ANSI ATIS 0600334-2013 Electrical Protection of Communications Towers and Associated Structures.pdf

1、 AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS ATIS-0600334.2013 ELECTRICAL PROTECTION OF COMMUNICATIONS TOWERS AND ASSOCIATED STRUCTURES As a leading technology and solutions development organization, ATIS brings together the top global ICT companies to advance the industrys most-pressing busin

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4、artner for the 3rd Generation Partnership Project (3GPP), a founding Partner of oneM2M, a member and major U.S. contributor to the International Telecommunication Union (ITU) Radio and Telecommunications sectors, and a member of the Inter-American Telecommunication Commission (CITEL). For more infor

5、mation, visit . AMERICAN NATIONAL STANDARD Approval of an American National Standard requires review by ANSI that the requirements for due process, consensus, and other criteria for approval have been met by the standards developer. Consensus is established when, in the judgment of the ANSI Board of

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8、standards. The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover, no person shall have the right or authority to issue an interpretation of an American National Standard in the name of the

9、American National Standards Institute. Requests for interpretations should be addressed to the secretariat or sponsor whose name appears on the title page of this standard. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American Nationa

10、l Standards Institute require that action be taken periodically to reaffirm, revise, or withdraw this standard. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute. Notice of Disclaimer equalize po

11、tential differences between equipment; and minimize the introduction of electrical noise. All radio/communication towers shall meet TIA/EIA 222-G structural construction requirements. 1.1 Application of Electrical Protection Not every communications tower or associated building will require the same

12、 level of electrical protection. The electrical protection measures and surge protective device applications presented shall be used where electrical protection is required. Other factors, such as those related to telecommunications service reliability or local codes and standards, may dictate the n

13、eed for electrical protection measures that exceed those described in this standard. 2 Normative References The following standards contain provisions which, through reference in this text, constitute provisions of this American National Standard. At the time of publication, the editions indicated w

14、ere valid. All standards are subject to revision, and parties to agreements based on this American National Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. The following documents or portions thereof are referenced within

15、this standard and shall be considered part of the requirements of this document. ANSI/NFPA 70-2011, National electrical code.1ANSI/NFPA 780-2011, Standard for the installation of lightning protection systems.1 ATIS-0600316.2013, Electrical Protection of Telecommunications Outside Plant.21This docume

16、nt is available from the National Fire Protection Association (NFPA). ATIS-0600334.2013 2 TIA/EIA-222-G, Structural standards for steel antenna towers and antenna supporting structures.3ANSI/IEEE 487- 2007, IEEE guide for the protection of wire-line communication facilities serving electric power st

17、ations.4ANSI/IEEE 1590-2009, Recommended Practice for the Electrical Protection of Communication Facilities Serving Electric Supply Locations Using Optical Fiber Systems.4IEEE Standards Dictionary Online.53 Definitions Unless otherwise defined in this clause, the definitions of all terms used in thi

18、s standard conform to the IEEE Standards Dictionary Online. 3.1 counterpoise: A conductor or system of conductors arranged beneath the line; located on, above, or most frequently below the surface of the earth; and connected to the grounding system of the towers or poles supporting the line. 3.2 iso

19、keraunic level: The average annual number of thunderstorm days. 3.3 messenger: A strand, typically of galvanized steel wires, that carries or supports an aerial cable The messenger is normally part of the cable construction and typically used for drop-cables. 3.4 strand: A bundle of wires that are t

20、wisted together to form a flexible cable capable of withstanding large tensile stress. The most common strands are composed of galvanized steel wires. Outside plant cables are normally lashed around the strand for support. Outside of the document, “strand” and “messengers” have been used interchange

21、ably. 3.5 structure: A building, hut, or cabinet that houses or contains radio, microwave, or similar equipment. 3.6 surge absorbers: Materials or components that dissipate surges into the earth e.g., grounding electrode systems, ground rods, ground rings, building steel, etc. 3.7 surge producer: So

22、urces of surges e.g., outside plant cable shields, AC or DC power conductors, towers, other metallic components. 4 Abbreviations, Acronyms, personnel facilities (including metal partitions, desks, and filing cabinets); electrical apparatus cabinets such as AC service distribution, control, or lighti

23、ng; and metal battery stands. Metallic conduits, pipes, raceways, and ducts, when joined by conventional means (i.e., without slip joints) that terminate in bonded metallic cabinets may be considered adequately bonded, and do not require a separate bond to the interior ground ring. Points of discont

24、inuity in conduits, pipes, raceways, and ducts may be made electrically continuous by bonding across the point of discontinuity with a 6 AWG wire. 7.8 Lightning Arresters for Coaxial Cable specifically, between each phase and neutral, typically where this neutral is grounded. All indoor SPDs shall h

25、ave a self-disconnecting failure mode. This protection failure mode shall result in an alarm indication. Secondary SPDs are available for various service ratings starting at 120 Vac. These shall be rated for the application. ATIS-0600334.2013 15 10.4 Bonding to Power Bond all conduits, armored cable

26、s, and switch boxes containing power wires to provide direct, low-resistance paths to ground for surge currents. 10.5 Branch Circuit SPDs Branch circuit SPDs are used to protect the branch power circuit to the tower for the aircraft warning lights (at the tower). All branch power circuits entering o

27、r exiting any building shall have surge protection. All SPD for circuits exiting the building shall be bonded to the building ground system In areas of high lightning incidence, attach a metal lightning rod, extending a minimum of 12 inches 305 mm above the highest fixture, to the antenna support an

28、d bond the rod to the grounding conductor or the metallic antenna support (mast or pole). Use the ground system at the base of the pole or tower as the lightning rod ground. Bond across expansion joints in the metallic conduit containing the ac wiring to the warning lights to ensure continuity. Bond

29、 the metallic conduit to the metallic tower every 10 feet 3 m through the mounting hardware. In addition to the power SPDs at the main service, provide branch-circuit secondary SPDs on circuits feeding power to susceptible equipment such as rectifiers, power supplies, cable air pressure machines, we

30、ll pumps, and other susceptible equipment. Mount the secondary branch circuit SPD as close as practicable to the equipment that it is protecting. 11 OSP Entrance Facilities The telephone entrance facilities to radio stations are subject to foreign potentials and currents from both induction and cond

31、uction processes. 11.1 Telephone Facilities For radio stations in urban areas, the antenna arrangements and path for diverting lightning strikes to ground (earth) reduces the possibility of damaging currents affecting telephone facilities. However, telephone facilities entering the site must be prot

32、ected. At radio stations in rural areas, telephone facilities need additional protection because the incidence of lightning strikes to the antenna is usually higher than in urban areas. Telephone cable serving stations in rural areas typically have small diameter sheaths. Therefore, these cables are

33、 more susceptible to damage from lightning currents, have relatively high longitudinal resistance, and can develop high sheath-to-pair voltages with low lightning currents on the sheath. Such voltages can damage the cable to the extent that the cable might need to be replaced. 11.2 Cable Shields The

34、 demarcation point between the wireline service provider and wireless service provider is often an H-frame type of structure. Cabling is placed from this demarcation point to the wireless service provider structures or enclosures. The wireless service provider telephone cabling used between the wire

35、line service providers demarcation point and the wireless service provider equipment shall be shielded and shall be grounded on both ends. Alternatively, a metallic conduit could be used instead of the shielded cable as long as the metallic conduit is bonded to ground at both ends. A third alternati

36、ve is to run a ATIS-0600334.2013 16 copper conductor inside a non-metallic conduit as long as this copper conductor is bonded to ground at both ends. The telecommunication cable between the wireline service provider and the wireless service provider shall have a listed primary protector installed on

37、 both ends. The wireline service provider normally provides a protector on the demarcation point end of this cable. The wireless service provider normally places protectors on the other end. When lightning strikes a cell site tower, massive currents are diverted to earth in the vicinity of the tower

38、, which momentarily raises the electrical potential of the ground in the vicinity of the cell site. Surge currents will flow through all the available paths (in inverse proportion to the resistance of each path) until the ground potentials are equalized. If the wireless service providers cable betwe

39、en the cell site and wireline service providers demarcation point is unshielded, lightning caused voltage transients will force surge currents to flow through the tip and ring conductors, then through a protector at the Network Interface Unit (NIU), potentially damaging the cell site equipment, and/

40、or the protectors, and/or the NIU. However, if a shielded cable or one of the alternative shielding methods is used, the transient currents will also flow through this shielding path, reducing the amount of transient current flowing on the tip and ring conductors. This shielding path must be bonded

41、to earth at both ends to allow these transient currents to flow. 11.3 Telephone Service Protection Radio station sites having telephone service provided should have the protector, NID (Network Interface Device), and BET (Building Entrance Terminal) properly grounded with direct and straight connecti

42、ons to the sites grounding system. If the BET is inside the building or hut, connect the ground terminal to the Master Ground Bar via a direct and shortest possible route. Protected terminals used with facilities serving radio sites should have protectors either gas tubes (GDT) or solid-state module

43、s. There is an increasing need for additional bandwidth for wireless services. This is resulting in the deployment of higher speed telecommunications equipment capable of delivering DS3 or 1000BaseT type Ethernet services. This type of equipment may not be designed for the hostile electrical protect

44、ion environment associated with a tower, particularly in a high lightning area. Consideration should be given to the design of the telecommunications and DC power ports of such equipment to insure that they will be able to withstand the electrical surges associated with lightning at a tower. These p

45、orts may need to be designed to more stringent requirements than those found in Telcordia GR 1089-CORE for Type 3, Type 5, and Type 8 ports. In addition, these ports should be designed to have voltage isolation or protector coordination to protect them from GPR damage. 11.4 Entrance Cables Where com

46、munication circuits enter radio sites by cable, at least 6 feet 1.8 m of the entrance cable shall be 24 AWG wire and shall terminate inside the building in an interior terminal box (BET or NID) equipped with protectors. All pairs entering the radio building or hut shall be terminated on protectors (

47、either gas tubes or solid-state modules). 11.4.1 Aerial Cable Entrance Aerial entrance facilities shall have the cable shield and the strand bonded and grounded at the last pole before the entry point and bonded to the MGN (Multi Grounded Neutral), if present. When the support strand or messenger is

48、 attached at the building, the strand or messenger shall be bonded to the ground ring. All pairs (working and non-working) entering the building shall terminate on protectors (either gas tubes or solid-state modules). ATIS-0600334.2013 17 11.4.2 Buried Cable Entrance Buried entrance facilities shall

49、 have the cable shield bonded and grounded at the last pedestal before the entry point and bonded to the MGN, if present. All pairs (working and non-working) entering the building shall terminate on protectors (either gas tubes or solid-state modules). 11.5 Other Circuits Other types of cables (such as video pairs and coaxial cables) that provide circuits to the radio site shall also be protected. The metallic members of these cables shall be bonded at the first point of access as they enter the building and bonded together to the sites grounding (earthi