1、Designation: D150 11Standard 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. Scope*1.1 These
3、test 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 tosevera
4、l 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 ot
5、her 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 and health practices and determine the appl
6、ica-bility of regulatory limitations prior to use. For specific hazardstatements, see 7.2.6.1 and 10.2.1.2. Referenced Documents2.1 ASTM Standards:4D374 Test Methods for Thickness of Solid Electrical Insu-lation (Metric) D0374_D0374MD618 Practice for Conditioning Plastics for TestingD1082 Test Metho
7、d for Dissipation Factor and Permittivity(Dielectric Constant) of MicaD1531 Test Methods for Relative Permittivity (DielectricConstant) and Dissipation Factor by Fluid DisplacementProcedures (Withdrawn 2012)5D1711 Terminology Relating to Electrical InsulationD5032 Practice for Maintaining Constant R
8、elative Humidityby Means of Aqueous Glycerin SolutionsE104 Practice for Maintaining Constant Relative Humidityby Means of Aqueous SolutionsE197 Specification for Enclosures and Servicing Units forTests Above and Below Room Temperature (Withdrawn1981)53. Terminology3.1 Definitions:3.1.1 Use Terminolo
9、gy 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 capacitance, C, nthat property of a system ofconductors and dielectrics which permits the storage of elec-trically separated charges
10、 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 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
11、.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 cotangent ofits phase angle () (see Fig. 1 and Fig. 2).D 5 “/ (2)3.2.2.1 Discussiona:D 5 tan 5 cot 5 Xp/Rp5 G/Cp5 1/CpRp(3)1The
12、se 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 Aug. 1, 2011. Published August 2011. Originallyapproved in 1922. Last previous editio
13、n approved in 2004 as D150 98 (2004).DOI: 10.1520/D0150-11.2R. Bartnikas, Chapter 2, “Alternating-Current Loss and PermittivityMeasurements,” Engineering Dielectrics, Vol. IIB, Electrical Properties of SolidInsulating Materials, Measurement Techniques, R. Bartnikas, Editor, STP 926,ASTM, Philadelphi
14、a, 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, ASTMPhiladelphia, 1983.4For referenced ASTM standards, vi
15、sit 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 historical standard is referenced onwww.astm.org.*A Summary
16、of Changes section appears at the end of this standardCopyright 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
17、the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1where:G = equivalent ac conductance,Xp= parallel reactance,Rp= equivalent ac parallel resistance,Cp= parallel capac
18、itance, 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 parallelrepresentations as follows:D 5 RsCs5 1/RpCp(4)The relationship
19、s 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 usually the proper representation, it isalways possible an
20、d 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 “/ or whosecotangent is the phase angle.3.2.3.1 Discus
21、sionThe 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 productof the relative permittivity and dissipation factor.
22、3.2.4.1 DiscussionaIt may be expressed as:“ 5 D (7)5power loss/E23f 3volume 3constant!When the power loss is in watts, the applied voltage is involts per centimetre, the frequency is in hertz, the volume isthe cubic centimetres to which the voltage is applied, theconstant has the value of 5.556 1013
23、.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 between the sinusoidal alternating voltage appli
24、edto 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 power factor, PF, nthe ratio of the power in watt
25、s,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 may be expressed as thecosine of the phase angle (or the sine of the loss angle ).PF 5 W/VI 5 G/=G21Cp!25 sin 5 cos (8)When the dissipation factor is les
26、s than 0.1, the powerfactor differs from the dissipation factor by less than 0.5 %.Their exact relationship may be 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 the relative complex permittivity. It isal
27、so 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: 5 Cp/Cv(10)3.2.7.1 DiscussionaIn common usage t
28、he word “rela-tive” is frequently dropped.FIG. 1 Vector Diagram for Parallel CircuitFIG. 2 Vector Diagram for Series CircuitFIG. 3 Parallel CircuitFIG. 4 Series CircuitD150 1123.2.7.2 DiscussionbExperimentally, vacuum must bereplaced by the material at all points where it makes asignificant change i
29、n 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 series capacitance is largerthan the parall
30、el 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 corrections and permittivity are calculated.3.2.
31、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 when the space issaturated with water vapo
32、r 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 measurements are madeon a specimen. Relativ
33、e 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 geometry, is alsocalculated from the meas
34、ured 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 Guarded ElectrodesGeometry of Specimens Calcu
35、lation 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-Contacting ElectrodesFixed Electrodes Mic
36、rometer 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 considerations5. Significance and Use5.1 Permittivit
37、yInsulating 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 have the capacitance of the support assmal
38、l 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 as small as possible. Intermediate valu
39、es 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 loss generally needs to be small,both in
40、 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 with frequency. In certain dielectricconf
41、igurations 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 permittivity or in the use of any material unders
42、uch 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 correlating data areavailable, dissipation facto
43、r 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 affect dissipationfactor unless the mate
44、rial 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 methodsare based upon measuring the specimen
45、 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 the permittivity, x is complicated by t
46、he 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 be placed for measurement. In addition t
47、o 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 113Ce= fringing or edge capacitance,Cg= capacitance to ground of the outside face of e
48、achelectrode,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 to a degreeon the proximity of other obje
49、cts. 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 guarded, thecapacitance to ground no longe
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