory ambient atmosphere of mineral oil and Envirotemp FR3 fluid as (a)
absolute water content and (b) relative water content.
20
4.4 Measures to avoid polymerization
Water uptake is almost always more of a concern than oxidation. Polymerization (oxidation leads
to the formation of oligomers, which eventually form polymers) is most likely to occur when thin
films of Envirotemp FR3 fluid on metal surfaces are exposed to air and sunlight (UV radiation). In
transformers, a free-breathing system will take years to show an increase in viscosity, the
definitive indication that oxidation is occurring. Long before the viscosity increases, the dissipation
factor will increase greatly, so ample warning is given in transformers routinely sampled.
Maintenance and repair tasks are most likely to expose thin films of Envirotemp FR3 fluid to the
atmosphere. Ideally, components impregnated with Envirotemp FR3 fluid or having thin films on
the surface will be immersed in Envirotemp FR3 fluid or mineral oil. The components could be
rinsed with mineral oil or stored in plastic bags of low oxygen permeability. Do not dry components
in hot air ovens.
4.5 Traces of other liquids
Envirotemp FR3 fluid is compatible with most dielectric fluids except silicone. The two do not mix,
and when put together separate into two phases. Silicone oil, even in low concentrations, may
cause foaming during the degassing process. Changes in Envirotemp FR3 fluid properties with
mineral oil content are shown in Figures 48-50.

Temperature ( o C)
350
300
250
200
150
0 2 4 6 8 10 20 40 60 80 100
Mineral Oil Content (%)
fire point
flash point
Figure 48. Flash and fire points versus mineral oil
content in Envirotemp FR3 fluid.
Kinematic Viscosity (mm 2 /s)
40
30
20
10
0
0 10 20 30 40 50 60 70 80 90 100
Mineral Oil Content (%)
viscosity at 40 o C
viscosity at 100 o C
Figure 49. Kinematic viscosity versus mineral oil
content in Envirotemp FR3 fluid.
Interfacial Tension (dynes/cm)
50
40
30
20
0 10 20 30 40 50 60 70 80 90 100
Mineral Oil Content (%)
Figure 50. Interfacial tension versus mineral oil
content in Envirotemp FR3 fluid.
4.6 Aging rate of thermal upgraded paper
Significant reductions in the aging rates of plain Kraft, cotton/Kraft, and thermally upgraded Kraft
are seen. Full-scale transformer accelerated aging tests, using the IEEE C57.100 method, are
described in [5]. These tests qualified the Envirotemp FR3 fluid/thermally upgraded Kraft paper
insulation system for 65°C average winding rise applications. Extending the tests qualified the
insulation system as a 75°C average winding rise system.
The results obtained in the full-scale tests led to an in-depth study of Envirotemp FR3 fluid
interactions. Sealed tube studies using the IEEE C57.100 method showed a much slower aging
rate of the thermally upgraded Kraft paper in Envirotemp FR3 fluid [6]. Plain (not thermally
upgraded) Kraft also show a significant decrease in aging [7], as did cotton/Kraft paper [8]. The
previous studies focused on new paper. Retrofill simulations were conducted showing a change
from the aging rate of paper/mineral oil to the aging rate of paper/Envirotemp FR3 fluid after the
retrofill [9]. The mechanisms responsible for the reduced aging rates are proposed in [10,11].
The thermally upgraded Kraft paper/Envirotemp FR3 fluid aging rates are applied to ANSI
standard transformer designs [13,15] using the aging equation derived from the sealed tube
studies [14].
21

4.7 Electrostatic charging and streaming electrification
The higher dissipation factor and lower resisitivity of Envirotemp FR3 fluid compared to those of
mineral oil should reduce the electrostatic charging and streaming electrification tendencies.
Cooper Power Systems is planning experiments to verify this.
5. Handling / oil processing
5.1 Processing rigs
Standard mineral oil processing rigs are commonly used with good results to process Envirotemp
FR3 fluid. The rig should be drained of mineral oil and flushed with Envirotemp FR3 fluid. It is then
ready for Envirotemp FR3 fluid processing. When finished, drain the Envirotemp FR3 fluid and
flush with mineral oil to return the rig to mineral oil use. Mineral oil is typically processed at about
60°C. To keep the same mineral oil flow rate through the processor and set time for the filled
transformer, the Envirotemp FR3 fluid should be processed around 80-85°C. The fluid degasses
easily at that temperature. If higher temperature operation of the rig is not possible, a reduced flow
rate may be needed.
5.2 Impregnating solid insulation
Envirotemp FR3 fluid penetrates solid insulation more slowly than does mineral oil. Allow double
the mineral oil impregnation time for Envirotemp FR3 fluid at the same temperature. Impregnation
times of laminated TX-2 is given in [17].
5.3 Influence of other oils and synthetic liquids during degassing
Avoid contamination with silicone oil. Most other dielectric fluids are compatible with Envirotemp
FR3 fluid and will degas normally.
5.4 Disposal methods
Envirotemp FR3 fluid is suitable as base stock used for biodiesel fuel production. Local lubrication
oil recyclers, restaurant grease recyclers, or fat rendering operations may also be possible.
Envirotemp FR3 fluid can be burned for heat recovery only if diluted to 10% or less in mineral oil.
It is not a hazardous waste for landfill disposal. If contaminated with hazardous materials, it must
be treated as such.
5.5 Hydrolytic stability
Envirotemp FR3 fluid, like other esters, can undergo hydrolysis. The hydrolysis reaction gives free
fatty acids. These acids typically are present in Envirotemp FR3 fluid and result in acid numbers
higher than those seen in mineral oil. The acid number quantifies the amount of acid but does not
advise its reactivity. Long chain fatty acids are less reactive than the shorter chain organic acids
found in mineral oil. A discussion of hydrolysis in Enirotemp FR3 fluid is given in [11].
5.6 Processing for water content
The water content of Envirotemp FR3 fluid is reduced in the same way as in mineral oil. Water
contents below 50 mg/kg are easily achieved. See 5.1.
5.7 Vapor phase processing
Cooper Power Systems has not had the opportunity to use vapor phase processing of Envirotemp
FR3 fluid coils. Envirotemp FR3 fluid is compatible with the kerosene type oils used in vapor
phase. Consult the manufacturer of the vapor phase equipment for recommendations.
References
[1] T.C. Wei, T.R. Blackburn, “A Report of the Partial Discharge Test Conducted on Envirotemp FR3 Fluid for
Cooper Power Systems”, School of Electrical Engineering and Telecommunications, University of New South
Wales, June 2004
[2] E. Gockenbach, H. Borsi, B. Dolata, “Research project on the comparison of electric and dielectric properties
of natural Ester fluid with a synthetic Ester and a Mineral based transformer oil: Report No. 2 (Partial
22

discharge behaviour, permittivity and dissipation factor tan d)”, Institute of Electric Power Systems, Division of
High Voltage Engineering, Schering-Institute, University of Hanover, Germany, Sept.-Nov. 2005
[3] D. Martin and Z.D. Wang, “A Comparative Study of the Impact of Moisture on the Dielectric Capability of
Esters for Large Power Transformers”, IEEE/DEIS Conf. on Electrical Insulation and Dielectric Phenomena,
Oct. 15-18, 2007, Kansas City, USA
[4] T.A. Prevost, “Dielectric Properties of Natural Esters and their Influence on Transformer Insulation System
Design and Performance”, IEEE/PES Transmission and Distribution Conf., May 21-26, Dallas USA
[5] C. P. McShane, G.A. Gauger, and J. Luksich, “Fire Resistant Natural Ester Dielectric Fluid and Novel
Insulation System for Its Use”, IEEE/PES Transmission & Distribution Conf., April 12-16, 1999, New Orleans,
USA
[6] C.P. McShane, K.J. Rapp, J.L. Corkran, G. A. Gauger, and J. Luksich, “Aging of Paper Insulation in Natural
Ester Dielectric Fluid”, IEEE/PES Transmission & Distribution Conf, Oct. 28 - Nov. 2, 2001, Atlanta, USA
[7] C.P. McShane, K.J. Rapp, J.L. Corkran, G. A. Gauger, and J. Luksich, “Aging of plain Kraft paper in natural
ester dielectric fluid”, IEEE/DEIS 14th International Conf. on Dielectric Liquids, July 7-12, 2002, Graz, Austria
[8] C.P. McShane, K.J. Rapp, J.L. Corkran, and J. Luksich, “Aging of cotton/Kraft blend insulation paper in natural
ester dielectric fluid”, TJ|H2b TechCon Asia-Pacific Condition Based Maintenance & Diagnostic Conf., May 7-9,
2003, Sidney, Australia
[9] C.P. McShane, J.L. Corkran, K.J. Rapp, and J. Luksich, “Aging of paper insulation retrofilled with natural ester
dielectric fluid”, IEEE/DEIS International Conf. on Electrical Insulation and Dielectric Phenomena, Oct. 19-22,
2003, Albuquerque, USA
[10] K.J. Rapp, C.P. McShane, and J. Luksich, “Interaction Mechanisms of Natural Ester Dielectric Fluid and Kraft
Paper”, IEEE/DEIS 15th International Conf. on Dielectric Liquids, June 26 - July 1, 2005, Coimbra, Portugal
[11] A.W. Lemm, K.J. Rapp, and J. Luksich, “Effect of Natural Ester (Vegetable Oil) Dielectric Fluid on the Water
Content of Aged Paper Insulation”, EIA/IEEE 10th Insucon International Electrical Insulation Conf., May 24-26,
2006, Birmingham, UK
[12] L. Lewand, “Laboratory evaluation of several synthetic and agricultural-based dielectric liquids”, Doble
International Client Conference, 5E, 2001, Boston, MA USA
[13] S. Durian, “Dielectric Fluid Relative Thermal Performance”, Engineering Development Report TP03-DR-006,
Cooper Power Systems, May 21, 2003
[14] J. Luksich, “IEEE Loading Guide A and B Factors for Envirotemp FR3 Fluid and Thermally Upgraded Kraft
Insulation”, Engineering Development Report TP03-DR-009, Rev. 1, Cooper Power Systems, June 12, 2003
[15] S. Durian, “Comparative Loading, Thermal, and Aging Performance of Thermally Upgraded Paper in Mineral
and Envirotemp FR3 Fluid”, Engineering Development Report TP03-DR-017, Cooper Power Systems, July 14,
2003
[16] “Envirotemp FR3 Fluid Dissolved Gas Guide”, R900-20-19, Cooper Power Systems, August 17, 2006
[17] T. Prevost, “Oil Impregnation Rate of Cooper FR3 Oil”, Wicor International Technical Report 3206, EHV
Weidmann, February 6, 2006
23