1、Designation: D877/D877M 13Standard Test Method forDielectric Breakdown Voltage of Insulating Liquids UsingDisk Electrodes1This standard is issued under the fixed designation D877/D877M; the number immediately following the designation indicates the yearof original adoption or, in the case of revisio
2、n, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript 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 This test method
3、describes two procedures, A and B, fordetermining the electrical breakdown voltage of insulatingliquid specimens. The breakdown test uses ac voltage in thepower-frequency range from 45 to 65 Hz.1.2 This test method is used to judge if the disk electrodebreakdown voltage requirements are met for insu
4、lating liquids,as delivered from the manufacturer, that have never beenfiltered or dried. See Specification D3487, SpecificationD4652, Specification D6871 and Guide D5222 for the mini-mum specified electrical breakdown. This test method shouldbe used as recommended by professional organization stan-
5、dards such as IEEE C57.106.1.3 Limitations of the Procedures:1.3.1 The sensitivity of this test method to the generalpopulation of contaminants present in a liquid sample de-creases as applied test voltages used in this test method becomegreater than approximately 25 kV rms.1.3.2 If the concentratio
6、n of water in the sample at roomtemperature is less than 60 % of saturation, the sensitivity ofthis test method to the presence of water is decreased. Forfurther information refer to RR:D27-1006.21.3.3 The suitability for this test method has not beendetermined for a liquids viscosity higher than 90
7、0 cSt at 40C.1.4 Procedure Applications1.4.1 Procedure A:1.4.1.1 Procedure A is used to determine the breakdownvoltage of liquids in which any insoluble breakdown productseasily settle during the interval between the required repeatedbreakdown tests. These liquids include petroleum oils,hydrocarbons
8、, natural and synthetic esters, and askarels (PCB)used as insulating and cooling liquids in transformers, cables,and similar apparatus.1.4.1.2 Procedure A may be used to obtain the dielectricbreakdown of silicone fluid as specified in Test MethodsD2225, provided the discharge energy into the sample
9、is lessthan 20 mJ (milli joule) per breakdown for five consecutivebreakdowns.1.4.2 Procedure B:1.4.2.1 This procedure is used to determine the breakdownvoltage of liquids in which any insoluble breakdown productsdo not completely settle from the space between the disksduring the 1min interval requir
10、ed in Procedure A. ProcedureB, modified in accordance with Section 17 of Test MethodsD2225, is acceptable for testing silicone dielectric liquids if therequirements of 1.4.1.2 can not be achieved.1.4.2.2 Procedure B should also be applied for the determi-nation of the breakdown voltage of liquid sam
11、ples containinginsoluble materials that settle from the specimen during testing.These may include samples taken from circuit breakers, loadtap changers, and other liquids heavily contaminated withinsoluble particulate material. These examples representsamples that may have large differences between
12、replicatetests. The use of Procedure B will result in a more accuratevalue of breakdown voltage when testing such liquids.1.4.2.3 Use Procedure B to establish the breakdown voltageof an insulating liquid where an ASTM specification does notexist or when developing a value for an ASTM guide orstandar
13、d. Procedure A may be used once the single operatorprecision of 13.1 has been demonstrated.1.5 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independ
14、ently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.6 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
15、health practices and determine the applica-bility of regulatory limitations prior to use.1This test method is under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquids and Gases and is the direct responsibility of Subcom-mittee D27.05 on Electrical Test.Current edition approved De
16、c. 1, 2013. Published January 2014. Originallyapproved in 1946. Last previous edition approved in 2007 as D87702(2007). DOI:10.1520/D0877_D0877M-13.2RR:D27-1006, Round-Robin Data Using Modified VDE Electrode Cell forDielectric Strength Tests on Oil, is available from ASTM Headquarters.Copyright ASTM
17、 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12. Referenced Documents2.1 ASTM Standards:3D923 Practices for Sampling Electrical Insulating LiquidsD1816 Test Method for Dielectric Breakdown Voltage ofInsulating Liquids Using VDE ElectrodesD2225 Te
18、st Methods for Silicone Fluids Used for ElectricalInsulationD2864 Terminology Relating to Electrical Insulating Liq-uids and GasesD3487 Specification for Mineral Insulating Oil Used inElectrical ApparatusD4652 Specification for Silicone Fluid Used for ElectricalInsulationD5222 Specification for High
19、 Fire-Point Mineral ElectricalInsulating OilsD6871 Specification for Natural (Vegetable Oil) Ester FluidsUsed in Electrical Apparatus2.2 IEEE Standards:4Standard 4, IEEE Standard Techniques for High-VoltageTestingC57.106 Guide for Acceptance and Maintenance of Insulat-ing Oil in Equipment3. Signific
20、ance and Use3.1 The dielectric breakdown voltage is a measure of theability of an insulating liquid to withstand electrical stress. Thepower-frequency breakdown voltage of a liquid is reduced bythe presence of contaminants such as cellulosic fibers, conduct-ing particles, dirt, and water. A low resu
21、lt in this test methodindicates the presence of significant concentrations of one ormore of these contaminants in the liquid tested. See AppendixX1.3.2 A high breakdown voltage measured in this test methoddoes not necessarily indicate that the amount of the contami-nants present in a liquid from whi
22、ch the sample was taken issufficiently low for the sampled liquid to be acceptable in allelectrical equipment. Test Method D877 is not sensitive to lowlevels of these contaminants. Breakdown in this test method isdominated by events occurring at the electrode edges. Thevoltage stress distribution be
23、tween the parallel disk electrodesused in this test method are quasi-uniform and there issubstantial stress concentration at the sharp edges of the flatdisk faces.3.3 This test method may be used for evaluation of insulat-ing liquids in equipment that is designed to be filled withunprocessed liquids
24、 as delivered by a vendor.3.4 This test method is not recommended for evaluation ofthe breakdown voltage of liquids used in equipment thatrequires the application of vacuum and filtering of the oilbefore being placed into service. Test Method D1816 should beused to determine the breakdown voltage of
25、 filtered anddegassed liquids.3.5 This test method is used in laboratory or field tests. Forfield breakdown results to be comparable to laboratory results,all criteria including room temperature (20 to 30C) must bemet.4. Electrical Apparatus4.1 In addition to this section, use IEEE Standard 4 todete
26、rmine other requirements necessary for conducting testmethods and making measurements using alternating voltages.Procedures to ensure accuracy should follow the requirementsof IEEE Standard 4. Calibration(s) shall be traceable tonational standards and should be conducted annually or moreoften.4.1.1
27、Test VoltageThe test voltage shall be an alternatingvoltage having a frequency in the range from 45 to 65 Hz,normally referred to as power-frequency voltage. The voltagewaveshape should approximate a sinusoid with both half cyclesclosely alike, and it should have a ratio of peak-to-rms valuesequal t
28、o the square root of 2 within 65%.4.1.2 Generation of the Test Voltage The test voltage isgenerally supplied by a transformer or resonant circuit. Thevoltage in the test circuit should be stable enough to bepractically unaffected by varying current flowing in the capaci-tive and resistive paths of t
29、he test circuit. Nondisruptivedischarges in the test circuit should not reduce the test voltageto such an extent, and for such a time, that the disruptivedischarge (breakdown) voltage of the test specimen is signifi-cantly affected. In the case of a transformer, the short-circuitcurrent delivered by
30、 the transformer should be sufficient tomaintain the test voltage within 3 % during transient currentpulses or discharges, and a short circuit current of 0.1 A maysuffice.4.1.3 Disruptive Voltage Measurement Design the mea-surement circuit so the voltage recorded at the breakdown isthe maximum volta
31、ge across the test specimen immediatelyprior to the disruptive breakdown with an error no greater than3%.4.2 Circuit-Interrupting Equipment Design the circuitused to interrupt the disruptive discharge through the specimento operate when the voltage across the specimen has collapsedto less than 100 V
32、. It is recommended that the circuit designlimit the disruptive current duration and magnitude to lowvalues that will minimize damage to the disks and limitformation of non-soluble materials resulting from thebreakdown, but consistent with the requirements of 4.1.1.4.3 Voltage Control EquipmentUse a
33、 rate of voltage riseof 3 kV/s. The tolerance of the rate of rise should be 5 % forany new equipment. Automatic equipment should be used tocontrol the voltage rate of rise because of the difficulty ofmaintaining a uniform voltage rise manually. The equipmentshould produce a straight-line voltage-tim
34、e curve over theoperating range of the equipment. Calibrate and label auto-matic controls in terms of rate-of-rise.3For 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 t
35、he standards Document Summary page onthe ASTM website.4Available from The Institute of Electrical and Electronics Engineers, Inc., POBox 1331, Piscataway, NJ 08855.D877/D877M 1324.4 Measuring SystemsThe voltage shall be measured bya method that fulfills the requirements of IEEE Standard No. 4,giving
36、 rms values.4.5 Connect the electrodes such that the voltage measuredfrom each electrode with respect to ground during the test isequal within 5 %.5. Electrodes5.1 The electrodes shall have parallel faces and axes in acoincident horizontal line when mounted in the cup. Constructthe electrodes of pol
37、ished brass as disks 25.4 mm 1.0 in. indiameter 62.0 %, and at least 3.18 mm 18 in. thick, and withsharp edges. The sharp edge shall have a quarter circle radiusno greater than 0.254 mm 0.010 in. Refer to Annex A1 forillustrations of measuring edge radius.6. Test Cup6.1 Construct the cup of a materi
38、al having high dielectricstrength, that is inert to any of the cleaning or test liquids. Thecup material shall not absorb moisture or the cleaning and testliquids. The vector sum of the resistive and capacitive currentof the cup, when filled with oil meeting the requirements ofSpecification D3487, s
39、hall be less than 200 A at 20 kV, atpower frequency. Construct the cup so that no part is less than12.7 mm 0.5 in. from any part (the side, back or edge) of theelectrode disk. The cup shall be designed to permit easyremoval of the electrodes for cleaning and polishing, verifica-tion that the sharp e
40、dge is within the specified tolerance, and topermit easy adjustment of the gap spacing. The top of the cupshall be maintained at least 25.4 mm 1.0 in. above the top ofthe electrodes.7. Adjustment and Care of Electrodes and Test Cup7.1 Daily UseAt the beginning of each days testingexamine the electro
41、des for scratches, pitting, and contamina-tion. If pitting or scratches of the disk faces are found, polishin accordance with 7.5. For severe problems resurfacing maybe required. The electrodes should be examined quarterly inaccordance with 7.4 for the proper sharp edge, if there isapparent edge dam
42、age, or upon return from resurfacing. Thegap shall be reset in accordance with 7.2. Clean and prepare thecup in accordance with 7.3.7.2 Electrode SpacingGauges shall be used to set thespacing of the electrodes during tests to 2.54 mm 0.100 in. +0.0254 mm 0.001 in. The gap should be set with “go” and
43、“no-go” gauges such that the spacing is no less than 2.51 mm0.0990 in. for a “go” measurement and no larger than 2.57mm 0.1010 in. If the “no-go” gauge can enter the gap, thegap must be reset. Alternatively, if the cup is supplied with avernier scale for setting the gap, it can be used following the
44、manufacturers instructions. Vernier scales are to be verified atleast monthly with gauges. Recheck the spacing following anydisturbance of the cup or electrodes and at operation in thebeginning of each days testing.7.3 CleaningWipe the electrodes and the cup clean withdry, lint-free tissue paper or
45、a clean dry chamois. It is importantto avoid touching the electrodes or the cleaned gauge with thefingers or with portions of the tissue paper or chamois that havebeen in contact with the hands. After adjustment of the gapspacing, the cup shall be rinsed with a dry solvent. Alow-boiling solvent shou
46、ld not be used as its rapid evaporationmay cool the cup, causing moisture condensation. If thisoccurs, the cup should be warmed slightly to evaporate anymoisture before use. Take care to avoid touching the electrodesor the inside of the cup after cleaning. Flush the cup using partof the sample. Fill
47、 the cup with a specimen from a sample witha known breakdown voltage. Make a voltage breakdown test asspecified in this test method. If the breakdown voltage isjudged in the proper range for the sample with a knownbreakdown value, the test cup is prepared for testing othersamples. If a value lower t
48、han expected is obtained, flush orclean the cup as necessary until test results meet the expectedvalue for the known sample.7.4 Electrode Edge VerificationUsing a 0.254-mm 0.010-in. equivalent radius gauge5or an optical comparator, verifythat the radius of the edge of the electrode, on the gap side,
49、 isless than 0.254 mm 0.010 in.; verify the face of the electrodesare at 90 6 1 to the side edge of the electrode. If the edgeradius is no greater than the value specified and the sides are at90, the electrodes are satisfactory for continued use. Checkthe disk in at least four locations for each criteria. If the radiusexceeds the tolerance or the edges are not at 90, the electrodesshall be resurfaced to the specified values. Refer to Annex A1for illustrations of measuring edge radius.7.5 Polishing of ElectrodesWhen examination of elec-t
