特高压主变充电导致直流周期性换相失败的原因（英文）

发布时间：2019-08-05 18:13

【摘要】：换相失败是直流输电系统逆变器最常见的故障之一,通常故障清除后直流系统可以恢复换相,周期性换相失败很少发生,过去国内从未出现过换相失败闭锁直流的情况。通过对林枫直流现场数据的深入分析,得出换相失败持续时间达到保护定值,保护正确动作;而励磁涌流引起枫泾站换流母线电压畸变、阀控VBE对已关断阀执行重触发以及换相失败恢复期间直流电流过冲等因素是导致林枫直流发生周期性换相失败的主要原因。在此基础上,基于电磁暂态程序建立了林枫直流输电研究模型,其中控制保护采用了与实际工程一致的详细模型,通过仿真研究提出了极控系统的改进措施:取消瞬时电流控制、优化换相失败预测和低压限流等功能,最后在林枫直流输电工程中进行了现场验证试验,试验结果验证了所提措施的有效性。
【图文】：

highvoltagemaintransformer500kVsideenergizingtest,bipolarperiodicalcommutationfailureinLinFengDCtransmissionsystemoccurred,after2.6sthreeprotectionsystemofLinFengbipolarreportedcommutationfailureandthenLinFengHVDCbipolarblocked.1.1OperatingStateBeforeFaultLinFengHVDCinvertersideislocatedatFengJingconverterstation,throughFengLian5107andFengTang5117double500kVACcircuitconnectstheLianTangstation,showedasFig.1,beforecommutationfailureoperatingstatusofAC/DCsystemisasfollows.图1交直流系统接线Fig.1ThewiringdiagramofAC/DCsystemLinfengHVDC:bipolaroperatingwithfullvoltage,thepowerdirection:TuanLin-FengJing,bipolartransmissionpowerwas1740MW.Liantangsubstation:1000kVsidebreakersincoldstandbystate;500kVside,5042,5043,5092,5093breakersincoldstandbystate,therestofthe500kVsidebreakerswererunning;110kVsidebreakerincoldstandbystate.LianTangstationNo.2andNo.4maintransformerswereincoldstandbystate,1000kVAnTangIandIIlineswereinmaintenancestate.1.2TheCommutationFailureProcessAccordingtoLinFengtransientfaultrecorder(TFR)andeventlists,beforeDCblocking,11timescommutationfailureoccurredineachpoleandtheintervaltimeofthecommutationfailurewas220~260ms.ThedurationfromthefirstcommutationfailuretoDCblockingwas2.6s,thensatisfiedcommutationfailureprotectionblockingconditions,DCprotectionsystemactedcorrectlyaccordingtosetlogic.

第38卷第10期电网技术2673LianTangstationclosed5043breakerandenergizedNo.21000kVextra-highvoltagemaintransformer.Thenperiodicalcommutationfailureoccurred,asshowninFig.2.Comment:inthefigureUacisconverterbusthree-phasevoltage,IVYisYYconvertertransformervalvesidethree-phasecurrent,IVDisYDconvertertransformerthree-phasecurrent,thefollowingissameasthese.图2林枫直流换相失败闭锁整体过程Fig.2ThewholeprocessofLinFengHVDCcommutationfailure1.3TheMechanismofPeriodicCommutationFailureCommutationfailureisoneofthemostcommonfaultsatHVDCsysteminverterside.DCsystemusuallycanrestoretothenormalconditionsafterfaultclearancesincethechanceislowforperiodiccommutationfailure.ThroughthedataanalysisofLinFengproject,itisconcludedthatthreefactors,includingmagnetizingsurgecurrentleadingtothebusvoltagedistortionatFengJingconverterstation,valvecontrolVBEretriggeringtheclosedvalveandDCovershootingduringcommutationfailurerecovery,arelikelytocauseLinFengHVDCperiodicalcommutationfailure.Amongthem,themagnetizingsurgecurrentcausingtheconverterbusvoltagedistortionismostcommoninformingcommutationfailure.Therefore,thisworkmainlyfocusonadetailedanalysisoftheothertwofactors.1)ValvecontrolVBERetriggerAnalysis.Fig.3showsthewaverecordofpole2图3现场极2换相失败录波Fig.3TheprojectcommutationfailureTFRofpole2commutationfailure.FromFig.3,thecommutationfailureoccursatbothYandDbridgessimultaneously.Inmeanwhile,thesetwocommutation
【作者单位】： 北京交通大学电气工程学院;中国电力科学研究院;中国普瑞科技有限公司;丹佛大学电子与计算机工程系;
【分类号】：TM721.1

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