1、 IEC 61643-12 Edition 2.0 2008-11 INTERNATIONAL STANDARD NORME INTERNATIONALE Low-voltage surge protective devices Part 12: Surge protective devices connected to low-voltage power distribution systems Selection and application principles Parafoudres basse tension Partie 12: Parafoudres connects aux
2、rseaux de distribution basse tension Principes de choix et dapplication IEC 61643-12:2008 THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2008 IEC, Geneva, Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any m
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16、taires sur cette publication ou si vous avez des questions, visitez le FAQ du Service clients ou contactez-nous: Email: csciec.ch Tl.: +41 22 919 02 11 Fax: +41 22 919 03 00 IEC 61643-12 Edition 2.0 2008-11 INTERNATIONAL STANDARD NORME INTERNATIONALE Low-voltage surge protective devices Part 12: Sur
17、ge protective devices connected to low-voltage power distribution systems Selection and application principles Parafoudres basse tension Partie 12: Parafoudres connects aux rseaux de distribution basse tension Principes de choix et dapplication INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION EL
18、ECTROTECHNIQUE INTERNATIONALE XG ICS 29.240; 29.240.10 PRICE CODE CODE PRIX ISBN 2-8318-1014-9 Registered trademark of the International Electrotechnical Commission Marque dpose de la Commission Electrotechnique Internationale 2 61643-12 IEC:2008 CONTENTS FOREWORD.8 0 Introduction 11 0.1 General .11
19、 0.2 Keys to understanding the structure of this standard .11 1 Scope.13 2 Normative references .13 3 Terms, definitions and abbreviated terms .14 3.1 Terms and definitions 14 3.2 List of abbreviations and acronyms used in this standard 25 4 Systems and equipment to be protected .26 4.1 Low-voltage
20、power distribution systems.26 4.1.1 Lightning overvoltages and currents 27 4.1.2 Switching overvoltages28 4.1.3 Temporary overvoltages U TOV .28 4.2 Characteristics of the equipment to be protected.30 5 Surge protective devices 31 5.1 Basic functions of SPDs 31 5.2 Additional requirements.31 5.3 Cla
21、ssification of SPDs .31 5.3.1 SPD: classification.31 5.3.2 Typical design and topologies32 5.4 Characteristics of SPDs.33 5.4.1 Service conditions described in IEC 61643-1.33 5.4.2 List of parameters for SPD selection34 5.5 Additional information on characteristics of SPDs35 5.5.1 Information relate
22、d to power-frequency voltages35 5.5.2 Information related to surge currents .36 5.5.3 Information related to voltage protection level provided by SPDs.37 5.5.4 Information related to SPD failure modes 39 5.5.5 Information related to short-circuit withstand .40 5.5.6 Information related to load curre
23、nt I Land to voltage drop (for two- port SPDs or one-port SPDs with separate input and output terminals) 40 5.5.7 Information related to change of characteristics of SPDs .40 6 Application of SPDs in low-voltage power distribution systems .40 6.1 Installation and its effect on the protection given b
24、y SPDs.40 6.1.1 Possible modes of protection and installation 41 6.1.2 Influence of the oscillation phenomena on the protective distance (called separation distance in some countries) 43 6.1.3 Influence of the connecting lead length44 6.1.4 Need for additional protection45 6.1.5 Consideration regard
25、ing location of the SPD depending on the classes of test .46 6.1.6 Protection zone concept 46 6.2 Selection of SPD .48 6.2.1 Selection of U c , U T , I n , I imp , I maxand U ocof the SPD49 6.2.2 Protective distance 52 61643-12 IEC:2008 3 6.2.3 Prospective life and failure mode.53 6.2.4 Interaction
26、between SPDs and other devices.53 6.2.5 Choice of the voltage protection level U p .54 6.2.6 Coordination between the chosen SPD and other SPDs 55 6.3 Characteristics of auxiliary devices57 6.3.1 Disconnecting devices.57 6.3.2 Event counters 57 6.3.3 Status indicator .57 7 Risk analysis 57 Annex A (
27、informative) Typical information given with inquiries and tenders and explanation of testing procedures .59 A.1 Information given with inquiries 59 A.1.1 System data 59 A.1.2 SPD application considerations .59 A.1.3 Characteristics of SPD 59 A.1.4 Additional equipment and fittings.60 A.1.5 Any speci
28、al abnormal conditions .60 A.2 Information given with tender60 A.3 Explanation of testing procedures used in IEC 61643-160 A.3.1 Determination of U resfor SPDs tested according to class I and class II tests60 A.3.2 Impulse waveshape for assessment of U res 61 A.3.3 Influence of a back filter on dete
29、rmination of U res .61 A.3.4 Operating duty test for SPDs.61 A.3.5 TOV failure test .62 A.3.6 Differences in the testing conditions of Type 1 (test class I), 2 (test class II) and 3 (test class III) SPDs.62 A.3.7 Short-circuit withstand capability test in conjunction with overcurrent protection (if
30、any) 63 Annex B (informative) Examples of relationship between U cand the nominal voltage used in some systems and example of relationship between U pand U cfor ZnO varistor .64 B.1 Relationship between U cand the nominal voltage of the system 64 B.2 Relationship between U pand U cfor a ZnO varistor
31、64 Annex C (informative) Environment Surge voltages in LV systems66 C.1 General 66 C.2 Lightning overvoltages66 C.2.1 Surges transferred from MV to the LV system67 C.2.2 Overvoltages caused by direct flashes to LV distribution systems67 C.2.3 Induced overvoltages in LV distribution systems68 C.2.4 O
32、vervoltages caused by flashes to a lightning protection systems or an area of close vicinity68 C.3 Switching overvoltages.69 C.3.1 General description .70 C.3.2 Circuit-breaker and switch operations70 C.3.3 Fuse operations (current-limiting fuses).71 Annex D (informative) Partial lightning current c
33、alculations72 Annex E (informative) TOV in the low-voltage system due to faults between high- voltage systems and earth 75 4 61643-12 IEC:2008 E.1 General 75 E.2 Example of a TT system Calculation of the possible temporary overvoltages.76 E.2.1 Possible stresses on equipment in low-voltage installat
34、ions due to earth faults in a high-voltage system 76 E.2.2 Characteristics of the high-voltage system 77 E.2.3 TOV in low-voltage system due to faults in the high-voltage system 77 E.2.4 Conclusions 78 E.3 Values of the temporary overvoltages according to IEC 60364-4-44 .78 E.4 Values of the tempora
35、ry overvoltages for the US TN C-S system88 Annex F (informative) Coordination rules and principles.90 F.1 General 90 F.2 Analytical studies: simple case of the coordination of two ZnO varistor based SPDs 90 F.2.1 General .90 F.2.2 Conclusion 92 F.3 Analytical study: case of coordination between a ga
36、p-based SPD and a ZnO varistor based SPD.93 F.3.1 General .93 F.3.2 Example of the calculation of the estimated values required for a decoupling inductance between a gap and a varistor.94 F.3.3 Conclusion 95 F.4 Analytical study: general coordination of two SPDs 95 F.5 Let-through energy (LTE) metho
37、d.96 F.5.1 General .96 F.5.2 Method97 Annex G (informative) Examples of application 99 G.1 Domestic application 99 G.2 Industrial application 101 G.3 Presence of a lightning protection system.105 Annex H (informative) Examples of application of the risk analysis 107 Annex I (informative) System stre
38、sses .111 I.1 Lightning overvoltages and currents 4.1.1 111 I.1.1 Aspects of the power distribution system that affect the need for an SPD111 I.1.2 Sharing of surge current within a structure 111 I.2 Switching overvoltages 4.1.2112 I.3 Temporary overvoltages U TOV4.1.3 .113 Annex J (informative) Cri
39、teria for selection of SPDs.114 J.1 U Ttemporary overvoltage characteristic 5.5.1.2.114 J.2 SPD failure modes 5.5.4.114 Annex K (informative) Application of SPDs 117 K.1 Location and protection given by SPDs 6.1.117 K.1.1 Possible modes of protection and installation 6.1.1 .117 K.1.2 Influence of th
40、e oscillation phenomena on the protective distance 6.1.2 126 K.1.3 Protection zone concept 6.1.6 .127 K.2 Selection of SPDs 129 K.2.1 Selection of U c6.2.1 .129 K.2.2 Coordination problems 6.2.6.2.130 61643-12 IEC:2008 5 K.2.3 Practical cases 6.2.6.3 132 Annex L (informative) Risk analysis .133 L.1
41、Group A Environmental133 L.2 Group B Equipment and facilities.133 L.3 Group C Economics and service interruption .134 L.4 Group D Safety135 L.5 Group E Cost of protection 135 Annex M (informative) Immunity vs. insulation withstand136 Annex N (informative) Examples of SPD installation in power distri
42、bution boards in some countries .138 Annex O (informative) Coordination when equipment has both signalling and power terminals.143 Annex P (informative) Short circuit backup protection and surge withstand 150 P.1 Introduction 150 P.2 Information single shot 8/20 and 10/350 fuses withstand 150 P.3 Fu
43、se Influencing factors (reduction) for preconditioning and operating duty test .151 P.4 Specific examples with estimated range of factors for reduction of single shot fuse withstand151 Bibliography153 Figure 1 Examples of one-port SPDs .19 Figure 2 Examples of two-port SPDs20 Figure 3 Output voltage
44、 response of one-port and two-port SPDs to a combination wave impulse22 Figure 4 Maximum values of U TOVaccording to IEC 60634-4-4430 Figure 5 Examples of components and combinations of components .33 Figure 6 Relationship between U p , U 0 , U cand U cs 35 Figure 7 Typical curve of U resversus I fo
45、r ZnO varistors.38 Figure 8 Typical curve for a spark gap .39 Figure 9 Flowchart for SPD application 41 Figure 10 Connection Type 1 (CT1) .42 Figure 11 Connection Type 2 (CT2) .42 Figure 12 Influence of SPD connecting lead lengths 45 Figure 13 Need for additional protection 46 Figure 14 Flowchart fo
46、r the selection of an SPD 48 Figure 15 U Tand U TOV 51 Figure 16 Typical use of two SPDs Electrical drawing .55 Figure D.1 Simple calculation of the sum of partial lightning currents into the power distribution system72 Figure E.1 Temporary power-frequency overvoltage caused by an earth fault in the
47、 high-voltage system76 Figure E.2 TN systems.79 Figure E.3 TT systems.80 Figure E.4 IT system, example a81 Figure E.5 IT system, example b82 6 61643-12 IEC:2008 Figure E.6 IT system, example c1 83 Figure E.7 IT system, example c2 84 Figure E.8 IT system, example d85 Figure E.9 IT system, example e18
48、6 Figure E.10 IT system, example e287 Figure E.11 US TN-C-S System .88 Figure F.1 Two ZnO varistors with the same nominal discharge current .91 Figure F.2 Two ZnO varistors with different nominal discharge currents.92 Figure F.3 Example of coordination of a gap-based SPD and a ZnO varistor based SPD
49、95 Figure F.4 LTE Coordination method with standard pulse parameters.96 Figure G.1 Domestic installation 100 Figure G.2 Industrial installation 103 Figure G.3 Circuitry of industrial installation.104 Figure G.4 example for a lightning protection system.106 Figure I.1 Example of diversion of lightning current into the external services (