1、Designation: D150 18Standard Test Methods forAC Loss Characteristics and Permittivity (DielectricConstant) of Solid Electrical Insulation1This standard is issued under the fixed designation D150; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 These t
3、est methods cover the determination of relativepermittivity, dissipation factor, loss index, power factor, phaseangle, and loss angle of specimens of solid electrical insulatingmaterials when the standards used are lumped impedances. Thefrequency range addressed extends from less than 1 Hz toseveral
4、 hundred megahertz.NOTE 1In common usage, the word relative is frequently dropped.1.2 These test methods provide general information on avariety of electrodes, apparatus, and measurement techniques.Areader interested in issues associated with a specific materialneeds to consult ASTM standards or oth
5、er documents directlyapplicable to the material to be tested.2,31.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and det
6、er-mine the applicability of regulatory limitations prior to use.For specific hazard statements, see 10.2.1.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of Inte
7、rnational Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:4D374 Test Methods for Thickness of Solid Electrical Insu-lation (Metric) D0374_D0374MD618 Practice for Conditioning Plastics f
8、or TestingD1531 Test Methods for Relative Permittivity (DielectricConstant) and Dissipation Factor by Fluid DisplacementProcedures (Withdrawn 2012)5D1711 Terminology Relating to Electrical InsulationD5032 Practice for Maintaining Constant Relative Humidityby Means of Aqueous Glycerin SolutionsE104 P
9、ractice for Maintaining Constant Relative Humidityby Means of Aqueous Solutions3. Terminology3.1 Definitions:3.1.1 Use Terminology D1711 for definitions of terms usedin these test methods and associated with electrical insulationmaterials.3.2 Definitions of Terms Specific to This Standard:3.2.1 capa
10、citance, C, nthat property of a system ofconductors and dielectrics which permits the storage of elec-trically separated charges when potential differences existbetween the conductors.3.2.1.1 DiscussionCapacitance is the ratio of a quantity, q,of electricity to a potential difference, V.Acapacitance
11、 value isalways positive. The units are farads when the charge isexpressed in coulombs and the potential in volts:C 5 q/V (1)3.2.2 dissipation factor, (D), (loss tangent), (tan ), ntheratio of the loss index (“) to the relative permittivity () whichis equal to the tangent of its loss angle () or the
12、 cotangent ofits phase angle () (see Fig. 1 and Fig. 2).D 5 “/ (2)1These test methods are under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and are the direct responsibility ofSubcommittee D09.12 on Electrical Tests.Current edition approved May 1, 2018. Pu
13、blished May 2018. Originallyapproved in 1922. Last previous edition approved in 2011 as D150 11. DOI:10.1520/D0150-18.2R. Bartnikas, Chapter 2, “Alternating-Current Loss and PermittivityMeasurements,” Engineering Dielectrics, Vol. IIB, Electrical Properties of SolidInsulating Materials, Measurement
14、Techniques, R. Bartnikas, Editor, STP 926,ASTM, Philadelphia, 1987.3R. Bartnikas, Chapter 1, “Dielectric Loss in Solids,” Engineering Dielectrics,Vol IIA, Electrical Properties of Solid Insulating Materials: Molecular Structure andElectrical Behavior, R. Bartnikas and R. M. Eichorn, Editors, STP 783
15、, ASTMPhiladelphia, 1983.4For 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.5The last approved version of this h
16、istorical 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 established in the De
17、cision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.2.1 Discussiona:D 5 tan 5 cot 5 Xp/Rp5 G/Cp5 1/CpRp(3)where:G = equivalent ac conductance,Xp= parallel reactance,Rp=
18、equivalent ac parallel resistance,Cp= parallel capacitance, and =2f (sinusoidal wave shape assumed).The reciprocal of the dissipation factor is the quality factor,Q, sometimes called the storage factor. The dissipation factor,D, of the capacitor is the same for both the series and parallelrepresenta
19、tions as follows:D 5 RsCs5 1/RpCp(4)The relationships between series and parallel componentsare as follows:Cp5 Cs/11D2! (5)Rp/Rs5 11D2!/D25 111/D2! 5 11Q2(6)3.2.2.2 Discussionb: Series RepresentationWhile theparallel representation of an insulating material having adielectric loss (Fig. 3) is usuall
20、y the proper representation, it isalways possible and occasionally desirable to represent acapacitor at a single frequency by a capacitance, Cs, in serieswith a resistance, Rs(Fig. 4 and Fig. 2).3.2.3 loss angle (phase defect angle), (), nthe anglewhose tangent is the dissipation factor or arctan “/
21、 or whosecotangent is the phase angle.3.2.3.1 DiscussionThe relation of phase angle and lossangle is shown in Fig. 1 and Fig. 2. Loss angle is sometimescalled the phase defect angle.3.2.4 loss index, “ (r“),nthe magnitude of the imagi-nary part of the relative complex permittivity; it is the product
22、of the relative permittivity and dissipation factor.3.2.4.1 DiscussionaIt is expressed as:“ 5 D (7)5power loss/E23f 3volume 3constant!When the power loss is in watts, the applied voltage is involts per centimeter, the frequency is in hertz, the volume isthe cubic centimeters to which the voltage is
23、applied, theconstant has the value of 5.556 1013.3.2.4.2 DiscussionbLoss index is the term agreed uponinternationally. In the U.S.A. “ was formerly called the lossfactor.3.2.5 phase angle, ,nthe angle whose cotangent is thedissipation factor, arccot “/ and is also the angular differencein the phase
24、between the sinusoidal alternating voltage appliedto a dielectric and the component of the resulting currenthaving the same frequency as the voltage.3.2.5.1 DiscussionThe relation of phase angle and lossangle is shown in Fig. 1 and Fig. 2. Loss angle is sometimescalled the phase defect angle.3.2.6 p
25、ower factor, PF, nthe ratio of the power in watts,W, dissipated in a material to the product of the effectivesinusoidal voltage, V, and current, I, in volt-amperes.3.2.6.1 DiscussionPower factor is expressed as the cosineof the phase angle (or the sine of the loss angle ).PF 5 W/VI 5 G/=G21Cp!25 sin
26、 5 cos (8)When the dissipation factor is less than 0.1, the powerfactor differs from the dissipation factor by less than 0.5 %.Their exact relationship is found from the following:PF 5 D/=11D2(9)D 5 PF/=1 2 PF!23.2.7 relative permittivity (relative dielectric constant) (SIC)(r), nthe real part of th
27、e relative complex permittivity. It isalso the ratio of the equivalent parallel capacitance, Cp,ofagiven configuration of electrodes with a material as a dielectricto the capacitance, C, of the same configuration of electrodeswith vacuum (or air for most practical purposes) as thedielectric:FIG. 1 V
28、ector Diagram for Parallel CircuitFIG. 2 Vector Diagram for Series CircuitFIG. 3 Parallel CircuitFIG. 4 Series CircuitD150 182 5 Cp/Cv(10)3.2.7.1 DiscussionaIn common usage the word “rela-tive” is frequently dropped.3.2.7.2 DiscussionbExperimentally, vacuum must bereplaced by the material at all poi
29、nts where it makes asignificant change in capacitance. The equivalent circuit of thedielectric is assumed to consist of Cp, a capacitance in parallelwith conductance. (See Fig. 3.)3.2.7.3 DiscussioncCxis taken to be Cp, the equivalentparallel capacitance as shown in Fig. 3.3.2.7.4 DiscussiondThe ser
30、ies capacitance is largerthan the parallel capacitance by less than 1 % for a dissipationfactor of 0.1, and by less than 0.1 % for a dissipation factor of0.03. If a measuring circuit yields results in terms of seriescomponents, the parallel capacitance must be calculated fromEq 5 before the correcti
31、ons and permittivity are calculated.3.2.7.5 DiscussioneThe permittivity of dry air at 23Cand standard pressure at 101.3 kPa is 1.000536 (1).6Itsdivergence from unity, 1, is inversely proportional toabsolute temperature and directly proportional to atmosphericpressure. The increase in permittivity wh
32、en the space issaturated with water vapor at 23C is 0.00025 (2, 3), and variesapproximately linearly with temperature expressed in degreesCelsius, from 10 to 27C. For partial saturation the increase isproportional to the relative humidity4. Summary of Test Method4.1 Capacitance and ac resistance mea
33、surements are madeon a specimen. Relative permittivity is the specimen capaci-tance divided by a calculated value for the vacuum capacitance(for the same electrode configuration), and is significantlydependent on resolution of error sources. Dissipation factor,generally independent of the specimen g
34、eometry, is alsocalculated from the measured values.4.2 This method provides (1) guidance for choices ofelectrodes, apparatus, and measurement approaches; and (2)directions on how to avoid or correct for capacitance errors.4.2.1 General Measurement Considerations:Fringing and Stray Capacitance Guard
35、ed ElectrodesGeometry of Specimens Calculation of Vacuum CapacitanceEdge, Ground, and Gap Corrections4.2.2 Electrode Systems - Contacting ElectrodesElectrode Materials Metal FoilConducting Paint Fired-On SilverSprayed Metal Evaporated MetalLiquid Metal Rigid MetalWater4.2.3 Electrode Systems - Non-C
36、ontacting ElectrodesFixed Electrodes Micrometer ElectrodesFluid Displacement Methods4.2.4 Choice of Apparatus and Methods for MeasuringCapacitance and AC LossFrequency Direct and Substitution MethodsTwo-Terminal Measurements Three-Terminal MeasurementsFluid Displacement Methods Accuracy consideratio
37、ns5. Significance and Use5.1 PermittivityInsulating materials are used in general intwo distinct ways, (1) to support and insulate components of anelectrical network from each other and from ground, and (2)tofunction as the dielectric of a capacitor. For the first use, it isgenerally desirable to ha
38、ve the capacitance of the support assmall as possible, consistent with acceptable mechanical,chemical, and heat-resisting properties. A low value of permit-tivity is thus desirable. For the second use, it is desirable tohave a high value of permittivity, so that the capacitor is ableto be physically
39、 as small as possible. Intermediate values ofpermittivity are sometimes used for grading stresses at the edgeor end of a conductor to minimize ac corona. Factors affectingpermittivity are discussed in Appendix X3.5.2 AC LossFor both cases (as electrical insulation and ascapacitor dielectric) the ac
40、loss generally needs to be small,both in order to reduce the heating of the material and tominimize its effect on the rest of the network. In highfrequency applications, a low value of loss index is particularlydesirable, since for a given value of loss index, the dielectricloss increases directly w
41、ith frequency. In certain dielectricconfigurations such as are used in terminating bushings andcables for test, an increased loss, usually obtained fromincreased conductivity, is sometimes introduced to control thevoltage gradient. In comparisons of materials having approxi-mately the same permittiv
42、ity or in the use of any material undersuch conditions that its permittivity remains essentiallyconstant, it is potentially useful to consider also dissipationfactor, power factor, phase angle, or loss angle. Factorsaffecting ac loss are discussed in Appendix X3.5.3 CorrelationWhen adequate correlat
43、ing data areavailable, dissipation factor or power factor are useful toindicate the characteristics of a material in other respects suchas dielectric breakdown, moisture content, degree of cure, anddeterioration from any cause. However, it is possible thatdeterioration due to thermal aging will not
44、affect dissipationfactor unless the material is subsequently exposed to moisture.While the initial value of dissipation factor is important, thechange in dissipation factor with aging is often much moresignificant.6. General Measurement Considerations6.1 Fringing and Stray CapacitanceThese test meth
45、odsare based upon measuring the specimen capacitance betweenelectrodes, and measuring or calculating the vacuum capaci-tance (or air capacitance for most practical purposes) in thesame electrode system. For unguarded two-electrodemeasurements, the determination of these two values requiredto compute
46、 the permittivity, x is complicated by the presenceof undesired fringing and stray capacitances which get in-cluded in the measurement readings. Fringing and stray capaci-tances are illustrated by Figs. 5 and 6 for the case of twounguarded parallel plate electrodes between which the speci-men is to
47、be placed for measurement. In addition to the desireddirect interelectrode capacitance, Cv, the system as seen atterminals a-a includes the following:6The boldface numbers in parentheses refer to the list of references appended tothese test methods.D150 183Ce= fringing or edge capacitance,Cg= capaci
48、tance to ground of the outside face of eachelectrode,CL= capacitance between connecting leads,CLg= capacitance of the leads to ground, andCLe= capacitance between the leads and the electrodes.Only the desired capacitance, Cv, is independent of theoutside environment, all the others being dependent t
49、o a degreeon the proximity of other objects. It is necessary to distinguishbetween two possible measuring conditions to determine theeffects of the undesired capacitances. When one measuringelectrode is grounded, as is often the case, all of the capaci-tances described are in parallel with the desired Cv- with theexception of the ground capacitance of the grounded electrodeand its lead. If Cvis placed within a chamber with walls atguard potential, and the leads to the chamber are gu
