ASTM D149-2009(2013) Standard Test Method for Dielectric Breakdown Voltage and Dielectric Strength of Solid Electrical Insulating Materials at Commercial Power Frequencies《固体电绝缘材料在.pdf

1、Designation: D149 09 (Reapproved 2013) An American National StandardStandard Test Method forDielectric Breakdown Voltage and Dielectric Strength ofSolid Electrical Insulating Materials at Commercial PowerFrequencies1This standard is issued under the fixed designation D149; the number immediately fol

2、lowing the designation indicates the year oforiginal adoption or, in the 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 appr

3、oved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers procedures for the determina-tion of dielectric strength of solid insulating materials atcommercial power frequencies, under specified conditions.2,31.2 Unless otherwise specified, the tests shall be made at 6

4、0Hz. However, this test method is suitable for use at anyfrequency from 25 to 800 Hz. At frequencies above 800 Hz,dielectric heating is a potential problem.1.3 This test method is intended to be used in conjunctionwith any ASTM standard or other document that refers to thistest method. References to

5、 this document need to specify theparticular options to be used (see 5.5).1.4 It is suitable for use at various temperatures, and in anysuitable gaseous or liquid surrounding medium.1.5 This test method is not intended for measuring thedielectric strength of materials that are fluid under the condi-

6、tions of test.1.6 This test method is not intended for use in determiningintrinsic dielectric strength, direct-voltage dielectric strength,or thermal failure under electrical stress (see Test MethodD3151).1.7 This test method is most commonly used to determinethe dielectric breakdown voltage through

7、 the thickness of a testspecimen (puncture). It is also suitable for use to determinedielectric breakdown voltage along the interface between asolid specimen and a gaseous or liquid surrounding medium(flashover). With the addition of instructions modifying Sec-tion 12, this test method is also suita

8、ble for use for prooftesting.1.8 This test method is similar to IEC Publication 243-1.Allprocedures in this method are included in IEC 243-1. Differ-ences between this method and IEC 243-1 are largely editorial.1.9 This standard does not purport to address all of thesafety concerns, if any, associat

9、ed with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific hazardstatements are given in Section 7. Also see 6.4.1.2. Referenced Documents2.1 ASTM Standa

10、rds:4D374 Test Methods for Thickness of Solid Electrical Insu-lation (Withdrawn 2013)5D618 Practice for Conditioning Plastics for TestingD877 Test Method for Dielectric Breakdown Voltage ofInsulating Liquids Using Disk ElectrodesD1711 Terminology Relating to Electrical InsulationD2413 Practice for P

11、reparation of Insulating Paper andBoard Impregnated with a Liquid DielectricD3151 Test Method for Thermal Failure of Solid ElectricalInsulating Materials Under Electric Stress (Withdrawn2007)5D3487 Specification for Mineral Insulating Oil Used inElectrical ApparatusD5423 Specification for Forced-Con

12、vection Laboratory Ov-ens for Evaluation of Electrical Insulation1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.12 on Electrical Tests.Current edition approved April 1, 2013. Publi

13、shed April 2013. Originallyapproved in 1922. Last previous edition approved in 2009 as D149 09. DOI:10.1520/D0149-09R13.2Bartnikas, R., Chapter 3, “High Voltage Measurements,” Electrical Propertiesof Solid Insulating Materials, Measurement Techniques , Vol. IIB, EngineeringDielectrics, R. Bartnikas,

14、 Editor, ASTM STP 926, ASTM, Philadelphia, 1987 .3Nelson, J. K., Chapter 5, “Dielectric Breakdown of Solids,” ElectricalProperties of Solid Insulating Materials: Molecular Structure and ElectricalBehavior, Vol. IIA, Engineering Dielectrics, R. Bartnikas and R. M. Eichorn,Editors, ASTM STP 783, ASTM,

15、 Philadelphia, 19834For 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 histori

16、cal standard is referenced onwww.astm.org.*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 States12.2 IEC Standard:Pub. 243-1 Methods of Test for Electrical Strength of SolidIns

17、ulating MaterialsPart 1: Tests at Power Frequencies62.3 ANSI Standard:C68.1 Techniques for Dielectric Tests, IEEE Standard No.473. Terminology3.1 Definitions:3.1.1 dielectric breakdown voltage (electric breakdownvoltage), nthe potential difference at which dielectric failureoccurs under prescribed c

18、onditions in an electrical insulatingmaterial located between two electrodes. (See also AppendixX1.)3.1.1.1 DiscussionThe term dielectric breakdown voltageis sometimes shortened to “breakdown voltage.”3.1.2 dielectric failure (under test), nan event that isevidenced by an increase in conductance in

19、the dielectric undertest limiting the electric field that can be sustained.3.1.3 dielectric strength, nthe voltage gradient at whichdielectric failure of the insulating material occurs under spe-cific conditions of test.3.1.4 electric strength, nsee dielectric strength.3.1.4.1 DiscussionInternationa

20、lly, “electric strength” isused almost universally.3.1.5 flashover, na disruptive electrical discharge at thesurface of electrical insulation or in the surrounding medium,which may or may not cause permanent damage to theinsulation.3.1.6 For definitions of other terms relating to solid insulat-ing m

21、aterials, refer to Terminology D1711.4. Summary of Test Method4.1 Alternating voltage at a commercial power frequency(60 Hz, unless otherwise specified) is applied to a testspecimen. The voltage is increased from zero or from a levelwell below the breakdown voltage, in one of three prescribedmethods

22、 of voltage application, until dielectric failure of thetest specimen occurs.4.2 Most commonly, the test voltage is applied using simpletest electrodes on opposite faces of specimens. The options forthe specimens are that they be molded or cast, or cut from flatsheet or plate. Other electrode and sp

23、ecimen configurations arealso suitable for use to accommodate the geometry of thesample material, or to simulate a specific application for whichthe material is being evaluated.5. Significance and Use5.1 The dielectric strength of an electrical insulating mate-rial is a property of interest for any

24、application where anelectrical field will be present. In many cases the dielectricstrength of a material will be the determining factor in thedesign of the apparatus in which it is to be used.5.2 Tests made as specified herein are suitable for use toprovide part of the information needed for determi

25、ning suit-ability of a material for a given application; and also, fordetecting changes or deviations from normal characteristicsresulting from processing variables, aging conditions, or othermanufacturing or environmental situations. This test method isuseful for process control, acceptance or rese

26、arch testing.5.3 Results obtained by this test method can seldom be useddirectly to determine the dielectric behavior of a material in anactual application. In most cases it is necessary that theseresults be evaluated by comparison with results obtained fromother functional tests or from tests on ot

27、her materials, or both,in order to estimate their significance for a particular material.5.4 Three methods for voltage application are specified inSection 12: Method A, Short-Time Test; Method B, Step-by-Step Test; and Method C, Slow Rate-of-Rise Test. MethodAisthe most commonly-used test for qualit

28、y-control tests.However, the longer-time tests, Methods B and C, whichusually will give lower test results, will potentially give moremeaningful results when different materials are being com-pared with each other. If a test set with motor-driven voltagecontrol is available, the slow rate-of-rise te

29、st is simpler andpreferable to the step-by-step test. The results obtained fromMethods B and C are comparable to each other.5.5 Documents specifying the use of this test method shallalso specify:5.5.1 Method of voltage application,5.5.2 Voltage rate-of-rise, if slow rate-of-rise method isspecified,5

30、.5.3 Specimen selection, preparation, and conditioning,5.5.4 Surrounding medium and temperature during test,5.5.5 Electrodes,5.5.6 Wherever possible, the failure criterion of the current-sensing element, and5.5.7 Any desired deviations from the recommended proce-dures as given.5.6 If any of the requ

31、irements listed in 5.5 are missing fromthe specifying document, then the recommendations for theseveral variables shall be followed.5.7 Unless the items listed in 5.5 are specified, tests madewith such inadequate reference to this test method are not inconformance with this test method. If the items

32、 listed in 5.5 arenot closely controlled during the test, it is possible that theprecisions stated in 15.2 and 15.3 will not be obtained.5.8 Variations in the failure criteria (current setting andresponse time) of the current sensing element significantlyaffect the test results.5.9 Appendix X1. cont

33、ains a more complete discussion ofthe significance of dielectric strength tests.6. Apparatus6.1 Voltage SourceObtain the test voltage from a step-uptransformer supplied from a variable sinusoidal low-voltage6Available from International Electrotechnical Commission (IEC), 3 rue deVaremb, Case postale

34、 131, CH-1211, Geneva 20, Switzerland, http:/www.iec.ch.7Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.D149 09 (2013)2source. The transformer, its voltage source, and the associatedcontrols shall have the following capab

35、ilities:6.1.1 The ratio of crest to root-mean-square (rms) testvoltage shall be equal to =265%1.34 to 1.48!, with the testspecimen in the circuit, at all voltages greater than 50 % of thebreakdown voltage.6.1.2 The capacity of the source shall be sufficient tomaintain the test voltage until dielectr

36、ic breakdown occurs. Formost materials, using electrodes similar to those shown inTable 1, an output current capacity of 40 mA is usuallysatisfactory. For more complex electrode structures, or fortesting high-loss materials, it is possible that higher currentcapacity will be needed. The power rating

37、 for most tests willvary from 0.5 kVA for testing low-capacitance specimens atvoltages up to 10 kV, to 5 kVA for voltages up to 100 kV.6.1.3 The controls on the variable low-voltage source shallbe capable of varying the supply voltage and the resultant testvoltage smoothly, uniformly, and without ov

38、ershoots ortransients, in accordance with 12.2. Do not allow the peakvoltage to exceed 1.48 times the indicated rms test voltageunder any circumstance. Motor-driven controls are preferablefor making short-time (see 12.2.1) or slow-rate-of-rise (see12.2.3) tests.6.1.4 Equip the voltage source with a

39、circuit-breakingdevice that will operate within three cycles. The device shalldisconnect the voltage-source equipment from the powerservice and protect it from overload as a result of specimenbreakdown causing an overload of the testing apparatus. Ifprolonged current follows breakdown it will result

40、 in unnec-essary burning of the test specimens, pitting of the electrodes,and contamination of any liquid surrounding medium.6.1.5 It is important for the circuit-breaking device to havean adjustable current-sensing element in the step-up trans-former secondary, to allow for adjustment consistent wi

41、th thespecimen characteristics and arranged to sense specimen cur-rent. Set the sensing element to respond to a current that isindicative of specimen breakdown as defined in 12.3.6.1.6 The current setting is likely to have a significant effecton the test results. Make the setting high enough that tr

42、ansients,such as partial discharges, will not trip the breaker but not sohigh that excessive burning of the specimen, with resultantelectrode damage, will occur on breakdown. The optimumcurrent setting is not the same for all specimens and dependingupon the intended use of the material and the purpo

43、se of thetest, it is often desirable to make tests on a given sample atmore than one current setting. The electrode area is likely tohave a significant effect upon the choice of current setting.6.1.7 It is possible that the specimen current-sensing ele-ment will be in the primary of the step-up tran

44、sformer.Calibrate the current-sensing dial in terms of specimen current.6.1.8 Exercise care in setting the response of the currentcontrol. If the control is set too high, the circuit will notrespond when breakdown occurs; if set too low, it is possiblethat it will respond to leakage currents, capaci

45、tive currents, orpartial discharge (corona) currents or, when the sensing ele-ment is located in the primary, to the step-up transformermagnetizing current.6.2 Voltage MeasurementA voltmeter must be providedfor measuring the rms test voltage. If a peak-reading voltmeteris used, divide the reading by

46、 =2 to get rms values. Theoverall error of the voltage-measuring circuit shall not exceed5 % of the measured value. In addition, the response time ofTABLE 1 Typical Electrodes for Dielectric Strength Testing of Various Types of Insulating MaterialsAElectrodeTypeDescription of ElectrodesB,CInsulating

47、 Materials1 Opposing cylinders 51 mm (2 in.) in diameter, 25 mm (1 in.) thick withedges rounded to 6.4 mm (0.25 in.) radiusflat sheets of paper, films, fabrics, rubber, molded plastics, laminates,boards, glass, mica, and ceramic2 Opposing cylinders 25 mm (1 in.) in diameter, 25 mm (1 in.) thick with

48、edges rounded to 3.2 mm (0.125 in.) radiussame as for Type 1, particularly for glass, mica, plastic, and ceramic3 Opposing cylindrical rods 6.4 mm (0.25 in.) in diameter with edgesrounded to 0.8 mm (0.0313 in.) radiusDsame as for Type 1, particularly for varnish, plastic, and other thin film andtape

49、s: where small specimens necessitate the use of smaller electrodes,or where testing of a small area is desired4 Flat plates 6.4 mm (0.25 in.) wide and 108 mm (4.25 in.) long with edgessquare and ends rounded to 3.2 mm (0.125 in.) radiussame as for Type 1, particularly for rubber tapes and other narrow widthsof thin materials5 Hemispherical electrodes 12.7 mm (0.5 in.) in diameterEfilling and treating compounds, gels and semisolid compounds and greases,embedding, potting, and encapsulating materials6 Opposing cylinders; the lower one 75 mm (3 in.) in diameter, 15 mm(0.6