1、 International Telecommunication Union ITU-T K.71TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2007) SERIES K: PROTECTION AGAINST INTERFERENCE Protection of customer antenna installations ITU-T Recommendation K.71 ITU-T Rec. K.71 (07/2007) i ITU-T Recommendation K.71 Protection of customer ant
2、enna installations Summary ITU-T Recommendation K.71 provides information to network operators on when antennas may be installed in, or on, a customer building without performing a building-specific risk assessment. When a risk assessment is required, it provides guidance on the application of IEC 6
3、2305-2. It also provides information on the responsibilities of the network operator and the building owner. Source ITU-T Recommendation K.71 was approved on 29 July 2007 by ITU-T Study Group 5 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. K.71 (07/2007) FOREWORD The Intern
4、ational Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendat
5、ions on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approv
6、al of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administratio
7、n“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance w
8、ith the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is requi
9、red of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellect
10、ual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. How
11、ever, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2008 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the p
12、rior written permission of ITU. ITU-T Rec. K.71 (07/2007) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation. 2 4 Abbreviations and acronyms 2 5 Reference configuration 3 6 Protection need against lightning . 5 7 Site cl
13、assification 6 7.1 Antenna installed within, or attached to, the building 6 7.2 Antenna installed near the building 8 8 Methods of protection. 8 8.1 General . 8 8.2 Contact with the mains . 9 8.3 Direct lightning strike protection 9 9 Protection requirements 9 9.1 General . 9 9.2 Antenna installed w
14、ithin, or attached to, the building 10 9.3 Antenna installed near to the building 12 9.4 Earthing and bonding . 14 9.5 Selection and dimensioning of the surge protection devices (SPDs) . 15 10 Responsibilities. 17 Annex A Direct lightning to the structure: equipotential bonding of a shielded cable a
15、t the entrance of the structure 19 Appendix I Antenna on buildings used as air termination of the LPS 20 Appendix II Generic risk assessment 21 II.1 Site with a roof antenna deemed to be low risk 21 II.2 Risk calculations. 23 Appendix III Example: Antenna installed near a building . 29 III.1 General
16、 . 29 III.2 Building characteristics 29 III.3 Characteristics of the services 29 III.4 Characteristics of the internal systems . 31 III.5 Zones definition in the structure. 32 iv ITU-T Rec. K.71 (07/2007) Page III.6 Expected dangerous events to the structure 33 III.7 Risk assessment for the unprotec
17、ted structure 33 III.8 Selected protection measures . 35 III.9 Risk assessment related to the protected structure . 36 III.10 SPDs . 38 ITU-T Rec. K.71 (07/2007) 1 ITU-T Recommendation K.71 Protection of customer antenna installations 1 Scope Telephony services delivered via an antenna installation
18、may be subjected to lightning discharges. This Recommendation provides requirements to minimize the risk of injury to users of the service and damage to equipment. It provides requirements to achieve protection of telecommunications and video content antenna systems, including satellite antennas, ag
19、ainst lightning discharges and mains contact including contact with aerial power service leads. When protection against direct lightning discharges is not required, this Recommendation requires protection against mains contact to minimize the risk of injury to users of the service and to network ope
20、rator personnel. When protection against direct lightning discharges is required, this Recommendation defines protection measures distinguishing two cases: 1) The antenna is located on the building. 2) The antenna is installed on a mast near to the building at a maximum distance of about ten metres.
21、 This Recommendation does not provide methods to protect the antenna and associated cabling against a direct strike to the antenna mast (see clause 7.2). Damage to equipment is minimized by providing requirements to achieve protection against lightning. This Recommendation provides requirements for:
22、 the resistibility of the equipment; how and when to protect the customers premises from direct strikes; how and when to bond the mast or tower to the customer building electrical installation earthing system; how and when to protect the services, i.e., the power supply for the service, the telecomm
23、unication line and the antenna cable, entering the customers building. This Recommendation does not apply to structures where there is the risk of explosion, nor to hospitals with life-saving electrical equipment or structures where failures of internal systems immediately endanger human life. This
24、Recommendation covers the protection of antennas installed at private buildings ranging in size from small single-storey buildings up to multi-storey buildings. This Recommendation only applies in the case when the antenna is being installed to supply service to the building on which the antenna is
25、being installed. For radio base station installations refer to ITU-T K.56. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated
26、were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recomme
27、ndations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. 2 ITU-T Rec. K.71 (07/2007) ITU-T K.21 ITU-T Recommendation K.21 (2003), Resistibility of telecommunication equipment installed in cust
28、omer premises to overvoltages and overcurrents. ITU-T K.47 ITU-T Recommendation K.47 (2000), Protection of telecommunication lines using metallic conductors against direct lightning discharges. ITU-T K.56 ITU-T Recommendation K.56 (2003), Protection of radio base stations against lightning discharge
29、s. ITU-T K.66 ITU-T Recommendation K.66 (2004), Protection of customer premises from overvoltages. IEC 60364-5-54 IEC 60364-5-54 (2002), Electrical installations of buildings Part 5-54: Selection and erection of electrical equipment Earthing arrangements, protective conductors and protective bonding
30、 conductors. IEC 60728-11 IEC 60728-11 (2005), Cable networks for television signals, sound signals and interactive services Part 11: Safety. IEC 60950-1 IEC 60950-1 (2005), Information technology equipment Safety Part 1: General requirements. IEC 62305-1 IEC 62305-1 (2006), Protection against light
31、ning Part 1: General principles. IEC 62305-2 IEC 62305-2 (2006), Protection against lightning Part 2: Risk management. IEC 62305-3 IEC 62305-3 (2006), Protection against lightning Part 3: Physical damage to structures and life hazard. IEC 62305-4 IEC 62305-4 (2006), Protection against lightning Part
32、 4: Electrical and electronic systems within structures. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following term defined elsewhere: 3.1.1 exposed structure: (See ITU-T Rec. K.25) A structure, e.g., telecommunications tower, high building, which needs to be protected aga
33、inst direct lightning strokes. 3.2 Terms defined in this Recommendation This Recommendation defines the following term: 3.2.1 antenna system: The antenna connecting cable and terminating equipment. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: BB Bon
34、ding Bar CDMA WLL Code Division Multiple Access Wireless Local Loop GDT Gas Discharge Tube LPL Lightning Protection Level LPS Lightning Protection System MEB Main Earth Bar PoE Point of Entry ITU-T Rec. K.71 (07/2007) 3 R Risk value R1Risk of loss of human life R2Risk of loss of service RA1Risk of l
35、oss of human life related to injury of living beings caused by touch and step voltages due to flashes to the structure RBRisk component related to physical damage caused by dangerous sparking inside the building due to flashes to the structure RB1Risk of loss of human life related to physical damage
36、 caused by dangerous sparking inside the building due to flashes to the structure RcRisk component related to physical damage due to flashes to the building RMRisk component related to physical damage due to flashes near the building RTTolerable risk value RT1Tolerable risk of loss of human life RT2
37、Tolerable risk of loss of service RURisk component related to injury to living beings caused by touch voltage inside the structure due to flashes to the service RvRisk component related to physical damage caused by dangerous sparking inside the building due to flashes to the service RwRisk component
38、 related to physical damage due to flashes to the service RzRisk component related to physical damage due to flashes near the service SPD Surge Protection Device 5 Reference configuration Telephony services delivered via an antenna installation have the following two reference configurations: 1) the
39、 antenna is located on the building (Figure 1a); 2) the antenna is installed on a mast near to the building (Figure 1b). In both configurations, the antenna is connected to the associated equipment with shielded symmetrical pair cable or with a coaxial cable. The associated equipment, powered by mai
40、ns, is connected to the end user equipment, e.g., a personal computer (PC) (for example via a serial or USB cable), and to the external telecommunication line. Further examples of the reference configurations covered by this Recommendation are shown in Figures 1c to 1e. 4 ITU-T Rec. K.71 (07/2007) K
41、.71(07)_F1a K.71(07)_F1bMainsMainsAssociatedequipmentSerial cableAntennaEnd userequipment, e.g., PC,MainsMainsAssociatedequipmentSerial cableAntennaEnd userequipment, e.g., PC,TelecomportTelecomportFigure 1a Antenna attached to structure Figure 1b Antenna installed on a mast K.71(07)_F1cPower boardM
42、ain earthingterminal Telecoms servicee.g., CDMA WLLPOTSPowered telecommunicationsequipment e.g., a PCpower lineFigure 1c Basic antenna-provided service Figure 1d Basic antenna-provided service with service extended to an out-building ITU-T Rec. K.71 (07/2007) 5 K.71(07)_F1ePower boardMain earthingte
43、rminalAntenna fordata (satelliteor wireless)POTSPowered telecommunicationequipment e.g., PCpower lineDatamodemNetwork access nodeSwitch, etc.MaindistributionframeFigure 1e Telecommunications service plus an antenna for Internet service 6 Protection need against lightning The need for lightning prote
44、ction is determined by performing a risk assessment according to IEC 62305-2, which compares the risk value R, as the sum of all the risk components, with the tolerable risk value RT. To minimize the risk of injury to users, the risk of loss of human life (R1) related to the building shall be evalua
45、ted by the building owner and compared with the tolerable risk value (RT1). A maximum value of the tolerable risk of loss of human life equal to 105is assumed by this Recommendation. When the risk R1of the building, with the antenna installation, is less than the tolerable risk RT1, the site is cons
46、idered inherently protected against direct lightning. In this case, the antenna need only be protected against mains contact (clause 8.2). When R1 RT1lightning protection, against the loss of human life in the building, is required. This Recommendation defines the methods of protection (clause 8) an
47、d the protection requirements (clause 9). To minimize the risk of damage to equipment inside the building, the risk of loss of service (R2) should be evaluated and compared with the tolerable risk of loss of service value RT2= 103or a lower value according to the customers decision. Even when R1RT2,
48、 protection is recommended and the knowledge of the risk component values guides the protection designer in selecting the most adequate protective measures in order to protect the equipment inside the building. This evaluation and the relevant protective measures are outside the scope of this Recomm
49、endation. The risk assessment of loss of service R2related to the antenna system when the antenna is installed near the building is not necessary because this risk is very low due to both the short length (in general less than 50 m) of the cabling and the presence of the shield (coaxial pair or shielded line). The protection needs of the antenna cable against physical damage due to a direct lightning to the building is considered in the risk assessment against the loss of human life (see clause 9.5 and Appen
