1、Designation: D2864 10Standard 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 nu
2、mber 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 as
3、 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 f
5、or 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 DistillateFuels3E355 Practice for Gas Chromatography Terms and Rela-tionships2. Terminologyac
6、symbol 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 occurring in one secondis called the F
7、REQUENCY, 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 treatinga refining process in which an unfinishedpetroleum insulating oil is contacted with sulf
8、uric acid toimprove its color, odor, stability, and other properties.ac loss characteristicsthose 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 losses that would result from the use of such
9、material in an ac electric field.additivea chemical compound or compounds added to aninsulating fluid for the purpose of imparting new propertiesor altering those properties which the fluid already has.ambient temperaturethe temperature of the surroundingatmosphere as determined by an instrument shi
10、elded fromdirect or reflected rays of the sun.aniline pointthe minimum temperature for complete misci-bility of equal volumes of aniline and the sample under test.See Test Methods D611. In comparing two samples ofsimilar molecular weight, the aniline point can be used as ameans of comparing aromatic
11、 content of the two samples. Aproduct of high aniline point will be low in aromatics andnaphthenes, and therefore high in paraffins.API gravityan arbitrary scale developed by the AmericanPetroleum Institute and frequently used in reference topetroleum insulating oil. The relationship between APIgrav
12、ity 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 Liquids and Gases and is the direct responsibility of Subcom-mittee D27.15 on Planning Resource and D
13、evelopment.Current edition approved May 15, 2010. Published June 2010. Originallyapproved in 1970. Last previous edition approved in 2007 as D2864 07. DOI:10.1520/D2864-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For An
14、nual 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.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428
15、-2959, United States.aromaticsthat class of organic compounds which behavechemically like benzene. They are cyclic unsaturated organiccompounds that can sustain an induced electronic ringcurrent due to delocalization of electrons around the ring.DISCUSSIONEmpirically, the aromatic portion of a miner
16、al insulat-ing oil can be estimated by correlation with physical properties (SeeTest Method D2140), or by selective adsorption on clay-gel (See TestMethod D2007).askarela generic term for a group of synthetic, fire-resistant,chlorinated aromatic hydrocarbons used as electrical insu-lating liquids. T
17、hey have a property under arcing conditionssuch that any gases produced will consist predominantly ofnoncombustible hydrogen chloride with lesser amounts ofcombustible gases.atomic absorptionthe absorption of radiant energy byground state atoms. Substances when dispersed as an atomicvapor will absor
18、b characteristic radiations identical to thosewhich the same substances can emit. This property is thebasis for analysis by atomic absorption spectroscopy.capacitivitythe same as permittivity, relative.colora quality of visible phenomena of insulating fluids, thenumerical value for which is derived
19、by comparing thisquality using transmitted light with that of a series ofnumbered reference bustible gasesflammable gases formed from breakdown(partial or complete) of some insulating materials subjectedto electrical or thermal stress, or both.conductancethe ratio of the current carried through amat
20、erial 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 conductance dc and conductance ac.DISCUSSION2For dielectrics the conductance may be dependenton
21、 the electrification time.conductance, apparent dcthe dc conductance measured atthe end of a specific electrification time. The “apparent dcconductance” is the reciprocal of the “apparent dc resis-tance.” The unit is: (ohm)1or siemens.DISCUSSIONThe term “apparent dc conductance” is used to distin-gu
22、ish 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 thesteady-state current is reached in a fraction of a second.conductance, dcthe ratio of the
23、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 the“dc resistance.” The unit is: (ohm)1or siemens.conductivitythe ratio of the current density
24、 carried througha specimen to the potential gradient paralleling the current.This is numerically equal to the conductance betweenopposite faces of a unit cube of liquid. It is the reciprocal ofresistivity.DISCUSSION1Conductivity is a general term. Specific referencemay be made to conductivity, dc.DI
25、SCUSSION2For dielectrics the conductivity may be dependenton the electrification time. (See also conductivity, apparent dcvolume and conductivity, dc volume.)conductivity, apparent dc volumethe “dc volume conduc-tivity” measured at the end of a specified electrification time.It is the reciprocal of
26、the apparent dc volume resistivity. Theunit most commonly used is: (ohm-centimetre)1or siemensper centimetre. The SI unit is (ohm-metre)1.conductivity, dcthe ratio of the current density passingthrough a specimen at a given instant of time and underprescribed conditions, to the dc potential gradient
27、 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 cube of liquid. The unit is: (ohm-centimetre)1orsiemens per centimetre. The SI unit is: (ohm-metre)1.DISCUS
28、SIONThe “dc conductivity” may contain components of bothsurface conductance and volume conductance, but, in general, surfaceeffects are not common in measurements on fluid dielectrics. Theproperty most commonly measured is either the “dc volume conduc-tivity” or the “apparent dc volume conductivity.
29、”conductivity, dc volumethe 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 steady direct voltage gradient parallel with thecurrent in the material. The dc volume conductivity is thereciproca
30、l 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 required forthe steady-state current to be reached may be very long; from severalminutes to several months may be re
31、quired.coronaa luminous discharge due to ionization of the airsurrounding an electrode, caused by the high electric fieldstrength in the vicinity of the electrode, exceeding a certaincritical (that is, threshold) value.corona effectlight emitted in the UV range of the electro-magnetic spectrum by el
32、ectronically excited molecules thathave reached a singlet state and have not consumed theabsorbed energy by other physical process.corona (partial discharge) inception voltage, CIVthe low-est voltage at which continuous partial discharge (or corona)exceeding a specified intensity is observed as the
33、appliedvoltage is gradually increased. Where the applied voltage isalternating, the CIV is expressed as 1/=2 of the peakvoltage.corona (partial discharge) extinction voltage, CEVthehighest voltage at which partial discharge (or corona) nolonger exceeds a specified intensity as the applied voltage is
34、gradually decreased from a value above the corona inceptionvoltage. Where the applied voltage is alternating the CEV isexpressed as 1/=2 of the peak voltage.D2864 102corrosive sulfurn, elemental sulfur and thermally unstablesulfur compounds in electrical insulating oil that can causecorrosion of cer
35、tain transformer metals such as copper andsilver.dcsymbol used to designate an electric voltage or currentwhose amplitude does not vary periodically 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 dy
36、namos and rectifiers, whose amplitude isnot strictly time-invariant.dew-point temperaturethe temperature (above 0C) towhich a gas or vapor must be cooled at constant pressure andconstant water-vapor composition in order for saturation tooccur.DISCUSSIONAt temperatures below 0C, vapor may first be no
37、ticedin 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 vapor systems in which saturation with respect toa substance other than water vapor can occur.dielectrica medium in which it is po
38、ssible to maintain anelectric field with little supply of energy from outsidesources. The energy required to produce the electric field isrecoverable, in whole or in part. A vacuum, as well as anyinsulating material is a dielectric.dielectric breakdown voltagethe potential difference atwhich electri
39、cal failure occurs in an electrical insulatingmaterial or insulation structure, under prescribed test condi-tions.dielectric constant See dielectric constant, relative (espe-cially Note 2). (See also permittivity (especially Note 2).)dielectric constant, absolutethe same as permittivity.dielectric c
40、onstant, relativethe same as permittivity, rela-tive.DISCUSSION1Current practice including international usage is toprefer the term relative permittivity.DISCUSSION2Common usage has been to drop the term “relative”and simply use dielectric constant when the dimensionless ratio is thequantity being r
41、eferred to.dielectric failurethe failure of an element in a dielectriccircuit that exists when the insulating element becomesconducting. 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 transferac
42、companied by collapse of the insulating properties andpartial of complete localized destruction of the dielectricmedium. In the case of liquids and gases the failure may beself-healing.dielectric strengtha property of an insulating materialdescribed by the average voltage gradient at which electricb
43、reakdown occurs under specific conditions of test.dissipation factor, Dthe ratio of the loss index to its relativepermittivity 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 equa
44、tion:D 5 PF/=1 2 PF !2DISCUSSIONIt may be expressed as D = tan d = cotan u =G/vCp5 1/vCpRp5vRsCswhere G is the equivalent parallel ac conductance, Cpis the parallelcapacitance, Rpis the equivalent parallel ac resistance, Csis the seriescapacitance, and Rsis the equivalent series resistance.dissipati
45、on factor, dielectricsame as dissipation factor.dissolved waterwater that is in solution interspersed be-tween molecules of insulating liquid.electric constant the same as permittivity of free space.electric creepage strengththe average voltage gradientunder specific conditions of test and for a spe
46、cific electrodeconfiguration, at which dielectric failure occurs along theinterface between a solid insulating 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 fai
47、lure may result intracking.electrical dischargea discontinuous movement of electricalcharges through an insulating medium, initiated by electronavalanches and supplemented by secondary processes.electrification timethe time during which a steady directpotential is applied to electrical insulating ma
48、terials beforethe current is measured.emulsified waterwater that is suspended in insulating liquidas clusters of water molecules. It usually gives insulatingliquid a milky appearance.ester-based insulating fluidan insulating fluid that may beeither synthetic or natural-based. Synthetic ester fluids
49、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 acids of varyingmolecular weights.fire pointthe lowest temperature at which a specimen willsustain burning for 5 s under specified conditions of test.flash pointthe lowest temperature corrected to a barometr
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