1、Designation: D2864 17aStandard Terminology Relating toElectrical Insulating Liquids and Gases1This standard is issued under the fixed designation D2864; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n
2、umber in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONThe definitions contained in this terminology pertain to terms as they are used in conjunction withfluid insulating materials. Insofar a
3、s possible, the definitions are consistent with accepted generalusage, and may also contain additional information deemed to be of value in testing of fluid insulatingmaterials.1. Referenced Documents1.1 ASTM Standards:2D611 Test Methods for Aniline Point and Mixed AnilinePoint of Petroleum Products
4、 and Hydrocarbon SolventsD2007 Test Method for Characteristic Groups in RubberExtender and Processing Oils and Other Petroleum-Derived Oils by the Clay-Gel Absorption Chromato-graphic MethodD2140 Practice for Calculating Carbon-Type Compositionof Insulating Oils of Petroleum OriginD2300 Test Method
5、for Gassing of Electrical InsulatingLiquids Under Electrical Stress and Ionization (ModifiedPirelli Method)D2500 Test Method for Cloud Point of Petroleum Productsand Liquid FuelsD3117 Test Method for Wax Appearance Point of DistillateFuels (Withdrawn 2010)3E355 Practice for Gas Chromatography Terms
6、and Relation-ships2. Terminologyac, nsymbol used to designate an electric voltage or currentwhose amplitude varies periodically as a function of time, itsaverage value over one complete period being zero. Onecomplete repetition of the wave pattern is referred to as aCYCLE, and the number of cycles o
7、ccurring in one secondis called the FREQUENCY, measured in hertz (Hz). Forexample, the electricity supplied by commercial utilitycompanies in the United States is, in most localities, 60 Hz,although other frequencies may be encountered.acid treating, na refining process in which an unfinishedpetrole
8、um insulating oil is contacted with sulfuric acid toimprove its color, odor, stability, and other properties.ac loss characteristics, nthose properties of a dielectric orinsulation system (such as dissipation factor, power factor,and loss index) that may be used as a measure of the poweror energy lo
9、sses that would result from the use of suchmaterial in an ac electric field.additive, na chemical compound or compounds added to aninsulating fluid for the purpose of imparting new propertiesor altering those properties which the fluid already has.ambient temperature, nthe temperature of the surroun
10、dingatmosphere as determined by an instrument shielded fromdirect or reflected rays of the sun.aniline point, nthe minimum temperature for completemiscibility of equal volumes of aniline and the sample undertest. See Test Methods D611. In comparing two samples ofsimilar molecular weight, the aniline
11、 point can be used as ameans of comparing aromatic content of the two samples. Aproduct of high aniline point will be low in aromatics andnaphthenes, and therefore high in paraffins.API gravity, nan arbitrary scale developed by the AmericanPetroleum Institute and frequently used in reference topetro
12、leum insulating oil. The relationship between APIgravity and specific gravity 60/60F is defined by thefollowing:Deg API Gravity at 60F 5 141.5/sp gr 60/60F! 2 131.5aromatics, nthat class of organic compounds which behavechemically like benzene. They are cyclic unsaturated organic1This terminology is
13、 under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquids and Gasesand is the direct responsibility of Subcom-mittee D27.15 on Planning Resource and Development.Current edition approved March 1, 2017. Published March 2017. Originallyapproved in 1970. Last previous edition approve
14、d in 2017 as D2864 17. DOI:10.1520/D2864-17A.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approv
15、ed version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization e
16、stablished in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1compounds that can sustain an induced electronic ringcurrent due to delocalization of electrons aroun
17、d the ring.DISCUSSIONEmpirically, the aromatic portion of a mineral insulat-ing oil can be estimated by correlation with physical properties (SeeTest Method D2140), or by selective adsorption on clay-gel (See TestMethod D2007).askarel, na generic term for a group of synthetic, fire-resistant, chlori
18、nated aromatic hydrocarbons used as electri-cal insulating liquids. They have a property under arcingconditions such that any gases produced will consist pre-dominantly of noncombustible hydrogen chloride with lesseramounts of combustible gases.atomic absorption, nthe absorption of radiant energy by
19、ground state atoms. Substances when dispersed as an atomicvapor will absorb characteristic radiations identical to thosewhich the same substances can emit. This property is thebasis for analysis by atomic absorption spectroscopy.capacitivity, nthe same as permittivity, relative.color, na quality of
20、visible phenomena of insulating fluids,the numerical value for which is derived by comparing thisquality using transmitted light with that of a series ofnumbered reference bustible gases, nflammable gases formed from break-down (partial or complete) of some insulating materialssubjected to electrica
21、l or thermal stress, or both.conductance, nthe ratio of the current carried through amaterial to the difference in potential applied across thematerial. It is the reciprocal of resistance . The unit is:(ohm)1or siemens.DISCUSSION1Conductance is a general term. Specific referencemay be made to conduc
22、tance dc and conductance ac.DISCUSSION2For dielectrics the conductance may be dependenton the electrification time.conductance, apparent dc, nthe dc conductance measuredat the end of a specific electrification time. The “apparent dcconductance” is the reciprocal of the “apparent dc resis-tance.” The
23、 unit is: (ohm)1or siemens.DISCUSSIONThe term “apparent dc conductance” is used to distin-guish the current-voltage relationship found in electrical insulatingmaterials, where the current (leakage plus absorption) usually decreaseswith time, from the relationship found in metallic conductors where t
24、hesteady-state current is reached in a fraction of a second.conductance, dc, nthe ratio of the total current (in amperes)passing through a material to the dc voltage (in volts) appliedbetween two electrodes that are in contact with, or immersedin a specimen. The “dc conductance” is the reciprocal of
25、 the“dc resistance.” The unit is: (ohm)1or siemens.conductivity, nthe ratio of the current density carriedthrough a specimen to the potential gradient paralleling thecurrent. This is numerically equal to the conductance be-tween opposite faces of a unit cube of liquid. It is thereciprocal of resisti
26、vity.DISCUSSION1Conductivity is a general term. Specific referencemay be made to conductivity, dc.DISCUSSION2For dielectrics the conductivity may be dependenton the electrification time. (See also conductivity, apparent dcvolume and conductivity, dc volume.)conductivity, apparent dc volume, nthe “dc
27、 volume con-ductivity” measured at the end of a specified electrificationtime. It is the reciprocal of the apparent dc volume resistiv-ity. The unit most commonly used is: (ohm-centimetre)1orsiemens per centimetre. The SI unit is (ohm-metre)1.conductivity, dc, nthe ratio of the current density passi
28、ngthrough a specimen at a given instant of time and underprescribed conditions, to the dc potential gradient parallelingthe current. It is the reciprocal of the dc resistivity. Incommon practice the “dc conductivity” is numerically equalto the “dc conductance” between opposite faces of a centi-metre
29、 cube of liquid. The unit is: (ohm-centimetre)1orsiemens per centimetre. The SI unit is: (ohm-metre)1.DISCUSSIONThe “dc conductivity” may contain components of bothsurface conductance and volume conductance, but, in general, surfaceeffects are not common in measurements on fluid dielectrics. Theprop
30、erty most commonly measured is either the “dc volume conduc-tivity” or the “apparent dc volume conductivity.”conductivity, dc volume, nthe property of a material thatpermits the flow of electricity through its volume. It isnumerically equal to the ratio of the steady-state currentdensity to the stea
31、dy direct voltage gradient parallel with thecurrent in the material. The dc volume conductivity is thereciprocal of the dc volume resistivity. The unit commonlyused is: (ohm-centimetre)1or siemens per centimetre. TheSI unit is (ohm-metre)1.DISCUSSIONFor electrical insulating materials the time requi
32、red forthe steady-state current to be reached may be very long; from severalminutes to several months may be required.corona, na luminous discharge due to ionization of the airsurrounding an electrode, caused by the high electric fieldstrength in the vicinity of the electrode, exceeding a certaincri
33、tical (that is, threshold) value.corona effect, nlight emitted in the UV range of theelectromagnetic spectrum by electronically excited mol-ecules that have reached a singlet state and have notconsumed the absorbed energy by other physical process.corona (partial discharge) inception voltage, CIV, n
34、thelowest voltage at which continuous partial discharge (orcorona) exceeding a specified intensity is observed as theapplied voltage is gradually increased. Where the appliedvoltage is alternating, the CIV is expressed as 1/=2 of thepeak voltage.corona (partial discharge) extinction voltage, CEV, nt
35、hehighest voltage at which partial discharge (or corona) nolonger exceeds a specified intensity as the applied voltage isgradually decreased from a value above the corona inceptionvoltage. Where the applied voltage is alternating the CEV isexpressed as 1/=2 of the peak voltage.corrosive sulfur, nele
36、mental sulfur and thermally unstablesulfur compounds in electrical insulating oil that can causecorrosion of certain transformer metals such as copper andsilver.D2864 17a2dc, nsymbol used to designate an electric voltage or currentwhose amplitude does not vary periodically with respect totime, as fo
37、r example the output of a chemical cell or that ofa thermocouple. The term is also applied to the output ofsuch devices as dynamos and rectifiers, whose amplitude isnot strictly time-invariant.dew-point temperature, nthe temperature (above 0C) towhich a gas or vapor must be cooled at constant pressu
38、re andconstant water-vapor composition in order for saturation tooccur.DISCUSSIONAt temperatures below 0C, vapor may first be noticedin the form of frost. It is common to refer to the temperature at whichthis occurs as the frost-point temperature. Dew-point temperatures alsoexist for other gas or va
39、por systems in which saturation with respect toa substance other than water vapor can occur.dielectric, na medium in which it is possible to maintain anelectric field with little supply of energy from outsidesources. The energy required to produce the electric field isrecoverable, in whole or in par
40、t. A vacuum, as well as anyinsulating material is a dielectric.dielectric breakdown voltage, nthe potential difference atwhich electrical failure occurs in an electrical insulatingmaterial or insulation structure, under prescribed test condi-tions.dielectric constant, n see dielectric constant, rela
41、tive (es-pecially Note 2). (See also permittivity (especially Note 2).)dielectric constant, absolute, nthe same as permittivity.dielectric constant, relative, nthe same as permittivity,relative.DISCUSSION1Current practice including international usage is toprefer the term relative permittivity.DISCU
42、SSION2Common usage has been to drop the term “relative”and simply use dielectric constant when the dimensionless ratio is thequantity being referred to.dielectric failure, nthe failure of an element in a dielectriccircuit that exists when the insulating element becomesconducting. This event may take
43、 the form of a gradualincrease in current exceeding a specified value, but it usuallytakes the form of an almost instantaneous charge transferaccompanied by collapse of the insulating properties andpartial of complete localized destruction of the dielectricmedium. In the case of liquids and gases th
44、e failure may beself-healing.dielectric strength, na property of an insulating materialdescribed by the average voltage gradient at which electricbreakdown occurs under specific conditions of test.dissipation factor, D, nthe ratio of the loss index to itsrelative permittivity orD 5 “/It is also the
45、tangent of its loss angle, , or the cotangentof its phase angle, . The dissipation factor is related to thepower factor, PF, by the following equation:D 5 PF/=1 2 PF !2DISCUSSIONIt may be expressed as D = tan = cotan =G/Cp5 1/CpRp5 RsCswhere G is the equivalent parallel ac conductance, Cpis the par-
46、allel capacitance, Rpis the equivalent parallel ac resistance, Csisthe series capacitance, and Rsis the equivalent series resistance.dissipation factor, dielectric, nsame as dissipation factor.dissolved water, nwater that is in solution interspersedbetween molecules of insulating liquid.electric con
47、stant, n the same as permittivity of free space.electric creepage strength, nthe average voltage gradientunder specific conditions of test and for a specific electrodeconfiguration, at which dielectric failure occurs along theinterface between a solid insulating material and the fluid inwhich it is
48、immersed, or at the interface between two solidsthat are in close physical contact with each other but are notbonded chemically. Dielectric creepage failure may result intracking.electrical discharge, na discontinuous movement of electri-cal charges through an insulating medium, initiated byelectron
49、 avalanches and supplemented by secondary pro-cesses.electrification time, nthe time during which a steady directpotential is applied to electrical insulating materials beforethe current is measured.emulsified water, nwater that is suspended in insulatingliquid as clusters of water molecules. It usually givesinsulating liquid a milky appearance.ester-based insulating liquid, nan insulating liquid that maybe either synthetic or natural-based. Synthetic ester liquidsare produced by th
