高電壓設(shè)備測(cè)試（High Voltage Equipment Testing）（英文版） 課件 Worksheet 1 Hot Washing

《HighVoltageEquipmentTesting》HotWashing主講人：何發(fā)武（副教授）OperatingWorksheet：OperatingWorksheet：TableofContents01Followme02Workshop03Training01FollowmeⅠ.OverviewofhotwashingAsatmosphericpollutionwillbeattachedtothemagneticcolumnoftheinsulatingporcelainvase,therainydaysarepronetopollution,whichcanleadtoinsulationbreakdownseriouslycausedbyshortcircuitsorgroundingaccidents,soitisnecessarytocleantheinsulatingpartofthesubstationequipmentregularlyinordertopreventthepollutionoftheequipment,toavoidthereductionoftheinsulationoftheequipment,whichwillleadtothebreakdownorshortcircuitdisconnectionaccidents,suchasshowninFigure4-1.Figure4-1

Isolatingswitchinshort-circuitdisconnectionaccidentⅠ.OverviewofhotwashingUsually,theelectricalequipmentworksinastrongelectricloadforalongtime.Thecomprehensivepollutantscausedbytheenvironment,oxidation,andslowcorrosioncausethecontactresistanceoftheelectricalequipmentcontactstoincreasesignificantly,andthearcingisseriouswhenthecontactsact,resultinginhigh-temperatureablation,damagetotheelectricalappliances,andevenaccidents.Powerequipmentoperatinginastrongelectromagneticfield,duetolong-termoutdoorexposure,hasastrongaffinityforvariouspollutantsintheenvironment.Ⅰ.OverviewofhotwashingOvertime,alayerofdirtaccumulates,posingthebiggestriskof“pollutionflashover”and“fogflashover.”Thisleadstosignificantdirectandindirecteconomiclosseseachyear.Therefore,itisnecessarytotimelyremovedust,oilstains,moisture,salt,andotherpollutantsfromvariouselectricalequipmentsuchasoverheadinsulatorsandrodinsulatorsofrailwaycatenarysystems,asshowninFigure4-2,inordertoreduceflashoverfaultsandpollutionflashoversofthesupportinsulatorsofthecatenarysystem.Figure4-2

ThesupportinsulatoroftheOCSexperiencingpollutionflashoverⅠ.OverviewofhotwashingItisimportanttoprioritizecleaningtheinsulatorsofthelineinthesubstation,theporcelainbottlesofthesupportcolumnsfordisconnectingswitches,andthebushingsofswitchtransformersinthesubstation.However,allconductivemetalpartswithinthestation,suchasthepowerlines,transformerbodies,andknifeswitchcontacts,shouldnotbecleaned.Itisalsocrucialtopreventwaterusedforcleaningfromenteringtheterminalboxesandavoidwateringresssecondarywiring,asshowninFigure4-3and4-4.Figure4-3

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kVstationtransformerFigure4-4

Theon-sitelayoutofincominglinesatasubstationⅠ.OverviewofhotwashingFigure4-5illustratestheon-sitehotwashingsceneatasubstation.Figure4-5

SubstationhotwashingscenesiteⅡ.Thefunctionsofhotwashing(1)Preventandeliminatepollutionflashoversandfogflashoversinpowerequipment,reducingandavoidingthesignificanteconomiclossescausedbypoweroutages.(2)Helpimprovetheelectricalinsulationvalueoftheequipmentandmitigatesecondarypollution.Itrestoresthenormalsurfaceimpedanceofcircuitboardsandcomponents,providingspecialprotectionandensuringthattheequipmentoperatesinoptimalconditions.Ⅱ.Thefunctionsofhotwashing(3)Reducethecontactresistanceofelectricalequipmentcontacts,reducethepowerconsumptionofelectricalequipment,andimprovetheworkingefficiencyofequipment.(4)Restorethenormalheatdissipationcapacityofelectronicequipment,reducethepowerconsumptionofelectricalequipment,andimprovetheworkingefficiencyofequipment.(5)Reducetheeconomiclossescausedbypoweroutagemaintenanceequipmentgreatly.02WorkshopⅠ.OperatingProceduresforHotWashing1.BasicSecurityMeasuresAnyoneenteringthelivecleaningandmaintenancesiteshouldweartheprescribedworkinguniformandcomplywiththerelevantsafetyregulationsoftheuser(suchaswearingasafetyhelmetwithafaceshield).Cleaningtoolsusedshouldhaveinsulatinghandles,andtheexposedconductivepartsshouldbeinsulatedtopreventaccidentalshortcircuitsduringoperation.Duringwork,insulatingshoes,cottonlong-sleevedworkclothes,andglovesshouldbeworn,andtheoperationshouldbeconductedwhilestandingonaninsulatingmatordryinsulatingmaterial.Figure4-6showspersonnelwearinginsulatingprotectivegearoperatingahandheldwatergun.Ⅰ.OperatingProceduresforHotWashingFigure4-6

PersonnelwearinginsulatingprotectivegearoperatingahandheldwatergunⅠ.OperatingProceduresforHotWashing2.SelectionofWaterResistanceRateandWaterColumnThepollutionintensityiscalledsaltdensity,whichreferstothemassofpollutantssuchascigaretteash,cementdust,andchemicalmaterialsthatadheretotheinsulationsurfaceofelectricalequipmentperunitareaduetoexternalenvironmentalpollution.Itisusedtomeasurethedegreeofinsulationcontamination,anditsunitismg/cm2.Ⅰ.OperatingProceduresforHotWashingThereisadifferenceininsulationbetweenwaterusedforhotwashingandordinarywater.Commonwatercontainsimpurities,andtapwateranddrinkingwateralsocontainvariousmineralions,whichcanconductelectricity.However,thewaterusedforhotwashingisindustriallyfilteredandhasaveryhighresistivity,equivalenttoaninsulatingmedium.Thisisthesafetystandardforhotwashing.Thewaterusedforhotwashingcannotbedrunkbyhumans.Ⅰ.OperatingProceduresforHotWashingBeforetheoperationofhotwashing,thecontaminationoftheinsulatorshouldbemastered.WhenthesaltdensityisgreaterthanthecriticalsaltdensityinTable4-1,itisgenerallynotsuitableforhotwashing,otherwise,thewaterresistancerateshouldbeincreased.hotwashingisnotsuitableforarrestersandpoorlysealedequipment.Table4-5

WaterResistivityandSpecificCreepageDistanceⅠ.OperatingProceduresforHotWashingTheresistivityofwaterusedforhotwashingisgenerallynotlessthan1,500·cm.Whenflushing220

kVsubstations,theresistivityofthewatershouldnotbelowerthan3,000·cm,anditshouldcomplywiththerequirementsinTable4-1.Beforeeachflushingoperation,theresistivityofthewatershouldbemeasuredusingaqualifiedresistivitymeter.Watersamplesshouldbetakenatthewateroutletformeasurement.Ifwateriscollectedincontainerssuchaswatertrucks,theresistivityofthewatershouldbemeasuredforeachbatch.Theresistivityofthewaterhasasignificantimpactonensuringthepersonalsafetyoftheoperatorsandthesafetyoftheequipment.Ⅰ.OperatingProceduresforHotWashingTheresistivityofwaterhasasignificantimpactonensuringthepersonalsafetyoftheoperatorsandthesafetyoftheequipment.Thisinfluenceismainlyreflectedintheinsulationlevelbetweenthewaterresistivityandthewatercolumn.Differentheightsofwatercolumnsanddifferentwaterresistivitiescorrespondtodifferentpowerfrequencydischargevoltages.Figure4-7showstherelationshipbetweenwaterresistivityanditspowerfrequencydischargevoltage.Figure4-7

RelationshipbetweenwaterresistivityandpowerfrequencydischargevoltageⅠ.OperatingProceduresforHotWashingToolsforhotwashingusewatercolumnsasthemaininsulation,whilewaterpipesandinsulationoperatingrodsserveasauxiliaryinsulation.Thewatercolumnisthekeycomponentthatwithstandsvoltage,buttheinsulationofthewatercolumnmainlydependsonitslength.Atthesametime,thediameterofthewatergunnozzlealsohasasignificantimpactontheinsulation.Ⅰ.OperatingProceduresforHotWashingLarge,medium,andsmallhotwashingtoolswithwatercolumnsasthemaininsulation(thosewithnozzlediametersof3

mmandbelowarecalledsmallwaterwashers;thosewithdiametersof4–8

mmarecalledmediumwaterwashers;thosewithdiametersof9

mmandabovearecalledlargewaterwashers).ThelengthofthewatercolumnbetweenthewatergunnozzleandthechargedelectrodemustnotbelessthantherequirementsspecifiedinTable4-2.Bothlargeandmedium-sizedwater-flushinggunnozzlesshouldbereliablygrounded.Table4-2

DistancebetweenthewatergunnozzleandthechargedelectrodeⅠ.OperatingProceduresforHotWashingIftheinsulationperformanceoftheinsulatorisfoundtobereduced,itshouldbereplacedfirstbeforeconsideringotherwork.Ifthereisnoreliabletechnicalmeansofidentification,damagedandlow-valueinsulationshouldnotbesubjectedtohotwashing.Whenwashinginsulators,attentionshouldbepaidtothewinddirection.Itisnecessarytowashthedownwindsidefirstandthentheupwindside.Forinsulatorsarrangedinupperandlowerlayers,thelowerlayershouldbewashedfirst,followedbytheupperlayer.Thewashingangleshouldalsobeconsideredtopreventnearbyinsulatorsfromexperiencingflashoverinthesplashingwatermist.Differentwashingsequenceswillresultindifferentinsulationsurfaceconditions,whichwillaffecttheflashovervoltage.Ⅰ.OperatingProceduresforHotWashingOnemethodistowashthelayerssequentiallyfrombottomtotoporfromtheconductorsideoutward,minimizingthewettingofthesplashingsurfaceandavoidingwettingofotherlayersofdirt.Anothermethodistowashfromtoptobottom,whichmayresultinpartialwettingoftheinsulationsurfacebeforetheupperlayerofdirtiscompletelywashedoff.Figure4-8showsafieldwheresequentialflushingisperformed.Ⅰ.OperatingProceduresforHotWashingHotwashingshouldgenerallybeconductedingoodweatherconditions.Itisnotsuitabletoconducthotwashingwhenthewindspeedexceeds4levels,thetemperatureisbelow0C,duringrainy,snowy,sandstorm,foggy,orthunderstormweather.Therefore,thereisnocontaminationofthewaterusedforhotwashingduringoperation.However,thewaterthathaspassedthroughthewashingequipmentmaywashawaythedirtonthesurfaceoftheinsulationequipment,makingthewaternolongerclean.Figure4-8

WashthesiteinsequenceⅠ.OperatingProceduresforHotWashingThesafetydistancebetweenapersonandachargedobjectmustnotbelessthantheregulationsspecifiedinTable4-3.Table4-3

VoltageLevelsandHumanSafetyDistancesⅠ.OperatingProceduresforHotWashingTheabove“safedistance”includestheminimumdistancebetweenthecleaningoperator’smetaltools(suchassprayguns,etc.)andtheenergizedequipmentbeingcleaned.Therefore,duringthehotwashingprocess,boththesupervisorandtheoperatormustpayattentiontotheirpositions,asshowninFigure4-9.Figure4-9

PositionsofpersonnelatthewashingsiteⅡ.WaterWashingVehicleDuetotheexposureofinsulatorsofelectrifiedrailwayoverheadcontactlinestotheexternalenvironmentthroughouttheyear,suspendedparticles,dust,smoke,andotherexternalsubstancesintheaircanadheretothem,formingaccumulateddirt.Thedirttightlybondswiththesurfaceoftheinsulatorsovertime,makingitdifficulttocleanevenwithnaturalwindandrain.Inhumidweather,somesaltcompoundsdissolveandtransformintoconductivewaterfilmsolutions.Ⅱ.WaterWashingVehicleTheaccumulateddirtonthesurfaceoftheinsulatorscontinuestoabsorbmoistureinharshweatherconditions,leadingtoanincreasingleakagecurrent.Thiscancausepollutionflashoversoftheinsulatorsundernormaloperatingvoltage,resultinginwidespreadandprolongedpowerfailuresthatposeaseriousthreattorailwaytransportationsafety.Currently,themainmethodusedindomesticelectrifiedrailwaypowersupplysectionstocleaninsulatorsismanualwipingduringpoweroutagesoftheoverheadcontactsystem.However,thismethodhasdrawbackssuchashighlaborintensity,lowefficiency,andpoorsafety.Manualwaterwashingbypersonnelalsoinvolvesaheavyworkloadandhighsafetyrisks.Ⅱ.WaterWashingVehicleInordertoremovetheaccumulateddirtonthesurfaceofcontactsysteminsulators,therailwaypowersupplydepartmenthasintroducedwater-washingvehiclesf