【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