1、 International Telecommunication Union ITU-T K.89TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (05/2012) SERIES K: PROTECTION AGAINST INTERFERENCE Protection of persons inside a structure using telecommunication services provided by metallic conductors against lightning Risk management Recommendat
2、ion ITU-T K.89 Rec. ITU-T K.89 (05/2012) i Recommendation ITU-T K.89 Protection of persons inside a structure using telecommunication services provided by metallic conductors against lightning Risk management Summary Recommendation ITU-T K.89 gives the methodology for evaluating the need to protect
3、users of telecommunication equipment in structures and that of building occupants related to the telecommunication installation. This method is based on a risk assessment: protection measures are necessary when the risk is greater than the tolerable risk. A maximum value of the tolerable risk is sug
4、gested. The risk is evaluated using the lightning risk components which can be a source of injury to telecommunication service users and building occupants (lightning flashes direct to the line or to the structures connected at the ends of the line). The risk assessment is done according to Edition
5、2 of IEC 62305-2. A simple risk assessment is provided to enable the telecommunication network operator to decide when to install gas discharge tubes (GDTs) at the point of entry of the telecommunication line into the structure independent of the structure attributes. This Recommendation can be used
6、 together with Recommendation ITU-T K.47, which provides a more accurate risk assessment of lightning flashes directly to the telecommunication line, and IEC 62305-2, which provides the risk assessment of lightning flashes to the structure. History Edition Recommendation Approval Study Group 1.0 ITU
7、-T K.89 2012-05-29 5 Keywords Lightning, node, protection, risk, risk assessment, surge, SPD, telecommunication line. ii Rec. ITU-T K.89 (05/2012) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and com
8、munication technologies (ICTs). 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 Recommendations on them with a view to standardizing telecommunications on a worldwide basis.
9、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 approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolutio
10、n 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 “Administration“ is used for conciseness to indicate both a telecommunication administration and
11、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 with the Recommendation is achieved when all of these mandatory provisions are met
12、. 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 required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibi
13、lity 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 Intellectual Property Rights, whether asserted by ITU members or others outside of the Rec
14、ommendation 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. However, implementers are cautioned that this may not represent the latest informati
15、on and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2012 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T K.89 (05/2012) iii Table of Contents P
16、age 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 4 5 Reference configuration 4 6 Explanation of terms . 5 6.1 Damage and loss . 5 6.2 Risk and risk components . 7 6.3 Composition of risk components r
17、elated to a structure 8 7 Risk management . 9 7.1 Basic procedure 9 7.2 Tolerable risk RT 9 7.3 Specific procedure to evaluate the need for protection 9 7.4 Protection measures 10 7.5 Selection of protection measures 10 8 Responsibility . 13 Annex A Assessment of annual number N of dangerous events
18、14 A.1 Assessment of the average annual number of dangerous events NLdue to flashes to a line . 14 Annex B Assessment of probability Pxof damage for a structure 15 B.1 Probability PA 15 B.2 Probability PB 15 B.3 Probability PC 15 B.4 Probability PM 15 B.5 Probability PU 15 B.6 Probability PV 16 B.7
19、Probability PW . 16 B.8 Probability PZ . 16 Annex C Assessment of amount of loss LXin a structure . 17 Appendix I Example of a risk assessment according to IEC 62305-2 . 18 I.1 General . 18 I.2 Building characteristics 18 I.3 Characteristics of the services 18 I.4 Characteristics of the internal sys
20、tems . 20 I.5 Zones definition in the structure . 21 iv Rec. ITU-T K.89 (05/2012) Page I.6 Expected dangerous events to the structure 22 I.7 Risk assessment for the unprotected structure 23 I.8 Selected protection measures . 23 I.9 Risk assessment related to the protected structure . 24 I.10 SPDs .
21、24 Appendix II Equipotential bonding. 26 II.1 Non-conductive floors 26 II.2 Lack of bonding between the telecommunication service, power service and the MEB . 26 Appendix III Cable routing . 27 Appendix IV Risk assessment using Recommendation ITU-T K.47 . 28 IV.1 Assessment of annual number N of dan
22、gerous events . 28 IV.2 Assessment of Factor PLDfor shielded cables 29 Appendix V Mechanisms of damage 30 V.1 Electric shock . 30 V.2 Fire or explosion . 35 Appendix VI Required current or voltage to cause injury 36 Bibliography. 42 Rec. ITU-T K.89 (05/2012) v Introduction Lightning flashes to earth
23、 may be hazardous to the telecommunication network, the structures at each end of the line and the telecommunication service users. The hazard can result in: injury of people inside the structures connected to the telecommunication line; physical damage (e.g., cable destruction) to the telecommunica
24、tion line or structures; failure (e.g., insulation breakdown) of the telecommunication line; failure of the associated electrical and electronic equipment inside the structure (i.e., exchange, customers building, or remote electronic site). To reduce the loss (due to electric shock, physical injury
25、or failure of internal systems) as a result of lightning flashes, protection measures may be required. Whether they are needed, and to what extent, will be determined by the risk assessment. The risk, defined in this Recommendation as the probable average annual loss due to injury as the result of l
26、ightning flashes, depends on: the annual number of lightning flashes influencing the structure; the probability of damage by one of the influencing lightning flashes; the mean amount of consequential loss. Lightning flashes influencing the structure may be divided into: flashes direct to a structure
27、 connected to the telecommunication line; flashes terminating on the telecommunication line entering the structure; flashes terminating near the telecommunication line; flashes terminating near the structure. Flashes direct to a telecommunication line or a structure connected to the telecommunicatio
28、n line may cause physical damage to the structure and the telecommunication line. More importantly, they may cause injury to telecommunication equipment users, cause a fire in the premises or damage equipment, which could immediately endanger life. Flashes near the telecommunication line or the stru
29、cture may also cause failure of the telecommunication line and of electrical and electronic systems inside the structures. The number of lightning flashes influencing the structure depends on the dimensions and the characteristics of the telecommunication network, the characteristics of the structur
30、e, on the environment characteristics, as well as on lightning ground flash density in the region where the structure is located. The probability of lightning damage depends on the telecommunication network, on the structure, on the lightning current characteristics, as well as on the type and effic
31、iency of applied protection measures. The annual mean amount of the consequential loss depends on the extent of damage and the consequential effects which may occur as result of a lightning flash. The use of protection will reduce the probability of damage and the amount of consequential loss. The a
32、ssessment of risk due to all possible effects of lightning flashes, to the telecommunication network and the structure, are given in this Recommendation. The decision to provide lightning protection may be taken regardless of the outcome of any risk assessment where there is a desire that there be n
33、o avoidable risk. vi Rec. ITU-T K.89 (05/2012) The boundary between IEC 62305-2 and ITU-T K.89 is that the former deals with the full risk assessment whereas the latter deals with the limitation of dangerous events at the structure from the telecommunication line. The telecommunication network opera
34、tor can contribute to the customers protection costs by limiting the number of dangerous events arriving at the customers structure from the telecommunication line. Rec. ITU-T K.89 (05/2012) 1 Recommendation ITU-T K.89 Protection of persons inside a structure using telecommunication services provide
35、d by metallic conductors against lightning Risk management 1 Scope This Recommendation deals with the risk management of lightning protection for occupants of a structure related to a telecommunication service using metallic conductor cables. Where the telecommunication service is provided by CDMA W
36、LL, or similar, refer to ITU-T K.71. The risk assessment is limited to injury of occupants where the installation of the telecommunication service increases the risk of injury due to lightning. This Recommendation provides a procedure for the evaluation of such a risk. Once an upper tolerable limit
37、for the risk has been selected, this procedure allows the selection of appropriate protection measures to be adopted to reduce the risk to a level at or below the tolerable limit. This Recommendation is mainly aimed at mitigating the risk associated with a telecommunication service in a private, pub
38、lic or commercial structure. The risks in telecommunication structures are generally mitigated by network operator practices and policies. However, this Recommendation can be used for telecommunication structures if agreed by the telecommunication operator. This Recommendation shall be used together
39、 with ITU-T K.72, which provides the risk assessment against lightning flashes to the telecommunication line. Recommendation ITU-T K.85 provides the risk assessment against equipment damage in customer premises. The protection need for line equipment (such as multiplexers, power amplifiers, optical
40、network units) and line termination equipment is not considered in this Recommendation and it should be evaluated using the risk assessment applied to the structure where the equipment is located (i.e., exchange, customers building, or remote electronic site). 2 References The following ITU-T Recomm
41、endations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are the
42、refore 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 Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a sta
43、nd-alone document, the status of a Recommendation. ITU-T K.21 Recommendation ITU-T K.21 (2011), Resistibility of telecommunication equipment installed in customer premises to overvoltages and overcurrents. ITU-T K.60 Recommendation ITU-T K.60 (2008), Emission levels and test methods for wireline tel
44、ecommunication networks to minimize electromagnetic disturbance of radio services. ITU-T K.66 Recommendation ITU-T K.66 (2011), Protection of customer premises from overvoltages. ITU-T K.71 Recommendation ITU-T K.71 (2011), Protection of customer antenna installations. ITU-T K.72 Recommendation ITU-
45、T K.72 (2011), Protection of telecommunication lines using metallic conductors against lightning Risk management. 2 Rec. ITU-T K.89 (05/2012) ITU-T K.85 Recommendation ITU-T K.85 (2011), Requirements for the mitigation of lightning effects on home networks installed in customer premises. IEC 62305-2
46、 IEC 62305-2 (2010), Protection against lightning Part 2: Risk management. IEC 62305-3 IEC 62305-3 (2010), Protection against lightning Part 3: Physical damage to structures and life hazard. IEC 62305-4 IEC 62305-4 (2010), Protection against lightning Part 4: Electrical and electronic systems within
47、 structures. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following term defined elsewhere: 3.1.1 telecommunication network ITU-T K.60: Entirety of equipment (comprising any combination of the following: network cable, telecommunication terminal equipment, and telecommunica
48、tion system or installation) that is indispensable to ensure normal intended operation of the telecommunication network. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 dangerous event: Lightning flash to or near the telecommunication line to be protec
49、ted which causes a dangerous surge voltage due to lightning. 3.2.2 dangerous surge voltage due to lightning: A surge voltage whose peak value Upis greater than the equipment resistibility or the conductor insulation surge voltage withstand level of the telecommunication line. 3.2.3 electronic system: System incorporating sensitive electronic components such as communication equipment, computers, control and instrumentation systems, radio systems and power electronic installations
