1、The Institute of Electrical and Electronics Engineers, Inc.3 Park Avenue, New York, NY 10016-5997, USACopyright 2005 by the Institute of Electrical and Electronics Engineers, Inc.All rights reserved. Published 1998. Printed in the United States of America.IEEE is a registered trademark in the U.S. P
2、atent (978) 750-8400. Permission to photocopy portions of any individual standard for educational class-room use can also be obtained through the Copyright Clearance Center.Note: Attention is called to the possibility that implementation of this standard mayrequire use of subject matter covered by p
3、atent rights. By publication of this standard,no position is taken with respect to the existence or validity of any patent rights inconnection therewith. The IEEE shall not be responsible for identifying patents forwhich a license may be required by an IEEE standard or for conducting inquiries intot
4、he legal validity or scope of those patents that are brought to its attention.Copyright 1998 IEEE. All rights reserved.iiiIntroduction(This introduction is not part of IEEE Std C57.138, IEEE Recommended Practice for Routine Impulse Test for Distribu-tion Transformers.)William P. Lidinsky,Chair*Tony
5、Jeffree,Chair, Network Management Task Group*The following persons were on the balloting committee:*Member EmeritusEdward J. AdolphsonGeroge AllenJim AntweilerJames C. Arnold Jr.Donald E. BallardDavid A. Barnard William H. BartleyW. J. Bill BergmanWallace B. BinderAlain BollingerJohn D. BorstCharles
6、 V. BrownDavid S. BruckerMax A. CambreAlvaro CancinoJerry L. CorkranRobert DegeneffAlfonso M. DelgadoRandall L. DotsonBruce ForsythDudley L. GallowaySaurabh GhoshDonald A. GilliesRamsis S. GirgisRichard D. GrahamRobert L. GrunertMichael E. HaasKenneth S. HanusJack W. HarleyTommy W. HayesGeorge E. He
7、nry IIIPhilip J. HopkinsonJohn HuntCharles W. JohnsonAnthony J. JonnattiJoseph J. KellySheldon P. KennedyVladimir KhalinLawrence A. KirchnerBrian F. KlaponskiGary KleinAlexander D. KlineEgon KoenigAlvin KoppBarin KumarJohn P. LazarSingson LeeMark LovelessLarry A. LowdermilkDonald L. LoweThomas Lundq
8、uistWilliam A. MaguireCharles MandevilleRichard P. MarekJohn W. MatthewsW. E. Bill McCainL. Bruce McClungBen McConnellCharles J. McMillenNigel P. McQuinC. Patrick McShaneSam P. MehtaJoe MelansonSam MichaelDaleep C. MohlaW. E. Gene MorehartDaniel H. MulkeyChuck R. MurrayR. J. MusilCarl G. NiemannLarr
9、y NunneryPaul OrehekGerald A. PaivaDhiru S. PatelWesley F. PattersonPaulette A. PayneCarlos PeixotoThomas PekarekMark D. PerkinsLinden PierceR. Leon PlasterBertrand PoulinTom A. PrevostChris A. RobbinsJohn R. RossettiGerry W. RoweHazairin SamaulahMahesh P. SampatVallamkonda S. N. SankarSubhas Sarkar
10、Rick SawyerVic ShenoyStephen ShullHyeong Jin SimTarkeshwar SinghStephen D. SmithJames E. SmithJerry W. Smith Steven L. SnyderRonald J. StaharaRon W. StonerJohn C. Sullivan Malcolm V. ThadenJames A. ThompsonAl TrautSubash C. TuliJoseph J. VaschakRobert A. VeitchLoren B. WagenaarRalph D. WakeamBarry H
11、. WardD. W. WhitleyAlan L. WilksWilliam G. WimmerDavid WoodcockivCopyright 1998 IEEE. All rights reserved.When the IEEE-SA Standards Board approved this standard on 19 March 1998, it had the followingmembership:John R. Rossetti,ChairNoelle D. HumenickIEEE Standards Project EditorJames C. Arnold Jr.D
12、onald E. BallardCharles V. BrownJerry L. CorkranJohn C. CrouseReto H. FauschGeorge E. Henry IIILarry L. HilsenbeckRichard A. HollingsworthPhilip J. HopkinsonBrian F. KlaponskiGeorge K. KrauseLarry A. LowdermilkArthur MoldenHarold R. MooreCharles J. McMillenGerald A. PaivaFrancois RuellandJames E. Sm
13、ithStephen D. SmithMichael A. ThorntonRalph D. WakeamAlan L. WilksCopyright 1998 IEEE. All rights reserved.vContents1. Overview 11.1 Scope 11.2 Purpose. 12. References 13. General test procedures 24. Fault detection methods . 25. Circuits for routine impulse testing 35.1 Impulse wave shape . 35.2 Tr
14、ansformer connections . 45.3 Grounding considerations 156. Neutral current detection circuit 156.1 Ground current circuit 156.2 Neutral-impedance circuit 166.3 CT circuit . 177. Failure detection methods 187.1 Detection requirements 187.2 Comparison of wave shapes. 197.3 Automatic failure detection
15、197.4 Special considerations 298. Verification of detector sensitivity. 29Annex A (informative) Distribution transformer voltage distribution and impulse fault detection 32Copyright 1998 IEEE. All rights reserved.1IEEE Recommended Practice for Routine Impulse Test for Distribution Transformers1. Ove
16、rview1.1 Scope This recommended practice covers routine impulse tests performed on distribution transformers, as requiredin IEEE Std C57.12.00-1993, and described in subclause 10.4 of IEEE Std C57.12.90-1993.Distribution transformers covered by this recommended practice are liquid-immersed, single-
17、and three-phase overhead-type up to 500 kVA; single-phase pad-mounted compartmental-type and underground-typeup to 167 kVA; three-phase pad-mounted compartmental-type and underground-type up to 2500 kVA. Thesetransformers are covered by IEEE Std C57.12.20-1988 through IEEE Std C57.12.26-1992.This re
18、commended practice covers only those aspects of impulse testing that are specic to routine testing ofdistribution transformers. For more thorough coverage of impulse testing of transformers in general, theIEEE Guide for Transformer Impulse Tests, IEEE Std C57.98-1993, should be consulted.1.2 Purpose
19、This recommended practice is to assist manufacturers of distribution transformers in the setup and operationof a routine impulse test, and to assist distribution transformer users and purchasers in understanding theroutine impulse test and how it differs from design tests.2. ReferencesWhen the follo
20、wing ANSI/IEEE standards and guides referred to in this recommended practice are super-seded by a general revision approved by the American National Standards Institute, the latest revision shallapply.This recommended practice shall be used in conjunction with the following publications:IEEE Std 4-1
21、995, IEEE Standard Techniques for High-Voltage Testing.11IEEE publications are available from the Institute of Electrical and Electronics Engineers, 445 Hoes Lane, P.O. Box 1331, Piscataway,NJ 08855-1331, USA.IEEEStd C57.138-1998 IEEE RECOMMENDED PRACTICE FOR ROUTINE2Copyright 1998 IEEE. All rights
22、reserved.IEEE Std 1122-1987, IEEE Standard for Digital Recorders for Measurements in High-Voltage ImpulseTests.IEEE Std C57.12.00-1993, IEEE Standard General Requirements for Liquid-Immersed Distribution, Power,and Regulating Transformers.IEEE Std C57.12.20-1988, Requirements for Overhead-Type Distr
23、ibution Transformers, 500 kVA andSmaller: High Voltage 34 500 Volts and Below; Low Voltage 7970/13 800 Y Volts and Below.IEEE Std C57.12.22-1989, American National Standard for TransformersPad-Mounted, Compartmental-Type, Self-Cooled, Three-Phase Distribution Transformers with High-Voltage Bushings,
24、 2500 kVA andSmaller: High Voltage, 34 500 Grd Y/19 920 Volts and Below; Low Voltage, 480 Volts and BelowRequire-ments.IEEE Std C57.12.23-1992, IEEE Standard for TransformersUnderground-Type, Self-Cooled, Single-Phase Distribution Transformers with Separable, Insulated, High-Voltage Connectors; High
25、 Voltage (24 940Grd Y/14 400 Volts and Below) and Low Voltage (240/120 V; 167 kVA and Smaller).IEEE Std C57.12.25-1990, American National Standard for TransformersPad-Mounted, Compartmental-Type, Self-Cooled, Single-Phase Distribution Transformers with Separable Insulated High-Voltage Connec-tors: H
26、igh Voltage, 34 500 Grd Y/19 920 Volts and Below; Low Voltage, 240/120 Volts; 167 kVA andSmallerRequirements.IEEE Std C57.12.26-1992, IEEE Standard for Pad-Mounted, Compartmental-Type, Self-Cooled, Three-Phase Distribution Transformers for Use with Separable Insulated High-Voltage Connectors (34 500
27、 Grd Y/19 920 Volts and Below; 2500 kVA and Smaller).IEEE Std C57.12.90-1993, IEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regu-lating Transformers and IEEE Guide for Short Circuit Testing of Distribution and Power Transformers.IEEE Std C57.98-1993, IEEE Guide for Transformer
28、 Impulse Tests.3. General test proceduresFor information on the correct test sequence when impulse voltage tests are to be performed, refer to IEEEStd C57.12.90-1993.The routine impulse test normally consists of one reduced and one full-wave impulse, or two full-waveimpulses. The full-wave impulses
29、are at a crest voltage equal to the rated BIL of the terminal being tested.Chopped wave tests are not included in the routine test. Each line terminal of a winding rated above 600 Vthat is brought out through a suitable bushing is to be tested. For transformers that have two or more wind-ings rated
30、above 600 V, all line terminals of each such winding are to be tested. Neutral terminals, and termi-nals of windings rated 600 V and below, are not to be tested in the routine impulse test. 4. Fault detection methods Routine impulse testing of distribution transformers as specied in IEEE Std C57.12.
31、90-1993, subclause10.4 requires that the test equipment demonstrate the ability to detect a single-turn fault. A typical fault canbe simulated by placing a shorted turn of wire around the core leg and over the coil of a core and coil assem-bly. Methods of providing such detection sensitivity are dis
32、cussed in the sections that follow and in theAnnex that accompanies this document.IEEEIMPULSE TEST FOR DISTRIBUTION TRANSFORMERS Std C57.138-1998Copyright 1998 IEEE. All rights reserved.35. Circuits for routine impulse testingThis test is normally performed on the production line as part of the rout
33、ine quality control tests. As such,the routine impulse test may be performed on a large number of transformers using a test with automatedfailure detection. The failure detection system must be sensitive enough to detect all failures, including asingle-turn fault.For a general description of the rou
34、tine impulse test circuit see the lightning impulse test circuit described inIEEE Std C57.98-1993. Subclause 5.2 of this document describes the recommended circuit hook-ups forvarious test pieces.5.1 Impulse wave shapeThe impulse wave shape to be used for routine impulse testing of distribution tran
35、sformers is the ANSI/IEEEstandard 1.2 50 ms full-wave lightning impulse described in IEEE Std 4-1995 and IEEE Std C57.98-1993.Descriptions of approved techniques and equipment for measurement of the applied impulse wave can alsobe found in IEEE Std C57.98-1993.5.1.1 Test voltagesThe full-wave impuls
36、es shall have a crest value equal to the rated BIL of the terminal being tested. Thereduced full-wave impulses shall have crest values equal to 50%70% of rated BIL.5.1.2 Tolerances Tolerances for impulse test voltages and wave shapes are given in ANSI/IEEE Std C57.12.90-1993. It mustbe noted, howeve
37、r, that it is sometimes not practical to make circuit modications to achieve a wave shapewithin tolerance for every transformer being tested. If the impulse equipment is sized to test the requiredrange of transformers and the wave shaping circuit is designed to produce a standard impulse on an avera
38、getransformer, the test circuit will generally be adequate for making a valid routine impulse test on the fullrange of transformers.Every effort should be made to ensure that the applied wave shape complies with the standard in the area ofthe voltage peak. That is, oscillations on the voltage peak s
39、hould be no greater than 5% of the crest voltage.If the frequency of those oscillations is greater than 0.5 MHz or the duration of overshoot is less than 1 ms,the peak voltage value is determined from a mean curve through the oscillation(s). (Refer to IEEE Std 4-1995.)5.1.3 Effects of impulse genera
40、tor loading The impulse equipment used for routine impulse tests on distribution transformers must satisfy a differentset of requirements than equipment used for design impulse testing in laboratory environments. Due to thelarge number of tests that must be performed on a typical production line, im
41、pulse circuit parameters can notbe modied for each test by changing component values or circuit connections. The impulse circuit, as indi-cated by Figure 1, should be designed such that it will supply the proper impulse wave shape for all units tobe tested without the need to make changes. Depending
42、 on the mix of units to be tested on a single produc-tion line, such a design may be difcult or uneconomical to achieve. A few guidelines on impulse circuitdesign for production line testing are given in the following paragraphs.IEEEStd C57.138-1998 IEEE RECOMMENDED PRACTICE FOR ROUTINE4Copyright 19
43、98 IEEE. All rights reserved.A large majority of distribution transformers presently produced have a fairly high impedance at the primaryterminals when excited by impulse frequencies. As a result the load presented to the impulse generator whenperforming routine impulse tests on distribution transfo
44、rmers often has only a small effect on the voltagewave shape produced by a well-designed impulse generator. Some transformers however will have a largeeffect, especially on an impulse generator whose design was not carefully considered.To provide a more consistent time to half value one can use larg
45、er stage capacitors and lower value parallelor tail resistors. At the same time, a reduction in the value of front or series resistors will reduce the waveshape distorting effects of variations in load current. Be aware however that reducing the value of front resis-tors will also reduce front time
46、and may increase oscillations near the wave crest.As load capacitance changes, so does the impulse front time, often making it difcult to obtain the speciedvalue. The front time is generally determined by the impulse circuit inductances and the RC time constantformed by the front resistors and the c
47、ircuit capacitances. The two capacitances having the greatest effect arethe preload or wave shaping capacitor (C2 in Figure 1), and the effective load capacitance. Since the preloadcapacitor is in parallel with the load, using a preload capacitance that is much greater than the capacitance ofthe loa
48、d reduces the sensitivity of front time to changes in load capacitance. The stage capacitance is inseries with the load and preload capacitances and is typically much larger than the preload capacitance. Assuch, the choice of stage capacitance usually has little effect on front time. Lead inductance
49、s and internalgenerator inductances can, when large enough, have a signicant effect on front time. For this and other rea-sons it is always a good idea to keep all series inductances as low as possible through the use of low-inductive components and short testing leads.Using good grounding practices also improves the consistency of impulse wave shape and amplitude. For ageneral discussion on recommended grounding techniques, see section 5 of IEEE Std C57.98-1993.5.2 Transformer connectionsThe required connections for routine impulse tests on distribution
