文档名：HVDC送端系统振荡引发受端换相失败的机理分析
摘要：高压直流输电系统送、受端存在电气耦合及两端的控制配合,因此,送端振荡可通过系统控制逻辑、电气量及控制量变化等影响受端系统的运行状态,增加了受端换相失败的风险.现有工作主要研究了送端大扰动引发受端换相失败的现象与机理,通过对标准直流系统进行小信号分析,发现直流系统中存在低频频段的固有振荡频率,一旦交流系统发生相近频段的振荡,将可能诱发直流系统共振.在此基础上,首先分析共振引起系统电气量以及控制量的波动对换相失败的影响,通过HVDC的准稳态方程分析共振后直流电流上升导致关断角下降,进而引发首次换相失败的机理;然后从两端的控制系统出发,研究逆变侧控制切换引发后续换相失败的机理;最后对CIGRE直流输电标准测试系统进行验证,并结合换相失败发生机理对换相失败的抑制策略进行了初步讨论.
Abstract：Strongelectricalandcontrolcouplingexistsbetweenthesendingandreceivingendsofahighvoltagedirectcurrent(HVDC)transmissionsystem.Therefore,disturbancesonthesendingendcanaffecttheoperationstateofthereceivingendsystemthroughchangesincontrollogic,electrical,orcontrolquantities,increasingtheriskofcommutationfailure(CF)onthereceivingend.ThephenomenonandmechanismofCFatthereceivingendcausedbylargedisturbancesatthesendingendhavebeenstudiedinexistingliterature.Thispaperidentifiestheexistenceofinherentoscillationmodeswithfrequenciessituatedinthelow-frequencyrangeinthesystem.WhenoscillationsofsimilarfrequenciesmanifestinthesendingACsystem,resonanceintheDCsystembecomesalikelyoutcome,causingCFinthereceivingend.Withouttimelycontrolofthisresonance,ittriggersswitchingofconstantcurrentcontrolandconstantextinctionanglecontrolattheinverterside.AnuncontrolledextinctionangleduringcontrolswitchingwilllikelycausesubsequentCFs,evenDCblocking.Therefore,discoveringthemechanismofsuchCFisimportanttocontributetotheoperationalsafetyandstabilityofHVDCtransmissionsystems.Firstly,thewholeprocessoftheCFcausedbythesendingendoscillationisanalyzedusingsimulationcurvesfromtheCIGREbenchmarkHVDCsystem.Accordingtothesimulationresults,fourdifferentstageshavebeenidentifiedafterthefirstdetectionofthesendingendoscillation.Secondly,theeigenvaluesoftheCIGREbenchmarkHVDCsystemarecalculatedusingasmall-signalstabilitymodel,andtheinherentoscillationmodesofthesystemaredetermined.Aspecialmode,inwhichthesendingendcurrentcontrollerplaysapivotalrole,isidentifiedbasedonparticipationfactorvalues.ThefrequencyofthespecialmodeoftheCIGREbenchmarksystemis1.2Hz,locatedinthelow-frequencyrange.Whenthesendingsystemencountersoscillationsofnearbyfrequencies,resonanceiseasilyinduced,causingcorruptioninthesendingendcontroller.Thequasi-steady-stateequationsareusedtoderivetheDCcurrentequationtoanalyzetheriseofDCcurrentafterresonance,resultinginafallintheextinctionangleandtriggeringthefirstCF.Then,thecontrolequationsareusedtoanalyzetheswitchingprocessofthesystemcontrollerandelucidatethemechanismthroughwhichcontrolswitchingleadstosubsequentCFs.Finally,thetheoreticalanalysisisvalidatedbysimulationsinPSCAD/EMTDC.Aseriesofoscillationswithdifferentfrequenciesaretested,i.e.,0.1Hz,0.6Hz,0.8Hz,1.2Hz,2.5Hz,7.6Hz,and66Hz.Theresultsshowthatoscillationsinthelow-frequencybandof0.1～2.5Hzcantriggerresonanceinthesystem,leadingtoCFatthereceivingend.Moreover,thefirstCFisobservedaround0.5safterinjectingthe1.2Hzoscillationintothesendingendsystem,fasterthanotheroscillationsfrom0.1Hzto2.5Hz,giventhat1.2Hzistheinherentoscillationfrequency.Additionally,oscillationsof7.6Hzand66HzdonotcauseCFs,althoughtheyarealsoinherentoscillationfrequencies.Theirparticipationfactorsindicatethatthesetwoinherentoscillationsareunrelatedtothesystemcontroller.Thefollowingconclusionscanbedrawnfromthepaper:(1)Fourstagesexistafterthesendingendoscillationoccurs,andCFswillhappenifthefrequencyisinaspecificrange.(2)TherootcauseofCFsarisingfromsendingendoscillationsistheresonancebetweentheseoscillationsandtheinherentoscillationmodesoftheHVDCsystem,inducingfluctuationsinelectricalandcontrolquantities.TheriseofDCcurrentinducesthefirstCF,andthecontrolswitchingleadstosubsequentCFs.(3)ThekeytopreventingCFscausedbysendingendoscillationsistotunethesystemparameterssothattheinherentoscillationmodehasastrongdampingratiointhecommonfrequencyband.
作者：郑乐 吴晶 徐衍会 孙英云 刘崇茹Author：ZhengLe WuJing XuYanhui SunYingyun LiuChongru
作者单位：华北电力大学电气与电子工程学院北京102206
刊名：电工技术学报
Journal：TransactionsofChinaElectrotechnicalSociety
年，卷(期)：2024, 39(9)
分类号：TM614
关键词：高压直流输电 送端振荡 受端换相失败 机理分析
Keywords：Highvoltagedirectcurrent sendingendoscillation commutationfailure mechanismanalysis
机标分类号：TM7S351.1TM614
在线出版日期：2024年5月13日
基金项目：国家重点研发计划HVDC送端系统振荡引发受端换相失败的机理分析[
期刊论文] 电工技术学报--2024, 39(9)郑乐 吴晶 徐衍会 孙英云 刘崇茹高压直流输电系统送、受端存在电气耦合及两端的控制配合,因此,送端振荡可通过系统控制逻辑、电气量及控制量变化等影响受端系统的运行状态,增加了受端换相失败的风险.现有工作主要研究了送端大扰动引发受端换相失败的现象...参考文献和引证文献
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