itu-t k.20-200307

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1、INTERNATIONALTELECOMMUNICATIONUNIONITU-TK.20TELECOMMUNICATIONSTANDARDIZATIONSECTOROFITU(07/2003)SERIESK:PROTECTIONAGAINSTINTERFERENCEResistibilityoftelecommunicationequipmentinstalledinatelecommunicationscentretoovervoltagesandovercurrentsITUTRecommenda

2、tionK.20ITU-TRecommendationK.20ResistibilityoftelecommunicationequipmentinstalledinatelecommunicationscentretoovervoltagesandovercurrentsSummaryThisRecommendationspecifiesresistibilityrequirementsandtestproceduresfortelecommunicationequipmentwhichisinsta

3、lledinaTelecommunicationCentre.OvervoltagesorovercurrentscoveredbythisRecommendationincludesurgesduetolightningonornearthelineplant,shortterminductionfromadjacenta.c.powerlinesorrailwaysystems,earthpotentialriseduetopowerfaults,directcontactsbetweentele

4、communicationlinesandpowerlinesandelectrostaticdischarges.Thesourcesforovervoltagesininternallines,betweenequipment/racks,aremainlyinductivecouplingcausedbylightningcurrentsbeingconductedinnearbylightningstrokesorlightningcurrentsbeingconductedinnearbyco

5、nductors.Majorchangescomparedwiththe2000versionofthisRecommendationinclude:•replacingthelongitudinaltestwithaporttoearthtest;•theintroductionofanexternalporttoporttest;•addingtheinternalportrequirementsfromITU-TRec.K.41.SourceITUTRecommendationK.20wasap

6、provedbyITUTStudyGroup 5(20012004)undertheITU-TRecommendationA.8procedureon29 July 2003.ITUTRec.K.20(07/2003)iiiFOREWORDTheInternationalTelecommunicationUnion(ITU)istheUnitedNationsspecializedagencyinthefieldoftelecommunications.TheITUTelecommuni

7、cationStandardizationSector(ITU-T)isapermanentorganofITU.ITU-Tisresponsibleforstudyingtechnical,operatingandtariffquestionsandissuingRecommendationsonthemwithaviewtostandardizingtelecommunicationsonaworldwidebasis.TheWorldTelecommunicationStandardization

8、Assembly(WTSA),whichmeetseveryfouryears,establishesthetopicsforstudybytheITUTstudygroupswhich,inturn,produceRecommendationsonthesetopics.TheapprovalofITU-TRecommendationsiscoveredbytheprocedurelaiddowninWTSAResolution 1.I