变电所中英文对照外文翻译文献.docx
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变电所中英文对照外文翻译文献
中英文对照外文翻译
ReliabilityofLightningResistant
OverheadDistributionLines
Lightingcontinuestobethemajorcauseofoutagesonoverheadpowerdistributionlines.Throughlaboratorytestingandfieldobservationsandmeasurements,thepropertiesofalightningstrokeanditseffectsonelectricaldistributionsystemcomponentsarewell-understoodphenomena.Thispaperpresentsacompilationof32yearsofhistoricalrecordsforoutagecauses,duration,andlocationsforeightdistributionfeedersattheOakRidgeNationalLaboratory(ORNL).
Distributiontypelightningarrestersareplacedatdead-endandanglestructuresatpolemountedwormerlocationsandathighpointsontheoverheadline.Stationclasslightningarrestersareusedtoprotectundergroundcableruns,padmountedswitchgearandunitsubstationtransformers.Resistancetoearthofeachpolegroundistypically15ohmsorless.Athigherelevationsinthesystem,resistancetoearthissubstantiallygreaterthan15ohms,especiallyduringthedrysummermonths.Atthesehighpoints,groundrodswererivenandbondedtothepolegroundingsystemsinthe1960'sinanattempttodecreaselightningoutages.Theseattemptswereonlypartiallysuccessfulinloweringtheoutagerate.Fromasurgeprotectionstandpointthevarietyofpolestructuresused(in-line,corner,angle,deadend,etc.)andthevarietyofinsulatorsandhardwareuseddoesnotalloweach13.8kVoverheadlinetobecategorizedwithauniformimpulseflashoverrating(170kV,etc.)oranumericalBILvoltageclass(95kVBIL;etc.).Forsimplicitypurposesintheanalysis,eachoverheadlinewascategorizedwithanominalvoltageconstructionclass(15kV,34kV,or69KV).Sixoftheeightoverheadlines(feeders1through6)werebuiltwithtypicalREAStandardhorizontalwoodcrossarmconstructionutilizingsingleANSIClass55-5porcelainpininsulators(nominal15kVinsulation).Theshieldangleoftheoverheadgroundwiretothephaseconductorsistypically45degrees.Oneoverheadline(feeder7)wasbuiltwithtransmissiontypewoodpoleconstructionbecausethelineextendedtoaresearchfacilitywhichwastohavegeneratedelectricalpowertofeedbackintothegrid.PolestructureofthislineareofdurablewoodcrossaconstructionwhichutilizedoubleANSI52-3porcelainsuspensioninsulatorstosupporttheconductors(nominal34kVinsulation).Theshieldangleoftheoverheadgroundwiretothephaseconductorsforfeeder7istypically30degrees.In1969,anoverheadline(feeder8)wasintentionallybuiltwith"lightningresistant"constructioninanattempttoreducelightningcausedoutages.Polestructuresofthelinehavephaseoverphase24-inchlongfiberglasssuspensionbracketswithdoubleANSI52-3porcelainsuspensioninsulatorstosupporttheconductors(nominal69kVinsulation).Theshieldangleoftheoverheadgroundwiretothephaseconductorsforfeeder8istypically30degrees.Thefailuredatawascompiledforeachoftheeight13.8kVfeedersandispresentedinTable,alongwithpertinentinformationregardingfeederconstruction,elevation,length,andage.
Akeyfindingofthefailureanalysisisthatweather-relatedeventsaccountforoverhalf(56%)ofthefeederoutagesrecorded.Fifty-sevenofthe76weather-relatedoutageswereattributedtolightning.Insulationbreakdowndamageduetolightningisalsosuspectedinatleastadozenoftheequipmentfailuresobserved.Thedataindicatesoverheadlineswhichpassoverhighterrainarelessreliablebecauseofthegreaterexposuretolightning.Forexample,feeder3hadthemostrecordedoutages(48),ofwhichtwo-thirdswereduetoweather-relatedevents;thisfeederisalsothehighestlineontheplantsite,risingtoanelevationof450abovethereferencevalleyelevation.Overheadlinesthatarelongerandtowhichmoresubstationsandequipmentareattachedwerealsoobservedtobelessreliable(moreexposuretolightningandmoreequipmenttofail).Theageofthelinedoesnotappeartosignificantlylessenitsreliabilityaslongasadequatemaintenanceisperformed;noneofthelineshavehadanotableincreaseinthefrequencyofoutagesasthelineshaveaged.Aswouldbeexpected,theempiricaldatapresentedinTableIconfirmsthetwooverheadlineswhichhavebeeninsulatedtoahigherlevel(34or69KV)havesignificantlybetterreliabilityrecordsthanthoseutilizing15kVclassconstruction.Feeder7(insulatedto34KV)andfeeder8(insulatedto69kV)havebadonly3outageseachovertheir32and23yearlifespans,respectively.Theselinesfollowsimilarterrainandarecomparableinlengthandagetothe15kVclasslines,yettheyhaveacombinedfailurerateof0.22failuresperyearversus4.32failuresperyearfortheremainingfeeders.
Ontypical15kVinsulatedlineconstruction,lightningflashoversoftencause60cyclepowerfollowandfeedertrip.Withthehigherinsulationconstruction,outageratesarereducedbylimitingthenumberofflashoversandtheresultantpowerfollowwhichcausesanovercurrentdevicetotrip.Thisallowslightningarresterstoperformtheirdutyofdissipatinglightningenergytoearth.Thenumberofrecloseractionsandtheirresultantmomentaryoutagesarealsoreduced.Thisisbeneficialforcriticalfacilitiesandprocesseswhichcannottolerateevenmomentaryoutages.Anadditionalbenefitisthatoutagesduetoanimalcontactarealsoreducedbecauseofthegreaterdistancefromphaseconductortogroundonpolestructures.Distributionlineequipmenttoincreaselineinsulationvaluesare"offtheshelf"itemsandproventechnology.Newlightningresistantconstructiontypicalbyutilizeshorizontallineposts,fiberglassstandoffbracketsoranyothermethodwhichworldincreasetheinsulationvalue.Thereplacementofstandardpininsulatorswithlinepostinsulatorsofgreaterflashovervalueisaneffectivemeanstoretrofitexistingwoodcrossarmconstruction.Thedoublingandtriplingofdeadendandsuspensioninsulatorsisalsoameansofincreasingflashovervaluesonexistingangleanddead-endstructures.Currentfiberglass,polymer,andepoxytechnologiesprovideanaffordablemeanstoincreaselineinsulation.
Whiletheuseofincreasedinsulationlevelstoreducelightningflashoversandtheresultantoutagesonoverheaddistributionlineshasbeenthoroughlytestedanddemonstratedinlaboratoryandexperimentaltests[5],longtermhistoryfielddatahaspositivelydemonstratedthattheuseof"lightningresistant"constructioncangreatlyreduceoutages.FielduseatORNLhasshownthatinareaswhicharevulnerabletolightning,theuseofincreasedinsulationandasmallershieldingangleisanimpressiveandcosteffectivemeanstoappreciablyincreasethereliabilityofoverheaddistributionlines.Thisreliabilitystudyclearlyillustratesthattheinsulationrequirementsforhigh-reliabilitydistributionfeedersshouldbedeterminednotbythe60Hzoperatingvoltagebutratherbywithstandrequirementsforthelightningtransientsorotherhighvoltagetransientsthatareimpressedupontheline.Electricalequipment(switchgear,insulators,transformers,cables,etc.)haveareserve(BElevelorflashovervalue)tohandlemomentaryovervoltages,andbyincreasingthatreserve,theservicereliabilityisappreciablyincreased.Astheelectricalindustrygraduallymovesawayfromstandardwoodcrossarmconstructionandmovestowardmorefiberglass,polymerandepoxyconstruction,increasedinsulationmethodscanbeappliedaspartofnewconstructionoraspartofanupgradeorreplacementeffort.Inconsideringneworupgradedoverheadlineconstruction,theincrementalincreasedcostofthehigherinsulationequipmentisdinproportiontothetotalcostsofconstruction(labor,capitalequipment,cables,electricpoles,right-of-wayacquisition),Itscosteffectivenessvarieswiththeapplicationandtheconditionstowhichitisbeapplied.Economicbenefitsincludeincreasedelectricalservicereliabilityanditsinherentabilitytokeepmanufacturingprocessesandcriticalloadsinservice.Othermoredirectbenefitsincludelessrepairofoverheaddistributionlines,whichcanhaveasignificantreductioninmaintenancecostduetolessreplacementmaterialsandalargereductioninovertimehoursformaintenancecrews.
抗雷击架空配电线路的可靠性
闪电仍然是架空配电线路上的中断1的主要原因。
通过实验室测试和现场观察和测量,雷击和其对配电系统组件的属性是很好理解的现象。
本文提出了一个32年的历史记录,停运的原因,时间,地点,在橡树岭国家实验室的八个配电馈线汇编。
配电型避雷器在死胡同和角度的结构被放置在极安装W奥莫尔的位置,并在高点上的架空线。
站级避雷器是用来保护地下电缆运行,垫置式开关柜,单位变电站变压器。
每个极接地的接地电阻通常是15欧姆或更小。
在高海拔系统中,基本上是对地电阻大于15欧姆,尤其是在干燥的夏季。
在这些高点,研磨棒极接地系统,在1960年,企图以减少雷击停电驱动和保税。
这些尝试只是部分成功地降低停电率。
从浪涌保护的角度来看,使用各种不同的杆件结构(列直插式,角,角,死路,等),和绝缘体及使用的硬件的各种不允许每13.8千伏架空线具有均匀的冲击闪络分类评价(170千伏,等)或一个数值的的BIL电压类(95千伏BIL,等等)。
在分析中为了简单起见,每个分类的额定电压建筑类(15千伏,34千伏,69千伏)架空线。
六七八个架空线(馈线1至6)建立典型的REA标准水平木横担,利用单级的ANSI55-5瓷针式绝缘子(标称15千伏绝缘)。
架空地线相导线的屏蔽角通常是45度。
一架空线(馈线7)建延长线传输型木杆建设,因为这是已产生的电能反馈到电网的研究设施。
这条线极结构耐久的建设的其中利用双ANSI52-3瓷悬式绝缘子支持(标称34千伏绝缘)。
馈线7的架空地线的相导体的屏蔽角通常是30度。
在1969年,架空线(馈线8)有意建立“抗雷击”试图减少雷电造成的停电。
该行的极结构阶段阶段超过24英寸长的玻璃纤维悬挂支架与双ANSI52-3瓷悬式绝缘子,支持标称69千伏绝缘的导体。
馈线8架空地线的相导体的屏蔽角通常是30度。
编制各八个13.8千伏馈线故障数据列于表I中,沿馈线结构,海拔高度,长度,和年龄的相关信息。
故障分析的一个重要发现是,与天气有关的事件占了一半以上(56%)的馈线停电记录。
五十七名76天气有关的中断是由于雷击。
绝缘击穿损坏,由于雷击还涉嫌至少有十几观察到的设备故障。
数据表明架空线路经过地势高,是不可靠的,因为雷击风险更大。
例如,馈线3最录制中断(48),其中三分之二是由于与天气有关的事件,这也是最高的馈线线厂区,上升到海拔450英尺以上的参考山谷高度。
也观察到架空线更长,更多的变电站和设备连接不可靠(多接触雷击和更多的设备失败)。
行的年龄似乎并不显着减轻其只要足够的维护;线中断的频率有一个显着的增加作为线路岁。
正如所预料的,实证的数据列于表我确认两架空线路绝缘已到一个更高的水平(34或69千伏),有显着更好的可靠性记录比那些利用15千伏级建设。
馈线7(绝缘的34千伏)和馈线8(绝缘的69千伏)每过32年和23年的寿命只有3停电有坏。
下面的几行类似的地形,在15千伏级线路长度和年龄相媲美,但他们有一个合并的失败率每年0.22次失败与4.32每年剩余的馈线故障。
在典型的15千伏绝缘线建设,雷电闪络往往造成60循环发电后续和馈线跳闸。
具有较高的绝缘结构,减少停机率次数限制的闪络,这会导致过电流跳闸的移动设备以所得的功率后续。
这使避雷器雷电能量耗散地球履行抚养义务。
重新接近的行动和其产生的瞬间中断的数量也减少了。
这有利于对关键设备和工艺无法容忍甚至瞬间停电。
另外一个好处是,由于动物接触的停电也减少了,因为更大的距离从相导