UPGRADE TRANSMISSION LINE CORRIDOR - pub.nl.ca ?· Upgrade Transmission Line Corridor – Bay d’Espoir…

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  • A REPORT TO

    THE BOARD OF COMMISSIONERS OF PUBLIC UTILITIES

    Electrical

    Mechanical

    '' ..,

    Civil/

    Protection & Control

    -

    Transmission & Distribution

    Telecontrol

    System Planning

    UPGRADE TRANSMISSION LINE CORRIDORBay d'Espoir to Western Avalon

    September 2011

    newfoundland labrador

    hydroa nalcor energy company

  • UpgradeTransmissionLineCorridorBaydEspoirtoWesternAvalon

    NewfoundlandandLabradorHydro i

    TableofContents

    1 INTRODUCTION................................................................................................................ 1

    2 PROJECTDESCRIPTION..................................................................................................... 3

    3 EXISTINGSYSTEM............................................................................................................. 73.1 AgeofEquipmentorSystem ............................................................................... 93.2 MajorWorkand/orUpgrades ............................................................................. 93.3 AnticipatedUsefullife........................................................................................ 103.4 MaintenanceHistory ......................................................................................... 113.5 OutageStatistics ................................................................................................ 113.6 IndustryExperience ........................................................................................... 123.7 MaintenanceorSupportArrangements............................................................ 133.8 VendorRecommendations ................................................................................ 133.9 AvailabilityofReplacementParts ...................................................................... 133.11 Retirements........................................................................................................ 143.12 SafetyPerformance ........................................................................................... 143.13 EnvironmentalPerformance.............................................................................. 143.14 OperatingRegime .............................................................................................. 14

    4 JUSTIFICATION ............................................................................................................... 154.1 NetPresentValue .............................................................................................. 354.2 LevelizedCostofEnergy .................................................................................... 354.3 CostBenefitAnalysis.......................................................................................... 354.4 LegislativeorRegulatoryRequirements............................................................ 364.5 HistoricalInformation........................................................................................ 364.6 ForecastCustomerGrowth................................................................................ 364.7 EnergyEfficiencyBenefits.................................................................................. 374.8 LossesDuringConstruction ............................................................................... 374.9 StatusQuo.......................................................................................................... 384.10 Alternatives........................................................................................................ 38

    5 CONCLUSION.................................................................................................................. 405.2 ProjectSchedule ................................................................................................ 41

  • UpgradeTransmissionLineCorridorBaydEspoirtoWesternAvalon

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    1 INTRODUCTION

    NewfoundlandandLabradorHydro(Hydro)ownsandoperateseleven230kVlinestotaling

    627kminlengthconnectingtheBaydEspoirGeneratingStationtothemajorloadcenters

    andgeneration intheeasternportionoftheprovince. Figure1providesadiagramofthe

    BaydEspoirEast230kVtransmissionsystem.

    Bayd'Espoir

    TL202

    TL206

    Sunnyside

    ComeByChance

    TL203

    TL207 TL237

    Holyrood

    WesternAvalon

    TL217

    TL201

    Hardwoods OxenPond

    TL218

    TL236

    TL242

    Transmissionlinecrossingsremovedforclarity

    Figure1BaydEspoirEast230kVTransmissionSystem

    TheBaydEspoirEast230kVtransmissionsystemischaracterizedasbeingaheavilyloaded

    system.Conversely,the230kVtransmissionsystemwestofBaydEspoirischaracterizedas

    beingamorelightlyloadedsystem.Table1providesasummaryofeastandwestloadsat

    thetimeofsystempeaksfortheperiod20062010.Bycomparisonthe230kV

    transmissionsystemeastofBaydEspoirisloadedtoapproximatelytwicetheloadingofthe

    230kVtransmissionsystemwestofBaydEspoir.Theheavyloadingontheeasternportion

    ofthesystemiscoupledwiththeincentivetoprovideleastcostpowertocustomersby

    minimizingHolyroodproductionandmaximizingproductionfromhydroelectricresources

    locatedinBaydEspoirandwest.Constantmonitoringoftheloadontheeasternportionof

    thesystemisthereforerequired.Thermalloadlimitsonthelinesmustbestrictlyenforced

    toavoidunacceptablelinesagand/orpotentialconductordamage.Furtherloading

    pressureswillbeplacedupontheBaydEspoirEastsystemwiththeadditionoftheVale

    processingplantatLongHarbourandhasalreadyoccurredduetothelossofloadandnet

    hydroelectricgenerationincreaseattributedtotheclosureoftheAbitibiBowaterpapermill

  • UpgradeTransmissionLineCorridorBaydEspoirtoWesternAvalon

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    inGrandFallsWindsor.

    Table1BaydEspoirEastandWest230kVTransmissionSystemPeakLoads2006to2010Year BaydEspoirEast1 BaydEspoirWest22006 836 4312007 848 4502008 827 4362009 858 4282010 833 378

    Notes1 BaydEspoirEastloadequaltoTL202andTL206flowplusParadiseRiver,Holyrood

    andHardwoodsgenerationattimeofpeak.2 BaydEspoirWestloadequaltoTL204andTL231flowplusCatArm,HindsLake,

    Stephenville,HawkesBay,St.AnthonyDieselPlantgenerationandNonUtilityGenerationpurchasesattimeofpeak.

    3 ConnaigrePeninsulaloadsnotincluded4 ValuesbasedontheHydroEnergyManagementSystem(EMS)hourlydataandnot

    weatheradjusted

    LowerChurchillImpacts

    GiventhattheLowerChurchillProjecthasyettoreceivefinalprojectsanction,analysisof

    theBaydEspoirEast230kVtransmissionsystemmustconsiderboththecontinuedIsolated

    IslandScenarioandtheLabradorInfeedScenario.Ineffect,theproposedprojectmustbe

    appropriatetoeitheranIsolatedIslandorLabradorInterconnectedfuture.

    Toaccomplishthis,theBaydEspoirEast230kVtransmissionsystemwassplitintotwo

    sectionsBaydEspoirtoWesternAvalonandWesternAvalontoSt.Johns.Thisproject

    considersonlytheupgraderequirementsfortheBaydEspoirtoWesternAvalonsectionof

    theBaydEspoirEast230kVtransmissionsystem.TheWesternAvalontoSt.Johnssection

    canonlybeconsideredoncethedecisionontheLowerChurchillProjectandsubsequent

    needfortheSoldiersPondTerminalStationismade.WiththefinaldecisionontheLower

    ChurchillProjectscheduledforlate2011orearly2012,Hydrointendstosubmitany

    necessaryupgradeprojectsfortheWesternAvalontoSt.JohnssectionoftheBaydEspoir

    East230kVtransmissionsystemassociatedwiththeproposedLowerChurchillProjectto

    TheBoardaspartofits2013capitalbudgetapplication.

  • UpgradeTransmissionLineCorridorBaydEspoirtoWesternAvalon

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    2 PROJECT DESCRIPTION TheUpgradeTransmissionLineCorridorBaydEspoirtoWesternAvalonprojectwill

    consistofanew230kVtransmissionline,188kminlengthconnectingBaydEspoirand

    WesternAvalonTerminalStations.Thisincludesconstructionofa230kVsteeltower

    transmissionlinecompletewithoverheadgroundwireoveritsentirelength.Aminimum

    conductorsizeof795kcmil,26/7ACSRDRAKEwitha75Cconductortemperaturerating

    or804kcmil54/19AACSR/TWwithan80Cconductortemperatureisrequiredtoprovide

    thenecessarythermalratingforthenewcircuit.AtBaydEspoirTerminalStation,three

    230kVcircuitbreakers,six230kVmotoroperateddisconnectswitchesandassociated

    controlpanelswillbeaddedtocompletethebreakerandonehalfarrangementonthefirst

    twolegsofthestationlayoutandaccommodatethenew230kVtransmissionline

    terminationonathirdleg.Figure2providesasinglelinediagramwiththeproposed

    additionsinred.

  • UpgradeTransmissionLineCorridorBaydEspoirtoWesternAvalon

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    Figure2BaydEspoirTerminalStation#2AdditionsforNew230kVTransmissionLine

    AtWesternAvalonTerminalStationanew230kVringbusconsistingoffour230kVcircuit

    breakersisproposedforthesouthernendoftheterminalstation.Ratherthanconstruct

    thenewringbususingtraditionalgasfilled,airinsulatedcircuitbreakersandmotor

    operateddisconnectswitches,Hydroisproposingtouseacompactgasinsulated

    switchgear(GIS)ringbusconfiguration.TherationalefortheuseoftheGISequipmentisto

    limitthecivilworksfortheringbusaddition.TheWesternAvalonTerminalStationis

    situatedonthesideofahillnearChapelArm.Thelandtothewestoftheterminalstation

    consistsofanupwardslopingsteepembankmentwhichhashaddrainageissuesinthepast.

    Excavationtothewestwouldtobeextremelycostlyasitwouldrequireadditionalslope

  • UpgradeTransmissionLineCorridorBaydEspoirtoWesternAvalon

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    stabilityanddrainageworkalongwithrelocationoftheexistingaccessroad.Thelandto

    theeastconsistsofadownwardslopingsteepembankmenttoRoute201.Expansioninthis

    directionwouldrequireextensiveamountsoffill.Ifacquisitionofbuildinglotsforprivate

    homesintheareaoftheWesternAvalonTerminalStationweretobepursued,aminimal

    extensiontothesouthsideofthestationcanbeaccommodatedtopermitinstallationof

    thecompactGISandaccessroadrealignment.AspartoftheGISringbusaddition,TL208

    willbereterminatedinthenewringalongwiththenew230kVtransmissionlinetoBay

    dEspoir.ThiswillimprovethereliabilityoftheTL208supplyasitwillnolongerbetripped

    duetoanoutageto230kVbusB1or230/66kVtransformersT1orT2.Figure3providesa

    singlelinediagramoftheWesternAvalonTerminalStationwiththeproposedadditions

    showninred.TheGISringbusadditionwillcontainonesparelineterminationforafuture

    230kVtransmissionlinetotheeast,if/whenitmayberequired.Hydrohassecuredthe

    landintheareatopermitthefuturelinetermination.

    TL201toHardwoods

    TL217toHolyrood

    TL203toSunnyside

    TL237toComeByChance

    TL208toLongHarbour

    66kV

    T1&T2230/66kV15/20/25MVA

    B1 230kV

    B2

    B3 230kV

    B4 138kV

    230/138kVT3&T425/33.3/41.7MVAT575/100/125MVA

    OutdoorGISModule

    NewtoBayd'Espoir

    FutureLineTermination

    Figure3WesternAvalonTerminalStationAdditionsforNew230kVTransmissionLine

    Itshouldalsobenotedthatthisprojectalsoincludesastudytoinvestigatesuspension

    insulatorsonTL206(BaydEspoirtoSunnyside).Theseareoriginalinsulatorsmanufactured

    byNEMAandareofthesamevintageastheCanadianPorcelain/CanadianOhioBrass

  • UpgradeTransmissionLineCorridorBaydEspoirtoWesternAvalon

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    insulatorsthathaveexperiencedsignificantcementgrowthandmechanicalfailureover

    time.However,thereislittleindustryinformationonthelongtermmechanicaland

    electricalperformanceoftheNEMAinsulators.ItissuspectedthattheNEMAinsulatorson

    TL206donotmeetHydrosexistingsuspensioninsulatorspecification.Toconfirmthe

    residualmechanicalstrengthoftheNEMAinsulatorsfollowing43yearsinservice,Hydrois

    proposingtoremovesamplestringsfromserviceandcompletelaboratorytesting.Costof

    thiscomponentisestimatedat$50,000.FollowingtestingHydrowillbeinabetterposition

    toreporttheconditionoftheTL206insulatorstotheBoardwitharecommendationona

    replacementprogramfortheNEMAinsulators.

    AsdiscussedintheJustificationSectionbelow,analysisindicatesthatthisnew230kV

    transmissionlineisrequiredtoincreasefirmsystemcapacityinboththecontinuedIsolated

    IslandScenarioandtheLabradorInterconnectedScenario.

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    3 EXISTINGSYSTEM

    TheexistingBaydEspoir toWesternAvalon transmissioncorridorconsistsof five230kV

    transmissionlinesincluding:

    TL202BaydEspoirtoWesternAvalon;

    TL203SunnysidetoWesternAvalon;

    TL206BaydEspoirtoWesternAvalon;

    TL207SunnysidetoComeByChance;and

    TL237ComeByChancetoWesternAvalon.

    Table2providestheratingofeachtransmissionlineforvaryingambienttemperature.

    Table2BaydEspoirtoWesternAvalonTransmissionCorridorLineRatingsMVARatingforanAmbientTemperatureofTL#

    30C 25C 15C 0C

    TL202 199.3 236.9 297.7 369.5

    TL203 261.7 278.0 307.8 347.0

    TL206 199.3 236.9 297.7 369.5

    TL207 355.8 375.5 411.5 459.6

    TL237 355.8 375.5 411.5 459.6

    Ofthesetransmissionlines,TL202andTL206arethemostheavilyloadedlinesduringthe

    latespringtoearlyfalltimeperiodwhentheHolyroodThermalGeneratingStationisshut

    downoroperatingatminimallevels.Thisisduetothefactthattheycarrytheloadsofboth

    theBurinandAvalonPeninsulasalongwithaportionoftheloadonthe138kVtransmission

    loopbetweenStonyBrookandSunnyside.LoadrelieftoTL202andTL206isprovidedbythe

    ParadiseRiverHydroelectricGeneratingStationandtheSt.LawrenceandFermeusewind

    farmswheninoperation.UnderalineoutagecontingencyHydrowillstartitscombustion

  • UpgradeTransmissionLineCorridorBaydEspoirtoWesternAvalon

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    turbinesatHolyrood(10MW)andHardwoods(46MW)toreducetheloadingonthe

    transmissioncorridor.Givenathermalratingof297.7MVAona15Cday(i.e.spring/fall)

    HydromustlimittheloadingonTL202andTL206toapproximately353MW(297.7+10+

    46=353.7)toensurethatTL202orTL206doesnotbecomeoverloadedshouldTL206or

    TL202trip.ConsequentlyforBaydEspoirEastloadsinexcessof353MWona15Cday,

    HydromustoperategenerationatitsHolyroodThermalGeneratingStation.

    ThisinefficiencyisfurtherillustratedinTable3,whichincludesthetriggersusedbySystem

    OperationstodeterminewhengeneratorsatHolyroodThermalGeneratingStationareto

    bebroughtonline.Inanoptimalsituation,thegeneratorsatHolyroodwouldonlybe

    dispatchedafterallhydroelectricgeneratorsontheislandarebroughtonline(while

    maintainingsufficientreservetowithstandthelossofthelargestunit).Theseoptimal

    thresholdsareindicatedinTable3.

    Duetotheexistingthermallimitations,generatorsatHolyroodmustbebroughtonlineat

    loadlevelsthataremuchlowerthantheoptimalvalues.TheHolyroodunitsaretherefore

    requiredtooperatemuchearlierinthefallandlaterinthespringthanwouldotherwisebe

    required.Thisproblemiscompoundedasthegeneratorsareoftendispatchedtoproducea

    minimaloutputpower(approximately70MW),resultinginahighlyinefficientuseoffuel.

    Table3ThresholdsforBringingGeneratorsOnlineatHolyroodThermalGeneratingStation

    NumberofHolyroodGeneratorsInService

    OptimalThresholdtoBringanAdditional

    HolyroodGeneratorOnline(MWofSystemGeneration)

    ThresholdtoBringanAdditionalHolyroodGeneratorOnline

    (MWofSystemGeneration)

    Threshold/OptimalThreshold

    0* 994 635 69.2%1* 1137 835 78.8%2 1319 960 77.3%

    *HolyroodUnitThreeonlineasaSynchronousCondenser

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    Whilethesefactorsdemonstratesignificantrestrictions intheoperationalflexibilityofthe

    existingtransmissionsystemeastofBaydEspoir,there isamuchgreaterconcernrelating

    totransfercapacity.IntheeventofthelossofaunitatHolyrood,theexistingtransmission

    systemwould be unable to supply system loads above 1280MW.While this analysis is

    describedindetailinSection4,itmaybenotedthatthepeakloadfor2012isforecastedto

    exceed 1350MW. The loss of a unit atHolyroodwould therefore result in a significant

    expo...