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【英文标准名称】:StandardTestMethodforHotSpotProtectionTestingofPhotovoltaicModules
【原文标准名称】:光电模块的热点保护试验的标准试验方法
【标准号】:ASTME2481-2008
【标准状态】:现行
【国别】:美国
【发布日期】:2008
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:E44.09
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:solar;energy;photovoltaics;modules;electricaltesting;hotspot;Electricaltests;Hotspots;Photovoltaic(PV)powersystems;Solarmaterials/applications;Testing
【摘要】:Thedesignofaphotovoltaicmoduleorsystemintendedtoprovidesafeconversionofthesun''sradiantenergyintousefulelectricitymusttakeintoconsiderationthepossibilityofpartialshadowingofthemodule(s)duringoperation.Thistestmethoddescribesaprocedureforverifyingthatthedesignandconstructionofthemoduleprovidesadequateprotectionagainstthepotentialharmfuleffectsofhotspotsduringnormalinstallationanduse.Thistestmethoddescribesaprocedurefordeterminingtheabilityofthemoduletoprovideprotectionfrominternaldefectswhichcouldcauselossofelectricalinsulationorcombustionhazards.Hot-spotheatingoccursinamodulewhenitsoperatingcurrentexceedsthereducedshort-circuitcurrent(Isc)ofashadowedorfaultycellorgroupofcells.Whensuchaconditionoccurs,theaffectedcellorgroupofcellsisforcedintoreversebiasandmustdissipatepower,whichcancauseoverheating.Note18212;Thecorrectuseofbypassdiodescanpreventhotspotdamagefromoccurring.Fig.1illustratesthehot-spoteffectinamoduleofaseriesstringofcells,oneofwhich,cellY,ispartiallyshadowed.TheamountofelectricalpowerdissipatedinYisequaltotheproductofthemodulecurrentandthereversevoltagedevelopedacrossY.Foranyirradiancelevel,whenthereversevoltageacrossYisequaltothevoltagegeneratedbytheremaining(s-1)cellsinthemodule,powerdissipationisatamaximumwhenthemoduleisshort-circuited.ThisisshowninFig.1bytheshadedrectangleconstructedattheintersectionofthereverseI-VcharacteristicofYwiththeimageoftheforwardI-Vcharacteristicofthe(s-1)cells.By-passdiodes,ifpresent,asshowninFig.2,beginconductingwhenaseries-connectedstringinamoduleisinreversebias,therebylimitingthepowerdissipationinthereduced-outputcell.Note28212;Ifthemoduledoesnotcontainbypassdiodes,checkthemanufacturerx2019;sinstructionstoseeifamaximumnumberofseriesmodulesisrecommendedbeforeinstallingbypassdiodes.Ifthemaximumnumberofmodulesrecommendedisgreaterthanone,thehotspottestshouldbepreformedwiththatnumberofmodulesinseries.Forconvenience,aconstantcurrentpowersupplymaybesubstitutedfortheadditionalmodulestomaintainthespecifiedcurrent.Thereversecharacteristicsofsolarcellscanvaryconsiderably.Cellscanhaveeitherhighshuntresistancewherethereverseperformanceisvoltage-limitedorhavelowshuntresistancewherethereverseperformanceiscurrent-limited.Eachofthesetypesofcellscansufferhotspotproblems,butindifferentways.Low-ShuntResistanceCells:Theworstcaseshadowingconditionsoccurwhenthewholecell(oralargefraction)isshadowed.Oftenlowshuntresistancecellsarethiswaybecauseoflocalizedshunts.Inthiscasehotspotheatingoccursbecausealargeamountofcurrentflowsinasmallarea.Becausethisisalocalizedphenomenon,thereisagreatdealofscatterinperformanceofthistypeofcell.Cellswiththelowestshuntresistancehaveahighlikelihoodofoperatingatexcessivelyhightemperatureswhenreversebiased.Becausetheheatingislocalized,hotspotfailuresoflowshuntresistancecellsoccurquickly.HighShuntResistanceCells:Theworstcaseshadowingco.........
【中国标准分类号】:F12
【国际标准分类号】:27_160
【页数】:5P.;A4
【正文语种】:英语


Product Code:SAE ARP5265
Title:Minimum Operational and Maintenance Responsibilities for Aircraft Tire Usage
Issuing Committee:A-5c Aircraft Tires Committee
Scope:This SAE Aerospace Recommended Practice (ARP) sets forth criteria for the installation, inflation, inspection, maintenance and removal of aircraft tires as well as criteria for the maintenance of the operating environment so as to achieve the purpose stated in 1.1. (Definitions of terms related to aircraft tires is found in 2.2.)