文档名：直流电缆用交联聚乙烯绝缘的击穿概率及其尺度效应仿真
摘要：电力电缆在远距离大容量电力传输和海上风电并网中起着极其重要的作用.受直流电场影响,交联聚乙烯(XLPE)电缆存在着空间电荷积聚和电荷能量积累现象,导致绝缘材料被击穿而引发故障.该文建立电荷输运与分子链位移击穿模型,对XLPE介质中载流子输运和能量积累过程进行了仿真,得到XLPE特征击穿场强-试样厚度依赖特性以及击穿概率分布.仿真结果表明,XLPE直流击穿场强受尺度效应影响明显,击穿场强随着试样厚度的增加而减少,且击穿强度概率计算结果服从威布尔分布.建立电荷输运随机变量参数分散性与击穿概率分布的定量关系.随着试样厚度的增加,绝缘材料内部的缺陷分散性增加,电荷输运随机变量参数高斯分布中的方差增加,击穿威布尔分布形状参数减小.陷阱能级是影响击穿威布尔分布形状参数的最关键因素.该研究为电力电缆的优化设计和可靠性评估提供了仿真技术支撑.
Abstract：Powercablesplayanextremelyimportantroleinlong-distancehigh-capacitypowertransmissionandoffshorewindpowergridconnection.AffectedbyDCelectricfield,cross-linkedpolyethylene(XLPE)cablesaresubjecttospacechargeaccumulationandchargeenergyaccumulationphenomena,leadingtoinsulationmaterialbreakdownandcausingfaults.Accordingtothesoliddielectricscaleeffectprinciple,increasingthethicknessorareaofthespecimenwillresultinanincreaseinvolumeandanincreaseintheprobabilityoflocaldefects,causingthebreakdownfieldstrengthtodecrease.However,themicroscopicdefectparametervariationofinsulationmaterialswithspecimenthicknessanditsquantitativerelationshipwiththebreakdownprobabilityhaveyettobeclarified.Therefore,thispaperproposesachargetransportandmoleculardisplacementmodulatedmodel(CTMD),andstudiesthecharacteristicbreakdownfield-specimenthicknessdependenceofXLPEandtheprobabilitydistributionofthebreakdownfieldbythecarriertransportandenergyaccumulationprocessesinthedielectrics.Theelectrodesinjectholesandelectronsintothebulkofmaterialswhenarampvoltageisappliedtotheinsulatingmaterials.Undertheinfluenceoftheelectricfield,thesecarriersmoveintotheinsulatingmaterials.Deeptrapsaregeneratedattheinterfacesofthecrystalline/amorphouszone(theinterfacebetweensphericalcrystals)andformedpolargroupsinXLPE.Thedeeptrapscaptureholesandelectrons,causingdistortionsintheelectricfieldduetospacechargeaccumulation.Also,asthetrappedchargesarebeingaffectedbyCoulombforces,theexpansionofthefreevolumeduetomolecularchaindisplacementraisesthechargeenergythatistravelinginsideit.Thelocalcurrentsurgesandtheinsulatingmaterialisbrokenthroughwhenthechargeenergybuildsuptothepointofcrossingthetrappotentialbarrier.ThefindingsdemonstratethatthescaleeffecthasasubstantialimpactontheDCbreakdownfieldofXLPE.Thebreakdownfielddecreaseswithincreasingspecimenthickness,andthebreakdownstrengthprobabilityfollowstheWeibulldistribution.Additionally,thebreakdownprobabilitydistributionofXLPEcanbemodeledbyaddingrandomvariablestoCTMD.AlteringthevarianceofthechargetransportrandomvariablecontrolsthebreakdownWeibulldistribution'sshapeparameter.TheshapeparameterofthebreakdownWeibulldistributiondecreasesto10.12,5.76,5.49,5.36,and4.34asthespecimenthicknessincreasesfrom50μmto250μm.ThetraplevelmostsignificantlyinfluencestheWeibulldistribution,andthevalueoftheshapedistributionparametervariesthefastestwiththevariationofthetraplevel.Thefollowingconclusionsareobtainedfromthesimulations:(1)Acorrelationisestablishedbetweenthelong-rangemotionofmolecularchainsundertheactionofCoulombforcesandthethicknessdependenceofthebreakdownfieldofXLPE.Themolecularchainscontainingtrapchargeshavemoretimetoundergolong-rangemotionundertheelectricfieldasthespecimenthickensandthefreevolumeincreases.Atalowerelectricfield,thechargesgainenoughenergyinthefreevolumetocauseinsulationmaterialbreakdown.(2)IntheCTMDmodel,theprobabilitydistributionofthebreakdownfieldobtainedfromthesimulationobeystheWeibulldistribution.ItisfoundthatthetraplevelisthemostcriticalinfluencingfactoroftheshapeparameterofthebreakdownWeibulldistribution.(3)Asthespecimenthicknessincreases,thevarianceintheGaussiandistributionofthechargetransportrandomvariableparametersgraduallyincreases,theshapeparameterofthebreakdownWeibulldistributiongraduallybecomessmaller,andthedispersionofdefectsinsidetheinsulatingmaterialincreasessubstantially.
作者：朱敏慧 闵道敏 高梓巍 武庆周 Author：ZhuMinhui MinDaomin GaoZiwei WuQingzhou
作者单位：电力设备电气绝缘国家重点实验室(西安交通大学)西安710049中国工程物理研究院流体物理研究所绵阳621900
刊名：电工技术学报
Journal：TransactionsofChinaElectrotechnicalSociety
年，卷(期)：2024, 39(4)
分类号：TM85
关键词：交联聚乙烯 空间电荷 威布尔分布 尺度效应 陷阱能级
Keywords：Cross-linkedpolyethylene(XLPE) spacecharge Weibulldistribution sizeeffect traplevel
机标分类号：TM247TM726.4TM855
在线出版日期：2024年3月5日
基金项目：国家自然科学基金，国家自然科学基金，电力设备电气绝缘国家重点实验室项目直流电缆用交联聚乙烯绝缘的击穿概率及其尺度效应仿真[
期刊论文] 电工技术学报--2024, 39(4)朱敏慧 闵道敏 高梓巍 武庆周电力电缆在远距离大容量电力传输和海上风电并网中起着极其重要的作用.受直流电场影响,交联聚乙烯(XLPE)电缆存在着空间电荷积聚和电荷能量积累现象,导致绝缘材料被击穿而引发故障.该文建立电荷输运与分子链位移击穿模型...参考文献和引证文献
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