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1、谐波和无功功率的产生(Generationofharmonicandreactivepower)Reactivepowerisalsocalledineffectivepowerandreactivepower.Takeasimpleexample:forexample,eatsteamedstuffedbun,itwasoriginallytoeat3toeat,thefirsttwobunsisequivalenttoreactivepower,andthethirdbaoziisactivepower.The
2、commoncompensationisreactivepowercompensationinparallelwiththepowercapacitorintheloop.Harmonics:periodicvoltageandcurrentsignalsofanyfrequencyotherthanthefundamentalfrequency(50Hzor60Hz)arecalledharmonics.Inpowersystem,thecommonlyusedmethodtosuppressharmonicsi
3、stoadoptparallelpassivefilteroractivefilterPassivefiltersgenerallyusecapacitorsandreactorsinseriestoformalowimpedanceloop,whichisusedtoabsorbharmonicsinthesystem,alsoknownaspassivefiltersAccordingtotheharmonicconditionofthesystem,theactivefilterproducesaharmon
4、icsourcewhichisthesameastheharmonicdirectionandthecurrentisequaltocounteracttheharmonicproducedinthesystem.Alsoknownasactivefilter1,whenthepowerisconnectedtoinductiveorcapacitiveload,duetoinductiveorcapacitiveloadisacomplex,expressionpowerisacomplex,theimagina
5、rypartiscalledreactivepower.Buttheperceptualloadvectoranglelag,capacitiveloadvectorangleadvance.Inordertomakethereactivepowerassmallaspossibleundertheconditionthattheapparentpowerremainsthesame,thenaddingcapacitiveloadstoreactivepoweriscalledcompensation.2,the
6、loadinalargenumberofutilitypowerelectronicdevices,thepowergridintheACinFourierseries,foundthatinadditiontocontainingthefundamentalcomponent,therearealotmorethanthefundamentalcomponentofhigherwaves,thesewavesarecalledharmonics.Therearemainlytwowaystoeliminateha
7、rmonics:usingdifferentconnectionmethodsoftransformertopreventharmonictransmission,ortofilterharmonicwithcapacitorfilter.Harmonicgeneration:nonlinearload,impactloadandotherlargeoperationfactorsofpowerusers,suchasarcfurnace,electriclocomotiverunningonthepowerqua
8、lity,theutilitygridharmonicinterference,producelargedisturbancevoltage,voltagefluctuationandflicker.Theharmofharmonic,harmonicpollutionwillhaveanimpactontheelectricpowerequipment,p