1、Designation: D2864 101Standard 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.1NOTEThe part of speech was added editorially to the terms in January 2012.INTRODUCTIONThe definitions contained in this terminology pertain to term
3、s as they are used in conjunction withfluid insulating materials. Insofar as 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
4、Test Methods for Aniline Point and Mixed AnilinePoint of Petroleum Products 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 Carb
5、on-Type Compositionof Insulating Oils of Petroleum OriginD2300 Test Method for Gassing of Electrical InsulatingLiquids Under Electrical Stress and Ionization (ModifiedPirelli Method)D2500 Test Method for Cloud Point of Petroleum ProductsD3117 Test Method for Wax Appearance Point of DistillateFuels3E
6、355 Practice for Gas Chromatography Terms and Rela-tionships2. 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 referre
7、d to as aCYCLE, and the number of cycles occurring 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 refi
8、ning process in which an unfinishedpetroleum 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
9、used as a measure of the poweror energy losses 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 te
10、mperature, nthe temperature of the surroundingatmosphere 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 sampl
11、es ofsimilar molecular weight, the aniline 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 Institut
12、e and frequently used in reference topetroleum 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!2131.51This terminology is under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquid
13、s and Gases and is the direct responsibility of Subcom-mittee D27.15 on Planning Resource and Development.Current edition approved May 15, 2010. Published June 2010. Originallyapproved in 1970. Last previous edition approved in 2010 as D2864 10. DOI:10.1520/D2864-10E01.2For referenced ASTM standards
14、, 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.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.
15、org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.aromatics, nthat class of organic compounds which behavechemically like benzene. They are cyclic unsaturated organiccompounds that can sustain an induced electronic ringcurrent due
16、to delocalization of electrons around 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
17、of synthetic, fire-resistant, chlorinated 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,
18、nthe absorption of radiant energy byground 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 permitti
19、vity, relative.color, na quality of 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 insula
20、ting materialssubjected to electrical 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. Spec
21、ific referencemay be made to conductance 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
22、 the “apparent dc resis-tance.” The 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 f
23、ound in metallic conductors where thesteady-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 “d
24、c conductance” is the reciprocal of 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 liq
25、uid. It is thereciprocal of resistivity.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.)conduct
26、ivity, apparent dc volume, nthe “dc 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
27、 ratio of the current density passingthrough 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” betw
28、een opposite faces of a centi-metre 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 measure
29、ments on fluid dielectrics. Theproperty 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 stea
30、dy-state currentdensity to the steady 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
31、insulating materials the time required 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 th
32、e electrode, exceeding a certaincritical (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 d
33、ischarge) inception voltage, CIV, nthelowest 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/=2ofthepeak voltage.corona (partial disch
34、arge) extinction voltage, CEV, nthehighest voltage at which partial discharge (or corona) nolonger exceeds a specified intensity as the applied voltage isgradually decreased from a value above the corona inceptionD2864 1012voltage. Where the applied voltage is alternating the CEV isexpressed as 1/=2
35、 of the peak voltage.corrosive sulfur, nelemental sulfur and thermally unstablesulfur compounds in electrical insulating oil that can causecorrosion of certain transformer metals such as copper andsilver.dc, nsymbol used to designate an electric voltage or currentwhose amplitude does not vary period
36、ically with respect totime, as for 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
37、must be cooled at constant pressure 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 temperatu
38、res alsoexist for other gas or vapor 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
39、isrecoverable, in whole or in part. 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
40、, n See dielectric constant, relative(especially Note 2). (See also permittivity (especially Note2).)dielectric constant, absolute, nthe same as permittivity.dielectric constant, relative, nthe same as permittivity,relative.DISCUSSION1Current practice including international usage is toprefer the te
41、rm relative permittivity.DISCUSSION2Common 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 becomesc
42、onducting. This event may take 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 th
43、e case of liquids and gases the 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 permit
44、tivity orD 5k9/k8It is also the tangent of its loss angle, d, or the cotangent ofits phase angle, u. The dissipation factor is related to the powerfactor, PF, by the following equation:D 5 PF/=1 2 PF !2DISCUSSIONIt may be expressed as D = tan d = cotan u =G/vCp5 1/vCpRp5vRsCswhere G is the equivalen
45、t parallel ac conductance, Cpis the parallelcapacitance, Rpis the equivalent parallel ac resistance, Csis the seriescapacitance, and Rsis the equivalent series resistance.dissipation factor, dielectric, nsame as dissipation factor.dissolved water, nwater that is in solution interspersedbetween molec
46、ules of insulating liquid.electric constant, 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
47、 material and the fluid inwhich it is 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 i
48、nsulating medium, initiated byelectron 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
49、as clusters of water molecules. It usually givesinsulating liquid a milky appearance.ester-based insulating fluid, nan insulating fluid that maybe either synthetic or natural-based. Synthetic ester fluids areproduced by the reaction of an organic acid with an alcohol,usually a diol, triol, or tetraol. Natural ester fluids are derivedfrom an animal or agricultural (vegetable or seed) source.They are generically referred to as triglycerides, being acombination of glycerol and various organic
