文档名：混合多端直流输电系统限流控制策略配合及限流参数全局优化
摘要：混合多端直流输电系统短路电流水平超标对其安全稳定运行造成极大威胁.现有通过控制策略限流的方法多以本站出口侧最严重的极间故障展开分析,忽略了过渡电阻对两侧系统的耦合作用,且控制参数的不合理配置会降低故障点非零电位大小,进而加剧线路过电流现象.为此,首先,阐述了混合多端直流输电系统常见控制限流策略;其次,对换流站自身的控制特性及站间交互作用对故障电流的影响机理展开分析,提出计及过渡电阻耦合作用下故障电流的计算方法;然后,在此基础上,综合考虑控制参数灵敏性、限流效果等约束,建立控制参数全局优化数学模型,通过层次分析法得到控制参数的最优解;最后,基于PSCAD/EMTDC对传统限流特性及全局优化下的限流特性进行对比分析.结果表明,所提方法能在提高限流效果及满足参数灵敏性的基础上更好地适应经过渡电阻故障的情况,降低故障时电流上升率和电流峰值,协助降低两侧换流站因增流现象加剧线路过电流情况而闭锁的概率.
Abstract：HybridDCtransmissiontechnologyeffectivelyimprovestheinterconnectionbetweenACsystemsandnewenergyresources,andbecomesanewwayforlarge-scalewindpower,photovoltaicandothernewenergytoconnecttothepowergrid.However,onceashort-circuitfaultoccursintheDCline,thestableoperationofthesystemwillbeseriouslythreatenedbytherapidgrowthofDCfaultcurrents.Therefore,itisnecessarytotakecorrespondingcurrent-limitingmeasurestosuppresstherapidgrowthoffaultcurrents.Theselectionofcurrent-limitingcontrolparametersoftheexistingsystemismostlyorientedtothefaultcurrentcharacteristicsofthelocalconverterstation,sothattheovercurrentofthelocalsystemmaybeaggravatedbythecouplingeffectofthefaultresistanceaftertheactivecurrent-limitingisadoptedinthefar-endsystem.Therefore,acalculationmethodofthefaultcurrentofthehybridmulti-terminalDCtransmissionlineconsideringthecouplingeffectofthefaultresistanceisproposedafterinvestigatingthephenomenonandreasonsoftheexacerbatedovercurrentalonglocalstationlinesafterthestartofthecurrent-limitinglinkatthefar-endconverterstation,andthecurrent-limitingparametersaregloballyoptimizedtobetteradapttoshortcircuitsthroughfaultresistance.Intermsofthecalculationoffaultcurrent,thecharacteristicsofvoltagedependentcurrentorderlimiter(VDCOL)strategyforLCCrectifierstationsandactivecurrent-limitingstrategyforMMCinverterstationsarefullyconsidered,andtheinfluencemechanismoftheinteractionofcontrolcharacteristicsbetweenconverterstationsonlinefaultcurrentisclarified.TheinfluenceofdifferentcontrolparametersofLCCandMMConthesystem'scurrent-limitingcapabilityisanalyzedbysensitivityindex.Accordingtotheresponsecharacteristicsofthecontrolsystemandthetimingcoordinationlogicbetweenthecontrolsystemsoftheconverterstation,athree-stagefaultcurrenttransientcharacteristicdivisionprinciplesuitableforconsideringthecurrent-limitingcontrollinkisproposed,andashort-circuitcurrentcomplexfrequencydomainsegmentationmodelcoveringthewholeprocessisestablished.Thencurrentincrementofthelocalstationlineafterthepickupofthecurrent-limitingcontrolinthefar-endstationisobtainedbytheinverseLaplacetransform,whichhelpsimprovetheaccuracyofjudgingthefaultcurrentdevelopmenttrend.Intermsofglobaloptimizationofcurrent-limitingparameters,basedontheanalytichierarchyprocess(AHP),comprehensiveindicesincludinglineovercurrentmultiple,overcurrenttimeanddropdegreeofACbusvoltageareestablished.Theglobal-optimizationmodelofcontrolparametersisconstructedtoavoidthepossibilityofACsidevoltagedropunderasinglefactor.Finally,basedonPSCAD/EMTDC,thecurrent-limitingcharacteristicsundertraditionalmethodsandtheproposedglobaloptimizationschemearecomparedandanalyzed.Simulationresultsshowthat,theVDCOLlinkoftheLCCconverterstationandtheactivecurrent-limitinglinkoftheMMCconverterstationcaneffectivelysuppresstheDCfaultcurrent,buttheVDCOLlinkneedstoadjustthefiringangleindirectlythroughtheconstantcurrentcontroller,whichhaslimitedabilitytorestrictthefaultcurrentwithinthetransienttimescaleofthefault.Theactivecurrent-limitinglinkcaneffectivelyreducethepeakvalueofthefaultcurrentbycorrectingtheDCvoltage,whilethereisariskofcurrentincreaseattheconverterstationduetothecouplingeffectofthefaultresistance.Theproposedmethodcanbetteradapttoshortcircuitsthroughfaultresistanceonthebasisofimprovingthecurrent-limitingeffectandsatisfyingthesensitivityoftheparameters,canreducethecurrentriserateandcurrentpeakvalueduringthefault,andhelptoreducetheprobabilityoftheconverterblockingduetothecurrentincrementwhichaggravatesthelineovercurrent.Inaddition,theproposedfaultcurrentcalculationmethodcanbeusedtoanalyzetheinfluenceafterthepickupofthecurrent-limitingcontrol,providingareferenceforthethresholdsettingoflineprotectionandtheselectionofcircuitbreakers.
作者：李杭泽 戴志辉 韩哲宇 奚潇睿 牛宝仪 杨明玉Author：LiHangze DaiZhihui HanZheyu XiXiaorui NiuBaoyi YangMingyu
作者单位：新能源电力系统全国重点实验室(华北电力大学)保定071003
刊名：电工技术学报 ISTICEIPKU
Journal：TransactionsofChinaElectrotechnicalSociety
年，卷(期)：2024, 39(11)
分类号：TM713
关键词：主动限流控制 低压限流 混合多端直流输电 过渡电阻 参数优化
Keywords：Activecurrent-limitingcontrol voltagedependentcurrentorderlimiter hybridmulti-terminalDCtransmission faultresistance parameteroptimization
机标分类号：TM773TM46TM561
在线出版日期：2024年6月18日
基金项目：国家自然科学基金混合多端直流输电系统限流控制策略配合及限流参数全局优化[
期刊论文] 电工技术学报--2024, 39(11)李杭泽 戴志辉 韩哲宇 奚潇睿 牛宝仪 杨明玉混合多端直流输电系统短路电流水平超标对其安全稳定运行造成极大威胁.现有通过控制策略限流的方法多以本站出口侧最严重的极间故障展开分析,忽略了过渡电阻对两侧系统的耦合作用,且控制参数的不合理配置会降低故障点非...参考文献和引证文献
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