IEEE 1048-2003 en Guide for Protective Grounding of Power Lines《电力线的保护接地》.pdf

1、IEEE Std 1048-2003(Revision of IEEE Std 1048-1990)IEEE Standards1048TMIEEE Guide for Protective Grounding ofPower LinesPublished by The Institute of Electrical and Electronics Engineers, Inc.3 Park Avenue, New York, NY 10016-5997, USA26 September 2003IEEE Power Engineering SocietySponsored by theTra

2、nsmission +1 978 750 8400. Permission to photocopy portions of any individual standard for educationalclassroom use can also be obtained through the Copyright Clearance Center.Note: Attention is called to the possibility that implementation of this standard may require use of subject mat-ter covered

3、 by patent rights. By publication of this standard, no position is taken with respect to the existence orvalidity of any patent rights in connection therewith. The IEEE shall not be responsible for identifying patentsfor which a license may be required by an IEEE standard or for conducting inquiries

4、 into the legal validity orscope of those patents that are brought to its attention.iv Copyright 2003 IEEE. All rights reserved.Introduction(This introduction is not part of IEEE Std 1048-2003, IEEE Guide for Protective Grounding of Power Lines.)Protective grounding methods have often not kept pace

5、with their increasing importance in work safety asthe available fault current magnitudes grow, sometimes to as high as 100 kA, and as right-of-ways becomemore crowded with heavily loaded circuits, leading to growing problems of electric or magnetic induction.This guide has compiled state-of-the-art

6、information on protective grounding practices employed by powerutilities in North America.The revision of the guide was undertaken to add information on the electrical hazards related to electric util-ity vehicles working adjacent to power lines. Electrostatic induction develops a voltage on the veh

7、icle, itsmagnitude depending upon the vehicles insulation from ground, the separation distance, and the voltageand current on the adjacent line. The hazards may include both a transient discharge current as the vehicle isgrounded through a persons body and a steady-state capacitive current that may

8、flow through the vehicle.The revision discusses the advantages of isolating the worksite by barricading the vehicle to protect thepublic from the electrical hazards.The revision also includes factors important in sizing protective grounds. These factors are based on areview of current practices, tec

9、hnical information, and safety criteria. The factors are intended to protectelectrical workers during work on de-energized transmission and distribution lines. The primary purpose of factors in sizing protective grounds is to ensure that protective grounds utilized dur-ing de-energized work on trans

10、mission and distribution lines are sized to adequately protect workers frominjury or electrocution. Protective ground sizing is required for the maximum magnitude and duration ofcurrent that may flow in a grounding system at a worksite. The current may be of short duration from acci-dental energizat

11、ion of the line or may be due to continuous current from magnetic induction by nearby ener-gized circuits.This revision addresses the size of protective grounds to carry fault currents or induced current at the work-site for the full duration of current. Determination of fault current magnitude cons

12、idering the ac and dc offsetcomponents and the effect of X/R (X is reactance and R is resistance) ratios is discussed. Primary and backuprelaying times are discussed because both items are important considerations for sizing protective grounds.The determination of currents induced by nearby energize

13、d circuits is also discussed as an essential consid-eration for sizing protective grounds.The material requirements for protective grounding sets are discussed in detail. Recommended materials,ratings, component design and shape, jacket material, resistance, mechanical stress considerations, anddeta

14、ils of multiple grounding systems are also covered.Finally, a discussion of the practical use of protective grounds is covered. The preferred practice is to use asingle protective ground at a worksite. Because a single protective ground cannot always be accomplished, itis permissible to parallel mor

15、e than one grounding cable. The precautions required for multiple protectivegrounds used in parallel are discussed. This guide concludes with a presentation of in-service maintenance,inspection, and testing guidelines.This guide was developed through the collaborative effort of an international grou

16、p of volunteers withexpertise in many disciplines. While this guide represents a consensus among this volunteer group, it is notthe only view on the issues addressed herein. As with any guidance, use of this guide and the procedures andpositions herein does not provide proof of or guarantee safety.

17、Use and compliance with this IEEE guide arewholly voluntary.Copyright 2003 IEEE. All rights reserved. vParticipantsAt the time this revised guide was completed, the Working Group on Guide for Protective Grounding ofPower Lines had the following membership:Gernot K. Brandt, ChairThe following members

18、 of the balloting committee voted on this revised guide. Balloters may have voted forapproval, disapproval, or abstention.When the IEEE-SA Standards Board approved this revised guide on 20 March 2003, it had the followingmembership:Don Wright, ChairHoward M. Frazier, Vice ChairJudith Gorman, Secreta

19、ry*Member EmeritusAlso included are the following nonvoting IEEE-SA Standards Board liaisons:Alan Cookson, NIST RepresentativeSatish K. Aggarwal, NRC RepresentativeSavoula AmanatidisIEEE Standards Managing EditorDave BellowsKenneth J. BrownJ. F. DoeringBrian ErgaHarold FoxDonald A. GilliesPaul W. Ho

20、tteJ. Ernest JonesHarry J. KientzClayton KingG. R. KiserDonald E. KoonceJ. David MitchellDennis ReisingerGeorge E. StinnettJames R. TomaseskiRoy W. AlexanderJames E. ApplequistR. Allen BernstorfNelson G. BingelGernot K. BrandtVernon L. ChartierJames F. ChristensenFrank A. DenbrockNicholas J. DeSanti

21、sJohn FarringtonFrank FerracaneMarcel FortinGeorge GelaDonald A. GilliesRichard W. HenselAndrew Robert HilemanGeorge G. KaradyRobert O. KlugeNestor KolcioDonald E. KoonceGeorge N. LesterJ. David MitchellDaleep C. MohlaYakov MotlisAbdul M. MousaRonald J. OedemannMark OstendorpRobert G. OswaldCarlos O

22、 PeixotoRobert C. PetersRadhakrishna V. RebbapragadaThomas J. RozekDonald SandellNeil P. SchmidtDoug ShermanDaniel J. WardH. Stephen BergerJoseph A. BruderBob DavisRichard DeBlasioJulian Forster*Toshio FukudaArnold M. GreenspanRaymond HapemanDonald N. HeirmanLaura HitchcockRichard H. HulettAnant Ku

23、mar JainLowell G. JohnsonJoseph L. Koepfinger*Tom McGeanSteve M. MillsDaleep C. MohlaWilliam J. MoylanPaul NikolichGary S. RobinsonMalcolm V. ThadenGeoffrey O. ThompsonDoug ToppingHoward L. Wolfmanvi Copyright 2003 IEEE. All rights reserved.Contents1. Overview 11.1 Scope 11.2 Purpose. 12. References

24、 13. Definitions . 24. Principles . 54.1 Introduction 54.2 General. 54.3 Fault currents . 104.4 Induction (coupling) 134.5 Lightning 155. Rating of grounding sets 155.1 Ground set components . 155.2 Grounding cable size . 176. Grounding practices. 216.1 Introduction 216.2 Theoretical considerations

25、 226.3 Distribution line grounding 287. Power line construction . 288. Work procedures 288.1 Introduction 288.2 Voltage detection methods. 288.3 Advantages and disadvantages of voltage detectors 308.4 Cleaning conductor and ground connections. 319. Grounding procedures 329.1 Preliminary. 329.2 Inst

26、allation procedure 329.3 Removing grounds. 3310. Vehicles and equipmentmethods of protectionworkers and public . 3410.1 Methods . 3410.2 Vehicle grounding 3411. Maintenance. 3511.1 Inspection and maintenance of protective grounds 3511.2 Testing . 35Copyright 2003 IEEE. All rights reserved. vii12. Gr

27、ound electrodes 3712.1 Pole grounds 3712.2 System neutral 3712.3 OHGW . 3712.4 Ground rods . 3712.5 Measuring devices . 37Annex A (informative) Bibliography 39Copyright 2003 IEEE. All rights reserved. 1IEEE Guide for Protective Grounding of Power Lines1. Overview1.1 ScopeThis document provides guide

28、lines for grounding methods to protect workers and the public from voltagesthat might develop in a jobsite during de-energized maintenance of overhead transmission and distributionlines.1.2 PurposeThis document is intended to provide guidance for protective grounding in jobsites during de-energizedm

29、aintenance of power lines. The primary purpose of protective grounding is to limit the voltage differencebetween any two accessible points at the worksite to an acceptable value. As an IEEE guide, the purpose ofthis document is to suggest approaches for protective grounding. This guide does not have

30、 mandatoryrequirements. Following the suggestions in this guide helps to mitigate risks, and users should take all rea-sonable steps necessary to minimize risks during de-energized maintenance of power lines.2. ReferencesThis guide should be used in conjunction with the following publications. When

31、the following standards aresuperseded by an approved revision, the revision shall apply.ASC C2-1997, National Electric Safety Code(NESC).1, 2ASTM B263-1999, Standard Test Method for Determination of Cross-Sectional Area of StrandedConductors.31National Electrical Safety Code and NESC are both regist

32、ered trademarks and service marks of the Institute of Electrical and Electron-ics Engineers, Inc.2The NESC is available from the Institute of Electrical and Electronics Engineers, Inc., 445 Hoes Lane, P.O. Box 1331, Piscataway, NJ08855-1331 US (http:/standards.ieee.org).3ASTM publications are availa

33、ble from the Sales Department of the American Society for Testing and Materials, 1916 Race Street,Philadelphia, PA 19103.IEEEStd 1048-2003 IEEE GUIDE FOR 2 Copyright 2003 IEEE. All rights reserved.ASTM F855-1997, Standard Specifications for Temporary Protective Grounds to be Used on De-EnergizedElec

34、trical Power Lines and Equipment.IEEE Std 516-1995, IEEE Guide for Maintenance Methods on Energized Power Lines.4, 5IEEE Std 524a-1993, IEEE Guide to Grounding During the Installation of Overhead Transmission LineConductors: Supplement to IEEE Std 524-1992 (Reaff 1997), IEEE Guide to the Installatio

35、n of OverheadTransmission Line Conductors.OSHA 29 CFR 1910.269, Occupational Safety and Health Standard: Electric Power Generation, Transmis-sion, and DistributionSubpart R: Special Industries.63. DefinitionsTerminology for equipment and procedures associated with the installation of temporary prote

36、ctive ground-ing systems varies widely throughout the industry. Therefore, definitions have been included to provide acorrelation between the terminology used in this guide and industry synonyms. Note that the synonyms areterms commonly used, although many are not necessarily good usage and should n

37、ot be taken as equivalentsto the guide terminology.3.1 accessible voltage drop: Voltage difference between any two points accessible to workers at theworksite.3.2 bonded: The mechanical interconnection of conductive parts to maintain a common electrical potential.(See: bonding, The Authoritative Dic

38、tionary of IEEE Standards Terms, Seventh Edition B77.) Syn: con-nected.3.3 bracket grounding: A grounding method where temporary ground sets are installed on both sides of theworksite. Syn: adjacent structure grounding.3.4 bundle, two-conductor, three-conductor, four-conductor, and multiconductor: O

39、ne phase of a cir-cuit consisting of more than one conductor. Each conductor of the phase is referred to as a subconductor. Atwo-conductor bundle has two subconductors per phase. These may be arranged in a vertical or horizontalconfiguration. Syn: twin-bundle; tri-bundle; quad-bundle.NOTEThe support

40、ing hardware may not maintain an effective bond between the conductors during faults.3.5 clamp, temporary grounding: A device used in making a temporary connection between the groundingcable and the ground bus or grounding electrode and between the grounding cable and the transmission ordistribution

41、 facility that is being grounded.3.6 cluster bar and cluster support: A terminal that is temporarily attached to the structure to support (itmay serve to establish an equipotential zone) and provide a bar that will accommodate at least two ground-ing clamps and may have terminals to accommodate grou

42、nding cables.4The IEEE standards or products referred to in Clause 2 are trademarks owned by the Institute of Electrical and Electronics Engineers,Incorporated.5IEEE publications are available from the Institute of Electrical and Electronics Engineers, Inc., 445 Hoes Lane, P.O. Box 1331, Piscat-away

43、 NJ 08855-1331, USA (http:/standards.ieee.org/).6OSHA publications are available from the U.S. Department of Labor/OSHA, OSHA Publications, P.O. Box 37535, Washington, DC20013-7535 USA (http:/www.osha.gov/).7The numbers in brackets correspond to the numbers of the bibliography in Annex A.IEEEPROTEC

44、TIVE GROUNDING OF POWER LINES Std 1048-2003Copyright 2003 IEEE. All rights reserved. 33.7 combination ground: A grounding method where temporary ground sets are installed on structures onboth sides of the worksite, and with a ground set on the phase being worked on at the worksite.3.8 conductor: A w

45、ire or combination of wires stranded together not insulated from one another, suitablefor carrying an electric current. However, it may be bare or insulated. Syn: cable; wire.3.9 de-energized: Free from any electrical connection to a source of potential difference and from electriccharge; not having

46、 a potential different from that of the earth.The term is used only with reference to current-carrying parts that are sometimes energized (alive). (See:dead, The Authoritative Dictionary B7.)3.10 electric field induction (capacitive coupling): The process of generating voltages or currents toground

47、or both in a conductive object or electric circuit by means of time-varying electric fields.3.11 electromagnetic field induction (electromagnetic coupling): The induction process that includesboth electric and magnetic fields and generates a circulating current between two grounded ends of a linedue

48、 to the proximity of an adjacent or close energized and loaded line.3.12 energized: Electrically connected to a source of potential difference, or electrically charged to have apotential different from that of the earth in the vicinity. (See: alive, The Authoritative Dictionary B7.) Syn:alive; curre

49、nt-carrying; hot; live.3.13 equipotential: An identical state of electrical potential for two or more items. For the purposes of pro-tective grounding, a near identical state of electrical potential.3.14 fault (components): A physical condition that causes a device, a component, or an element to fail toperform in a required manner.3.15 fault (current): A current that flows from one conductor to ground or to another conductor owing to anabnormal connection (including an arc) between the two.3.16 ground or grounded: A conducting connection, whether intentional o