1、 International Telecommunication Union ITU-T K.69TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (10/2006) SERIES K: PROTECTION AGAINST INTERFERENCE Maintenance of protective measures ITU-T Recommendation K.69 ITU-T Rec. K.69 (10/2006) i ITU-T Recommendation K.69 Maintenance of protective measures S
2、ummary This Recommendation gives guidance on the maintenance of protective measures (protective devices and assemblies and their earthing) in telecommunication installations. It deals with the maintenance of the protection of telecommunication equipment, installations and cable plants exposed to the
3、 results of external sources of interference such as overvoltages and overcurrents due to lightning discharges or power induction. The maintenance activity is achieved with visual and complete inspections during periodical controls defined by this Recommendation. The complete inspection includes the
4、 visual inspection and additional measurements or investigations. The purpose of the maintenance activity is to control the effectiveness of the protective measures against overvoltages and overcurrents to avoid or reduce hazard to people, damage to installations and disturbances to systems taking i
5、nto account the corrosion effects. The effectiveness of the protective measures against corrosion is also considered. Source ITU-T Recommendation K.69 was approved on 29 October 2006 by ITU-T Study Group 5 (2005-2008) under the ITU-T Recommendation A.8 procedure. Keywords Examining period, inspectio
6、n, maintenance, protective measures. ii ITU-T Rec. K.69 (10/2006) FOREWORD The International 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 respo
7、nsible for studying technical, operating and tariff questions and issuing Recommendations 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 I
8、TU-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 Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborati
9、ve basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ 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 man
10、datory provisions (to ensure e.g. interoperability or applicability) and compliance with 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. Th
11、e 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 possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU take
12、s no position concerning the evidence, validity or applicability of claimed Intellectual 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 proper
13、ty, protected by patents, which may be required to implement this Recommendation. However, 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 2007 All rights reserved.
14、No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. K.69 (10/2006) 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 acr
15、onyms 3 5 Maintenance of protective measures 3 5.1 General . 3 5.2 Maintenance of earthing systems . 4 5.3 Maintenance of lightning protection measures for structures 5 5.4 Maintenance of lightning protective measures for telecommunication systems . 6 5.5 Maintenance of power induction protection me
16、asures. 7 5.6 Maintenance of power line crossover protection measures 8 5.7 Maintenance of corrosion protection measures 9 5.8 Maintenance of protection measures on power systems (mains) . 10 6 Documentation 11 Appendix I Network operator experiences on maintenance of GDT 13 I.1 France Telecom (FT)
17、13 I.2 Deutsche Telekom (DT) . 13 Appendix II SPD-testing equipment. 14 Appendix III Examples of documentation and local labelling . 15 III.1 Example of the marking of influencing systems in topographical maps 15 III.2 Example of local labelling of influenced systems 15 III.3 Example of local labell
18、ing of corrosion protection systems 15 III.4 Examples of labelling ESD protected areas or equipment . 16 Bibliography. 17 ITU-T Rec. K.69 (10/2006) 1 ITU-T Recommendation K.69 Maintenance of protective measures 1 Scope Telecommunication networks can be endangered by atmospheric discharge, power indu
19、ction, power line crossover and corrosion. The application of protective measures becomes necessary to: reduce the risk of injury for the user and the personnel; optimize the reliability of the network controlling: the risk of damages of the telecommunications network; the loss of function or the re
20、duced performances of the telecommunications service. This Recommendation gives an overview of the maintenance of these protective measures. Maintenance of the protection measures and precautions against electrostatic phenomena are not subject of this Recommendation because they are set in general.
21、Appendix III gives an overview how electrostatic protected areas or telecommunications systems have to be labelled. 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 tim
22、e of publication, the editions indicated 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
23、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 stand-alone document, the status of a Recommendation. ITU-T K.5 ITU-T Recommendation K.5 (1988), Joint use of poles for electricity distribution and
24、 for telecommunications. ITU-T K.6 ITU-T Recommendation K.6 (1988), Precautions at crossings. ITU-T K.12 ITU-T Recommendation K.12 (2006), Characteristics of gas discharge tubes for the protection of telecommunications installations. ITU-T K.27 ITU-T Recommendation K.27 (1996), Bonding configuration
25、s and earthing inside a telecommunication building. ITU-T K.31 ITU-T Recommendation K.31 (1993), Bonding configurations and earthing of telecommunication installations inside a subscribers building. ITU-T K.33 ITU-T Recommendation K.33 (1996), Limits for people safety related to coupling into teleco
26、mmunications systems from a.c. electric power and a.c. electrified railway installations in fault conditions. ITU-T K.35 ITU-T Recommendation K.35 (1996), Bonding configurations and earthing at remote electronic sites. ITU-T K.50 ITU-T Recommendation K.50 (2000), Safe limits of operating voltages an
27、d currents for telecommunication systems powered over the network. ITU-T K.53 ITU-T Recommendation K.53 (2000), Values of induced voltages on telecommunication installations to establish telecom and a.c. power and railway operators responsibilities. 2 ITU-T Rec. K.69 (10/2006) ITU-T K.66 ITU-T Recom
28、mendation K.66 (2004), Protection of customer premises from overvoltages. ITU-T K.68 ITU-T Recommendation K.68 (2006), Management of electromagnetic interference on telecommunication systems due to power systems. ITU-T Earthing ITU-T Handbook (2003), Earthing and Bonding. ITU-T Directives VII ITU-T
29、Directives, volume VII (1989), Protective measures and safety precautions. IEC 62305-1 IEC 62305-1 (2006), Protection against lightning Part 1: General principles. IEC 62305-3 IEC 62305-3 (2006), Protection against lightning Part 3: Physical damage to structures and life hazard. IEC 62305-4 IEC 6230
30、5-4 (2006), Protection against lightning Part 4: Electrical and electronic systems within structures. 3 Definitions 3.1 Terms defined elsewhere None. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 maintenance: Combination of all technical and administ
31、rative actions, including supervision actions, intended to retain an item in, or restore it to, a state in which it can perform a required function. 3.2.2 visual inspection: Action comprising careful scrutiny of an item carried out either without dismantling, or with the addition of partial dismantl
32、ing as required. 3.2.3 complete inspection: Visual inspection, supplemented by means such as measurement, in order to arrive at a reliable conclusion as to the condition of an item. 3.2.4 repair: That part of a corrective maintenance in which manual actions are performed on the item to re-establish
33、a required function. 3.2.5 examining period: Time period in years between the implementation of a protective measure and its first inspection or time period between two inspections. 3.2.6 active reduction system (ARS): An active reduction system uses a transformer to compensate for induced voltages
34、in the telecommunication cable system. It operates on the basis that, via a transformer, a voltage with a phase shift by 180 but of the same amplitude, is coupled into the telecommunication cable to be protected. It consists of a coupling element (iron core with a primary winding, a control winding
35、connected to a pilot conductor, a corresponding number of secondary windings) and an amplifier with a power supply. 3.2.7 passive reduction system (PRS): A passive reduction system uses a step-down transformer to compensate for induced voltages in the telecommunication cable system. It consists of a
36、n iron core with a primary winding (the grounded cable sheath or a pilot conductor) and a corresponding number of secondary windings. In general, the secondary windings are shielded telecommunication cables. 3.2.8 pilot conductor: Grounded wire, grounded on both sides of the influenced path to gener
37、ate the steering voltage for the control winding of the ARS or PRS. ITU-T Rec. K.69 (10/2006) 3 4 Abbreviations and acronyms This Recommendations uses the following abbreviations and acronyms: ARS Active Reduction System EBB Equipotential Bonding Bar EBP Earth Bonding Point EPA Electrostatic Protect
38、ed Area ESD Electrostatic Discharge GDT Gas Discharge Tube LPS Lightning Protection System MDF Main Distribution Frame MET Main Earthing Terminal NT Network Termination PRS Passive Reduction System RCD Residual Current Device SPD Surge Protective Device 5 Maintenance of protective measures 5.1 Gener
39、al 5.1.1 General requirements Protective measures of the telecommunication and signalling networks and/or of telecommunication structures (e.g., exchange building and remote sites) are the result of the protection need evaluation before construction or in the event of changes of plant, and they are
40、integral part of a protected system. All protective measures have to be documented to prove that they correspond to the obligation to exercise due care. Protective measures have to be inspected to ensure that they can perform a required function. All measuring results have to be documented and, toge
41、ther with the inspection protocols, are to be kept for as long as the protective measure exists. They have to be compared with the results of previous inspections (see Note 2). This proves if the results differ fundamentally from earlier values, then the reasons for the deviation need to be determin
42、ed and solved. NOTE 1 The network operator might decide to have local identification at the plant, such as the marking of equipment and protective devices. An example of the marking of influencing systems in topographical maps and the local marking of influenced systems is given in Appendix III. Sub
43、sequent protective measures or the inspection of the existing ones might become necessary in the following cases: repeated appearance of damage caused by electrical sources; later erection of exposed structures; later erection or changes to electric power plants/traction systems; change of the opera
44、ting currents in existing power plants/traction systems; upon customer or authority request. 4 ITU-T Rec. K.69 (10/2006) The maintenance of the interconnection of cable screens and the earthing of the screen at both ends including equipotentialization of the system is seen as the most effective prot
45、ective measure of a telecommunication system and is assumed for all protective measures described below. NOTE 2 It has to be taken into account that measuring results may be influenced by the ambient conditions. 5.1.2 Maintenance responsibilities The operator of the telecommunication network is resp
46、onsible for the protection of his plant within the network. The building owner is responsible for the overall safety of the installation within the building, providing a bonding terminal, EBB or access to the MET, to enable the earthing of the protective measures. The customer is responsible for the
47、 protection of his (private) network in his property. All parties are responsible for the effectiveness and documentation of the protective measures in their premises. 5.1.3 Safety precautions The operating of the telecommunication network, including its earthing systems and protection measures, req
48、uires consistent compliance with the safety standards (accident prevention regulations). 5.2 Maintenance of earthing systems The bonding configurations and earthing of telecommunication installations inside buildings is described in ITU-T K.27, ITU-T K.35 and ITU-T K.31 for exchange buildings, remot
49、e sites and customers buildings respectively. Earthing plants have to be inspected in the course of the maintenance of the telecommunication plant. The examination covers control by inspection in accordance with the technical documents where the correct execution and the connection to the EBB or MET is described. Defects have to be corrected immediately. 5.2.1 Visual inspection The following subjects are identified to be inspected: connections to the MET or EBB are available and intact for potential compensat
