ANSI IEEE C57 12 56-1986 Standard Test Procedure for Thermal Evaluation of Insulation Systems for Ventilated Dry-Type Power and Distribution Transformers.pdf

1、ANSI/IEEE C57.12.56-1986An American National StandardIEEE Standard Test Procedure for Thermal Evaluation of Insulation Systems for Ventilated Dry-Type Power and Distribution TransformersSponsorTransformers Committee of theIEEE Power Engineering SocietySecretariatInstitute of Electrical and Electroni

2、cs EngineersNational Electrical Manufacturers AssociationApproved December 17, 1981IEEE Standards BoardApproved August 27, 1984American National Standards Institute Copyright 1986The Institute of Electrical and Electronics Engineers, Inc. 345 East 47th Street, New York, NY 10017, USANo part of this

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11、here the matter has previously received formal consideration.Comments on standards and requests for interpretations should be addressed to:Secretary, IEEE Standards Board345 East 47th StreetNew York, NY 10017USAiiiForeword(This Foreword is not a part of ANSI/IEEE C57.12.56-1986, IEEE Standard Test P

12、rocedure for Thermal Evaluation of InsulationSystems for Ventilated Dry-Type Power and Distribution Transformers.)This standard was developed to provide a method for evaluating insulation systems for ventilated dry-typetransformers with high-voltage ratings greater than 600 V. Since the procedures c

13、ontained herein are new, experiencefactors may require future revision.The working group that developed this standard used AIEE 65-1956, the Proposed Test for Thermal Evaluation ofVentilated Dry-Type Power and Distribution Transformers, as a starting point. New materials and coil-designtechniques ne

14、cessitated a revision of the procedure to recognize such factors as layer insulation, higher impulsewithstand capabilities, and new organic, high-temperature insulations. This standard describes methods that take thenew materials and processes into account.The working group was unable to define an e

15、xisting insulation system to use as a control for comparison with aninsulation system under test; therefore, an arbitrary extrapolation criteria of 40 000 h was selected for the evaluation.The working group urges the Dry-Type Transformer Industry to report results of tests using this standard to pro

16、vide abasis for future improvement.The working group considered aging under voltage stresses which might cause partial discharge but ruled it out sincepresent transformer designs are generally made to be as free of partial discharges as practical.The working group considered a vibration and shock pr

17、ocedure as one of the aging factors. So little information ispublished regarding the effects of vibration and shock in high-voltage insulation systems that it was impossible toinclude it in this standard. The working group urges the industry to report procedures and results of testing insulationsyst

18、ems with vibration and shock so that revisions of this standard may incorporate these factors, if they are found tobe significant.This standard relates voltage withstand end-point criteria to the impulse voltage distribution within the coil or to theinitial-voltage withstand of the coil. A relations

19、hip between impulse withstand of the insulation and short-term 60 Hzwithstand is identified so that 50/60 Hz testing of model coils is possible.Acknowledgement and thanks are extended to those who have so freely given their time and knowledge and haveconducted experimental work on which this standar

20、d is based.This standard was developed by a working group of the Dry-Type Transformer Subcommittee of the IEEETransformer Committee of the IEEE Power Engineering Society.At the time it approved this standard, the C57 Committee had the following membership:R. E. Uptegraff, Jr, Chair R.E. Ensign, Vice

21、 Chair R. G. Hansen, Secretary Organization Represented. Name of RepresentativeBonneville Power Administration. VacantElectric Light and Power Group N. DerwiankaR. L. EnsignI. H. KoponenB. F. SmithE. F. Villasuso, JrJ. P. Markery (Alt)Institute of Electrical and Electronics Engineers . J. V. Bonucch

22、iivO. ComptonJ. C. DuttonL. W. LongL. S. McCormickW. J. NeiswenderB. Stanleigh (Alt)National Electrical Manufacturers Association J. D. DouglassW. C. KendallK. R. LinsleyW. J. McNuttH. RobinM. SampahR. E. Uptegraff, JrR. J. Stahara (Alt)Naval Facilities Engineering Command .H. P. StickleyRural Elect

23、rification Administration.J. C. Arnold, JrTennessee Valley Authority. L. R. SmithUnderwriters Laboratories T. OGradyR. W. Seelbach (Alt)Water and Power Resources Service. F. W. Cook, SrWestern Area Power Administration. D. R. TorgersonThe personnel of the working group at the time of completion of t

24、his standard were as follows:G. H. Bowers, Chair B. F. AllenG. M. BellF. J. BrttE. J. HuberA.D. KlineM.L. ManningN.J. MeltonA.C. WurdackWhen the IEEE Standards Board approved this standard on December 17, 1981, it had the following membership:I. N. Howell, Jr, Chair Irving Kolodny, Vice Chair Sava I

25、. Sherr, Secretary G. Y. R. AllenJay ForsterFrank RosaJ. J. ArchambaultKurt GreeneRobert W. SeelbachJames H. BeallLoering M. JohnsonJay A. StewartJohn T. BoettgerJoseph L. KoepfingerWilliam E. VannahEdward ChelottiJohn E. MayVirginius N. Vaughan, JrEdward J. CohenDonald T. Michael *Art WallLen S. Co

26、reyJohn P. RiganatiRobert E. Weiler* Member emeritusvCLAUSE PAGE1. Introduction.11.1 Scope 11.2 Purpose. 11.3 References 11.4 Applicable Document in Preparation. 22. Basic Considerations.22.1 General. 22.2 Intent 22.3 Aging Factors. 22.4 Data Treatment. 33. Test Procedures .33.1 General. 33.2 Test M

27、odels 43.3 Screening 73.4 Test Cycles. 83.5 Temperature Aging 83.6 Humidity Conditioning 93.7 Dielectric Tests 94. Reporting.12Annex A (informative)13Annex B (informative) 15Copyright 1986 IEEE All Rights Reserved 1An American National StandardIEEE Standard Test Procedure for Thermal Evaluation of I

28、nsulation Systems for Ventilated Dry-Type Power and Distribution Transformers1. Introduction1.1 ScopeThis standard is intended to establish a uniform method for determining the temperature classification of ventilateddry-type power and distribution transformer insulation systems by test rather than

29、by chemical composition.These insulation systems are intended for use in transformers listed in ANSI C57.12.50-1981 11 and ANSIC57.12.51-1981 2, and whose highest voltages exceed nominal 600 V.NOTE In this standard, the term transformer shall be considered to mean ventilated dry-type transformer unl

30、ess qualified byother descriptive terms.1.2 PurposeThe purpose of this standard is to establish a uniform method1) For providing data for selection of the temperature classification of the insulation system2) For providing data which may be used as a basis for a loading guide3) For comparative evalu

31、ation of different insulation systems1.3 References1 ANSI C57.12.50-1981, American National standard Ventilated Dry-Type Distribution Transformers, 1 to 500 kVA,Single-Phase, and 15 to 500 kVA, Three-Phase, with High-Voltage 601 to 34 500 Volts, Low-Voltage 120 to 600 Volts2 2 ANSI C57.12.51-1981, A

32、merican National Standard Requirements for Ventilated Dry-Type Power Transformers,501 kVA and Larger, Three-Phase with High-Voltage 601 to 34 500 Volts, Low-Voltage 208Y/120 to 4160 Volts. 3 ANSI/ASTM D149-81, Standard Test Methods for Dielectric Breakdown Voltage and Dielectric Strength ofElectrica

33、l Insulating Materials at Commercial Power Frequencies.1The numbers in brackets correspond to those of the references listed in 1.3.2ANSI publications are available from the Sales Department, American National Standards Institute, 1430 Broadway, New York, NY 10018.2 Copyright 1986 IEEE All Rights Re

34、servedANSI/IEEE C57.12.56-1986 IEEE STANDARD TEST PROCEDURE FOR THERMAL EVALUATION FOR4 ANSI/IEEE C57.98-1986, IEEE Guide for Transformer Impulse Tests. 5 ANSI/IEEE Std 4-1978, IEEE Standard Techniques for High-Voltage Testing. 6 ASTM E104-51 (R1971), Standard Recommended Practice for Maintaining Co

35、nstant Relative Humidity by Meansof Aqueous Solutions.37 IEEE Std 1-1969, IEEE General Principles for Temperature Limits in the Rating of Electric Equipment.4 8 IEEE Std 101-1972, IEEE Guide for the Statistical Analysis of Thermal Life Test Data. 9 IEEE Std 101A-1974, Simplified Method for Calculati

36、on of the Regression Line (Appendix to IEEE Guide for theStatistical Analysis of Thermal Life Test Data, IEEE Std 101-1972). 10 MANNING, M. L. The Electrical Insulation Challenge for Dry-Type Transformers. Insulation/ Circuits, Sept1973, vol 19, no 10, pp 87-92.1.4 Applicable Document in Preparation

37、52. Basic Considerations2.1 GeneralTwo test methods are developed to provide a means for evaluating insulation systems as a function of thermal agingand are an extension of AIEE 65-1956,6 Thermal Evaluation of Ventilated Dry-Type Power and DistributionTransformers.One method is based on retention of

38、 a dielectric withstand voltage equal to a percentage of the initial 50/60 Hzdielectric withstand c capability of the test sample.The second method is based on the retention of the basic impulse insulation level7 by impulse testing, or by related10 50/60 Hz voltage withstand capability tests on mode

39、ls. See 3.7.2.2 IntentThe intent of these test methods is to have each component of the insulation system tested under conditions that are asnearly as possible the same as those in the actual transformer. Thus, each of the components is evaluated in accordancewith its actual function.2.3 Aging Facto

40、rsThe primary aging factors shall be temperature and time. Although the primary aging factors are temperature and time,the criterion of failure of these high-voltage insulation systems is assumed to be voltage related to the initial dielectricstrength or to the rated basic impulse voltage level. The

41、refore, the time to failure of the system is determined during the3ASTM publications are available from the American Society for Testing and Materials, 1916 Race St, Philadelphia, PA 19103.4IEEE publications are available from the Institute of Electrical and Electronics Engineers, Service Center, 44

42、5 Hoes Lane, Piscataway, NJ 08854.5When the following document is completed, approved, and published, it will become a part of this listing. IEEE Standards Project P745 (inpreparation), Guide for Conducting a Transient Analysis for Dry-Type Transformers.6AIEE 65-1956 was issued for trial use and may

43、 be used for general information.7Impulse tests are simulated in this method since transient response of models generally is not representative of that found in full size transformers.Copyright 1986 IEEE All Rights Reserved 3VENTILATED DRY-TYPE POWER AND DISTRIBUTION TRANSFORMERS ANSI/IEEE C57.12.56

44、-1986accelerated thermal aging by its ability to withstand prescribed proof test voltages applied after each thermal agingcycle. See 3.7.The Arrhenius relationship is the theoretical basis for this standard. Insulating systems which contain a largepercentage of inorganic material may not lend themse

45、lves to complete thermal evaluation by techniques based on theArrhenius relationship.Test methods specified in this test procedure are of an accelerated nature. Hence, an Arrhenius extrapolation of thetime to failure obtained at the test temperatures (log of life versus 1/absolute temperature) is re

46、quired to obtain thetemperature classification for normal operation. As the conditions of this accelerated testing are unusually severe,extrapolation of the data will indicate a shorter time to failure than will be obtained in actual service use. Due to thelack of a universally accepted standard tra

47、nsformer insulation system, it is not possible to compare insulation systemswith a standard system by way of the Arrhenius approach. It is expected that with the extended use of this testprocedure such a comparison can be made. Until then, a reference time of 40 000 h to failure shall be used as ami

48、nimum acceptable basis for establishing a temperature classification. See 4.1(3)(d).2.4 Data TreatmentTo ensure that valid results are obtained, free of bias and suitable for comparative studies, the test data shall be reducedstatistically and the results reported according to Section 4.Tests shall

49、be carried out in accordance with Method I described in 3.1.1 except that Method 2 described in 3.1.2 maybe used where applicable.Extrapolations indicated in Section 4 shall be applied only for failures occurring in the same part of the insulatingsystem. If failures occur in more than one part of the system, data for each mode of failure shall be treated separately.Similarly, the temperature classification shall be determined by separate extrapolation for each mode of failure and thelowest extrapolated temperature obtained shah be used as representin