1、 IEEE Std 90003-2008 IEEE Std 90003-2008 IEEE Guide for the Protection of Communication Installations from Lightning Effects Sponsored by the Power Systems Communications Committee IEEE 3 Park Avenue New York, NY 10016-5997 USA 15 August 2011 IEEE Power Engineering Society IEEE Std 1692-2011IEEE Std
2、 1692TM-2011 IEEE Guide for the Protection of Communication Installations from Lightning Effects Sponsor Power Systems Communications Committee of the IEEE Power Engineering Society Approved 16 June 2011 IEEE-SA Standards Board Approved 19 November 2012 American National Standards Institute Abstract
3、: The document addresses methods and practices necessary to reduce the risk of damages to communications equipment within structures arising from lightning surges causing GPR (ground potential rise) and similar potential differences. Keywords: IEEE 1692, lightning, protection, communications equipme
4、nt, towers Acknowledgments: Figures 1, 2, and 7 reprinted with permission from Expert Systems Programs and Consulting, Inc., GPR-ExpertGround Potential Rise Protection using a High Voltage Interface. June 15, 1998. Original graphics of Figures 1, 2, and 7 copyrighted by John S. Duckworth, P.E., CEO,
5、 Expert Systems Programs and Consulting, Inc. The Institute of Electrical and Electronics Engineers, Inc. 3 Park Avenue, New York, NY 10016-5997, USA Copyright 2011 by the Institute of Electrical and Electronics Engineers, Inc. All rights reserved. Published 15 August 2011. Printed in the United Sta
6、tes of America. IEEE is a registered trademark in the U.S. Patent +1 978 750 8400. Permission to photocopy portions of any individual standard for educational classroom use can also be obtained through the Copyright Clearance Center. iv Copyright 2011 IEEE. All rights reserved. Introduction This int
7、roduction is not part of IEEE Std 1692-2011, IEEE Guide for the Protection of Communication Installations from Lightning Effects. The document addresses methods and practices necessary to reduce the risk of damages to communications equipment within structures arising from lightning surges causing G
8、PR (ground potential rise) and similar potential differences. According to the National Lightning Safety Institute accurate information about lightning-caused damage is elusive (see National Lightning Safety Institute B31).aThe U.S. Insurance Institute estimates the annual damages from lightning in
9、the United States to be $5 billion with the lightning strike claims, not including U.S. government property losses, paid per year being $820 million (see Brashear B6). Other sources provide much higher values. Lightning damage to equipment results in losses exceeding $26 billion annually in North Am
10、erica, and nearly three times that worldwide with more than 150 strikes per second (see Duckworth B9). Insurance payout resulting from lightning damage, accounts for approximately 7.5% of all U.S. insurance company distributions (see Brashear B6). Ironically, lightning damage to equipment could be a
11、ll but totally prevented. Special protection methods to minimize lightning damage are simple, very reliable, and inexpensive, particularly when compared to the cost of equipment repair and replacement, as well as the possible consequences of harm to personnel. However, methods for lightning special
12、protection cannot be found in the code books, e.g., National Electrical Code(NEC) or the National Electrical Safety Code(NESC).bPer the scopes of these two well-known codes, lightning protection is not covered, yet they are relied upon for practically all general construction in the United States. T
13、he Lightning Protection Standard(NFPA 780) should not be expected to provide guidance for the prevention of lightning damage to equipment. The scope of NFPA 780 covers the protection of structures only. NFPA 780 (4.18.3.2) does contain requirements for the surge protection of all service entrance si
14、gnal, data, and communication circuits as well as surge protection for all service entrance power circuits. Common grounding requirement (4.14) for electric service, communications, and antenna system grounds as well as underground metallic piping systems is also included in NFPA 780. Documented met
15、hods for the special protection of equipment from lightning cannot be found in the two main codes, NEC or NESC, or the Lightning Protection Standard that are systematically referred to for practically all general construction in the United States. This is in part the reason why there is so much need
16、less lightning damage. This guide is dedicated to providing special lightning protection methods for equipment and filling the vacuum that currently exists today (see Duckworth B9). Protection of the structure from lightning plays an important role in the protection of the equipment within the struc
17、ture. While the protection of the equipment is the main objective of this document, the protection of the structure housing the equipment is also covered in this document. The equipment housed in the structure is often worth many times the value of the structure. This standard was prepared by the Wi
18、re-Line Subcommittee of the IEEE Power Systems Communications Committee of the IEEE Power Engineering Society. aThe numbers in brackets correspond to those of the bibliography in Annex A. bNational Electrical Code, NEC, and NFPA 70 are registered trademarks in the U.S. Patent and connected to the gr
19、ounding system of towers or poles. 3.2 Acronyms and abbreviations ABD avalanche breakdown diode ac alternating current AWG American wire gauge BEP building entrance panel dc direct current EMP electro magnetic pulse GDT gas discharge tube GPR ground potential rise HVI high-voltage interface IEGR int
20、erior equipment ground ring LGPR lightning ground potential rise MCOV maximum continuous operating voltage MDF main distributing frame MGB master ground barMGN multigrounded neutral MOV metal oxide varistor MTBF mean time between failures NEC National Electrical Code NESC National Electrical Safety
21、Code NFPA National Fire Protection Association PSAP public safety answering point PVC polyvinyl chloride SAD silicon avalanche diode SAS silicon avalanche suppressor SBTC solid bare tinned copper SCR silicon controlled rectifier SPD surge protective device SPG single point ground TVSS transient volt
22、age surge suppression (see SPD) UPS uninterruptible power system 4. Overview and background This Guide presents recommended engineering design practices to reduce the risk of lightning damages to communications equipment within structures. If equipment is protected from damage by lightning, then per
23、sonnel using, or associated with, the equipment may also be protected. Specific measures for the protection of personnel are not covered in this Guide. 3 Copyright 2011 IEEE. All rights reserved. IEEE Std 1692TM-2011 IEEE Guide for the Protection of Communication Installations from Lightning Effects
24、 This Guide includes discussion on the following topics: Lightning effects on grounded towers, buildings, and equipment (Clause 5) Lightninga major source of ground potential rise (Clause 5) Divide and control lightning strike current (Clause 6) Tower location with respect to equipment building, ele
25、ctromagnetic radiation, need for Faraday cage (Clause 7) Grounding (earthing) considerations (Clause 8) Voltage divider circuit from lightning traveling down a tower (Clause 9) Single point ground location (Clause 9) Coordinate the coaxial cable entry with building equipment grounding (Clause 10) En
26、trance panel, bulkhead, or wave guide hatch (Clause 10) Isolate wire-line communications from remote earth (Clause 10) AC power surge protection and uninterruptible power system at the power entrance facility (Clause 11) AC disconnect isolation 5. Lightning effects Lightning is an electrical dischar
27、ge. The cloud-to-cloud or cloud-to-ground discharge generates electric, magnetic, and electromagnetic fields. The most significant field is the magnetic one. The magnetic field induces voltages in conductors and, if a loop is formed, currents in conductive loops. Cloud-to-ground or grounded structur
28、e discharges will cause a localized ground potential rise (GPR). Currents flowing in structures will cause localized differences in structure grounding voltage and the currents will create localized magnetic fields. Electrical equipment damage from lightning may be placed into three major categories
29、: Improper or insufficient grounding Lack of protection from GPR Lack of protection from lightning transients Improper or insufficient grounding will result in the equipment being stressed and/or damaged (potential difference) from nearby equipment, metal objects, misdirected current flow, etc. Lack
30、 of protection from GPR will result in the equipment being stressed from its connection to remote earth at some distant location through communication wire-lines or power supply wiring and/or from intrabuilding GPR arising from the voltage drop between power and telecommunication grounds references
31、(see IEEE Std C62.43 B23, and Ma and Dawalabi B29). Lightning GPR (LGPR) can result from strikes to objects or direct strikes to earth. Strikes to towers may have higher probability when towers or metallic structures are present, but sites without towers or metallic structures can suffer damage from
32、 nearby earth strikes. 4 Copyright 2011 IEEE. All rights reserved. IEEE Std 1692TM-2011 IEEE Guide for the Protection of Communication Installations from Lightning Effects High differential ground potentials between local equipment and remote power grounds make the power service conductors a favored
33、 discharge path for LGPR currents. Soil conditions have a significant effect on differential ground potentials. Higher soil resistivity will result in higher differential ground potentials from lightning strikes to earth. With cloud to ground electric potentials in the magnitude of tens of millions
34、of volts, an earth strike can be characterized as a current source. When the stroke discharge occurs the current traveling in the earth will flow regardless of the soil impedance. General application of ohms law will indicate the higher soil resistivity will result in a higher differential ground po
35、tential for a given discharge current. Sites without towers may experience LGPR effects as much, if not more, than sites with towers as they are less likely to have extensive grounding infrastructure. Sites at most risk are areas with a higher occurrence of lightning and high soil resistivity. 5.1 S
36、urge protective devices (SPD) and wire-line The standard surge protective devices (SPD) in the telecommunications industry, for the termination of communication wire-line services is the gas discharge tube (GDT). GDTs are also called gas tubes. GDTs can be found on virtually every telephone pair ter
37、minated in homes, buildings, and similar locations. GDTs are designed to shunt most current to ground. If the magnitude shunted does not exceed a certain threshold the SPD will help protect equipment, and personnel, from harm. Most shunting devices, however, do not fully protect network electronic e
38、quipment from a GPR or “outgoing current,” whether induced from lightning or from a faulted power line. When shunting devices are connected to an elevated ground (outgoing current) during a GPR event, they merely offer an additional current path off the site to remote earth (the other end). When SPD
39、s (GDTs, MOVs, ABDs, SCRs, SADs, SASs, etc.) are used as ground shunting devices, they will not protect equipment from GPR. These devices merely offer an additional path to remote earth through the communication pairs for any and all outgoing currents. When there is a GPR event the SPD provides a co
40、nnection of the communication path in the reverse direction from which they were intended to operate and increases the possibility of equipment damage to telephone and power installations. The most susceptible locations are those where the equipment is located near, or under, towers and/or are locat
41、ed at a higher altitude than the surrounding area. Some of the susceptible locations to equipment damages include the Public Safety Answering Point locations (also called 911 PSAP). The typical 911 PSAP center is a relatively small building under, or near, a radio tower. This tower is a likely targe
42、t for lightning. Personnel taking emergency calls coming into the PSAP may be at a higher risk since they must be at the phones at all times and cannot be off the phones during lightning storms, as recommended in virtually every telephone book in the United States. For additional information see ATI
43、S 0600321 B2. Whether the site is a 911 PSAP center or a cellular telephone (radio) antenna on top of a mountain, special protection methods are available and must be used to reduce the risk of lightning damage to equipment and associated working personnel. Methods will be presented in this Guide to
44、 enable engineers to incorporate them into the general construction design. Effective protection of sensitive equipment with SPD shunting devices is complex. A well-designed installation requires coordination of the protection for low-voltage power feeds (ac and dc) with the protection for telecommu
45、nications facilities in order to minimize the effect of intrabuilding GPR. The use of secondary SPD is recommended to supplement the primary SPD (see ITU-T K.11 B26). Surge resistibility and impedance of the terminal equipment must be compatible with the selected primary SPD. 5 Copyright 2011 IEEE.
46、All rights reserved. IEEE Std 1692TM-2011 IEEE Guide for the Protection of Communication Installations from Lightning Effects Finally, secondary and primary SPD must be coordinated to optimize adequate operation (see IEEE Std C62.43 B23, ATIS 0600338 B4, ITU-T K.36 B27, and ITU-T K.11 B26). Even wit
47、h a well-designed installation, part of the lightning current will reach the equipment and, in some cases, can affect service quality and/or cause equipment damage. 5.2 Isolation techniques To minimize the risk of equipment damage due to energy exchange between grounds, special protection devices ba
48、sed on isolation techniques are very effective. The isolation protection techniques are particularly recommended for: 1) The protection of non-interruptible (class A) service (see IEEE Std 487-2007 or IEEE Std 1590-2009) 2) The protection of sensitive equipment not designed for operation with standa
49、rd primary SPD 3) Sites exhibiting excessive trouble reports due to lightning activity 5.2.1 Wire-line isolation Figure 1 and Figure 2 show the value of isolation in communication circuits.6NOTE7Reprinted with permission from Duckworth et al. B10 Figure 1 Communications without isolation protection 6For simplification, power feeding of the isolation device is not shown. Grounding arrangement of a telecommunication room is much more complex. Grounding standards for telecommunication rooms must be strictly follo
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