1、IEEE Std C37.91-2008(Revision ofIEEE Std C37.91-2000)IEEE Guide for Protecting PowerTransformersIEEE3 Park Avenue New York, NY 10016-5997, USA30 May 2008IEEE Power Engineering SocietySponsored by thePower System Relaying CommitteeC37.91TMIEEE Std C37.91-2008 (Revision of IEEE Std C37.91-2000) IEEE G
2、uide for Protecting Power Transformers Sponsor Power System Relaying Committee of the IEEE Power Engineering Society Approved 31 January 2008 IEEE-SA Standards Board Abstract: This guide is intended to provide protection engineers and other readers with guidelines for protecting three-phase power tr
3、ansformers of more than 5 MVA rated capacity and operating at voltages exceeding 10 kV. In some cases, a user may apply the techniques described in this guide for protecting transformers of less than 5 MVA ratings or operating at voltages less than 10 kV. Information to assist protection engineers i
4、n applying properly relays and other devices to protect transformers used in transmission and distribution systems is provided in this guide. General philosophy, practical applications, and economic considerations involved in power transformer protection are discussed. Emphasis is placed on practica
5、l applications. Types of faults in transformers are described. Technical problems with the protection systems, including the behavior of current transformers during system faults, are discussed. Associated problems, such as fault clearing and reenergization, are discussed as well. Keywords: analysis
6、 of dissolved gases in transformer oil, application of multifunction relays for transformer protection, differential protection, failures of transformers, overcurrent protection, protection of phase-shifting transformers, protection of transformers, volts-per-hertz protection The Institute of Electr
7、ical and Electronics Engineers, Inc. 3 Park Avenue, New York, NY 10016-5997, USA Copyright 2008 by the Institute of Electrical and Electronics Engineers, Inc. All rights reserved. Published 30 May 2008. Printed in the United States of America. IEEE is a registered trademark in the U.S. Patent +1 978
8、 750 8400. Permission to photocopy portions of any individual standard for educational classroom use can also be obtained through the Copyright Clearance Center. iv Copyright 2008 IEEE. All rights reserved. Introduction This introduction is not part of IEEE Std C37.91-2008, IEEE Guide for Protecting
9、 Power Transformers. This document is a revision of IEEE Std C37.91-2000, IEEE Guide for Protective Relay Applications to Power Transformers. This guide is intended to provide aid in the effective application of relays and other devices for the protection of power transformers. In this revision, sev
10、eral areas have been improved. Most notably: Several clauses have been revised. Differential protection has been augmented to include the techniques used in numerical relays. Techniques now being used in numerical relays, such as harmonic restraint and harmonic blocking, wave shape recognition, low-
11、current detection, and direct-current blocking methods, are included. An example of the relay blocking logic is included. New figures have been included to reflect the practice of connecting all current transformers (CTs) in wye configuration when numerical relays are used. The possibility of CT sat
12、uration when faults occur outside the protection zone of differential relays and the current does not flow through the differential zone is explained. Protection of transformers for faults in the grounded wye-connected windings has been expanded to include the use of restricted earth-fault relays. T
13、he practice of remote tripping of circuit breakers to protect transformers used to tap transmission and subtransmission lines is explained. The clause on gas analysis has been revised to bring it in line with the current practices. The use of rate of change of total dissolved combustible gases is in
14、corporated. New annexes have been created. Annex B lists the transformer failure statistics collected by the Canadian Electrical Association. Annex C outlines the procedure for setting relays for protecting three transformers. The first transformer is a step-up transformer, the second transformer is
15、 a network autotransformer, and the third transformer is used for supplying energy to a distribution system. Annex D describes the need for monitoring current on the high-voltage and low-voltage windings, when automatic tap changing is used, for determining the hot-spot temperature of a transformer.
16、 Annex E outlines the methods that are used in differential relays for compensating for the phase shift in delta-wye transformers. Notice to users Laws and regulations Users of these documents should consult all applicable laws and regulations. Compliance with the provisions of this standard does no
17、t imply compliance to any applicable regulatory requirements. Implementers of the standard are responsible for observing or referring to the applicable regulatory requirements. IEEE does not, by the publication of its standards, intend to urge action that is not in compliance with applicable laws, a
18、nd these documents may not be construed as doing so. v Copyright 2008 IEEE. All rights reserved. Copyrights This document is copyrighted by the IEEE. It is made available for a wide variety of both public and private uses. These include both use, by reference, in laws and regulations, and use in pri
19、vate self-regulation, standardization, and the promotion of engineering practices and methods. By making this document available for use and adoption by public authorities and private users, the IEEE does not waive any rights in copyright to this document. Updating of IEEE documents Users of IEEE st
20、andards should be aware that these documents may be superseded at any time by the issuance of new editions or may be amended from time to time through the issuance of amendments, corrigenda, or errata. An official IEEE document at any point in time consists of the current edition of the document tog
21、ether with any amendments, corrigenda, or errata then in effect. In order to determine whether a given document is the current edition and whether it has been amended through the issuance of amendments, corrigenda, or errata, visit the IEEE Standards Association Web site at http:/ieeexplore.ieee.org
22、/xpl.standards.jsp, or contact the IEEE at the address listed previously. For more information about the IEEE Standards Association or the IEEE standards development process, visit the IEEE-SA Web site at http:/standards.ieee.org. Errata Errata, if any, for this and all other standards can be access
23、ed at the following URL: http:/standards.ieee.org/reading/ieee/updates/errata/index.html. Users are encouraged to check this URL for errata periodically. Interpretations Current interpretations can be accessed at the following URL: http:/standards.ieee.org/reading/ieee/interp/ index.html. Patents At
24、tention is called to the possibility that implementation of this guide may require use of subject matter covered by patent rights. By publication of this guide, no position is taken with respect to the existence or validity of any patent rights in connection therewith. The IEEE is not responsible fo
25、r identifying Essential Patent Claims for which a license may be required, for conducting inquiries into the legal validity or scope of Patents Claims or determining whether any licensing terms or conditions provided in connection with submission of a Letter of Assurance, if any, or in any licensing
26、 agreements are reasonable or non-discriminatory. Users of this guide are expressly advised that determination of the validity of any patent rights, and the risk of infringement of such rights, is entirely their own responsibility. Further information may be obtained from the IEEE Standards Associat
27、ion. vi Copyright 2008 IEEE. All rights reserved. Participants At the time this guide was submitted to the IEEE-SA Standards Board for approval, the Protection of Transformers Against Faults and Abnormal Conditions Working Group had the following membership: Mohindar S. Sachdev, Chair Pratap G. Myso
28、re, Vice Chair Robert Beresh Simon Chano Arvind K. S. Choudhary Albert N. Darlington Paul R. Elkin Walter A. Elmore Jalal Gohari Roger A. Hedding Michael Jensen Jerry A. Jodice Bill Kennedy Sungsoo Kim Mukesh Nagpal James K. Niemira Bruce A. Pickett Vittal V. Rebbapragada Murari M. Saha Sinan Saygin
29、 Mark Schroeder Michael Thompson Demetrios A. Tziouvaras Joe T. Uchiyama Don K. Ware Murty Yalla Tony Yip Richard Young The Working Group thanks the balloters, especially those who provided comments that have definitely helped in improving the usefulness of this guide. The Working Group is especiall
30、y grateful to Jefferey Benach, Gary Hoffman, and Peter Meyer for their written contributions provided for this guide. The following members of the individual balloting committee voted on this guide. Balloters may have voted for approval, disapproval, or abstention. William J. Ackerman Steven Alexand
31、erson Stan Arnot Gary E. Arntson Ali Al Awazi Peter Balma Paul Barnhart David C. Beach Philip Beaumont Thomas R. Beckwith Jeffrey D. Benach Gabriel Benmouyal Robert Beresh W. J. Bill Bergman Steven Bezner Wallace Binder Thomas Blackburn Thomas Blair William Bloethe Oscar E. Bolado Paul Boman Stuart
32、Bouchey Steven Brockschink Chris Brooks Kent W. Brown Gustavo Brunello William Byrd Eldridge Byron Antonio Cardoso Robert Carruth James Case Simon Chano Arvind K. S. Chaudhary Weijen Chen Bill Chiu Mark Clark Stephen P. Conrad Tommy Cooper James Cornelison Luis Coronado Randall P. Crellin John Crous
33、e Russ C. Dantzler Stephen Dare Albert N. Darlington Eddie L. Davis J. Disciullo Kevin E. Donahoe Carlo Donati Michael Dood Randall Dotson Paul Drum Donald Dunn Paul R. Elkin Fred Elliott Walter A. Elmore Ahmed F. Elneweihi Gary Engmann Kenneth Fodero Joseph Foldi Marcel Fortin Fredric A. Friend Jam
34、es Gardner Frank J. Gerleve Jeffrey Gilbert Jalal Gohari Manuel Gonzalez William T. Gordon James Graham Stephen Grier Charles Grose Randall Groves Ajit K. Gwal Robert Hartgrove Roger A. Hedding Charles F. Henville Gary Heuston Gary Hoffman Jerry Hohn David A. Horvath Dennis Horwitz James D. Huddlest
35、on R. Jackson Jerry A. Jodice Anders L. Johnson Gerald Johnson James Jones Lars Juhlin Innocent Kamwa Bogdan Z. Kasztenny Steven A. Kell Peter J. Kemp Gael Kennedy Sheldon Kennedy W. O. Kennedy Morteza Khodaie Joseph L. Koepfinger Boris Kogan David W. Krause Edward Krizauskas Jim Kulchisky Saumen Ku
36、ndu vii Copyright 2008 IEEE. All rights reserved. Chung-Yiu Lam Stephen Lambert Raluca Lascu Gerald Lee Jason Jy-Shung Lin Albert Livshitz Federico Lopez William Lowe G. Luri Jinxi Ma Bruce Mackie Vahid Madani O. Malik Keith N. Malmedal J. Dennis Marlow John W. Matthews Omar Mazzoni William McBride
37、Walter McCannon Michael McDonald Michael J. Meisinger Peter Meyer Gary Michel Dean Miller William J. Mindick Karl N. Mortensen Brian Mugalian Jerry Murphy Bruce Muschlitz Pratap G. Mysore George Nail Krste Najdenkoski Bradley D. Nelson Arthur Neubauer Michael Newman James K. Niemira Joe Nims James M
38、. OBrien Donald Parker Carlos A. O. Peixoto Robert Pettigrew Alvaro Portillo Paulette Payne Powell Iulian Profir Jeffrey Ray Ryland Revelle Michael Roberts Charles Rogers John Rossetti Mohindar S. Sachdev Miriam P. Sanders Dinesh Pranathy Sankarakurup Steven Sano Thomas Schossig Tony L. Seegers Greg
39、ory Sessler Lubomir H. Sevov Devki Sharma Michael A. Shirven Tarlochan S. Sidhu Hyeong J. Sim Mark S. Simon Tarkeshwar Singh Veselin Skendzic Douglas Smith James E. Smith Jerry Smith Devendra K. Soni John Spare Brian D. Sparling Charles Sufana Richard Taylor John Tengdin S. Thamilarasan Michael Thom
40、pson T. P. Traub Michael Tucker Demetrios A. Tziouvaras Joe T. Uchiyama Loren B. Wagenaar Daniel Ward Joe D. Watson William Waudby Kenneth White Thomas E. Wiedman James Wilson Murty Yalla Ray Young Richard Young Theodore Zeiss Karl V. Zimmerman Donald W. Zipse Ahmed Zobaa When the IEEE-SA Standards
41、Board approved this guide on 31 January 2008, it had the following membership: Robert M. Grow, Chair Thomas Prevost, Vice Chair Steve Mills, Past Chair Judith Gorman, Secretary Victor Berman Richard DeBlasio Andy Drozd Mark Epstein Alexander Gelman William Goldbach Arnie Greenspan Ken Hanus Jim Hugh
42、es Richard Hulett Young Kyun Kim Joseph L. Koepfinger* John Kulick David J. Law Glenn Parsons Ron Petersen Chuck Powers Narayanan Ramachandran Jon Walter Rosdahl Anne-Marie Sahazizian Malcolm Thaden Howard Wolfman Don Wright *Member Emeritus Also included are the following nonvoting IEEE-SA Standard
43、s Board liaisons: Satish K. Aggarwal, NRC Representative Michael H. Kelley, NIST Representative Lisa Perry IEEE Standards Project Editor Matthew J. Ceglia IEEE Standards Program Manager, Technical Program Development viii Copyright 2008 IEEE. All rights reserved. Contents 1. Overview 1 1.1 Scope . 1
44、 1.2 Purpose 1 2. Normative references 1 3. Definitions 2 4. Device numbers 3 5. Philosophy and economic considerations . 3 6. Types of failures in transformers 4 7. Relay currents . 5 7.1 Minimum internal faults 5 7.2 Maximum internal faults 6 7.3 Performance of current transformers . 6 7.4 Reasons
45、 for mismatch 8 8. Electrical detection of faults . 10 8.1 Fuse protection and self-powered resettable fault interrupters 11 8.2 Differential protection . 12 8.3 Overcurrent relay protection 29 8.4 Ground-fault protection . 31 8.5 Fault detection for special-purpose transformers . 36 8.6 Backup and
46、external fault protection . 41 8.7 Temperature relays 43 8.8 Miscellaneous relays 44 9. Mechanical detection of faults 44 9.1 Gas accumulator relay . 44 9.2 Gas detector relay 44 9.3 Pressure relays . 45 10. Thermal detection of abnormalities 47 10.1 Thermal relays for winding temperature 47 10.2 Ot
47、her means of thermal protection 49 ix Copyright 2008 IEEE. All rights reserved. 11. Fault clearing 51 11.1 Relay tripping circuits 52 11.2 Circuit breakers 52 11.3 Tripping of remote circuit breakers . 52 11.4 Circuit switcher 54 11.5 Fuses 54 11.6 Self-powered resettable fault interrupters 55 12. R
48、eenergizing practice . 55 13. Gas analysis 56 13.1 Level of TDCG and rate of change of TDCG approach 57 13.2 Ratio of gases approach . 58 14. Special protective schemes . 59 14.1 Overall unit generator differential . 59 14.2 Unit transformer of three-legged core form type . 61 14.3 Grounding transfo
49、rmer inside the main transformer differential zone 61 14.4 Unbalanced voltage protection for wye-connected, three-legged, core-type transformers 62 14.5 Differential protection of single-phase transformers connected in three-phase banks . 63 14.6 Differential protection of a bank of three single-phase autotransformers with delta tertiary . 65 14.7 Differential protection of single-phase transformers in a three-phase bank with a spare transformer 66 15. Other considerations . 67 Annex A (informative) Application of the transformer through-fault-current d
