ASTM D2477-02e1

Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Insulating Gases at Commercial Power Frequencies

SCOPE
1.1 This test method covers the determination of the dielectric breakdown voltage and dielectric strength of insulating gases used in transformers, circuit breakers, cables, and similar apparatus as an insulating medium. The test method is applicable only to gases with boiling points below room temperature at atmospheric pressure.
1.2 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Apr-2002
• ICS: 29.040.20 - Insulating gases
• Technical Committee: D27 - Electrical Insulating Liquids and Gases
• Drafting Committee: D27.05 - Electrical Test

Relations

• Replaces: ASTM D2477-02 - Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Insulating Gases at Commercial Power Frequencies
• Effective Date: 10-Apr-2002
• Replaced By: ASTM D2477-02e2 - Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Insulating Gases at Commercial Power Frequencies
• Effective Date: 10-Apr-2002

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
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Designation:D 2477–02
Standard Test Method for
Dielectric Breakdown Voltage and Dielectric Strength of
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Insulating Gases at Commercial Power Frequencies
This standard is issued under the fixed designation D 2477; 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 (e) indicates an editorial change since the last revision or reapproval.
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e NOTE—Sections 9.1.1 and 9.1.3 were corrected editorially in September 2005.
1. Scope the nature and proportion of the individual gases. This test
method uses plane and spherical electrodes which provide a
1.1 This test method covers the determination of the dielec-
nearly uniform field (see Appendix) in the area of electrical
tric breakdown voltage and dielectric strength of insulating
discharge. It is suitable for determining the dielectric break-
gases used in transformers, circuit breakers, cables, and similar
down voltage and dielectric strength of different gases and
apparatus as an insulating medium. The test method is appli-
mixtures thereof for research and application evaluations and
cableonlytogaseswithboilingpointsbelowroomtemperature
also as a field test. A more complete discussion of the
at atmospheric pressure.
significance of the dielectric strength test is given in the
1.2 This standard may involve hazardous materials, opera-
Appendix.
tions, and equipment. This standard does not purport to
address all of the safety concerns, if any, associated with its
5. Apparatus
use. It is the responsibility of the user of this standard to
5.1 Electrical Apparatus:
establish appropriate safety and health practices and deter-
5.1.1 Transformer—The desired test voltage may be most
mine the applicability of regulatory limitations prior to use.
readily obtained by a step-up transformer energized from a
2. Referenced Documents variable low-voltage commercial power frequency source. The
transformer and controlling element shall be of such size and
2.1 ASTM Standards:
designthat,withthetestspecimeninthecircuit,thecrestfactor
D 2864 Terminology Relating to Electrical Insulating Liq-
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(ratio of maximum to mean effective) of the 60-Hz test voltage
uids and Gases
does not differ by more than 65 % from that of a sinusoidal
2.2 IEEE Standard:
3 wave over the upper half of the range of test voltage. The crest
No. 4 Standard Techniques for High Voltage Testing
factor may be checked by means of an oscilloscope, a sphere
3. Terminology gap, or a peak-reading voltmeter in conjunction with an rms
voltmeter. Where the waveform cannot be determined conve-
3.1 Definitions: For definitions of terms used in this test
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niently, a transformer having a rating of not less than ⁄2 kVA
method, refer to Terminology D 2864.
at the usual breakdown voltage shall be used. Transformers of
4. Significance and Use
larger kVA capacity may be used, but in no case should the
powerfrequencyshortcircuitcurrentinthespecimencircuitbe
4.1 The dielectric breakdown voltage and dielectric strength
outside the range of 1 to 10 mA/kV of applied voltage. This
of an insulating gas in a uniform field depends primarily on the
limitation of current may be accomplished by using a suitable
molecular structure of the gas. As different gases are mixed
external series resistor or by employing a transformer with
either by plan or by contamination, any change in dielectric
sufficient inherent reactance.
breakdown voltage and dielectric strength will depend on both
5.1.2 Circuit-Interrupting Equipment—The test transformer
primary circuit shall be protected by an automatic circuit-
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This test method is under the jurisdiction of ASTM Committee D27 on
breaking device capable of opening (as nearly instantaneously
Electrical Insulating Liquids and Gases and is the direct responsibility of Subcom-
as possible) on the current produced by the breakdown of the
mittee D27.05 on Electrical Test.
test specimen; a circuit breaker that opens within 5 cycles may
Current edition approved April 10, 2002. Published June 2002. Originally
published as D 2477 – 66 T. Last previous edition D 2477 – 96. be used if the short-circuit current as described in 5.1.1 does
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Annual Book of ASTM Standards, Vol 10.03.
not exceed 200 mA.Aprolonged flow of current at the time of
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Available from The Institute of Electrical and Electronic Engineers, Inc.
breakdown causes contamination of the gases and damage of
(IEEE), 445 Hoes Ln., P.O. Box 1331, Piscataway, NJ 08854-1331.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D 2477–02
theelectrodes,therebyaffectingthesubsequenttestresults,and 5.2 Evacuation
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