ASTM D2477-02

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 D2477-96 - 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 D2477-02e1 - 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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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
Designation:D 2477–02
Standard Test Method for
Dielectric Breakdown Voltage and Dielectric Strength of
1
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.
1. Scope down voltage and dielectric strength of different gases and
mixtures thereof for research and application evaluations and
1.1 This test method covers the determination of the dielec-
also as a field test. A more complete discussion of the
tric breakdown voltage and dielectric strength of insulating
significance of the dielectric strength test is given in the
gases used in transformers, circuit breakers, cables, and similar
Appendix.
apparatus as an insulating medium. The test method is appli-
cableonlytogaseswithboilingpointsbelowroomtemperature
5. Apparatus
at atmospheric pressure.
5.1 Electrical Apparatus:
1.2 This standard may involve hazardous materials, opera-
5.1.1 Transformer—The desired test voltage may be most
tions, and equipment. This standard does not purport to
readily obtained by a step-up transformer energized from a
address all of the safety concerns, if any, associated with its
variable low-voltage commercial power frequency source. The
use. It is the responsibility of the user of this standard to
transformer and controlling element shall be of such size and
establish appropriate safety and health practices and deter-
designthat,withthetestspecimeninthecircuit,thecrestfactor
mine the applicability of regulatory limitations prior to use.
(ratio of maximum to mean effective) of the 60-Hz test voltage
2. Referenced Documents does not differ by more than 65 % from that of a sinusoidal
wave over the upper half of the range of test voltage. The crest
2.1 ASTM Standards:
factor may be checked by means of an oscilloscope, a sphere
D 2864 Terminology Relating to Electrical Insulating Liq-
2 gap, or a peak-reading voltmeter in conjunction with an rms
uids and Gases
voltmeter. Where the waveform cannot be determined conve-
2.2 IEEE Standard:
1
3
niently, a transformer having a rating of not less than ⁄2 kVA
No. 4 Standard Techniques for High Voltage Testing
at the usual breakdown voltage shall be used. Transformers of
3. Terminology larger kVA capacity may be used, but in no case should the
powerfrequencyshortcircuitcurrentinthespecimencircuitbe
3.1 Definitions: For definitions of terms used in this test
outside the range of 1 to 10 mA/kV of applied voltage. This
method, refer to Terminology D 2864.
limitation of current may be accomplished by using a suitable
4. Significance and Use
external series resistor or by employing a transformer with
sufficient inherent reactance.
4.1 The dielectric breakdown voltage and dielectric strength
5.1.2 Circuit-Interrupting Equipment—The test transformer
of an insulating gas in a uniform field depends primarily on the
primary circuit shall be protected by an automatic circuit-
molecular structure of the gas. As different gases are mixed
breaking device capable of opening (as nearly instantaneously
either by plan or by contamination, any change in dielectric
as possible) on the current produced by the breakdown of the
breakdown voltage and dielectric strength will depend on both
test specimen; a circuit breaker that opens within 5 cycles may
the nature and proportion of the individual gases. This test
be used if the short-circuit current as described in 5.1.1 does
method uses plane and spherical electrodes which provide a
not exceed 200 mA.Aprolonged flow of current at the time of
nearly uniform field (see Appendix) in the area of electrical
breakdown causes contamination of the gases and damage of
discharge. It is suitable for determining the dielectric break-
theelectrodes,therebyaffectingthesubsequenttestresults,and
increasing the electrode and test cell maintenance and time of
1
This test method is under the jurisdiction of ASTM Committee D27 on
testing.
Electrical Insulating Liquids and Gases and is the direct responsibility of Subcom-
5.1.3 Voltage-Control Equipment—The rate of voltage rise
mittee D27.05 on Electrical Test.
1
shall be ⁄2 kV/s 6 20 %. Voltage control may be secured by a
Current edition approved April 10, 2002. Published June 2002. Originally
published as D 2477 – 66 T. Last previous edition D 2477 – 96. motor-driven variable-ratio-autotransformer. Preference is
2
Annual Book of ASTM Standards, Vol 10.03.
given to equipment having an approximately straight-line
3
Available from The Institute of Electrical and Electronic Engineers, Inc.
(IEEE), 445 Hoes Ln., P.O. Box 1331, Piscata
...