ASTM D877-87(1995)
(Test Method)Standard Test Method for Dielectric Breakdown Voltage of Insulating Liquids Using Disk Electrodes
Standard Test Method for Dielectric Breakdown Voltage of Insulating Liquids Using Disk Electrodes
SCOPE
1.1 This test method describes two procedures, A and B, for determining the electrical breakdown voltage of insulating liquid specimens. The breakdown test uses ac voltage in the power-frequency range from 45 to 65 Hz.
1.2 This test method is used to judge if the disk electrode breakdown voltage requirements are met for insulating liquids, as delivered from the manufacturer, that have never been filtered or dried. See Specification D3487, Specification D4652, and Guide D5222 for the minimum specified electrical breakdown. This test method should be used as recommended by professional organization standards such as IEEE C57.106.
1.3 Limitations of the Procedures
1.3.1 The sensitivity of this test method to the general population of contaminants present in a liquid sample decreases as applied test voltages used in this test method become greater than approximately 25 kV rms.
1.3.2 If the concentration of water in the sample at room temperature is less than 60 % of saturation, the sensitivity of this test method to the presence of water is decreased. For further information refer to RR: 327-1006.
1.3.3 The suitability for this test method has not been determined for a liquid's viscosity higher than 900 cSt at 40oC.
1.4 Procedure Applications--Procedure A is used to determine the breakdown voltage of liquids in which any insoluble breakdown products easily settle during the interval between the required repeated breakdown tests. These liquids include petroleum oils, hydrocarbons, and askarels (PCB) used as insulating and cooling liquids in transformers, cables, and similar apparatus.
1.4.1 Procedure B
1.4.1.1 This procedure is used to determine the breakdown voltage of liquids in which any insoluble breakdown products do not completely settle from the space between the disks during the 1-min interval required in Procedure A. Procedure B, modified in accordance with Section 17 of Test Methods D2225, is acceptable for testing silicone dielectric liquids.
1.4.1.2 Procedure B should also be applied for the determination of the breakdown voltage of liquid samples containing insoluble materials that settle from the specimen during testing. These may include samples taken from circuit breakers, load tap changers, and other liquids heavily contaminated with insoluble particulate material. These examples represent samples that may have large differences between replicate tests. The use of Procedure B will result in a more accurate value of breakdown voltage when testing such liquids.
1.4.1.3 Use Procedure B to establish the breakdown voltage of an insulating liquid where an ASTM specification does not exist or when developing a value for an ASTM guide or standard. Procedure A may be used once the single operator precision of 13.1 has been demonstrated.
1.5 Both the SI and inch-pound units are equally acceptable.
1.6 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.
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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 877 – 87 (Reapproved 1995) Method 5702—Federal Test
Method Standard No. 791b
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Dielectric Breakdown Voltage of Insulating Liquids Using
1
Disk Electrodes
This standard is issued under the fixed designation D 877; 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.
This standard has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Specifications and
Standards for the specific year of issue which has been adopted by the Department of Defense.
1. Scope D 484 Specification for Hydrocarbon Drycleaning Sol-
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vents
1.1 This test method covers a referee and a routine proce-
D 923 Test Method for Sampling Electrical Insulating Liq-
dure for determining the dielectric breakdown voltage of
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uids
insulating liquids. These procedures are applicable to liquid
D 1816 Test Method for Dielectric Breakdown Voltage of
petroleum oils, hydrocarbons, and askarels commonly used as
Insulating Oils of Petroleum Origin Using VDE Elec-
insulating and cooling mediums in cables, transformers, oil
3
trodes
circuit breakers, and similar apparatus. The referee procedure,
D 2225 Test Methods of Testing Silicone Fluids Used for
with modifications, is suitable for testing silicone fluids (see 3
Electrical Insulation
Test Methods D 2225). The referee procedure is also suitable
2.2 Institute of Electrical and Electronics Engineers Stan-
for testing alkylbenzenes. The suitability of either the referee or
dard:
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the routine procedure for testing liquids having viscosities
No. 4 Measurement of Voltage in Dielectric Test
2
exceeding 900 cSt (mm /s) (5000 SUS) at 40°C (104°F) has
3. Significance and Use
not been determined.
3.1 The dielectric breakdown voltage of an insulating liquid
1.2 This test method is recommended for acceptance tests
is of importance as a measure of the liquid’s ability to
on unprocessed insulating liquids received from vendors in
withstand electric stress without failure. It serves to indicate
tank cars, tank trucks, and drums. It may also be used for the
the presence of contaminating agents, such as water, dirt, moist
routine testing of liquids from power systems apparatus rated
cellulosic fibers, or conducting particles in the liquid, one or
230 kV and below.
more of which may be present in significant concentrations
1.3 This test method is not recommended for testing filtered,
when low dielectric breakdown values are found by test.
degassed, and dehydrated oil prior to and during the filling of
However, a high dielectric breakdown voltage does not indi-
power systems apparatus rated above 230 kV, or for testing
cate the absence of all contaminants; it may merely indicate
samples of such oil from apparatus after filling. Test Method
that the concentrations of contaminants that are present in the
D 1816 is more suitable for, and is recommended for, testing
liquid between the electrodes are not large enough to deleteri-
such oils.
ously affect the average breakdown voltage of the liquid when
tested by this method. See Appendix X1.
1.4 Both the SI and inch-pound units are equally acceptable.
1.5 This standard may involve hazardous materials, opera-
4. Apparatus
tions, and equipment. This standard does not purport to
4.1 Transformer—The desired test voltage may be most
address all of the safety concerns associated with its use. It is
readily obtained by a step-up transformer energized from a
the responsibility of the user of this standard to establish
variable low-voltage commercial power frequency source. The
appropriate safety and health practices and determine the
transformer and controlling element shall be of such size and
applicability of regulatory limitations prior to use.
design that, with the test specimen in the circuit, the crest factor
(ratio of maximum to mean effective) of the 60-Hz test voltage
2. Referenced Documents
shall not differ by more than6 5 % 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
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This test method is under the jurisdiction of ASTM Committee D-27 on
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Electrical Insulating Liquids and Gasesand is the direct responsibility of Subcom- Discontinued; see 1984 Annual Book of ASTM Standards, Vol 05.01.
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mittee D27.05on Electrical Test. Annual Book of ASTM Standards, Vol 10.03.
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Current edition approved Feb. 27, 1987. Published April 1987. Originally Av
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