BS-EN-62305-4-2006.pdf
BRITISH STANDARD BS EN 62305-4:2006 Incorporating corrigendum November 2006 Protection against lightning Part 4: Electrical and electronic systems within structures ICS 29.020; 91.120.40 ? Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 21:36:30 MDTNo reproduction or networking permitted without license from IHS -,-,- BS EN 62305-4:2006 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 September 2006 © BSI 2008 ISBN 978 0 580 60829 2 National foreword This British Standard is the UK implementation of EN 62305-4:2006, incorporating corrigendum November 2006. It is identical with IEC 62305-4:2006. This standard, together with BS EN 62305-1:2006, BS EN 62305-2:2006 and BS EN 62305-3:2006, supersedes BS 6651:1999, which will be withdrawn on 31 August 2008. The UK participation in its preparation was entrusted to Technical Committee GEL/81, Protection against lightning. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments/corrigenda issued since publication DateComments 30 April 2008Implementation of CENELEC corrigendum November 2006, addition of Annex ZA Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 21:36:30 MDTNo reproduction or networking permitted without license from IHS -,-,- EUROPEAN STANDARD EN 62305-4 NORME EUROPÉENNE EUROPÄISCHE NORM February 2006 CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels © 2006 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 62305-4:2006 E ICS 29.020; 91.120.40 English version Protection against lightning Part 4: Electrical and electronic systems within structures (IEC 62305-4:2006) Protection contre la foudre Partie 4: Réseaux de puissance et de communication dans les structures (CEI 62305-4:2006) Blitzschutz Teil 4: Elektrische und elektronische Systeme in baulichen Anlagen (IEC 62305-4:2006) This European Standard was approved by CENELEC on 2006-02-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Rumania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Incorporating corrigendum November 2006 Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 21:36:30 MDTNo reproduction or networking permitted without license from IHS -,-,- Foreword The text of document 81/265/FDIS, future edition 1 of IEC 62305-4, prepared by IEC TC 81, Lightning protection, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 62305-4 on 2006-02-01. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2006-11-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2009-02-01 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 62305-4:2006 was approved by CENELEC as a European Standard without any modification. _ 2 BS EN 62305-4:2006 Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 21:36:30 MDTNo reproduction or networking permitted without license from IHS -,-,- 3 CONTENTS INTRODUCTION.6 1 Scope 8 2 Normative references .8 3 Terms and definitions .9 4 Design and installation of a LEMP protection measures system (LPMS).12 4.1 Design of an LPMS15 4.2 Lightning protection zones (LPZ)15 4.3 Basic protection measures in an LPMS 19 5 Earthing and bonding19 5.1 Earth termination system .20 5.2 Bonding network22 5.3 Bonding bars .27 5.4 Bonding at the boundary of an LPZ 27 5.5 Material and dimensions of bonding components27 6 Magnetic shielding and line routing .28 6.1 Spatial shielding28 6.2 Shielding of internal lines.28 6.3 Routing of internal lines .28 6.4 Shielding of external lines29 6.5 Material and dimensions of magnetic shields29 7 Coordinated SPD protection29 8 Management of an LPMS30 8.1 LPMS management plan30 8.2 Inspection of an LPMS.32 8.3 Maintenance33 Annex A (informative) Basics for evaluation of electromagnetic environment in a LPZ .34 Annex B (informative) Implementation of LEMP protection measures for electronic systems in existing structures .61 Annex C (informative) SPD coordination.78 Annex D (informative) Selection and installation of a coordinated SPD protection96 Bibliography .101 Figure 1 General principle for the division into different LPZ .12 Figure 2 Protection against LEMP Examples of possible LEMP protection measures systems (LPMS)14 Figure 3 Examples for interconnected LPZ .17 Figure 4 Examples for extended lightning protection zones .18 Figure 5 Example of a three-dimensional earthing system consisting of the bonding network interconnected with the earth termination system20 Figure 6 Meshed earth termination system of a plant 21 Annex ZA (normative) Normative references to international publications with their corresponding European publications.102 BS EN 62305-4:2006 Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 21:36:30 MDTNo reproduction or networking permitted without license from IHS -,-,- 4 Figure 7 Utilization of reinforcing rods of a structure for equipotential bonding.23 Figure 8 Equipotential bonding in a structure with steel reinforcement.24 Figure 9 Integration of electronic systems into the bonding network 25 Figure 10 Combinations of integration methods of electronic systems into the bonding network .26 Figure A.1 LEMP situation due to lightning flash .36 Figure A.2 Simulation of the rise of magnetic field by damped oscillations.38 Figure A.3 Large volume shield built by metal reinforcement and metal frames39 Figure A.4 Volume for electrical and electronic systems inside an inner LPZ n 40 Figure A.5 Reducing induction effects by line routing and shielding measures .42 Figure A.6 Example of an LPMS for an office building.43 Figure A.7 Evaluation of the magnetic field values in case of a direct lightning flash45 Figure A.8 Evaluation of the magnetic field values in case of a nearby lightning flash47 Figure A.9 Distance sa depending on rolling sphere radius and structure dimensions 50 Figure A.10 Types of grid-like large volume shields 52 Figure A.11 Magnetic field strength H1/max inside a grid-like shield Type 1 53 Figure A.12 Magnetic field strength H1/max inside a grid-like shield Type 1 53 Figure A.13 Low-level test to evaluate the magnetic field inside a shielded structure .56 Figure A.14 Voltages and currents induced into a loop built by lines57 Figure B.1 Upgrading of LEMP protection measures and electromagnetic compatibility in existing structures.63 Figure B.2 Possibilities to establish LPZs in existing structures.69 Figure B.3 Reduction of loop area using shielded cables close to a metal plate .71 Figure B.4 Example of a metal plate for additional shielding72 Figure B.5 Protection of aerials and other external equipment.74 Figure B.6 Inherent shielding provided by bonded ladders and pipes.75 Figure B.7 Ideal positions for lines on a mast (cross-section of steel lattice mast) .76 Figure C.1 Example for the application of SPD in power distribution systems 79 Figure C.2 Basic model for energy coordination of SPD 81 Figure C.3 Combination of two voltage-limiting type SPDs 82 Figure C.4 Example with two voltage-limiting type MOV 1 and MOV 2 .84 Figure C.5 Combination of voltage-switching type spark gap and voltage-limiting type MOV.85 Figure C.6 Example with voltage-switching type spark gap and voltage-limiting type MOV.86 Figure C.7 Determination of decoupling inductance for 10/350 µs and 0,1kA/µs surges .87 Figure C.8 Example with spark gap and MOV for a 10/350 µs surge89 BS EN 62305-4:2006 Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 21:36:30 MDTNo reproduction or networking permitted without license from IHS -,-,- 5 Figure C.9 Example with spark gap and MOV for 0,1kA/µs surge 91 Figure C.10 Coordination variant I Voltage-limiting type SPD .92 Figure C.11 Coordination variant II Voltage-limiting type SPD 93 Figure C.12 Coordination variant III Voltage-switching type SPD and voltage- limiting type SPD 93 Figure C.13 Coordination variant IV Several SPDs in one element .94 Figure C.14 Coordination according to the “let through energy” method.94 Figure D.1 Surge voltage between live conductor and bonding bar97 BS EN 62305-4:2006 Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 21:36:30 MDTNo reproduction or networking permitted without license from IHS -,-,- 6 INTRODUCTION Lightning as a source of harm is a very high-energy phenomenon. Lightning flashes release many hundreds of mega-joules of energy. When compared with the milli-joules of energy that may be sufficient to cause damage to sensitive electronic equipment in electrical and electronic systems within a structure, it is clear that additional protection measures will be necessary to protect some of this equipment. The need for this International Standard has arisen due to the increasing cost of failures of electrical and electronic systems, caused by electromagnetic effects of lightning. Of particular importance are electronic systems used in data processing and storage as well as process control and safety for plants of considerable capital cost, size and complexity (for which plant outages are very undesirable for cost and safety reasons). Lightning can cause different types of damage in a structure, as defined in IEC 62305-2: D1 injuries to living beings due to touch and step voltages; D2 physical damage due to mechanical, thermal, chemical and explosive effects; D3 failures of electrical and electronic systems due to electromagnetic effects. IEC 62305-3 deals with the protection measures to reduce the risk of physical damage and life hazard, but does not cover the protection of electrical and electronic systems. This Part 4 of IEC 62305 therefore provides information on protection measures to reduce the risk of permanent failures of electrical and electronic systems within structures. Permanent failure of electrical and electronic systems can be caused by the lightning electromagnetic impulse (LEMP) via: a) conducted and induced surges transmitted to apparatus via connecting wiring; b) the effects of radiated electromagnetic fields directly into apparatus itself. Surges to the structure can be generated externally or internally: surges external to the structure are created by lightning flashes striking incoming lines or the nearby ground, and are transmitted to electrical and electronic systems via these lines; surges internal to the structure are created by lightning flashes striking the structure or the nearby ground. The coupling can arise from different mechanisms: resistive coupling (e.g. the earth impedance of the earth termination system or the cable shield resistance); magnetic field coupling (e.g. caused by wiring loops in the electrical and electronic system or by inductance of bonding conductors); electric field coupling (e.g. caused by rod antenna reception). NOTE The effects of electric field coupling are generally very small when compared to the magnetic field coupling and can be disregarded. BS EN 62305-4:2006 Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 21:36:30 MDTNo reproduction or networking permitted without license from IHS -,-,- 7 Radiated electromagnetic fields can be generated via the direct lightning current flowing in the lightning channel, the partial lightning current flowing in conductors (e.g. in the down conductors of an external LPS according to IEC 62305-3 or in an external spatial shield according to this standard). BS EN 62305-4:2006 Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy Licensee=Boeing Co/5910770001 Not for Resale, 08/14/2008 21:36:30 MDTNo reproduction or networking permitted without license from IHS -,-,- 8 PROTECTION AGAINST LIGHTNING Part 4: Electrical and electronic systems within structures 1 Scope This part of IEC 62305 provides information for the design, installation, inspection, maintenance and testing of a LEMP protection measures system (LPMS) for electrical and electronic systems within a structure, able to reduce the risk of permanent failures due to lightning electromagnetic impulse. This standard does not c
