ASTM D1934-95(2000)
(Test Method)Standard Test Method for Oxidative Aging of Electrical Insulating Petroleum Oils by Open-Beaker Method
Standard Test Method for Oxidative Aging of Electrical Insulating Petroleum Oils by Open-Beaker Method
SCOPE
1.1 This test method describes two procedures for subjecting electrical insulating oils to oxidative aging:
1.1.1 Procedure A , without a metal catalyst, and
1.1.2 Procedure B , with a metal catalyst.
1.2 This test method is applicable to oils used as impregnating or pressure media in electrical power transmission cables if less than 10% of the oil evaporates during the aging procedures. It applies and is generally useful primarily in the evaluation and quality control of unused oils, either inhibited or uninhibited.
1.3 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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Designation:D 1934–95 (Reapproved 2000)
Standard Test Method for
Oxidative Aging of Electrical Insulating Petroleum Oils by
Open-Beaker Method
This standard is issued under the fixed designation D 1934; 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 3. Terminology
1.1 This test method describes two procedures for subject- 3.1 Definitions of Terms Specific to This Standard:
ing electrical insulating oils to oxidative aging: 3.1.1 metal catalyst—any metal (for example, copper) that
1.1.1 Procedure A, without a metal catalyst, and eitherincreasestherateofoxidationoftheoilorreactswiththe
1.1.2 Procedure B, with a metal catalyst. oxidation products to increase oil dielectric loss.
1.2 This test method is applicable to oils used as impreg- 3.1.2 oxidative aging—exposure of oil to oxygen under
nating or pressure media in electrical power transmission certain specified conditions.
cables if less than 10 % of the oil evaporates during the aging
4. Summary of Test Method
procedures. It applies and is generally useful primarily in the
evaluation and quality control of unused oils, either inhibited 4.1 A300 mLvolume of oil, contained in 400 mLbeaker is
aged for 96 h in a circulating-air oven controlled at 115°C,
or uninhibited.
1.3 This standard does not purport to address all of the either with or without the presence of catalyst.
safety concerns, if any, associated with its use. It is the
5. Significance and Use
responsibility of the user of this standard to establish appro-
5.1 Open-beaker oxidative aging methods have been used
priate safety and health practices and determine the applica-
for many years in laboratories of oil companies, electrical
bility of regulatory limitations prior to use.
equipment manufacturers, and electric utility companies inter-
2. Referenced Documents
estedinthestabilityofelectricalinsulatingoilsunderoxidative
2.1 ASTM Standards: conditions. They are particularly useful as a check on the
D 664 Test Method forAcid Number of Petroleum Products continuity of production and shipment of insulating oils. They
are also useful as process and product checks for applicable
by Potentiometric Titration
D 923 Test Method for Sampling Electrical Insulating Liq- type oils.
5.2 Specification limits for oils subjected to open-beaker
uids
D 924 TestMethodforDissipationFactor(orPowerFactor) oxidative aging by this method are established by agreement
between individual producers and consumers of applicable
and Relative Permittivity (Dielectric Constant) of Electri-
cal Insulating Liquids type oils. These properties of the oil involved in specification
limits for aging stability may be measured after the oxidative
D 1169 Test Method for Specific Resistance (Resistivity) of
Electrical Insulating Liquids aging (and sometimes before aging) by appropriate test meth-
ods such as Test Method D 924, Test Method D 1169, and Test
E 145 Specification for Gravity-Convection and Forced-
Ventilation Ovens Method D 664.
E 177 Practice for Use of the Terms Precision and Bias in
4 6. Apparatus
ASTM Test Methods
6.1 Oven, electrically heated, thermostatically controlled,
capable of maintaining a constant temperature of 115 6 1°C
(239 6 2°F). Use an oven with a testing chamber large enough
This test method is under the jurisdiction of ASTM Committee D-27 on
to test the anticipated number of test specimens at one time.A
Electrical Insulating Liquids and Gasesand is the direct responsibility of Subcom-
uniformity of temperature within 6 1 % of the differential
mittee D27.06on Chemical Test.
Current edition approved Dec. 10, 1995. Published February 1996. Originally
between oven and ambient temperatures is required. (See Note
published as D 1934 – 62 T. Last previous edition D 1934 – 89a.
1.) Circulate air in the chamber with a low velocity fan during
Annual Book of ASTM Standards, Vol 05.01.
the aging period. The volume and condition of the circulated
Annual Book of ASTM Standards, Vol 10.03.
Annual Book of ASTM Standards, Vol 14.02. air is not considered to be critical. It is recommended that the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 1934
oven provide several air changes per hour, and that vapors and One good method of cleaning copper hanks is to immerse the
fumes be removed if present. hank for 30 s in a 10 % solution of hydrochloric acid (HCl),
afterwhichthehankisrinsedthreetimesindistilledwaterthen
NOTE 1—Refer to Specification E 145 for the measurement of the
in acetone and air dried. The cleaned hank should be handled
temperature uniformity of the oven.
with clean tongs.
6.1.1 Procedure A—For test specimens aged in the absence
of a metal catalyst the choice of a suitable oven design is not
8. Procedure A—Aging Without a Metal Catalyst
critical. Either fixed- or rotating-shelf stage ovens of satisfac-
8.1 Obtain the oil sample in accordance with Methods
tory thermal quality may be used, although a rotating-shelf
D 923.
oven is preferred. If a fixed-shelf oven is used, it is recom-
8.2 Adjust the oven temperature to 115 6 1°C.
mended that test specimen positions within the oven be
8.3 Pour without preheating 300 mL of the test specimen to
changed periodically (for example, at daily intervals) to mini-
be tested into a clean dry 400-mL beaker. Oil depth in the
mize the effects of any temperature differentials that may exist.
beaker will be approximately 75 mm. Measure the mass of the
6.1.2 Procedure B—When a metal catalyst, such as copper,
oil before test.
is used, the rate of oxidation usually is increased, and the
8.4 Place the beaker containing the test specimen in the
procedure becomes sensitive to movement of the oil past the
preheated oven. To minimize temperature fluctuation it is
metal surface. An aging oven equipped with a slowly rotating
desirable to place all test specimens in the oven at the same
shelf has been adopted for uniformity when a metal catalyst is
time.
used. Other oven designs having satisfactory thermal quality
8.5 Start the oven shelf into rotation if the oven is so
and a rotating shelf may be used.
equipped.
6.2 Beaker, boros
...
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