ASTM D150-2018 Standard Test Methods for AC Loss Characteristics and Permittivity (Dielectric Constant) of Solid Electrical Insulation.pdf

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1、Designation: D150 11D150 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 th

2、e case 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*Sco

3、pe1.1 These test methods cover the determination of relative permittivity, dissipation factor, loss index, power factor, phase angle,and loss angle of specimens of solid electrical insulating materials when the standards used are lumped impedances. The frequencyrange addressed extends from less than

4、 1 Hz to several hundred megahertz.NOTE 1In common usage, the word relative is frequently dropped.1.2 These test methods provide general information on a variety of electrodes, apparatus, and measurement techniques.Areaderinterested in issues associated with a specific material needs to consult ASTM

5、 standards or other documents directly applicableto the material to be tested.2,31.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthe

6、nvironmental practices and determine theapplicability of regulatory limitations prior to use. For specific hazard statements, see 7.2.6.1 and 10.2.1.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on

7、 Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:4D374 Test Methods for Thickness of Solid Electrical Insulation (Metric) D0374_D0374MD618

8、 Practice for Conditioning Plastics for TestingD1082 Test Method for Dissipation Factor and Permittivity (Dielectric Constant) of MicaD1531 Test Methods for Relative Permittivity (Dielectric Constant) and Dissipation Factor by Fluid Displacement Procedures(Withdrawn 2012)5D1711 Terminology Relating

9、to Electrical InsulationD5032 Practice for Maintaining Constant Relative Humidity by Means of Aqueous Glycerin SolutionsE104 Practice for Maintaining Constant Relative Humidity by Means of Aqueous SolutionsE197 Specification for Enclosures and Servicing Units for Tests Above and Below Room Temperatu

10、re (Withdrawn 1981)53. Terminology3.1 Definitions:3.1.1 Use Terminology D1711 for definitions of terms used in these test methods and associated with electrical insulationmaterials.1 These test methods are under the jurisdiction ofASTM Committee D09 on Electrical and Electronic Insulating Materials

11、and are the direct responsibility of SubcommitteeD09.12 on Electrical Tests.Current edition approved Aug. 1, 2011May 1, 2018. Published August 2011May 2018. Originally approved in 1922. Last previous edition approved in 20042011 asD150 98 (2004).D150 11. DOI: 10.1520/D0150-11.10.1520/D0150-18.2 R. B

12、artnikas, Chapter 2, “Alternating-Current Loss and Permittivity Measurements,” Engineering Dielectrics, Vol. IIB, Electrical Properties of Solid Insulating Materials,Measurement Techniques, R. Bartnikas, Editor, STP 926, ASTM, Philadelphia, 1987.3 R. Bartnikas, Chapter 1, “Dielectric Loss in Solids,

13、” Engineering Dielectrics, Vol IIA, Electrical Properties of Solid Insulating Materials: Molecular Structure andElectrical Behavior, R. Bartnikas and R. M. Eichorn, Editors, STP 783, ASTM Philadelphia, 1983.4 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer

14、Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.5 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provid

15、e the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the st

16、andard as published by ASTM is to be considered the official document.*A Summary 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 States13.2 Definitions of Terms Specific to This Standard:

17、3.2.1 capacitance, C, nthat property of a system of conductors and dielectrics which permits the storage of electricallyseparated charges when potential differences exist between the conductors.3.2.1.1 DiscussionCapacitance is the ratio of a quantity, q, of electricity to a potential difference, V.A

18、capacitance value is always positive. The unitsare farads when the charge is expressed in coulombs and the potential in volts:C 5q/V (1)3.2.2 dissipation factor, (D), (loss tangent), (tan ), nthe ratio of the loss index (“) to the relative permittivity () which isequal to the tangent of its loss ang

19、le () or the cotangent of its phase angle () (see Fig. 1 and Fig. 2).D 5“/ (2)3.2.2.1 Discussiona:D5tan5cot5Xp/Rp 5G/C p 51/CpRp (3)where:G = equivalent ac conductance,Xp = parallel reactance,Rp = equivalent ac parallel resistance,Cp = parallel capacitance, and = 2pif (sinusoidal wave shape assumed)

20、.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 parallel representations as follows:D 5RsCs 51/R pCp (4)The relationships between series and parallel components are

21、 as follows:Cp 5Cs/11D 2! (5)Rp/Rs 511D 2!/D25111/D2!511Q 2 (6)3.2.2.2 DiscussionFIG. 1 Vector Diagram for Parallel CircuitFIG. 2 Vector Diagram for Series CircuitD150 182b: Series RepresentationWhile the parallel representation of an insulating material having a dielectric loss (Fig. 3) is usually

22、theproper representation, it is always possible and occasionally desirable to represent a capacitor at a single frequency by acapacitance, Cs, in series with a resistance, R s (Fig. 4 and Fig. 2).3.2.3 loss angle (phase defect angle), (), nthe angle whose tangent is the dissipation factor or arctan

23、“/ or whose cotangentis the phase angle.3.2.3.1 DiscussionThe relation of phase angle and loss angle is shown in Fig. 1 and Fig. 2. Loss angle is sometimes called the phase defect angle.3.2.4 loss index, “ (r“) , nthe magnitude of the imaginary part of the relative complex permittivity; it is the pr

24、oduct of therelative permittivity and dissipation factor.3.2.4.1 DiscussionaIt may be is expressed as:“5D (7)5power loss/E 23f 3volume3constant!When the power loss is in watts, the applied voltage is in volts per centimetre,centimeter, the frequency is in hertz, the vol-ume is the cubic centimetresc

25、entimeters to which the voltage is applied, the constant has the value of 5.556 1013.3.2.4.2 DiscussionbLoss index is the term agreed upon internationally. In the U.S.A. “ was formerly called the loss factor.3.2.5 phase angle, , nthe angle whose cotangent is the dissipation factor, arccot “/ and is

26、also the angular difference inthe phase between the sinusoidal alternating voltage applied to a dielectric and the component of the resulting current having thesame frequency as the voltage.3.2.5.1 DiscussionThe relation of phase angle and loss angle is shown in Fig. 1 and Fig. 2. Loss angle is some

27、times called the phase defect angle.3.2.6 power factor, PF,nthe ratio of the power in watts, W, dissipated in a material to the product of the effective sinusoidalvoltage, V, and current, I, in volt-amperes.3.2.6.1 DiscussionPower factor may be is expressed as the cosine of the phase angle (or the s

28、ine of the loss angle ).PF5W/VI5G/=G21Cp!25 sin 5 cos (8)When the dissipation factor is less than 0.1, the power factor differs from the dissipation factor by less than 0.5 %. Theirexact relationship may be is found from the following:FIG. 3 Parallel CircuitFIG. 4 Series CircuitD150 183PF5D/=11D2 (9

29、)D 5PF/=12PF! 23.2.7 relative permittivity (relative dielectric constant) (SIC) (r), nthe real part of the relative complex permittivity. It is alsothe ratio of the equivalent parallel capacitance, Cp, of a given configuration of electrodes with a material as a dielectric to thecapacitance, C, of th

30、e same configuration of electrodes with vacuum (or air for most practical purposes) as the dielectric:5C p/Cv (10)3.2.7.1 DiscussionaIn common usage the word “relative” is frequently dropped.3.2.7.2 DiscussionbExperimentally, vacuum must be replaced by the material at all points where it makes a sig

31、nificant change in capacitance. Theequivalent circuit of the dielectric is assumed to consist of Cp, a capacitance in parallel with conductance. (See Fig. 3.)3.2.7.3 DiscussioncCx is taken to be C p, the equivalent parallel capacitance as shown in Fig. 3.3.2.7.4 DiscussiondThe series capacitance is

32、larger than the parallel capacitance by less than 1 % for a dissipation factor of 0.1, and by less than0.1 % for a dissipation factor of 0.03. If a measuring circuit yields results in terms of series components, the parallel capacitancemust be calculated from Eq 5 before the corrections and permitti

33、vity are calculated.3.2.7.5 DiscussioneThe permittivity of dry air at 23C and standard pressure at 101.3 kPa is 1.000536 (1).6 Its divergence from unity, 1, isinversely proportional to absolute temperature and directly proportional to atmospheric pressure. The increase in permittivity whenthe space

34、is saturated with water vapor at 23C is 0.00025 (2, 3), and varies approximately linearly with temperature expressedin degrees Celsius, from 10 to 27C. For partial saturation the increase is proportional to the relative humidity4. Summary of Test Method4.1 Capacitance and ac resistance measurements

35、are made on a specimen. Relative permittivity is the specimen capacitancedivided by a calculated value for the vacuum capacitance (for the same electrode configuration), and is significantly dependent onresolution of error sources. Dissipation factor, generally independent of the specimen geometry,

36、is also calculated from themeasured values.4.2 This method provides (1) guidance for choices of electrodes, apparatus, and measurement approaches; and (2) directions onhow to avoid or correct for capacitance errors.4.2.1 General Measurement Considerations:Fringing and Stray Capacitance Guarded Elect

37、rodesGeometry 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-Contactin

38、g ElectrodesFixed Electrodes Micrometer ElectrodesFluid Displacement Methods6 The boldface numbers in parentheses refer to the list of references appended to these test methods.D150 1844.2.4 Choice of Apparatus and Methods for Measuring Capacitance and AC LossFrequency Direct and Substitution Method

39、sTwo-Terminal Measurements Three-Terminal MeasurementsFluid Displacement Methods Accuracy considerations5. Significance and Use5.1 PermittivityInsulating materials are used in general in two distinct ways, (1) to support and insulate components of anelectrical network from each other and from ground

40、, and (2) to function as the dielectric of a capacitor. For the first use, it isgenerally desirable to have the capacitance of the support as small as possible, consistent with acceptable mechanical, chemical,and heat-resisting properties. A low value of permittivity is thus desirable. For the secon

41、d use, it is desirable to have a high valueof permittivity, so that the capacitor is able to be physically as small as possible. Intermediate values of permittivity are sometimesused for grading stresses at the edge or end of a conductor to minimize ac corona. Factors affecting permittivity are disc

42、ussed inAppendix X3.5.2 AC LossFor both cases (as electrical insulation and as capacitor dielectric) the ac loss generally needs to be small, bothin order to reduce the heating of the material and to minimize its effect on the rest of the network. In high frequency applications,a low value of loss i

43、ndex is particularly desirable, since for a given value of loss index, the dielectric loss increases directly withfrequency. In certain dielectric configurations such as are used in terminating bushings and cables for test, an increased loss, usuallyobtained from increased conductivity, is sometimes

44、 introduced to control the voltage gradient. In comparisons of materials havingapproximately the same permittivity or in the use of any material under such conditions that its permittivity remains essentiallyconstant, it is potentially useful to consider also dissipation factor, power factor, phase

45、angle, or loss angle. Factors affecting acloss are discussed in Appendix X3.5.3 CorrelationWhen adequate correlating data are available, dissipation factor or power factor are useful to indicate thecharacteristics of a material in other respects such as dielectric breakdown, moisture content, degree

46、 of cure, and deterioration fromany cause. However, it is possible that deterioration due to thermal aging will not affect dissipation factor unless the material issubsequently exposed to moisture. While the initial value of dissipation factor is important, the change in dissipation factor withaging

47、 is often much more significant.6. General Measurement Considerations6.1 Fringing and Stray CapacitanceThese test methods are based upon measuring the specimen capacitance betweenelectrodes, and measuring or calculating the vacuum capacitance (or air capacitance for most practical purposes) in the s

48、ameelectrode system. For unguarded two-electrode measurements, the determination of these two values required to compute thepermittivity, x is complicated by the presence of undesired fringing and stray capacitances which get included in the measurementreadings. Fringing and stray capacitances are i

49、llustrated by Figs. 5 and 6 for the case of two unguarded parallel plate electrodesbetween which the specimen is to be placed for measurement. In addition to the desired direct interelectrode capacitance, Cv, thesystem as seen at terminals a-a includes the following:Ce = fringing or edge capacitance,Cg = capacitance to ground of the outside face of each electrode,CL = capacitance between connecting leads,CLg = capacitance of the leads to ground, andCLe = capacitance between the le