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1、SECTIONFIFTEENELECTRICALSYSTEMSJamesM.BannonChiefElectricalEngineerSTVIncorporatedDouglassville,PennsylvaniaDesignoftheelectricalinstallationsinabuildingusedtobesimpleandstraight-forward.Suchinstallationsgenerallyincludedelectricalservicefromautilitycom-pany;powerdistributionwithinthebuildingfo
2、rreceptacles,airconditioning,andotherelectricalloads;lighting;andafewspecialtysystems,suchasfirealarmandtelephone.Therewere,ofcourse,somespecializedinstallationsforwhichthissim-pledescriptiondidnotapply,butsuchbuildingswereuncommon.Now,however,designofelectricalsystemshasbecomemorecomplexandsoph
3、isticated.Thisdevelopmenthasbeendrivenbyrapidadvancesintechnology,availabilityofcomputersandcomputerizedequipment,moreenlightenedlife-safetyandsecu-rityconcerns,andchangesinthephilosophicaloutlookofworkerstowardtheirworkplaceandtheirneedforacomfortableenvironment.Tomeettheseneeds,anewbuildingwi
4、lllikelyincludeinitselectricalinstallationanaccesscontrolsys-tem,intrusiondetectionsystem,anextensivecomputerdatanetwork,Internetac-cess,uninterruptiblepowersupply,andnumerousothersystemsnotcommonlyinstalledinthepast.Corollarytotheadventofthesenewbuildingsystemsistheneedforsuitablepowerqualityt
5、osupportthem.Thoughhighlysophisticatedandcapable,thesesystemscaneasilybedisruptedordamagedbypowersystemanom-aliessuchassags,surges,noise,andpoweroutages.Electricaldesignelementstoprotectagainstthesedisturbancesmustbeincludedandmustbedesignedtobeappropriatelysensitive,fast,androbust.Theintroduct
6、ionofelectricalcompetitioninsomestatesaddsfurthercomplexitytotheelectricalsystemdesignproblem.Notonlyhavethesesystemsbecomecommonbutthebasicelectricalsystemshaveundergonedrasticchanges.Advancesinelectrical-power-distributionmaterialsandmethods,whichhaveoccurredatanearlyuniformratesincetheturnof
7、thecentury,haveacceleratedrapidlyundertheinfluenceofcomputersandmicroproc-essorcontrols.Newlightsourcesgivedesignersaddedopportunitiestoimprovelightingandenergyefficiency.Microprocessor-basedfire-alarmsystemswithad-dressabledevicesof
