SANS 61643-12-2009 Low-voltage surge protective devices Part 12 Surge protective devices connected to low-voltage power distribution systems - Selection and application principles《.pdf

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1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA

2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any

3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-22438-7 SANS 61643-12:2009 Edition 2 IEC 61643-12:2008 Edition 2 SOUTH AFRICAN NATIONAL STANDARD Low-voltage surge protective devices Part

4、 12: Surge protective devices connected to low-voltage power distribution systems Selection and application principles This national standard is the identical implementation of IEC 61643-12:2008 and is adopted with the permission of the International Electrotechnical Commission. WARNING Can only be

5、used in conjunction with SANS 61643-1. Published by SABS Standards Division 1 Dr Lategan Road Groenkloof Private Bag X191 Pretoria 0001 Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS This standard may only be used and printed by approved subscription and freemailing clients of the SAB

6、S. SANS 61643-12:2009 Edition 2 IEC 61643-12:2008 Edition 2 Table of changes Change No. Date Scope National foreword This South African standard was approved by National Committee SABS SC 67E, Electricity distribution systems and components Electricity distribution, in accordance with procedures of

7、the SABS Standards Division, in compliance with annex 3 of the WTO/TBT agreement. This SANS document was published in April 2009. This SANS document supersedes SANS 61643-12:2003 (edition 1). This standard may only be used and printed by approved subscription and freemailing clients of the SABS. IEC

8、 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 rsea

9、ux de distribution basse tension Principes de choix et dapplication INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE 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

10、 de la Commission Electrotechnique Internationale SANS 61643-12:2009This standard may only be used and printed by approved subscription and freemailing clients of the SABS. 2 61643-12 IEC:2008 CONTENTS FOREWORD.8 0 Introduction 11 0.1 General .11 0.2 Keys to understanding the structure of this stand

11、ard .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 power distribution systems.26 4.1.1 Lightning overvolt

12、ages 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 Classification of SPDs .31 5.3.1 SPD: classification.31 5

13、.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 related to power-frequency voltages35 5.5.2 Information rela

14、ted 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 current I Land to voltage drop (for two- port SPDs or one-p

15、ort 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 by SPDs.40 6.1.1 Possible modes of protection and insta

16、llation 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 regarding location of the SPD depending on the classes of te

17、st .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 SANS 61643-12:2009This standard may only be used and printed by approved subscription and freemailing clients of the SABS.61643-12 IEC:

18、2008 3 6.2.3 Prospective life and failure mode.53 6.2.4 Interaction 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

19、 counters 57 6.3.3 Status indicator .57 7 Risk analysis 57 Annex A (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

20、of SPD 59 A.1.4 Additional equipment and fittings.60 A.1.5 Any special 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

21、 for assessment of U res 61 A.3.3 Influence of a back filter on determination 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 withs

22、tand capability test in conjunction with overcurrent protection (if 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

23、 the system 64 B.2 Relationship between U pand U cfor a ZnO varistor64 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 syste

24、ms67 C.2.3 Induced overvoltages in LV distribution systems68 C.2.4 Overvoltages 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-

25、limiting fuses).71 Annex D (informative) Partial lightning current calculations72 Annex E (informative) TOV in the low-voltage system due to faults between high- voltage systems and earth 75 SANS 61643-12:2009This standard may only be used and printed by approved subscription and freemailing clients

26、 of the SABS. 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 installations due to earth faults in a high-voltage system 76 E.2.2 Characteristics of the high-voltage system 77 E.2.

27、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 temporary overvoltages for the US TN C-S system88 Annex F (informative) Coordination rules and principles.90 F.1 Gen

28、eral 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 gap-based SPD and a ZnO varistor based SPD.93 F.3.1 General .93 F.3.2 Example of the calculation of the estimat

29、ed 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) method.96 F.5.1 General .96 F.5.2 Method97 Annex G (informative) Examples of application 99 G.1 Domestic applicati

30、on 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 stresses .111 I.1 Lightning overvoltages and currents 4.1.1 111 I.1.1 Aspects of the power distribution system th

31、at 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) Criteria for selection of SPDs.114 J.1 U Ttemporary overvoltage characteristic 5.5.1.2.114 J.2 SPD failure modes

32、 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 the oscillation phenomena on the protective distance 6.1.2 126 K.1.3 Protection zone concept 6.1.6 .127 K.2 Sel

33、ection of SPDs 129 K.2.1 Selection of U c6.2.1 .129 K.2.2 Coordination problems 6.2.6.2.130 SANS 61643-12:2009This standard may only be used and printed by approved subscription and freemailing clients of the SABS.61643-12 IEC:2008 5 K.2.3 Practical cases 6.2.6.3 132 Annex L (informative) Risk analy

34、sis .133 L.1 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

35、 power distribution 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 withsta

36、nd 150 P.3 Fuse 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 O

37、utput voltage 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 r

38、esversus I for 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

39、 Flowchart for 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

40、 fault in the 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 SANS 61643-12:2009This standard may only be used and printed by approved subscription and freemailing clients of the SABS. 6 61643-12 IEC:2008 Fig

41、ure 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 e186 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 v

42、aristors with different nominal discharge currents.92 Figure F.3 Example of coordination of a gap-based SPD and a ZnO varistor based SPD95 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 Circu

43、itry 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 (TT system).112 Figure J.1 Typical curve for U Tof an SPD .114 Figure J.2 Internal disconnector in the case of a two-port SPD 1

44、15 Figure J.3 Use of parallel SPDs .116 Figure K.1 Installation of surge protective devices in TN-systems 118 Figure K.2a Connection Type 1.119 Figure K.2b Connection Type 2120 Figure K.2 Installation of surge protective devices in TT-systems (SPD downstream of the RCD) 120 Figure K.3 Installation o

45、f surge protective devices in TT-systems (SPD upstream of the RCD) 121 Figure K.4 Installation of surge protective devices in IT-systems without distributed neutral 122 Figure K.5 Typical installation of SPD at the entrance of the installation in case of a TN C-S system .123 Figure K.6 General way o

46、f installing one-port SPDs.124 Figure K.7 Examples of acceptable and unacceptable SPD installations regarding EMC aspects 125 Figure K.8 Physical and electrical representations of a system where equipment being protected is separated from the SPD giving protection 126 Figure K.9 Possible oscillation

47、 between a ZnO SPD and the equipment to be protected 126 Figure K.10 Example of voltage doubling .127 Figure K.11 Subdivision of a building into protection zones128 Figure K.12a Residual voltage on varistors .130 Figure K.12b Sharing of current between two varistors 131 Figure K.12 Coordination of t

48、wo ZnO varistors:131 Figure N.1 A wiring diagram of an SPD connected on the load side of the main incoming isolator via a separate isolator (which could be included in the SPD enclosure).138 SANS 61643-12:2009This standard may only be used and printed by approved subscription and freemailing clients

49、 of the SABS.61643-12 IEC:2008 7 Figure N.2 SPD connected to the nearest available outgoing MCB to the incoming supply (TNS installation typically seen in the UK) .139 Figure N.3 A single line-wiring diagram of an SPD connected in shunt on the first outgoing way of the distribution panel via a fuse (or MCB)140 Figure N.4 SPD connected to the nearest available circuit breaker o