1、Designation:D152415(Reapproved 2022)Standard Test Method forVisual Examination of Used Electrical Insulating Liquids inthe Field1This standard is issued under the fixed designation D1524;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revisio
2、n,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 for visual examination is applicable toelectricalinsulatingliquidsthathavebeenusedintransfor
3、mers,oil circuit breakers,or other electrical apparatusas insulating or cooling media,or both.1.2 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,health,and enviro
4、nmental practices and deter-mine the applicability of regulatory limitations prior to use.1.3 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standard
5、s,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D1500 Test Method for ASTM Color of Petroleum Products(ASTM Color Scale)D2129 Test Method for Color of Clear Electrical InsulatingLiquids(Platinum-C
6、obalt Scale)3.Summary of Test Method3.1 The condition of the test specimen is estimated byobservation of cloudiness,foreign particles,or suspendedmatter in the sample by reflected light.4.Significance and Use4.1 By use of this test method and Test Methods D1500 orD2129 the color and condition of a t
7、est specimen of electricalinsulating liquid may be estimated during a field inspection,thus assisting in the decision as to whether or not the sampleshould be sent to a central laboratory for full evaluation.Cloudiness,particles of insulation,products of metal corrosion,or other undesirable suspende
8、d materials,as well as anyunusual change in color may be detected.5.Apparatus5.1 Sample ContainerThe sample vessel from a colorcomparitor,or a container in which light can be projected fromthe bottom into the sample.5.2 LightA light source such as a pen light with a No.222bulb.5.3 ClothPhotographers
9、 focusing cloth.6.Procedure6.1 Tyndall Beam ExaminationProject a narrow focusedlight beam from the pen light upward through the samplecontainer,using the photographic focusing cloth to excludeextraneous light.Carefully examine the test specimen bymeans of this light.A test specimen of good insulatin
10、g liquidwill appear clean and bright.Haziness or cloudiness usuallydenotes moisture in suspension or sludge.If the dielectricstrength is satisfactory,the cloudiness may be caused byoxidation products,in which case the neutralization numberwill probably be high and the interfacial tension low.Particl
11、esof metals,insulation,carbon,and other matter will show upvery markedly by reflected light.Report the electrical insulat-ing liquid as failing the test if the appearance of any conditionother than clear and bright is observed.7.Report7.1 Report the following information:7.1.1 Type of insulating liq
12、uid,7.1.2 Pass or fail,and the description of any deviation fromperfectly clear and bright,7.1.3 Evidence of sediment or free water,7.1.4 Approximate temperature of the liquid at the time thetest specimen was taken,and7.1.5 Approximate temperature of the liquid at time ofobservation,if other than at
13、 room temperature.1This test method is under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquids and Gases and is the direct responsibility of Subcom-mittee D27.07 on Physical Tests.Current edition approved July 1,2022.Published August 2022.Originallyapproved in 1968.Last previous
14、 edition approved in 2015 as D1524 15.DOI:10.1520/D1524-15R22.2For 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.Copy
15、right 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 theDevelopment of International
16、Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.18.Precision and Bias8.1 It is not practical to specify the precision and bias of thistest method because this is a rapid field examination to screentest specimens for further testing.8.2 An interlaboratory investigation was conducted in 1968to support this test method.The results of this investigationwere first reported in January 1969.39.Keywords9.1Tyndell beam effect;visual ex