1、Designation:D330000 (Reapproved 2006) Designation: D3300 12Standard Test Method forDielectric Breakdown Voltage of Insulating Oils ofPetroleum Origin Under Impulse Conditions1This standard is issued under the fixed designation D3300; the number immediately following the designation indicates the yea
2、r 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.1. Scope1.1 This test method covers the determination of the dielec
3、tric breakdown voltage of insulating oils in a highly divergent fieldunder impulse conditions.1.2 The values stated in inch-pound units are to be regarded as the standard. The values stated in inch-pound units are to beregarded as standard. The values given in parentheses are mathematical conversion
4、s to SI units that are provided for informationonly and are not considered standard.1.3 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 and health practices and
5、 determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D923 Practices for Sampling Electrical Insulating LiquidsD2864 Terminology Relating to Electrical Insulating Liquids and Gases2.2 IEEE Documents:IEEE Standard 4-1995 Techniques for High-Volt
6、age Testing33. Significance and Use3.1 This test method is most commonly performed using a negative polarity point opposing a grounded sphere (NPS). The NPSbreakdown voltage of fresh unused oils measured in the highly divergent field in this configuration depends on oil composition,decreasing with i
7、ncreasing concentration of aromatic, particularly polyaromatic, hydrocarbon molecules.3.2 This test method may be used to evaluate the continuity of composition of an oil from shipment to shipment. The NPSimpulse breakdown voltage of an oil can also be substantially lowered by contact with materials
8、 of construction, by service aging,and by other impurities. Test results lower than those expected for a given fresh oil may also indicate use or contamination of thatoil.3.3 Although polarity of the voltage wave has little or no effect on the breakdown strength of an oil in uniform fields, polarity
9、does have a marked effect on the breakdown voltage of an oil in nonuniform electric fields.3.4 Transient voltages may also vary over a wide range in both the time to reach crest value and the time to decay to half crestor to zero magnitude. The IEEE standard lightning impulse test (see 2.2) specifie
10、s a 1.2 by 50-s negative polarity wave.4. Apparatus4.1 Impulse Generator, capable of producing a standard 1.2 by 50-s full wave adjustable to positive or negative polarity. Thegenerator shall have a nominal voltage rating of at least 300 kV adjustable in 10-kV steps. Generators having a capability o
11、f 1000Ws (1000 J) at 300 kV have been found satisfactory.4.2 Voltage-Control EquipmentThe controls shall include a suitable measuring device for predetermining the crest voltage towithin 65 %. A voltage stabilizer is desirable at the input to the d-c power supply used for charging the impulse-genera
12、torcapacitors.4.3 Electrodes:1This test method is under the jurisdiction of ASTM Committee D27 on Electrical Insulating Liquids and Gases and is the direct responsibility of Subcommittee D27.05on Electrical Test.Current edition approved Nov.Jan. 1, 2006.2012. Published January 2007.2012. Originally
13、approved in 1974. Last previous edition approved in 20002006 asD3300 00(2006). DOI: 10.1520/D3300-00R06.10.1520/D3300-12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, ref
14、er to the standards Document Summary page on the ASTM website.3Available from the Institute of Electrical and Electronics Engineers, 445 Hoes Lane, Piscataway, NJ 08855-1331.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what chan
15、ges 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 standard as published by ASTM is to be considered the offic
16、ial document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.3.1 The electrodes shall consist of a polished steel or brass sphere of 0.5 in. (12.7 mm) diameter and a steel point. The pointmay be an ordinary steel phonograph needle w
17、ith a 0.06 mm 6 20 % radius of curvature of point or a No. 18 Filter Pointneedle.point.4Needles with drawn tips are not recommended.4.3.2 The effect of variation in the radius of curvature of point is subject to further investigation. Both electrodes shall be easilyreplaceable.4.4 Test Cell:4.4.1 Th
18、e test cell shall be made of a material of high dielectric strength and of such dimensions that the electrical breakdownis restricted to the electrode gap. Test cell materials shall resist attack by, and be insoluble in, any of the cleaning or test liquidsused. Test cells such as those shown in Fig.
19、 1 and Fig. 2 have been found satisfactory.4.4.2 The sphere electrode shall be rigidly fixed and the point electrode mounted such that the gap may be adjusted from zeroto the required value.5. Sampling5.1 Obtain a sample of the liquid to be tested using appropriate ASTM sampling apparatus in accorda
20、nce with Practices D923.4The following steel needle has been found satisfactory for this method: Dean No. 18 Filter Point Needle, available from John Dean, Inc., 20 Mechanic St., Putnam, CT06260.4The following steel needle has been found satisfactory for this method: Type L Nickel Plated Steel Phono
21、graph Needle.The sole source of supply of the apparatus known to the committee at this time is Victrola Repair Service, 206 Cliff St., St. Johnsbury, VT, 05819. If you are aware ofalternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive ca
22、reful consideration at a meeting of the responsibletechnical committee, which you may attend.FIG. 1 Test CellD3300 1226. Adjustments and Care of Electrodes and Test Cell6.1 Electrode Spacing:6.1.1 For the cell shown in Fig. 1, reduce the electrode gap to zero spacing. Proceed very carefully to avoid
23、 damaging the point.The point of contact shall be established electrically with an ohmmeter. Open the gap to the specified spacing using a dialmicrometer or other suitable method.6.1.2 For the cell shown in Fig. 2, the gap may be set with a go-no-go gage.6.1.3 The gap spacings shall be 1.0 in. (25.4
24、 mm) for point-to-sphere and 0.15 in. (3.8 mm) for sphere-to-sphere electrodeconfiguration.6.2 CleaningDegrease the cell and electrodes by rinsing them with reagent grade petroleum ether, washing with detergent andhot water, rinsing thoroughly in hot tap water, and then rinsing them with distilled w
25、ater. Dry the cell and hardware in an ovenfor2hatapproximately 105 to 110C, remove, and store in a desiccator until needed.6.3 Daily UseUse new or polished sphere electrodes at the beginning of each days testing. Discard the point electrode andreplace it after each breakdown; replace the sphere elec
26、trodes after every five breakdowns when testing point-to-sphere. Morefrequent replacement may be necessary when testing sphere-to-sphere. Sphere electrodes may be cleaned and polished for reusein point-to-sphere testing. However, the use of polished spheres is not recommended for sphere-to-sphere te
27、sting. When not in use,clean and store the cell in accordance with 6.2.7. Test Temperature7.1 Conduct the tests with the specimen at room temperature as defined in Terminology D2864. Testing liquids at temperatureslower than that of the room may give variable and unsatisfactory results. Record the t
28、est temperature.8. Procedure8.1 Set the electrode spacing to the desired value.8.2 Rinse the test cell with a portion of the sample and discard this liquid. Slowly fill the cell with the test liquid, being carefulto avoid entraining air bubbles. Allow it to set undisturbed for 2 min prior to testing
29、.8.2.1 For the test cell shown in Fig. 1, unscrew the upper electrode holding assembly to fill it with the sample oil while holdingthe cell at an angle to prevent splashing, which could create air bubbles. Screw the top portion down until the metal flange seatsfirmly.8.3 Connect the fixed electrode
30、to ground and the movable electrode to the impulse generator.8.4 Apply the impulse wave of specified polarity starting approximately 40 kV below the expected breakdown level. Applythree impulse waves at each voltage level. Allow a minimum of 30 s between each test.8.5 Increase the voltage level in s
31、teps of 10 kV or less until breakdown occurs, noting the crest voltage level at breakdown. Itis necessary to have at least three withstand levels prior to breakdown.FIG. 2 Test CellD3300 1238.5.1 Measure the breakdown voltage using techniques specified in IEEE Standard 4.8.6 After each breakdown, ch
32、ange the point electrode and follow 8.1 and 8.2.8.7 Make five breakdown tests on five specimens from the same sample. Maintain at least two significant digits in the results.8.8 Criterion for Statistical Consistency:8.8.1 Calculate the mean and standard deviation of the five breakdowns as follows:X
33、5 n1(i51nXi! (1)where:X= mean of the five individual values,Xi= ith breakdown voltage, andn = number of breakdowns either 5 or 10.8.8.2 Using the impulse crest voltage breakdown values determined in 8.7, calculate the mean value using the equation in 8.8.1.Determine that the range of the five breakd
34、owns is no greater than 33.3 % of the mean value. If the range is acceptable, report thismean value as the impulse breakdown voltage. If the range exceeds 33.3 % of the mean value of the five breakdowns, then conductfive additional breakdowns and obtain a new mean breakdown value for the ten breakdo
35、wns. Determine the range of the tenbreakdowns and if the range is less than 54.6 % of the mean of the ten breakdowns, report this mean value as the impulsebreakdown voltage. If the allowable range is exceeded, the error is too large. Investigate the cause of the error and repeat the tests.NOTE 1The
36、criterion for statistical consistency specified apply only to negative polarity waves if point-to-sphere electrodes are used.8.9 It may be necessary to partially immerse the test cell in oil to prevent external flashover. This is necessary with the cellshown in Fig. 1.8.10 If a second insulating liq
37、uid is to be tested, thoroughly clean the test cell in accordance with 6.2.9. Report9.1 Report the following information:9.1.1 Sample identification,9.1.2 Electrode configuration, polarity, and electrode spacing,9.1.3 Impulse crest voltage for each breakdown (do not discard any data),9.1.4 Wave shap
38、e identification,9.1.5 Starting voltage crest level, voltage steps, and highest voltage withstand level,9.1.6 Mean impulse breakdown value,9.1.7 Sample water content,9.1.8 Barometric pressure, and9.1.9 Date of test.10. Precision and Bias10.1 This precision statement applies to new oil received from
39、a supplier. Using the point-to-sphere electrode configuration, thefollowing precision statements are applicable to both positive and negative polarity:10.1.1 Single Operator Precision The single operator % coefficient of variance of a single test result comprised of fivebreakdowns has been found to
40、be 3.9 %. Therefore, results of two properly conducted tests by the same operator on the samesample should not differ by more than 11 % of the average of the two tests. The maximum allowable range for the series of fivebreakdowns comprising the test result should be less than 33.3 % of the average o
41、f the five breakdowns. In the case where aten-breakdown average is used, the maximum allowable range of the individual tests comprising the result should be less than54.6 % of the average of the ten breakdowns.10.1.2 Multilaboratory Precision The multilaboratory % coefficient of variance has been fo
42、und to be 5.43 %. Therefore,results of two properly conducted tests in different laboratories on the same sample of oil should not differ by more than 15.4 %of the average of the two results.10.2 No statement can be made about the bias of this test method because a standard reference material is not
43、 available.11. Keywords11.1 dielectric breakdown; impulse voltage; insulating oilsASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the v
44、alidity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your c
45、omments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments ha
46、ve not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.D3300 124This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single o
47、r multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D3300 125
