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1、兰州交通大学毕业设计(论文)牵引供电系统的高次谐波的仿真与分析摘 要电气化铁道作为公用电网的非线性负载,已成为引起电力系统谐波污染的主要谐波源之一。这主要是因为在电气化铁道上行驶的电力机车是单相的整流型负荷。由于功率大,分布广,而且三相不对称,在其运行过程中必然会产生大量的高次谐波,并将在接触网上激发起沿线分布的高次电压和电流谐波,它们对电气化铁道沿线的通信系统会造成严重的干扰。随着交直交动车组在电气化铁道中的大量采用,使得牵引供电系统中的谐波特性发生变化,除了含有低频带的3、5、7次等谐波外,在高频带还出现了大量
2、的高次谐波。尽管这些高频带谐波含有率不高,但其却大大增加了系统发生谐波谐振的可能性。当系统发生谐波谐振时,会形成较大的过电压和过电流,危害牵引变电所和电力机车等的绝缘设备,影响系统安全运行。本文对电力系统的谐波特性做了详细的理论研究和分析,重点阐述了牵引供电系统谐波的形成、谐波参数并对一些设备的谐波进行了分析,以便可以更加深刻的理解牵引供电系统的谐波分布,谐波形成和控制,维持牵引供电系统的稳定性和可靠性。最后,本文对牵引供电系统的高次谐波进行了仿真、分析,更加直观的展示了牵引供电系统的谐波特点及其分布,进一步加深理解
3、。关键词:高次谐波;牵引供电;谐波电流放大;MATLAB/Simulink-34-兰州交通大学毕业设计(论文)AbstractElectrifiedrailway,asthenonlinearloadofpublicelectricnet,hasbecomeoneofmainharmonicsourcescausingharmonicpollutioninthepowersystem,whichismainlybecausethatelectriclocomotiverunningontheelectrifiedra
4、ilwayissingle-phaserectifierload.Onaccountofitsgreatpower,widedistributionandthree—phaseasymmetric,itwillproduceagreatdealofhigh—orderharmonicsandonthecontactnetwillexcitehigh—ordervoltageandcurrentharmonicsdistributingalongtheline,whichwillinterfereseriously,w
5、iththecommunicationsystemalongtheelectrifiedrailway.WiththewideapplicationofAC—DC—ACmultipleunitsinelectricrailway,harmoniccharacteristicinthetractionPowersupplysystemhasbeenchanged.Notonlythelow—orderharmonies,forexample,third—order,fifth—orderandseventh—order
6、harmonicwereincludedinthissystem,butalsoalotofhigh—orderharmonicwerecontained.Althoughthecontentrateofthesehigh—orderharmonicsverylow,thepossibilityofharmonicresonanceinthesystemwillgreatlyincrease.Whenharmonicresonanceoccurredinthesystem,overvoltageandovercurr
7、entwillproduce,whichcanendangerequipmentinsulationoftractionsubstationandtrainandinfluencethesystemsafetyoperation.Inthispapertheharmoniccharacteristicofpowersystemtodoadetailedtheoreticalresearchandanalysis,expoundsthetractionpowersupplysystemharmonicformation
8、,andsomeequipmentharmonicparametersareanalyzed,sothattheycanmoreprofoundunderstandingofharmonicdistributionofthetractionpowersupplysystem,harmonicformationandcontrol,maintai