ASTM D2413-99(2005)

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An American National Standard
Designation:D2413–99 (Reapproved 2005)
Standard Practice for
Preparation of Insulating Paper and Board Impregnated with
a Liquid Dielectric
This standard is issued under the fixed designation D2413; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D924 Test Method for Dissipation Factor (or Power Factor)
and Relative Permittivity (Dielectric Constant) of Electri-
1.1 This practice covers the preparation of insulating paper
cal Insulating Liquids
and board impregnated with a liquid dielectric. Where this
D1711 Terminology Relating to Electrical Insulation
practice states only “paper,” the same procedure shall apply to
D1816 Test Method for Dielectric Breakdown Voltage of
board.
InsulatingOilsofPetroleumOriginUsingVDEElectrodes
1.2 This practice has been found practicable for papers
D1933 Specification for Nitrogen Gas as an Electrical
having nominal thickness of 0.05 mm (2 mil) and above. It has
Insulating Material
been used successfully for insulating board as thick as 6 mm
1 D3394 Test Methods for Sampling and Testing Electrical
( ⁄4 in.) when care is taken to ensure the specimen geometry
Insulating Board
necessary for valid measurement of dielectric properties. Suit-
D3426 Test Method for Dielectric Breakdown Voltage and
able geometry depends on the electrode system used. Rigid
Dielectric Strength of Solid Electrical Insulating Materials
solid opposing electrodes require flat specimens that have
Using Impulse Waves
essentially parallel surfaces.
1.3 The values stated in SI units are to be regarded as the
3. Terminology
standard.
3.1 Definitions—Use Terminology D1711 for definitions of
2. Referenced Documents terms used in this practice and associated with electrical or
electronic materials.
2.1 ASTM Standards:
D117 GuideforSampling,TestMethods,andSpecifications
4. Summary of Practice
for Electrical Insulating Oils of Petroleum Origin
4.1 The paper is heated and vacuum dried and the liquid
D149 Test Method for Dielectric Breakdown Voltage and
dielectric degassed. The paper may be dried in loose form or
Dielectric Strength of Solid Electrical Insulating Materials
assembled between electrodes. The liquid dielectric may be
at Commercial Power Frequencies
heated and degassed prior to introducing it into the chamber
D150 Test Methods for AC Loss Characteristics and Per-
containing the dried paper or it may be degassed as it is
mittivity (Dielectric Constant) of Solid Electrical Insula-
introduced into the evacuated chamber containing the dried
tion
paper.Asufficient length of time is allowed for the impregnat-
D202 Test Methods for Sampling and Testing Untreated
ing process depending on the apparent density of the paper and
Paper Used for Electrical Insulation
method of impregnation. The impregnated specimens are
D257 Test Methods for DC Resistance or Conductance of
subsequently tested for various selected electrical properties.
Insulating Materials
5. Significance and Use
This practice is under the jurisdiction of ASTM Committee D09 on Electrical
5.1 Dissipation Factor and Relative Permittivity—
and Electronic Insulating Materials and is the direct responsibility of Subcommittee
Knowledge of these properties is important in the design of
D09.19 on Dielectric Sheet and Roll Products.
electrical equipment such as cables, transformers, insulators,
Current edition approved May 10, 1999. Published June 1999. Originally
etc. The numerical product of these two properties of a
approved in 1965. Last previous edition approved in 1998 as D2413 – 87 (1998).
DOI: 10.1520/D2413-99R05.
dielectricsystemisproportionaltotheenergylossconvertedto
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
heat, and is called its loss index (seeTerminology D1711).The
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
energy loss reduces the efficiency of electrical equipment. The
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. heat produced tends to chemically degrade the dielectric
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D2413–99 (2005)
material and may even lead to thermal runaway. Test results of 6. Apparatus
impregnated specimens can disclose significant differences
6.1 Drying and Impregnating Equipment:
between combinations of papers and oils that appear similar
6.1.1 Impregnating Chamber—The chamber shall be
when the papers and the oils are tested separately. Dissipation
equipped with a thermal control unit capable of maintaining
factor, particularly at elevated temperatures, is often changed
selected temperatures as high as 115 °C. The chamber shall
significantly by the presence of a small quantity of impurities
have a connection, through a suitable vapor trap, to a vacuum
in either the liquid or the paper. This practice is useful in the
pump capable of maintaining selected absolute pressures as
comparison of materials and in evaluating the effects of
lowas75Pa(0.5Torr),asmeasuredbyasuitablevacuumgage
different papers on a given liquid. Judicious analysis of results
having a connection to the chamber separate from that of the
with respect to time, temperature, and field strength should be
vacuum pump. It shall be constructed of materials that will not
useful in predicting the performance and capabilities of sys-
contaminate either the liquid dielectric or the paper, and shall
tems using the paper and the liquid. For additional information
includeanappropriatelyvalvedentryfortheliquidplusabaffle
on the significance of dissipation factor and relative permittiv-
for the purposes indicated in 9.3.
ity, see Test Methods D150.
6.1.2 Vacuum Drying Equipment—For the liquid, if Proce-
5.2 Test Method for Dielectric Breakdown Voltage and
dure 1 (9.2.1) is to be used. This may be substantially a
Dielectric Strength of Solid Electrical Insulating Materials at
duplicate of the impregnating chamber except that a valved
Commercial Power Frequencies:
vacuum-tight line is required for transferring dried liquid to the
5.2.1 Acomprehensive discussion of the significance of the
impregnating chamber. Baffles may be used to expose thin
dielectric strength test as applied to solid, semi-solid, and
films of incoming liquid to the drying and degassing effect of
liquid materials is given inAppendix X1 ofTest Method D149.
heat and vacuum.
Other factors peculiar to high-quality composite insulations,
6.2 Equipment for Measuring Dissipation Factor (Power
such as oil-impregnated papers, are considered in the follow-
Factor) and Permittivity of Liquid Dielectric—The equipment
ing:
and test cell shall be any three-terminal system meeting the
5.2.2 In tests involving high electrical stresses, immersion requirements set forth in Test Method D924.
ofcriticalpartsofatestcircuitinoilisawidelyusedtechnique
6.3 Equipment for Measuring Dielectric Strength at Com-
for inhibiting corona. However, it has limitations that must be
mercial Power Frequencies:
recognized when using the submerged electrode option of this
6.3.1 Theequipmentformeasuringthedielectricstrengthof
practice (Note 1). Attack on the paper by corona generated in
the paper shall be as described in Test Method D149, except
the surrounding fluid at electrode edges can occur whether the
that the electrodes shall be as specified in Test Methods D202
fluidisairoroil.Coronaoccursatconsiderablyhighervoltages
or D3394, as applicable.
in oil than in air. Thick and dense papers are more likely to
6.3.2 The equipment for testing the dielectric strength of the
cause discharge-initiated breakdowns. For interpretation of
liquid shall be as described in Test Method D1816.
breakdown measurements the number of edge breakdowns,
6.4 Equipment for measuring impulse withstand strength
implying discharge-initiated breakdowns, should be consid-
and impulse breakdown dielectric strength shall be that which
ered.
is specified in Test Method D3426.
NOTE 1—Two techniques are in use in the industry for testing speci-
7. General Considerations
mens for dielectric breakdown voltage. In one, the test is made with the
electrodes and test specimen submerged in the impregnating liquid while
7.1 When undertaking an investigation into the electrical
in the other the electrodes are not submerged, that is, the specimen is
properties of various papers that are to be
...