1、Designation: D 923 07Standard Practices forSampling Electrical Insulating Liquids1This standard is issued under the fixed designation D 923; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in par
2、entheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 These practices cover sampling of new electrical insu-lating liqui
3、ds including oils, askarels, silicones, syntheticliquids, and natural ester insulating liquids as well as thoseinsulating liquids in service or subsequent to service in cables,transformers, circuit breakers, and other electrical apparatus.These practices apply to liquids having a viscosity of less t
4、han6.476 3 10-4m2/s (540 cSt) at 40C (104F).1.2 Representative samples of electrical insulating liquidsare taken for test specimens so that the quality pertinent to theiruse may be determined. The quality in different portions of agiven container, or the average quality of the whole bulk maybe ascer
5、tained if desired.1.3 The values stated in SI units are regarded as the standardwhere applicable. Inch pound units are used where there is noSI equivalent.1.4 These practices also include special techniques anddevices for sampling for dissolved gases-in-oil (DGA)(D 3612), water (D 1533) and particle
6、s (D 6786).1.5 For ease of use, this document has been indexed asfollows:Section TitleSection/ParagraphMandatory Conditions and General Information Section 5Description of Sampling Devices and Containers Section 6,Annex A1,Appendix X2Most Frequently Used Sampling Techniques for Electri-cal Apparatus
7、Collecting Samples from Electrical Equipment Using Bottlesand CansSection 7,Appendix X1,Appendix X2Collecting Samples from Electrical Equipment Using GlassSyringes (DGA and Water Analysis)Section 8Collecting Samples from Electrical Equipment UsingStainless Steel Cylinders (DGA and Water Analysis)Sec
8、tion 9Sampling of Cans, Drums, Tank Cars, Tank Trucks andSmall Electrical EquipmentSampling Using the Dip-Type Device (drum thief) Section 10Section TitleSection/ParagraphSampling Using the Pressure-Type Device Section 11,Annex A1.1Sampling Using the Tank Car-Type Device Section 12,Annex A1.2Samplin
9、g Cable FeedersMandatory Conditions Section 13General Considerations Section 14Sampling Using the Manifold-Type Device Section 15,Annex A1.3Cleaning, Preparation, Storage, and Handling of Sam-pling ContainersSection 16Storage, Packaging and Shipping of Samples Section 17Cleaning and Storage of Sampl
10、ing Devices Section 18Sample Information Section 19Mandatory InformationConstruction of Sampling Devices Annex A1Determination of Electrical Apparatus Temperature Appendix X1Sample Container Types Appendix X21.6 Handle askarels containing polychlorinated biphenyls(PCBs) according to federal and loca
11、l regulations existing forthat country. For example, the federal regulations concerningPCBs in the United States can be found in 40 CFR Part 761.1.7 Properly contain, package and dispose of any liquid ormaterial resulting from the use of these practices in a mannerthat is in accordance with local an
12、d state regulations specific tothe country in which the samples are taken.1.8 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
13、 the applica-bility of regulatory limitations prior to use. Specific warningstatements are given in 1.6, 1.7, Section 5, 10.1, 13.2, 15.2.3,Section 16, and 18.2. These practices involve close contactwith the electrical insulating liquids being sampled as well asliquids and other materials used to cl
14、ean the sampling tools anddevices. When required, or as a matter of diligence to personalsafety, use personal protective equipment (PPE).1These practices are under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquids and Gases and is the direct responsibility of Subcom-mittee D27.0
15、7 on Physical Test.Current edition approved July 15, 2007. Published September 2007. Originallyapproved in 1947. Last previous edition approved in 1997 as D 923 07.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2. Referenced Documen
16、ts2.1 ASTM Standards:2D 1533 Test Method for Water in Insulating Liquids byCoulometric Karl Fischer TitrationD 1933 Specification for Nitrogen Gas as an ElectricalInsulating MaterialD 3612 Test Method for Analysis of Gases Dissolved inElectrical Insulating Oil by Gas ChromatographyD 4057 Practice fo
17、r Manual Sampling of Petroleum andPetroleum ProductsD 6786 Test Method for Particle Count in Mineral Insulat-ing Oil Using Automatic Optical Particle Counters3. Terminology3.1 Definition:3.1.1 samplingthe obtaining of that amount of a materialwhich is adequate for making the required tests and which
18、 isrepresentative of that portion of the material from which it istaken.3.1.1.1 DiscussionIn most cases the detection of contami-nants that are not ordinarily dispersed uniformly through theliquid being sampled, such as water or solid particles, neces-sitates taking samples at specific locations whe
19、re the contami-nants are likely to be found. For a liquid having a relativedensity (specific gravity) less than one, water and some otherimpurities are most likely to be found on or near the bottom. Inthe case of a liquid having a specific gravity greater than one,some of these impurities are most l
20、ikely to be found on or nearthe surface.4. Significance and Use4.1 Accurate sampling, whether of the complete contents oronly parts thereof, is extremely important from the standpointof evaluating the quality of the liquid insulant sampled.Obviously, examination of a test specimen that, because ofca
21、reless sampling procedure or contamination in samplingequipment, is not directly representative, leads to erroneousconclusions concerning quality and in addition results in a lossof time, effort, and expense in securing, transporting, andtesting the sample.4.2 A study of gases and moisture contained
22、 in insulatingoils from transformers and other electrical power apparatus canfrequently give an early indication of abnormal behavior of theapparatus, and may indicate appropriate action be taken on theequipment before it suffers greater damage. Specific gas andmoisture content can be determined fro
23、m oil sampled for thispurpose.5. Mandatory Conditions and General Information5.1 Mandatory Conditions when Sampling Electrical Appa-ratus:5.1.1 Energized electrical apparatus being sampled musthave a positive pressure at the sampling outlet, so as not tointroduce an air bubble into the apparatus dur
24、ing the samplingprocess. Refer to 7.2.5.1.2 Do not draw samples from any energized electricalequipment with a small volume of oil, especially those thatrequire the addition of oil to maintain the electric strength ofthe insulation system. If the proper level or existing level cannot be accurately de
25、termined do not proceed.5.1.3 Maintain the insulating fluid within the electricalapparatus being sampled at a level that will not reduce theelectric strength of the insulation system.5.1.4 Do not sample electrical apparatus if only a drain plugis provided, as it would be difficult to control the flo
26、w.5.1.5 Do not draw samples from energized instrumenttransformers such as CTs and PTs.5.2 General Information:5.2.1 Take and handle samples or test specimens in such amanner as to avoid the loss or gain of properties for which theyare being tested. Some tests are greatly affected by minutetraces of
27、impurities, and it is imperative that utmost precau-tions be taken to prevent contamination when obtainingsamples. Due to the hygroscopic tendency of insulating liquids,it is important to minimize exposure to the atmosphere of thesample being taken.5.2.2 Take a sufficient quantity of liquid as a sam
28、ple tocover the requirements of the respective tests to be made. Makereference to the procedures governing these tests to ascertainthe quantity of liquid for each test specimen and the number oftest specimens required.5.2.3 When samples are to be taken the temperature of theliquid should be equal to
29、 or greater than the temperature of thesurrounding air in order to minimize the possibility of con-densed moisture from the air being absorbed by the liquidduring the sampling process, particularly in a humid atmo-sphere.5.2.4 When taking samples of liquid from large storagetanks, transformers, oil-
30、circuit breakers, gravity-fed reservoirson oil-filled cable feeders, and other electrical equipment, theelectrical equipment drain valve is usually adequate. However,when high relative humidity conditions exist and it is desired toobtain samples through a closed system, the manifold in Fig.10 is rec
31、ommended.5.3 General Information when Sampling Electrical Appara-tus:5.3.1 All non-hermetically sealed equipment, filled withinsulating liquid having a relative density (specific gravity) lessthan 1, should be provided with the sampling outlet located atthe bottom of the tank so that bottom samples
32、of the oil may beobtained.5.3.2 All non-hermetically sealed equipment, filled withinsulating liquid having a relative density (specific gravity)greater than 1, should be provided with the sampling outletlocated at the top of the tank at the 25C (77F) liquid level sothat a top sample of the liquid ma
33、y be obtained.5.3.3 When make-up liquid is added to any piece ofelectrical equipment or the liquid is filtered, allow sufficient2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informatio
34、n, refer to the standards Document Summary page onthe ASTM website.D923072time to lapse to allow for complete mixing before sampling inorder that a representative sample is obtained.5.3.4 If samples or test specimens must be taken when theliquid temperature is below 0C (32F), high water contentmay n
35、ot be detected because of the formation of ice. Ice is aconcern in both energized and de-energized electrical appara-tus where insulating oil-filled compartments operate at tem-peratures below freezing, such as some tap changer compart-ments and circuit breaker tanks.5.3.5 When retrieving samples fr
36、om electrical apparatus,record the apparatus temperature (C) along with the identifi-cation information as required by Section 19. Knowledge ofthe apparatus temperature (C) at the time of sampling aids inthe interpretation of results from certain tests (Refer to Appen-dix X1).5.4 General Information
37、 when Sampling Liquid-FilledTanks, Drums, Tank Trucks, Tank Cars and other SimilarContainers:5.4.1 When sampling large outdoor tanks, tank trucks, tankcars, and de-energized electrical equipment the temperature ofthe liquid to be sampled may be colder than the surroundingair. On such an occasion, de
38、termine and report the temperatureof the liquid and air as well as the relative humidity with theresults of tests. It is undesirable to collect samples that areexposed to the atmosphere when the relative humidity exceeds50 % or under conditions of rain or snow.5.4.2 Allow containers of new liquid to
39、 remain undisturbedfor at least 8 h before samples or test specimens are taken. Insome instances, such as in the case of tank cars, it is notpractical to wait this prescribed length of time, and samples forroutine tests may be taken after the liquid has remainedundisturbed for as long a period as pr
40、acticable. For refereetests, allow the full 8-h waiting period to elapse before takingsamples or test specimens. Repeat samples or test specimensfrom tank cars may be taken without waiting an additional 8 h.5.4.3 Unless otherwise specified, take samples of insulatingliquids having a relative density
41、 (specific gravity) of less than1 from the bottom of the liquid container. For drums, cans,small tanks, etc., design the sampling device so that the sampleis obtained a distance of 3 mm from the bottom of thecontainer, while for large tanks, tank trucks and tank cars, thedistance is within 13 mm of
42、the bottom.5.4.4 Unless otherwise specified, take samples of insulatingliquids having a relative density (specific gravity) of greaterthan 1 from the surface layer of the liquid.6. Description of Sampling Devices and Containers6.1 Devices suitable for withdrawing samples of liquid fromcontainers, el
43、ectrical equipment, cable feeders, and cable jointsare described below, shown in Figs. 110 and the Annex, anddiscussed in Appendix X1.6.2 Electrical Equipment Sampling Drain Valve or PortUsed for taking top or bottom samples from energized orde-energized electrical apparatus. This device is especial
44、lysuitable when collecting samples in a glass jar, metal can, orother suitable containers as described in this section.6.3 Glass BottleUsed for securing and storing the sample.Amber or clear (see Notes 1 and 2) and may be eitherglass-stoppered or fitted with screw caps having a pulp-boardliner faced
45、 with tin or aluminum foil, or with a suitableoil-resistant plastic such as polyethylene, polytetrafluoroethyl-ene (PTFE) or fluoro-elastomers. Do not use any incompatiblenatural or synthetic rubber materials. Must meet the require-ments of Section 16. (See Appendix X2.)NOTE 1While amber-colored gla
46、ss bottles are used for storingsamples as protection against light, clear glass bottles afford better visualinspection of the samples or test specimens for impurities such as waterand foreign particles. Take samples that are to be subjected to referee testsin new amber-colored containers that have b
47、een cleaned as described inSection 16.6.4 Other Bottle or Can Containers (Note 2)Used forsecuring and storing the sample. May be constructed from asuitable oil-resistant plastic such as high-density polyethylene(HDPE) (do not use for long term storage when water contentis to be determined), or metal
48、 cans such as those made fromaluminum, stainless steel, other appropriate metal, or PTFElined. Metals cans are to be constructed as fully extruded,pressed seams or welded seams. Solder seams may leave aresidue that will contaminate the sample. Screw caps andclosures must meet the requirements of 6.3
49、. (See AppendixX2.)NOTE 2It is recommended to retrieve samples for DGA and wateranalysis using only syringes or stainless steel cylinders. If bottles and cansare used, gases that are to be measured in the DGA analysis can easilyescape from these types of containers. Alternatively, environmental gasescan become entrained into the sample. Both situations can alter the resultssignificantly.6.5 Glass SyringeThe device shown in Fig. 1 must be ofa suitable size terminated with a Luer lock fitting to which isattached a three-way stopcock. It is used for taking samplesusuall
