BS EN 50536:2011+A1:2012 Incorporating corrigendum June 2011 BSI Standards Publication Protection against lightning — Thunderstorm warning systems BRITISH STANDARD BS EN 50536:2011+A1:2012 National foreword This British Standard is the UK implementation of EN 50536:2011+A1:2012, incorporating corrigendum June 2011 It supersedes BS EN 50536:2011, which is withdrawn The start and finish of text introduced or altered by corrigendum is indicated in the text by tags Text altered by CENELEC corrigendum June 2011 is indicated in the text by ˆ‰ The start and finish of text introduced or altered by amendment is indicated in the text by tags Tags indicating changes to CENELEC text carry the number of the CENELEC amendment For example, text altered by CENELEC amendment A1 is indicated by !" 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 © The British Standards Institution 2013 Published by BSI Standards Limited 2013 ISBN 978 580 78808 ICS 07.060 Compliance with a British Standard cannot confer immunity from legal obligations This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 August 2011 Amendments/corrigenda issued since publication Date Text affected 31 July 2011 Implementation of CENELEC corrigendum June 2011 28 February 2013 Implementation of CENELEC amendment A1:2012 EUROPEAN STANDARD EN 50536:2011+A1 NORME EUROPÉENNE EUROPÄISCHE NORM October 2012 Incorporating corrigendum June 2011 ICS 07.060 English version Protection against lightning Thunderstorm warning systems Protection contre la foudre Dispositif de détection d'orage Blitzschutz Gewitterwarnsysteme This European Standard was approved by CENELEC on 2011-02-14 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, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels © 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members Ref No EN 50536:2011 E BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) -2- Foreword This European Standard was prepared by the Technical Committee CENELEC TC 81X, Lightning protection The text of the draft was submitted to the formal vote and was approved by CENELEC as EN 50536 on 2011-02-14 Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights CEN and CENELEC shall not be held responsible for identifying any or all such patent rights The following dates are proposed: – – latest date by which the amendment has to be implemented at national level by publication of an identical national standard or by endorsement latest date by which the national standards conflicting with the amendment have to be withdrawn (dop) 2012-02-14 (dow) 2014-02-14 Foreword to amendment A1 This document (EN 50536:2011/A1:2012) has been prepared by CLC/TC 81X "Lightning protection" The following dates are fixed: • latest date by which this document has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2013-09-19 • latest date by which the national standards conflicting with this document have to be withdrawn (dow) 2015-09-19 Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent rights -3- BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) Contents Introduction - - 1 2 General - - 1.1 Object - - 1.2 Scope - - Normative references - - 3 Terms and definitions - - 4 Thunderstorm phases and detectable phenomena for alarming - 11 - 4.1 Introduction - 11 - 4.2 Phase – Initial phase (Cumulus stage) - 11 - 4.3 Phase – Growth phase - 12 - 4.4 Phase – Mature phase - 12 - 4.5 Phase – Dissipation phase - 12 - Classification of thunderstorm detection devices and their properties - 12 - 5 6 7 Alarm method - 14 - 6.1 General - 14 - 6.2 Areas - 14 - 6.3 Alarm triggering - 15 - 6.4 Alarm information delivery - 17 - Installation and maintenance - 17 - 8 Alarm evaluation - 17 - 8.1 General - 17 - 8.2 Evaluation of systems by using lightning location data - 19 - 8.3 Fine tuning of TWS by processing archived data - 19 - 9 Thunderstorms Warning Systems application guide - 20 - 9.1 General - 20 - 9.2 Procedure - 20 - Annex A (informative) Overview of the lightning phenomena - 23 - A.1 Origin of thunderclouds and electrification - 23 - A.2 Lightning phenomena - 24 - A.3 Electrical thunderstorm and lightning characteristics useful for prevention - 25 - Annex B (informative) Thunderstorm detection techniques - 27 - B.1 Introduction - 27 - B.2 Detection techniques and parameters to qualify a sensor - 27 - B.3 Location techniques - 28 - B.4 Thunderstorm detectors evaluation - 30 - B.5 Choosing a thunderstorm detection system - 30 - Annex C (informative) Thunderstorms Warning Systems application examples - 31 - C.1 Example n° – TELECOMUNICATION TOWER - 31 - C.2 Example n° – GOLF COURSE - 33 - C.3 Example n° – WIND TURBINE FARM (including its maintenance) - 35 - Annex D (informative) Catalogue of possible recommended preventive actions to be taken - 38 - Annex E (informative) Example of TWS evaluation on a wind turbine site - 41 - Bibliography - 43 - BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) -4- Figures Figure ― Examples of different target shapes - 14 - Figure ― Example of the distribution of the coverage area (CA), the monitoring area (MA) and the target area - 15 - Figure ― Example of an alarm a) Locations of the lightning related events (LRE) in the defined areas (coverage area CA, monitoring area MA, surrounding area SA, and target ); b) temporal occurrence of the lightning related events (LRE); and c) timing of the alarm according to the occurrence of the lightning related events (LRE) in the defined areas Note: surrounding area used in this figure is defined in 8.2) - 16 - Figure ― Introduction of the surrounding area (SA) for evaluation purposes - 19 - Figure A.1 ― Adapted from Krehbiel (1986) - 23 - Figure A.2 ― Standard lightning classifications - 24 - Figure D.1 ― Possible preventive steps - 40 - Figure E.1 ― CG lightning activity around the wind turbine for a period of eight years (a total of 480 strokes were reported) - 41 - Tables Table ― Lightning detector properties - 13 - Table ― Contingency table - 18 - Table ― Identification of hazardous situations - 21 - Table ― Loss concerning people - 21 - Table ― Loss concerning goods - 21 - Table ― Loss concerning services - 22 - Table ― Loss concerning environment - 22 - Table ― Risk control - 22 - Table C.1 ― Identification of hazardous situations - 31 - Table C.2 ― Loss concerning people - 32 - Table C.3 ― Loss concerning goods - 32 - Table C.4 ― Loss concerning services - 32 - Table C.5 ― Loss concerning environment - 32 - Table C.6 ― Risk control - 33 - Table C.7 ― Identification of hazardous situations - 33 - Table C.8 ― Loss concerning people - 34 - Table C.9 ― Loss concerning goods - 34 - Table C.10 ― Loss concerning services - 34 - Table C.11 ― Loss concerning environment - 34 - Table C.12 ― Risk control - 35 - Table C.13 ― Identification of hazardous situations - 35 - Table C.14 ― Loss concerning people - 36 - Table C.15 ― Loss concerning goods - 36 - Table C.16 ― Loss concerning services - 36 - Table C.17 ― Loss concerning environment - 36 - Table C.18 ― Risk control - 37 - Table D.1 ― Possible preventive steps - 39 - -5- BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) Table E.1 ― Results of TWS evaluation based on archived lightning date for an 8-year period (2000 to 2007), when some of the key parameters (size of MA, trigger parameters and dwell time) were varied - 42 - BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) -6- Introduction Natural atmospheric electric activity and in particular cloud-to-ground lightning poses a serious threat to living beings and property Every year severe injuries and even deaths of humans are caused as a direct or indirect result of lightning: – sport, cultural and political events attracting large concentrations of people may have to be suspended and evacuated in the case of a risk of thunderstorm; – power outages and unplanned interruptions of production processes; – the wider use of electrical components that are sensitive to the effects of lightning (in industry, transportation and communication) has led to a steady increase in the number of accidents per year In order to reduce this number of accidents and important material losses, it may be necessary in some circumstances, to disconnect certain equipment from any incoming installations; – thunderstorms could interrupt all kinds of traffic (people, energy, information, etc.); – activities with an environmental risk, for example: handling of sensitive, inflammable, explosive or chemical products Lightning is also one of the causes of fires During the last decades, technical systems and systems devoted to real-time monitoring of natural atmospheric electric activity and lightning have experienced an extraordinary development These systems can provide high quality and valuable information in real-time of the thunderstorm occurrence, making it possible to achieve information which can be extremely valuable if coordinated with a detailed plan of action Although this information allows the user to adopt anticipated temporary preventive measures, it should be noted, however, that all the measures to be taken based on monitoring information are the responsibility of the system user according to the relevant regulations The effectiveness will depend largely on the risk situation involved and the planned decisions to be taken This document shows a list of possible actions that is, however, merely of an informative nature It should be pointed out that lightning and thunderstorms, as any natural phenomenon, are subject to statistical uncertainty This means that it is not possible to achieve 100 % precise information on when and where lightning will strike Standards dealing with lightning protection methods to limit lightning damages already exist They not cover other potentially dangerous situations related to thunderstorms and lightning, that can be dynamically prevented or reduced by temporary measures whose origin is a preventive alert provided by a detection system -7- 1.1 BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) General Object This European Standard provides information on the characteristics of thunderstorm warning systems and information for the evaluation of the !usefulness" of lightning real time data and/or storm electrification data in order to implement lightning hazard preventive measures 1.2 Scope This European Standard provides the basic requirements of sensors and networks collecting accurate data of the relevant parameters informing in real-time about lightning tracking and range It describes the application of the data collected by these sensors and networks in the form of warnings and historical data This European Standard applies to the use of information from thunderstorm warning systems (which are systems or equipment which provide real-time information) on atmospheric electrical activity in order to monitor for preventive means The scope of this document is providing: – a general description of the available lightning and storm electrification hazard warning systems; – a classification of thunderstorm detection devices and properties; – guidelines for alarming methods; – a procedure to determine the thunderstorm information !usefulness;" – some examples of possible preventive actions (only for information) A non-exhaustive list of activities to which this European Standard might apply is given below: – people in open areas: maintenance people, labour, sports or other open-air activities, competitions, crowded events, agricultural activities, farms and fisheries; – wind farms, larger solar power systems, power lines, etc.; – occupational health and safety prevention; – safeguard sensitive equipment: computer systems, electric or electronic systems, emergency systems, alarms and safety; – prevention of losses in operations and industrial processes; – prevention of serious accidents involving dangerous substances (e.g flammable, radioactive, toxic, and explosive); – prevention in determined environments or activities with special danger of electrostatic discharges (e.g space and flight vehicle operations); – operations in which the continuity of the basic services is needed to be guaranteed (e.g telecommunications, the generation, transport and distribution of energy, sanitary services and emergency services); – infrastructures: ports, airports, railroads, motorways and cableways; – civil defence of the environment: forest fires, land slide and floods; – managing traffic (e.g airplanes) or wide networks (e.g power lines, telecommunication lines) may also benefits from having early detection of thunderstorms BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) -8- !The following aspects are outside of this European Standard: a) lightning protection which is covered in their corresponding European standards and regulations; b) other thunderstorm related phenomena such as rain, hail, wind, etc.; c) satellite and radar thunderstorm detection techniques; d) this European Standard does not address any details on lightning and/or storm electrification hazard preventive actions." Normative references The following referenced documents are indispensable for the application of this document For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies EN 62305 series, Protection against lightning (IEC 62305 series) Terms and definitions For the purposes of this document, the following terms and definitions apply 3.1 alarm information indicating that the target is potentially subject of being affected by thunderstorms and the accompanying lightning related events 3.2 cloud flash lightning flash that never reaches the ground NOTE It can be an intra-cloud, a cloud-to-cloud or a cloud-to-air flash NOTE By extension the term “intra-cloud” (IC) lightning sometimes encompasses the whole cloud flash family 3.3 lightning flash to earth CG flash electrical discharge of atmospheric origin between cloud and earth consisting of one or more strokes [EN 62305-1:2011] 3.4 coverage area CA area where a given warning equipment has a sufficient detection efficiency and/or accuracy to elaborate a warning 3.5 detection efficiency DE percentage of actual lightning discharges that are detected and located by a sensor or a network NOTE As cloud to ground flashes are often composed of several strokes there is a difference between flash detection efficiency (DEf) and stroke detection efficiency (DEs) A flash is reported (detected) if at least one stroke (first or subsequent) is detected and therefore DEf is always equal or higher than DEs BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) C.1.2 - 32 - Step 2: Determination of type of loss For each selected situation of Table C.1, evaluate the different losses concerning people (Table C.2), goods (Table C.3), services (Table C.4) and environment (Table C.5) to determine the heaviness degree (I, II, III or 0) Table C.2 ― Loss concerning people Loss Heaviness degree Loss of human life I Serious injuries to people II Minor injuries to people III No injuries to people The loss of human life is not considered in this example Table C.3 ― Loss concerning goods Loss Heaviness degree Loss of valuable goods I Loss of common value goods II Minor losses of goods III No loss There is a risk of a direct strike to telecommunication equipment and there is also a risk of perturbations induced by nearby lightning Table C.4 ― Loss concerning services Loss Heaviness degree Loss of valuable services I Loss of common services II Minor losses of services III No loss Vital equipment can be destroyed by direct and nearby lightning thus interrupting the service Table C.5 ― Loss concerning environment Loss Heaviness degree Environmental disaster I Damages to environment II Minor environmental damage III No loss BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) - 33 - C.1.3 Step 3: Risk control The loss of human life is not considered in this example The loss of goods and service due to direct strike cannot be completely eliminated but it is possible to isolate the tower (disconnect from the power network, etc.) in order to limit the risk by nearby lightning in the case that the remaining risk ˆafter applying lightning protection according to EN 62305 series or other ! European " standards is not acceptable.‰ Table C.6 ― Risk control Loss heaviness Implementation of adequate TWS (as result of Tables C.4 to C.5) C.2 C.2.1 I Very highly recommended II Highly recommended III Recommended Not recommended Example n° – GOLF COURSE Step 1: Identification of hazardous situations Identify one or several hazardous situations among the different possibilities of Table C.7 In the case of a situation not covered in the table, select “Other situations” Table C.7 ― Identification of hazardous situations No Situation People in open areas without an appropriated lightning protected shelter available ˆ(according to EN 62305 series !text deleted"):‰ outdoor activities, sports (football, golf, etc.), competitions, crowded events, farming, ranching or fishing activities, beaches, leisure areas Safeguard of sensitive goods: computer systems, electrical or electronic controls, emergency, alarm and safety systems Losses in operations and industrial processes Structures containing dangerous substances (inflammable, radioactive, toxic and explosive materials) Basic services whose continuity, quality or fast recovery shall be guaranteed (telecommunications, energy generation, transport and distribution, sanitary and emergency services) Infrastructures: ports, airports, railroads, roads, motorways, cableways Safety at workplace (activities that imply a risk at workplace in case of a thunderstorm) Zones that need civil or environmental protection: prevention of forest fires, etc Buildings, transport or facilities with their external areas open to the public 10 Other situations BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) C.2.2 - 34 - Step 2: Determination of type of loss For each selected situation of Table C.7, evaluate the different losses concerning people (Table C.8), goods (Table C.9), services (Table C.10) and environment (Table C.11) to determine the heaviness degree (I, II, III or 0) Table C.8 ― Loss concerning people Loss Heaviness degree Loss of human life I Serious injuries to people II Minor injuries to people III No injuries to people During thunderstorm activity, there is a potential lightning threat for everyone outside in the open area of the golf course Additional information can be found in reference [7] Table C.9 ― Loss concerning goods Loss Heaviness degree Loss of valuable goods I Loss of common value goods II Minor losses of goods III No loss Table C.10 ― Loss concerning services Loss Heaviness degree Loss of valuable services I Loss of common services II Minor losses of services III No loss Table C.11 ― Loss concerning environment Loss Heaviness degree Environmental disaster I Damages to environment II Minor environmental damage III No loss BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) - 35 - C.2.3 Step 3: Risk control The loss concerning people can be reduced by avoiding having people exposed to the lightning threat Table C.12 ― Risk control Loss heaviness Implementation of adequate TWS (as result of Tables C.8 to C.11) C.3 C.3.1 I Very highly recommended II Highly recommended III Recommended Not recommended Example n° – WIND TURBINE FARM (including its maintenance) Step 1: Identification of hazardous situations Identify one or several hazardous situations among the different possibilities of Table C.13 In case of a situation not covered in the table, select “Other situations” Table C.13 ― Identification of hazardous situations No Situation People in open areas without an appropriated lightning protected shelter available (according to EN 62305 series or other standards): outdoor activities, sports (football, golf, etc.), competitions, crowded events, farming, ranching or fishing activities, beaches, leisure areas Safeguard of sensitive goods: computer systems, electrical or electronic controls, emergency, alarm and safety systems Losses in operations and industrial processes Structures containing dangerous substances (inflammable, radioactive, toxic and explosive materials) Basic services whose continuity, quality or fast recovery shall be guaranteed (telecommunications, energy generation, transport and distribution, sanitary and emergency services) Infrastructures: ports, airports, railroads, roads, motorways, cableways Safety at workplace (activities that imply a risk at workplace in case of a thunderstorm) Zones that need civil or environmental protection: prevention of forest fires, etc Buildings, transport or facilities with their external areas open to the public 10 Other situations BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) C.3.2 - 36 - Step 2: Determination of type of loss For each selected situation of Table C.13, evaluate the different losses concerning people (Table C.14), goods (Table C.15), services (Table C.16) and environment (Table C.17) to determine the heaviness degree (I, II, III or 0) Table C.14 ― Loss concerning people Loss Heaviness degree Loss of human life I Serious injuries to people II Minor injuries to people III No injuries to people During maintenance operations or installation of wind turbines, workers can be very exposed to lightning threat Table C.15 ― Loss concerning goods Loss Heaviness degree Loss of valuable goods I Loss of common value goods II Minor losses of goods III No loss There is a risk of a direct strike to a wind turbine which can cause severe damages Table C.16 ― Loss concerning services Loss Heaviness degree Loss of valuable services I Loss of common services II Minor losses of services III No loss In the case of damage to critical components induced by lightning, the operation of the wind turbine will be stopped Table C.17 ― Loss concerning environment Loss Heaviness degree Environmental disaster I Damages to environment II Minor environmental damage III No loss BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) - 37 - If a blade is rotating when it is struck and destroyed by lightning, there is a risk of projecting debris in the nearby environment C.3.3 Step 3: Risk control A wind turbine is a basic service whose continuity, quality or fast recovery shall be guaranteed but also is a workplace with risk in case of a thunderstorm and both situations have to be analysed (see e.g also IEC 61400-24:2010, Clause 10) The risk to human life can be reduced by avoiding having workers on the wind turbine during thunderstorms The risk of damages and service losses due to a direct strike cannot be completely eliminated but it is possible to take preventive actions (disconnection of sensitive equipment, park wind turbine in a safe mode, etc.) Table C.18 ― Risk control Loss heaviness Implementation of adequate TWS (as result of Tables C.14 to C.17) I Very highly recommended II Highly recommended III Recommended Not recommended BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) - 38 - Annex D (informative) Catalogue of possible recommended preventive actions to be taken Preventive actions resulting in the knowledge of the lightning and/or storm electrification hazard strongly depend on the involved risk situation Then, these actions should be evaluated and applied in a detailed plan of action There is a great variety of situations and facilities that can need the implementation of a thunderstorm detection system Thus, the actions taken from an analysis resulting from the preventive information given by this system shall be specifically defined by the final user or by a designer specifically focused on this implementation For this purpose, what shall be taken into account is either the security and emergency plans or the possible technical modifications to be carried out in processes and systems It shall be kept in mind that decisions on preventive actions can involve actions (automatic, manual, acoustic, etc.) systemized into their own processes In order to give guidance on possible preventive actions, some example directives that could be implemented from the preventive information given by the detection system are listed These actions have a logical grading depending on the severity of the thunderstorm, which determines the activation level reached by the system: No alert level: – System working normally Level – Alert: – Primary preventive actions, consisting of informative notices as, for example, remote, visual or acoustic messages, etc – Auxiliary power systems can be activated Level – Emergency: – Secondary preventive actions – Auxiliary power systems activated – Critical and sensitive systems disconnected – Evacuation of exposed zones, to safe areas external metallic structures and proximities of lightning rod facilities Level – Maximum risk BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) - 39 - Table D.1 ― Possible preventive steps Phase of the thunderstorm I II III Balance Initial Growth Mature IV Dissipation Level of activation Steps to take No alert Alert Emergency Maximum risk Alert Possible preventive steps – System working normally – Warning of the people in charge of facilities and risky activities Primary preventive actions – Secondary preventive actions Possible activation of auxiliary power systems – Activation of feeding auxiliary power systems – Disconnection of sensitive systems – Evacuation of exposed zones, external metallic structures and proximities of lightning rod facilities – System ready for lightning impact – Warning of the people in charge of facilities and risky activities Primary preventive actions – Possible activation of auxiliary power systems BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) Detection system D.D - 40 - D.D N Detection system Multi-system detection system Single-system detection system Preventive information Control centre No alert level Primary preventive actions Secondary preventive actions Alert Level alarm Emergency Level alarm Maximum risk Level alarm Figure D.1 ― Possible preventive steps - 41 - BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) Annex E (informative) Example of TWS evaluation on a wind turbine site In this example, archived data of CG flashes are used to trigger the warnings and also to evaluate the efficacy of the alarms by checking what has really occurred at the wind turbine location Figure E.1 shows the CG lightning activity km around the wind turbine for a period of eight years Figure E.1 ― CG lightning activity around the wind turbine for a period of eight years (a total of 480 strokes were reported) The target is a circular area of km radius around the wind turbine The surrounding area (SA) is assumed to be a circle of km radius around the wind turbine (same area as displayed in Figure E.1) The MA consists also in a circular area around the wind turbine In this example the varying parameters are: – radius of the MA (10 km, 15 km and 20 km); – triggering criteria (number of flashes and time between flashes); – dwell time (DT) (10 min, 20 min, 30 min) All results are presented in Table E.1 BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) - 42 - Radius MA Number of flashes to trigger alarm Time between strokes for triggering Dwell Time (DT) in minutes Number of alarms (FA + EA) EA FTW FA FAR FTWR POD10 Table E.1 ― Results of TWS evaluation based on archived lightning date for an 8-year period (2000 to 2007), when some of the key parameters (size of MA, trigger parameters and dwell time) were varied 20 30 285 102 183 64 % 1% 89 % 15 30 220 102 118 54 % 2% 85 % 10 30 145 102 43 30 % 4% 73 % 20 30 571 102 469 82 % 1% 93 % 20 30 285 102 183 64 % 1% 89 % 20 30 229 102 127 55 % 2% 93 % 20 5 30 165 102 63 38 % 5% 88 % 20 2 30 264 102 162 61 % 2% 93 % 20 30 281 102 179 64 % 1% 89 % 20 20 321 102 219 68 % 1% 89 % 20 10 420 102 318 76 % 2% 86 % NOTE POD10 is the percentage of alarms delivered with a lead time of more than 10 - 43 - BS EN 50536:2011+A1:2012 EN 50536:2011+A1:2012 (E) Bibliography [1] Vladimir A Rakov, Martin A Uman Lightning: Physics and Effects Ed Cambridge University Press, 2003 [2] H.D Betz, U Schumann, P Laroche Lightning: principles, instruments and applications: review of modern lightning research Springer, 2008 [3] Thunderstorm threat! What can I do? (European COST Action P-18) [4] ACRP Report 8: Lightning-Warning Systems for Use by Airports ISBN: 978-0-309-11752-4, published by US Transportation Research Board in 2008 [5] IEC 61400-24:2010, Wind turbines ― Part 24: Lightning protection [6] CIGRE Brochure 376 “Cloud-to-Ground Lightning Parameters Derived from Lightning Location Systems – The Effects of System Performance”, Task Force C4.404, accepted for publication 2009 [7] R&A Rules Limited and The United States Golf Association, Rules of Golf, 31 Edition, 2008 st This page deliberately left blank This page deliberately left blank NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW British Standards Institution (BSI) BSI is the national body responsible for preparing British Standards and other standards-related publications, information and services BSI is incorporated by Royal Charter British Standards and other standardization products are published by BSI Standards Limited About us Revisions We bring together business, industry, government, consumers, innovators and others to shape their combined experience and expertise into standards -based solutions Our British Standards and other publications are updated by amendment or revision The knowledge embodied in our standards has been carefully assembled in a dependable format and refined through our open consultation process Organizations of all sizes and across all sectors choose standards to help them achieve their goals Information on standards We can provide you with the knowledge that your organization needs to succeed Find out more about British Standards by visiting our website at bsigroup.com/standards or contacting our Customer Services team or Knowledge Centre Buying standards You can buy and download PDF versions of BSI publications, including British and adopted European and international standards, through our website at bsigroup.com/shop, where hard copies can also be purchased If you need international and foreign standards from other Standards Development Organizations, hard copies can be ordered from our Customer Services team Subscriptions Our range of subscription services are designed to make using standards easier for you For further information on our subscription products go to bsigroup.com/subscriptions With British Standards Online (BSOL) you’ll have instant access to over 55,000 British and adopted European and international standards from your desktop It’s available 24/7 and is refreshed daily so you’ll always be up to date You can keep in touch with standards developments and receive substantial discounts on the purchase price of standards, both in single copy and subscription format, by becoming a BSI Subscribing Member PLUS is an updating service exclusive to BSI Subscribing Members You will automatically receive the latest hard copy of your standards when they’re revised or replaced To find out more about becoming a BSI Subscribing Member and the benefits of membership, please visit bsigroup.com/shop With a Multi-User Network Licence (MUNL) you are able to host standards publications on your intranet Licences can cover as few or as many users as you wish With updates supplied as soon as they’re available, you can be sure your documentation is current For further information, email bsmusales@bsigroup.com BSI Group Headquarters 389 Chiswick High Road London W4 4AL UK We continually improve the quality of our products and services to benefit your business If you find an inaccuracy or ambiguity within a British Standard or other BSI publication please inform the Knowledge Centre Copyright All the data, software and documentation set out in all British Standards and other BSI publications are the property of and copyrighted by BSI, or some person or entity that owns copyright in the information used (such as the international standardization bodies) and has formally licensed such information to BSI for commercial publication and use Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means – electronic, photocopying, recording or otherwise – without prior written permission from BSI Details and advice can be obtained from the Copyright & Licensing Department Useful Contacts: Customer Services Tel: +44 845 086 9001 Email (orders): orders@bsigroup.com Email (enquiries): cservices@bsigroup.com Subscriptions Tel: +44 845 086 9001 Email: subscriptions@bsigroup.com Knowledge Centre Tel: +44 20 8996 7004 Email: knowledgecentre@bsigroup.com Copyright & Licensing Tel: +44 20 8996 7070 Email: copyright@bsigroup.com