文档名：土壤电阻率的负温特性及冻土对接地极冲击响应的影响
摘要：西藏地区由于独特的气候与地理环境,在其冻土地区存在雷电与低温共存现象.低温下冻土作为含冰复杂体系,其在雷击下的冲击散流性能仍不明晰,因此该文就冻土电阻率的负温特性以及接地极的冲击特性开展研究.首先研究了不同含水量、含盐量的土壤电阻率随温度的变化规律;然后在冲击电流作用下,以永冻土试品的表层土壤融化厚度和季节性冻土试品的表层土壤冻结厚度为变量,探究了其对相应冻土中垂直接地极暂态电位的影响规律;最后结合冻结条件下土壤冲击放电的形貌特征与地中电场强度和电流密度的分布特性,探讨了负温下接地极暂态电位变化的本质原因.试验研究表明:考虑盐分对土壤的影响,当其温度在一次冻结温度Tf与二次冻结温度Ts之间时,电阻率随温度下降缓慢上升,只有当温度降至二次冻结温度时,才存在突增现象;在永冻土中,当冻土温度高于Ts时,接地极仍具有较好的散流性能.由此可知降低Ts可以减小水分冻结对土壤电阻率的影响,为避免极寒地区接地极失效提供了新思路.
Abstract：DuetotheuniquegeographicallocationandclimateenvironmentinTibet,thecoexistenceoffrozensoilandlightningcurrentexistsinthelowtemperaturearea,andthegreenenergytransmissionchannelisdifficulttoavoidthelowtemperaturearea.However,asacomplexsystemofwater,ice,airandsoilparticlescontainingiceatnegativetemperature,thevariationofsoilresistivitywithtemperatureunderdifferentwaterandsaltcontentsandtheimpulsecharacteristicsofgroundingdevicesinfrozensoilunderlightningcurrentarestillunclear.Therefore,inviewoftheaboveproblems,ontheonehand,thechangeofresistivitywithtemperatureof16soilsampleswithdifferentwatercontentandsaltcontentwasmeasuredbythequadrupolemethod,andthereasonsforthechangeofsoilresistivitywereanalyzedbycombiningthesoilconductivitymechanismandthecalculationformulaofunfrozenwatercontent;ontheotherhand,basedonthesimilarityprincipleofthescaleexperiment,takingthesurfacesoilfreezingthicknessoftheseasonalfrozensoilsampleandthesurfacesoilmeltingthicknessofthepermafrostsampleasvariables,theinfluencelawoftheverticalgroundingelectrodetransientpotentialinthecorrespondingfrozensoilsamplewasexplored.Furthermore,theX-rayimagingdevicewasusedtoobservethedischargeimageoftheimpulsecurrentinthefrozensoilsampleandthenumericalsimulationresultsofelectricfieldintensityandcurrentdensityinthefrozensoilwerecombinedtoexplaintheexperimentallaw.Themeasurementresultsofsoilresistivityatdifferenttemperaturesshowthatwhenthetemperatureofsalinesoilishigherthanthesecondaryfreezingtemperature(Ts),itsresistivityincreasesslowlywiththedecreaseoftemperature;whenthetemperatureislowerthanTs,theresistivityhasasuddenrise.TheresultsofimpulsecurrentdispersionexperimentofgroundingelectrodeinpermafrostshowthatwhenthetemperatureofpermafrostlayerishigherthanTs,thepermafroststillhasgoodcurrentdispersionperformance;themeltingthicknessofsurfacesoilincreases,andthepotentialofgroundingelectrodedecreasesslowly;whenthemeltingthicknessexceedsitsend,thepotentialdecreasesgreatly;however,whenthetemperatureofthefrozensoillayerislowerthanTs,thefrozensoilwithgreatresistivitywillforcethecurrenttodisperseinthesurfacethawingsoil,andthegroundingelectrodepotentialisverysmall.Theimpulsecurrentdispersiontestresultsofthegroundingelectrodeinseasonalfrozensoilshowthatthegroundingelectrodepotentialwillriseslowlywiththeincreaseofthefreezingthicknessofthesurfacesoil;whenthefreezingthicknessexceedsitsend,thepotentialrisebecomeslarger.Thefollowingconclusionscanbedrawnfromtheanalysisoftheresults:(1)WhenthetemperatureofsalinefrozensoildecreasestoTs,alargeamountofnon-conductiveiceandwatersaltwillbegenerated,andthewatercontentwilldecreasesharply,resultinginasuddenincreaseinsoilresistivity.(2)Thedischargeimageobservationresultsandnumericalsimulationresultsofimpulsecurrentinfrozensoilshowthatthecurrentdispersionperformanceoffrozensoilisinferiortothatofthawedsoil,andthesoilionizationdegreearoundthegroundingextremeisthemostserious,whilethesoilionizationisbeneficialtotheendcurrentdispersion,therefore,whenthethicknessofthesurfacesoilisgreaterthanthelengthoftheverticalgroundingelectrode,thechangerangeofthetransientpotentialofthegroundingelectrodewillbegreater.ItcanbeseenfromtheabovethatbyreducingtheTsofthesoil,thegroundingperformanceofthegroundingdevicecanbeavoidedtofailunderextremelycoldconditions.
作者：袁涛 任健行 司马文霞 常飞童 蔡永翔 肖小兵 Author：YuanTao RenJianxing SimaWenxia ChangFeitong CaiYongxiang XiaoXiaobing
作者单位：输变电装备技术全国重点实验室(重庆大学)重庆400044贵州电网有限责任公司电力科学研究院贵阳550000
刊名：电工技术学报
Journal：TransactionsofChinaElectrotechnicalSociety
年，卷(期)：2024, 39(5)
分类号：TM863
关键词：接地 冻土 冲击电流 极寒低温 土壤电离
Keywords：Grounding frozensoil impulsecurrent extremelycoldtemperature soilionizaion
机标分类号：U661.4O347TU411.2
在线出版日期：2024年3月19日
基金项目：国家自然科学基金土壤电阻率的负温特性及冻土对接地极冲击响应的影响[
期刊论文] 电工技术学报--2024, 39(5)袁涛 任健行 司马文霞 常飞童 蔡永翔 肖小兵西藏地区由于独特的气候与地理环境,在其冻土地区存在雷电与低温共存现象.低温下冻土作为含冰复杂体系,其在雷击下的冲击散流性能仍不明晰,因此该文就冻土电阻率的负温特性以及接地极的冲击特性开展研究.首先研究了不同...参考文献和引证文献
参考文献
引证文献
本文读者也读过
相似文献
相关博文
土壤电阻率的负温特性及冻土对接地极冲击响应的影响 Negative Temperature Characteristics of Soil Resistivity and Influence of Frozen Soil on Impulse Response of Grounding Electrode
土壤电阻率的负温特性及冻土对接地极冲击响应的影响.pdf
- 文件大小:
- 2.1 MB
- 下载次数:
- 60
-
高速下载
|
|
