1、Designation: D1816 12Standard Test Method forDielectric Breakdown Voltage of Insulating Liquids UsingVDE Electrodes1This standard is issued under the fixed designation D1816; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、 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.1. Scope*1.1 This test method covers the determination of the dielec-tric breakdown voltage of insulating liquids (oils of pet
3、roleumorigin, silicone fluids, high fire-point mineral electrical insu-lating oils, synthetic ester fluids and natural ester fluids). Thistest method is applicable to insulating liquids commonly usedin cables, transformers, oil circuit breakers, and similar appa-ratus as an insulating and cooling me
4、dium. Refer to Terminol-ogy D2864 for definitions used in this test method.1.2 This test method is sensitive to the deleterious effects ofmoisture in solution especially when cellulosic fibers arepresent in the liquid. It has been found to be especially usefulin diagnostic and laboratory investigati
5、ons of the dielectricbreakdown strength of insulating liquid in insulating systems.21.3 This test method is used to judge if the VDE electrodebreakdown voltage requirements are met for insulating liquids.This test method should be used as recommended by profes-sional organization standards such as I
6、EEE C57.106.1.4 This test method may be used to obtain the dielectricbreakdown of silicone fluid as specified in Test Method D2225and Specification D4652, provided that the discharge energyinto the sample is less than 20 mJ (milli joule) per breakdownfor five consecutive breakdowns.1.5 Both the metr
7、ic and the alternative inch-pound units areacceptable.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 health practices and determine the applica-bility
8、of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D235 Specification for Mineral Spirits (Petroleum Spirits)(Hydrocarbon Dry Cleaning Solvent)D923 Practices for Sampling Electrical Insulating LiquidsD2225 Test Methods for Silicone Fluids Used for ElectricalInsulationD
9、2864 Terminology Relating to Electrical Insulating Liq-uids and GasesD3487 Specification for Mineral Insulating Oil Used inElectrical ApparatusD4652 Specification for Silicone Fluid Used for ElectricalInsulationD6871 Specification for Natural (Vegetable Oil) Ester FluidsUsed in Electrical Apparatus2
10、.2 IEEE Standard:Standard 4 IEEE Standard Techniques for High VoltageTesting4C57.106 Guide for Acceptance and Maintenance of Insulat-ing Oil in Equipment43. Significance and Use3.1 The dielectric breakdown voltage of an insulating liquidis of importance as a measure of the liquids ability towithstan
11、d electric stress without failure. The dielectric break-down voltage serves to indicate the presence of contaminatingagents such as water, dirt, cellulosic fibers, or conductingparticles in the liquid, one or more of which may be present insignificant concentrations when low breakdown voltages areob
12、tained. However, a high dielectric breakdown voltage doesnot necessarily indicate the absence of all contaminants; it maymerely indicate that the concentrations of contaminants that arepresent in the liquid between the electrodes are not largeenough to deleteriously affect the average breakdown volt
13、ageof the liquid when tested by this test method (see AppendixX1.)1This test method is under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquids and Gasesand is the direct responsibility of Subcom-mittee D27.05 on Electrical Test.Current edition approved June 15, 2012. Published J
14、uly 2012. Originallyapproved in 1960 as D1816 60 T. Last previous edition approved in 2004 asD1816 04. DOI: 10.1520/D1816-12.2Supporting data is available from ASTM Headquarters. Request RR:D27-1006.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service
15、 at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available from the Institute of Electrical and Electronic Engineers, Inc., POBox 1331, Piscataway, NJ 08855.*A Summary of Changes section appears at the end of t
16、his standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2 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 30
17、C) must bemet.4. Electrical Apparatus4.1 In addition to this section, use IEEE Standard 4 todetermine other requirements necesary for conducting testmeasurements, and maintaining error limits using alternatingvoltages. Procedures to ensure accuracy should follow therequirements of IEEE Standard 4. C
18、alibration(s) shall betraceable to national standards and calibration should beverified annually or more often to ensure accuracy require-ments. IEEE Standard 4 is required during the manufacturingof the test apparatus and utilized during calibration of theequipment.4.1.1 Test VoltageThe test voltag
19、e shall be an alternatingvoltage having a frequency in the range from 45 to 65 Hz,normally referred to as power-frequency voltage. The voltagewave shape should approximate a sinusoid with both halfcycles closely alike, and it should have a ratio of peak-to-rmsvalues equal to the square root of 2 wit
20、hin 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 beunaffected by varying current flowing in the capacitive andresistive paths of the test circuit. Non-disruptive discharg
21、es inthe test circuit should not reduce the test voltage to such anextent, and for such a time, that the disruptive discharge(breakdown) voltage of the test specimen is significantlyaffected. In the case of a transformer, the short-circuit currentdelivered by the transformer should be sufficient to
22、maintainthe test voltage within 3 % during transient current pulses ordischarges, and a short circuit current of 0.1 A may suffice.4.1.3 Disruptive Voltage Measurement Design the mea-surement circuit so the voltage recorded at the breakdown isthe maximum voltage across the test specimen immediatelyp
23、rior 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. It is recommended that the circuit de
24、signlimit the disruptive current duration and magnitude to lowvalues that will minimize damage to the electrodes and limitformation of non-soluble materials resulting from the break-down, but consistent with the requirements of 4.1.2, but in nocase should the short-circuit current exceed 1 mA/kV ofa
25、pplied voltage.4.3 Voltage Control EquipmentUse a rate of voltage riseof 0.5 kV/s. The tolerance of the rate of rise should be 5 % forany new equipment manufactured after the year 2000. Auto-matic equipment should be used to control the voltage rate ofrise because of the difficulty of maintaining a
26、uniform voltagerise manually. The equipment should produce a straight-linevoltage-time curve over the operating range of the equipment.Calibrate and label automatic controls in terms of rate-of-rise.4.4 Measuring SystemsThe voltage shall be measured bya method that fufills the requirements of IEEE S
27、tandard No. 4,giving rms values.4.5 Connect the electrode such that the voltage measuredfrom each electrode with respect to ground during the test isequal within 5 %.4.6 AccuracyThe combined accuracy of the voltmeter andvoltage divider circuit shall be such that measurement errordoes not exceed 3 %
28、at the rate-of-voltage rise specified in 4.3.For equipment manufactured prior to 1995 the maximumallowable error is 5 %.5. Electrodes5.1 The electrodes shall be polished brass spherically-capped electrodes of the VDE (Verband Deutscher Elektrotech-niker, Specification 0370) type having the dimension
29、s shownin Fig. 1 61 %, mounted with axes horizontal and coincidentwithin 61 mm.6. Test Cell6.1 The test cell shall be designed to permit easy removal ofthe electrodes for cleaning and polishing, verification that theshape is within the specified tolerance, and to permit easyadjustment of the gap spa
30、cing. The vector sum of the resistiveand capacitive current of the cup, when filled with oil meetingthe requirements of Specification D3487, shall be less than 200A at 20 kV, at power frequency. Mount the electrodes rigidlyfrom opposite sides with the spacing axially centered within61 mm. Clearance
31、from the electrodes to all sides, bottom,cover or baffle, and any part of the stirring device is at least12.7 mm (12 in.). Provide the test cell with a motor-driventwo-bladed impeller and drive shaft, constructed of a materialhaving high dielectric strength. The two-bladed impeller is 35mm (138 in.)
32、 65 % between the blade extremities, having apitch of 40 mm (1.57 in.) 65 % (blade angle of twenty degreesFIG. 1 VDE ElectrodeD1816 122(20) 6 5 %), operating at a speed between 200 and 300 rpm.The impeller, located below the lower edge of the electrodes,rotates in such a direction that the resulting
33、 liquid flow isdirected downward against the bottom of the test cell. Con-struct the test cell of a material of high dielectric strength, thatis not soluble in or attacked by any of the cleaning or testliquids used, and is nonabsorbent to moisture and the cleaningand test liquids. So that the breakd
34、own may be observed,transparent materials are desirable, but not essential. In order topreclude stirring air with the sample, provide the cell with acover or baffle that will effectively prevent air from contactingthe circulating liquid.7. Adjustment and Care of Electrodes and Test Cell7.1 Electrode
35、 SpacingWith the electrodes held firmly inplace, check the electrodes with a standard round gage for 2 60.03-mm (0.079-in.) spacing. If a dielectric breakdown doesnot occur during any of the consecutive breakdown tests usingthe 2 mm spacing or the sample is not adequate for the 2 mmspacing test cell
36、 a 1 6 0.03-mm (0.039-in.) spacing should beused to determine the breakdown voltage and the spacingreported. Flat “go” and “no-go” gages may be substitutedhaving thicknesses of the specified value 60.03 mm forelectrode spacing of 1 or 2 mm. If it is necessary to readjust theelectrodes, set the elect
37、rodes firmly in place and check thespacing. For referee tests or tests that will be used for closecomparisons, the laboratories shall agree in advance on thespacing for the tests and ensure that all other requirements ofthis test method are met. The spacing agreed upon shall bemeasured with the gage
38、 that corresponds exactly to the selectedspacing within tolerance stated above for the gage.7.2 CleaningWipe the electrodes and cell clean with dry,lint-free tissue paper, or a clean dry chamois. It is important toavoid touching the electrodes or the cleaned gage with thefingers or with portions of
39、the tissue paper or chamois that havebeen in contact with the hands.After adjustment of the spacing,rinse the cell with a dry hydrocarbon solvent, such as kerosineor solvents of Specification D235. Do not use a low boilingpoint solvent, as its rapid evaporation may cool the cell,causing moisture con
40、densation. If this occurs, before using,warm the cell to evaporate the moisture. Avoid touching theelectrodes or the inside of the cell after cleaning. Afterthorough cleaning, flush the cell with new insulating liquid ofthe type to be tested that is filtered through a 5-micron filter orsmaller and c
41、ontaining less than 25 ppm moisture. Conduct avoltage breakdown test on a specimen of this insulating liquidin the manner specified in this test method. If the breakdownvoltage is in the expected range for this conditioned insulatingliquid, the cell is considered properly prepared for testing others
42、amples. A lower than anticipated value is considered asevidence of cell contamination; then repeat the cleaning andthe breakdown test with clean dry insulating liquid.7.3 Daily UseAt the beginning of each days testing, theelectrodes shall be examined for pitting and carbon accumula-tion, and the spa
43、cing checked. If the test of any sample is belowthe breakdown value being used by the operator as a minimumsatisfactory value, drain the cell and flush the cell with newinsulating liquid of the type to be tested that is filtered througha 5-micron filter and containing less than 25 ppm moisturebefore
44、 testing the next specimen. When not in use, keep the cellfilled with oil that meets the requirements of SpecificationD3487 of the type normally tested. Alternatively, the cell maybe stored empty in a dust-free cabinet.At the beginning of eachdays testing, clean according to 7.2.7.4 Polishing of Ele
45、ctrodesWhen electrodes show slightetching, scratching, pitting, or carbon accumulation, theyshould be removed from the test cup and polished by buffingwith jewelers rouge using a soft cloth or soft buffing wheel.The residue from the buffing should be removed by repeatedwiping with lint-free tissue p
46、aper saturated with a suitablesolvent, followed by solvent rinsing or ultrasonic cleaning.After careful inspection, any electrodes from which pittingcannot be removed by light buffing should be discarded, asmore refinishing would destroy the electrode contour anddimensions shown in Fig. 1. Reinstall
47、 the electrodes in the testcup and adjust spacing and clean in accordance with 7.1 and7.2.8. Sampling8.1 Obtain a sample of the insulating liquid to be testedusing appropriate ASTM sampling apparatus. Insulating liquidsampling procedures are detailed in Practice D923. Particularreference should be m
48、ade to the general precaution statementof this test method. The sample shall be taken in a dry, clean,non-permeable bottle. Tightly seal and shield from light untilready to be tested. Plastic bottles are permeable and moisturecontent of the sample may change resulting in a measurabledifference when
49、compared to samples collected in non-permeable containers. Prior to starting the test, the sample shallbe inspected for the presence of moisture, sludge, metallicparticles, or other foreign matter. If the sample shows evidenceof free water, the dielectric breakdown test should be waived,and the sample reported as unsatisfactory.9. Test Procedure9.1 Allow the sample and the test cup to equilibrate toambient temperature. Laboratory and referee tests shall beconducted at room temperature (20 to 30C).9.2 To ensure a homogenous sample, gently invert and swirlthe sam
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