ASTM D2413-16(2022)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D2413 − 16 (Reapproved 2022)
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.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D202Test Methods for Sampling and Testing Untreated
Paper Used for Electrical Insulation
1.1 This practice covers the preparation of insulating paper
D257Test Methods for DC Resistance or Conductance of
and board impregnated with a liquid dielectric. Where this
Insulating Materials
practice states only “paper,” the same procedure shall apply to
D924Test Method for Dissipation Factor (or Power Factor)
board.
and Relative Permittivity (Dielectric Constant) of Electri-
1.2 This practice has been found practicable for papers
cal Insulating Liquids
havingnominalthicknessof0.05mm(2mil)andabove.Ithas
D1711Terminology Relating to Electrical Insulation
been used successfully for insulating board as thick as 6 mm
D1816Test Method for Dielectric Breakdown Voltage of
( ⁄4 in.) when care is taken to ensure the specimen geometry
Insulating Liquids Using VDE Electrodes
necessary for valid measurement of dielectric properties. Suit-
D1933Specification for Nitrogen Gas as an Electrical Insu-
able geometry depends on the electrode system used. Rigid
lating Material
solid opposing electrodes require flat specimens that have
D3394Test Methods for Sampling and Testing Electrical
essentially parallel surfaces.
Insulating Board
1.3 The values stated in SI units are to be regarded as D3426Test Method for Dielectric Breakdown Voltage and
DielectricStrengthofSolidElectricalInsulatingMaterials
standard. No other units of measurement are included in this
standard. Using Impulse Waves
1.4 This international standard was developed in accor-
3. Terminology
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the 3.1 Definitions—Use Terminology D1711 for definitions of
Development of International Standards, Guides and Recom- terms used in this practice and associated with electrical or
mendations issued by the World Trade Organization Technical
electronic materials.
Barriers to Trade (TBT) Committee.
4. Summary of Practice
2. Referenced Documents
4.1 The paper is heated and vacuum dried and the liquid
2.1 ASTM Standards:
dielectric degassed. The paper may be dried in loose form or
D117Guide for Sampling, Test Methods, and Specifications
assembled between electrodes. The liquid dielectric may be
for Electrical Insulating Liquids
heated and degassed prior to introducing it into the chamber
D149Test Method for Dielectric Breakdown Voltage and
containing the dried paper or it may be degassed as it is
DielectricStrengthofSolidElectricalInsulatingMaterials
introduced into the evacuated chamber containing the dried
at Commercial Power Frequencies
paper.Asufficient length of time is allowed for the impregnat-
D150Test Methods forAC Loss Characteristics and Permit-
ingprocessdependingontheapparentdensityofthepaperand
tivity (Dielectric Constant) of Solid Electrical Insulation
method of impregnation. The impregnated specimens are
subsequently tested for various selected electrical properties.
This practice is under the jurisdiction of ASTM Committee D09 on Electrical
5. Significance and Use
and Electronic Insulating Materials and is the direct responsibility of Subcommittee
D09.01 on Electrical Insulating Products.
5.1 Dissipation Factor and Relative Permittivity
Current edition approved May 1, 2022. Published May 2022. Originally
—Knowledge of these properties is important in the design of
approved in 1965. Last previous edition approved in 2016 as D2413–16. DOI:
10.1520/D2413-16R22.
electrical equipment such as cables, transformers, insulators,
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and so forth. The numerical product of these two properties of
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
a dielectric system is proportional to the energy loss converted
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. to heat, and is called its loss index (see Terminology D1711).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2413 − 16 (2022)
The energy loss reduces the efficiency of electrical equipment. 6. Apparatus
The heat produced tends to chemically degrade the dielectric
6.1 Drying and Impregnating Equipment:
material and may even lead to thermal runaway.Test results of
6.1.1 Impregnating Chamber—The chamber shall be
impregnated specimens can disclose significant differences
equipped with a thermal control unit capable of maintaining
between combinations of papers and oils that appear similar
selected temperatures as high as 115°C. The chamber shall
when the papers and the oils are tested separately. Dissipation
have a connection, through a suitable vapor trap, to a vacuum
factor, particularly at elevated temperatures, is often changed
pump capable of maintaining selected absolute pressures as
significantly by the presence of a small quantity of impurities
lowas75Pa(0.5Torr),asmeasuredbyasuitablevacuumgage
in either the liquid or the paper. This practice is useful in the
having a connection to the chamber separate from that of the
comparison of materials and in evaluating the effects of
vacuum pump. It shall be constructed of materials that will not
different papers on a given liquid. Judicious analysis of results
contaminate either the liquid dielectric or the paper, and shall
with respect to time, temperature, and field strength are useful
includeanappropriatelyvalvedentryfortheliquidplusabaffle
inpredictingtheperformanceandcapabilitiesofsystemsusing
for the purposes indicated in 9.3.
the paper and the liquid. For additional information on the
6.1.2 Vacuum Drying Equipment—For the liquid, if Proce-
significance of dissipation factor and relative permittivity, see
dure 1 (9.2.1) is to be used. This may be substantially a
Test Methods D150.
duplicate of the impregnating chamber except that a valved
5.2 Test Method for Dielectric Breakdown Voltage and vacuum-tightlineisrequiredfortransferringdriedliquidtothe
Dielectric Strength of Solid Electrical Insulating Materials at impregnating chamber. Baffles may be used to expose thin
Commercial Power Frequencies: films of incoming liquid to the drying and degassing effect of
5.2.1 Acomprehensive discussion of the significance of the heat and vacuum.
dielectric strength test as applied to solid, semi-solid, and
6.2 Equipment for Measuring Dissipation Factor (Power
liquidmaterialsisgiveninAppendixX1ofTestMethodD149.
Factor) and Permittivity of Liquid Dielectric—The equipment
Other factors peculiar to high-quality composite insulations,
and test cell shall be any three-terminal system meeting the
such as oil-impregnated papers, are considered in the follow-
requirements set forth in Test Method D924.
ing:
6.3 Equipment for Measuring Dielectric Strength at Com-
5.2.2 In tests involving high electrical stresses, immersion
mercial Power Frequencies:
ofcriticalpartsofatestcircuitinoilisawidelyusedtechnique
6.3.1 Theequipmentformeasuringthedielectricstrengthof
for inhibiting corona. However, it has limitations that must be
the paper shall be as described in Test Method D149, except
recognized when using the submerged electrode option of this
that the electrodes shall be as specified in Test Methods D202
practice (Note 1). Attack on the paper by corona generated in
or D3394, as applicable.
the surrounding fluid at electrode edges can occur whether the
6.3.2 Theequipmentfortestingthedielectricstrengthofthe
fluidisairoroil.Coronaoccursatconsiderablyhighervoltages
liquid shall be as described in Test Method D1816.
in oil than in air. Thick and dense papers are more likely to
cause discharge-initiated breakdowns. For interpretation of 6.4 Equipment for measuring impulse withstand strength
breakdown measurements consider the number of edge
and impulse breakdown dielectric strength shall be that which
breakdowns, implying discharge-initiated breakdowns. is specified in Test Method D3426.
NOTE 1—Two techniques are in use in the industry for testing
7. General Considerations
specimens for dielectric breakdown voltage. In one, the test is made with
the electrodes and test specimen submerged in the impregnating liquid
7.1 When undertaking an investiga
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