發(fā)布時間：2019-08-05 18:13

【摘要】：換相失敗是直流輸電系統(tǒng)逆變器最常見的故障之一,通常故障清除后直流系統(tǒng)可以恢復換相,周期性換相失敗很少發(fā)生,過去國內從未出現過換相失敗閉鎖直流的情況。通過對林楓直流現場數據的深入分析,得出換相失敗持續(xù)時間達到保護定值,保護正確動作;而勵磁涌流引起楓涇站換流母線電壓畸變、閥控VBE對已關斷閥執(zhí)行重觸發(fā)以及換相失敗恢復期間直流電流過沖等因素是導致林楓直流發(fā)生周期性換相失敗的主要原因。在此基礎上,基于電磁暫態(tài)程序建立了林楓直流輸電研究模型,其中控制保護采用了與實際工程一致的詳細模型,通過仿真研究提出了極控系統(tǒng)的改進措施:取消瞬時電流控制、優(yōu)化換相失敗預測和低壓限流等功能,最后在林楓直流輸電工程中進行了現場驗證試驗,試驗結果驗證了所提措施的有效性。
【圖文】：

highvoltagemaintransformer500kVsideenergizingtest,bipolarperiodicalcommutationfailureinLinFengDCtransmissionsystemoccurred,after2.6sthreeprotectionsystemofLinFengbipolarreportedcommutationfailureandthenLinFengHVDCbipolarblocked.1.1OperatingStateBeforeFaultLinFengHVDCinvertersideislocatedatFengJingconverterstation,throughFengLian5107andFengTang5117double500kVACcircuitconnectstheLianTangstation,showedasFig.1,beforecommutationfailureoperatingstatusofAC/DCsystemisasfollows.圖1交直流系統(tǒng)接線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期電網技術2673LianTangstationclosed5043breakerandenergizedNo.21000kVextra-highvoltagemaintransformer.Thenperiodicalcommutationfailureoccurred,asshowninFig.2.Comment:inthefigureUacisconverterbusthree-phasevoltage,IVYisYYconvertertransformervalvesidethree-phasecurrent,IVDisYDconvertertransformerthree-phasecurrent,thefollowingissameasthese.圖2林楓直流換相失敗閉鎖整體過程Fig.2ThewholeprocessofLinFengHVDCcommutationfailure1.3TheMechanismofPeriodicCommutationFailureCommutationfailureisoneofthemostcommonfaultsatHVDCsysteminverterside.DCsystemusuallycanrestoretothenormalconditionsafterfaultclearancesincethechanceislowforperiodiccommutationfailure.ThroughthedataanalysisofLinFengproject,itisconcludedthatthreefactors,includingmagnetizingsurgecurrentleadingtothebusvoltagedistortionatFengJingconverterstation,valvecontrolVBEretriggeringtheclosedvalveandDCovershootingduringcommutationfailurerecovery,arelikelytocauseLinFengHVDCperiodicalcommutationfailure.Amongthem,themagnetizingsurgecurrentcausingtheconverterbusvoltagedistortionismostcommoninformingcommutationfailure.Therefore,thisworkmainlyfocusonadetailedanalysisoftheothertwofactors.1)ValvecontrolVBERetriggerAnalysis.Fig.3showsthewaverecordofpole2圖3現場極2換相失敗錄波Fig.3TheprojectcommutationfailureTFRofpole2commutationfailure.FromFig.3,thecommutationfailureoccursatbothYandDbridgessimultaneously.Inmeanwhile,thesetwocommutation
【作者單位】： 北京交通大學電氣工程學院;中國電力科學研究院;中國普瑞科技有限公司;丹佛大學電子與計算機工程系;
【分類號】：TM721.1

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