PromotingResearch,ApplicationsandEducationonLightning
LightningProtectionofBuildings:GuidancetoMSIEC62305andUpdatesfrom
WorkingGroup/ResearchInstitute
ProfessorMohdZainalAbidinAbKadir,PhDPEngCEngCELPUPMChair,IECTC81:LightningProtection(NationalMirrorComm)ImmediatePastChair,IEEEPESMalaysiaChapterChair,MNC-CIGREC4:SystemTechnicalPerformanceWGCommittee:IEEE1410;CIGREC4.23,C4.27
- seen at few hundred meters - less than 1 m to over 1 km
Flashover
Return stroke current
Channel Base
Current Striking
Distance
Coupling
Electromagnetic Field
P
z
2
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THECIRCULAR
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THEGUIDEBOOK
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MSIEC62305(2007)
• MSIEC62305-1:2007-Generalprinciples
• MSIEC62305-2:2007-Riskmanagement
• MSIEC62305-3:2007-Physicaldamagetostructuresandlife hazard
• MSIEC62305-4:2007-Electricalandelectronicsystemswithin structures
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§ OriginsofLightningProtectionSystems§ GeneralPrinciple§ RiskAssessment§ LightningProtectionSystem§ SurgeProtection§ InspectionandMaintenanceofLPS§ UpdatesfromWG/ResearchInst.§ ConcludingRemarks
PRESENTATIONOUTLINES
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ORIGINSOFLIGHTNINGPROTECTION
PromotingResearch,ApplicationsandEducationonLightning
- Earliestliteratureavailable:1752(BenjaminFranklin)- He consequently published the first instruction for lightningprotection:
“Themethodisthis:Provideasmallironrod(maybemadeoftherodironusedbytheNailers)butofsuchlength,thatoneendbeingthreeorfourfeetinthemoistground,theothermaybesixoreightfeetabovethetallestpartofthebuilding.Totheupperendoftherod,fastenaboutafootofbrasswire,thesizeofacommonknittingneedle,sharpenedtoafinepoint;therodmaybesecuredtothehousebyafewsmallstaples.Ifthehousebelong,theremaybearodandpointeachendandamiddlingwirealongtheridgefromoneto theother.Ahousethus furnishedwillnotbedamagedbylightning, itbeingattractedbythepointsandpassingthroughthemetalintothegroundwithouthurtinganything..”[1][1] B Franklin. “How to secure houses from lightning”, Poor Richards’s Almanac,reproduced in Benjamin Franklin’s Experiments, edited by I. Bernard Cohen,HarvardUniversityPress,1941.
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Earlyfieldtrialsandinvestigationoffailures:BoardHouseatPurfleet,Essex,England
- Reported by Nickson [2] where lightning protection was installed and struck shortly thereafter. Yet the lightning rod was not struck. - Investigation revealed another metallic object was struck and lightning conducted to ground. - This incident caused the first reconsideration of lightning protection technology and it’s techniques.
[2] E Nickson (Store-keeper at Purfleet), “XV. Sundry papers relative to an accident from lightning at Purfleet, May 15, 1777. Report to the Secretary of the Royal Society”. Phil. Trans., Royal Soc., LXVIII, for 1778, Part. 1, pp 232-235.
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KnowledgegainedfromPurfleetincident
- Lightning-damaged corner of the Board House was not adequately protected by the closest lightning rod, installed above the centre of the 44-foot (13.5m) high building with a tip-height of 27 feet (~8m) above and horizontal distance of 37 feet (~11m) from the lightning strike point [3]. - This incident drove the first recommendations for lightning protection systems concerning bonding of incidental metal and the first consideration concerning the effective range of strike terminations. It also set off the blunt vs. pointed air terminal arguments.
[3] RH Golde, “Lightning”, Vol. 2, Academic Press London, 1977, pp 546 provides a pictorial description of Purfleet..
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11
GENERALPRINCIPLE
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Thepropagationofadownwardsteppedleaderandtheinterceptionwithatreeonearth
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The short stroke current (impulse) asspecifiedinMSIEC62305-1-2007
The long stroke current (continuingc u r r e n t ) s p e c i fi ed i n MS I E C62305-1:2007. Tlong can vary between 2msto1000ms.
LightningCurrent
Comparisonofreturn-strokepeakcurrents(thelargestpeak,inkA)forfirststrokesinnegativedownwardlightning
References Location Sample size
Percent exceeding tabulated value σlogI (base
10)
Remarks
95% 50% 5%
Berger et al. (1975) Switzerland 101 14 30 (~30) 80 0.26 Direct measurements on 70-m towers
Anderson and Eriksson (1980)
Switzerland
80 14 31 69 0.21 Direct measurements on 70-m towers
Dellera et al. (1985) Italy 42 - 33 - 0.25 Direct measurements on 40-m towers
Geldenhuys et al. (1989)
South Africa 29 7* 33 (43) 162* 0.42 Direct measurements on a 60-m mast
Takami and Okabe (2007)
Japan 120 10 29** 85 0.28** Direct measurements on 40- to 140-m transmission-line towers
Visacro et al. (2011) Brazil 38 21 45 94 0.20 Direct measurements on a 60-m mast
Anderson and Eriksson (1980)
Switzerland (N=125), Australia (N=18), Czechoslovakia
(N=123), Poland (N=3), South Africa (N=11), Sweden (N=14),
and USA (N=44)
338 9*
30 (34) 101*
0.32 Combined direct and indirect (magnetic link) measurements
CIGRE Report 63 (1991)
Switzerland (N=125), Australia (N=18), Czechoslovakia
(N=123), Poland (N=3), South Africa (N=81), Sweden (N=14),
and USA (N=44)
408 - 31 (33) - 0.21 Same as Anderson and Eriksson’s (1980) sample plus 70 additional measurements from South Africa
The95%,50%,and5%valuesaredeterminedusingthelognormalapproximationtotheactualdata,with50%valuesintheparenthesesbeingbasedontheactualdata.σlogIisthestandarddeviationofthelogarithm(base10)ofpeakcurrentinkA.*AsreportedbyTakamiandOkabe(2007).**26kAand0.32aftercompensationforthe9-kAlowermeasurementlimit.
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MSIEC62305-2:2007page87,AnnexA,specifyapproximaterelationshipofthelightningdensityNgwithkerauniclevelthunderdaysTdfortemperatelandonly.Ng=0.1Td
whereNgisthegroundflashdensityinflashesperkm2peryearTdisthenumberofdayswiththunderperyear
LightningSeverity
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3-5% Direct Strike 1-2% Contact Injury 30-35% Side Splash / Flash 50-55% Ground Current 10-15% Upward Streamer
InjuryMechanisms
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LightningInjuries/Fatalities
Basedonthenoofvictims*
*AsofSept2015
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total2008 3 0 0 3 3 2 0 0 0 0 9 0 202009 0 0 0 0 13 6 0 0 0 8 0 5 322010 0 0 0 2 0 0 0 0 9 2 0 0 132011 1 2 1 0 0 3 3 12 2 1 4 1 302012 0 5 1 56 7 1 5 5 1 0 5 0 862013 0 12 1 2 0 0 2 1 2 0 0 0 202014 0 0 4 1 2 0 0 0 0 2 2 0 112015 0 0 0 12 4 0 1 1 5 0 0 0 23Total 4 19 7 76 29 12 11 19 19 13 20 6 235
NO PLACE OUTSIDE is safe when
thunderstorms are in the area
LightningSafety
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www.celp.upm.edu.my
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LIGHTNINGRISKASSESSMENT
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Ø To reduce the potential for damage effectively andeconomically.
Ø The general steps in risk assessment analysis are described inbelow:v Damageandlossesv Riskanditscomponentsv Riskassessmentv Riskmanagement
PromotingResearch,ApplicationsandEducationonLightning
AdoptedfromMSIEC62305-2:2007Section5.5
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LIGHTNINGPROTECTIONSYSTEM
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BasicConcept
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R
α H
Protective angle
Rolling sphere
Mesh
AirTerminationSystem
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ProtectiveAngleMethod
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MeshMethod
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RollingSphereMethod
Ø Rollingspheremethodissuitableforanytypeofbuilding,especiallyhighrisebuildingwithcomplexplan.
Ø ShouldconsideranimaginarysphereofradiusRwherethevalueofRdependsonthelevelofprotection
PromotingResearch,ApplicationsandEducationonLightning
RollingSphereMethod
h<60m
h>60m
Anobjectwithisolatedverticalrods;minheightoftheverticalrod=h+p
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AirTermination:MaterialsandDimension
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§ Thereareseveralavailablematerialsthatcanbeusedintheconstructionofairterminationsystem,aslongastheyfulfillsomecriteriasuchas;
§ Non-corrosive(materialstobecombined)§ Compliancewithmincross-sectionaldimensions§ Compliancewithminthickness
PromotingResearch,ApplicationsandEducationonLightning
Material Hot-dip GI
Aluminum Copper SS Mild Steel
Hot-dip GI ✔ Possible
✖ Possible Possible
Aluminum Possible ✔ ✖ Possible
✖ Copper
✖ ✖ ✔ Possible ✖
SS Possible Possible Possible ✔ Possible
Mild steel Possible ✖ ✖ Possible
✔
Suitabilityofmaterialsforinterconnection
MaterialThickness(mm)
Ifpuncturingshouldbeavoided
Thickness(mm)Ifpuncturingis
acceptableGIandStainlessSteel 4 0.5
Aluminum 7 0.7Copper 5 0.5Zink Notrecommended 0.7
Titanium 4 0.5
PromotingResearch,ApplicationsandEducationonLightning
Minimumthicknessofbuildingcomponentsthatcanbeusedasapartof the air termination system. Note that these specifications areindependentoftheLevelofProtection
DownConductor
PromotingResearch,ApplicationsandEducationonLightning
§ Shouldconsider:
§ Minnoofdownconductor(i.e.2)§ Position§ Separation§ Bending§ Safetyclearence(mandatorytocoverthefirst1.5mlength
abovethegroundwithaninsulationmaterialtoavoidtouchpotential)
§ Accessibilityforinspection§ Naturalcomponents(Section3.5,MSIEC62305-3:2007)
KEY: (1) Air termination rod; (2) Horizontal air termination conductor; (3) Down-conductor; (4) T-type joint; (5) Cross type joint; (6) Connection to steel reinforcement rods; (7) Test joints; (8) Type B earthing arrangement, ring earth electrode; (9) Flat roof with roof fixtures; (10) T-type joint-Corrosion resistant
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EarthTerminationSystem
§ todispersedthelightningcurrentintothemassoftheearth.
§ toreduceanypotentiallydangerousovervoltages.
§ Ingeneral,anearthingresistancebelow10Ω,measuredatlowfrequency,isrecommended.
§ From the view point of lightning protection, a single integrated earth-termination system ispreferableand is suitable forallpurposes, suchaslightningprotection,powersystemandtelecommunicationsystems.
§ Earth termination system shall be bonded to achieve a lightningequipotentialbondingtominimizetheaffectoflightningsideflashingandsteppotentialhazard.
PromotingResearch,ApplicationsandEducationonLightning
TypeA
Horizontal
Vertical
50cm
Electrodesthatareconnecteddirectlyattheendofthedownconductor
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Figure 28: The minimum length of Type A electrodes (Adopted from MS IEC 62305-3:2007).
TheminimumlengthofTypeAelectrode(AdoptedfromMSIEC62305-3:2007).
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TypeB
§ TypeBarrangement compriseseither a ring conductor installedexternaltothestructuretobeprotected,incontactwiththesoilforatleast80%ofitstotallength,orafoundationearthelectrode.Suchearthelectrodesmayalsobemeshed.
§ Refer to MS IEC 62305-3:2007, Section 5.4.2.2 for determining thespecificationsofTypeBarrangement.
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Generalguidancefortheselectionofmaterialforearthingsystem(AdoptedfromMSIEC62305-3:2007)
Confi
guratio
nan
dminim
umdim
ension
sofearthelectro
des
(MSIEC62
305-3:20
07pag
e55
)
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BackfillMaterial
§ Commonpracticetoreducetheearthresistance.
§ Fewsuchmaterialsarebentoniteandbentonite-basedcompounds,cokebreeze,graphiteandlime.
§ Fordetailsoftheselectionandusageofperformanceenhancementmaterials of earthing systems, refer IEC 62561-7 (2011): Lightningprotection system components (LPSC) - Part 7: Requirements forearthingenhancingcompounds.
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LightningProtectionMeasures(LPM)
ZonalConceptMSIEC62305-3:2007,pp.25
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BasicLPM
a.Earthingandbonding
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Integration of electronicsystems into the bondingnetwork
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C o m b i n a t i o n o fintegrationmethod-Forcomplexsystem
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Minimumcross–sectionalareaforbondingcomponents
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b.Magneticshieldingandlinerouting
§ Arisefromlightningflashesdirecttoornearbythestructure.§ Spatial shieldsmaybe grid-like, or continuousmetal shields, or comprise
thenaturalcomponentsofthestructureitself.§ Shielding of internal lines: using metallic shielded cables, metallic cable
ductandmetallicenclosureofequipmentwillminimized internal inducedsurges.
§ Routinginternallines:tominimizeinductionloopsandreducethecreationof internal surges to the structure. The loop area can be minimized byrouting the cables close to natural components of the structure, whichhavebeenearthedandbyroutingelectricalandsignallinestogether.
§ Shieldingofexternallines:toreducesurgesfrombeingconductedontotheinternalsystems.·
§ Materials and dimensions of magnetic shields shall comply with therequirementsofMSIEC62305-3:2007
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c.CoordinatedSPDprotection§ To limits the effect of internal and external surges for both power and
signallines.
§ To share the energy between them according to their energy absorbingcapability.
§ ThecharacteristicsoftheindividualSPDsaspublishedbythemanufacturerneedtobeconsidered.
§ Theprimarylightningthreatisgivenbythethreelightningcomponents:
o Thefirstshortstrokeo Thesubsequentshortstrokeso Thelongstroke
§ The energy coordination is needed to avoid SPDs within a system frombeingoverstressed.
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SURGEPROTECTION
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ForoptimumperformanceofSPDs;ü Wiringsystem, starting fromthemainpanel, is according to the
nationalcodesofpractice.
ü Electrical safety devices such as earth fault tripping devices(RCDs, RCCBs or ELCBs), over current tripping devices (MCBs,MCCBs or thermal fuses) and voltage stabilizing devices areproperlyinstalledandareingoodcondition
ü Electrical system has a single earthing point (close to the mainpanel)withlowearthresistancewhenmeasuredatlowfrequencyattheearthpit,
ü Power feeds to outdoor systems are confined into dedicateddistributionboards,
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For a productive and cost effective surge protection scheme thefollowingstepsshouldbetaken:ØSystemanalysisandriskassessmentØStrategiclocationselectionforprotectivedevicesØSelectionofappropriatelycoordinatedprotectivedevicesØProperinstallationandcommissioningØRegularmaintenanceandreplacementoffaultydevicesFor installation,abuilding isdivided intoseveralzonesofprotection(referMSIEC62305-4:2007Section4)
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SelectionofSPDsforpowersystems
§ Wheretoinstall:mainpanel,subpanels,plugetc.§ ImpulseCurrenthandingCapacity,Iimp
§ Letthroughvoltage(Voltageprotectionlevel),Up
§ Responsetime§ MaximumContinuousOperatingVoltage(MCOV)SelectionofSPDsoncommunicationanddatalines§ Systemoperatingcurrentandvoltage§ Bandwidthandinsertionlosses§ Noofpins(lines)&cabletype§ Plugtype
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INSPECTIONANDMAINTENANCEOFLPS
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Toascertainthat;Ø TheLPSconformstothedesignbasedonthisstandard
Ø All components of the LPS are in good condition andcapable of performing their designed functions, and thatthereisnocorrosion
Ø Any recently added services or constructions areincorporatedintotheLPS.
Objectives
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Inspectionsshouldbemadeasfollows:o During the construction of the structure, in order to check the
embeddedelectrodes
o AftertheinstallationoftheLPS
o Periodically at such intervals as determined with regard to thenatureofthestructuretobeprotected,i.e.corrosionproblemsandtheclassofLPS
o Afteralterationsorrepairs,orwhenitisknownthatthestructurehasbeenstruckbylightning.
Complete guidelines of inspection and maintenance of LPS is given in MS IEC 62305-3:2007 Section 7 and Section E7
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Maintenance
Regular Inspection is among the fundamental conditions forreliable maintenance of an LPS. The property owner shall beinformedofallobservedfaultsandtheyshallberepairedwithoutdelay.Forfurtherdetailsofmaintenance,referSec7inMSIEC62305-3.
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UPDATESFROMWG/RESEARCHINST.
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§ LPSWG: Newly approved TC 81 (NationalMirror Committee) byISCECommitteeinJune2015
§ Lightning Safety: Recent Strategic Meeting in Lusaka, Zambia,organizedbyNAMS&T.Fromthismeeting;o A Resolution for Declaration of the International Lightning
Safety Day on 28th June every year, which was unanimouslyadopted by the participants of the International Symposiumand Strategic Meeting on Lightning Protection, has beensubmittedtoUNESCO.
§ Technical Brochure: TB 549-2013: Lightning Parameters forEngineeringApplications,byWGC4.407
§ Seminar:School’sEnvironmentalSafety,organizedbyMinistryofEducationandattendedby120teachersinBesut,Terengganu.
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CONCLUDINGREMARKS
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² MSIEC62305seriesprovidecomprehensiveguidelinesonthedesignandinstallationofLPSforbuildings.
² The developed book is NOT a replacement to the existingstandards MS IEC 62305 but it is an easy guide to thosedocuments.
² ItisalsoNOTjustasummaryofthosestandards,butprovideeasy access andquick reference to thedetaileddocuments,withsomeclearandusefulillustrations.
² Updates fromWG/ Research Inst. are useful and crucial forknowledgesharing,activityplanningandresearchprogressinlightning-relatedareas.
• General Public: To understand the basic principles of lightningprotection
• Engineers: To make sure that they design, select, install,superviseandenforceLPSwherethequalityandsafetyisinlinewithMSIEC62305(2007)
• LPProviders:TounderstandtheacceptabilityandqualityoftheirsystemsareinlinewithMSIEC62305(2007)
• LPSeekers:Tounderstandwhethertheygetthecorrectsystem
• Management:Tounderstandwhethertheyapprovedthecorrectsystem
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OnGuidebook
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ContactUs:CentreforElectromagneticandLightningProtectionResearch(CELP)FacultyofEngineering,[email protected]