文档名：计及双界面的电缆绝缘水树缺陷时域反射解析模型
摘要：配电网中中压电缆的敷设条件相对较差,在环境水分和工作电压等因素的共同作用下容易在绝缘中生成水树缺陷,影响电缆绝缘的性能.时域反射法(TDR)可用于检测电缆故障,近来也有研究将其用于检测电缆绝缘局部缺陷,但检测结果与绝缘缺陷情况的关联尚不明晰.针对此问题,该文基于等效电路原理推导了同轴绝缘含水树缺陷时的等效介电常数,在此基础上结合传输线理论建立计及双界面反射的时域解析模型,可用于分析与预测电缆绝缘局部存在水树缺陷时TDR实验的反射波形.通过制作含模拟水树的电缆试样并进行TDR实验,考察了模拟水树缺陷的含水量、缺陷段长度和电导率等因素对TDR实验结果的影响.结果显示,模拟水树的TDR实验结果与解析模型的计算结果具有较好的对应性,初步验证了该模型用于分析与预测电缆绝缘局部缺陷反射特性的有效性.预期该解析模型有助于为TDR在电缆绝缘水树检测中的应用提供参考.
Abstract：Duetothepooroperatingenvironment,mediumvoltagecablesindistributionnetworksarepronetowatertreeagingunderthecombinedeffectofmoistureandvoltage,whichcandegradetheinsulationperformance.Thetime-domainreflectometry(TDR)methodcanbeusedtodetectcablefaults,andsomerecentstudieshaveusedittodetecttheagingofthelocalinsulationofcables.However,therelationshipbetweenthedetectionresultsandtheagingconditionoftheinsulationisnotclear.Toaddressthisproblem,anequivalentpermittivityforthecoaxialinsulationwithwatertreedefectsisderived.Moreover,atime-domainanalyticalmodelconsideringthereflectionofdualinterfacesisdevelopedtoanalyzeandpredicttheresultsofTDRexperimentsoncableswithlocalwatertreedefects.First,theequivalentpermittivityofthecoaxialinsulationwithwatertreeswasderivedbasedoncircuittheory,andtheeffectivenessofusingtheequivalentpermittivitytocharacterizethereflectioncharacteristicsofwatertreedefectsincableinsulationwasverifiedthroughfiniteelementsimulation.Then,atime-domaindual-interfacereflectionmodelconsideringtheinterfacesatbothendsofthedefectwasestablishedbasedontransmissionlinetheoryandtheequivalentpermittivity.Thismodelwasusedtoanalyzetherelationshipbetweenthereflectionofwatertreedefectsandtheconditionofwatertreeingaswellasthecharacteristicsoftheinputsignal(suchasamplitudeandwaveform).Finally,bymakingcablesampleswithmimicwatertreedefectsandconductingTDRtests,theeffectsoffactorssuchaswatercontent,length,andconductivityofthedefectsonTDRtestresultswereinvestigated.TheresultsshowedthattheTDRtestresultsofthemimicwatertreedefectsagreedwellwiththecalculatedresultsoftheproposedanalyticalmodel,preliminarilyvalidatingtheeffectivenessoftheproposedmodelforanalyzingandpredictingthereflectioncharacteristicsoflocalwatertreedefectsincableinsulation.Thefollowingconclusionscanbedrawnfromthisstudy:(1)Theequivalentpermittivitycancharacterizethewavereflectioncharacteristicsoflocaldefectsincableinsulation.Theproposedanalyticalmodelconsideringmultiplereflectionsatbothendsofthedefectcanmoreaccuratelypredictthereflectedwaveformgeneratedbylocalinsulationdefects.(2)TheTDRexperimentsonthemimicwatertreedefectsshowedthatthereflectionmagnitudeandwaveformwerecloselyrelatedtothewatercontent(quantityofthemimicwatertrees)andlengthofthedefectivesection.Forexample,inthisexperiment,adding5smallholestothedefectivesectionincreasedtheamplitudeofthereflectedwaveto2.6timestheoriginalvalue,whiledoublingthelengthofthedefectivesectionincreasedtheamplitudeofthereflectedwaveto1.6timestheoriginalvalue.ThispreliminaryresultindicatesthatTDRmeasurementscanprovideabasisforassessingtheextentandrangeofsimilarinsulationdefects(suchaslocalizedmoistureandwatertreeing).TheanalyticalmodelestablishedinthisstudyhelpstolinkthewatertreeingconditionofcableinsulationwithTDRtestresults,anditisexpectedtoprovideareferencefortheapplicationofTDRtestingindetectingwatertreeingincableinsulation.
作者：叶源 胡晓 Author：YeYuan HuXiao
作者单位：国网三明供电公司三明365000;贵州大学电气工程学院贵阳550025贵州大学电气工程学院贵阳550025;浙江大学电气工程学院杭州310027;浙江天际互感器股份有限公司江山324100
刊名：电工技术学报
Journal：TransactionsofChinaElectrotechnicalSociety
年，卷(期)：2024, 39(1)
分类号：TM247
关键词：电力电缆 绝缘老化 水树 有限元 时域反射 双界面
Keywords：Powercable insulationaging watertree finiteelement(FEM) timedomainreflectometry(TDR) dualinterfaces
机标分类号：TM711TM247TU473
在线出版日期：2024年1月18日
基金项目：浙江天际互感器股份有限公司企业博士后科研项目计及双界面的电缆绝缘水树缺陷时域反射解析模型[
期刊论文] 电工技术学报--2024, 39(1)叶源 胡晓配电网中中压电缆的敷设条件相对较差,在环境水分和工作电压等因素的共同作用下容易在绝缘中生成水树缺陷,影响电缆绝缘的性能.时域反射法(TDR)可用于检测电缆故障,近来也有研究将其用于检测电缆绝缘局部缺陷,但检测结果...参考文献和引证文献
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计及双界面的电缆绝缘水树缺陷时域反射解析模型 A Dual Interface Analytical Model for Time-Domain Reflectometry of Water Tree Defects in Power Cables
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