1、Designation: D2132 12Standard Test Method forDust-and-Fog Tracking and Erosion Resistance of ElectricalInsulating Materials1This standard is issued under the fixed designation D2132; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、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 is intended to differentiate solid elec-trical insulating materials with respect to their
3、 resistance to theaction of electric arcs produced by conduction through surfacefilms of a specified contaminant containing moisture. TestMethods D2302 and D2303 are also useful to evaluate mate-rials.1.2 The values stated in inch-pound units are the standard,except in cases where SI units are more
4、appropriate. The valuesin parentheses are for information only.1.3 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 applic
5、a-bility of regulatory limitations prior to use. Specific precau-tionary statements are given in 12.4.NOTE 1There is no equivalent ISO standard.2. Referenced Documents2.1 ASTM Standards:2D709 Specification for Laminated Thermosetting MaterialsD1711 Terminology Relating to Electrical InsulationD2302
6、Method of Test for Differential Wet Tracking Resis-tance of Electrical Insulating Materials with ControlledWater-to-Metal Discharges (Withdrawn 1982)3D2303 Test Methods for Liquid-Contaminant, Inclined-Plane Tracking and Erosion of Insulating Materials3. Terminology3.1 Definitions:3.1.1 For definiti
7、ons pertinent to this test method see Ter-minology D1711.4. High Voltage Hazard4.1 Lethal voltages are a potential hazard during the perfor-mance of this test. It is essential that the test apparatus, and allassociated equipment electrically connected to it, be properlydesigned and installed for saf
8、e operation.4.2 Solidly ground all electrically conductive parts which itis possible for a person to contact during the test.4.3 Provide means for use at the completion of any test toground any parts which were at high voltage during the test orhave the potential for acquiring an induced charge duri
9、ng thetest or retaining a charge even after disconnection of thevoltage source.4.4 Thoroughly instruct all operators as to the correctprocedures for performing tests safely.4.5 When making high voltage tests, particularly in com-pressed gas or in oil, it is possible for the energy released atbreakdo
10、wn to be sufficient to result in fire, explosion, orrupture of the test chamber. Design test equipment, testchambers, and test specimens so as to minimize the possibilityof such occurrences and to eliminate the possibility of personalinjury.NOTE 2If the potential for fire exists, have fire suppressi
11、on equipmentavailable.5. Summary of Test Method5.1 With electrodes mounted as shown in Fig. 1, coat testspecimens with a synthetic dust and test in a chamber shown inFig. 2. Direct a water spray at the test specimen. After thesurface has been wetted, apply a 60-Hz voltage between theelectrodes.Arcin
12、g occurs across localized high-resistance areasproduced by nonuniform evaporation of the water from thecontaminant. These arcs produce high temperatures in theunderlying insulation with resultant carbonization of mostorganic materials. The carbonization concentrates the electricfield. It is possible
13、 further carbonization will occur in thedirection of the field. In such cases, a carbon track is formedwhich spans the distance between the electrodes and causesfailure. It is possible that materials that do not track will erode1This test method is under the jurisdiction of ASTM Committee D09 onElec
14、trical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.07 on Electrical Insulating Materials.Current edition approved Jan. 1, 2012. Published February 2012. Originallyapproved in 1962. Last previous edition approved in 2011 as D2132 11. DOI:10.1520/D2132-12.2F
15、or 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.3The last approved version of this historical standard is refer
16、enced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for th
17、eDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1under the action of the arcing. Such erosion usually progressesfrom an upper electrode through the thickness of the specimentowards the underlying e
18、lectrode.5.2 Rate materials that track in terms of the time required toform a track between the electrodes.5.3 Rate materials that do not track in terms of the timerequired to erode to failure.5.4 Failure will be indicated when the current increasessufficiently to actuate an overcurrent device.NOTE
19、3The conditions of this test favor the formation of a track forseveral possible reasons. Most important, the continuous renewal of theconducting properties of the contaminant by the water spray allows a trackto grow progressively over long periods of time.6. Significance and Use6.1 MethodIt is possi
20、ble that electrical insulation in ser-vice will fail as a result of tracking, erosion, or a combinationof both, if exposed to high relative humidity and contaminationenvironments. This is particularly true of organic insulations inoutdoor applications where the surface of the insulation be-comes con
21、taminated by deposits of moisture and dirt, forexample, coal dust or salt spray. This test method is anaccelerated test that simulates extremely severe outdoor con-tamination. It is believed that the most severe conditions likelyto be encountered in outdoor service in the United States willbe relati
22、vely mild compared to the conditions specified in thistest method.6.2 Test ResultsMaterials can be classified by this testmethod as tracking-resistant, tracking-affected, or tracking-susceptible. The exact test values for these categories as theyapply to specific uses will be specified in the approp
23、riatematerial specifications, but guideline figures are suggested inNote 4. Tracking-resistant materials, unless erosion failureoccurs first, have the potential to last many hundreds of hours(Note 5). Erosion, though it is possible that it will progresslaterally, generally results in a failure perpe
24、ndicular to thespecimen surface. Therefore, compare only specimens of thesame nominal thickness for resistance to tracking-inducederosion. Estimate the extent of erosion from measurements ofthe depth of penetration of the erosion. Place materials that arenot tracking-susceptible in three broad categ
25、orieserosion-resistant, erosion-affected, and erosion-susceptible. When thestandard thickness specimen is tested, the following times tofailure typify the categories (Note 6):Erosion-susceptible 5 to 50 hErosion-affected 50 to 200 hErosion-resistant over 200 hNOTE 4Tracking-susceptible materials usu
26、ally fail within 5 h.Tracking-affected materials usually fail before about 100 h.NOTE 5This information is derived from the individual experiences ofeight laboratories using this test method since its publication as asuggested test method in June 1957, and from the results of an organizedtest progra
27、m among these laboratories.NOTE 6In a normal distribution approximately 68 % of all test valuesare included within 61 standard deviation of the mean.6.3 Interpretation of Test ResultsThis test method pro-vides information that allows classification as described in 6.2.The comparison of materials wit
28、hin the same group is likely tobe ambiguous unless three or more replicate specimens aretested. When the test method is used for specification purposes,do not establish simple minimum values without considerationof the large variance to be expected in test results. It isrecommended that quality leve
29、ls and specification minima bedetermined by statistical techniques.7. Apparatus7.1 GeneralA schematic diagram of the power supply andcontrol apparatus for testing one specimen is shown in Fig.3(a). It is generally desirable to test three or more specimenssimultaneously. It is recommended but not man
30、datory that aseparate power supply and control be used for each testspecimen. This allows “breaking-in” and recording of time tofailure separately for each specimen.Metric Equivalentsin.1812 12mm 3.2 12.7 25.4 50.8FIG. 1 Test Arrangement of Electrode System18 in. = 458 mm 20 in. = 508 mm 28 in. = 71
31、2 mmFIG. 2 Dust and Fog Test Chamber,Minimum Recommended SizeD2132 1227.2 Circuit BreakerThe circuit breaker (current relay, OL)interrupts the power supply on failure and stops the timingmeter. Use it as an ON-OFF switch and as a device forinterrupting air and water supply when all specimens fail. F
32、ig.3(b) illustrates the air and water supply circuit when threespecimens are tested using one fog nozzle. The circuit breakershall be rated at 2 to 3 A, inverse-time element type, for a115-V supply. Use a resistance, R0, to shunt the current coilduring the break-in period so that the breaker will no
33、t actuateas a result of the bright-flash currents typical of this period.Adjust the resistance to produce an effective breaker action atapproximately 6 A (115-V supply). Remove or switch out theshunt resistance after break-in.7.3 Supply Transformer4Use a supply transformer, T2,capable of supplying 1
34、500 V, 60 Hz, rms. A200-VA potentialtransformer is capable of supplying power for up to threespecimens if desired. Use a transformer with a 20:1 ratio whenused with a 115-V primary supply. Choose a transformer thatoffers an impedance between 600 and 1200 resistance and200 and 700 reactance. Accompli
35、sh this by insertion ofinductance L and resistance R1in the low-voltage side andresistance R2in the high-voltage side.7.4 Control TransformerUse a variable-ratioautotransformer, T1, to adjust the voltage as required.7.5 VoltmeterUse a voltmeter, V, in the primary side todetermine the specimen test v
36、oltage. Alternatively, use ahigh-impedance voltmeter for connection in the secondary, inwhich case take precautions to prevent electric shock to anoperator. If a voltmeter is used in the primary, calibrate itagainst secondary voltage with a secondary load of 10 mA.7.6 Monitoring ProvisionsUse an ac
37、ammeter, A, to moni-tor specimen current. Use a separate ammeter for each testspecimen. Alternatively make provisions to connect an amme-ter into each test-specimen circuit. Shunt the ammeter with anormally closed contact, PB, and a capacitance, C, to protectthe ammeter from the large intermittent c
38、urrents that occurduring break-in. Connect the capacitance, if used, by a switch,SA. After the break-in period, open the switch unless the valuesof the capacitance and ammeter impedances are such as toproduce negligible error in current measurement. Use terminalsA, B and C, D for oscilloscope monito
39、ring, for currentmeasurement with a voltmeter in combination with a resistor,or for insertion of an undercurrent relay to be used to stop theclock if the scintillation current falls below the specified value.7.7 ElectrodesUse three copper or brass electrodes12 by2by18 in. (13 by 51 by 3.2 mm), with
40、corners rounded to a18-in. (3.2-mm) radius on the top surface of the specimen andspaced 1 in. (25 mm) apart as shown in Fig. 1. Use a groundplate of copper or brass and of the same size as the testspecimen on the bottom surface and mounted on an insulatingsupport inclined 15 deg to the horizontal as
41、 shown in Fig. 1.4General Electric Type JE41, Model KAR-3, and Westinghouse Type VS, StyleNo. 687588, have been found satisfactory for this purpose.(a) Power supply and control circuit of wet tracking tests.(b) Air and water supply circuit.FIG. 3 Circuit DiagramsFIG. 4 Clamping Arrangement for Test-
42、Specimen ElectrodesD2132 123Clamp the electrodes firmly to the test specimen. A suggestedarrangement is shown in Fig. 4.7.8 Test ChamberUse a cubicle test chamber, Fig. 2, madefrom plastic or metal. The front wall is made of glass orpoly(methyl methacrylate), or contains viewing ports or doorsmade o
43、f these materials. Make the cubicle at least 20 in. (510mm) high and 28 in. (710 mm) wide. Determine the depth bythe number of specimens to be tested. Three specimens requirea minimum depth of 18 in. (460 mm). Fit the chamber withmeans for venting near the bottom of the cubicle, preferablyalong the
44、end of the chamber where the specimens are located.Limit the venting area to about 20 in.2(130 cm2) to eliminatedependence of test results on the ambient humidity.7.8.1 Mount one or more fog nozzles (Fig. 5) to obtain thespecified uniform moisture deposition on all test specimens. Itis suggested tha
45、t one fog nozzle, mounted approximately 25 in.(635 mm) straight line distance from the nozzle to the centerspecimen at a height of approximately 14 in. (355 mm) abovethese specimens, will, with a suitably adjusted deflector,produce the specified conditions for three test specimens in asingle cubicle
46、 (see Fig. 2). When only one fog nozzle is usedin the cubicle, it is recommended that additional air beintroduced into the cubicle equal to about double that flowingthrough a standard fog nozzle connected to an air supply of 5to 6 psig (34 to 41 kPa).7.8.2 Connect the fog nozzle assembly,5Fig. 6 , t
47、o an air andwater supply. Provide means to adjust the air supply to 5 to 6psig (0.035-0.04 MPa). Supply the water from a reservoirmounted below the nozzle so that the water level is approxi-mately 5 in. (125 mm) below the nozzle. Use a needle valve inthe water line to the nozzle to control the rate
48、of fog deposition.To ensure uninterrupted flow of the water to the nozzle, filterthe water to remove the dissolved air in the water.8. Artificial Contaminant8.1 Use synthetic dust of the following composition:Material Parts by WeightFling (SiO2floated),A240-mesh 85Clay, 325-meshB9Salt (NaCl), techni
49、cal grade 3Paper, filter pulpC3AFisher Scientific Co. Catalog No. S153-3 (SPD S-S3) is satisfactory for thispurpose.BR. E. Carroll, Inc., Trenton, NJ (1-800-257-9365) Suwanee Clay (325 mesh) issatisfactory for this purpose.CInternational Paper Co., 2 Manhattenville Rd. (901-419-7307) Paper filter pulp issatisfactory for this purpose.8.2 Mix the dust components in a ball mill with approxi-mately 1-in. (25-mm) diameter flint pebbles to the consistencyof a fine talcum. Milling for 72 h is usually sufficient.8.3 Dispense the dust from an 8-oz. (265-cm3) wide
