1、 International Telecommunication Union ITU-T K.44TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (05/2012) SERIES K: PROTECTION AGAINST INTERFERENCE Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents Basic Recommendation Recommendation ITU-T K.44 Rec. ITU-T
2、K.44 (05/2012) i Recommendation ITU-T K.44 Resistibility tests for telecommunication equipment exposed to overvoltages and overcurrents Basic Recommendation Summary Recommendation ITU-T K.44 seeks to establish fundamental test methods and criteria for the resistibility of telecommunication equipment
3、 to overvoltages and overcurrents. Overvoltages or overcurrents covered by this Recommendation include surges due to lightning on or near the line plant, short-term induction of alternating voltages from adjacent electric power lines or electrified railway systems, earth potential rise due to power
4、faults, and direct contacts between telecommunication lines and power lines. Major changes compared with the 2008 version of this Recommendation include: updating the references; amended Criterion A; revision of the test schematics to improve clarity; adding test schematics for external coaxial cabl
5、e ports; adding multi-conductor test schematics for internal unshielded cables; adding tolerances for waveform generation; addition of ports that rely on insulation coordination for surge protection. History Edition Recommendation Approval Study Group 1.0 ITU-T K.44 2000-02-25 5 2.0 ITU-T K.44 2003-
6、07-29 5 3.0 ITU-T K.44 2008-04-13 5 4.0 ITU-T K.44 2011-11-13 5 5.0 ITU-T K.44 2012-05-29 5 5.1 ITU-T K.44 (2012) Cor. 1 2013-03-16 5 ii Rec. ITU-T K.44 (05/2012) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, inf
7、ormation and communication 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 w
8、orldwide 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 approval of ITU-T Recommendations is covered by the procedure laid down i
9、n 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 “Administration“ is used for conciseness to indicate both a telecommunication adm
10、inistration 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 with the Recommendation is achieved when all of these mandatory pr
11、ovisions 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 required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attentio
12、n 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 Intellectual Property Rights, whether asserted by ITU members or others ou
13、tside 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. However, implementers are cautioned that this may not represent the
14、latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2013 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.44 (05/2012) iii Tab
15、le of Contents Page 1 Scope 1 2 References. 1 3 Definitions, abbreviations and symbols 2 3.1 Definitions 2 3.2 Abbreviations and acronyms 6 3.3 Symbols 8 4 Overvoltage and overcurrent conditions . 8 5 Resistibility requirements . 9 5.1 Basic resistibility requirement 9 5.2 Enhanced resistibility req
16、uirement . 9 6 Equipment boundary . 10 7 Test conditions 10 7.1 Interface ports . 10 7.1.1 Port classification . 10 7.1.2 Interface ports . 10 7.2 Test types 10 7.2.1 Transverse/differential 11 7.2.2 External port to earth 11 7.2.3 External port to external port 11 7.2.4 Internal port to earth . 12
17、7.3 Test conditions 12 7.4 Test schematics . 14 8 Protection coordination . 14 8.1 General . 14 8.2 Lightning 14 8.2.1 Primary SPDs with a switching characteristic 14 8.2.2 Primary SPDs with a clamping characteristic 14 8.3 Power induction, earth potential rise and power contact 15 8.4 Special test
18、protector 15 8.4.1 Switching type protector . 15 8.4.2 Clamping type protector . 15 8.4.3 Multistage modules 15 8.5 Selection of the agreed primary protector 15 9 Acceptance criteria . 15 iv Rec. ITU-T K.44 (05/2012) Page 10 Tests 16 10.1 External symmetric pair port 22 10.1.1 Lightning voltage 22 1
19、0.1.1.1 Single pair . 22 10.1.1.2 Multiple pairs/ports 22 10.1.2 Lightning current 22 10.1.3 Power induction and earth potential rise 22 10.1.4 Mains power contact tests 23 10.2 External coaxial port . 23 10.2.1 Lightning voltage 23 10.2.2 Lightning current differential . 23 10.2.3 Lightning current
20、 shield test . 23 10.2.4 Earth potential rise 24 10.3 External d.c. and a.c. dedicated power feeding ports . 24 10.3.1 Lightning voltage 24 10.3.2 Lightning current 24 10.3.3 Power induction and earth potential rise 24 10.3.4 Mains power contact . 25 10.4 External a.c. mains power port . 25 10.4.1 L
21、ightning voltage 25 10.4.2 Earth potential rise 25 10.4.3 Neutral potential rise 25 10.5 Internal ports . 25 10.5.1 Unshielded cable 25 10.5.2 Shielded cable . 26 10.5.3 Floating d.c. power interface 26 10.5.4 Earthed d.c. power interface . 26 Annex A Test schematics 27 A.1 Introduction 27 A.2 Equip
22、ment . 27 A.2.1 Equipment ports 27 A.2.2 Equipment type . 35 A.2.3 Protection type 35 A.2.4 Equipment conditions and states 35 A.3 Test generators 35 A.4 Waveform generation . 37 A.5 Powering, coupling, decoupling and terminations . 38 A.5.1 General . 38 A.5.2 Tested ports 42 Rec. ITU-T K.44 (05/201
23、2) v Page A.5.2.1 External symmetric pair . 42 A.5.2.2 External coaxial cable port . 42 A.5.2.3 External dedicated power feed port 43 A.5.2.4 Mains ports . 43 A.5.2.5 Internal unshielded cable port 44 A.5.2.6 Internal shielded cable port 45 A.5.2.7 Internal d.c. power interface . 45 A.5.3 Untested p
24、orts . 45 A.5.3.1 External symmetric pair . 45 A.5.3.2 External coaxial cable port . 46 A.5.3.3 External dedicated power feed port 47 A.5.3.4 Mains ports . 48 A.5.3.5 Internal unshielded cable port 49 A.5.3.6 Internal shielded cable port 51 A.5.3.7 Internal d.c. power interface . 52 A.5.4 Protection
25、 elements 53 A.5.4.1 External symmetric pair . 53 A.5.4.2 External coaxial cable port . 54 A.5.4.3 Dedicated power feed port 54 A.5.4.4 Mains power port 54 A.6 Test schematics for different types of ports . 54 A.6.1 Symmetric pair ports 54 A.6.2 Coaxial ports . 54 A.6.3 a.c. or d.c. dedicated power
26、feed ports . 55 A.6.4 Mains power ports 55 A.6.5 Internal cable ports . 55 A.6.6 d.c. power ports 55 A.6.7 Ethernet ports 55 Appendix I Explanations that illustrate test conditions 80 I.1 Testing 80 I.1.1 General . 80 I.1.2 Lightning surge tests . 80 I.1.2.1 Inherent test 81 I.1.2.2 Secondary protec
27、tor coordination test 81 I.1.2.3 Primary protector coordination test 82 I.1.2.4 Uc(max)test . 83 I.1.2.5 Effects for greater than Uc(max)84 I.1.3 Power induction 84 I.1.3.1 Inherent test 86 I.1.3.2 Secondary protector coordination test 87 vi Rec. ITU-T K.44 (05/2012) Page I.1.3.3 Secondary protector
28、 operating test . 87 I.1.3.4 Minimum energy to operate PTCs . 88 I.1.3.5 Primary protector coordination test 89 I.1.3.6 Ua.c.(max)test . 89 I.1.4 Mains power contact . 89 I.1.5 Rationale for test conditions . 91 I.1.5.1 Port to port and port to earth testing . 91 I.1.5.2 Terminations and SPDs on unt
29、ested ports 95 I.1.6 Decoupling networks 96 I.1.6.1 Decoupling inductance . 96 I.1.6.2 Effect of inductance and resistance decoupling elements on digital circuits 99 I.1.7 Mains port testing . 101 I.2 Range of lightning and power induction test levels . 103 I.2.1 Lightning 103 I.2.1.1 Inherent test
30、levels 103 I.2.1.2 Coordination test levels 103 I.2.2 Power induction test levels . 103 I.2.2.1 Inherent test levels 103 I.2.2.2 Inherent/coordination test levels . 104 I.3 Relationship between this Recommendation and other product or product family Recommendations . 104 Appendix II Supplementary in
31、formation for manufacturers and operators 106 II.1 Introduction 106 II.2 Primary protection coordination . 106 II.2.1 Primary protection does not operate . 106 II.2.2 Primary protection does operate . 106 II.2.3 Principles of coordination . 107 II.2.4 Coordination testing of switching and clamping S
32、PDs 109 II.3 MDF voltage at the input of equipment . 110 II.3.1 General . 110 II.3.2 MDF earth wire voltage drop . 112 II.3.3 Earth voltage drop test 114 II.3.3.1 United Kingdoms example of earth voltage drop problem 114 II.3.3.2 Australian example of an earth voltage drop problem at customer premis
33、es 115 II.3.3.3 Australian example of an earth voltage drop problem at a telecommunication centre . 115 II.3.3.4 Possible test for resistibility to earth voltage drop . 115 II.4 Current test on mains ports . 117 Rec. ITU-T K.44 (05/2012) vii Page II.5 Earth and neutral potential rise . 118 II.5.1 Ba
34、ckground . 118 II.5.2 Explanation . 118 II.5.2.1 Earth potential rise 118 II.5.2.2 Neutral potential rise 119 II.5.2.3 Currents that may flow through equipment 120 II.5.2.4 Surge transfer 121 II.6 Special resistibility requirements . 121 II.7 Equipment fire in equipment complying with Recommendation
35、 ITU-T K.21 . 125 II.8 Ethernet . 125 II.8.1 Insulation 125 II.8.2 Ethernet ports 125 II.8.3 Ethernet overvoltages . 126 II.8.3.1 Lightning 126 II.8.3.2 Power fault 127 II.8.3.3 Unscreened twisted pair (UTP) and screened twisted pair (STP) cables . 127 II.8.4 SPCs and SPDs . 127 II.8.5 Insulation ba
36、rriers in series . 128 II.8.6 Increasing the rated impulse voltage 128 II.8.6.1 In-line higher voltage insulation barrier . 128 II.8.6.2 Ethernet SPD 129 Bibliography. 130 Rec. ITU-T K.44 (05/2012) 1 Recommendation ITU-T K.44 Resistibility tests for telecommunication equipment exposed to overvoltage
37、s and overcurrents Basic Recommendation 1 Scope This basic Recommendation describes resistibility tests for all telecommunication equipment against overvoltages and overcurrents for use by network operators and manufacturers. This Recommendation applies to all telecommunication equipment connected t
38、o external or intra-building metallic conductors. It should be read in conjunction with ITU-T K.11 and ITU-T K.39 which deal with the general economic and technical aspects of protection. This Recommendation does not specify either test levels or particular acceptance criteria for specific equipment
39、. The appropriate test levels and test points are contained in the specific product family or product Recommendation. Therefore, this Recommendation has to be used together with the product family or product Recommendation dealing with the resistibility requirements relevant to the equipment to be t
40、ested. If a product family or product Recommendation or clause of it differs from this basic Recommendation, the product family or product Recommendation applies. As product Recommendations are updated, they should be coordinated with and refer to this Recommendation. This Recommendation assumes tha
41、t the earthing and bonding configurations comply with the appropriate Recommendation related to the type of installation. The tests are type tests and, although they are applicable to a complete system, it is recognized that they may be applied to individual items of equipment during development and
42、 design work. In performing the tests, it is necessary to take into account any conditions, either in the unit under test or elsewhere, which may affect the results. Electrostatic discharge (ESD) testing is not covered by this Recommendation and IEC 61000-4-2 should be followed. 2 References The fol
43、lowing 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 were valid. All Recommendations and other references are subject to revision; users of this Rec
44、ommendation 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 Recommendations is regularly published. The reference to a document within this Recommendation does no
45、t give it, as a stand-alone document, the status of a Recommendation. ITU-T K.11 Recommendation ITU-T K.11 (2009), Principles of protection against overvoltages and overcurrents. ITU-T K.12 Recommendation ITU-T K.12 (2010), Characteristics of gas discharge tubes for the protection of telecommunicati
46、ons installations. ITU-T K.20 Recommendation ITU-T K.20 (2011), Resistibility of telecommunication equipment installed in a telecommunications centre to overvoltages and overcurrents. 2 Rec. ITU-T K.44 (05/2012) ITU-T K.21 Recommendation ITU-T K.21 (2011), Resistibility of telecommunication equipmen
47、t installed in customer premises to overvoltages and overcurrents. ITU-T K.27 Recommendation ITU-T K.27 (1996), Bonding configurations and earthing inside a telecommunication building. ITU-T K.28 Recommendation ITU-T K.28 (2012), Parameters of thyristor-based surge protective devices for the protect
48、ion of telecommunication installations. ITU-T K.39 Recommendation ITU-T K.39 (1996), Risk assessment of damages to telecommunication sites due to lightning discharges. ITU-T K.45 Recommendation ITU-T K.45 (2011), Resistibility of telecommunication equipment installed in the access and trunk networks
49、 to overvoltages and overcurrents. IEC 60050-701 IEC 60050-701 (1988), International Electrotechnical Vocabulary. Chapter 701: Telecommunications, channels and networks. IEC 60060-1 IEC 60060-1 (2010), High-voltage test techniques Part 1: General definitions and test requirements. IEC 60065 IEC 60065 (2001), Audio, video and similar electronic apparatus Safety requirements. IEC 60664-2-1 IEC 60664-2-1 (2011), Insulation coordination for equipme
