1、Published by theInstitute of Electrical andElectronics Engineers, Inc.142IEEE Recommended Practice forGrounding ofIndustrial andCommercial PowerSystemsIEEE Std 142-2007(Revision ofIEEE Std 142-1991)IEEEBOOKgreenIEEE Std 142-2007(Revision ofIEEE Std 142-1991)IEEE Recommended Practice for Grounding of
2、 Industrial and Commercial Power SystemsSponsor Power Systems Engineering Committeeof theIEEE Industry Applications SocietyApproved 7 June 2007IEEE-SA Standards BoardThe Institute of Electrical and Electronics Engineers, Inc.3 Park Avenue, New York, NY 10016-5997, USACopyright 2007 by the Institute
3、of Electrical and Electronics Engineers, Inc.All rights reserved. Published 30 November 2007. Printed in the United States of America.IEEE is a registered trademark in the U.S. Patent +1 978 750 8400. Permission to photocopy portions ofany individual standard for educationalclassroom use can also be
4、 obtained through the CopyrightClearance Center.iv Copyright 2007 IEEE. All rights reserved.IntroductionThis book is a revision of IEEE Std 142-1991, the IEEE Green Book.Thisrecommended practice has served electrical engineers seeking electrical system groundinginformation since the first edition in
5、 1956. It reflects the experience and sound judgmentof a working group made up of engineers active in the design and operation of electricalsystems for industrial and commercial power systems. Notice to usersErrataErrata, if any, for this and all other standards can be accessed at the following URL:
6、http:/standards.ieee.org/reading/ieee/updates/errata/index.html. Users are encouraged tocheck this URL for errata periodically.InterpretationsCurrent interpretations can be accessed at the following URL: http:/standards.ieee.org/reading/ieee/interp/index.html.PatentsAttention is called to the possib
7、ility that implementation of this standard may require useof subject matter covered by patent rights. By publication of this standard, no position istaken with respect to the existence or validity of any patent rights in connection therewith.The IEEE shall not be responsible for identifying patents
8、or patent applications for whicha license may be required to implement an IEEE standard or for conducting inquiries intothe legal validity or scope of those patents that are brought to its attention.This introduction is not part of IEEE Std 142-2007, IEEE Recommended Practice for Groundingof Industr
9、ial and Commercial Power Systems.Copyright 2007 IEEE. All rights reserved. vParticipantsAt the time this standard was submitted to the IEEE-SA Standards Board for approval, theWorking Group had the following membership:Elliot Rappaport, ChairDaleep C. Mohla, Vice ChairChapter 1: System groundingDona
10、ld W. Zipseand Gene Strycula,Co-chairsChapter 2: Equipment groundingElliot Rappaport,ChairChapter 3: Static and lightning protection groundingDonald McCullough II andDonald W. Zipse, Co-chairsChapter 4: Connection to earthKen Michaels,ChairChapter 5: Electronic equipment groundingThomas Baldwin, Cha
11、irThe following members of the individual balloting committee voted on this standard.Balloters may have voted for approval, disapproval, or abstention.Larry AyerV. BaschBaldwin BridgerWilliam BushM. ButkiewiczThomas M. GruzsM. JerathDon O. KovalT. David MillsNeil NicholsMelvin K. SandersLynn F. Saun
12、dersSrinivasa I.VenugopaianMarcos AndradeRichard BeckerW. J. (Bill) BergmanThomas BlairWilliam BloetheStuart BoucheyBaldwin BridgerFrederick BrockhurstMark BushnellKeith ChowDonald ColaberardinoStephen P. ConradTerry ConradJames DalyStephen DareGuru Dutt DhingraGary Di TroiaGary DonnerRandall Dotson
13、Neal DowlingDonald DunnRandall GrovesThomas M. GruzsPaul HamerRobert HoeraufDarin HuculRobert InghamDavid W. JacksonJoseph JancauskasYuri KhersonskyRobert KonnikDon O. KovalSaumen KunduStephen R. LambertBlane LeuschnerJason LinMichael LowensteinRichard LoydGregory LuriKeith MalmedalWilliam McCoyDona
14、ld McCullough IIWilliam MoylanMichael NewmanNeil NicholsGreg NolanT. W. OlsenGregory OlsonLorraine PaddenKostas PervolarakisPaul PillitteriPercy PoolLouie PowellElliot RappaportRadhakrishna RebbapragadaMichael RobertsMelvin K. SandersSteven SanoRobert SchuergerRobert SeitzMichael ShirvenH. Jin Simvi
15、 Copyright 2007 IEEE. All rights reserved.When the IEEE-SA Standards Board approved this standard on 7 June 2007, it had thefollowing membership:Steve M. Mills,ChairRobert M. Gown, Vice ChairDon Wright,Past ChairJudith Gorman,Secretary*Member EmeritusAlso included are the following nonvoting IEEE-SA
16、 Standards Board liaisons:Satish K. Aggarwal, NRC RepresentativeAlan H. Cookson, NIST RepresentativeDon MessinaIEEE Standards Program Manager, Document DevelopmentPatricia A. Gerdon IEEE Standards Program Manager, Technical Program DevelopmentDan EvansJay FischerH. Landis Floyd IIMarcel FortinCarl F
17、redericksEdgar GalyonTravis GriffithMark McGranaghanJohn MerandoJames MichalecGary MichelT. David MillsJames MitchemCharles MorseAbdul MousaDavid SmithRobert SmithDevendra SoniPeter SutherlandJames WilsonLarry YoungDonald W. ZipseRichard DeBlasioAlex GelmanWilliam R. GoldbachArnold M. GreenspanJoann
18、a N. GueninJulian Forster*Kenneth S. HanusWilliam B. HopfRichard H. HulettHermann KochJoseph L. Koepfinger*John KulickDavid J. LawGlenn ParsonsRonald C. PetersenTom A. PrevostNarayanan RamachandranGreg RattaRobby RobsonAnne-Marie SahaziziaVirginia C. SulzbergerMalcolm V. ThadenRichard L. TownsendHow
19、ard L. WolfmanCopyright 2007 IEEE. All rights reserved. viiContentsChapter 1System grounding . 11.1 Introduction11.2 Definitions21.3 Purposes of system grounding .41.4 Methods of system neutral grounding51.5 Obtaining the system neutral .221.6 Location of system grounding points.281.7 Grounding of i
20、ndustrial and commercial generators .381.8 Autotransformers .481.9 System grounding for uninterruptible power systems .531.10 Portable mining equipment supply systems.571.11 Creation of stray currents and potentials .601.12 Avoiding common-mode noise621.13 Limiting transferred earth potentials631.14
21、 “Resonantly” produced voltages641.15 Grounding of dc power systems 661.16 Normative references.701.17 Bibliography 73Chapter 2Equipment grounding 752.1 Basic objectives .752.2 Fundamental concepts772.3 Equipment grounding as influenced by type of use.952.4 Outdoor open-frame substations952.5 Unit s
22、ubstations992.6 Installations serving heavy portable electric machinery1002.7 Interior wiring systems 1042.8 Interior unit substations and switching centers1102.9 Utilization equipment.1112.10 Normative references.1142.11 Bibliography 116Chapter 3Static and lightning protection grounding. 1193.1 Int
23、roduction1193.2 Static grounding.1193.3 Lightning protection grounding .1403.4 Normative references.1563.5 Bibliography 159viii Copyright 2007 IEEE. All rights reserved.Chapter 4Connection to earth. 1614.1 Resistance to earth .1614.2 Ground electrodes 1694.3 Methods and techniques of construction174
24、4.4 Measurement of resistance to earth1764.5 Normative references.182Chapter 5Electronic equipment grounding. 1875.1 Introduction1875.2 Definitions1875.3 History of computer grounding1885.4 System or equipment to be grounded.1905.5 Grounding electronic equipment1915.6 Effects of internal rectifiers
25、in computers2005.7 Grounding of shields2015.8 Interference from radio frequencies.2045.9 Case histories .2055.10 Normative references.2075.11 Bibliography 208Index . 211Copyright 2007 IEEE. All rights reserved. 1IEEE Recommended Practice for Grounding of Industrial and Commercial Power SystemsChapte
26、r 1System grounding1.1 Introduction1.1.1 OverviewThis chapter provides recommended procedures for the system grounding of industrialand commercial power systems, and the proper selection and application of groundingimpedances. Special cases of system grounding are also addressed for generators,unint
27、erruptible power supplies (UPS), portable mining equipment, and multi-voltagesystems.1.1.2 GeneralGrounding of an electrical system is a decision that must be faced sometime by mostengineers charged with planning or modifying electrical distribution. Grounding in someform is generally recommended, a
28、lthough there are certain exceptions. Several methodsand criteria exist for system grounding; each has its own purpose. It is the intention of this chapter to assist the engineer in making decisions on the subjectby presenting basic reasons for grounding or not grounding and by reviewing generalprac
29、tices and methods of system grounding. The practices set forth herein are primarily applicable to industrial power systems thatdistribute and utilize power at medium or low voltage, usually within a smallergeographical area than is covered by a utility. Where distances or power levels may dictate ci
30、rcuitry and equipment similar to a utility,consideration of utility practices is warranted. However, restrictions of the NationalElectrical Code(NEC), NFPA 701particular needs of service and the experience andtraining of the workforce should also be considered. 1Information on references can be foun
31、d in 1.16.IEEEStd 142-2007 CHAPTER 12 Copyright 2007 IEEE. All rights reserved.Where an industrial power system includes power-generating equipment, the reasons forgrounding these components may be the same as those for grounding similar componentsof public utility systems. The methods of grounding
32、would generally be similar under likeconditions of service. However, in the industrial setting, conditions of service may bealtered by the following:a) Location within the power system b) Individual generator characteristics c) Manufacturing process requirementsAll of these may affect grounding deci
33、sions. The NEC, sponsored by the National Fire Protection Association, contains regulationspertaining to system and equipment grounding applicable to industrial, commercial, andspecial occupancy facilities. These rules are considered minimum requirements for theprotection of life and property and sh
34、ould be carefully reviewed during the course ofsystem design. The recommended practices in this document are intended to supplement,and not negate, any of the requirements in the NEC.1.2 DefinitionsFor the purposes of this document, the following terms and definitions apply. TheAuthoritative Diction
35、ary of IEEE Standards TermsB82and the NEC should bereferenced for terms not defined in this subclause.1.2.1 effectively grounded: Grounded through a sufficiently low impedance such that forall system conditions the ratio of zero-sequence reactance to positive-sequence reactance(X0/X1) is positive an
36、d not greater than 3, and the ratio of zero-sequence resistance topositive-sequence reactance (R0/X1) is positive and not greater than 1.1.2.2 equipment grounding conductor (EGC): The conductor used to connect the non-current-carrying metal parts of the equipment, raceways, and other enclosures to t
37、hesystem grounded conductor, the grounding electrode conductor (GEC), or both, at theservice equipment or at the source of a separately derived system.1.2.3 ground: A conducting connection, whether intentional or accidental, between anelectrical circuit or equipment and the earth, or to some other b
38、ody that serves in place ofthe earth. 1.2.4 grounded: Connected to earth or to an extended conducting body that serves insteadof the earth, whether the connection is intentional or accidental.1.2.5 grounded system: A system in which at least one conductor or point (usually themiddle wire or neutral
39、point of transformer or generator windings) is intentionallygrounded, either solidly or through an impedance. 2The numbers in brackets correspond to those of the bibliography in 1.17.IEEESYSTEM GROUNDING Std 142-2007Copyright 2007 IEEE. All rights reserved. 31.2.6 grounding system: A system that con
40、sists of all interconnected groundingconnections in a specific power system and is defined by its isolation from adjacentgrounding systems. The isolation is provided by transformer primary and secondarywindings that are coupled only by magnetic means. Thus, the system boundary is definedby the lack
41、of a physical connection that is either metallic or through a significantly highimpedance. 1.2.7 high-resistance grounded: A resistance-grounded system designed to limit ground-fault current to a value that can be allowed to flow for an extended period of time, whilestill meeting the criteria of R0
42、Xco,so that transient voltages from arcing ground faultsare reduced. The ground-fault current is usually limited to less than 10 A, resulting inlimited damage even during prolonged faults. 1.2.8 low-resistance grounded: A resistance-grounded system that permits a higherground-fault current to flow t
43、o obtain sufficient current for selective relay operation.Usually meets the criteria of R0/X0less than or equal to 2. Ground-fault current is typicallybetween 100 A and 1000 A. 1.2.9 per-phase charging current (Ico):The current (Vln/Xco) that passes through onephase of the system to charge the distr
44、ibuted capacitance per phase-to-ground of thesystem; Vlnis the line-to-neutral voltage and Xcois the per-phase distributed capacitivereactance of the system. 1.2.10 reactance grounded: Grounded through an impedance, the principal element ofwhich is inductive reactance. 1.2.11 resistance grounded: Gr
45、ounded through an impedance, the principal element ofwhich is resistance. 1.2.12 resonant grounded: A system in which the capacitive charging current isneutralized by an inductive current produced from a reactor connected between the systemneutral and ground. By properly “tuning” the reactor (select
46、ing the right tap), a lowmagnitude of fault current can be achieved. In general, when this occurs the arc will notmaintain itself and the ground fault is extinguished or “quenched.” In a parallel circuit,consisting of L and C, this happens when, 1.2.13 Rn: The value of the resistance connected from
47、the neutral to the ground of aresistance-grounded system. For high-resistance grounded systems where Rn is a majorcomponent of R0, the relationship R0 = 3Rn applies.1.2.14 R0: The per-phase zero-sequence resistance of the system. 1.2.15 separately derived system: A wiring system whose power is deriv
48、ed from agenerator, transformer, or converter windings and has no direct electrical connection,L1C- or f12 LC-=IEEEStd 142-2007 CHAPTER 14 Copyright 2007 IEEE. All rights reserved.including a solidly connected grounded circuit conductor, to supply conductorsoriginating in another system.1.2.16 solid
49、ly grounded: Connected directly through an adequate ground connection inwhich no impedance has been intentionally inserted. 1.2.17 static charge: The electricity generated when two dissimilar substances come intocontact. Conveyor belts are active producers of static electricity. 1.2.18 switching surge: A transient wave of overvoltage in an electric circuit caused bythe operation of a switching device interrupting current. 1.2.19 system charging current: The total distributed capacitive charging current (3Vln/Xco) of a three-phas
