DesignandVerificationGuidanceforLightningProtectionSystemofWindTurbinesacc.tothenewRequirementsofIEC61400-24

18October2018XiWang1ChinaWindPower2018Content21.Introduction

2.MaindevelopmentinIEC61400-24,Ed.2

3.DNVGLCertificationServiceforLightningProtectionSystems4.Outlookandconclusions

WhatwearetalkingabouttodayLightningdamageisthesinglelargestcauseofunplanneddowntimeinwindturbinesandthemostcommoninsuranceclaimfiledbywindfarmowners.“ButmywindturbineDOhavealightningprotectionsystem!!”Why?3Source:Source:ChallengesoflightningprotectioninwindindustryLackingexperiencesandtechnicalunderstandingoflightningprotectionofWTGsinwindpowerindustry.Baddesignofthelightningprotectionsystem(LPS)ofblades,WTGSandwindfarms.Failuresinthemanufacturingandinstallation.PoormaintenanceoftheLPSon-site.Unclearrequirementsintheexistingstandards:Testingofthebladelightningprotectionsystemisnotmandatary.Testingprocedureisonly“informative”inIEC61400-24:2010,Ed.1andunclear.LackofaccreditedandacknowledgedtestinginstitutesforbladeLPSinChinauntil2017.VerylimitedpossibilitytoverifythedesignofbladeLPSbytesting.4DevelopmentinChina5Source:VAISALA.comWiththerapiddevelopmentofwindturbineinstallationinhighlightningdensityareas,e.g.inoffshoreandmountainousregions,lightningprotectionisbecomingmoreandmoreimportantforallstakeholdersinwindpowerindustry.Standardizedandverifiedlightningprotectionsysteminseries-producedwindturbinesisessentialandrequestedbythewindpowerindustry.IEC61400-24,Ed.2Developedby“IECTC88MT24LightningProtection”Lateststatus:88/641/CDVhaspassedthevotingin

April2018.FDISversionwillbedistributedforapprovalandvotingsoon.IEC61400-24,Ed.1wascompletelyrevised

tocoverthenewrequirements,recommendationsandbestpracticesforlightningprotectionofwindturbines.6Source:IECFDISofIEC61400-24,Ed.212sectionsasinIEC61400-24,Ed.1.MajorupdatesinSections6-12.17Annexes(A–Q)inEd.2,including4newAnnexes:AnnexN(informative)“GuidelinesforVerificationofBladeSimilarity”AnnexO(informative)“GuidelinesforValidationofNumericalAnalysis

Methods”AnnexP(informative)“TestingofRotatingComponents”AnnexQ(informative)“EarthingSystemsforWindFarms”AnnexD“TestSpecifications”isnownormative.Cleartestspecificationsandpass/failcriteria.7MainupdatesinFDISofIEC61400-24,Ed.2Section8-LightningprotectionofsubcomponentsVerificationmethodsofbladeLPS:a)HVandHCtests.(AnnexD)b)demonstrationofsimilarityoftheblade2withablade1previously

verifiedbytestingaccordingtoa).(AnnexN)c)usinganalysisorsimulationspreviouslyverifiedbycomparison

withtestresultsaccordingtoa).(AnnexO)

Testingaccordingtoa)ismandatory

fornewbladeprotectiondesigns.8Source:NTS.comVerificationmethodsofbearings:a)HCtest(AnnexP)b)demonstrationofsimilarityc)usinganalysisorsimulationsVerificationofbearingandbearingprotectiondesignconcepts9MainupdatesinFDISofIEC61400-24,Ed.2BearinglightningprotectionmethodPercentageofexpectedlightningcurrentinthepointofinstallation

Typeofverification

Bearingusedasmainlightningcurrentpath100%inbearingHCtestingofbearingBearingwithanaddtionallightnigcurrentbypasssytemCurrentsharingbetweenthebearinganditsbypasssystemHCtestingofbearingandprotectionsystemBypasssystemNegligibleHCtestofbypasssystemAnnexD(normative):TestSpecificationsHighvoltagetestsInitialleaderattachmenttest:90°,30°,10°Subsequentstrokeattachmenttest10MainupdatesinFDISofIEC61400-24,Ed.2Source:IECSource:IECHighcurrenttestsArcentrytest11MainupdatesinFDISofIEC61400-24,Ed.2Source:IEC12MainupdatesinFDISofIEC61400-24,Ed.2HighcurrenttestsConductedcurrenttestAnnexN(informative):GuidelinesforVerificationofBladeSimilarityNocleardefinitionof?similarity“inIEC61400-24,Ed.1.0

IEC61400-24,AnnexN?Blade1“hasbeensuccessfullyverifiedacc.toIEC61400-1,

Ed.1.0orEd.2.0bypassingallHVandHCtestsdescribedin

AnnexDComparisonofthenew?Blade2“with?Blade1“acc.to

TableN.1inrespectofdesignandmaterialofbladeandbladeLPS.ThisapproachisnowappliedtoDNVGLcertificationprojects.13MainupdatesinFDISofIEC61400-24,Ed.2AnnexP(informative)-TestingofRotatingComponentsThefinalevaluationofbearingtestingshouldincludeanevaluationoftheremainingoperationallifetimeofthebearingaftertesting.14MainupdatesinFDISofIEC61400-24,Ed.2DNVGLCertificationServiceforLightningProtectionSystemsComponentCertificationfor:LPSofrotorbladesSPDsLightningmeasurementandmonitoringsystemsLaboratoryApprovalTechnologyQualificationfornon-standardandinnovativesolutions,

e.g.de/anti-icingsystemofrotorblades.RetrofitsolutionofexistingLPSdesign1516OutlookandconclusionsStandardizedandverifiedlightningprotectionsysteminseries-producedwindturbinesisessentialandrequestedbythewindpowerindustry.IEC61400-24,Ed.2willcoverthenewrequirements,recommendationsandbestpracticesforlightningprotectionofwindturbinesbasedonthelon