1、Designation: D923 15Standard Practices forSampling Electrical Insulating Liquids1This standard is issued under the fixed designation D923; 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 paren
2、theses indicates the year of last reapproval. Asuperscript 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 These practices cover sampling of new electrical insu-lating liq
3、uids 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
4、 than6.476 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)(D3612), water (D1533) and particles
6、(D6786).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 forElectrical ApparatusColle
7、cting Samples from Electrical Equipment Using Bottlesand CansSection 7,Appendix X1,Appendix X2Collecting Samples from Electrical Equipment Using GlassSyringes (DGA and Water Analysis)Section 8Section TitleSection/ParagraphCollecting Samples from Electrical Equipment UsingStainless Steel Cylinders (D
8、GA and Water Analysis)Section 9Sampling of Cans, Drums, Tank Cars, Tank Trucks andSmall Electrical EquipmentSampling Using the Dip-Type Device (drum thief) Section 10Sampling Using the Pressure-Type Device Section 11,Annex A1.1Sampling Using the Tank Car-Type Device Section 12,Annex A1.2Sampling Cab
9、le FeedersMandatory Conditions Section 13General Considerations Section 14Sampling Using the Manifold-Type Device Section 15,Annex A1.3Cleaning, Preparation, Storage, and Handling ofSampling ContainersSection 16Storage, Packaging and Shipping of Samples Section 17Cleaning and Storage of Sampling Dev
10、ices 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 local regul
11、ations 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 and state
12、 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 the ap
13、plica-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 clean the
14、 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 are the direct responsibility ofSubcommittee D27.07 on Phy
15、sical Test.Current edition approved Oct. 1, 2015. Published October 2015. Originallyapproved in 1947. Last previous edition approved in 2007 as D923 07. DOI:10.1520/D0923-15.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12. Reference
16、d Documents2.1 ASTM Standards:2D1533 Test Method for Water in Insulating Liquids byCoulometric Karl Fischer TitrationD1933 Specification for Nitrogen Gas as an Electrical Insu-lating MaterialD3612 Test Method for Analysis of Gases Dissolved inElectrical Insulating Oil by Gas ChromatographyD4057 Prac
17、tice for Manual Sampling of Petroleum andPetroleum ProductsD6786 Test Method for Particle Count in Mineral InsulatingOil Using Automatic Optical Particle Counters3. Terminology3.1 Definitions:3.1.1 samplingthe obtaining of that amount of a materialwhich is adequate for making the required tests and
18、which 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 location
19、s where 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 m
20、ost likely 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
21、 ofcareless 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 cont
22、ained 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 determine
23、d from 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 apparatu
24、s during 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 accurate
25、ly determined 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 th
26、e flow.5.1.5 Do not draw samples from energized instrumenttransformers such as CTs and PTs.5.1.6 Do not draw samples from an energized switch or thecable termination compartment of network transformers.5.2 General Information:5.2.1 Take and handle samples or test specimens in such amanner as to avoi
27、d the loss or gain of properties for which theyare being tested. Some tests are greatly affected by minutetraces of 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
28、 to minimize exposure to the atmosphere of thesample being taken.5.2.2 Take a sufficient quantity of liquid as a sample 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
29、 number oftest specimens required.5.2.3 When samples are to be taken the temperature of theliquid should be equal to 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,
30、 particularly in a humid atmo-sphere.5.2.4 When taking samples of liquid from large storagetanks, transformers, oil-circuit breakers, gravity-fed reservoirson oil-filled cable feeders, and other electrical equipment, theelectrical equipment drain valve is usually adequate. However,when high relative
31、 humidity conditions exist and it is desired toobtain samples through a closed system, the manifold in Fig.10 is recommended.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 gravi
32、ty) lessthan 1, should be provided with the sampling outlet located atthe bottom of the tank so that bottom samples 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
33、the sampling outletlocated at the top of the tank at the 25C (77F) liquid level sothat a top sample of the liquid may be obtained.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informat
34、ion, refer to the standards Document Summary page onthe ASTM website.D923 1525.3.3 When make-up liquid is added to any piece ofelectrical equipment or the liquid is filtered, allow sufficienttime to lapse to allow for complete mixing before sampling inorder that a representative sample is obtained.5
35、.3.4 If samples or test specimens must be taken when theliquid temperature is below 0C (32F), high water contentmay not 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-peratu
36、res below freezing, such as some tap changer compart-ments and circuit breaker tanks.5.3.5 When retrieving samples from 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 tim
37、e of sampling aids inthe interpretation of results from certain tests (Refer to Appen-dix X1).5.4 General Information 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 electric
38、al equipment the temperature ofthe liquid to be sampled may be colder than the surroundingair. On such an occasion, determine 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 atmosph
39、ere when the relative humidity exceeds50 % or under conditions of rain or snow.5.4.2 Allow containers of new liquid to 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
40、of time, and samples forroutine tests may be taken after the liquid has remainedundisturbed for as long a period as practicable. 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 w
41、aiting an additional 8 h.5.4.3 Unless otherwise specified, take samples of insulatingliquids having a relative density (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
42、 mm from the bottom of thecontainer, while for large tanks, tank trucks and tank cars, thedistance is within 13 mm of 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. D
43、escription of Sampling Devices and Containers6.1 Devices suitable for withdrawing samples of liquid fromcontainers, electrical 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
44、 PortUsed for taking top or bottom samples from energized orde-energized electrical apparatus. This device is especiallysuitable 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
45、or clear (see Notes 1 and 2) and may be eitherglass-stoppered or fitted with screw caps having a pulp-boardliner faced 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
46、synthetic rubber materials. Must meet the require-ments of Section 16. (See Appendix X2.)NOTE 1While amber-colored glass 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 wateran
47、d foreign particles. Take samples that are to be subjected to referee testsin new amber-colored containers that have been 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
48、 as high-density polyethylene(HDPE) (do not use for long term storage when water contentis to be determined), or metal 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. Sold
49、er seams may leave aresidue that will contaminate the sample. Screw caps andclosures must meet the requirements of 6.3. (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 suita
