Page 1
HVDCTRANSMISSIONSYSTEMFORRURALALASKAAPPLICATIONSPhaseII‐PrototypingandTesting
May2012FINALREPORT,Version1.1
preparedby
polarconsultalaska,inc.1503West33rdAvenue,Suite310Anchorage,Alaska99503Phone:(907)258‐2420
fundingagency
TheDenaliCommission510LSt.,Suite410Anchorage,Alaska99501Phone:(907)271‐1414
projectadministrator
AlaskaCenterforEnergyandPowerUniversityofAlaska,Fairbanks814AlumniDr.P.O.Box755910Fairbanks,Alaska99775Phone:(907)474‐5402
Page 2
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012
AbouttheCoverImage:
ThecoverimageisofademonstrationinstallationinFairbanksofaguyedfiberglasspolesimilarinsize,height,andconstructiontothepolesconsideredinthisstudyforoverheadtransmissioninruralAlaskaapplications.Thepoleisa12‐inch‐diameter,60‐foot‐tallfiberglassstructuresupportedbythreemicro‐thermopiles.Thepole’sfourguysareanchoredbytwomicro‐thermopilesandtwoscrewanchorssetinsilt‐richpermafrost.
Page 3
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE I
EXECUTIVESUMMARY
ProgramObjectives
ThisreportpresentstheachievementsandfindingsofPhaseIIofthe“High‐VoltageDirectCurrent(HVDC)TransmissionSystemsforRuralAlaska”researchanddevelopment(R&D)program.ThegoalofthisprogramistoimprovetheeconomicviabilityofAlaska’sruralcommunitiesbyprovidingmoreaffordableelectricitytransmissionalternatives.PhaseIIworkwasfundedbytheDenaliCommissionandcompletedbyPolarconsultAlaska,Inc.(Polarconsult)undercontracttotheAlaskaCenterforEnergyandPower(ACEP).
TheeffectofexcessiveenergycostscontinuestodegradethequalityoflifeinAlaska’sruralcommunitiesandplacestheseindigenouspopulationsatsevererisk.Nearly80%ofruralcommunitiesaredependentondieselfuelfortheirprimaryenergyneeds.Someofthepooresthouseholdsspent47%oftheirincomeonenergyin2008,morethanfivetimestheamountinAnchorage(CWN,2012).
HVDCintertieswillsupportmorecost‐effectivedevelopmentoflocalenergyresources,suchaswind,hydro,biomass,geothermal,hydrokinetic,gas,andcoal.Reducingthecostoflow‐power(1megawatt[MW]andless)intertiesbyusingHVDCsystemscanenableincreasedinterconnectionofruralcommunitiestoAlaska’sabundantenergyresources.
HVDCintertieswillalsobenefitruralcommunitieswithreducedenergycostsbybuildingeconomicsofscaleinruralpowergridsandallowingutilitiestoconsolidatebulkfuelfacilitiesanddieselelectricpowerplantsintomoreefficientandlower‐costconfigurations.
Asaresultofongoingadvancesinpowerelectronics,small‐scaleHVDCintertiesarenowfeasible.Thisreporthasidentifiedlow‐poweroverheadandsubmarineHVDCtransmissionsystemsasaneconomicallysuperioralternativetoconventionalalternatingcurrent(AC)interties.AdditionalcostreductionscanberealizedbyintegratingHVDCsystemswithfutureexpansionofbroadbandfiber‐optictelecommunicationnetworks.ThissynergisticopportunitybetweenthetelecommunicationsandelectricindustriesisoneofseveralreasonsHVDCintertiescanhelpsurmounttheeconomicbarriersfacingAlaska’sruralcommunities.
ComparativeanalysisofHVDCtransmissionsystemswithconventionalACsystemsindicatessignificanttechnicalandeconomicadvantagesofHVDCsystems.InmanyruralAlaskaapplications,theuseofHVDCsystemswillsignificantlylowerintertiecosts.
PhaseIIObjectivesandFindings
PhaseIIofthisR&DprogramfollowsthePhaseI–PreliminaryDesignandFeasibilityAnalysisFinalReport(Polarconsult,2009).PhaseItasksincludedassessingconvertertechnicalfeasibilityandevaluatingtheeconomicsofalow‐powerHVDCsystemsizedforruralAlaskaapplications.BasedonthefavorableresultsofthePhaseIproject,thefollowingPhaseIIobjectiveswereestablished:
● ConfirmationofthetechnicalfeasibilityoftheHVDC/ACpowerconvertertechnologybydesigning,building,andtestingafull‐scaleprototypeofa1‐MWbidirectionalpowerconverterandkeytransmissionsystemelements.
Page 4
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE II
● Confirmationoftheeconomicfeasibilityofthelow‐powerHVDCsysteminruralAlaskaapplicationsbydeterminingthecommercialcostoftheconverter,theconverter’sefficiency,andtheestimatedoverallcostsofanHVDCsystem.
● DevelopmentofcostestimatesforHVDCtransmissionsystemsandcomparisonwithconventionalACsystemstoquantifythebenefitsandsavingsofHVDCsystems.
PhaseIIhasdemonstratedthattheconvertertechnologyistechnicallyviableandthetransmissionsystemiseconomicallyfeasible.KeyPhaseIIfindingsare:
● Low‐powerHVDCconvertertechnologyisexpectedtobecommerciallyavailableat$250perkilowattperconverter.
● Estimatesofconstructioncostsforaconceptual25‐mileoverheadHVDCintertieindicatecapitalcostsavingsofapproximately30%comparedwithaconventionaloverheadACintertie.Estimatedlife‐cyclecostsrangefrom79%to107%ofthelife‐cyclecostofanACintertie.
● LongeroverheadHVDCintertiescanexpectcapitalcostsavingsofupto40%.
● PhaseIIanalysisalsoindicatesthatsignificantsavingsarepossibleforsubmarinecableandundergroundcableapplicationsusingHVDCsystems.Estimatedcapitalcostsavingsona25‐milelow‐powerHVDCsubmarinecableintertieareover50%comparedtoACalternatives.
BasedonPhaseIIfindings,thebenefitsoflow‐powerHVDCsystemsforAlaskaaresubstantial,andcontinueddevelopmentofthissystemisrecommended.
OpportunitiesandBarriers
BasedonanalysisandstudyconductedduringthisPhaseIIproject,PolarconsulthasconcludedthatthisHVDCtechnologypresentsthefollowingopportunitiesforAlaska’sutilityindustryandruralcommunities:
● Lessexpensiveruralelectricinterties,leadingtolower‐costenergyandincreasedenergyindependenceforruralcommunities.
● Interconnectiontocurrentlystrandedlocalenergyresources.
● Interconnectioncostsavingsbycombiningruralelectricandtelecommunicationsinterties.
Thesuccessfulcommercializationandadoptionoflow‐powerHVDCtechnologyinAlaskarequiresovercomingthefollowingbarriers:
● Completionofthecommercialdevelopmentanddemonstrationoftheconvertertechnology.Continueddevelopmentoftheprototypeconverters,culminatinginindependenttestingoftheconvertersanddeploymentonanAlaskautilitysystem,isneededtoprovethattheconvertersareacommerciallyviabletechnology.
● Acceptanceanduseoflow‐powerHVDCtechnologybyAlaska’sutilityindustry.Continuedinvolvementofin‐stateandinternationalstakeholderswiththeongoingdevelopmentofthistechnologyisconsiderednecessarytosurmountingthisbarrier.
● Developmentanddemonstrationofstandardsandcontrolprotocolsforlow‐powermultiterminaldirect‐current(MTDC)transmissionnetworks,whichareneededtobuildcost‐effectiveregionalHVDCpowernetworksinruralAlaska.
Page 5
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE III
Recommendations
Basedontheconclusionsandfindingsofthisproject,thefollowingactionsarerecommended:
PhaseIIIprogramactivities:
● Continueddevelopmentofthepowerconvertertechnologytocommercializetheexistingprototypeconverterdesign.SolicitationofadditionalHVDCconvertermanufacturersiswarrantedtoencouragediversityofsuppliersandcompetition;
● Independenttestingoftheconverterstovalidateefficiencyandperformance,followedbydeploymentonanAlaskanutilitysystemtovalidatefunctionalityandreliabilityinacommercialsetting;
● FurtherdevelopmentofMTDCtransmissionsystemsinterconnectionandcontroltechnologies;and
● Continuedinvolvementofin‐statestakeholdersinthedevelopmentofthistechnology.
Stakeholderactions:
● Incorporatelow‐powerHVDCtechnologyintoAlaska’sregionalandstatewideenergyplansandpolicies;
● ContinuecoordinationwiththeStateofAlaskatoallowaproject‐specificwaiveroftheNationalElectricalSafetyCode(NESC)toallowtheuseofsingle‐wireearthreturn(SWER)circuits;
● EncourageplannedruralpowerandtelecommunicationsintertiestoincorporateHVDCtechnologyintheireconomicandtechnicalanalysis,aswellastheirenvironmentalandpermittingreviewprocesses;
● Engagethetelecommunicationsindustrytoraiseawarenessofthesynergiespossiblebetweenlow‐powerHVDCtransmissionandfibernetworksinruralAlaska;and
● Collaboratewithinternationalstakeholderstoidentifysynergiesandlessonslearnedfromparalleltechnologydevelopmentefforts.Coordinateondevelopmentofapplicablepolicies/standardsandidentificationofmarketstohelpexpeditethecommercializationandreducethecostsoflow‐powerHVDCsystems.
Page 6
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE IV
TABLEOFCONTENTS
EXECUTIVESUMMARY...........................................................................................................................................................I
1.0 INTRODUCTION........................................................................................................................................................1 1.1 REPORTORGANIZATION...................................................................................................................................................2
1.2 ACKNOWLEDGEMENTS......................................................................................................................................................3
1.3 DISCLAIMER.........................................................................................................................................................................4
1.4 COPYRIGHTNOTICE...........................................................................................................................................................4
2.0 BACKGROUND............................................................................................................................................................5 2.1 PROGRAMOVERVIEW........................................................................................................................................................6
2.2 STAKEHOLDERADVICE......................................................................................................................................................7
3.0 HVDCTRANSMISSIONSYSTEMDESCRIPTION............................................................................................8 3.1 HVDCBACKGROUND........................................................................................................................................................8
3.2 HVDCSYSTEMCONFIGURATIONS................................................................................................................................10
3.3 COMPARISONOFACTOHVDCTRANSMISSION.........................................................................................................16
3.4 OVERHEADINTERTIEALTERNATIVES.........................................................................................................................17
3.5 SUBMARINECABLEINTERTIEALTERNATIVES...........................................................................................................19
4.0 HVDCCONVERTERSTATIONS.........................................................................................................................20 4.1 OVERVIEW........................................................................................................................................................................20
4.2 CONVERTERDEVELOPMENTOVERVIEW.....................................................................................................................20
4.3 ADDITIONALEQUIPMENT..............................................................................................................................................28
5.0 DESIGNCONCEPTSFOROVERHEADINTERTIES....................................................................................29 5.1 OVERHEADDESIGNAPPROACH....................................................................................................................................29
5.2 GEOTECHNICALCONDITIONS........................................................................................................................................30
5.3 ENVIRONMENTALLOADS...............................................................................................................................................30
5.4 CONSTRUCTION,RUSSTANDARDPRACTICE..............................................................................................................30
5.5 CONSTRUCTION,ALASKA‐SPECIFICCONCEPT............................................................................................................31
5.6 TESTINGOFOVERHEADDESIGNCONCEPTS...............................................................................................................32
6.0 SYSTEMECONOMICS...........................................................................................................................................37 6.1 COSTCOMPARISONOFACANDHVDCOVERHEADINTERTIES..............................................................................37
6.2 CASESTUDIES..................................................................................................................................................................41
7.0 CONCLUSIONSANDRECOMMENDATIONS................................................................................................49 7.1 CONCLUSIONS...................................................................................................................................................................49
7.2 OPPORTUNITIESANDBARRIERS...................................................................................................................................49
7.3 RECOMMENDATIONS.......................................................................................................................................................50
Page 7
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE V
LISTOFTABLES
Table6‐1 EstimatedLife‐CycleCostsfor25‐mileOverheadACandHVDCInterties......................39
Table6‐2 SummaryofCaseStudies......................................................................................................................42
Table6‐3 EstimatedCostforaGreensCreek–HoonahHVDCIntertie.................................................44
Table6‐4 EstimatedBenefit‐CostRatioofGreensCreek–HoonahHVDCIntertie..........................45
Table6‐5 EstimatedInstalledCostfora5‐MWPilgrimHotSprings–NomeIntertie....................48
LISTOFFIGURES
Figure3‐1 TypicalLargeHVDCStation....................................................................................................................9
Figure3‐2 ThreeTypesofIntertiesUsedinHVDCSystems........................................................................11
Figure3‐3 MonopolarHVDCIntertieUsingSWER...........................................................................................12
Figure3‐4 MonopolarHVDCIntertiewithReturnConductor(SWER‐capableforBackup)..........13
Figure3‐5 BipolarHVDCIntertie(SWER‐capableforBackup)..................................................................14
Figure4‐1 LowVoltageAlternatingCurrent(LVAC)Enclosure:MechanicalLayout........................22
Figure4‐2 HVDCTransformerTank:MechanicalLayout.............................................................................23
Figure4‐3 CentralResonantLinkTestSetup.....................................................................................................25
Figure4‐4 Hi–PotTestSetupforHVDCTransformer.....................................................................................25
Figure4‐5 DrySystemInverterModeTestSchematicandSetup..............................................................26
Figure4‐6 System#1HVTankandLVEnclosure............................................................................................27
Figure4‐7 System#1ShowingHVMeasurementProbes.............................................................................27
Figure5‐1 InstallingMicro‐ThermopileforGuyAnchor...............................................................................33
Figure5‐2 AssemblingthePrototypeGFRPPoleSplice................................................................................34
Figure5‐3 PrototypeGFRPPoleFoundationDuringInstallation..............................................................35
Figure5‐4 PrototypePoleattheFairbanksTestSite......................................................................................36
Figure6‐1 ComparativeInstalledCost:Overhead1‐MWHVDCandACInterties..............................38
Figure6‐2 ComparativeLife‐CycleCost:Overhead1‐MWHVDCandACInterties............................40
Figure6‐3 LocationMapforPotentialHVDCProjectSites...........................................................................41
Figure6‐4 GreensCreek–HoonahIntertieRoute...........................................................................................43
Figure6‐5 ProspectiveTransmissionRoutefromPilgrimHotSpringstoNome................................47
Page 8
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE VI
APPENDICES
APPENDIXA HVDCOVERVIEW............................................................................................................................A‐1
APPENDIXB ECONOMICANALYSIS...................................................................................................................B‐1
APPENDIXC CONCEPTUALDESIGNOFOVERHEADHVDCINTERTIELINES.................................C‐1
APPENDIXD CONCEPTUALDESIGNFORSUBMARINECABLES............................................................D‐1
APPENDIXE SWERCIRCUITSANDHVDCSYSTEMGROUNDING.........................................................E‐1
APPENDIXF HVDCPOWERCONVERTERDEVELOPMENT.....................................................................F‐1
APPENDIXG HVDCSYSTEMPROTECTION,CONTROLS,ANDCOMMUNICATIONS......................G‐1
APPENDIXH CANDIDATEHVDCSYSTEMDEMONSTRATIONPROJECTS..........................................H‐1
APPENDIXI STAKEHOLDERADVISORYGROUPINVOLVEMENTANDMEETINGS........................I‐1
APPENDIXJ BIBLIOGRAPHY..................................................................................................................................J‐1
Page 9
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE VII
ACRONYMSANDTERMINOLOGY
°F degreesFahrenheit
A,a,i amperesoramps
AC alternatingcurrent
ACEP AlaskaCenterforEnergyandPower
ACSR aluminumconductorsteelreinforced
ADNR AlaskaDepartmentofNaturalResources
AEA AlaskaEnergyAuthority
AEL&P AlaskaElectricLightandPowerCompany
AFI ArcticFoundations,Inc.
AKDOL AlaskaDepartmentofLabor
albedo Theextenttowhichanobjectdiffuselyreflectslight.
alternatingcurrent
Theformofelectricitycommonlyusedinhomesandbusinessesinwhichthecurrentandvoltageoscillateatafrequencyof60cyclespersecond.(Thefrequencyinsomenationsis50cycles.)
Alumoweld Atypeofcableusedinelectricalsystems.Eachstrandofthecableconsistsofasteelcorewithalayerofaluminumextrudedoveritduringthepullinganddrawingprocess.Thesteelcoreprovidesincreasedstrength,andthealuminumexteriorprovidesbettercorrosionprotectionandincreasedelectricalconductivity.
amperes/amps
Ameasureoftheamountofelectricalcurrentflowingthroughacircuit(atypicalhouseholdcircuitisratedfor20amperes).
AP&T AlaskaPowerandTelephoneCompany
APA AlaskaPowerAssociation
ASCE AmericanSocietyofCivilEngineers
AVEC AlaskaVillageElectricCooperative,Inc.
AVR automaticvoltagereference
bandwidth Ameasureofthedatatransfercapabilityofagivencommunicationsmethod.Unitsofbandwidthcanvarybutaregenerallybitspersecond.
BEC BethelElectricUtility
bipolar Atypeofdirectcurrentcircuitthatusestwowirestotransmitenergy.Bipolarcircuitsoperateonewire(“pole”)atapositivepotentialandthesecondpoleatanegativepotentialrelativetoground(e.g.,+/‐600,000volts).Thesecircuitsnormallyalsohaveanearthreturnpathwayoradedicatedgroundconductorthatisusedtocompensateforanyimbalanceonthetwopolesandservesasatemporaryreturnpathwayifthenegativeorpositivepoleisoutofserviceforanyreason.
BSNC BeringStraitsNativeCorporation
Page 10
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE VIII
Btu Britishthermalunit
CEA ChugachElectricAssociation,Inc.
CIGRE InternationaledesGrandsReseauxElectriques
circuit Acircuitprovidesanelectricalpathwayfromapointofenergysupply(e.g.,ageneratororbattery)toapointofenergyuse(e.g.,motor,lighting,etc.),andthenbacktothepointofsupply.Withoutacompletepathwayfromsupplytouseandback,thecircuitwillnotfunction.Thepathwaycantakemanyforms.Mostcommonly,itismadeofmetallic(copperoraluminum)wires,butitcanalsousewater,theearth,orothermaterials.Theseothermaterialsaremostoftenusedonthereturnpathwaybacktothepointofsupply,wherethevoltagedifferentialrelativetothesurroundingenvironmentislow.
conductor Atypicallymetallicwireorcablethatisdesignedandfabricatedtoconductelectricitybetweentwolocations.
converter AnelectricaldevicethatconvertselectricityfromACtoDCand/orfromDCtoAC.“Converter”isamoregeneraltermforarectifierorinverter.
CVEA CopperValleyElectricAssociation,Inc.
DC directcurrent
directcurrent Directcurrentistheformofelectricitycommonlyusedinbattery‐powereddevicessuchascars,flashlights,etc.Thecurrentdoesnotappreciablyvarywithtime.
distributionclass
Referstolower‐voltageelectricalsystems.Definitionsvary,butsystemsoperatingatorbelownominal35kilovolts(kV)aregenerallyclassifiedasdistribution‐class.MostruralAlaskaintertiesfunctionastransmissionsystems,butoperateatdistribution‐classvoltages,typically14.4kV.
earthreturn Ameansofcompletinganelectricalcircuitbyusingtheearthasareturnpathinsteadofasecondwire.Inmanynations,thisapproachisfrequentlyusedinruralareaswhere(1)thecosttoinstallasecondwireforthereturnpathisprohibitivelyhighand(2)thelackofburiedutilitiesensuresthattechnicalissueswithgroundreturnareminimized.
EHS extra‐high‐strength
EPR ethylenepropylenerubber
fiberoptics Acommunicationsmethodthatconsistsofsendingpulsesoflightdownglassfibers.
FO fiberoptics
ft‐lb foot‐pound
gal gallon(s)
GEC GustavusElectricCompany
GFRP glass‐fiber‐reinforcedpolymer
GPS GlobalPositioningSystem
GVEA GoldenValleyElectricAssociation,Inc.
Page 11
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE IX
HEA HomerElectricAssociation,Inc.
hertz Aunitofhowrapidlysomethingoscillates,rotates,orrepeats.Onehertzisequaltoonecompletecyclepersecond.AlternatingcurrentelectricalsystemsintheU.S.operateat60hertz,or60cyclespersecond.
high‐impedancegroundfault
Afaultorshortcircuitbetweenahigh‐voltagewireandground.Anexampleofahigh‐impedancegroundfaultwouldbeaconductorthatfallstothegroundwithoutbreaking,landingoniceorice‐richsoils.Thesesoilsareverypoorconductors,thuslittleornocurrentmayshortcircuitintotheground.Becausethewiredidnotbreak,itcancontinuetotransmitenergybetweentheconverters.Thisenergizedwireposesahazardtoanypeopleoranimalswhohappenuponit.
high‐voltagedirectcurrent
Directcurrentelectricityatahighvoltagerelativetothesurroundingenvironment.
HMI human‐machineinterface
hotwork Workingonelectricalequipmentwhileitisenergized.
HVDC high‐voltagedirectcurrent
IEC InternationalElectro‐technicalCommission
IEEE InstituteofElectricalandElectronicsEngineers
IGBT insulatedgatebipolartransistor
inverter AnelectricaldevicethatcanconvertDCelectricityintoACelectricity.
IPEC InsidePassageElectricCooperative
KEA KodiakElectricAssociation,Inc.
kHz kilohertz(1,000hertz)
kilowatt 1,000watts.OnekWisthepowerconsumedbyten100‐wattincandescentlightbulbs.
kilowatt‐hour Thequantityofenergyequaltoonekilowatt(kW)expendedforonehour.
KoEA KotzebueElectricAssociation,Inc.
kV kilovolt(1,000volts)
kVA kilovolt‐ampere
kW kilowatt(1,000watts)
kWh kilowatt‐hour
LDE LineDesignEngineering,Inc.
LFL linefaultlocator
LIDAR lightdetectionandranging
litzwire Anelectricalwireorcablemadeofmultipleindividuallyinsulatedstrandsofwire.LitzwireisusedinhighfrequencyACapplicationsandisdesignedtoreducepowerlossescausedbyskineffectsandproximityeffectsthatoccurathighfrequencies.
LVAC low‐voltagealternatingcurrent
Page 12
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE X
MEA MatanuskaElectricAssociation
MHRC ManitobaHVDCResearchCentre
mm2 squaremillimeters
MOD motor‐operateddisconnector
monopolar Adirectcurrentcircuitthatoperatesonelegofthecircuitatanelevatedvoltageandthereturnlegatorneargroundvoltage.Thereturnlegcanuseametallicconductoror,inthecaseofearthorseareturnsystems,canusetheearthorseatocompletethecircuit.AnHVDCSWERcircuitisonetypeofmonopolarcircuit.
ms millisecond(s)
MSB Matanuska‐SusitnaBorough
MTDC multi‐terminaldirectcurrent
MVA megavoltamperes(onemillionvoltamperes)
MW megawatt(s)(1,000kilowatts)
MWh megawatt‐hours
NCC NomeChamberofCommerce
NEA NaknekElectricAssociation,Inc.
NEC NushagakElectricCooperative,Inc.
NESC NationalElectricalSafetyCode
NJUS NomeJointUtilityService
NLP NuvistaLightandPower,Inc.
NRECA NationalRuralElectricCooperativeAssociation
NSB NorthSlopeBorough
NWAB NorthwestArcticBorough
O&M operationsandmaintenance
OED CityofOuzinkieElectricDepartment
OMR&R OperationandMaintenance,Repair,Replacement,andRehabilitation
OPGW opticalgroundwire
PCB printedcircuitboard
PCE PowerCostEqualization
PLC powerlinecarrier
PPS PrincetonPowerSystems,Inc.
PSCAD PowerSystemsComputerAidedDesign
psf poundspersquarefoot
R&D researchanddevelopment
RCA RegulatoryCommissionofAlaska
rectifier AnelectricaldevicethatcanconvertACelectricityintoDCelectricity.
Page 13
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE XI
RMS root‐mean‐square
rootmeansquare
Therootmeansquarevoltageisthemeanabsolutevoltageoveranywholenumberofwaveformoscillations.Forasinusoidalwaveform(suchasnormalACelectricity),theroot‐mean‐square(RMS)voltageisthepeakvoltagedividedbythesquarerootof2.Nominal120voltsalternatingcurrent(VAC)electricitythushasapeakvoltageofabout+/‐170voltsrelativetoground.
RUS RuralUtilitiesService(USDA)
SAG StakeholdersAdvisoryGroup
SCADA supervisorycontrolanddataacquisition
seareturn Ameansofcompletinganelectricalcircuitbyusingthesea(ormoregenerallyrivers,lakes,andotherwaterbodies)asareturnpathinsteadofasecondwire.Thisapproachisfrequentlyusedonsubmarinecableswherethecostsavingsfromnotinstallingasecondcablejustifythisapproach.Seareturncanbeusedforsingle‐phaseACcircuitsorforDCcircuits.
SEAPA SoutheastAlaskaPowerAgency
SEC SoutheastConference
single‐wireearthreturn
Anothertermforanearthreturnorseareturncircuit.Thenameemphasizesthefactthatthesetypesofcircuitsonlyrequireonewire,ascomparedwithtwoormorewiresforothertypesofcircuits.
spurandbelt Acommonmethodofclimbingutilitypoles,trees,andsimilarobjects.Specialclimbingspursarestrappedontothefeetandalargebeltisfixedaroundtheclimber'swaist.Theclimberloopsthebeltaroundthepoleanddrivesthespursintothepole.Theclimberthen“walks”upthepolewiththespurs,andhitchesthebeltalongthepoleforsupport.
steppotential Avoltagegradientthatoccursatthegroundsurfaceduetoearthreturncurrents.Ifthevoltagegradientishighenough,itcanposeahazardtopeopleorwildlifesteppinginthevicinity.
strandedenergyresources
Energyresourceslocatedinremote,distant,orotherwiseisolatedareas“stranded”fromeither(1)integrationintomodernenergyinfrastructureandsupplychainsor(2)utilizationbylocalpopulationandindustrycenters.
SWAMC SouthwestAlaskaMunicipalConference
SWER single‐wireearthreturn
transmission‐class
Referstohigher‐voltageelectricalsystems.Definitionsvary,butinAlaskaACsystemsoperatingabovenominal35kVline‐to‐groundaregenerallyclassifiedastransmission‐class.MostruralAlaskaintertiesfunctionastransmissionsystems,butareoperatedatdistribution‐classvoltages.
twistedpair Agenerictermforcommunicationscablethatusesmultipleindividuallyinsulatedwires.Eachpairofwiresistwistedtogether,hencethename.
TWMR transmissionwithmetallicconductor‐returnpath
UAF UniversityofAlaskaFairbanks
USDA U.S.DepartmentofAgriculture
Page 14
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE XII
V volt
VAC voltsalternatingcurrent
VAR volt‐amperesreactive
VDC voltsdirectcurrent
VFT variablefrequencytransformer
volt Aunitofelectricalpotential.Sometypicalvoltagesarecarbattery:12volts(DC);alkalinebattery(AAA,C,D,etc.):1.5volts(DC);householdelectricity:120volts(ACRMS).
VSC voltagesourceconverter(s)
ZAE ZarlingAeroConsulting
Page 15
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 1
1.0 INTRODUCTION
ThisreportpresentstheachievementsandfindingsofPhaseIIofthe“High‐VoltageDirectCurrent(HVDC)TransmissionSystemsforRuralAlaska”researchanddevelopment(R&D)program.
ThegoalofthisprogramistoimprovetheeconomicviabilityofAlaska’sruralcommunitiesbyprovidingmoreaffordableelectricitytransmissionalternatives.TheeffectofexcessiveenergycostscontinuestodegradethequalityoflifeinAlaska’sruralcommunitiesandplacestheseindigenouspopulationsatsevererisk.Nearly80%ofruralcommunitiesaredependentondieselfuelfortheirprimaryenergyneeds.Someofthepooresthouseholdsspent47%oftheirincomeonenergyin2008,morethanfivetimestheamountinAnchorage(CWN,2012).
Reducingthecostoflow‐power(1megawatt[MW]andless)intertiesbyusingHVDCsystemscanenableincreasedinterconnectionofruralcommunitiestoAlaska’sabundantenergyresources.HVDCintertieswillsupportmorecost‐effectivedevelopmentoflocalenergyresources,suchaswind,hydro,biomass,geothermal,hydrokinetic,gas,andcoal.
PhaseIIofthisprogramwasfundedbytheDenaliCommissionandcompletedbyPolarconsultAlaska,Inc.(Polarconsult)undercontracttotheAlaskaCenterforEnergyandPower(ACEP).ThisPhaseIIeffortandfinalreportfollowstheresultsofthePhaseIR&Dproject,completedin2009andsummarizedinPhaseI–PreliminaryDesignandFeasibilityAnalysisFinalReport(Polarconsult,2009).PhaseIofthisR&DprogramincludedevaluationofthetechnicalandeconomicfeasibilityoftheproposedHVDCsystem,includinglimitedprototypingandtestingoftheconvertertechnology.
PhaseIIoftheHVDCTransmissionSystemprogramincludeddesign,fabrication,andtestingoffull‐scaleprototypesoftheconverterandtransmissionsystemelements.ThePhaseIIeffortsinvolvedtheevaluationofdesign,efficiency,andfunctionalityoftheHVDCsystems.RuralAlaskaintertiealternativeswerealsoinvestigated,whichinvolvedcomparingHVDCtransmissionsystemstotheconventionalalternatingcurrent(AC)alternatives.ThePhaseIIfindingswereusedtofurtherdevelopconstructioncostestimatesandrefinetheeconomicanalysisofthetechnologydevelopedinPhaseI.PolarconsultistheprimecontractorandauthorofbothPhaseIandIIprojectreports.
Asaresultofongoingadvancesinpowerelectronics,small‐scaleHVDCintertiesarenowfeasible.ThisreporthasidentifiedoverheadandsubmarineHVDCtransmissionsystemsaseconomicallysuperioralternativestoconventionalACinterties.
AdditionalcostreductionscanberealizedbyintegratingHVDCsystemswithfutureexpansionofbroadbandfiber‐optictelecommunicationnetworks.ThissynergisticopportunitybetweenthetelecommunicationsandelectricindustriesisoneofseveralreasonsHVDCintertiescanhelpsurmounttheeconomicbarriersfacingAlaska’sruralcommunities.
ComparativeanalysisofHVDCtransmissionsystemswithconventionalACsystemsindicatessignificanttechnicalandeconomicadvantagesofHVDCsystems.InmanyruralAlaskaapplications,theuseofHVDCsystemswillsignificantlylowerintertiecosts.
Basedonthefavorablefindings,PolarconsultrecommendscontinuedworkonthisprojectthroughPhaseIIIworkactivities,includingdemonstrationoftheHVDCsystemonanAlaskautilitysystem.
Page 16
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 2
1.1 REPORTORGANIZATION
PhaseIIofthisprojectaddressesawiderangeoftechnicaldisciplinesandsubjectmaterial.Forbrevity,thebodyofthisreportfocusesonthekeyfindingsandconclusionsthathaveresultedfromthiswork.In‐depthinformationpertainingtospecifictopicsisincludedinthereport’sappendices.
Thisreportisorganizedasfollows:
● TheExecutiveSummaryandtheAcronymsandDefinitionssectionsareincludedatthebeginning.
● Section1.0introducesthereport.
● Section2.0providesbackgroundinformationonAlaska’sruralenergyissuesandabriefexplanationofthestakeholders’rolesinthisphaseoftheproject.
● Section3.0isadescriptionoftheHVDCtransmissionsystem,whichincludesacomparisonofACandHVDCtransmission,overheadintertiealternatives,andsubmarinecableintertiealternatives.
● Section4.0discussesHVDCconverterstations.
● Section5.0evaluatesthedesignconceptsforoverheadinterties.
● Section6.0containstheeconomicevaluationofPhaseII.
● Section7.0providestheconclusionsandrecommendationsforthePhaseIIprototypingandtestingstudy.
Inaddition,thisreportcontainsthefollowingappendices,whichincludereportsgeneratedbyPolarconsult’ssubcontractorsforthisprojectasattachments:
● AppendixA HVDCOverview
● AppendixB EconomicAnalysis
● AppendixC ConceptualDesignofOverheadHVDCIntertieLines
● AppendixD ConceptualDesignforSubmarineCables
● AppendixE SWERCircuitsandHVDCSystemGrounding
● AppendixF HVDCPowerConverterDevelopment
● AppendixG HVDCSystemProtection,Controls,andCommunications
● AppendixH CandidateHVDCSystemDemonstrationProjects
● AppendixI StakeholderAdvisoryGroupInvolvementandMeetings
● AppendixJ Bibliography
Page 17
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 3
1.2 ACKNOWLEDGEMENTS
Polarconsultacknowledgesandappreciatesthesupportandcontributionsofthemanyindividualsandentitiesthathaveparticipatedinthisproject.Theirsupport,insights,experience,andtechnicalanalysis remain invaluable to the continuing effort to bring lower‐costHVDC intertie systems toAlaskans.
MembersoftheteaminvolvedinthesecondphaseofHVDCintertiedevelopmentinclude:
● DenaliCommission(FundingAgency)
● ACEP(GrantManagement,EconomicAnalysis,Strategy)
● Polarconsult(ProjectManagement,StrategicVision,Design)
● PrincetonPowerSystems,Inc.(PPS)(ConverterDevelopment)
● UniversityofAlaskaFairbanks(UAF)/Dr.RichardWies(UAFQualityControlandTechnicalReview)
● AlaskaVillageElectricCooperative,Inc.(AVEC)(AlaskaIntegration/Practicality)
● StakeholdersAdvisoryGroup(Practicality/IndustryAcceptance)
● ManitobaHVDCResearchCentre(HVDCExpert)
● LineDesignEngineering(StructuralandCodeExpert)
● GolderAssociates(GeotechnicalExpert)
● Almita,Inc.(FoundationSupplier)
● ArcticFoundations,Inc.(AFI)(FoundationSupplier)
● ZarlingAeroConsulting(ZAE)(ThermalSoilsAnalysis)
● STG,Inc.(RuralIntertieContractor)
● Cabletricity,Inc.(SubmarineCable/HVDCExpert)
Inaddition,theStakeholdersAdvisoryGroup(SAG)membershaveplayedaninstrumentalroleinthisprogrambycontributingtheirtimeandyearsofexperience.TheSAGwaschairedbytheDenaliCommissionandfacilitatedbyACEP.SAGmembersinclude:
● AlaskaDepartmentofLabor(AKDOL)
● AlaskaEnergyAuthority(AEA)
● AlaskaPower&TelephoneCompany(AP&T)
● AlaskaPowerAssociation(APA)
● AVEC
● BeringStraitsNativeCorporation(BSNC)
● BethelElectricUtility(BEC)
● CopperValleyElectricAssociation,Inc.(CVEA)
● GoldenValleyElectricAssociation,Inc.(GVEA)
● HomerElectricAssociation,Inc.(HEA)
● InsidePassageElectricCooperative(IPEC)
● InstituteofNorthernEngineering(INE),UAF
Page 18
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 4
● KodiakElectricAssociation,Inc.(KEA)
● KotzebueElectricAssociation,Inc.(KoEA)
● MatanuskaElectricAssociation(MEA)
● NaknekElectricAssociation,Inc.(NEA)
● NationalRuralElectricCooperativeAssociation(NRECA)
● NomeChamberofCommerce(NCC)
● NomeJointUtilityService(NJUS)
● NorthSlopeBorough(NSB)
● NorthwestArcticBorough(NWAB)
● NushagakElectricAssociation
● NuvistaLightandPower,Inc.(NLP)
● SoutheastConference(SEC)
● SouthwestAlaskaMunicipalConference(SWAMC)
● U.S.DepartmentofAgriculture(USDA)RuralUtilitiesService(RUS)
● UAF
1.3 DISCLAIMER
ThisreportwaspreparedbyPolarconsultsolelyfortheUAF.TheUAFhastherighttoreproduce,use,andrelyuponthisreportforpurposesrelatedtoinvestigatingthe“HVDCTransmissionSystemforRuralAlaskanApplications,”including,withoutlimitation,therighttodeliverthisreporttoregulatoryauthoritiesinsupportof,orinresponseto,regulatoryinquiriesandproceedings.ForthepurposesofthisDisclaimer,allpartiesotherthanPolarconsultandtheUAFare“thirdparties.”NeitherPolarconsultnortheUAFrepresent,guarantee,orwarranttoanythirdparty,expresslyorbyimplication,theaccuracy,suitability,reliability,completeness,relevance,usefulness,timeliness,fitness,oravailabilityofthisreportforanypurposeortheintellectualorotherpropertyrightsofanypersonorpartyinthisreport.
Thirdpartiesshallnotuseanyinformation,product,orprocessdisclosed,described,orrecommendedinthisreportandshallnotrelyuponanyinformation,statement,orrecommendationcontainedinthisreport.Shouldanythirdpartyuseorrelyuponanyinformation,statement,recommendation,product,orprocessdisclosed,contained,described,orrecommendedinthisreport,theydosoentirelyattheirownrisk.Tothemaximumextentpermittedbyapplicablelaw,innoeventshallPolarconsultortheUAFacceptanyliabilityofanykindarisinginanywayoutoftheuseorreliancebyanythirdpartyuponanyinformation,statement,recommendation,product,orprocessdisclosed,contained,described,orrecommendedinthisreport.
1.4 COPYRIGHTNOTICE
ThisreportiscopyrightprotectedbyPolarconsultandmaynotbereproducedinwholeorpartwithoutthepriorwrittenconsentofPolarconsult.
Page 19
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 5
2.0 BACKGROUND
Energycoststhroughoutmostofrural1Alaskaaresignificantlyhigherthaninthestate’surbanareas.Overthepastdecade,ruralenergycostshaveescalateddramatically,tothepointwherelifeinmanyruralAlaskancommunitiesisinastateofeconomicperil.TheprimaryreasonsforthesehighenergycostsisruralAlaska’sdependenceondieselfuelforpowergenerationandheating,thelackofeconomiesofscaleinruralcommunities,andthetransportationchallengescommoninruralAlaska.
FormostruralAlaskancommunities,adiesel‐electricplantisthepowergenerationresourceofchoicesincetheseplantsandtheirsupportinginfrastructuresuchasbulkfuelfacilitiesarereadilyadaptedtotheneedsofrurallocalities.However,generatingelectricitywithdieselfuelisexpensiveduetothesecommunities’smallscaleandgeographicisolation.Consequently,ruralAlaskahassignificantlyhigherenergycostscomparedtocommunitiesinorconnectedwithAlaska’surbancenters.ThehighcostofruralenergynegativelyaffectboththequalityandsustainabilityoflifeinruralAlaska.
Manypowergenerationcostsarebeyondacommunity’scontrol.Thefuelpricefortheseplantsisdeterminedbyanincreasinglyvolatileglobalenergymarket.Inaddition,asubstantialcomponentofthefuelcostistransportation.Inrecentyears,thelimitedshippinganddeliverywindowscausedbyseasonaliceandlowwaterconditionsinmanypartsofthestatehaveresultedinvillagespayingrecordpricesforfuel.Interiorcommunities,locatedneartheupperlimitsofnavigablewaterwaysandthussusceptibletolowwaterconditions,paidasmuchas$11pergallonin2010(DCRA,2010).Severalruralcommunitiesfrequentlyflyinfuelduetoalackofreliablebargeaccessorservice.
Alternativestodieselgenerationoftenexistintheformoflocalenergyresourcessuchashydro,wind,geothermal,tidal,solar,gas,coal,andbiomass.However,manyofthese“strandedenergyresources”arenoteconomicallyviableduetothecostoftheconventionalACelectrictransmissionsystemsrequiredtointerconnectthemandtheprohibitivelyhighcosttodeveloptheselocalenergyresourcestoservesmallloads.HVDCintertiescanhelpsurmountbothofthesebarriersbyloweringthecosttoreachstrandedenergyresourcesandbyreducingthecosttointerconnectcommunities(ACEP,2012).
AlthoughcommercialHVDCtransmissiontechnologyhasbeenavailableforover50years,ithasbeenlimitedtolarge‐scaletransmissionoftenstothousandsofMWsofpower.ThesesystemsarefartoolargeandexpensivetousefortheinterconnectionofAlaska’sruralcommunities,whichtypicallyhaveloadsmeasuredinthehundredstothousandsofkilowatts(kWs).Currently,nocommerciallyavailableHVDCconvertersystemexiststhatissuitableforinterconnectingtheseruralcommunities.However,innovativetechnologiesinthepowerelectronicsindustryhavemadethedevelopmentoflow‐power,cost‐effectiveconvertersfeasible.
PolarconsulthasinvestigatedalternativestoACintertiesandfoundthatinmanyapplications,HVDCtransmissionsystemsusinginnovativepowerconversiontechnologiesofferthemosteconomicalsolutiontointerconnectwithstrandedenergyresources.Further,thereplacementofaconventionaloverheadACthree‐orfour‐wiretransmissionlinewithaone‐ortwo‐wireHVDC
1 RuralAlaskaforthepurposesofthisreportreferstoisolatedcommunitiesoffthemainroadsystemthathavehigh
energycostsduetotheirlocation,size,orotherfactors.
Page 20
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 6
transmissionlinehassignificantcostadvantages.Thechangeinoverheadinfrastructureresultsinreducedstructuralloads,allowingfewersupportstructurespermileoftransmissionline.ThedecreaseinmaterialsandconstructiontimeisoneofseveralreasonsthatoverheadHVDCintertiesarelesscostlythanACinterties.SubmarineandburiedHVDCintertiescanalsobelesscostlythantheirACalternatives.
2.1 PROGRAMOVERVIEW
TheHVDCdevelopmenteffortconsistsofthefollowingphases:
PhaseI–PreliminaryDesignandFeasibilityAnalysis(2008‐2009)
DuringPhaseI,PolarconsultevaluatedthetechnicalandeconomicfeasibilityoftheproposedHVDCsystem.TasksincludeddefiningtheHVDCsystem’spreliminarydesignparameters,definingdesignconsiderationsforthetransmissionandconvertercomponents,andestimatingcostsforthesesystems.PhaseIalsoincludedlimitedprototypingandsuccessfultestingoftheconvertertechnology.
PhaseII–PrototypingandTesting(2010‐2012)
PhaseIIincludedconstructionandtestingoffull‐scaleprototypesofthetransmissionandconvertersystems.ThiseffortvalidatedthedesignofthesesystemsandvalidatedthefeasibilityoftheconstructionmethodsnecessarytomakethesystemasuccessinruralAlaskaapplications.TheinformationfromPhaseIItestingwasusedtorefinetheconstructionmethodsanddevelopcostestimatesusedintheeconomicanalysisofthetechnologydescribedinthisreport.ThisreportisthefinaldeliverableforPhaseII.
PhaseIII–DemonstrationProject(Proposed)
PhaseIIIwillincludefulltestingoftheconvertersystem,includingthemanufacturerandthird‐partyfunctional,compliance,andperformancetestingneededtomovetheconvertertechnologyfromadvancedprototypestoacommercialproduct.PhaseIIIwillalsoincludeafull‐scalefielddemonstrationoftheHVDCtechnologyonautilitysysteminAlaska.Thespecificprojectdetailsaredependantonthecandidatelocationselectedfortheintertie.PhaseIIIisintendedtobethefinalproof‐of‐conceptproject,tobefollowedbycommercialdeploymentofthesystem.
Page 21
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 7
2.2 STAKEHOLDERADVICE
ThisprojectseekstodevelopahighlyinnovativepowertransmissiontechnologyfordeploymentinruralAlaskaapplications.Becausemanyaspectsofthissystemmarkadeparturefromacceptedpracticeinruralpowersystems,widespreadindustryunderstanding,aswellasacceptance,ofthistechnologyisconsideredcriticaltothesuccessofthiseffort.Additionally,theoverviewandfeedbackofindustryisconsideredcriticaltothesuccessfuldevelopmentoftheinnovativesystemsneededforthisHVDCtechnology.
TheDenaliCommissionandACEPrecognizedthatthebestmeanstoachievethisunderstanding,acceptance,andfeedbackwouldbetodirectlyengagethestakeholdersandend‐usersoftheproposedsysteminthedevelopmentstagesofthetechnology.Tothisend,aSAGwasformedaspartofthePhaseIIefforttofamiliarizeandfacilitatefeedbackfromindustryleadersonthedevelopmentofthissystem.
TheSAGisanadvisorybodycomprisedofrepresentativesofAlaska’sruralelectricutilityindustryandrelatedprofessionals.ThepurposeoftheSAGistoprovidecomments,feedback,review,andrecommendationstotheHVDCproject.TheSAGheldthefollowingthreemeetingsoverthecourseoftheproject:
● SAGMeeting#1–Fairbanks,Alaska‐‐April27,2010;
● SAGMeeting#2–Anchorage,Alaska–January14,2011;and
● SAGMeeting#3–Anchorage,Alaska–October25,2011.
Severaladditionaloutreachactivitiesoccurredoverthecourseoftheproject.Theseincluded:
● SoutheastConferenceMid‐SessionSummit–Juneau,Alaska(March2,2010);
● EmergingEnergyTechnologyForum–Juneau,Alaska(February14,2011);
● Brown‐BagWorkSession–Anchorage,Alaska(August29,2011);and
● HVDCConverterDemonstration–Lawrenceville,NewJersey(November14,2011).
AppendixIprovidesthefollowingdetailedinformationregardingSAGmeetingsanddiscussions:
● ListofSAGmembers;
● SummaryofSAGroleandpolicies;
● SummaryofkeyinformalcorrespondencebetweenSAGmembersandPolarconsultoverthecourseoftheproject;
● HandoutsfromthethreeSAGmeetings;and
● Handoutsfromothermeetingsandoutreachactivitiesconductedoverthecourseoftheproject.
AdditionaldetailsassociatedwiththeSAGmeetingsandproceedingsarepresentedinAppendixI.TranscriptsoftheSAGmeetingsareavailableuponrequest.
Page 22
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 8
3.0 HVDCTRANSMISSIONSYSTEMDESCRIPTION
HVDCtransmissionsystemscantakeonawidevarietyofconfigurations.Thissectiondescribesthoseconfigurationsrelevanttolow‐powerHVDCapplicationsinruralAlaskaapplications.
● Section3.1providesageneraloverviewofthehistoryofHVDCpowertransmissionandthemajorcomponentsofanHVDCtransmissionsystem.
● Section3.2providesageneraloverviewofthedifferentconfigurationsofHVDCsystemsforpowertransmissionapplications.
● Section3.3providesacomparisonofHVDCandACpowertransmissionalternatives.
● Section3.4providesadescriptionofoverheadlinealternativesforACandHVDCapplications.
● Section3.5providesadescriptionofsubmarinecablelinealternativesforACandHVDCapplications.
3.1 HVDCBACKGROUND
ThomasEdisonpioneeredthefirstutility‐scaleapplicationofelectricpowerinNewYorkCityinthe1880swithadirectcurrent(DC)electricutilitysystem.Concurrently,GeorgeWestinghousewasmarketinganACelectricutilitysysteminventedbyNikolaTesla.ACwasbettersuitedtosteppingupvoltages,whichisvitaltoeconomicalelectrictransmissionacrosstownandbetweencities.Bythe1890s,Westinghouse’sACsystemhadprevailedoverEdison'sDCsystem,andACbecametheindustrystandard.
Inthe1950s,technologicaladvancesenabledDCsystemstoreentertheelectricutilityindustry.Withthecommercializationofthemercuryarc‐valve,voltagetransformationofDCandconversionbetweenDCandACelectricityonalargescalebecamecost‐effective.ThisallowedutilitiestobeginusingHVDCtransmissionlinksintheirsystems.
BecauseofthehighcapitalcostoftheseearlyHVDCconverters,utilityusageofHVDCremainedlimitedtotransmissionfunctions.ACremainedtheindustrystandardforelectricitygeneration,distribution,andconsumption.
Today,HVDCconvertertechnologyhasadvancedtousehighefficiencysolid‐statehardware,andHVDClinksareusedforelectricaltransmissionthroughouttheworld.Thesmallestavailableutility‐gradeHVDCsystemsaredesignedtotransmitapproximately50MW2.Asaresult,thecurrentcommerciallyavailableHVDCconvertersareoversizedandprohibitivelyexpensiveforAlaskanintertiesthattypicallyrequirethetransferoflessthan1MW.Figure3‐1isanimageofalargeHVDCstation.
2“HVDCLite,”distributedbyABB,isoneexampleofthesmallerutility‐gradeHVDCsystems.
Page 23
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 9
HVDCtransmissionsystemsincludethefollowingmajorcomponents:
● HVDCConverterStations.EachconnectionpointbetweentheHVDCtransmissionlineandaloadcenterrequiresanHVDCconverterstation.TheconverterstationconvertstheHVDCelectricityintoACelectricitythatcanbemovedthroughalocalpowergridandused.Theconverterstationincludesthepowerconverters,groundingstations,communicationsandcontrolsystems,andprotectiveequipmentasrequiredbytheparticularsystemdesignrequirements.ThepowerconvertersarediscussedinAppendixF.ThegroundingstationsarediscussedinAppendixE.
● HVDCTransmissionLine.TheHVDCtransmissionlineistheoverheadwire,submarinecable,undergroundcable,orcombinationofthesethatconnectstheconverterstationstogetherandformsthetransmissioncircuit.Theconfigurationanddesignofthetransmissionlinewilldependonlocalconditionsandsystemrequirements.OverheadtransmissionlineconceptsarediscussedinAppendixC.SubmarinecabletransmissionlineconceptsarediscussedinAppendixD.
● ControlsandCommunications.TheHVDCtransmissionsystemrequiresameansofcommunicatingbetweentheconverterstationsandthecontrolthesystem.ThesimplestcontrolandcommunicationschemewouldusetheDClinevoltageasacontrolsignal.Thiswouldbesuitableforapoint‐to‐pointHVDCsystemthatfeedspowerinonedirection.Powerreversalovertheintertiewouldbepossiblewithmanualintervention.ControlandcommunicationoptionsforHVDCsystemsarediscussedinAppendixG.
Figure 3-1 Typical Large HVDC Station
5,000MW+/‐800kVHVDCYunnan‐GuangdongConverterStation.(TDW,2012)
Page 24
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 10
3.2 HVDCSYSTEMCONFIGURATIONS
ThevarioussystemconfigurationsforHVDCcanbeclassifiedintothreedifferentcategories,withseveraloptionswithineachcategory.Thethreecategoriesandmajoroptionsareshownbelow.Eachcategoryisdescribedinmoredetailinthefollowingsections.
TypesofHVDCUtilityPowerSystems
HVDCApplication‐HowtheHVDCtechnologyisused:
● Point‐to‐PointDCPowerTransmission
● MultiterminalDirectCurrent(MTDC)PowerTransmission
HVDCCircuit‐Howtheelectricityistransported:
● MonopolarwithSingle‐WireEarthReturn(SWER)
● MonopolarwithMetallicReturn
● Bipolar
IntertieType‐Howthewirestransportingtheelectricityareconfigured:
● Overhead
● Submarine
● Underground
3.2.1 HVDCSystemApplications
TherearethreebasicapplicationsofHVDCtechnologyintoday’selectricutilityindustry.Theseare:
● Point‐to‐pointpowertransmission.ThemajorityofHVDCsystemsinusetodayarepoint‐to‐pointtransmissionsystems.Thesetransportbulkenergy(100sor1,000sofMWs)overlongdistances(100sor1,000sofmiles)moreefficientlythanACtransmissionsystems.
Point‐to‐pointnetworkswillbeasignificantapplicationforthelow‐powerHVDCtechnologybeingdevelopedwiththisproject.
● Multiterminalpowertransmission.MTDCnetworksareamoreflexibleandcomplicatedapplicationofHVDCtransmissiontechnology.Insteadofthetwoterminalsinaconventionalpoint‐to‐pointHVDCsystem,MTDCsystemshavemorethantwoterminalsandcanroutepowertoorfromtheseterminalsasneeded.MTDCsystemsarecurrentlyreceivingsignificantindustryinterestastechnologyevolvestohandlethesemorecomplicatedsystemsandregionalgridsdemandthesuperiorperformanceandenhancedcapabilitiesthatMTDCsystemsofferoverACtransmissionnetworksforcertainapplications.Thereareahandfuloflarge‐scaleMTDCsystemsplannedorinoperation.ExamplesincludetheQuebec–NewEnglandMTDCsystemandtheSardinia–Corsica–ItalyMTDCsystem.
ManyregionalenergysolutionsinruralAlaskausingHVDCwillbeintheformofMTDCnetworks.ThepowerconvertersdevelopedforthisprojectcansupportMTDCoperation,providedsuitablecontrolsystemsandprotectiveequipmentarepresent.MTDCsystemsandcontrolconsiderationsarediscussedingreaterdetailinAppendixG.
Atthemostabstractlevel,anelectricalcircuitrequirestwocurrentpathways,normallymetalwires.Onewiregoesfromthepowersupplytotheload,andasecondwiregoesfromtheloadback
Page 25
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 11
INCREASING COST AND COMPLEXITY
1. Monopolar with earth return (SWER) 2. Monopolar with return conductor 3. Bipolar
tothepowersupply.Bothsingle‐phaseACandDCcircuitsrelyonthisbasicconfiguration.Thewirefromthepowersupplytotheloadisusuallyatanincreasedvoltagerelativetoground,andsoitisinsulatedforsafetyandtopreventshortcircuits.Thewirefromtheloadbacktothepowersupplyisusuallyatamuchlowervoltagerelativetogroundandisusually,butnotalways,insulated.
TherearethreetypesofHVDCcircuitsinusearoundtheworld.Eachofthesecircuitsmayutilizeoverheadwires,undergroundcables,submarinecables,oracombinationofthese.ThesethreecircuitsarelistedonFigure3‐2anddescribedonthefollowingpages.
Figure 3-2 Three Types of Interties Used in HVDC Systems
MorecomplexHVDCcircuitconfigurationsnormallyincorporateelementsofthesimplercircuitsforefficiency,reliability,redundancy,and/orsafety.Forexample,allbipolarHVDCsystemsincludeearthelectrodesandsometimesagroundconductorsotheycanoperateeitherpoleinmonopolarormonopolarSWERmodeduringmaintenanceoremergencies.Generally,themorecomplexbipolarcircuitconfigurationsareusedforlarge,importantintertieswheretheincreasedreliability,efficiency,andpowerthroughputcapabilityjustifythehighercostofthesesystems.
3.2.1.1 SingleWireEarthReturn(SWER)CircuitsSWERcircuitsusethesubsurfacegeologyasareturncurrentpathway.Seareturncircuitsaresimilartoearthreturncircuits.Theonlydifferenceisthatthesea,oranywaterbody,isusedasthepredominantreturncurrentpathway.Parallelpathways,suchastheseabed,arealsoavailableforcurrentflow.TheprimaryadvantagesofferedbySWERcircuitsinclude:
● Lowercosts(eliminatethesecondconductor).
● Higherefficiency(lowerelectricallosses).
TheprimaryconcernsassociatedwithSWERcircuitsinclude:
● Avoidingaccelerated“inducedcurrent”corrosionofburiedmetallicobjects.
● Aswithallelectricalsystems,safety.SWERcircuitsarewidelyusedforutilitytransmissionanddistributionofelectricityallovertheworld.NumerousHVDCintertiesareSWERcircuits,consistingofasinglehigh‐voltagecableandanearthorseareturntocompletethetransmissioncircuit.ManyoftheseareinstalledinclimatesandconditionssimilartoAlaska,notablyinScandinavia.Inmanynations,single‐phaseACSWERcircuitsareacceptedpracticeandareindustrystandardforservingruralareas.
Page 26
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 12
Twosingle‐phaseACSWERcircuitshavebeensuccessfullybuiltandoperatedinAlaska.TheseACSWERcircuitsdemonstratethatSWERisaproven,beneficial,andappropriatetechnologyforruralAlaskatransmissionapplications.
3.2.1.2 MonopolarHVDCCircuitUsingSWER
AmonopolarHVDCintertieusingSWER(seeFigure3‐3)forthereturnpathwaywillgenerallybethelowest‐costalternativeforHVDCpowertransmissioninruralAlaskaapplications.Thiscircuitconfigurationwillconsistofthefollowingmajorcomponents:
● AC/DCconvertermoduleinthegeneratingvillage.
● High‐voltageconductor.Thiscanbeanoverheadline,buriedcable,orsubmarinecable.
● DC/ACconverterinthereceivingvillage.
● Groundingelectrodesinbothvillagestocompletetheintertiecircuitusingearthreturn.
Figure 3-3 Monopolar HVDC Intertie Using SWER
TherearenumerousexamplesofmonopolarHVDCintertiesusingSWERcircuits.The500‐MWsubmarineHVDClinkcompletedbetweenVictoriaandTasmania,Australia,in2006isoneexampleofarecentlyconstructedSWERHVDCsystem.BipolarandmonopolarHVDCcircuitsarenormallydesignedtooperateinamonopolarSWERconfigurationwhenneededtomaximizesystemreliability.
Page 27
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 13
3.2.1.3 MonopolarHVDCCircuitwithReturnConductor
AmonopolarHVDCintertiewithareturnconductor(seeFigure3‐4)issimilartoamonopolarSWERHVDCintertie.Theprimarydifferenceisthattheearthreturnisreplacedwithadedicatedreturnconductortominimizeearthcurrentsinducedbytheintertie.Often,suchintertieswillstillhavetheearthelectrodesnecessarytooperateinSWERmodeandwilloperateinSWERmodeduringmaintenanceoremergencysituations.ThisHVDCcircuitconfigurationincludesthefollowingmajorcomponents:
● AC/DCconvertermoduleinthegeneratingvillage.
● High‐voltageconductor.Thiscanbeanoverheadline,buriedcable,orsubmarinecable.
● DC/ACconverterinthereceivingvillage.
● Returnconductor.Thiscanbeanunder‐builtlineonthehigh‐voltagepoles,aseparatecable,orincorporatedintothesamecableasthehigh‐voltageconductor,suchasaconcentricneutralonanACcable.
● Groundingelectrodesinbothvillages.Thesewillnotnormallybeusedtocompletetheintertiecircuit,buttheywillbeusedduringmaintenanceoremergencies.
MonopolarreturnconductorsarewarrantedinareaswhereaSWERcircuitisnotviableordesirable.Generally,thisisduetotheriskofinducingcorrosioninburiedmetallicutilities.Thelackofsuitablegroundconditionsforeconomicalearthelectrodeswouldalsowarrantuseofareturnconductor.Usinganreturnconductorwiththesameelectricalresistanceasthehigh‐voltageconductorwillnearlydoubletheconductorlossesrelativetoaSWERtransmissioncircuit.
Figure 3-4 Monopolar HVDC Intertie with Return Conductor (SWER-capable for Backup)
Page 28
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 14
3.2.1.4 BipolarHVDCCircuit
AbipolarHVDCintertie(seeFigure3‐5)isgenerallythemostcostlyandmostreliableHVDCcircuitconfiguration.Itemploystwoparallelhigh‐voltageconductors,oneoperatedatpositivevoltageandthesecondatnegativevoltage.Thesystemrequirestwoconvertersateachendoftheintertie(fourtotal),comparedtooneconverterperendformonopolarcircuits(twototal).Thus,thebipolarHVDCconfigurationincludesthesemajorcomponents:
● TwoAC/DCconvertermodulesinthegeneratingvillage.One(+)andone(–).
● Twohigh‐voltageconductors.Thesecouldbeoverheadlines,buriedcables,orsubmarinecables.
● Athirdneutralconductortocarryanycurrentduetominorimbalancebetweenthepowertransmissionlevelsonthepositiveandnegativepoles.Somebipolarsystemsdonothaveaneutralconductorandinsteadrelyonthegroundingelectrodestobalancethepoles.
● TwoDC/ACconvertersinthereceivingvillage.One(+)andone(–).
● Groundingelectrodesinbothvillages.Thesewillnotnormallybeusedtocompletetheintertiecircuit,buttheywillbeusedtobalancethesystemandforSWERoperationduringmaintenanceoremergencies.
TheadditionalcostsofabipolarHVDCintertiearelargelyduetotheadditionalconvertersandthesecondhigh‐voltageconductor.AbipolarHVDCintertiewillberoughlytwiceascostlyasamonopolarHVDCintertie,butwithtwicethecapacityandincreasedreliability.
Theprincipaladvantageofabipolarintertiecomparedtoamonopolarintertieisincreasedreliability.Ifsomethingbreaksononeofthetwopoles,theotherpolecanbeoperatedasamonopolarintertie.Thiswillreducethepowertransfercapability,buttheintertiecancontinuetofunction.
FormanyruralAlaskaapplications,theadditionalcostofbipolarcircuitsisnotjustified.Operatingbackupdieselgeneratorsinvillageswouldbemorecost‐effectivethanconstructingabipolarHVDCintertie.
Figure 3-5 Bipolar HVDC Intertie (SWER-capable for Backup)
Page 29
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 15
3.2.2 HVDCIntertieTypes
HVDCintertiescanbebuiltusingoverheadwires,submarinecables,orundergroundcables.Combinationsofthesecanbeusedforasingleintertie.OverheadwireintertieoptionsarediscussedinSection3.4andAppendixC.SubmarinecableintertieoptionsarediscussedinSection3.5andAppendixD.UndergroundcableoptionsarediscussedinAppendixG.
Page 30
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 16
3.3 COMPARISONOFACTOHVDCTRANSMISSION
ThefollowingabbreviatedcomparisonispresentedtoillustratewhenanHVDCintertieisanticipatedtobeagoodalternativetoacomparableACintertieinruralAlaskaapplications.AmoredetailedcomparisonispresentedinAppendicesAandB.
HVDCAdvantages:
● Lowerper‐mileoverheadtransmissionlinecostthanAClines;
● Abilitytouseundergroundorsubmarinecablesforlongdistances;
● Bettercompatibilitywithmigratorybirdsduetofeweroverheadconductors(1or2wiresinsteadof3or4wires);
● Asynchronousconnection;and
● Lowerper‐mileconductorenergylosses.
HVDCDisadvantages:
● AnHVDCconverterismoreexpensive,requiresmoremaintenance,andislessreliablethanacomparableACtransformer;
● Convertercostsareabarriertoservingloadsalongthetransmissionlineroute;
● UnconventionaltechnologyandlimitedequipmentsupplierscomparedtoAC;
● HVDCconvertersgenerallyhavehigherenergylossesthanacomparableACtransformer;and
● HVDCintertiesmayhavefewerfundingopportunitiesthanconventionalAClinesbecausetheyareuncommon.
Implications:
● Ifanintertiemustemploylong‐distancesubmarineorburiedcables,HVDCoffersatechnicallysuperiorsolutiontoAC.ACcableintertiesarenottechnicallyfeasibleforlong‐distancetransmissionsystems.
● Wherebothsystemsaretechnicallyfeasible,thedecisionislargelyeconomic.AnHVDCintertiewillhavehigherterminalcostsandlowerper‐milecosts.Accordingly,anACintertieismorecost‐effectiveforshortinterties,andHVDCismorecost‐effectiveforlonginterties.Thelongertheintertie,thegreaterthecostsavingsofanHVDCversusACsystem.Theeconomiccrossoverpointisprojectspecificbutforthescaleofintertiesunderconsiderationinthisreport,itwillgenerallyoccuratadistanceof6and31miles.
● SincetheHVDCconvertersdevelopedunderthisprogramusenewtechnology,andbecauseitrepresentsadeparturefromconventionalACtransmissionsystems,substantialsavingswillbeafactorinencouragingutilitiestoadoptthistechnologyinlieuofprovenbutmorecostlyintertiesolutions.
● MostACintertiesareoverheadandmaynotbeenvironmentallyacceptableinmanypartsofAlaska.HVDCintertiesareeitherburiedorhavefewerwiresandstructuresandmaybemoreacceptablewithinrefugesandothersensitiveareas.
Page 31
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 17
3.4 OVERHEADINTERTIEALTERNATIVES
3.4.1 ConventionalACInterties
Thetypicalcostforconstructingaconventionaloverheaddistribution‐classACintertieinruralAlaskacanrangefromaslittleas$100,000permileinareaswithgoodlogisticsupportandtransportationinfrastructure(roadsystem,southeast)toover$600,000permile3inruralpartsofthestatewithchallenginglogisticsandlittleornotransportationinfrastructure(remoteinterior,northwest,orYukon‐Kuskokwimdeltaregions).Becauseofthisprohibitiveexpense,relativelyfewruralintertieshavebeenbuilt.
ThehighcostofruraloverheadACintertiesistheresultofseveralfactors.TwosignificantcostcontributorscommontomanyAlaskanintertieprojectsarelogisticsandfoundations.ACsystemsrelyonmulti‐wiretransmissionlines;thisleadstohighmaterialscostsandhighloadsplacedonstructuresandfoundations.ThestructuresneededtosupportthemultipleaerialwiresofanACsystemarecostly.TheresultingACintertieusuallyhasshortspans,250to400feetbeingtypical,thusresultinginmanytransmissioncomponentssuchaspoles,hardware,wire,andfoundationsthatmustbepurchased,shipped,installed,andmaintained.
Whenthecostsofshipping,geotechnicalconditions,constructionfactors,logisticsandenvironmentalrequirementsareallfactoredin,conventionalACconstructionoftenresultsinaprohibitivelyexpensiveintertie.Asaresult,manyruralcommunitiesaredeniedtheopportunitytobenefitfrominterconnectiontoeachotherorlocalenergyresources.
3.4.2 HVDCTransmissionInterties
PolarconsulthasinvestigatedalternativestoACintertiesandfoundthatinmanyapplications,HVDCtransmissionsystemsofferthemosteconomicalsolution.
ReplacingaconventionaloverheadACthree‐orfour‐wiretransmissionlinewithaone‐ortwo‐wireHVDCtransmissionlinehassignificantcostadvantages.Thechangeinoverheadinfrastructureresultsinreducedstructuralloadsthusallowingfewersupportstructurespermileoftransmissionline.ThedecreaseinmaterialsandconstructiontimeistheprimaryreasonoverheadHVDCintertiesaremoreeconomicallyviablethanACinterties.
AmonopolarHVDCintertiedesignedasaSWERcircuitneedsonlyasinglewirealoft,whichsignificantlyreducestheloadscomparedwithathree‐orfour‐wireACintertie.Usingasinglewireprofoundlysimplifiesthetransmissionlinedesign,whichtranslatestosignificantcostsavingscomparedwithanACline.
BecauseSWERcircuitsinduceareturncurrentintheearth,theyrequirespecialattentioninthedesignandplanningphasetoavoidadverseeffectsfromthisearthcurrent.Theprimaryconcernsare(1)thesteppotential4intheimmediatevicinityofthegroundingstationsand(2)acceleratedcorrosionofburiedmetallicobjectsinthevicinityofthereturncurrentpathwaysthroughtheearth.
3SeeSectionB.6.1inAppendixBforcostbasisinformation.4Avoltagegradientthatoccursatthegroundsurfaceduetoearthreturncurrents.Ifthevoltagegradientishighenough,itcanposeahazardtopeopleorwildlifesteppinginthevicinity.
Page 32
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 18
InmostruralAlaskalocalities,theseconcernscanbereadilyaddressedthroughproperplanningandsystemdesign.
Becauseofthesespecialfactors,SWERcircuitsarenotallowedbytheNationalElectricalSafetyCode(NESC),whichistheapplicablecodeforelectricutilitytransmissionanddistributionsystems.PolarconsulthasdiscussedthisHVDCsystemandconceptindetailwiththestatecodeauthorityandfindsthatSWERcircuitscanbeapprovedonaproject‐specificbasisbyissuanceofacodewaiver.ThereisprecedentforcodewaiversbeingissuedforSWERsystemsinAlaska.TheuseofSWERcircuitsisdiscussedfurtherinAppendixEofthisreport.
Asanalternativetousinganearthreturncircuit,two‐wiremonopolarHVDClines(usinganoverheadwireasthereturncircuit)alsoachieveacostsavingsrelativetoACintertiesalthoughthesavingswilltypicallybelessthanforanHVDCSWERtransmissionline.
BipolarHVDCintertiesrequiretheuseoftwoadditionalconvertersbutcantransfertwicetheenergyofacomparablemonopolarsystem.Intheeventofaconverterfailureorlossofaconductor,abipolarsystemcanbeconfiguredtooperateasamonopolarSWERormonopolartwo‐wiresystem.Thisofferssignificantreliabilityadvantages;however,italsoincursthecostoftheadditionalconvertersandsecondhigh‐voltageconductor.Theadvantagesoftheincreaseincapacityandreliabilityaretheprimaryreasonsforuseofbipolarsystems.
Page 33
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 19
3.5 SUBMARINECABLEINTERTIEALTERNATIVES
AnotheradvantageofHVDCtransmissionoverACisitsintrinsicabilitytocarryenergybyburiedorsubmarinecableoverlongdistanceswithoutthetechnicallimitationsandadditionalequipmentrequiredforsimilartransmissionbyAC.MonopolarHVDCusingasinglecablecanconnectvillagesseparatedbylakes,bays,fjords,orlandswhereoverheadtransmissionisnotpractical,cost‐effective,ordesirable.Forthisreason,low‐powerHVDCtechnologyhassignificantimplicationsforinterconnectingcommunitiesinAlaskaseparatedbywaterbodies,particularlyinthesoutheast.
CabletricitywasretainedbyPolarconsultasasubconsultanttoinvestigatesubmarinecablesoptimizedforusewiththisHVDCsystem.AppendixDincludestheCabletricityreportdetailingresultsoftheirinvestigations.
Thereportbeginswithadescriptionoftheelectricalsystemtowhichthecableswillbeconnected,andthenadvancestotheregionalenvironmenttheymustwithstandandontodescriptionsofsubmarinecablestandards,cabledesigns,typicalinstallationmethods,andcostestimatesforacasestudy.
Cabletricityevaluatedsubmarinecablessuitablefor1‐MWmonopolarHVDCintertiesat50kilovolts(kV),withpotentialupgradeoftheconverterstationsto5‐MWserviceinamonopolarcircuit.Cabletricityalsoevaluatedthefeasibilityandcostofintegratingopticalfibersintothepowertransmissionsystemtoservethecommunicationsneedsofruralcommunities.Tomakethissystempractical,simplicityandreliabilityarecriticaldesignconsiderations.
Cabletricity’sinvestigationsfocusedonsinglecoreinsulatedconductorsubmarinecableswithearthorseareturnthatwouldbegenerallysuitablefortheruggedanddeepinter‐islandandfjordcrossingstypicalofsoutheastAlaska.Theobjectiveistoidentifysuitableconventionalorinnovativesubmarinecabledesignstomeettheoverallprojectobjectiveswherewatercrossingsarerequired.
Page 34
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 20
4.0 HVDCCONVERTERSTATIONS
4.1 OVERVIEW
TheHVDCconverterstationswillincludethemajorcomponentslistedbelow:
● HVDCpowerconverterssuchasthosebeingdevelopedbyPPS;
● Converterenclosures,whichmayconsistofdedicatedenclosuresoruseofanexistingbuilding,suchasanexistingpowerplant;
● Protection,control,andswitchingequipmentontheACandHVDCsidesoftheconverters;
● ACtransformers,dependingontheACinterfacevoltageandwiring;and
● Groundingstations,includingthegroundconductorfromtheconverterstationtothegroundingstation.
4.2 CONVERTERDEVELOPMENTOVERVIEW
PolarconsultsubcontractedwithPPSforthedevelopmentoftheHVDCpowerconverters.PPSwastaskedwiththedevelopmentofonefull‐scaleandfull‐functionality1‐MWpowerconverter,consistingoftwo500‐kilowatt(kW)modules.Developmentworkincludedpreparationofspecifications,design,construction,andtestingoftheprototypeconverter.
TheHVDCconverterisa1‐MWpowerconvertercapableofbidirectionalpowerconversionbetweenthree‐phase480voltsalternatingcurrent(VAC)and50kVHVDC.TheconvertercapacityisappropriatetosupplytheelectricalneedsofmostAlaskavillageseconomically.Incontrast,existingHVDCpowerconvertersystemsareonlyavailableatmuchlargertransmissioncapacities,startingatapproximately50MWandextendingupto1,000sofMWsofcapacity.
Each500‐kWPPSconverterconsistsoftwomodules:anair‐cooledlow‐voltagecabinet(Figure4‐1),andanoilcooledhigh‐voltagetank(Figure4‐2).ACpowercablesconnecttothelow‐voltagecabinet,whichconditionsthepowerandtransformsittoaspecialhigh‐frequencyAC,whichistransmittedtothehigh‐voltagetankviapowercable.Thehigh‐voltagetanktransformsthehigh‐frequencyACto50kVDC.Thehigh‐voltagetankhastwobushingsthatoutputupto500kWat50kVDC.Eitherbushingcanbegroundedtoproduceapositive50‐kVHVDCoutputoranegative50‐kVHVDCoutput.
MultiplePPSHVDCconverterscanbe“paralleled”toachievehigherpowertransmissioncapacitieswhereneeded.BasedonPhaseIIdevelopmentwork,thepriceofacommerciallyproduced1‐MWHVDCpowerconverterisestimatedtobe$250,000.Atleasttwo1‐MWconvertersareneededforacomplete1‐MWHVDCtransmissionsystem.
PPShassuccessfullydemonstratedoperationandpowerflowatthefull50kVDCinbothinverter(HVDCtoAC)modeandrectifier(ACtoHVDC)modeinacontrolledtestfacilitysetting.Thesetestingeffortsvalidatethedesignandbasicfunctionalityoftheconverter.
Inthecourseoftesting,PPSidentifiedtwohardwareproblemsthatpreventedfull‐powertestingoftheprototypeconverters.PPShasinvestigatedtheseproblemsandidentifiedtheactionsnecessarytocorrectbothproblems.TheproblemsandsolutionsarediscussedinAppendixF.
Page 35
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 21
Thefollowingfiguresillustratetheconverterfeatures:
o Figures4‐1and4‐2showthetwobasicmodulesthatmakeupacomplete500‐kWconvertersystem.ThesearefurtherdiscussedinAppendixF.
o Figure4‐3showsthetestsetupfortestingofthecentralresonantlinkcircuitinthehigh‐voltageDCtransformer.
o Figure4‐4showsthein‐airhighpotential(hi‐pot)testsetupofthehigh‐voltageDCtransformerassembly.Thistestidentifiedsomeinsulationdefectsthatwerecorrected.ThetestdemonstratedthattheDCtransformerassemblywillwithstandthevoltagesexperiencedatfulloperatingvoltageof50kVDC.
o Figure4‐5showsthedrysystemtestsetupandschematic.BeforetheDCtransformerwasimmersedinoil,itwastestedatlowvoltageinairtovalidatefunctionandfacilitatetroubleshooting.Thiswasprimarilydoneforconvenience,toavoidthedelaysandmessassociatedwithrepeatedlyimmersingtheDCtransformerinoilandremovingit.
o Figure4‐6showsacomplete500‐kWconvertermodule,consistingoftheHVDCtankandthelow‐voltagealternatingcurrent(LVAC)cabinet.
o Figure4‐7showsfourhigh‐voltagemeasurementprobesusedtomonitorthevoltagesatdifferentpointsintheDCtransformer.ThetestshowedexcellentvoltagesharingbetweentheDCtransformerstages,indicatingthatthesystemisperforminginaccordancewithdesign.Uniformvoltagesharingisakeysuccess,asitmeansthepowerelectronicscomponentswillnotbesubjectedtounevenvoltagesstresses.Excessivevoltagestressescouldseverelyshortenthelifeofthecomponents,reducingthereliabilityoftheconverter.
Page 36
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 22
Figure 4-1 Low Voltage Alternating Current (LVAC) Enclosure: Mechanical Layout
Notes:Cabinetsize:66”Wx42”Dx66”H;Cabinetweight:Approximately2,200pounds.
Page 37
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 23
Figure 4-2 HVDC Transformer Tank: Mechanical Layout
Notes:Tanksize:88”Wx39”Dx59.25”H;Tankweightwithoil:4,200pounds.
Page 38
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 24
Page 39
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 25
Figure 4-3 Central Resonant Link Test Setup
Figure 4-4 Hi–Pot Test Setup for HVDC Transformer
Page 40
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 26
Figure 4-5 Dry System Inverter Mode Test Schematic and Setup
Page 41
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 27
Figure 4-6 System #1 HV Tank and LV Enclosure
Figure 4-7 System #1 Showing HV Measurement Probes
Page 42
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 28
4.3 ADDITIONALEQUIPMENT
4.3.1 ConverterEnclosure
WhiletheconverterspecificationspermittheconverterstobeinstalledoutdoorsinmostAlaskaenvironments,itisassumedthattheconverterswillbeinstalledinsideanenclosure.Thiswillprovideforacontrolledoperatingenvironmentandgreatersecurityfortheconverters,extendingtheirusefulservicelife.
Theconceptualdesignassumesthatamodular,prefabricatedenclosurewillbesenttothecommunitywiththetwo500‐kWpowerconverterunitsalreadyinstalled.Thisconvertermodulewillthenbesetinplaceonasuitablefoundation.
IncommunitiesthatwillbeprimarilyservedbyanHVDCintertie,itmaybeappropriatetolocatetheconvertersinsidetheexistingpowerhouseorothersuitableexistingstructure.Thiswouldhavethefollowingadvantages:
● Theexistingpowerhousemayalreadyhaveasuitablestep‐downtransformersizedforthefullcommunityload;
● Wasteheatfromtheconverterswouldprovideallorpartoftheheatforthepowerplantbuilding;and
● Achievesprojectcostreductionbyeliminatingtheneedforadedicatedconverterenclosureandpurchasingorleasinglandtositetheconverter.
4.3.2 ProtectionandSwitchyardEquipment
SwitchgearwillbeneededontheACsideoftheconverterstoisolateandprotecttheconverterfromtheACgridandtomonitorpowerflowbetweentheconverterandthegrid.
Similarisolation,protection,andmonitoringequipmentisneededontheHVDCsideoftheconverter.Ataminimum,manualdisconnectswitches(nonloadbreak),surgearrestors,andprotectivefusesareneededontheHVDCside.Moreautomatedcontrolapparatuscanalsobeused,butatincreasedcost.
4.3.3 ACTransformers
Thegridinterfaceonthepowerconvertersisthree‐phase480‐voltAC.Incommunitieswheretheconverterisconnecteddirectlytothe480‐voltpowerplantbus,notransformerisrequired.Incommunitieswheretheconverterconnectstothelocaldistributiongrid,astep‐uptransformerisrequired.Thetransformerwilltypicallybeathree‐phase480/12.47‐kVtransformer.
4.3.4 GroundingStations
AgroundingstationwillneedtobeprovidedateachHVDCconverterstation,regardlessoftheHVDCcircuitconfiguration.Theconceptualdesignofa1‐MW,50‐kVDCgroundingstationispresentedinAppendixE(FigureE‐1).
Page 43
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 29
5.0 DESIGNCONCEPTSFOROVERHEADINTERTIES
ThefollowingsummarizesdesigncriteriadevelopedfortheconceptualdesignoftheHVDCoverheadintertielines.DesigncriteriaandconceptualdesignsarepresentedindetailinAppendixC.
5.1 OVERHEADDESIGNAPPROACH
Theoverheadintertiedesignconceptspresentedrequiredconsiderationoftypicalsiteconditions,codes,utilityandlenderrequirements,constructionmethodologies,standarddesignpractices,andprojecteconomics.ThefollowingtwodesignapproachesforoverheadHVDCintertieshavebeenevaluated,eachwithacapacitytosupply1MWthroughamonopolar50‐kVDCsystem:
5.1.1 RUSDesignApproach,ModifiedforHVDCInterties
ThefirstconceptualdesignapproachisbasedontheuseofstructuresthatareconstructedinaccordancewithUSDARUS‐typeconstruction(RUSstandardpractice)forconventional12.4/24.9‐kVACdistributionlines.5TheseRUSstandardpracticesarecurrentlyusedtodevelopACintertiesthroughoutAlaskaandarewidelyacceptedbytheutilityindustry.HVDCtransmissionrequiresfewerconductorsthanAC,resultinginreducedloadsonthesupportingstructures.Asaresult,theconceptualdesignsdevelopedusingtheRUSapproachhavelongerrulingspansthantypicalAClines.ThisresultsinfewertransmissionstructuresfortheHVDCintertieandanassociatedcomparativereductioninconstructioncost.
5.1.2 Alaska‐SpecificDesignApproachforHVDCInterties
ThesecondconceptualdesignapproachtakesthelogisticandtechnicalchallengesofconstructioninruralAlaskaintoconsiderationandfocusesonmethodstoreduceconstructioncostswithoutcompromisingperformanceorlong‐termmaintainability.Thisdesignapproachincorporatescost‐savingfeaturesmadepossiblethroughHVDC‐specificdesignalternatives,materials,andconstructionmethods.DesignfeaturesofthisconceptincludetheuseofguyedcompositestructurestoallowsignificantlylongerrulingspansthanispossiblewithRUSstandardpractice.Thereducednumberofstructures,lesscostlyfoundations,andreducednumberofconductorsallresultinadditionalsavingscomparedwithintertiesbuiltinaccordancewithRUSstandardpractices.
ThefollowingthreeHVDCtransmissioncircuitconfigurationsareconsideredforeachoftheHVDCconceptualdesignapproaches:
● Monopolarsingle‐wiretransmissionwithearth‐returnpath(SWER);
● Monopolartwo‐wiretransmissionwithmetallicconductor‐returnpath(TWMR);
● Bipolartwo‐wiretransmission(2‐MWcapacity).
5 Inthisreport,theterm“RUSstandardpractice”referstooverheadintertielinedesignsbasedonthemethodsand
materialspresentedinRUSdesignmanualsfortransmissionanddistributionlineconstruction,includingbutnotlimitedto:REA,1982,RUS,1998,2002,2003a,2003b,2003c,and2009.
Page 44
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 30
SchematicfiguresareprovidedforeachoftheseconceptualdesignsinAppendixC.DetailedreportsthataddressvarioustechnicalaspectsoftheassumedconditionsandloadingsusedtodeveloptheseconceptualdesignsareprovidedasattachmentstoAppendixC.
5.2 GEOTECHNICALCONDITIONS
Basedontheanalysisdescribedbelow,conceptualfoundationdesignalternativesforaguyedpoleutilizethreethermoprobemicropilesforthepolebaseandhelicalanchorsfortheguys.TheoverheadsystemtestsiteinFairbanks,Alaska,featuresinstallationsofbothoftheseprototypefoundations.
5.3 ENVIRONMENTALLOADS
FivestandardNESCloadingcaseswereanalyzedforeachconceptualdesign.TheseloadcasesareconsideredsufficientformostruralAlaskaoverheadintertieapplications.Specificlocationsmaybesubjecttohigherand/orlowerwindand/oriceloadings.6Exceptwherespecificallystatedotherwise,eachoftheconceptualdesignspresentedinthissectioncomplywiththemoststringentoftheseloadconditions.
5.4 CONSTRUCTION,RUSSTANDARDPRACTICETheconceptualdesignsofoverheadintertielinespresentedinthissectionhavebeendevelopedtotakeadvantageofthefollowingfactors:
● Alaskacontractors,linecrews,andutilitylinepersonnelarefamiliarwithRUSstandardpracticematerials,designs,andconstructionpractices,thustheywillbemorefamiliarwiththetechniquesandproceduresforbuilding,maintaining,andrepairingtheselines.
● AlaskaalreadyhasmanymilesofRUSstandard‐practicedistributionandtransmissionlinesbuiltandinservicethroughoutthestate.Utilitiesunderstandtheperformancerecordandissueswiththistypeoflineconstruction.
● Utilitylenders,whichincludesRUS,understandandacceptRUSstandardconstructionpractice,whichcansimplifyobtainingfundsforconstructingnewinterties.
Totakeadvantageofthesefactors,conceptualdesignforHVDCpreservedRUSstandardpracticeconstructiontotheextentpossible,modifyingthepoletopassemblytoaccommodatetheconductor(s),insulator(s),andclearancesforHVDCoperation.TherulingspanisalsoincreasedtotakeadvantageofthefewerwiresandreducedstructureloadsassociatedwiththeHVDCcircuitconfigurations.
StructuralanalysisofconventionaloverheadHVDCtransmissionstructures(adaptedfromRUSstandardpractice)wasperformedbyPolarconsult.AconceptualdesignsummaryispresentedinAppendixCforeachofthelineconfigurationsproposed.
6 Section4.6ofthePhaseIFinalReportprovidesasummaryofenvironmentalloadingsaroundAlaska(Polarconsult,
2009)
Page 45
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 31
5.5 CONSTRUCTION,ALASKA‐SPECIFICCONCEPT
TheconceptualdesignsofoverheadintertielinespresentedinthissectionhavebeendevelopedtoreduceconstructioncostsonruralAlaskainterties.Costreductionisachievedthroughspecialattentiontothefactorslistedbelow.
● Minimizingtherelianceonheavyequipmentthatmustbemobilizedtoaconstructionsite.Iflighterequipmentorlocalequipmentcanbeusedforconstruction,mobilizationcostswillbeless,reducingprojectcosts.
● Maximizingtheflexibilityinconstructionmethodsandseasons.Bydesigningfortheuseofsmallerequipment,greateruseofhelicoptersforconstructionsupport,andsimilartechniques,all‐seasonconstructionbecomespossible,providingincreasedflexibilityforconstructiontechniquesandmethods.Thisincreasedflexibilitycreatesnewopportunitiestoincreaseutilizationofequipment,increasecompetitionforlineconstructionprojects,andreduceprojectcosts.
Thesefactorshavebeenincorporatedintotheconceptualdesignelementslistedbelow.
● Useoftallerstructuresandlongerspans.BecauseHVDCcircuitsrequireonlyoneortwowires,theycanutilizelongerspansthanacomparablethree‐orfour‐wireACcircuit.Increasingspansreducesthenumberofstructuresandfoundationsforagivenlengthofoverheadline,whichreducescosts.Withthisapproach,tallerstructuresareneededtomaintainrequiredclearancesbetweentheconductorandtheground.
● Useofglass‐fiber‐reinforcedpolymer(GFRP)polesinsteadofwoodorsteelpoles.GFRPpoleshavebeenusedforover50yearsinelectricutilityapplications7buthavelittletonohistoryinAlaska’selectricutilityindustry.GFRPpolesarelighterthanwoodorsteelpolessotheycanbetransportedbyasmallhelicoptersuchasaHughes500orBellUH‐1“Huey.”Theyarealsorot‐resistantanddonotleachtoxicpreservativesintothesoilsaroundthepole.ThePhaseIIprojectincludeddemonstrationofafield‐friendlyspliceforGFRPpoles,whichpermitstallpolestobeshippedinpartsandassembledinthefield.ThissplicecanalsobeusedforfieldrepairofdamagedGFRPpoles.
● Useofguyedstructuresinareaswheregeotechnicalconditionspreventcantileveredpolesfrombeingdirectlyburiedinthesoil.Acceptedpracticeforsuchconditionsistodriveasteelpileupto40feetdeepandthenfastenawoodpoletothesteelpile.Installingthesteelpilerequiresmobilizingacraneorotherheavyequipmenttotheprojectsite.Aguyedstructurecanbeinstalledinsuchconditionswithamuchsmallerbasefoundation,astheguyscarrymostofthemoment,andthestructurebasemostlycarriescompressiveloads.
7Ibrahim,2000.
Page 46
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 32
5.6 TESTINGOFOVERHEADDESIGNCONCEPTS
TheconceptualoverheaddesignsdescribedinAppendixCusecommerciallyavailableandacceptedmaterials,designs,andconstructionmethods.CertainaspectsoftheconceptualdesignspresentedrepresentinnovationsinoverheadlinedesignthatdonothaveaprovenrecordwithintheutilityindustryinAlaskaconditions.Inordertoevaluatetheperformanceofthesecomponents,theywereinstalledatatestsiteinFairbanks,Alaska.ThissectionsummarizestheobjectivesandinstallationoftheFairbanksTestSite.DetailsofthetestprogramarepresentedinAppendixC.
5.6.1 TestObjectives
TheprimarytestobjectivesoftheFairbanksTestSitearelistedbelow.
● Demonstrateperformanceandassemblytimeofaspliceforaconstant‐sectionGFRPutilitypole.
● Demonstrateinstallationandperformanceofmicro‐thermopilepolefoundations.
● Demonstrateinstallationandperformanceofmicro‐thermopileguyanchors.
● Demonstrateinstallationandperformanceofscrewguyanchors.
● DemonstratetheinstallationandperformanceoftheoverallguyedGFRPpolestructure.
● Demonstratemaintenanceandoperationalcharacteristics.
5.6.2 TestSite
ThetestsiteislocatedonprivatepropertysouthofFarmer’sLoopRoadandnorthofCreamers’FieldinFairbanks.Thesiteconsistsofwarmice‐richsiltypermafrostsoils.Thesitehasanorganiclayerconsistingofdeciduousshrubsandblackspruce.Peatwaspresentatdepthsof1to5feetbelowgroundsurface.TheactivelayerinSeptember2011extendedtoadepthof3feet,withstandingwaterencounteredwithinthevegetativematnearthesurface.Geotechnicalconditionsatthesitearecharacteristicofmarginalwarmpermafrostconditions,asfurtherdescribedinAppendixC.
Figures5‐1through5‐4showtheinstallationofinnovativematerialsandsystemsatthetestsiteinFairbanks.
Page 47
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 33
Figure 5-1 Installing Micro-Thermopile for Guy Anchor
ContractorGeoTekAlaska,Inc.drillingaholeforinstallationofamicro‐thermopileata45‐degreebatterangleusingaGeoProbe8040seriesdrillrig.Themicro‐thermopilewillserveasaguyanchorfortheprototypeguyed
GFRPpoleinstallationattheFairbanksTestSite.(Polarconsult,2011).
Page 48
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 34
Figure 5-2 Assembling the Prototype GFRP Pole Splice
ContractorCityElectric,Inc.installingthefieldsplicefortheprototypeGFRPpole.40‐footand20‐footGFRPpolesegmentsweresplicedtocreatethe60‐footpoleerectedatthesite.Thespliceslidesoverthepolesegmentsandcarriesmomentthroughcontactbetweenthepoleandsplicewalls.Verticalloadsarecarriedthroughthebuttendsofthepolesegments.Noglueoradhesiveisnecessaryforthesplicetodevelopthefullmechanicalstrengthofthepole.Thescrewsservetopreventdifferentialmovementbetweenthepoleandsplice.(Polarconsult,2011)
Page 49
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 35
Figure 5-3 Prototype GFRP Pole Foundation During Installation
DetailofprototypeGFRPpolebaseattheFairbanksTestSite.Theadapterplatewasadjustedduringinstallationsothehingeisorientedinlinewiththeguyanchorinthedistance(orangeflagging).Thiswillallowuseofthe
guyanchortolowerthepolewithawinchifneeded.(Polarconsult,2011)
Page 50
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 36
Figure 5-4 Prototype Pole at the Fairbanks Test Site
ViewoftheprototypeguyedGFRPpoleinstalledattheFairbanksTestSite.Thisphotographistakenatadistanceofapproximately25yardsfromthe60‐foot‐tallpole.Thefourguysandthepolesplicearevisibleinthis
photograph.(Polarconsult,2011)
Page 51
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 37
6.0 SYSTEMECONOMICS
TheextremevarietyofenvironmentalandtechnicalconditionsfoundacrossruralAlaskaresultsinasignificantvariationinintertiecosts.Thetypicalcostforconstructingaconventionaloverheaddistribution‐classACintertieinruralAlaskacanvaryfromaslittleas$100,000permiletoover$600,000permile8inpartsofthestatewithchallenginglogisticsandlittleornotransportation.Intertiecostvariationsalsoaffectsubmarinecables,undergroundcables,andotheroverheadintertieconfigurations.ThedetailsofsystemeconomicsarepresentedinAppendixB.
6.1 COSTCOMPARISONOFACANDHVDCOVERHEADINTERTIES
TwodistinctoverheadHVDCintertieconfigurationshavebeencomparedtoaconventionalACintertietoillustratearangeofHVDCintertieeconomicswithdifferentoverheaddesigns.ThetwoHVDCintertieconfigurationsare:
● Atwo‐wiremonopolarHVDCintertieusingRUSstandardpracticeconstructionmethods.ThisintertieconfigurationrepresentstheupperrangeofestimatedcostforanHVDCoverheadintertieinruralAlaskaapplications.
● AmonopolarSWERHVDCintertieusingAlaska‐specificconstructionmethods.ThisintertieconfigurationrepresentsthelowerrangeofestimatedcostforanHVDCoverheadintertieinruralAlaskaapplications.
TheestimatedcostforHVDCintertiesinmostruralAlaskaapplicationsisexpectedtofallbetweenthecostscitedforthesetwoconfigurations.
6.1.1 InstallationCostComparison
Figure6‐1presentstheestimatedinstalledcostrelativetotheintertielengthforthreedifferentkindsofintertiesbuiltinruralAlaskaconditions:
● AconventionalruralAlaskaintertie,
● Atwo‐wiremonopolarHVDCintertieusingRUS‐typeconstructionmethods,and
● AmonopolarSWERHVDCintertieusingAlaska‐specificconstructionmethods.
Additionally,Figure6‐1illustratestheeconomicbreak‐evenlengthandrelativeincreaseinsavingsforlongerHVDCinterties.ThepointsatwhichtheAC“costline”crosseseitheroftheHVDC“costlines”representstheeconomicbreak‐evenlength.TheestimatedHVDCcostsshowahypotheticalrangeofinstalledcostsanticipatedforlow‐power(under1MW)ruralAlaskaHVDCsystems.
8SeeSectionB.6.1inAppendixBforcostbasisinformation.
Page 52
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 38
Figure 6-1 Comparative Installed Cost: Overhead 1-MW HVDC and AC Interties
$0
$5,000,000
$10,000,000
$15,000,000
$20,000,000
$25,000,000
$30,000,000
$35,000,000
$40,000,000
$45,000,000
0 10 20 30 40 50 60 70 80 90 100
Intertie Length (miles)
Probab
le In
stalled Cost of Overhead HVDC vs. AC In
terties
AC Intertie (Standard RUS Construction)
HVDC Intertie (Monopolar, TWMR, Standard RUS Construction)
HVDC Intertie (Monopolar, SWER, Alaska‐Specific Construction)
BREAK‐EVEN COST FOR HVDC INTERTIES: 6 to 22 MILES
(INSTALLED‐COST BASIS)
Note: This chart is based on the assumptions and comparative system costs
presented in Appendix B. The break‐even point will vary for every intertie project.
COST SAVINGS
RANGE
AC
HVDC
HVDC
Page 53
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 39
6.1.2 Life‐CycleCostComparison
Operatingcosts,maintenancecosts,andelectricalefficiencyaffectthelong‐termeconomicvalueofanintertie.Table6‐1presentscomparativelife‐cyclecostsforhypothetical25‐mile‐longoverheadACandHVDCintertiesinruralAlaska.Alengthof25mileswasselectedasitconservativelyrepresentsthesavingsanticipatedforshortHVDCinterties.Theestimatedlife‐cyclecostfora25‐mile‐longHVDCintertierangesfrom79%to107%ofthelife‐cyclecostofanACintertie.
Table 6-1 Estimated Life-Cycle Costs for 25-mile Overhead AC and HVDC Interties
ParameterStandardRUSACIntertie
MonopolarTwo‐WireHVDCIntertie(RUSConstruction2)
MonopolarSWERHVDCIntertie
(Alaska‐SpecificDesign1)
CostofDiesel($/gallon[gal]) $7.00pergallon
GenerationEfficiency(kWh/gal) 13kWhpergallon
IntertieEfficiency4 97.7% 93.4% 94.5%
NetAnnualEnergyTransmission(kWh) 1,664,400
AnnualTransmissionLosses4(kWh) 38,300 133,000 114,000
AnnualizedValueofTransmissionLosses($) $21,000 $71,000 $61,000
IntertieDesignLife(years) 20years
IntertieAnnualOperationsandMaintenance(O&M)Costs
$40,000 $58,000 $54,000
EffectiveDiscountRate 3%
PresentWorthofTransmissionLosses $307,000 $1,063,000 $912,000
PresentWorthofO&MCosts $595,000 $867,000 $796,000
ConverterStationsInstalledCost $20,000 $2,080,000 $1,160,000
IntertieInstalledCost $9,480,000 $7,120,000 $5,340,000
EstimatedLife‐CycleCost $10,402,000 $11,130,000 $8,208,000
HVDCLife‐CycleCostasPercentofACLife‐CycleCost 107% 79%
PresentWorthSavings(Cost)ofHVDCvs.AC ($728,000) $2,194,000
Notes:1. “Alaska‐SpecificDesign”referstothedesignconceptspresentedinAppendixCofthisreport.2. “RUSConstruction”referstostandardRUSdesignandconstructionmethodsforACinterties,adaptedtoHVDC
applicationsasdescribedinAppendixCofthisreport.3. Allmonetaryvaluesarein2012dollars.4. Efficiencyandlossinformationincludesalltransmissionsystemcomponents.
Page 54
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 40
Figure6‐2illustratestheeconomicbreak‐evenlengthandrelativeincreaseinsavingsforlongerHVDCinterties.ThepointsatwhichtheAC“costline”crosseseitheroftheHVDC“costlines”representstheeconomicbreak‐evenlength.TheestimatedHVDCcostsrepresentahypotheticalrangeoflife‐cyclecostsanticipatedforlow‐power(under1MW)ruralAlaskaHVDCsystems.
Figure 6-2 Comparative Life-Cycle Cost: Overhead 1-MW HVDC and AC Interties
$0
$5,000,000
$10,000,000
$15,000,000
$20,000,000
$25,000,000
$30,000,000
$35,000,000
$40,000,000
$45,000,000
0 10 20 30 40 50 60 70 80 90 100
Intertie Length (miles)
Probab
le Life‐Cycle Cost of Overhead HVDC vs. AC In
terties
AC Intertie (Standard RUS Construction)
HVDC Intertie (Monopolar, TWMR, Standard RUS Construction)
HVDC Intertie (Monopolar, SWER, Alaska‐Specific Construction)
BREAK‐EVEN COST FOR HVDC INTERTIES: 12 to 31 MILES
(LIFE CYCLE COST BASIS)
Note: This chart is based on the assumptions and comparative system costs
presented in Appendix B. The break‐even point will vary for every intertie project.
AC
HVDC
HVDC
COST SAVINGS
RANGE
Page 55
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 41
6.2 CASESTUDIES
Thecasestudiesinthissectionprovideproject‐specificexamplesoftheexpectedcostsandresultingbenefitsofusingHVDCsystemstointerconnectcommunitiesandresources.Thesecasestudiesrelyonexistinginformationregardingtheproposedintertieroutes,loads,andrelatedprojectinformation.Figure6‐3presentsafewofthemanypotentiallow‐powerHVDCprojectsitesthroughoutAlaska.
Figure 6-3 Location Map for Potential HVDC Project Sites
Forthepurposesofthisreport,twospecificHVDCprojectsiteswereselectedforevaluation.The“GreensCreek–Hoonah”andthe“Nome–PilgrimHotSprings”intertieprojectsaretypicalofthedesignapproachandeconomicscommontootherHVDCAlaskaninterties.Table6‐2summarizesthecasestudiesconsideredinthissection.
Page 56
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 42
Table 6-2 Summary of Case Studies
HVDCIntertieCaseStudy
TransmissionCircuit
IntertieType
HVDCIntertieCost
Estimate1
ACIntertieCost
Estimate1
EstimatedHVDCSavings1
PercentCapitalCost
Savings
GreensCreek–Hoonah
5‐MWmonopolarHVDCcircuitwithseareturn2
SubmarineCable
$22.2million
$49million
$26.8million 55%
Nome–PilgrimHotSprings
5MWbipolarHVDCcircuit
OverheadLine
$25.7million
$36.3million
$10.6million 29%
Notes:
1. Allcostestimatesarepresentedin2012dollars.
2. Thecasestudyprovidesasubmarineandoverheadintertiecapacityof5MWandconverterstationcapacityof2MW.ThisprovidesanamplemarginforloadgrowthinHoonah.Theconverterstationcapacitycanbeupgradedasneededin500‐kWincrementsupto5MW.
6.2.1 Green’sCreek–HoonahCaseStudy
AnintertiebetweenGreensCreek,ontheAlaskaElectricLightandPowerCompany(AEL&P)gridthatservesJuneau,andthevillageofHoonah,anisolatedmicro‐gridoperatedbytheIPEC,hasbeenunderconsiderationforoveradecade.AEL&PandtheIPEChavecompletedextensivestudiesanddesignworkonthisintertie.Studiesidentifieda25‐mile‐longACsubmarinecableandapproximately4milesofoverheadlinenearHoonahasthemosteconomicalmeanstocompletethisinterconnection.9TheproposedintertierouteisshownonFigure6‐4.
Asthedevelopmentofthisprojectcontinued,thecostsoftheACsubmarinecablehaveescalated,untiltheprojectwasfinallyputonholdduetoitsexcessivecost.Hoonahiscurrentlyexploringlocalhydropowerresourcestoreduceitsenergycostsbutcontinuestoviewanintertieasthebestlong‐termsolutionforitsenergyneeds.
ThisHVDCsystemrepresentsatechnologicaladvancethatcanreducethecostoftheGreensCreek–HoonahintertieandincreaseitseconomicfeasibilityascomparedwithHoonah’sotherenergyoptions.Thefollowingsubsectionsofthiscasestudyprovideahigh‐levelanalysisofthemeritsofanHVDCintertieforHoonah.
Forthepurposesofthiscasestudy,a5‐MWmonopolarHVDCtransmissioncircuitwithseareturnwasselectedtoconnectHoonahwithGreen’sCreek.Thiscircuitconsistsof25milesofsubmarinecableand4milesofoverheadline.Amonopolarcircuitwasselectedbecauseitisexpectedtobetheleast‐costintertiesolutionbetweenHoonahandGreen’sCreek.Otherpotentialconfigurations,suchasabipolarHVDCcircuitutilizingtwosingle‐conductorcables,wouldbemoreexpensivethanthemonopolardesignselected.
9(PowerEngineers,2004)
Page 57
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 43
Theestimatedcapitalcostsincludea5‐MWtransmissioncircuit(submarinecableandoverheadline),and2‐MWconverterstationsatHoonahandGreen’sCreek.Theconverterstationscanbeupgradedto5MWbyadding500‐kWconvertermodulesasHoonah’sloadincreases.IfHoonah’sloadgrowsbeyond5MW,asecondsubmarinecablecanbeinstalledtoprovidea10‐MWbipolartransmissionsystem.
Figure 6-4 Greens Creek – Hoonah Intertie Route
6.2.1.1 EconomicAnalysis
Table6‐3presentstheeconomicanalysisfortheGreensCreek–Hoonahintertiealternatives.TheestimatedinstalledcostfortheHVDCintertieis$22.2million,ascomparedtothecostof$49millionforaconventionalACintertie.TheACintertiecostestimateisbasedonthe2009estimatedcostof$37.5million10adjustedto2012dollars.
10IPEC,2009.
Page 58
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 44
Table 6-3 Estimated Cost for a Greens Creek – Hoonah HVDC Intertie
CostItem EstimatedCost
PreconstructionRight‐of‐wayacquisition,engineering,survey,permitting $1,600,000
Administration/Management $900,000
HVDCConverterStations(powerconverters,seaelectrodes,enclosures,ACandDCsidestationequipment) $2,700,000
SubmarineCableSupplyandInstallation $12,400,000
OverheadHVDCLine:SpaaskiBaytoHoonah $900,000
Contingency(onentireproject,25%)1 $3,700,000
TotalEstimatedCost $22,200,000
Notes:1.Acontingencyof25%isappliedtothecostsdevelopedforthisprojectbasedontheuncertaintiesassociatedwiththeproject.Asignificantamountofworkhasalreadybeendonetocharacterizethebathymetryandseafloorconditionsalongtheproposedcableroute.
Page 59
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 45
Table6‐4presentsestimatedbenefit‐costratiosfortheGreensCreek–Hoonahintertieunderseveralloadgrowthscenarios.ThisanalysisindicatesacleareconomicadvantagetoanHVDCintertiebasedonreasonableloadgrowthforecastsforHoonah.
Table 6-4 Estimated Benefit-Cost Ratio of Greens Creek – Hoonah HVDC Intertie
ItemLoadGrowthScenario
ExistingLoad 165%Growth 200%Growth6
AnnualHoonahEnergyGeneration(kWh/yr)1 5,150,000 8,500,000 9,780,000
AEL&PAvoidedCostofEnergy(Juneau)2 $0.06perkWh
IPECAvoidedCostofEnergy(Hoonah)1 $0.20perkWh
IntertieOutageRate3 2%
AnnualHoonahSavings4 $707,000 $1,170,000 $1,340,000
IPECOperation,Maintenance,Repair,ReplacementandRehabilitation(OMR&R)AnnualCosts5 $90,000 $90,000 $100,000
NetAnnualSavings(Cost) $617,000 $1,150,000 $1,340,000
IntertieLifeandDiscountRate 30years,3%
PresentWorthofAnnualSavings(Costs) $12,070,000 $21,090,000 $24,500,000
EstimatedInstalledCost $22,200,000 $22,200,000 $22.200,000
EstimatedBenefit‐CostRatio 0.54 0.95 1.10
Notes:
1. BasedonPowerCostEqualization(PCE)reportsfor2007through2009(AEA,2010a).
2. ApproximateAEL&Penergycost.IPEChascapacity,sonodemandorcapacitychargesareincluded.
3. Assumedvalue.
4. AnnualsavingsarebasedonthedifferentialcostofenergyanddonotconsidereconomicbenefitsinHoonahfromlowercostenergy,oreffectstoAEL&Pofincreasedenergysales.
5. IPEC’sestimatedoperations,maintenance,repair,androutinereplacementcostsincludecostsfortheconverterstations,savingsfromdecreasedoperationandoverhaulofthedieselpowerplantinHoonah,andaone‐timecablerepaireventoverthe30‐yearanalysisperiod.
6. Hoonah’speakloadsundera200%loadgrowthscenariowouldexceedthe2‐MWcapacityoftheintertieconverterstations.Intertiethroughputisreducedby5%toreflectdieselgenerationinHoonah.
Page 60
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 46
6.2.2 PilgrimHotSprings–Nome
PilgrimHotSpringsisageothermalresourcelocatedapproximately60milesnorthofNome.IthasbeenproposedasapowersourcetoreduceNome’srelianceondieselfuelforelectricalgeneration.ACEPiscurrentlystudyingthePilgrimHotSpringsgeothermalresourcetobettercharacterizetheresource’spotentialforpowergenerationandotherapplications.ForpurposesofsizingthetransmissionlinefromPilgrimHotSprings,anelectricalgeneratingcapacityandtransmissioncapacityof5MWisassumed,basedonconversationswithACEP’smanagerforthePilgrimHotSpringsassessmentproject.11TheproposedtransmissionrouteisshownonFigure6‐5.
AbipolarHVDCcircuitusingoverheadlineswasselectedfortheHVDCintertie.Thebipolarconfigurationwasselectedbecauseitprovidesincreasedreliabilitycomparedtoamonopolarlineatareasonableadditionalcost.
ConceptualpowerlinecostsforoverheadACandHVDCintertieswereestimatedtoevaluatethebenefitsofconnectingPilgrimHotSpringstoNomeusinganHVDCintertie.ThecostestimatesindicatethatanHVDCtransmissionlinewouldcost29%lessthananACtransmissionline.
Aroutingstudywasnotperformedaspartofthiscasestudy.Powerlineswereroutedalongtheexistingroadcorridor.Thisisassumedtobetheleast‐costrouteforthepowerlines,astheroadcanbeusedtosupporttheconstructionandlong‐termmaintenanceoftheline.Aroutingstudymayidentifyotherroutesthataremorefavorableduetogeotechnical,landstatus,environmental,orotherfactors.
11PersonalcommunicationwithMarcusMager,2012.
Page 61
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 47
Figure 6-5 Prospective Transmission Route from Pilgrim Hot Springs to Nome
Page 62
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 48
6.2.2.1 EconomicAnalysis
Table6‐5presentstheeconomicanalysisforthePilgrimHotSprings–Nomeintertiealternatives.TheestimatedinstalledcostfortheHVDCintertiealternativeis$25.7million,ascomparedtothecostof$36.3millionforaconventionalACintertie.
NoinformationisavailablefortheinstalledcostofageothermalpowerplantatPilgrimHotSpringsorthecostoftheenergyitwouldgenerate,soabenefit‐costratiooftheintertiealternativeswasnotevaluated.
Table 6-5 Estimated Installed Cost for a 5-MW Pilgrim Hot Springs – Nome Intertie
CostItem
EstimatedInstalledCostforBipolarHVDC
Intertie
EstimatedInstalledCostforACIntertie
EstimatedHVDCSavings
PercentCostSavings
PreconstructionActivities(right‐of‐wayacquisition,design,survey,permitting)
$3,400,000 $3,400,000 ‐ ‐
Administration/Management $1,000,000 $1,300,000 ‐ ‐
ConverterStationConstruction $4,600,000 $3,000,000 ‐ ‐
OverheadIntertieConstruction $10,800,000 $20,200,000 ‐ ‐
Contingency(30%)1 $5,900,000 $8,400,000 ‐ ‐
TotalEstimatedCost $25,700,000 $36,300,000 $10,600,000 29%
Note:1. A30%contingencywasappliedtothecostsforthisprojectbecausenoinformationwasavailableforthe
transmissionroute.Thislackofdatacreatesrisksduetofactorssuchaslandavailability,geotechnicalconditions,structural(windandice)loadings,andenvironmental(bird,wildlife,andaesthetics)factors.Someoftheserisksaremitigatedbytheuseofcostdatafortherobustconceptualdesigns(i.e.,Alaska‐specificconstruction)usedfortheHVDCsystem.TheAlaska‐specificconceptualdesignisassumedtobeadequatefortheexpectedgeotechnicalandstructuralconditionsalongtheroute.Environmentalandlandavailabilityissues,whichcouldrequirealongerrouteordeparturefromtheroadcorridor,poserelativelygreaterrisksthanlinedesignconsiderations.Thenetresultofthesefactorsresultsinthe30%contingencyusedforthecasestudyeconomics.
Page 63
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 49
7.0 CONCLUSIONSANDRECOMMENDATIONS
7.1 CONCLUSIONS
PhaseIIhasdemonstratedthattheconvertertechnologyistechnicallyviableandthetransmissionsystemiseconomicallyfeasible.KeyPhaseIIfindingsare:
● Low‐powerHVDCconvertertechnologyisexpectedtobecommerciallyavailableat$250perkilowattperconverter.
● Estimatesofconstructioncostsforaconceptual25‐mileoverheadHVDCintertieindicatecapitalcostsavingsofapproximately30%comparedwithaconventionaloverheadACintertie.Estimatedlife‐cyclecostsrangefrom79%to107%ofthelife‐cyclecostofanACintertie.
● LongeroverheadHVDCintertiescanexpectcapitalcostsavingsofupto40%.
● SignificantsavingsarepossibleforsubmarinecableandundergroundcableapplicationsusingHVDCsystems.Estimatedcapitalcostsavingsona25‐milelow‐powerHVDCsubmarinecableintertieareover50%comparedtoACalternatives.
BasedonPhaseIIfindings,thebenefitsoflow‐powerHVDCsystemsforAlaskaaresubstantial,andcontinueddevelopmentofthissystemisrecommended.
7.2 OPPORTUNITIESANDBARRIERS
BasedonanalysisandstudyconductedduringthisPhaseIIproject,PolarconsulthasconcludedthatthisHVDCtechnologypresentsthefollowingopportunitiesforAlaska’sutilityindustryandruralcommunities:
● Lessexpensiveruralelectricinterties,leadingtolower‐costenergyandincreasedenergyindependenceforruralcommunities.
● Interconnectiontocurrentlystrandedenergyresources.
● Interconnectioncostsavingsbycombiningruralelectricandtelecommunicationsinterties.
Thesuccessfulcommercializationandadoptionoflow‐powerHVDCtechnologyinAlaskarequiresovercomingthefollowingbarriers:
● Completionofthecommercialdevelopmentanddemonstrationoftheconvertertechnology.Continueddevelopmentoftheprototypeconverters,culminatinginindependenttestingoftheconvertersanddeploymentonanAlaskautilitysystem,isneededtoprovethattheconvertersareacommerciallyviabletechnology.
● Acceptanceanduseoflow‐powerHVDCtechnologybyAlaska’sutilityindustry.Continuedinvolvementofin‐stateandinternationalstakeholderswiththeon‐goingdevelopmentofthistechnologyisconsiderednecessarytosurmountingthisbarrier.
● DevelopmentanddemonstrationofstandardsandcontrolprotocolsforMTDCtransmissionnetworks,whichareneededtobuildcost‐effectiveregionalHVDCpowernetworksinruralAlaska.
Page 64
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE 50
7.3 RECOMMENDATIONS
Basedontheconclusionsandfindingsofthisproject,thefollowingactionsarerecommended.
PhaseIIIprogramactivities:
● Continueddevelopmentofthepowerconvertertechnologytocommercializetheexistingprototypeconverterdesign.SolicitationofadditionalHVDCconvertermanufacturersiswarrantedtoencouragediversityofsuppliersandcompetition;
● Independenttestingoftheconverterstovalidateefficiencyandperformance,followedbydeploymentonanAlaskanutilitysystemtovalidatefunctionalityandreliabilityinacommercialsetting;
● FurtherdevelopmentofMTDCtransmissionsystemsinterconnectionandcontroltechnologies;and
● Continuedinvolvementofin‐statestakeholdersinthedevelopmentofthistechnology.
Stakeholderactions:
● Incorporatelow‐powerHVDCtechnologyintoAlaska’sregionalandstatewideenergyplansandpolicies;
● ContinuecoordinationwiththeStateofAlaskatoallowaproject‐specificwaiveroftheNESCtoallowtheuseofSWERcircuits;
● EncourageplannedruralpowerandtelecommunicationsintertiestoincorporateHVDCtechnologyintheireconomicandtechnicalanalysis,aswellastheirenvironmentalandpermittingreviewprocesses;
● Engagethetelecommunicationsindustrytoraiseawarenessofthesynergiespossiblebetweenlow‐powerHVDCtransmissionandfibernetworksinruralAlaska;and
● Collaboratewithinternationalstakeholderstoidentifysynergiesandlessonslearnedfromparalleltechnologydevelopmentefforts.Coordinateondevelopmentofapplicablepolicies/standardsandidentificationofmarketstohelpexpeditethecommercializationandreducethecostsoflow‐powerHVDCsystems.
Page 65
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE A-1
APPENDIXA
HVDCOVERVIEW
Page 66
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE A-2
Thispageintentionallyblank.
Page 67
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE A-3
TABLEOFCONTENTS
A.1 HIGH‐VOLTAGEDIRECTCURRENT(HVDC)TECHNOLOGY..................................................................5
A.2 SINGLE‐WIREEARTHRETURN(SWER)CIRCUITS...................................................................................7 A.2.1 WHYUSESWER?.............................................................................................................................................................7
A.3 SWERINALASKA.....................................................................................................................................................8 A.3.1 BETHEL–NAPAKIAKACSWERLINE..........................................................................................................................8 A.3.2 KOBUK–SHUNGNAKACSWERLINE..........................................................................................................................8 A.3.3 FUTUREOFSWERINALASKA........................................................................................................................................8
A.4 HVDCFORALASKA.................................................................................................................................................9
Page 68
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE A-4
Thispageintentionallyblank.
Page 69
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE A-5
A.1 HIGH‐VOLTAGEDIRECTCURRENT(HVDC)TECHNOLOGY
High‐voltagedirectcurrent(HVDC)convertertechnologyhasadvancedtousehigh‐efficiencysolid‐statehardware,andHVDClinksareutilizedforelectricaltransmissionthroughouttheworld.Whilethetechnologyhasadvancedconsiderablysincethe1950s,utilityapplicationofHVDCremainslimitedtotransmissionfunctions.Thesmallestutility‐gradeHVDCsystemsaredesignedtotransmitapproximately50megawatts(MW)12.SomenotableHVDCinstallationsinclude:
● SwedishMainlandtoGotlandIsland:20MW,100kilovolt(kV),monopolarsubmarinecablewithseareturn.Commissionedin1956,thiswasoneofthefirstHVDCintertiesinstalledintheworld.Thisoriginalsystemwasdecommissionedin198713.
● PacificIntertie–Celilo,Oregon,toSylmar,California:846‐mile,3,100MW,500kV,bipolaroverheadline.Commissionedin1970.
● BritishColumbiaMainlandtoVancouverIsland,Canada:45‐mile,682MW,260‐280kV,bipolarsubmarineandoverheadsystem.Thefirstpolewascommissionedin1968,andasecondpolewascommissionedin197714.
● NelsonRiverBipolarSystem,NelsonRiverHydroComplextoSouthernManitoba,Canada:TwobipolartransmissionsystemsoperatebetweenthehydropowerprojectsalongtheNelsonRiverinnorthernManitobaandWinnipeginthesouthernpartoftheprovince.Thefirstsystemisa540‐mile,1,620MW,450kVoverheadbipolarcircuitcommissionedin1977.Thesecondisa560‐mile,1,800MW,500kVoverheadbipolarcircuitcommissionedinstagesbetween1978and1985.Notably,bothsystemstraversepermafrostterrainsimilartothatfoundinAlaskaandcanoperateinSWERmode,moving1,000sofamperesofcurrentthroughearth‐return15.
● Cross‐SoundCable,NewHaven,Connecticut,toLongIsland,NewYork:24‐mile,330MW,150kVbipolarsubmarinecable.Commissionedin2002,thiscableusesABB'sHVDCLitetechnology.BothHVDCconductorsandafiber‐optictelecommunicationscablearebundledintoasinglecabletosimplifyinstallation16.
● England–FranceCrossChannelIntertie:38‐mile,160MW,100kVbipolarsubmarinecable.Theoriginalsystemwascommissionedin1961andreplacedin1986byalargersystemoperatingat270kVand2,000MW.Abipolarsystemwasoriginallyinstalledtoreducemagneticanomaliesthatcouldinterferewithshipping.
● Sardinia–Corsica–ItalianMainland,Italy:500MW,200kVbothearthandseareturns.Thefirst200MWpoleofthissystemwascommissionedin1965.Asecond300MWpolewasinstalledin1992.Thissystemisunusualbecauseitisamultipointsystem(servingthreeloadcenters),unlikemostHVDCinterties,whichtransmitpowerbetweenonlytwopoints.
12“HVDCLite,”distributedbyABB,isoneexampleofthesmallerutility‐gradeHVDCsystems.13 Theoriginalsystemusedon‐shoregroundinggridstocompletethetransmissioncircuitviaseaand/orseabedpathways.This
firstHVDClinkwasaugmentedbyasecond150MWmonopolarHVDClinktotheislandin1983,andathird150MWmonopolarlinkin1987.Today,thesetwonewercircuitsareoperatedtogetherasabipolartransmissionlink.
14 Thefirstmonopolarlineisratedfor312MWat260kV,andthesecondmonopolarlineisratedat370MWat280kV.15 http://www.hydro.mb.ca/corporate/facilities/ts_nelson.shtml16 CrossSoundCableConnectorProjectLiterature,www.abb.com
Page 70
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE A-6
● Fiveback‐to‐backHVDCconverterstations17interconnecttheTexasgridandU.S.electricgridinneighboringstates.Mostofthesestationswerecommissionedinthe1980s.Becauseofthesestations,TexashasanasynchronousgridconnectiontotheremainderoftheLower48.
● ThreeGorgesDamtoShanghai,China:530‐mile,3,000MW,500kV,bipolaroverheadline.FourHVDClinesareplannedbetweenThreeGorgesandChina'seasterncoastalregions.Thefirstbipolarcircuitwascommissionedin2003andthesecondin2006.
● VictoriatoTasmania,Australia:500MW,400kV,monopolarsubmarinecablewithseareturn.Commissionedin2005.
● SwedentoGermany,BalticCable:600MW,450kV,withearthreturnviadeepholeelectrodes.Commissionedin1993.
HVDClinkscanbesuperiortohigh‐voltagealternatingcurrent(AC)linksforseveralkeyreasons:
● HVDClinksarelesscostlyand/ormoreefficientthanAClinksundercertaincircumstances.
● Longintertiesutilizinginsulatedcables(asforsubmarineapplications)arepossiblewithHVDCelectricity,butprohibitivelydifficultwithACelectricityduetocablecapacitanceandreactivepowerlosses.
● HVDClinksprovideanasynchronousconnectionbetweenACelectricalgrids.Analogoustoaclutchonamechanicalsystem,anHVDCintertieallowseachACsystemtooperateatitsownphaseandfrequencyandstillallowpowertransferbetweenthesystems.ThiscanincreasethestabilityofbothACgrids.
● Foragivenpowertransferrequirement,HVDCintertiescanrequirelessright‐of‐waythancomparableACinterties.Theycanalsohaveavarietyofotherregulatory,permitting,orenvironmentaladvantagescomparedtoACinterties.
BecauseofthehighcostoftheconvertersystemsnecessarytoconvertHVDCtoamorereadilyusedACwaveform,HVDCisgenerallylimitedtotransmissionapplications.Accordingly,mostorallutilityHVDCsystemsinusetodayarepoint‐to‐pointtransmissionlines,withnointermediatetake‐offpointsorsubstationsforcommunitiesenroute.
Forthesmall‐scaleruralAlaskaHVDCapplicationsconsideredinthisstudy,thereisstillaneconomicbarrierduetothecostoftheHVDCconverters(estimatedat$250,000perMWin2012dollars).Forexample,aremotelodgeorfishcamplikelycannotjustifythecosttotaptheHVDCline,butmostvillagescan.
AsHVDCintertiesareconsideredforruralAlaskaapplications,utilitiesmaydesiretoextendACdistributionasanunderbuildoroverbuildonanoverheadHVDCline.Similarly,otherutilitiesmaydesiretoutilizetheoverheadstructurestoco‐locatetheircables.Thispracticeispossiblesolongasapplicablecoderequirementsandsafetyprovisionsarefollowed.Itmaybedesirabletouseconventionalconstructionintheimmediatevicinityofvillagestofacilitatecolocationofmultipleutilitycables,transitioningtoadifferent,optimizedoverheadstructureforHVDConceawayfromthevillage.
17 ThefiveHVDCsystemsarethe220‐MWback‐to‐backNorthDCTie,600‐MWback‐to‐backEastDCTie,36MVAback‐to‐back
EGPSDCTie,150MVAback‐to‐backRAILDCTie,and80MVALaredovariablefrequencytransformer(VFT)Tie.(www.ercot.com).
Page 71
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE A-7
A.2 SINGLE‐WIREEARTHRETURN(SWER)CIRCUITS
Initssimplestform,anelectricalcircuitrequirestwocurrentpathways,typicallywires.Onewiregoesfromthepowersupplytotheload,andasecondwiregoesfromtheloadbacktothepowersupply.Bothsingle‐phaseACandDCcircuitsrelyonthisbasicconfiguration.Thewirefromthepowersupplytotheloadisusuallyatanincreasedvoltagerelativetoground,andsoitisinsulatedforsafetyandtopreventshortcircuits.Thewirefromtheloadbacktothepowersupplyisusuallyatamuchlowervoltagerelativetogroundandthusisusuallybutnotalwaysinsulated.
Insingle‐wireearthreturn(SWER)circuits,thewirethatservesasthesecondcurrentpathwayfromtheloadbacktothepowersupplyisreplacedwithasuitable,convenient,andsafecurrentpathway.Inthemostgeneralcase,this“non‐wire”pathwaycanbeacarortruckchassis,themetalhandleofaflashlight,theearth,naturalwaterbodies,orotherobjectsthatcansafelycompletetheelectricalcircuit.
Seareturncircuitsaresimilartoearthreturncircuits.Theonlydifferenceisthatthesea,oranywaterbody,isusedasthepredominantreturncircuitpathway.Parallelpathways,suchastheseabed,arealsoavailableforcurrentflow.
A.2.1 WhyUseSWER?
TheprimaryadvantagesofferedbySWERcircuitsinclude:
● Lowercosts(eliminatethesecondconductor).
● Higherefficiency(lowerelectricallosses).
TheprimaryconcernsassociatedwithSWERcircuitsinclude:
● AvoidingcorrosionofburiedorsubmarinemetallicobjectsinthevicinityoftheSWERcircuit.
● Aswithallelectricalsystems,safety.
SWERcircuitsarewidelyusedforutilitytransmissionanddistributionofelectricityallovertheworld.NumerousHVDCintertiesareSWERcircuits,consistingofasinglehigh‐voltagecableandanearthorseareturntocompletethetransmissioncircuit.ManyoftheseareinstalledinclimatesandconditionssimilartoAlaska,notablyinScandinavia.Inmanynations,single‐phaseACSWERcircuitsareacceptedpracticeandareindustrystandardforservingruralareas.
NationsandjurisdictionsthatuseSWERACcircuitstoservetheirruralareaseconomicallyincludethefollowing18,19.
● Australia(over100,000milesinservice)
● Cambodia(Electricite’duCambodge)
● NewZealand
● Vietnam
● Laos(Electricite’duLaos)
● SouthAfrica(EskonDistribution)
18 “SingleWireEarthReturnforRemoteRuralDistribution,ReducingCostandImprovingReliability.”ConradW.Holland.
MaunsellLtd.,AnAECOMCompany.19 “SingleWirePowerinAlaska.”StateofAlaska,DivisionofEnergyandPowerDevelopment.R.W.RutherfordAssociates.1982.
Page 72
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE A-8
● Saskatchewan
● India
● Brazil
A.3 SWERINALASKA
Atleasttwosingle‐phaseACSWERcircuitshavebeensuccessfullybuiltandoperatedinAlaska.TheseACSWERcircuitsdemonstratethatSWERisaproven,beneficial,andappropriatetechnologyforruralAlaskatransmissionapplications.
A.3.1 Bethel–NapakiakACSWERLine
In1981,a10.5‐mile14.4kVsingle‐phaseACSWERlinewasconstructedtoconnectthesmallvillageofNapakiaktotheCityofBethel.Thislineusedbipodstructurestosuspenda7#8Alumoweldconductor.
Thislinewasconstructedatacostof$23,000permile(1980$)andoperatedsuccessfullyformanyyears.Arguably,thelinehadtwoshortcomings,neitherrelatedtoitsSWERoperation:(1)thestructuraldesignofthelinereliedupontheconductortoprovidelongitudinalsupporttothebipodpolesbetweendeadends,andonatleastoneoccasionaconductorbreakcausedaseriesofstructurestofalldown;and(2)overtime,theloadinNapakiakexceededtheline'scapacity.However,thelinewasanunqualifiedsuccessatdemonstratingthatSWERcanreducethecostsofpowertransmissioninruralAlaska.
Commonmisperceptionsaboutthislinehavegivenitanegativereputation,whichisoftenincorrectlyattributedtoits“innovative”SWERdesign.Thelinedidsufferhighlosses,butthesecanbeattributedtounmeteredloadsinNapakiakandthepoorconditionofthedistributionsysteminNapakiak.
TheAlaskaEnergyAuthorityreplacedtheBethel‐Napakiaklinewithaconventionalthree‐phaselinein2010.Theinstalledcostofthisreplacementwasapproximately$344,000permilein2012dollars,approximatelythreetimesgreaterthantheinflation‐adjustedcostoftheoriginalline20.
A.3.2 Kobuk–ShungnakACSWERLine
A10‐milesingle‐phaseACSWERlinewasconstructedtoconnectthevillageofShungnaktoKobukinnorthwesternAlaska.ThelineandtheSWERsystemworkedsuccessfully;however,thesupportstructureswereconstructedoflocalsprucetrees,andeventuallythebasesrotted.LiketheBethel–NapakiakSWERline,thislinealsosuccessfullydemonstratedSWERviabilityinpermafrostregions.In1991,this10‐milelinewasreplacedwithaconventionalthree‐phase7.2/12.4kVAClinewithpolesattachedtodrivensteelH‐pilesatacostof$1.1million,orabout$110,000permilein1991dollars21.
A.3.3 FutureofSWERinAlaska
ThetransitionofmostAlaskavillagestothree‐phasedistributionsystemshasdiminishedthevalueofsingle‐phaseACSWERinterties.ACphaseconverterswouldbenecessarytointerfacetheintertiewithoneorbothvillagegrids.Inaddition,thenationalelectricalcodesadoptedbytheStateofAlaskadonotallowtheuseofSWERcircuitsforroutinepowertransmissionordistribution.Perhapsbecauseofthesefactors,thereiscurrentlyagenerallackofinterestinSWERtechnologyinAlaska.
20 (AEA,2007);(DC,2010).21 Petrie,Brent.AlaskaVillageElectricCooperative,Inc.PersonalCommunication.February2008.
Page 73
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE A-9
Despitesuchfactors,SWERcircuitsremainaprovenandcost‐effectiveoptionforruralAlaskaapplications,andtheywarrantseriousconsideration.CoupledwithHVDC,SWERofferscostandtechnicaladvantagesthathavethepotentialtorevolutionizeruralpowertransmissioninAlaska.
AffordableenergyisavitalunderpinningofcreatingasustainableeconomicbaseforAlaska'sruralareas.Affordabletransmissioniskeytoachievingaffordableenergy,andthecouplingofSWERandHVDCpresentsthebrightestopportunityforachievingaffordabletransmissioninAlaska.Accordingly,thefutureofSWERinAlaskaisverypromising.
A.4 HVDCFORALASKA
ThelistofexistingHVDCprojectsinSectionA.2illustratesthefactthattoday'scommercialHVDCtechnologyremainslimitedtolarge‐scaletransferofelectricity,normallymeasuredinthe100sor1,000sofmegawatts.SuchtechnologyhasverylimitedapplicationinAlaska,asourlargestutilitygrid,alongtherailbelt,hasapeakloadofwellunder1,000MW.Mostruralloadsaremeasuredinthe100sofkW.
ThelackofcommercialHVDCtechnologyinthekilowattclassnecessaryforruralAlaskaapplicationsmeansthatthenumerousbenefitsofferedbyHVDCtransmissionarenotpresentlyavailabletoAlaska'sruralcommunities.ThekeyobjectiveandimpetusforthisprojectistolowerthecostofruralAlaskaintertiesbyextendingthereachofcommerciallyavailableHVDCtechnologydowntothekilowattclassneededtoserveAlaska'sruralenergytransmissionneeds.
TheapplicationsforthistechnologyinAlaskaarenumerousandinclude:
● ConnectingBethelandnearbyvillageswithawindfarmalongtheBeringSeacoast.
● ConnectingvillagesalongtheYukonRiversuchasKoyukuk,Nulato,Ruby,andKaltagwiththeproposedToshibanuclearbatteryinGalena.
● Connecting25southwesterncommunitiestoaproposed25‐MWgeothermalplantnearKingSalmon.
● ConnectingNorthSlopecommunitiessuchasAtqusukwithBarrowtoshareinthelow‐costelectricityderivedfromBarrow’sgasfields.
● DevelopingthegeothermalresourceatPilgrimHotSpringsandtransmitthepowertoNomeviaHVDCintertie.
● CompletingconnectionsintheSoutheastIntertieviaanaffordableHVDCsubmarinecable.
A.3.9 DesignConsiderationsforSmallAlaskaHVDCInterties
ManyofthetechnicalaspectsofdesigningandbuildingsmallHVDCintertiesinAlaskaaremuchthesameasforbuildingintertiesanywhere.ThesingledominatingfactorthatsetsconstructioninruralAlaskaapartislogistics.Mostprojectshavelittleornosupportinfrastructure,rangingfromthebasicssuchasmodernlodgingforworkerstoavailabilityoftransportationinfrastructure,heavyequipment,skilledlabor,andsoon.
ManymajorconstructionprojectsaddressthelogisticalchallengesofruralAlaskabyimportingeverythingnecessarytogetthejobdonebyconventionalmeans.Thisworks,butisverycostly.
Adifferentsolutiontothelogisticschallengeistotailorthedesigntouseavailablelocalresourcestotheextentpossible.Thisisaverychallengingproposition,buttherewards–lowerconstructioncosts–aresubstantial.Ingeneralterms,designingforAlaskalogisticsmeans:
Page 74
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE A-10
● Usematerialsandequipmentthatarereadilyshippedbycommontransportationmethods,suchassmallcargoaircraft22.Usematerialsandconstructionmethodsthatcanutilizesmall,lowgroundpressureequipmenttoenableconstructionduringsummerorautumnthawedconditions.
● Usematerialsandconstructionmethodsthatemploylocallyavailableequipmentfortransportandconstructionasmuchaspossible.
● Reducetheamountofconstructionandfabricationrequiredinthefieldandontheline.Pre‐manufactureandpreassemblebeforeshippingtothevillagesorinthevillagesbeforeshippingtothefieldtoreducecostsandincreasequality.
● Optimizetheconstructionandassemblymethodstoemploylocallyavailablelabor.
22 ThelargestcargoaircraftsuitableforAlaskalogisticplanningisaHerculesC‐130,butmanyvillageairstripscannot
accommodateaHercules.AmoreuniversalcargoaircraftforremoteAlaskaprojectsisaSherpaSD‐330orsimilarsmallcargoaircraft.
Page 75
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-1
APPENDIXB
ECONOMICANALYSIS
Page 76
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-2
Thispageintentionallyblank.
Page 77
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-3
TABLEOFCONTENTS
B.1 INTRODUCTION........................................................................................................................................................7
B.2 ECONOMICANALYSIS............................................................................................................................................8 B.2.1 COMPARATIVECOST:ACVERSUSHVDCOVERHEADINTERTIES.............................................................................8 B.2.2 INSTALLATIONCOSTCOMPARISON................................................................................................................................8 B.2.3 LIFE‐CYCLECOSTCOMPARISON...................................................................................................................................10
B.3 COSTANALYSISBASIS.........................................................................................................................................12 B.3.1 GENERATIONANDLOADASSUMPTIONS......................................................................................................................12 B.3.2 SYSTEMEFFICIENCYASSUMPTIONS.............................................................................................................................12 B.3.3 OPERATION,MAINTENANCE,ANDREPAIRASSUMPTIONS.......................................................................................12 B.3.4 ECONOMICASSUMPTIONS..............................................................................................................................................13 B.3.5 INSTALLEDCOSTASSUMPTIONS...................................................................................................................................13
B.4 CASESTUDIES.........................................................................................................................................................14 B.4.1 GREEN’SCREEK–HOONAHCASESTUDY....................................................................................................................14 B.4.2 PILGRIMHOTSPRINGS–NOME....................................................................................................................................19
B.5 DETAILEDHVDCINTERTIECOSTINFORMATION..................................................................................23 B.5.1 OVERHEADINTERTIECOSTDETAIL.............................................................................................................................23 B.5.2 SUBMARINECABLEINTERTIECOSTDETAIL...............................................................................................................25 B.5.3 UNDERGROUNDCABLEINTERTIECOSTDETAIL........................................................................................................25 B.5.4 CONVERTERSTATIONCOSTDETAIL............................................................................................................................26
B.6 DETAILEDACINTERTIECOSTINFORMATION........................................................................................30 B.6.1 COSTBASELINESFOROVERHEADACINTERTIES......................................................................................................31 B.6.2 COSTBASELINEFORSUBMARINECABLEACINTERTIES..........................................................................................33
Page 78
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-4
Thispageintentionallyblank.
Page 79
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-5
LISTOFTABLES
TableB‐1 EstimatedLife‐CycleCostsfor25‐mileOverheadACandHVDCInterties.......................10
TableB‐2 SummaryofCaseStudies......................................................................................................................14
TableB‐3 EstimatedCostforanGreensCreek–HoonahHVDCIntertie...............................................17
TableB‐4 EstimatedBenefit‐CostRatioofGreensCreek–HoonahHVDCIntertie..........................18
TableB‐5 EstimatedInstalledCostfora5‐MWPilgrimHotSprings–NomeIntertie.....................22
TableB‐6 EstimatedCostfora25‐mileOverheadHVDCIntertie............................................................24
TableB‐7 EstimatedCostsfora25‐mileUndergroundHVDCIntertie..................................................26
TableB‐8 1‐MWHVDCConverterStationCostEstimate.............................................................................27
TableB‐9 HVDCConverterEnclosureCostDetail...........................................................................................27
TableB‐10 SwitchgearandSwitchyardCostDetail..........................................................................................28
TableB‐11 HVDCGroundingStationCostDetail................................................................................................29
TableB‐12 CostBaselinesforRemoteAlaskaACIntertieConstruction..................................................30
TableB‐13 EstimatedCostsforOverheadACInterties...................................................................................31
TableB‐14 InstalledCostsofRecentRemoteAlaskaOverheadACInterties.........................................32
TableB‐15 InstalledCostsofRecentRemoteAlaskaSubmarineCableInterties.................................33
Page 80
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-6
LISTOFFIGURES
FigureB‐1 ComparativeInstalledCost:Overhead1‐MWHVDCandACInterties.................................9
FigureB‐2 ComparativeLife‐CycleCost:Overhead1‐MWHVDCandACInterties............................11
FigureB‐3 GreensCreek–HoonahIntertieRoute............................................................................................15
FigureB‐4 ProspectiveTransmissionRoutefromPilgrimHotSpringstoNome................................20
Page 81
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-7
B.1 INTRODUCTION
TheextremevarietyofenvironmentalandtechnicalconditionsfoundacrossruralAlaskaresultsinasignificantvariationinintertiecosts.Thetypicalcostforconstructingaconventionaloverheaddistribution‐classalternatingcurrent(AC)intertieinruralAlaskacanvaryfromaslittleas$100,000permileinareaswithgoodlogisticsupportgeotechnicalconditionsandtransportationinfrastructure(roadsystem,southeast)toover$600,000permile23inpartsofthestatewithchallenginglogisticsandlittleornotransportationinfrastructure(remoteinterior,northwest,orYukon‐Kuskokwimdeltaregions).
Intertiecostvariationsalsoaffectsubmarinecables,undergroundcables,andotheroverheadintertieconfigurations.
Thisappendixprovidesthefollowingeconomicanalyses:
● ComparativepresentworthanalysisofconceptualACandhigh‐voltagedirectcurrent(HVDC)interties;
● CasestudiesofAlaskaHVDCinterties;
● EstimatedcostsforconceptualHVDCinterties;and
● BaselinecostsforruralAlaskaACinterties.
23SeeSectionB.6.1forinformationonthecostbasisofruralAlaskaACinterties.
Page 82
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-8
B.2 ECONOMICANALYSIS
ThissectionevaluatescomparativecostsforconceptualACandHVDCinterties.BecauseHVDCintertiesincurtheaddedexpenseofconverterstations,shortHVDCinterties(underapproximately6to31miles)willgenerallynotbecost‐effectivecomparedwithACinterties,dependingonproject‐specificconditions.
Astheintertielengthincreases,thelowerper‐milecostofthetransmissionlineoffsetstheadditionalcostofthepowerconverters.HVDCintertiesshorterthanacertaineconomic“break‐even”lengthwillbemorecostlythanacomparableACintertie.TherelativesavingspossiblewithanHVDCtransmissionsystemincreasesforintertielengthsabovethisbreak‐evenlength.
Basedonspecificprojectconditions,andontheassumptionsandanalysisdescribedherein,theconceptualbreak‐evenlengthforoverheadintertiesisapproximately6to22milesonaninstalled‐costbasis,and12to31milesonalife‐cyclecostbasis.Theconditionsandassumptionsusedtodeveloptheseeconomicbreak‐evenlengthestimatesareprovidedinthisappendix.
B.2.1 ComparativeCost:ACversusHVDCOverheadInterties
TwodistinctHVDCintertieconfigurationshavebeencomparedtoaconventionalACintertietoillustratethedifferenceinprojecteconomics.ThetwoHVDCintertieconfigurationsare:
● Atwo‐wiremonopolarHVDCintertieusingU.S.DepartmentofAgriculture(USDA)RuralUtilitiesService(RUS)‐typeconstructionmethods.ThisintertieconfigurationrepresentstheupperrangeofestimatedcostforanHVDCoverheadintertieinruralAlaskaapplications.
● Amonopolarsingle‐wireearthreturn(SWER)HVDCintertieusingAlaska‐specificconstructionmethods.ThisintertieconfigurationrepresentsthelowerrangeofestimatedcostforanHVDCoverheadintertieinruralAlaskaapplications.
ThecostforHVDCintertiesinmostruralAlaskaapplicationsareexpectedtofallbetweenthecostestimatescitedforthesetwoconfigurations.
B.2.2 InstallationCostComparison
FigureB‐1presentstheestimatedinstalledcostrelativetotheintertielengthforthreedifferentkindsofoverheadintertiesbuiltinruralAlaskaconditions:
● AconventionalruralAlaskaintertie,
● Atwo‐wiremonopolarHVDCintertieusingRUS‐typeconstructionmethods,and
● AmonopolarSWERHVDCintertieusingAlaska‐specificconstructionmethods.
Page 83
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-9
Inaddition,FigureB‐1illustratestheeconomicbreak‐evenlength,andrelativeincreaseinsavingsforlongerHVDCinterties.ThepointsatwhichtheAC“costline”crosseseitheroftheHVDC“costlines”representstheeconomicbreak‐evenlength.TheestimatedHVDCcostsrepresentahypotheticalrangeofinstalledcostsanticipatedforlow‐power(under1megawatt[MW])ruralAlaskaHVDCsystems.
Figure B-1 Comparative Installed Cost: Overhead 1-MW HVDC and AC Interties
$0
$5,000,000
$10,000,000
$15,000,000
$20,000,000
$25,000,000
$30,000,000
$35,000,000
$40,000,000
$45,000,000
0 10 20 30 40 50 60 70 80 90 100
Intertie Length (miles)
Probab
le In
stalled Cost of Overhead HVDC vs. AC In
terties
AC Intertie (Standard RUS Construction)
HVDC Intertie (Monopolar, TWMR, Standard RUS Construction)
HVDC Intertie (Monopolar, SWER, Alaska‐Specific Construction)
BREAK‐EVEN COST FOR HVDC INTERTIES: 6 to 22 MILES
(INSTALLED‐COST BASIS)
Note: This chart is based on the assumptions and comparative system costs
presented in Appendix B. The break‐even point will vary for every intertie project.
COST SAVINGS
RANGE
AC
HVDC
HVDC
Page 84
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-10
B.2.3 Life‐CycleCostComparison
Operatingcosts,maintenancecosts,andefficiencyaffectthelong‐termeconomicvalueofanintertie.TableB‐1presentscomparativelife‐cyclecostsforhypothetical25‐mile‐longoverheadACandHVDCintertiesinruralAlaska.Alengthof25mileswasselectedasitrepresentsthesavingspossibleusingarelativelyshortHVDCintertie.Theestimatedlife‐cyclecostfora25‐mile‐longHVDCintertierangesfrom79%to107%ofthelife‐cyclecostofanACintertie.
Table B-1 Estimated Life-Cycle Costs for 25-mile Overhead AC and HVDC Interties
ParameterStandardRUSAC
Intertie
MonopolarTwo‐WireHVDCIntertie(RUSConstruction2)
MonopolarSWERHVDCIntertie
(AlaskaSpecificDesign1)
CostofDiesel($/gal) $7.00pergallon
GenerationEfficiency(kWh/gal) 13kWhpergallon
IntertieEfficiency4 97.7% 93.4% 94.5%
NetAnnualEnergyTransmission(kWh) 1,664,400
AnnualTransmissionLosses4(kWh) 38,300 133,000 114,000
AnnualizedValueofTransmissionLosses($) $21,000 $71,000 $61,000
IntertieDesignLife(years) 20years
IntertieAnnualO&MCosts $40,000 $58,000 $54,000
EffectiveDiscountRate 3%
PresentWorthofTransmissionLosses $307,000 $1,063,000 $912,000
PresentWorthofO&MCosts $595,000 $867,000 $796,000
ConverterStationsInstalledCost $20,000 $2,080,000 $1,160,000
IntertieInstalledCost $9,480,000 $7,120,000 $5,340,000
ESTIMATEDLIFE‐CYCLECOST $10,402,000 $11,130,000 $8,208,000
HVDCLIFE‐CYCLECOSTASPERCENTOFACLIFE‐CYCLECOST 107% 79%
PRESENTWORTHSAVINGS(COST)OFHVDCVS.AC ($728,000) $2,194,000
Notes:1. “Alaska‐SpecificDesign”referstothedesignconceptspresentedinAppendixCofthisreport.2. “RUSConstruction”referstostandardRUSdesignandconstructionmethodsforACinterties,adaptedtoHVDCapplications
asdescribedinAppendixCofthisreport.3. Allmonetaryvaluesarein2012dollars.4. Efficiencyandlossinformationincludesalltransmissionsystemcomponents.
Page 85
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-11
FigureB‐2illustratestheeconomicbreak‐evenlength,andrelativeincreaseinsavingsforlongerHVDCinterties.ThepointsatwhichtheAC“costline”crosseseitheroftheHVDC“costlines”representstheeconomicbreak‐evenlength.TheestimatedHVDCcostsrepresentahypotheticalrangeoflife‐cyclecostsanticipatedforlow‐power(under1MW)ruralAlaskaHVDCsystems.
Figure B-2 Comparative Life-Cycle Cost: Overhead 1-MW HVDC and AC Interties
$0
$5,000,000
$10,000,000
$15,000,000
$20,000,000
$25,000,000
$30,000,000
$35,000,000
$40,000,000
$45,000,000
0 10 20 30 40 50 60 70 80 90 100
Intertie Length (miles)
Probab
le Life‐Cycle Cost of Overhead HVDC vs. AC In
terties
AC Intertie (Standard RUS Construction)
HVDC Intertie (Monopolar, TWMR, Standard RUS Construction)
HVDC Intertie (Monopolar, SWER, Alaska‐Specific Construction)
BREAK‐EVEN COST FOR HVDC INTERTIES: 12 to 31 MILES
(LIFE CYCLE COST BASIS)
Note: This chart is based on the assumptions and comparative system costs
presented in Appendix B. The break‐even point will vary for every intertie project.
AC
HVDC
HVDC
COST SAVINGS
RANGE
Page 86
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-12
B.3 COSTANALYSISBASIS
B.3.1 GenerationandLoadAssumptions
Thefollowinggenerationandloadassumptionsareusedasthebasisofthecostanalysis:
● Energytransmittedoverallintertieconfigurationsisassumedtobegeneratedbyadiesel‐electricplantoperatingataconstantefficiencyof13kilowatt‐hours(kWh)pergallon;
● Thepriceofdieselisassumedtobe$7.00pergallon;and
● Noescalatorisappliedtothepriceoffuelovertime.
B.3.2 SystemEfficiencyAssumptions
ThefollowingcircuitpathisassumedfortheACintertiecase:
● Generationat480voltsalternatingcurrent(VAC)incommunity“A”;
● Stepupto7.2/12.47kilovolts(kV)ACatthepowerplantincommunity“A”;and
● Transmissionat7.2/12.47kVACtothereceivingcommunity“B.”
ThefollowingcircuitpathisassumedfortheHVDCintertiecases:
● Generationat480VACincommunity“A,”
● Conversionfrom480VACto50kVdirectcurrent(DC)atthecommunity“A”powerplant,
● Transmissionat50kVDCtothereceivingcommunity“B,”
● Conversionfrom50kVDCto480VACatthepowerplantincommunity“B,”and
● Step‐upfrom480VACto7.2/12.47kVACincommunity“B.”
Thefollowingadditionalassumptionshavebeenmade:
● Bothloadpathsincludeasingle480Vto7.2/12.47kVACtransformer;thecomparativeanalysisdoesnotneedtoconsiderlossesinthistransformer.
● IntertielinelossesarebasedontheoperatingvoltagesandconductorsdescribedinAppendixCforeachintertieconfiguration.
● TwodifferentHVDCconverterefficiencieswereusedtocharacterizetherangeofcomparativeeconomicsforHVDCinterties:
● TheRUS‐basedHVDCintertiecaseusesaconverterefficiencyof96.2%,whichistheefficiencypublishedbyPrincetonPowerSystems,Inc.(PPS)fortheprototypeconverterat50%load(seeAppendixF).
● TheAlaska‐specificHVDCintertiecaseusesahigherconverterefficiencyof97.2%.Thishypotheticalefficiencyresultsinimprovedcomparativeeconomicperformance.
● Transmissionsystemlossesarevaluedbasedontheavoidedcostoffuel.Allotherutilitycostsareassumedtobefixedandnotaffectedbytransmissionsystemlosses.
B.3.3 Operation,Maintenance,andRepairAssumptions
Anannualbudgetof$7,500to$12,300perconverterisprovidedformaintenance,repair,andscheduledcomponentsreplacement.ForHVDCinterties,the$12,300figureisusedfortheRUS‐basedHVDCintertiecase,and$7,500isusedfortheAlaska‐specificHVDCintertiecase.The$7,500perconverter
Page 87
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-13
maintenance,repair,andreplacementbudgetisbasedontheexpectedlifeandreplacementcostofmajorcomponents.Thesecomponentsincludethepowerelectronicsboards,controller,andothermajoritemsthatareexpectedtorequirereplacementduringthe20‐yearlifeofthesystem.SeeAppendixFfordetailsonconvertercomponentlifeandreplacementcosts.
Anannualmaintenanceandrepairbudgetof$1,500permileisassumedforallthreeoverheadintertieconfigurations.
B.3.4 EconomicAssumptions
Adiscountrateof3%hasbeenappliedtobringfuturecashflows(linelosses;OperationandMaintenance,Repair,Replacement,andRehabilitation[OMR&R]costs)topresentvalues.Forpurposesofthiscomparativeanalysis,aprojectlifeof20yearsisusedforallinterties,andnosalvagevalue,disposal,orreplacementcostareconsideredattheendofthe20‐yearlife.
B.3.5 InstalledCostAssumptions
TherangeofinstalledcostsdevelopedfortheconverterstationsinSectionB.5wasusedforthecomparativeeconomicanalysis.ForHVDCinterties,aninstalledcostof$1,040,000perstationisusedfortheRUS‐basedHVDCintertiecase,and$580,000isusedfortheAlaska‐specificHVDCintertiecase
Therangeofinstalledcostsforthethreeintertieconfigurationsarebasedontheestimatedintertiecostspresentedinthefollowingsectionsofthisappendix.
Page 88
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-14
B.4 CASESTUDIES
Thecasestudiesinthissectionprovideproject‐specificexamplesoftheexpectedcostsandresultingbenefitsofusingHVDCsystemstointerconnectcommunitiesandresources.Thesecasestudiesrelyonexistinginformationregardingtheproposedintertieroutes,loads,andrelatedprojectinformation.
TableB‐2summarizesthecasestudiesconsideredinthissection.
Table B-2 Summary of Case Studies
HVDCIntertieCaseStudy
TransmissionCircuit
IntertieType
HVDCIntertieCost
Estimate1
ACIntertieCost
Estimate1
EstimatedHVDCSavings1
PercentCapitalCost
Savings
GreensCreek–Hoonah
5‐MWmonopolarHVDCcircuitwithseareturn2
SubmarineCable
$22.2million $49million
$26.8million 55%
Nome–PilgrimHotSprings
5MWbipolarHVDCcircuit
OverheadLine
$25.7million
$36.3million
$10.6million 29%
Notes:
1. Allcostestimatesarepresentedin2012dollars.
2. Thecasestudyprovidesasubmarineandoverheadintertiecapacityof5MW,andconverterstationcapacityof2MW.ThisprovidesamplemarginforloadgrowthinHoonah.Theconverterstationcapacitycanbeupgradedas‐neededin500kWincrementsupto5MW.
B.4.1 Green’sCreek–HoonahCaseStudy
AnintertiebetweenGreensCreek,ontheAlaskaElectricLightandPower,Inc.(AEL&P)gridthatservesJuneau,andthevillageofHoonah,anisolatedmicro‐gridoperatedbytheInsidePassageElectricCooperative,Inc.(IPEC)hasbeenunderconsiderationforoveradecade.AEL&PandIPEChavecompletedextensivestudyanddesignworkonthisintertie.Studiesidentifieda25‐mile‐longACsubmarinecableandapproximately4milesofoverheadlinenearHoonahasthemosteconomicalmeanstocompletethisinterconnection.24TheproposedintertierouteisshownonFigureB‐3.
Asthedevelopmentofthisprojectcontinued,thecostsoftheACsubmarinecablehaveescalated,untiltheprojectwasfinallyputonholdduetoitsexcessivecost.Hoonahiscurrentlyexploringlocalhydropowerresourcestoreduceitsenergycostsbutcontinuestoviewanintertieasthebestlong‐termsolutionforitsenergyneeds.
ThisHVDCsystemrepresentsatechnologicaladvancethatcanreducethecostoftheGreensCreek–HoonahintertieandincreaseitseconomicfeasibilityascomparedwithHoonah’sotherenergyoptions.Thefollowingsubsectionsofthiscasestudyprovideahigh‐levelanalysisofthemeritsofanHVDCintertieforHoonah.
24(PowerEngineers,2004)
Page 89
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-15
Forpurposesofthiscasestudy,a5‐MWmonopolarHVDCtransmissioncircuitwithseareturnwasselectedtoconnectHoonahwithGreen’sCreek.Thiscircuitconsistsof25milesofsubmarinecableand4milesofoverheadline.Amonopolarcircuitwasselectedbecauseitisexpectedtobetheleast‐costintertiesolutionbetweenHoonahandGreen’sCreek.Otherpotentialconfigurations,suchasabipolarHVDCcircuitutilizingtwosingle‐conductorcables,wouldbemoreexpensivethanthemonopolardesignselected.
Theestimatedcapitalcostsincludea5MWtransmissioncircuit(submarinecableandoverheadline),and2MWconverterstationsatHoonahandGreen’sCreek.Theconverterstationscanbeupgradedto5MWbyadding500kWconvertermodulesasHoonah’sloadincreases.IfHoonah’sloadgrowsbeyond5MW,asecondsubmarinecablecanbeinstalledtoprovidea10MWbipolartransmissionsystem.
Figure B-3 Greens Creek – Hoonah Intertie Route
Page 90
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-16
B.4.1.1 ConceptualDesignBasis
B.4.1.1.1 Load
Hoonah’sannualkWhgenerationisapproximately5,000to5,500megawatt‐hours(MWh).ThepeakloadinHoonahisestimatedat1,200kW.25Aninitialintertiepowercapacityof2,000kWwouldserve100%ofthecommunity’sexistingneedsandprovidea67%marginforfutureloadgrowth(forhandlingpeakload).
B.4.1.1.2 ConceptualIntertieDesign
AmonopolarHVDCintertiecircuitwithsea‐returnisconsideredfortheconceptualdesignoftheGreensCreek–Hoonahintertie.Theintertiehasaninitialcapacityof2,000kW,buttheproposedsubmarinecablecanbeoperatedat5,000kWbyinstallingadditionalmodularpowerconvertersandrelatedupgradesateitherendoftheHVDCsystem.Ahigher‐capacityupgradeto10MWispossiblethroughfurtherconverterstationexpansionandinstallationofasecondcabletoformabipolarHVDCsystem.TheinitialHVDCsystemwouldconsistofthefollowingmajorcomponents:
● AnHVDCconverterstationatHawkInletontheGreensCreekendoftheintertiewitharatedcapacityof2,000kW.Thisstationwouldrequirea69‐kVto480‐volt(V)step‐downtransformer,four500‐kWHVDCconvertermodules,aseareturnelectroderatedfor40amperesofcurrent,andassociatedcontrolsandprotectiveequipment.
● 25milesofmonopolarHVDCsubmarinecable.Thiscablewouldhavearatedcapacityof5MWat50kVDC(100amperes).Thiscablewouldincludea35squaremillimeter(mm2)copperconductor,across‐linkedpolyethylenedielectric,anextrudedleadalloysheath,andtwolayersofcounter‐laidgalvanizedsteelarmorwire.26Afiber‐opticbundleisassumedtobeincludedeitherinthecableconstructionorwithinoneofthearmorwirepositionstofacilitatebroadbandcommunications.
● AsubmarinecablelandingstationatSpasskiBaynearHoonah.ThisstationwouldhousetheshoreendofthesubmarinecableandtransitiontoanoverheadHVDCconductor.Thestationwouldalsoincludeasecondsea‐returnelectrodetocompletethesea‐returncircuit.
● A3.5‐mileoverheadmonopolarHVDCtransmissionlinewithmetallicreturnfromSpasskiBaytotheexistingHoonahpowerhouse.Thistwo‐wireoverheadlinewouldhaveonewireat+50kVDCandthesecondwireclosetoearthpotential.
● Asecond2,000‐kWHVDCconverterstationadjacenttotheexistingHoonahpowerhouse.Thisstationwouldhousethefour500‐kWHVDCpowerconvertersandanACtransformertoconverterthe480VACoutputto4,160VACtointerfacewiththepowerplantbusvoltage.
25AEA,2010a;AEA,2010b26SeeFigure2inAttachmentD‐1toAppendixDofthisreport.
Page 91
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-17
B.4.1.2 EconomicAnalysis
TableB‐3presentstheeconomicanalysisfortheGreensCreek–Hoonahintertiealternatives.TheestimatedinstalledcostfortheHVDCintertieis$22.2million,ascomparedtothecostof$49millionforaconventionalACintertie.TheACintertiecostestimateisbasedonthe2009estimatedcostof$37.5million27adjustedto2012dollars.
Table B-3 Estimated Cost for an Greens Creek – Hoonah HVDC Intertie
CostItem EstimatedCost
PreconstructionRight‐of‐wayacquisition,engineering,survey,permitting $1,600,000
Administration/Management $900,000
HVDCConverterStations(powerconverters,seaelectrodes,enclosures,ACandDCsidestationequipment) $2,700,000
SubmarineCableSupplyandInstallation $12,400,000
OverheadHVDCLine:SpaaskiBaytoHoonah $900,000
Contingency(onentireproject,25%)1 $3,700,000
TotalEstimatedCost $22,200,000
Notes:1.Acontingencyof25%isappliedtothecostsdevelopedforthisprojectbasedontheuncertaintiesassociatedwiththeproject.Asignificantamountofworkhasalreadybeendonetocharacterizethebathymetryandseafloorconditionsalongtheproposedcableroute.
27IPEC,2009.
Page 92
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-18
TableB‐4presentsestimatedbenefit‐costratiosfortheGreensCreek–Hoonahintertieunderseveralloadgrowthscenarios.ThisanalysisindicatesacleareconomicadvantagetoanHVDCintertiebasedonreasonableloadgrowthforecastsforHoonah.
Table B-4 Estimated Benefit-Cost Ratio of Greens Creek – Hoonah HVDC Intertie
ItemLoadGrowthScenario
ExistingLoad 165%Growth 200%Growth6
AnnualHoonahEnergyGeneration(kWh/yr)1 5,150,000 8,500,000 9,780,000
AEL&PAvoidedCostofEnergy(Juneau)2 $0.06perkWh
IPECAvoidedCostofEnergy(Hoonah)1 $0.20perkWh
IntertieOutageRate3 2%
AnnualHoonahSavings4 $707,000 $1,170,000 $1,340,000
IPECOperation,Maintenance,Repair,ReplacementandRehabilitation(OMR&R)AnnualCosts5 $90,000 $90,000 $100,000
NetAnnualSavings(Cost) $617,000 $1,150,000 $1,340,000
IntertieLifeandDiscountRate 30years,3%
PresentWorthofAnnualSavings(Costs) $12,070,000 $21,090,000 $24,500,000
EstimatedInstalledCost $22,200,000 $22,200,000 $22.200,000
EstimatedBenefit‐CostRatio 0.54 0.95 1.10
Notes:
1. BasedonPowerCostEqualization(PCE)reportsfor2007through2009(AEA,2010a).
2. ApproximateAEL&Penergycost.IPEChascapacity,sonodemandorcapacitychargesareincluded.
3. Assumedvalue.
4. AnnualsavingsarebasedonthedifferentialcostofenergyanddonotconsidereconomicbenefitsinHoonahfromlowercostenergy,oreffectstoAEL&Pofincreasedenergysales.
5. IPEC’sestimatedoperations,maintenance,repair,androutinereplacementcostsincludecostsfortheconverterstations,savingsfromdecreasedoperationandoverhaulofthedieselpowerplantinHoonah,andaone‐timecablerepaireventoverthe30‐yearanalysisperiod.
6. Hoonah’speakloadsundera200%loadgrowthscenariowouldexceedthe2‐MWcapacityoftheintertieconverterstations.Intertiethroughputisreducedby5%toreflectdieselgenerationinHoonah.
Page 93
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-19
B.4.2 PilgrimHotSprings–Nome
PilgrimHotSpringsisageothermalresourcelocatedapproximately60milesnorthofNome.IthasbeenproposedasapowersourcetoreduceNome’srelianceondieselfuelforelectricalgeneration.ACEPiscurrentlystudyingthePilgrimHotSpringsgeothermalresourcetobettercharacterizetheresource’spotentialforpowergenerationandotherapplications.ForpurposesofsizingthetransmissionlinefromPilgrimHotSprings,anelectricalgeneratingcapacityandtransmissioncapacityof5MWisassumed,basedonconversationswithACEP’smanagerforthePilgrimHotSpringsassessmentproject.28TheproposedtransmissionrouteisshownonFigureB‐4.
AbipolarHVDCcircuitusingoverheadlineswasselectedfortheHVDCintertie.Thebipolarconfigurationwasselectedbecauseitprovidesincreasedreliabilitycomparedtoamonopolarlineatareasonableadditionalcost.
ConceptualpowerlinecostsforoverheadACandHVDCintertieswereestimatedtoevaluatethebenefitsofconnectingPilgrimHotSpringstoNomeusinganHVDCintertie.ThecostestimatesindicatethatanHVDCtransmissionlinewouldcost29%lessthananACtransmissionline.
28PersonalcommunicationwithMarcusMager,2012.
Page 94
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-20
Figure B-4 Prospective Transmission Route from Pilgrim Hot Springs to Nome
B.4.2.1 ConceptualDesignBasis
Aroutingstudywasnotperformedaspartofthiscasestudy.Theintertierouteisassumedtofollowtheapproximately70‐mileroadcorridorfromNometoPilgrimHotSprings.Thisisassumedtobetheleast‐costrouteforthepowerlines,astheroadcanbeusedtosupporttheconstructionandlong‐termmaintenanceoftheline.Aroutingstudymayidentifyotherroutesthataremorefavorableduetogeotechnical,landstatus,environmental,orotherfactors.
Forthisanalysis,thetransmissionroutedistanceisassumedtobe60miles.
Page 95
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-21
B.4.2.1.1 Load
Nome’saverageannualelectricityusageisapproximately3,500kW,andmonthlypeakdemandisbetween4and10MW.TheassumedsizeofthePilgrimHotSpringsgeothermalpowerplantisassumedtobe5MW.Theintertieisthereforeassumedtohaveacapacityof5MWandoperateatbetween2and5MW,dependingoninstantaneousdemandinNome.
B.4.2.1.2 ConceptualACIntertieDesign
TheconceptualdesignfortheACintertieisathree‐wire69‐kVACoverheadlineseton45‐footwoodpoleswitharulingspanof400feet.Allpolesareassumedtobefastenedtosteelpilefoundationsformomentsupportandtoresistfrostjackingforces.
TheACtransmissionsystemwouldconsistofthefollowingmajorcomponents:
● A5‐MWgeothermalpowerplantatPilgrimHotSpringsgeneratingat4,160V.
● Asubstationandswitchyardtoincreasevoltagefrom4,160Vto69kV.
● Anapproximately60‐mile‐longoverheadintertiefromPilgrimHotSpringstoNome.
● AsubstationandswitchyardinNometoisolateNomefromthetransmissionlineandstepdownthevoltagefrom69kVto12.47kVfordistributioninNome.
B.4.2.1.3 ConceptualHVDCIntertieDesign
TheconceptualdesignfortheHVDCintertieisabipolarcircuitoperatingat+50and–50kVDC.Thetwocircuitswouldbesupportedonaguyedglass‐fiber‐reinforcedpolymer(GFRP)polefittedwithacrossarmandsuspensioninsulators.Arulingspanof1,000feetisassumed.ThedesignissimilartothatshownonFigureC‐9.
TheHVDCtransmissionsystemwouldconsistofthefollowingmajorcomponents:
● A5‐MWgeothermalpowerplantatPilgrimHotSpringsgeneratingat480V.Itmaybepreferabletoinsteadgenerateat4,160Vandhaveastep‐downtransformertothe480Vinterfacevoltagetothepowerconverters.
● AbipolarHVDCconverterstationconsistingoftwobanksoffive500‐kWpowerconverters.Eachbankwouldforma2.5‐MWpoleonthebipolartransmissionsystem.
● Anapproximately60‐mile‐longbipolarHVDCtransmissionlinefromPilgrimHotSpringstoNome.
● AsecondbipolarHVDCconverterstationinNome.
● AnACtransformertostepuptheACoutputfromtheconvertersfrom480Vupto7.2/12.47kVfordistributioninNome.
Page 96
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-22
B.4.2.2 EconomicAnalysis
TableB‐5presentstheeconomicanalysisforthePilgrimHotSprings–Nomeintertiealternatives.TheestimatedinstalledcostfortheHVDCintertiealternativeis$25.7million,ascomparedtothecostof$36.3millionforaconventionalACintertie.
NoinformationisavailablefortheinstalledcostofageothermalpowerplantatPilgrimHotSpringsorthecostoftheenergyitwouldgenerate,soabenefit‐costratiooftheintertiealternativeswasnotevaluated.
Table B-5 Estimated Installed Cost for a 5-MW Pilgrim Hot Springs – Nome Intertie
CostItemEstimatedInstalledCostforBipolarHVDCIntertie
EstimatedInstalledCostforACIntertie
EstimatedHVDCSavings
PercentCostSavings
PreconstructionActivities(right‐ofwayacquisition,design,survey,permitting)
$3,400,000 $3,400,000 ‐ ‐
Administration/Management $1,000,000 $1,300,000 ‐ ‐
ConverterStationConstruction $4,600,000 $3,000,000 ‐ ‐
OverheadIntertieConstruction $10,800,000 $20,200,000 ‐ ‐
Contingency(30%)1 $5,900,000 $8,400,000 ‐ ‐
TotalEstimatedCost $25,700,000 $36,300,000 $10,600,000 29%
Note:
1. A30%contingencywasappliedtothecostsforthisprojectbecausenoinformationwasavailableforthetransmissionroute.Thislackofdatacreatesrisksduetofactorssuchaslandavailability,geotechnicalconditions,structural(windandice)loadings,andenvironmental(bird,wildlife,andaesthetics)factors.Someoftheserisksaremitigatedbytheuseofcostdatafortherobustconceptualdesigns(i.e.,Alaska‐specificconstruction)usedfortheHVDCsystem.TheAlaska‐specificconceptualdesignisassumedtobeadequatefortheexpectedgeotechnicalandstructuralconditionsalongtheroute.Environmentalandlandavailabilityissues,whichcouldrequirealongerrouteordeparturefromtheroadcorridor,poserelativelygreaterrisksthanlinedesignconsiderations.Thenetresultofthesefactorsresultsinthe30%contingencyusedforthecasestudyeconomics.
Page 97
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-23
B.5 DETAILEDHVDCINTERTIECOSTINFORMATION
B.5.1 OverheadIntertieCostDetail
ThisreportconsidersdifferentoverheaddesignconceptsforHVDCinterties.Thissectionpresentsarangeofestimatedcostsfortheseconcepts.
Thetwo‐wiremonopolarintertieadaptedfromstandardRUSpracticeisestimatedtohavethehighestinstalledcost.Incontrast,themonopolarSWERintertiebasedonAlaska‐specificdesignconceptsisestimatedtohavethelowestinstalledcost.
TableB‐6presentsabreakdownoftheestimatedinstalledcostsfor25‐mileoverheadintertiesinruralAlaskausingthedesigncasesandconceptspresentedinAppendixC.
Page 98
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-24
Table B-6 Estimated Cost for a 25-mile Overhead HVDC Intertie
CostItemMonopolarSWER,AlaskaSpecificConstruction
Two‐WireMonopolarHVDC,RUS–BasedConstruction
Per‐MileCost ProjectCost Per‐MileCost ProjectCost
PreconstructionRight‐of‐wayacquisition,design,survey,permitting $58,000 $1,450,000 $56,000 $1,400,000
Administration/Management $13,000 $325,000 $17,000 $425,000
Materials(intertieonly) $48,000 $1,200,000 $47,000 $1,175,000
ConverterStations(onper‐milebasis) $62,000 $1,550,000 $62,000 $1,550,000
Shipping $15,000 $375,000 $25,000 $625,000
Mobilization/Demobilization $37,000 $925,000 $94,000 $2,350,000
Labor $67,000 $1,675,000 $71,000 $1,775,000
TotalCost $300,000 $7,500,000 $372,000 $9,300,000
Note:Lineitemcostsincludeanembedded25%contingency.
Page 99
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-25
B.5.2 SubmarineCableIntertieCostDetail
Anumberofsite‐specificfactorsinfluencethecostofsubmarinecableapplicationsforHVDCapplicationsinAlaska.Thesearethefollowing:
● CablelayingvesselsarespecializedequipmentthatmustbemobilizedtoAlaska.MobilizingthesevesselstoAlaskaiscostlyandprojectdependant.Mobilizationcostsresultinshortsubmarineintertiesbeingsignificantlymoreexpensiveonaper‐milebasisthanlongsubmarineinterties.
● Marinetrafficinfluencessubmarineintertiecosts.Shallowercableroutesmustconsidercommercialfishingactivity,anchoring,andrelatedmarinetrafficthatmayposeahazardtothecable.
● Theseafloorconditionsalongthecableroutealsoinfluencecosts.Steepslopes,ruggedexposedrock,orunstableslopeswilltendtoincreasecostsorprojectrisk.
● Thedepthofthecableroutewillinfluencecosts.Deeperroutesrequirestronger,heavier,andmorecostlycables,whichinturncanrequirelarger,moreexpensivecablelayingvessels.
Asaresult,agenericper‐milecostoflow‐powersubmarinecablesisnotmeaningfulwithoutconsiderationoftheproject‐specificfactors.
B.5.3 UndergroundCableIntertieCostDetail
Anumberofsite‐specificfactorswillstronglyinfluencethetechnicalfeasibilityandcostofundergroundcableapplicationsforlow‐powerHVDCapplicationsinAlaska.Thesearethefollowing:
● Presenceofgroundsusceptibletofrostcrackingorpolygonalcracking.Thesegroundcrackscanimposelargetensionforcesoncablesandcausemechanicalfailureofthecable,resultinginelectricalfaults.
● Geotechnicalconditionsalongthecableroutewillinfluencethecostofcableinstallation.
● Steepterrainorotherlocalconditionsmaypreventuseofundergroundcable.
EstimatedcostsforHVDCintertiesusingundergroundcablesarepresentedinTableB‐7.
Page 100
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-26
Table B-7 Estimated Costs for a 25-mile Underground HVDC Intertie
CostItem EstimatedPer‐MileCost
PreconstructionRight‐of‐wayacquisition,design,survey,permitting $45,000
Administration/Management $13,000
Materials(intertieonly) $80,000
Converterstations(onpermilebasis) $62,000
Shipping $20,000
Mobilization/Demobilization $10,000
Labor $20,000
TotalCost $250,000
Note:Lineitemcostsincludeanembedded25%contingency.
TheestimatedcostsinTableB‐7arebasedonthefollowingassumptions:
● Terrainandconditionsaresuitableforuseofatrack‐mountedtrenchersuchasaDitchWitchRT115Quad,whichcancutatrenchthroughfrozengroundduringthewintermonthsovermostterrain;
● 1/0fullconcentricneutraljacketed35‐kVACcablewithethylenepropylenerubber(EPR)dielectricina2‐inchduct;
● Awaterblockingantifreezegelcompoundisused;
● Afiber‐opticcableinductisinstalledinthesametrench;
● Limitedbrushingisnecessarytocleartheroute;
● Cablereelsarespottedalongthelinewithahelicopter;and
● Thecableinstallationdepthisaminimumof18inches.
B.5.4 ConverterStationCostDetail
TheHVDCconverterstationswillincludethemajorcomponents:
● HVDCpowerconverters;
● Converterenclosures,whichmayconsistofdedicatedenclosuresoruseofanexistingbuilding,suchasanexistingpowerplant;
● ProtectionandswitchingequipmentontheACandHVDCsidesoftheconverters;
● ACtransformers,dependingontheACinterfacevoltageandwiring;and
● Groundingstations,includingthegroundconductorfromtheconverterstationtothegroundingstation.
Theestimatedinstalledcomponentcostsfora1‐MWmonopolarHVDCconverterstationispresentedinTableB‐8.Therangeofcostsisbasedonthepresenceofexistinginfrastructureandproject‐specificconditions.
Page 101
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-27
Table B-8 1-MW HVDC Converter Station Cost Estimate
CostItem EstimatedCost
1‐MWHVDCPowerConverter $220,000to$280,000
ConverterEnclosure $40,000to$160,000
AC‐SideandHVDC‐SideProtectiveandSwitchingEquipment $100,000to$190,000
1‐megavoltamperes(MVA)ACTransformer(7.2/12.4kV–480V) $0to$30,000
GroundingStation $100,000to$170,000
Contingency(25%) $120,000to$210,000
Total,1‐MWHVDCConverterStation $580,000to$1,040,000
B.5.4.1 ConverterCostDetail
BasedonPhaseIIdevelopmentefforts,PPSestimatesthatthecommercialcostoftheHVDCpowerconverterswillbe$250,000+/‐10%per1‐MWpowerconverter.PPSstatesthatasmanufacturingvolumesincrease,theper‐convertercostshoulddecrease.PPSforecastsa5%to10%discountat10unitsanda20%to30%discountat100units.SeeAppendixFforamoredetaileddiscussionofconvertercosts.
B.5.4.2 ConverterEnclosureCostDetail
Estimatedcostsassumethatamodular,prefabricatedenclosurewillbesenttothecommunitywiththetwo500‐kWpowerconverterunitsalreadyinstalled.Thisconvertermodulewillthenbesetinplaceonasuitablefoundation.EstimatedcostsarelistedinTableB‐9.
Table B-9 HVDC Converter Enclosure Cost Detail
CostItem EstimatedCost
PowerConverterEnclosure $68,000
Foundation $30,000
Labor $27,000
Shipping $35,000
Total,1‐MWHVDCConverterEnclosure $160,000
Page 102
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-28
IncommunitiesthatwillbeprimarilyservedbyanHVDCintertie,itmaybeappropriatetolocatetheconvertersinsidetheexistingpowerhouseorothersuitableexistingstructure.Thiswouldhavethefollowingadvantages:
● Theexistingpowerhousewouldalreadyhaveastep‐downtransformersizedforthefullcommunityload,
● Wasteheatfromtheconverterswouldprovideallorpartoftheheatforthepowerplantbuilding,and
● Thiswouldachieveprojectcostreductionbyeliminatingtheneedforadedicatedconverterenclosureandtheneedtopurchaseorleaselandtositetheconverter.
B.5.4.3 SwitchgearandSwitchyardEquipmentCostDetail
SwitchgearisrequiredontheACsideoftheconvertersforisolationandprotectionpurposes.Dependingonthedesireddegreeofsystemautomation,theswitchgearmayalsointerfacebetweentheconvertercontrolsandthepowerplantcontrolstoallowremotedispatchofgeneratorsandtheHVDCpowerconverter.
Similarisolation,protection,andmonitoringequipmentisneededintheHVDCswitchyardontheHVDCsideoftheconverter.Ataminimum,manualdisconnectswitches(nonloadbreak),surgearrestors,andfusesarerequired.CurrentandvoltagesensorsareneededontheHVDClineaswell.
EstimatedswitchgearandswitchyardcostsarepresentedinTableB‐10.
Table B-10 Switchgear and Switchyard Cost Detail
CostItem EstimatedCost
ACSwitchgearSection(Fuses,DisconnectSwitches[loadbreak]) $25,000to$35,000
HVDCManualDisconnectSwitch(nonloadbreak) $2,000to$20,000
HVDCSurgeArrestor $10,000to$15,000
HVDCFuse $2,000to$8,000
ACandDCSensors $30,000to$48,000
OtherMaterials $12,000to$16,000
Shipping $5,000to$18,000
Labor $14,000to$20,000
Total,1‐MWHVDCConverterStationSwitchgearandSwitchyard $100,000to$190,000
Page 103
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-29
B.5.4.4 ACTransformerCostDetail
Thegridinterfaceonthepowerconvertersisthree‐phase480‐VAC.Incommunitieswheretheconverterisconnecteddirectlytothe480‐Vpowerplantbuss,noadditionaltransformerisrequired.Incommunitieswheretheconverterconnectstothelocaldistributiongrid,astep‐uptransformerisrequired.Thetransformerisassumedtobeathree‐phase480/12.47kVtransformer.
B.5.4.5 GroundingStationCostDetail
AgroundingstationwillneedtobeprovidedateachHVDCconverterstation,regardlessoftheHVDCcircuitconfiguration.Theconceptualdesignofa1‐MW50kVDCgroundingstationispresentedinAppendixE.EstimatedcostsforthisstationarepresentedinTableB‐11,andinclude1mileofoverheadlinebetweentheconverterstationandthegroundingstation.
Costsforgroundingstationswilldependonthelocalgeotechnicalconditions,thedistancebetweentheconverterandgroundingstations,andotherfactors.
Table B-11 HVDC Grounding Station Cost Detail
CostItem ConceptualCost
SiteInvestigations $26,000to$33,000
Materials $25,000to$45,000
Labor $34,000to$46,000
Equipment $7,000to$12,000
Shipping $8,000to$34,000
Total,1‐MWHVDCGroundingStation $100,000to$170,000
Page 104
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-30
B.6 DETAILEDACINTERTIECOSTINFORMATION
ThissectionpresentscostbaselinesforremoteAlaskaACintertiestoallowcomparisontotheHVDCalternativespresentedinthisreport.CostbaselinesforACintertieprojectsweredevelopedusingtwomethods.Thefirstmethodwastodevelopconceptualcostestimatesconsideringunitcostsforlabor,materials,mobilization,etc.Thesecondmethodwastoreview,whereavailable,theactualcostsofrecentrelevantACintertieprojectsinAlaska.Forbothmethods,twotypesofintertieswereanalyzed:
1. OverheadintertielinesinarcticandsubarcticregionsofwesternAlaska.Theseregionspresentsomeofthegreatestgeotechnicalandlogisticalchallenges;therefore,theytendtohavethehighestinstalledcostsforoverheadinterties.
2. SubmarinecableintertiesinruralAlaska.FormanypartsofAlaska,andinparticularthesoutheast,submarinecablesaretheonlyviablemeansofbuildingapowerintertie.
ThecostbaselinesaresummarizedinTableB‐12.
Table B-12 Cost Baselines for Remote Alaska AC Intertie Construction
TypeofACElectricIntertie1CostBaselineby
UnitCost/QuantityMethodCostBaselinefromRecent
ProjectExperience
OverheadInterties2 $440,000permile $450,000permile+/‐50%
SubmarineCableInterties3 N/A $1,300,000permile+/‐35%
Notes:1. Intertiepowercapacitywillaffectcost.Seesubsequentnotesforthespecifictypesofintertiesconsideredtodevelop
theseconceptualcosts.2. IntertiesarestandardRUSthree‐phase14.4/24.9kVconstruction,usingsteelpilefoundations.3. Intertiesaresingle‐bundledthree‐conductorarmoredcable.
Page 105
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-31
B.6.1 CostBaselinesforOverheadACInterties
B.6.1.1 CostBaselineforOverheadACIntertiesUsingUnitCostsandQuantities
AcostbaselinefortypicalACtransmissionsystemshasbeenestimatedfor10‐mileand25‐mileintertieconcepts.Theseconceptsarebasedonastandardfour‐wirethree‐phase14.4/24.9kVRUSpowerlineusingdrivensteelpilefoundations.TheestimatedinstalledcostsarepresentedinTableB‐13.
Table B-13 Estimated Costs for Overhead AC Interties
CostItem10‐MileIntertie 25‐Mileintertie
Per‐MileCost
ProjectCostPer‐MileCost
ProjectCost
PreconstructionRight‐of‐wayacquisition,design,survey,permitting
$61,000 $610,000 $39,000 $975,000
Administration/Management $18,000 $180,000 $18,000 $425,000
Materials $71,000 $710,000 $71,000 $1,775,000
Shipping $36,000 $360,000 $33,000 $825,000
Mobilization/Demobilization $136,000 $1,360,000 $125,000 $3,125,000
Labor $111,000 $1,110,000 $111,000 $2,675,000
TotalCost $440,000 $4,400,000 $397,000 $9,875,000
Theper‐milecostofoverheadACintertiesdecreasesastheintertiegetslonger.Thisisinfluencedbythefollowingfactors:
● Thescopeandcomplexityofenvironmental,right‐of‐way,design,andpermittingissuesfortheproject.
● Thequalityofaccesscorridorsalongtheintertieroute.Theestimatedcostsassumethatper‐milelaborcostsareindependentofintertielength.
● Theconstructionplanandschedule.Theestimatedcostsassumethatper‐milemobilization/demobilizationcostsdecreaseslightlywithincreasingintertielength.
Thisreportfindsthatper‐milecostsfortypicaloverheadACintertiesdecreaseapproximately10%astheintertielengthincreasesfrom10to25miles.Further,anadditionaldecreaseof5%occursfrom25to50miles.Costsareconstantonaper‐milebasisfrom50to100miles.
Page 106
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-32
B.6.1.2 CostBaselineforOverheadACIntertiesUsingComparableProjectCosts
ConstructioncostdatacompiledforsevenremoteoverheadintertielinesbuiltinwesternAlaskaoverthepast20yearsarepresentedinTableB‐14.ThelinesselectedareconsideredrepresentativeofthemostdifficultlogisticalandgeotechnicalconditionscommoninAlaska.BasedonTableB‐14,theconceptualper‐milecostforaremoteAlaskaoverheadACintertieis$450,000permile,+/‐50%(2012$).
ThecostdataarepresentedasageneralcostbaselineforremoteAlaskaoverheadinterties.
Table B-14 Installed Costs of Recent Remote Alaska Overhead AC Interties
IntertieProjectInstalledCost1
YearBuilt
Length
(miles)Per‐MileCost(2012$)2
Kobuk–Shungnak3 $1.1M 1991 11 $276,500
ToksookBay–Tununak4,5 $2.0M 2005 6.6 $440,200
Nunapitchuk–OldKasigluk–AkulaHts.5,6 $1.9M 2006 4.2 $594,400
ToksookBay–Nightmute7,8 $6.9M 2009 18 $495,800
Bethel–Napakiak5,9 $3.1M 2010 10.5 $344,400
BrevigMission–Teller10 $4.7M 2011 6.8 $730,200
Emmonak–Alakanuk11 $2.9M 2011 11 $267,300
AverageCostperMile,2012Dollars: $449,800
AverageCostperMile,(ExcludingHighestandLowest‐CostProjects): $430,300
Notes:1. Installedcostsareinnominaldollarsatthetimeofconstruction.Duetothelimiteddetailandvarietyofsourcesforcost
data,itisnotalwayspossibletodiscernifcostsforagivenprojectincludepreconstruction,construction,sharedmobilizationwithseparatebutconcurrentprojects,andsimilarcomplicatingfactors.Adjustingfortheseunknownfactorsmayincreaseordecreasetheprojectcostthatispresentedinthetable.
2. Projectcostsareadjustedto2012dollarsusingacustomescalatorbasedonAlaskalaborcostsandcommoditypricesrelevanttooverheadintertieconstruction.
3. Estimatedcostfortheproject.TheprojectconsistedofreplacinganACSWERintertiewithaconventionalRUSACintertie(Petrie,personalcommunication,2012).
4. TheprojectconsistedofanewoverheadACintertie(DenaliCommission,2008b).5. EntireintertiewassetonH‐pileorroundpilefoundations(DenaliCommission,2008a,2008b,and2010).6. TheprojectconsistedofreplacinganexistingoverheadACintertiewithanewoverheadACintertie.Thecostwas
reducedby$300,000forstep‐downtransformersforservicesalongtheintertieroutethatarenotpartofthe“intertie”cost(DenaliCommission,2008a)
7. TheprojectconsistedofanewoverheadACintertie(DenaliCommission,2009).8. Approximately30%ofintertieissetonsteelpilefoundations(DenaliCommission,2009).9. TheprojectconsistedofreplacinganACSWERintertiewithaconventionalRUSACintertie(DenaliCommission,2010).10. TheprojectconsistedofanewACintertieincludingoverhead,underground,andsubmarinecablesegments.Cost
includespreconstructionandbudgetedconstruction(DenaliCommission,2011).11. Thisistheestimatedcostforaproposedintertiebuiltin2011.Theintertieprojectsharedmobilizationcostswith
concurrentinstallationofwindturbinesinEmmonak(AVEC,2008).
Page 107
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-33
B.6.2 CostBaselineforSubmarineCableACInterties
ConstructioncostdatawerecompiledforthreeACsubmarinepowercablesinstalledorproposedinAlaskaoverthepast15years;thesedataarepresentedinTableB‐15.Veryfew“low‐power”ACsubmarinecableshavebeenbuiltinAlaska–thecablesinTableB‐15eachhaveacapacityof10to15MW.Theselineswerereviewedbecausetheyarethesmallestsubmarinecableswithavailablecostdata.Theindicatedconceptualper‐milecostforaACsubmarineintertieinAlaskais$1,300,000permile,+/‐35%(2012$).
Submarinecablecostsareprojectdependentandhaveasignificantcostvariability.Shortcableprojectsinparticularcanbeexpectedtohavesignificantlyhigherper‐milecostduetothefixedmobilizationcostofspecializedcable‐layingvessels.
ThecostdataprovideageneralcostbaselineforremoteAlaskasubmarinepowercables.
Table B-15 Installed Costs of Recent Remote Alaska Submarine Cable Interties
IntertieProjectInstalledCost1
YearBuilt/Proposed
Length(miles)
Per‐MileCost(2012$)2
Haines–Skagway3 $5.86M 1998 15 $880,000
Homer–SouthKatchemakBay5 $2.5M 2001 4.5 $1,200,000
Green’sCreek–Hoonah4 $37.5M 2009 29 $1,700,000
AverageCostperMile,2012Dollars: $1,300,000
Notes:1. Installedcostsareinnominaldollarsatthetimeofconstruction.Duetothelimiteddetailandvarietyofsourcesforcost
data,itisnotalwayspossibletodiscernifcostsforagivenprojectincludepreconstruction,construction,sharedmobilizationwithseparatebutconcurrentprojects,andsimilarcomplicatingfactors.Adjustingfortheseunknownfactorsmayincreaseordecreasetheprojectcostthatispresentedinthetable.
2. Projectcostsareadjustedto2012dollarsusingacustomescalatorbasedonAlaskalaborcostsandcommoditypricesrelevanttopowerlineconstruction.
3. TheHaines‐Skagwaycablehasamaximumdepthof1,500feetandaratedcapacityof15MW(INEEL,1998).4. TheGreen’sCreek–Hoonahcablehasnotbeenbuiltduetoitscost.Installedcostsarethemostrecentestimates
available.Thiscablerouteincludesdepthsto2,600feet.Costsincludeapproximately4milesofoverheadline(IPEC,2009).
5. TheHomer–SouthKatchemakBaycablehasamaximumdepthof600feetandaratedcapacityofapproximately12MW(AJOC,2001).
Page 108
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE B-34
Thispageintentionallyblank.
Page 109
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-1
APPENDIXC
CONCEPTUALDESIGNOF
OVERHEADHVDCINTERTIELINES
Page 110
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-2
Thispageintentionallyblank.
Page 111
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-3
TABLEOFCONTENTS
C.1 INTRODUCTION........................................................................................................................................................7 C.1.1 RURALUTILITIESSERVICE(RUS)DESIGNAPPROACH,MODIFIEDFORHVDCINTERTIES................................7 C.1.2 ALASKA‐SPECIFICDESIGNAPPROACHFORHVDCINTERTIES..................................................................................7
C.2 DESIGNCRITERIAFOROVERHEADINTERTIELINES.............................................................................8 C.2.1 GEOTECHNICALCONDITIONS...........................................................................................................................................8 C.2.2 ENVIRONMENTALLOADS.................................................................................................................................................8
C.3 CONCEPTUALDESIGNOFOVERHEADHVDCTRANSMISSION,RUSSTANDARDPRACTICE10 C.3.1 CONVENTIONALACINTERTIEDESIGN........................................................................................................................10 C.3.2 MONOPOLARSINGLE‐WIRETRANSMISSIONWITHEARTH‐RETURNPATH(SWER),CONVENTIONALLYBUILT
............................................................................................................................................................................................13 C.3.3 MONOPOLARTWO‐WIRETRANSMISSIONWITHMETALLICCONDUCTOR‐RETURNPATH(TWMR),
CONVENTIONALLYBUILT...............................................................................................................................................16 C.3.4 BIPOLARTWO‐WIRETRANSMISSION,CONVENTIONALLYBUILT...........................................................................19
C.4 CONCEPTUALDESIGNOFOVERHEADHVDCTRANSMISSION,ALASKA‐SPECIFICMETHODS22 C.4.1 MONOPOLARSINGLE‐WIRETRANSMISSIONWITHEARTH‐RETURNPATH(SWER,ALASKA‐SPECIFICDESIGN
............................................................................................................................................................................................23 C.4.2 MONOPOLARTWO‐WIRETRANSMISSIONWITHMETALLICCONDUCTOR‐RETURNPATH(TWMR),ALASKA‐
SPECIFICDESIGN.............................................................................................................................................................26 C.4.3 BIPOLARHVDCINTERTIELINE,ALASKASPECIFICDESIGN...................................................................................29 C.4.4 CONCEPTUALDESIGNANALYSIS...................................................................................................................................32 C.4.5 MAINTENANCEMETHODS..............................................................................................................................................33
C.5 CONCEPTUALDESIGNANALYSIS...................................................................................................................35 C.5.1 STRUCTURALDESIGN......................................................................................................................................................35 C.5.2 FOUNDATIONDESIGN.....................................................................................................................................................35 C.5.3 ANALYSISOFTHERMOPROBEPERFORMANCE............................................................................................................35 C.5.4 ELECTRICALDESIGN.......................................................................................................................................................44
C.6 TESTINGOFOVERHEADDESIGNCONCEPTS............................................................................................49 C.6.1 TESTOBJECTIVES............................................................................................................................................................49 C.6.2 TESTSITE.........................................................................................................................................................................49 C.6.3 INSTALLATION..................................................................................................................................................................49 C.6.4 MONITORING....................................................................................................................................................................50
APPENDIXCATTACHMENTS...........................................................................................................................................63 ATTACHMENTC‐1:ZARLINGAEROCONSULTING(ZAE)THERMALANALYSISOFTHERMOPILE.....................................63 ATTACHMENTC‐2:ARCTICFOUNDATIONS,INC.(AFI)SHOPDRAWINGS............................................................................91
Page 112
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-4
Thispageintentionallyblank.
Page 113
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-5
LISTOFTABLES
TableC‐1 ConceptualDesignDataforConventionalACIntertieLine....................................................12
TableC‐2 ConceptualDesignDataforConventionallyBuiltMonopolarSWERHVDCIntertieLine..........................................................................................................................................................................15
TableC‐3 ConceptualDesignDataforConventionallyBuiltMonopolarHVDCwithMetallicReturn..........................................................................................................................................................................18
TableC‐4 ConceptualDesignDataforConventionallyBuiltBipolarHVDCIntertieLine...............21
TableC‐5 ConceptualDesignDataforAlaska‐SpecificMonopolarSWERHVDCIntertieLine....25
TableC‐6 ConceptualDesignDataforAlaska‐SpecificMonopolarMetallic‐ReturnIntertieLine28
TableC‐7 ConceptualDesignDataforAlaska‐SpecificBipolarHVDCIntertieLine..........................31
TableC‐8 SummaryofResultsfromThermoprobeModelingbyZAE....................................................37
Page 114
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-6
LISTOFFIGURES
FigureC‐1 TangentPoleforConventionalACIntertieLine..........................................................................11
FigureC‐2 ConventionalTangentPoleforMonopolarSWERHVDCIntertieLine..............................14
FigureC‐3 ConventionalTangentPoleforMonopolarHVDCwithMetallicReturn...........................17
FigureC‐4 ConventionalTangentPoleforBipolarHVDCIntertieLine...................................................20
FigureC‐5 Alaska‐SpecificTangentPoleforMonopolarSWERHVDCIntertieLine..........................24
FigureC‐6 Alaska‐SpecificTangentPoleforMonopolarMetallic‐ReturnIntertieLine....................27
FigureC‐7 Alaska‐SpecificTangentPoleforBipolarHVDCIntertieLine...............................................30
FigureC‐8 PrototypeMicro‐ThermopileTripodPoleFoundation............................................................38
FigureC‐9 ShopDrawingofPrototypeGFRPPoleBaseAdapterforMicro‐ThermopileFoundation(Sheet1of3)..............................................................................................................................................39
FigureC‐10 ShopDrawingofPrototypeGFRPPoleBaseAdapterforMicro‐ThermopileFoundation(Sheet2of3)..............................................................................................................................................40
FigureC‐11 ShopDrawingofPrototypeGFRPPoleBaseAdapterforMicro‐ThermopileFoundation(Sheet3of3)..............................................................................................................................................41
FigureC‐12 GalvanizedScrewAnchorswith8‐InchFlights...........................................................................43
FigureC‐13 TypicalBipolarHVDCTransmissionLineUsingSuspensionInsulators...........................45
FigureC‐14 TypicalTangentStructureUsingPostInsulators.......................................................................46
FigureC‐15 TypicalAngleStructureUsingSuspensionandPostInsulators...........................................47
FigureC‐16 TypicalTangentStructureUsingSuspensionandPostInsulators......................................48
FigureC‐17 InstallingMicro‐ThermopileforGuyAnchor...............................................................................51
FigureC‐18 SettingMicro‐ThermopileGuyAnchorwithSandSlurryBackfill.......................................52
FigureC‐19 InstallingMicro‐ThermopileforGuyAnchor...............................................................................53
FigureC‐20 Micro‐ThermopilesStagedatFairbanksTestSiteforInstallationofPrototypeFoundations..........................................................................................................................................................................54
FigureC‐21 Micro‐ThermopileTripodforPrototypePoleFoundation.....................................................55
FigureC‐22 InstallingHelicalScrewAnchorforGuyAnchor.........................................................................56
FigureC‐23 GuyAttachedtoMicro‐ThermopileFoundation.........................................................................57
FigureC‐24 AssemblingthePrototypeGFRPPoleSplice.................................................................................58
FigureC‐25 InstalledGFRPPole,Micro‐Thermopiles,andAdapterPlate.................................................59
FigureC‐26 PrototypeGFRPPoleFoundationDuringInstallation..............................................................60
FigureC‐27 PrototypePoleattheFairbanksTestSite......................................................................................61
FigureC‐28 PrototypePoleattheFairbanksTestSite......................................................................................62
Page 115
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-7
C.1 INTRODUCTION
Theconceptualoverheadtransmissionlinedesignalternativespresentedinthisappendixrequiredconsiderationofsite‐specificconditions,codes,utilityandlenderrequirements,constructionmethodologies,standarddesignpractices,andprojecteconomics.
Twoconceptualdesignapproachesforoverheadhigh‐voltagedirectcurrent(HVDC)intertieshavebeenevaluated,eachwithacapacitytosupply1megawatt(MW)at50kilovolts(kV)DC:(1)U.S.DepartmentofAgriculture(USDA)RuralUtilitiesService(RUS)designapproach,modifiedforHVDCinterties;and(2)Alaska‐specificdesignapproachforHVDCinterties.Eachisdescribedbelow.
C.1.1 RuralUtilitiesService(RUS)DesignApproach,ModifiedforHVDCInterties
ThefirstconceptualdesignapproachisbasedontheuseofstructuresthatareconstructedinaccordancewiththeRUSstandardpracticesforconventional12.4/24.9kilovolt(kV)alternatingcurrent(AC)distributionlines.29TheseRUSstandardpracticesarecurrentlyusedtodevelopACintertiesthroughoutAlaskaandarewidelyacceptedbytheutilityindustry.HVDCtransmissionrequiresfewerconductorsthanAC,resultinginreducedloadsonthesupportingstructures.Asaresult,theconceptualdesignsdevelopedwiththeRUSapproachhavelongerrulingspansthantypicalAClines.ThisresultsinfewertransmissionstructuresfortheHVDCintertieandanassociatedcomparativereductioninconstructioncost.
C.1.2 Alaska‐specificDesignApproachforHVDCInterties
ThesecondconceptualdesignapproachtakesthelogisticandtechnicalchallengesofconstructioninruralAlaskaintoconsiderationandfocusesonmethodstoreduceconstructioncostswithoutcompromisingperformanceorlong‐termmaintainability.Thisdesignapproachincorporatescost‐savingfeaturesmadepossiblethroughHVDC‐specificdesignalternatives,materials,andconstructionmethods.DesignfeaturesofthisconceptincludetheuseofguyedcompositestructurestoallowsignificantlylongerrulingspansthanispossiblewithRUSstandardpractice.Thereducednumberofstructures,lesscostlyfoundations,andreducednumberofconductorsallresultinadditionalsavingscomparedwithintertiesbuilttoRUSstandardpractices.
ThefollowingthreeHVDCtransmissioncircuitconfigurationsareconsideredforeachoftheHVDCconceptualdesignapproaches:
● Monopolarsingle‐wiretransmissionwithearth‐returnpath(SWER);
● Monopolartwo‐wiretransmissionwithmetallicconductor‐returnpath(TWMR);
● Bipolartwo‐wiretransmission.
Schematicfiguresareprovidedinthisappendixforeachoftheseconceptualdesigns.Detailedreportsthataddressvarioustechnicalaspectsoftheassumedconditionsandloadingsusedtodeveloptheseconceptualdesignsareprovidedasattachmentstothisappendix.
29 Inthisreport,theterm“RUSstandardpractice”referstooverheadintertielinedesignsbasedonthemethodsandmaterials
presentedinRUSdesignmanualsfortransmissionanddistributionlineconstruction,includingbutnotlimitedto:REA,1982,RUS,1998,2002,2003a,2003b,2003c,and2009.
Page 116
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-8
C.2 DESIGNCRITERIAFOROVERHEADINTERTIELINES
ThefollowingdesigncriteriahasbeendevelopedasabasisfortheconceptualdesignoftheHVDCoverheadintertielines.
C.2.1 GeotechnicalConditions
Basedontheanalysisdescribedbelow,conceptualfoundationdesignalternativesforaguyedpoleutilizethreethermoprobemicropilesforthepolebaseandhelicalanchorsfortheguys.TheconceptualfoundationdesignalternativesarepresentedonFiguresC‐9throughC‐11.Theoverheadsystemtestsiteincludesinstallationofbothoftheseprototypefoundations,aswellasthermoprobemicropilesandscrewanchorstorestraintheguywires.
PolarconsultcontractedwithGolderAssociates,Inc.(Golder)toidentifyandcharacterizethemostcommongeotechnicalconditionsthatposethegreatesttechnicalandeconomicchallengesforruralAlaskaoverheadintertielinesascurrentlydesigned.
Insummary,GolderidentifiedthreeconceptualgeotechnicalconditionsrepresentingthegreatesteconomicchallengeforruralAlaskaoverheadinterties.Thesearesummarizedbelow.
Profile“A”:Icy,“warm”permafrostcomprisedprimarilyoflow‐plasticitymineralsiltbelowanactivelayerwithhigherorganiccontent.Thepermafrosttemperatureintheupper15feetbeneaththeactivelayerwouldhaveamaximumtemperature(occurringinlateautumn)of31.0to31.5°F.Theactivelayerisassumedtobeapproximately3.5feetthick,consistingoforganicsoilsandsurfacepeat.Surfacevegetationintheprojectfootprintisassumedtoremainundisturbedbylineconstruction.ThisprofileisintendedtorepresentagenericgeotechnicalprofileinthelowerYukonandKuskokwimareas.
Profile“B”:Warmanddegradingpermafrost,primarilylow‐tomoderate‐plasticitymineralsiltwithelevatedporewatersalinity.Taliksorthinunbondedsoillayersmaybepresentinthefrozensoilmatrixwithin15to20feetbelowgrade.Temperaturesareexpectedtoaverage31.5to31.8°Fintheuppermost15feetbelowtheactivelayer.Degradingpermafrostconditionsareexpectedbelowtheactivelayerinsomeareasalongtheintertiealignment.Surfacevegetationintheprojectfootprintisassumedtoremainundisturbedbylineconstruction.ThisprofileisintendedtorepresentagenericgeotechnicalprofilealongcoastalareasofwesternAlaska.
Profile“C”:Thawedorunfrozenmineralsoil,generallysandywithsiltcontentsof20%to40%totaldryweight.Highlydegradedpermafrostwithsignificantthawedzonesispresentbelowtheactivelayer.Soilmoisturecontentsrepresentsaturatedconditionsandnosignificantporewatersalinityispresent.Ahigherorganiccontentactivelayerispresent,withgrasses,brush,andtreesforvegetation.Theactivelayerisapproximately5feet.ThisprofileisintendedtorepresentagenericgeotechnicalprofilealongthepermafrostmarginininteriorAlaskaorinlandareaswithsignificantpermafrostdegradation.
C.2.2 EnvironmentalLoads
Thefollowingloadingswereanalyzedforeachconceptualdesign:
Case1:NationalElectricalSafetyCode(NESC)250B=½inchofice,4poundspersquarefoot(psf)wind.
Case2:NESC250C=noice,120mphwind.
Page 117
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-9
Case3:NESC250D=¼inchofice,80mphwind.
Case4:Highice=1inchice,nowind,30degreesFahrenheit(°F).
Case5:Noiceorwind.
TheseloadcasesareconsideredsufficientformanyruralAlaskaoverheadintertieapplications.Specificlocationsmaybesubjecttohigherand/orlowerwindand/oriceloadings.30Exceptwherespecificallystatedotherwise,eachoftheconceptualdesignspresentedinthissectioncomplywiththemoststringentoftheseloadconditions.
30 Section4.6ofthePhaseIFinalReportprovidesasummaryofenvironmentalloadingsaroundAlaska(Polarconsult,2009)
Page 118
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-10
C.3 CONCEPTUALDESIGNOFOVERHEADHVDCTRANSMISSION,RUSSTANDARDPRACTICE
Theconceptualdesignsofoverheadintertielinespresentedinthissectionhavebeendevelopedtotakeadvantageofthefollowingfactors:
● Alaskacontractors,linecrews,andutilitylinepersonnelarefamiliarwithRUSstandardpracticematerials,designs,andconstructionpractices,thustheywillbemorefamiliarwiththetechniquesandproceduresforbuilding,maintaining,andrepairingtheselines.
● AlaskaalreadyhasmanymilesofRUSstandard‐practicedistributionandtransmissionlinesbuiltandinservicethroughoutthestate.Utilitiesunderstandtheperformancerecordandissueswiththistypeoflineconstruction.
● Utilitylenders,whichincludesRUS,understandandacceptRUSstandardconstructionpractice,whichcansimplifyobtainingfundsforconstructingnewinterties.
Totakeadvantageofthesefactors,conceptualdesignforHVDCpreservedRUSstandardpracticeconstructiontotheextentpossible,modifyingthepoletopassemblytoaccommodatetheconductor(s),insulator(s),andclearancesforHVDCoperation.TherulingspanisalsoincreasedtotakeadvantageofthefewerwiresandreducedstructureloadsassociatedwiththeHVDCcircuitconfigurations.
StructuralanalysisofconventionaloverheadHVDCtransmissionstructures(adaptedfromRUSstandardpractice)wasperformedbyPolarconsult.Aconceptualdesignsummaryispresentedinthefollowingsectionsforeachlineconfiguration.
C.3.1 ConventionalACIntertieDesign
ConventionalACintertiedesignsforlow‐power(under1MW)ruralAlaskaACintertielinesareconsideredinthisstudyforthefollowingreasons:
1. ThemajorityofexistingruralAlaskaintertiesarebuiltperRUSstandardpractice.Thus,thisconventionalACoverheadlineconfigurationisthebaselineforcomparisonsofcapitalcost,electricalefficiency,andothermetricsbywhichtheHVDCintertiesystemsareevaluatedinthisreport.
2. TheRUSstandardpracticeconstructionthatisusedformostACintertielinesinruralAlaskahasbeenusedinthisreportasthebasisforconceptualdesignofconventionallybuiltHVDCintertielines.
MostruralAlaskaACintertielinesaredesignedandconstructedperRUSstandardpractice,whichtypicallyusesdirect‐burialcantileveredwoodpoles.31Manyintertielines,suchasthoseintheYukon‐Kuskokwimregion,cannotusedirect‐burialcantileveredwoodpoledesignsduetotheadversegeotechnicalconditions.Intheseproblemareas,thewoodpoleiscommonlyattachedtoasteelpiledriventoadepthofasmuchas40feettoprovideanadequatefoundationforthecantileveredpole.Thewoodpolesaretypically35to45feetinlength,dependingonthesiteconditionsandlinedesign.
ThepolessupportastandardRUStangentpole‐topassemblyaspresentedonFigureC‐1.TheconceptualdesigndataforthistypeoflineconstructionisprovidedinTableC‐1.
31 SeeRUS,1998;RUS,2005.
Page 119
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-11
Figure C-1 Tangent Pole for Conventional AC Intertie Line
ImageCredit:RUS,1998
Page 120
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-12
Table C-1 Conceptual Design Data for Conventional AC Intertie Line
I. GENERAL INFORMATION
PROJECT: CONCEPTUAL 1 MW HVDC LINESUMMARY OF CONCEPTUAL DESIGN DATA LINE IDENTIFICATION: VOLTAGE:
RUS STD. AC CONSTRUCTION 14.4 / 24.9 KV AC
THREE‐PHASE 14.4 / 24.9 Kv AC INTERTIE TYPE
STANDARD RUS CONSTRUCTION THREE PHASE AC DIST LINE < 1 MW
TYPE OF TANGENT STRUCTURE: BASE POLE:
WOOD POLE 35 FT CLASS 1
DESIGNED BY: POLARCONSULT ALASKA (CONCEPT DESIGN)
II. CONDUCTOR DATA TRANSMISSION COMMON NEUTRAL
SIZE: 1/0 (raven) 1/0 (raven)
STRANDING: 6/1 6/1
MATERIAL: ACSR ACSR
DIAMETER (IN): 0.398 0.398
WEIGHT (LBS/FT): 0.145 0.145
RATED STRENGTH (LBS): 4,380 4,380
III. DESIGN LOADS
NESC LOADING DISTRICT: HEAVY TRANSMISSION (LBS/FT) COMMON NEUTRAL (LBS/FT)
a. ICE (IN.): (vertical) 0.5 in. radial 0.5 in. radial
b. WIND ON ICED COND (PSF): (transverse) 4.0 psf 4.0 psf
c. CONSTANT K: (resultant + K) 0.3 psf 0.3 psf
EXTREME ICE (NO WIND): (vertical) 1.0 in. radial 1.0 in. radial
EXTREME WIND (NO ICE): (transverse) 120 mph 30.6 psf 120 mph 30.6 psf
EXTREME ICE + WIND:
ICE: (vertical) 0.25 in. radial 0.25 in. radial
WIND: (transverse) 80 mph 13.6 psf 80 mph 13.6 psf
IV. SAG & TENSION DATA
RULING SPAN: 250 ft.
SOURCE OF SAG/TENSION DATA: SOUTHWIRE SAG10 TRANSMISSION COMMON NEUTRAL
TENSIONS (% RATED STRENGTH) INITIAL FINAL INITIAL FINAL
NESC a. UNLOADED TEMP: 60 F lbs: 1,333 642 1,333 642
30% 15% 30% 15%
NESC b. LOADED TEMP: 0 F lbs: 2,190 2,190
50% 50%
MAXIMUM ICE TEMP: 30 F lbs: 2,488 2,488
HIGH WIND (NO ICE) TEMP: 60 F lbs: 1,875 1,875
UNLOADED LOW TEMPERATUR TEMP: ‐20 F lbs: 1,868 1,868
SAGS (FT)
NESC DISTRICT LOADED TEMP: 0 F 3.61 3.61
UNLOADED HIGH TEMP TEMP: 212 F 3.56 3.56
MAXIMUM ICE TEMP: 30 F 5.93 5.93
LOADED 1/2" ICE, NO WIND TEMP: 32 F 3.73 3.73
V. CLEARANCES
MINIMUM CLEARANCES TO BE MAINTAINED AT: EXTREME ICE LOADING
CLEARANCES IN FEET RAILROADS ROADS CULTIVATED AREAS (REMOTE AREAS) ADD'L ALLOWANCE
TRANSMISSION CLR. TO GROUND NA 21.2 21.2 5.0
VI. RIGHT OF WAY
WIDTH: 30 FT. AT EXTREME WIND, FINAL SAG, AREAS WITH TYP. STRUCTURES ADJ. TO ROW
WIDTH: 35 FT. AT EXTREME WIND, FINAL SAG, CLEARANCE TO VEGETATION AT LINE ELEV.
Page 121
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-13
C.3.2 MonopolarSingle‐WireTransmissionwithEarth‐ReturnPath(SWER),ConventionallyBuilt
TheRUSstandardpracticeforanAClineconstruction(FigureC‐2)canbeadaptedforamonopolarSWERHVDCline.Thenecessarychangesarelistedbelow:
● Eliminationofthefour(orthree)conductors,insulators,andthecross‐armassembly.
● Additionofasingleconductorratedforthestructuralloadsandelectricalrequirementsoftheline.Aluminumconductorsteelreinforced(ACSR)4/0Penguinwasselectedfortheconceptualdesign.
● Addasinglelinepostinsulatorratedfornominal50kVDCandthestructuralloadsfromtheconductors.A115kVACNGKpolymerlinepostinsulator(#L4‐SN321‐15U)wasselectedfortheconceptualdesign.32
● Increasetherulingspanbetweenthepolesfrom250feet(typicalforAClines)to500feet.
Atangentpole‐topassemblyforaconventionallybuiltmonopolarHVDCSWERintertieisshownonFigureC‐2.TheconceptualdesigndataforthistypeoflineconstructionisprovidedinTableC‐2.
32 TheinsulatordesignisconsideredconservativeandisanticipatedtobeadequateformostregionsofAlaska.Insulatorsrated
atalowervoltagemaybeappropriateforsomeintertielines.
Page 122
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-14
Figure C-2 Conventional Tangent Pole for Monopolar SWER HVDC Intertie Line
Page 123
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-15
Table C-2 Conceptual Design Data for Conventionally Built Monopolar SWER HVDC Intertie Line
I. GENERAL INFORMATION
PROJECT: CONCEPTUAL 1 MW HVDC LINESUMMARY OF CONCEPTUAL DESIGN DATA LINE IDENTIFICATION: VOLTAGE:
RUS STD. AS HVDC SWER 50 KV HVDC
MONOPOLAR HVDC OVERHEAD INTERTIE, SWER CIRCUIT TYPE
STANDARD RUS CONSTRUCTION MONOPOLAR HVDC SWER
TYPE OF TANGENT STRUCTURE: BASE POLE:
WOOD POLE 35 FT CLASS 1
DESIGNED BY: POLARCONSULT ALASKA (CONCEPT DESIGN)
II. CONDUCTOR DATA TRANSMISSION COMMON NEUTRAL
SIZE: 4/0 'PENGUIN' (NONE)
STRANDING: 6/1
MATERIAL: ACSR
DIAMETER (IN): 0.563
WEIGHT (LBS/FT): 0.291
RATED STRENGTH (LBS): 8,350
III. DESIGN LOADS
NESC LOADING DISTRICT: HEAVY TRANSMISSION (LBS/FT) COMMON NEUTRAL (LBS/FT)
a. ICE (IN.): (vertical) 0.5 in. radial (NONE)
b. WIND ON ICED COND (PSF): (transverse) 4.0 psf
c. CONSTANT K: (resultant + K) 0.3 psf
EXTREME ICE (NO WIND): (vertical) 1.0 in. radial
EXTREME WIND (NO ICE): (transverse) 120 mph 31.1 psf
EXTREME ICE + WIND:
ICE: (vertical) 0.25 in. radial
WIND: (transverse) 80 mph 13.8 psf
IV. SAG & TENSION DATA
RULING SPAN: 500 ft.
SOURCE OF SAG/TENSION DATA: SOUTHWIRE SAG10 TRANSMISSION COMMON NEUTRAL
TENSIONS (% RATED STRENGTH) INITIAL FINAL INITIAL FINAL
NESC a. UNLOADED TEMP: 60 F lbs: 1,999 1,142 (NONE)
24% 14%
NESC b. LOADED TEMP: 0 F lbs: 4,175
50%
MAXIMUM ICE TEMP: 30 F lbs: 4,982
HIGH WIND (NO ICE) TEMP: 60 F lbs: 3,915
UNLOADED LOW TEMPERATUR TEMP: ‐20 F lbs: 3,013
SAGS (FT)
NESC DISTRICT LOADED TEMP: 0 F 9.71
UNLOADED HIGH TEMP TEMP: 212 F 11.32
MAXIMUM ICE TEMP: 30 F 14.06
LOADED 1/2" ICE, NO WIND TEMP: 32 F 10.44
V. CLEARANCES
MINIMUM CLEARANCES TO BE MAINTAINED AT: EXTREME ICE LOADING
CLEARANCES IN FEET RAILROADS ROADS CULTIVATED AREAS (REMOTE AREAS) ADD'L ALLOWANCE
TRANSMISSION CLR. TO GROUND NA 21.7 21.7 5.0
VI. RIGHT OF WAY
WIDTH: 40 FT. AT EXTREME WIND, FINAL SAG, AREAS WITH TYP. STRUCTURES ADJ. TO ROW
WIDTH: 45 FT. AT EXTREME WIND, FINAL SAG, CLEARANCE TO VEGETATION AT LINE ELEV.
Page 124
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-16
C.3.3 MonopolarTwo‐WireTransmissionwithMetallicConductor‐ReturnPath(TWMR),ConventionallyBuilt
ThestandardRUSdesignforanAClinecanbeadaptedforamonopolarHVDClinewithmetallicreturn.Necessaryadaptationsarelistedbelow:
● Eliminatethefour(orthree)conductors,insulators,andthecross‐armassembly.
● Increasetherulingspanfortheintertielinefromatypical250feetupto500feet.
● Addonecantileveredlinepostinsulatorratedfornominal50kVDCandthestructuralloadsfromtheconductors.115kVACNGKpolymerlinepostinsulators(#L4‐SN321‐23)wereselectedfortheconceptualdesign.
● Addoneoffsetneutralbracketforthemetallicreturnconductor.
● Addtwoconductorsratedforthestructuralloadsandelectricalrequirementsoftheline.ACSR4/0Penguinwasselectedfortheconceptualdesignforbothhigh‐voltageconductors.
Atangentpole‐topassemblyforthisconceptualdesignisshownonFigureC‐3.TheconceptualdesigndataforthistypeoflineconstructionisprovidedinTableC‐3.
Page 125
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-17
Figure C-3 Conventional Tangent Pole for Monopolar HVDC with Metallic Return
Page 126
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-18
Table C-3 Conceptual Design Data for Conventionally Built Monopolar HVDC with Metallic Return
I. GENERAL INFORMATION
PROJECT: CONCEPTUAL 1 MW HVDC LINESUMMARY OF CONCEPTUAL DESIGN DATA LINE IDENTIFICATION: VOLTAGE:
RUS STD. AS HVDC TWMR 50 KV HVDC
MONOPOLAR HVDC INTERTIE ‐ TWMR CIRCUIT TYPE
(METALLIC RETURN) MONOPOLAR HVDC ‐ METALLIC RETURN
STANDARD RUS CONSTRUCTION TYPE OF TANGENT STRUCTURE: BASE POLE:
WOOD POLE 45 FT CLASS 1
DESIGNED BY: POLARCONSULT ALASKA (CONCEPT DESIGN)
II. CONDUCTOR DATA TRANSMISSION COMMON NEUTRAL
SIZE: 4/0 'PENGUIN' 4/0 'PENGUIN'
STRANDING: 6/1 6/1
MATERIAL: ACSR ACSR
DIAMETER (IN): 0.563 0.563
WEIGHT (LBS/FT): 0.291 0.291
RATED STRENGTH (LBS): 8,350 8,350
III. DESIGN LOADS
NESC LOADING DISTRICT: HEAVY TRANSMISSION (LBS/FT) COMMON NEUTRAL (LBS/FT)
a. ICE (IN.): (vertical) 0.5 in. radial 0.5 in. radial
b. WIND ON ICED COND (PSF): (transverse) 4.0 psf 4.0 psf
c. CONSTANT K: (resultant + K) 0.3 psf 0.3 psf
EXTREME ICE (NO WIND): (vertical) 1.0 in. radial 1.0 in. radial
EXTREME WIND (NO ICE): (transverse) 120 mph 32.2 psf 120 mph 32.2 psf
EXTREME ICE + WIND:
ICE: (vertical) 0.25 in. radial 0.25 in. radial
WIND: (transverse) 80 mph 14.3 psf 80 mph 14.3 psf
IV. SAG & TENSION DATA
RULING SPAN: 500 ft.
SOURCE OF SAG/TENSION DATA: SOUTHWIRE SAG10 TRANSMISSION COMMON NEUTRAL
TENSIONS (% RATED STRENGTH) INITIAL FINAL INITIAL FINAL
NESC a. UNLOADED TEMP: 60 F lbs: 1,999 1,142 1,999 1,142
24% 14% 24% 14%
NESC b. LOADED TEMP: 0 F lbs: 4,175 4,175
50% 50%
MAXIMUM ICE TEMP: 30 F lbs: 4,982 4,982
HIGH WIND (NO ICE) TEMP: 60 F lbs: 3,983 3,983
UNLOADED LOW TEMPERATUR TEMP: ‐20 F lbs: 3,013 3,013
SAGS (FT)
NESC DISTRICT LOADED TEMP: 0 F 9.71 9.71
UNLOADED HIGH TEMP TEMP: 212 F 11.32 11.32
MAXIMUM ICE TEMP: 30 F 14.06 14.06
LOADED 1/2" ICE, NO WIND TEMP: 32 F 10.44 10.44
V. CLEARANCES
MINIMUM CLEARANCES TO BE MAINTAINED AT: EXTREME ICE LOADING
CLEARANCES IN FEET RAILROADS ROADS CULTIVATED AREAS (REMOTE AREAS) ADD'L ALLOWANCE
TRANSMISSION CLR. TO GROUND NA 21.7 21.7 5.0
VI. RIGHT OF WAY
WIDTH: 50 FT. AT EXTREME WIND, FINAL SAG, AREAS WITH TYP. STRUCTURES ADJ. TO ROW
WIDTH: 45 FT. AT EXTREME WIND, FINAL SAG, CLEARANCE TO VEGETATION AT LINE ELEV.
Page 127
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-19
C.3.4 BipolarTwo‐WireTransmission,ConventionallyBuilt
ThestandardRUSdesignforanAClinecanbeadaptedforabipolarHVDCline.Necessaryadaptationsarelistedbelow:
● Eliminatethefour(orthree)conductors,insulators,andthecross‐armassembly.
● Increasetherulingspanfortheintertielinefromatypical250feetupto500feet.
● Addtwocantileveredpostinsulatorsratedfornominal50kVDCandthestructuralloadsfromtheconductors.A115kVACNGKpolymerlinepostinsulator(#L4‐SN321‐15U)wasselectedfortheconceptualdesign.
● Addtwoconductorsratedforthestructuralloadsandelectricalrequirementsoftheline.ACSR4/0Penguinwasselectedfortheconceptualdesignforboththehigh‐voltageandmetallic‐returnconductors.
Atangentpole‐topassemblyforthisconceptualdesignisshownonFigureC‐4.TheconceptualdesigndataforthistypeoflineconstructionisprovidedinTableC‐4.
Page 128
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-20
Figure C-4 Conventional Tangent Pole for Bipolar HVDC Intertie Line
Page 129
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-21
Table C-4 Conceptual Design Data for Conventionally Built Bipolar HVDC Intertie Line
I. GENERAL INFORMATION
PROJECT: CONCEPTUAL 2 MW HVDC LINESUMMARY OF CONCEPTUAL DESIGN DATA LINE IDENTIFICATION: VOLTAGE:
RUS STD. AS BIPOLAR HVDC +/‐ 50 KV HVDC
BIPOLAR HVDC INTERTIE TYPE
STANDARD RUS CONSTRUCTION BIPOLAR HVDC
TYPE OF TANGENT STRUCTURE: BASE POLE:
WOOD POLE 40 FT CLASS 1
DESIGNED BY: POLARCONSULT ALASKA (CONCEPT DESIGN)
II. CONDUCTOR DATA TRANSMISSION + 50 kVDC TRANSMISSION ‐ 50 kVDC
SIZE: 4/0 'PENGUIN' 4/0 'PENGUIN'
STRANDING: 6/1 6/1
MATERIAL: ACSR ACSR
DIAMETER (IN): 0.563 0.563
WEIGHT (LBS/FT): 0.291 0.291
RATED STRENGTH (LBS): 8,350 8,350
III. DESIGN LOADS
NESC LOADING DISTRICT: HEAVY TRANSMISSION (LBS/FT) TRANSMISSION (LBS/FT)
a. ICE (IN.): (vertical) 0.5 in. radial 0.5 in. radial
b. WIND ON ICED COND (PSF): (transverse) 4.0 psf 4.0 psf
c. CONSTANT K: (resultant + K) 0.3 psf 0.3 psf
EXTREME ICE (NO WIND): (vertical) 1.0 in. radial 1.0 in. radial
EXTREME WIND (NO ICE): (transverse) 120 mph 31.2 psf 120 mph 31.2 psf
EXTREME ICE + WIND:
ICE: (vertical) 0.25 in. radial 0.25 in. radial
WIND: (transverse) 80 mph 13.9 psf 80 mph 13.9 psf
IV. SAG & TENSION DATA
RULING SPAN: 500 ft.
SOURCE OF SAG/TENSION DATA: SOUTHWIRE SAG10 TRANSMISSION TRANSMISSION
TENSIONS (% RATED STRENGTH) INITIAL FINAL INITIAL FINAL
NESC a. UNLOADED TEMP: 60 F lbs: 1,999 1,142 1,999 1,142
24% 14% 24% 14%
NESC b. LOADED TEMP: 0 F lbs: 4,175 4,175
50% 50%
MAXIMUM ICE TEMP: 30 F lbs: 4,982 4,982
HIGH WIND (NO ICE) TEMP: 60 F lbs: 3,922 3,922
UNLOADED LOW TEMPERATUR TEMP: ‐20 F lbs: 3,013 3,013
SAGS (FT)
NESC DISTRICT LOADED TEMP: 0 F 9.71 9.71
UNLOADED HIGH TEMP TEMP: 212 F 11.32 11.32
MAXIMUM ICE TEMP: 30 F 14.06 14.06
LOADED 1/2" ICE, NO WIND TEMP: 32 F 10.44 10.44
V. CLEARANCES
MINIMUM CLEARANCES TO BE MAINTAINED AT: EXTREME ICE LOADING
CLEARANCES IN FEET RAILROADS ROADS CULTIVATED AREAS (REMOTE AREAS) ADD'L ALLOWANCE
TRANSMISSION CLR. TO GROUND NA 21.7 21.7 5.0
VI. RIGHT OF WAY
WIDTH: 50 FT. AT EXTREME WIND, FINAL SAG, AREAS WITH TYP. STRUCTURES ADJ. TO ROW
WIDTH: 45 FT. AT EXTREME WIND, FINAL SAG, CLEARANCE TO VEGETATION AT LINE ELEV.
Page 130
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-22
C.4 CONCEPTUALDESIGNOFOVERHEADHVDCTRANSMISSION,ALASKA‐SPECIFICMETHODS
TheconceptualdesignsofoverheadintertielinespresentedinthissectionhavebeendevelopedtoreduceconstructioncostsonruralAlaskainterties.Costreductionisachievedthroughspecialattentiontothefactorslistedbelow.
● Minimizingtherelianceonheavyequipmentthatmustbemobilizedtoaconstructionsite.Iflighterequipmentorlocalequipmentcanbeusedforconstruction,mobilizationcostswillbeless,reducingprojectcosts.
● Maximizingtheflexibilityinconstructionmethodsandseasons.Bydesigningfortheuseofsmallerequipment,greateruseofhelicoptersforconstructionsupport,andsimilartechniques,all‐seasonconstructionbecomespossible,creatingnewopportunitiestoincreaseutilizationofequipment,increasecompetitionforlineconstructionprojects,andreduceprojectcosts.
Thesefactorshavebeenincorporatedintotheconceptualdesignelementslistedbelow.
● Useoftallerstructuresandlongerspans.BecauseHVDCcircuitsrequireonlyoneortwowires,theycanutilizelongerspansthanacomparablethree‐orfour‐wireACcircuit.Increasingspansreducesthenumberofstructuresandfoundationsforagivenlengthofoverheadline,whichreducescosts.Withthisapproach,tallerstructuresareneededtomaintainrequiredclearancesbetweentheconductorandtheground.
● Useofglass‐fiber‐reinforcedpolymer(GFRP)polesinsteadofwoodorsteelpoles.GFRPpoleshavebeenusedforover50yearsinelectricutilityapplications33buthavelittletonohistoryinAlaska’selectricutilityindustry.GFRPpolesarelighterthanwoodorsteelpolessotheycanbetransportedbyasmallhelicoptersuchasaHughes500orBellUH‐1“Huey.”Theyarealsorot‐resistantanddonotleachtoxicpreservativesintothesoilsaroundthepole.ThePhaseIIprojectincludeddemonstrationofafield‐friendlyspliceforGFRPpoles,whichpermitstallpolestobeshippedinpartsandassembledinthefield.ThissplicecanalsobeusedforfieldrepairofdamagedGFRPpoles.
● Useofguyedstructuresinareaswheregeotechnicalconditionspreventcantileveredpolesfrombeingdirectlyburiedinthesoil.Acceptedpracticeforsuchconditionsistodriveasteelpileupto40feetdeepandthenfastenawoodpoletothesteelpile.Installingthesteelpilerequiresmobilizingacraneorotherheavyequipmenttotheprojectsite.Aguyedstructurecanbeinstalledinsuchconditionswithamuchsmallerbasefoundation,astheguyscarrymostofthemoment,andthestructurebasemostlycarriescompressiveloads.
ThefollowingsectionsdescribeconceptualdesignsusingtheseAlaska‐specificmethodsforthefollowingtypesofHVDCcircuits:
● MonopolarSWER;
● MonopolarTWMR;
● Bipolartwo‐wiretransmission.
Inallcases,theconceptualdesignspresentedinthefollowingsectionscomplywiththedesigncriteria,loadfactors,andstrengthfactorssetforthinSectionC.2ofthisappendixandbyRUS.34
33Ibrahim,2000.34 RUS,2009
Page 131
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-23
C.4.1 MonopolarSingle‐WireTransmissionwithEarth‐ReturnPath(SWER,Alaska‐SpecificDesign
TheAlaska‐specificconceptualdesignforamonopolarHVDClineconsistsofthefollowingelements:
● Single19#10Alumoweldconductorinstalledatarulingspanof1,000feet.
● Asinglelinepostinsulatorratedfornominal50kVDCandthestructuralloadsfromtheconductors.A115kVACNGKpolymerlinepostinsulator(#L4‐SN321‐15U)wasselectedfortheconceptualdesign.35
● A14‐inch‐diameter,0.375‐inchwall,50‐foot‐tallGFRPpole.Thispolecanbeincreasedto70feetifneededwithoutmodificationforspansupto1,500feetorforincreasedgroundorterrainclearances.
● Fourguysattachedtothepoletopinstalledata45‐degreeangletotheconductoranda45‐degreeangletoground.
● Guyanchorsconsistingoftwoflightsof8‐inchscrewanchorsdriven10to15feetintotheground.
● Apolebasefoundationconsistingofthree1½‐inchby25‐footthermoprobemicropilesinstalledtoadepthof20feet.Theremaining5feetserveasthethermoproberadiator.
Atangentpole‐topassemblyforthismonopolarHVDCSWERintertieconceptualdesignisshownonFigureC‐5.TheconceptualdesigndataforthistypeoflineconstructionisprovidedinTableC‐5.
35 TheinsulatordesignisconsideredconservativeandisanticipatedtobeadequateformostregionsofAlaska.Insulatorsrated
atalowervoltagemaybeappropriateforsomeintertielines.
Page 132
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-24
Figure C-5 Alaska-Specific Tangent Pole for Monopolar SWER HVDC Intertie Line
Page 133
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-25
Table C-5 Conceptual Design Data for Alaska-Specific Monopolar SWER HVDC Intertie Line
I. GENERAL INFORMATION
PROJECT: CONCEPTUAL 1 MW HVDC LINESUMMARY OF CONCEPTUAL DESIGN DATA LINE IDENTIFICATION: VOLTAGE:
AK SPECIFIC HVDC SWER DES. 50 KV HVDC
MONOPOLAR HVDC OVERHEAD INTERTIE, SWER CIRCUIT TYPE
ALASKA‐SPECIFIC CONSTRUCTION MONOPOLAR HVDC SWER
TYPE OF TANGENT STRUCTURE: BASE POLE:
GUYED FRP POLE 45 FT FRP POLE
DESIGNED BY: POLARCONSULT ALASKA (CONCEPT DESIGN)
II. CONDUCTOR DATA TRANSMISSION COMMON NEUTRAL
SIZE: 19#10 ALUMOWELD (NONE)
STRANDING: 19#10
MATERIAL: ALUMOWELD
DIAMETER (IN): 0.509
WEIGHT (LBS/FT): 0.449
RATED STRENGTH (LBS): 27,190
III. DESIGN LOADS
NESC LOADING DISTRICT: HEAVY TRANSMISSION (LBS/FT) COMMON NEUTRAL (LBS/FT)
a. ICE (IN.): (vertical) 0.5 in. radial (NONE)
b. WIND ON ICED COND (PSF): (transverse) 4.0 psf
c. CONSTANT K: (resultant + K) 0.3 psf
EXTREME ICE (NO WIND): (vertical) 1.0 in. radial
EXTREME WIND (NO ICE): (transverse) 120 mph 32.2 psf
EXTREME ICE + WIND:
ICE: (vertical) 0.25 in. radial
WIND: (transverse) 80 mph 14.3 psf
IV. SAG & TENSION DATA
RULING SPAN: 1,000 ft.
SOURCE OF SAG/TENSION DATA: SOUTHWIRE SAG10 TRANSMISSION COMMON NEUTRAL
TENSIONS (% RATED STRENGTH) INITIAL FINAL INITIAL FINAL
NESC a. UNLOADED TEMP: 60 F lbs: 8,071 6,798 (NONE)
30% 25%
NESC b. LOADED TEMP: 0 F lbs: 11,246
41%
MAXIMUM ICE TEMP: 30 F lbs: 12,637
HIGH WIND (NO ICE) TEMP: 60 F lbs: 10,075
UNLOADED LOW TEMPERATUR TEMP: ‐20 F lbs: 9,736
SAGS (FT)
NESC DISTRICT LOADED TEMP: 0 F 15.97
UNLOADED HIGH TEMP TEMP: 212 F 13.73
MAXIMUM ICE TEMP: 30 F 23.85
LOADED 1/2" ICE, NO WIND TEMP: 32 F 15.02
V. CLEARANCES
MINIMUM CLEARANCES TO BE MAINTAINED AT: EXTREME ICE LOADING
CLEARANCES IN FEET RAILROADS ROADS CULTIVATED AREAS (REMOTE AREAS) ADD'L ALLOWANCE
TRANSMISSION CLR. TO GROUND NA 21.7 21.7 5.0
VI. RIGHT OF WAY
WIDTH: 60 FT. AT EXTREME WIND, FINAL SAG, AREAS WITH TYP. STRUCTURES ADJ. TO ROW
WIDTH: 70 FT. FOOTPRINT OF 4‐GUYED STRUCTURE, GUYS AT 45 DEGREES TO LINE
WIDTH: 95 FT. FOOTPRINT OF 4‐GUYED STRUCTURE, GUYS IN LINE AND NORMAL TO CONDUCTOR.
WIDTH: 55 FT. AT EXTREME WIND, FINAL SAG, CLEARANCE TO VEGETATION AT LINE ELEV.
Page 134
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-26
C.4.2 MonopolarTwo‐WireTransmissionwithMetallicConductor‐ReturnPath(TWMR),Alaska‐SpecificDesign
TheAlaska‐specificconceptualdesignforamonopolarHVDCline(FigureC‐6)canbeadaptedforatwo‐wiremonopolarHVDClinewithmetallicreturn.Thenecessarychangesarelistedbelow:
● IncreasetheGFRPpoleheightfrom50feetto65feet.NochangeisneededinthepolesectionormaterialundertheloadcaseslistedinSectionC.2.
● Additionofasecond19#10Alumoweldconductorsupportedbyanoffsetbracket15feetbelowthetopofthepole.Atthisattachmentpoint,thissecondconductorwillhaveadequateclearancefromtheguys,ground,andthehigh‐voltageconductorunderallloadconditionslistedinSectionC.2ofthisappendix.
● Maintaintherulingspanat1,000feet.
Atangentpole‐topassemblyforaconventionallybuilttwo‐wiremonopolarHVDCintertieisshownonFigureC‐6.TheconceptualdesigndataforthistypeoflineconstructionisprovidedinTableC‐6.
Page 135
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-27
Figure C-6 Alaska-Specific Tangent Pole for Monopolar Metallic-Return Intertie Line
Page 136
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-28
Table C-6 Conceptual Design Data for Alaska-Specific Monopolar Metallic-Return Intertie Line
I. GENERAL INFORMATION
PROJECT: CONCEPTUAL 1 MW HVDC LINESUMMARY OF CONCEPTUAL DESIGN DATA LINE IDENTIFICATION: VOLTAGE:
AK SPECIFIC HVDC SWER DES. 50 KV HVDC
MONOPOLAR HVDC OVERHEAD INTERTIE TMWR CIRCUIT TYPE
(METALLIC RETURN) MONOPOLAR HVDC WITH METALLIC RETURN
ALASKA‐SPECIFIC CONSTRUCTION TYPE OF TANGENT STRUCTURE: BASE POLE:
GUYED FRP POLE 65 FT FRP POLE
DESIGNED BY: POLARCONSULT ALASKA (CONCEPT DESIGN)
II. CONDUCTOR DATA TRANSMISSION COMMON NEUTRAL
SIZE: 19#10 ALUMOWELD 19#10 ALUMOWELD
STRANDING: 19#10 19#10
MATERIAL: ALUMOWELD ALUMOWELD
DIAMETER (IN): 0.509 0.509
WEIGHT (LBS/FT): 0.449 0.449
RATED STRENGTH (LBS): 27,190 27,190
III. DESIGN LOADS
NESC LOADING DISTRICT: HEAVY TRANSMISSION (LBS/FT) COMMON NEUTRAL (LBS/FT)
a. ICE (IN.): (vertical) 0.5 in. radial 0.5 in. radial
b. WIND ON ICED COND (PSF): (transverse) 4.0 psf 4.0 psf
c. CONSTANT K: (resultant + K) 0.3 psf 0.3 psf
EXTREME ICE (NO WIND): (vertical) 1.0 in. radial 1.0 in. radial
EXTREME WIND (NO ICE): (transverse) 120 mph 34.0 psf 120 mph 34.0 psf
EXTREME ICE + WIND:
ICE: (vertical) 0.25 in. radial 0.3 in. radial
WIND: (transverse) 80 mph 15.1 psf 80 mph 15.1 psf
IV. SAG & TENSION DATA
RULING SPAN: 1,000 ft.
SOURCE OF SAG/TENSION DATA: SOUTHWIRE SAG10 TRANSMISSION COMMON NEUTRAL
TENSIONS (% RATED STRENGTH) INITIAL FINAL INITIAL FINAL
NESC a. UNLOADED TEMP: 60 F lbs: 8,071 6,798 8,071 6,798
30% 25% 30% 25%
NESC b. LOADED TEMP: 0 F lbs: 11,246 11,246
41% 41%
MAXIMUM ICE TEMP: 30 F lbs: 12,637 12,637
HIGH WIND (NO ICE) TEMP: 60 F lbs: 10,075 10,075
UNLOADED LOW TEMPERATUR TEMP: ‐20 F lbs: 9,736 9,736
SAGS (FT)
NESC DISTRICT LOADED TEMP: 0 F 15.97 15.97
UNLOADED HIGH TEMP TEMP: 212 F 13.73 13.73
MAXIMUM ICE TEMP: 30 F 23.85 23.85
LOADED 1/2" ICE, NO WIND TEMP: 32 F 15.02 15.02
V. CLEARANCES
MINIMUM CLEARANCES TO BE MAINTAINED AT: EXTREME ICE LOADING
CLEARANCES IN FEET RAILROADS ROADS CULTIVATED AREAS (REMOTE AREAS) ADD'L ALLOWANCE
TRANSMISSION CLR. TO GROUND NA 21.7 21.7 5.0
VI. RIGHT OF WAY
WIDTH: 60 FT. FOR EXTREME WIND, FINAL SAG, AREAS WITH TYP. STRUCTURES ADJ. TO ROW
WIDTH: 100 FT. FOOTPRINT OF 4‐GUYED STRUCTURE, GUYS AT 45 DEGREES TO LINE
WIDTH: 135 FT. FOOTPRINT OF 4‐GUYED STRUCTURE, GUYS IN LINE AND NORMAL TO CONDUCTOR.
WIDTH: 60 FT. FOR EXTREME WIND, FINAL SAG, CLEARANCE TO VEGETATION AT LINE ELEV.
Page 137
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-29
C.4.3 BipolarHVDCIntertieLine,AlaskaSpecificDesign
TheAlaska‐specificconceptualdesignforamonopolarHVDCline(FigureC‐7)canbeadaptedforatwo‐wirebipolarHVDCline.Thenecessarychangesarelistedbelow:
● IncreasetheGFRPpoleheightfrom50feetto55feet.Nochangeisneededinthepolesectionormaterial.
● Eliminatethepost‐topinsulatorandaddtwo8‐foot‐longcross‐arms.APowertrusion#SH2096100Norequalwasselectedfortheconceptualdesign.
● Installtwosuspensioninsulatorsoffeachendofthecross‐arm.A115‐kVACNGKsuspensioninsulator#251‐SE510‐EEorequalwasselectedfortheconceptualdesign.
● Use19#10Alumoweldastheconductorforboththepositiveandnegativepolesofthecircuit.
● Maintainthesamespanlengthof1,000feet.
Atangentpole‐topassemblyforanAlaska‐specificbipolartwo‐wireHVDCintertieisshownonFigureC‐7.TheconceptualdesigndataforthistypeoflineconstructionisprovidedinTableC‐7.
Page 138
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-30
Figure C-7 Alaska-Specific Tangent Pole for Bipolar HVDC Intertie Line
Page 139
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-31
Table C-7 Conceptual Design Data for Alaska-Specific Bipolar HVDC Intertie Line
I. GENERAL INFORMATION
PROJECT: CONCEPTUAL 1 MW HVDC LINESUMMARY OF CONCEPTUAL DESIGN DATA LINE IDENTIFICATION: VOLTAGE:
AK SPECIFIC HVDC SWER DES. 50 KV HVDC
BIPOLAR HVDC INTERTIE TYPE
ALASKA‐SPECIFIC CONSTRUCTION BIPOLAR HVDC
TYPE OF TANGENT STRUCTURE: BASE POLE:
GUYED FRP POLE 55 FT FRP POLE
DESIGNED BY: POLARCONSULT ALASKA (CONCEPT DESIGN)
II. CONDUCTOR DATA TRANSMISSION COMMON NEUTRAL
SIZE: 19#10 ALUMOWELD 19#10 ALUMOWELD
STRANDING: 19#10 19#10
MATERIAL: ALUMOWELD ALUMOWELD
DIAMETER (IN): 0.509 0.509
WEIGHT (LBS/FT): 0.449 0.449
RATED STRENGTH (LBS): 27,190 27,190
III. DESIGN LOADS
NESC LOADING DISTRICT: HEAVY TRANSMISSION (LBS/FT) COMMON NEUTRAL (LBS/FT)
a. ICE (IN.): (vertical) 0.5 in. radial 0.5 in. radial
b. WIND ON ICED COND (PSF): (transverse) 4.0 psf 4.0 psf
c. CONSTANT K: (resultant + K) 0.3 psf 0.3 psf
EXTREME ICE (NO WIND): (vertical) 1.0 in. radial 1.0 in. radial
EXTREME WIND (NO ICE): (transverse) 120 mph 32.3 psf 120 mph 32.3 psf
EXTREME ICE + WIND:
ICE: (vertical) 0.25 in. radial 0.3 in. radial
WIND: (transverse) 80 mph 14.3 psf 80 mph 14.3 psf
IV. SAG & TENSION DATA
RULING SPAN: 1,000 ft.
SOURCE OF SAG/TENSION DATA: SOUTHWIRE SAG10 TRANSMISSION COMMON NEUTRAL
TENSIONS (% RATED STRENGTH) INITIAL FINAL INITIAL FINAL
NESC a. UNLOADED TEMP: 60 F lbs: 8,071 6,798 8,071 6,798
30% 25% 30% 25%
NESC b. LOADED TEMP: 0 F lbs: 11,246 11,246
41% 41%
MAXIMUM ICE TEMP: 30 F lbs: 12,637 12,637
HIGH WIND (NO ICE) TEMP: 60 F lbs: 10,075 10,075
UNLOADED LOW TEMPERATUR TEMP: ‐20 F lbs: 9,736 9,736
SAGS (FT)
NESC DISTRICT LOADED TEMP: 0 F 15.97 15.97
UNLOADED HIGH TEMP TEMP: 212 F 13.73 13.73
MAXIMUM ICE TEMP: 30 F 23.85 23.85
LOADED 1/2" ICE, NO WIND TEMP: 32 F 15.02 15.02
V. CLEARANCES
MINIMUM CLEARANCES TO BE MAINTAINED AT: EXTREME ICE LOADING
CLEARANCES IN FEET RAILROADS ROADS CULTIVATED AREAS (REMOTE AREAS) ADD'L ALLOWANCE
TRANSMISSION CLR. TO GROUND NA 21.7 21.7 5.0
VI. RIGHT OF WAY
WIDTH: 60 FT. FOR EXTREME WIND, FINAL SAG, AREAS WITH TYP. STRUCTURES ADJ. TO ROW
WIDTH: 95 FT. FOOTPRINT OF 4‐GUYED STRUCTURE, GUYS AT 45 DEGREES TO LINE
WIDTH: 125 FT. FOOTPRINT OF 4‐GUYED STRUCTURE, GUYS IN LINE AND NORMAL TO CONDUCTOR.
WIDTH: 55 FT. FOR EXTREME WIND, FINAL SAG, CLEARANCE TO VEGETATION AT LINE ELEV.
Page 140
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-32
C.4.4 ConceptualDesignAnalysis
Theconceptualdesignofoverheadtransmissionstructuresandfoundationsconsideredmethodsforconstruction,long‐termoperation,maintenance,repair,andreplacementoftheHVDCtransmissioninfrastructure.
C.4.4.1 ConstructionMethods
Thecost‐reductionpotentialofHVDConruralAlaskaprojectsmayberealizedusingoptimizedconstructionmethods.
Theuseoflightweightoverheadstructuresandfoundationsallowssignificantlatitudefortheconstructionandmaintenanceofthelines.Theuseofhelicopterstostagethematerialsandconstructionequipmentbecomespossible.
ConventionalACtransmissionlineconstructionistypicallyperformedinthewintertosupporttheheavyequipmentrequiredforconstruction.Thisequipmentoftenincludeslargepile‐drivingordrillingmachinesthatcanonlybeoperatedonfrozenground.Theresultingwinterconstructionschedule,combinedwithsummermobilizationoftheequipment,contributessignificantlytothehighcostofACinterties.
ACtransmissionstructuresandfoundationsareusuallybasedonacantileverpoledesign.Forthelow‐strengthgeotechnicalconditionsfoundinmuchofruralAlaska,thisdesignapproachisinefficientcomparedtotheuseofaxiallyloadedguyedstructuresproposedintheHVDCconceptualdesign.
TheHVDCconstructionapproachcanutilizeHughes500orBellUH‐1typehelicopters,whicharecommonlyavailableinAlaska.Thesehelicoptershaveaslingcapacityofapproximately1,000and3,000pounds,respectively.TheHVDCcompositepolestructures,guywires,screwfoundations,thermoprobefoundations,andothertransmissioncomponentscanbereadilystagedbythesehelicopters.Installationequipmentandotherconstructiontoolsareavailableinsizesthatcanbeliftedbyhelicopter.
Inaddition,thisconstructionapproachinvolvestheuseoftracked,low‐ground‐pressurevehicleswithattachmentsoptimizedfortheinstallationoftheHVDCfoundationsanderectionofthecompositepolestructures.TheidealvehiclewouldbesimilartoahydraulicallydrivenBBCarrier.TheBBCarrierwasapredecessorofNodwelltrackedvehicles,butmuchsmaller36.Thehydraulicdrivesystemcanbeusedtopowerdrills,winches,spades,impactdrivers,andotheronboardequipmentusedforlineconstruction37.
C.4.4.2 RecommendedConstructionApproach
ThefollowingnarrativesetsforththegeneralconstructionapproachrecommendedfortheconceptualoverheadHVDCintertiedesignpresentedherein.Preferredconstructionmethodsforanyspecificintertiewilldifferfromthisapproachandwillaffectconstructioncosts.
1. Identifyandprocurepropertyrightstotheintertiealignment.Standardpracticesforthiseffortareappropriateandarenotduplicatedhere.
36 TheBBCarrierwasmanufacturedinthelate1950sandearly1960sbyBombardier.Itisnolongerinproductionandisquite
raretoday.Itfeaturedagrossvehicleweightofabout2,000pounds,apayloadcapacityofabout1,000pounds,andagroundpressureoflessthanonepsi.Itsdrivetrainusedaplanetarytransmission,maintainingpowertobothtracksduringturns,whichreducedthetendencyofthesevehiclestodamagefragiletundravegetation.
37 A20,000to30,000‐ft‐lbhydraulicimpactdriverheadonasmallboomwouldbeusefulfordrivingfoundationscrewanchors.
Page 141
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-33
2. Sendanengineeringcrewandsurveypartytosurveythelineanddeterminepolelocationsinthefield.Surveyingandpreliminarylinedesignmaybecompletedbeforehandbyremotemethods(e.g.,lightdetectionandranging[LIDAR]survey).Theengineeringcrewwillconductgeotechnicaltestingateachpolesitetodeterminethetypeoffoundationrequired.Asappropriate,theengineeringcrewmayadjustpolelocationsbasedonencounteredconditions.
3. Orderandshipmaterialstotheprojectsite.Dependingontheproject,oneorbothvillageswillbeusedasthebaseofoperations.Itmaybecost‐effectivetopreassemblepoleorfoundationunitspriortoshippingtothesite.
4. Prepareandinstallpolefoundations.Dependingontheproject,polefoundationsmaybeshippedreadytoinstallormayrequiresomeassemblyinthevillage.Oncereadytodeploytothefield,thefoundationsforeachpole(polebaseandthreeguyfoundations)willbeairliftedtothepolesitebyhelicopter.Asmalllow‐ground‐pressurevehiclewillbeusedtoinstallthefoundations.Dependingontheterrain,thisstagemayoccurduringthelatewinterorsummermonths.Thegroundvehiclewillremaininthefield,andpersonnelandconsumableswillbetransportedtothevehicledailybyair.Thiswillreducetransittimes.
5. Prepareandassemblepoles.Thiswilloccurinoneorbothvillagesandmayincludesplicingthepoles,attachingthepoletopandbasehardware,attachingthepostinsulatorandstringingblocks,andattachingtheguywiresandhardware.Anassembledpolewillbepackagedinamannersuitableforairliftandclearlylabeledsoitisdeployedtotheproperfoundation.
6. Poleinstallation.Eachassembledpolewillbeairliftedbyhelicoptertothepole'sfoundation.Thepolewillbespottedonthegroundbythehelicopterandagroundcrew.ThegroundcrewwilluseanA‐frameandtheirsmall,low‐ground‐pressurevehicletoerectthepoleusingtwooftheguyanchorsashoistpoints.Alternatively,thehelicoptercouldbeusedforfastererectingandsecuringofthepole.Oncethepoleiserected,plumbed,andguystensioned,thecrewwilldrivetothenextfoundationsite.Dependingonhelicopterlogistics,itmaybecost‐effectivetoemploytwogroundcrewsforthisactivity.Groundcrewsandconsumableswillbemobilizedtothelinedailybyhelicopter.
7. Stringingandsettingtheconductor.Thestringinglinewillbedeployedbyhelicopter.Onceinplace,theconductorwillbestagedbyhelicopteranddeployedbygroundcrews.AHughes‐500canliftapproximately2,000feetofconductoratatime.Oncetheconductorisstrung,groundcrewswillascendeachpoletoset,tension,andfixtheconductor.Armorwrapandvibrationdamperswillbeinstalledatthistime.
C.4.5 MaintenanceMethods
Thissectiondiscussestheconceptualmaintenanceandrepairmethodsthatareappropriateforthelong‐span,tall‐poleHVDCSWERoverheadintertie.Whilesometopicsmaybegenerallyapplicabletothemaintenanceandrepairofoverheadinterties,thisdiscussionfocusesonandisspecifictothisparticularintertiedesignconcept.
Fiberglasspolescannotbeclimbedusingthespur‐and‐beltmethodcommonlyemployedtoclimbwoodpoles.Instead,apulleyandcableorropesystemwouldbeanintegralpartofthefiberglasspole.Thepulleywouldbeinstalledinthepoletop,andthecablewouldtraveldownthepoleinterior.Thelinecrewisenvisionedtouseaharnessandwinchapparatustoattachtothepoleapparatusandusethissystemtoliftalinemantothepoletopformaintenance.
Page 142
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-34
Thisapproachoffersseveraladvantagescomparedwithconventionalpoleclimbingmethods.
● Theequipmentandinherentsafetyoftheapproachenableslessexperiencedcrewstoascendthepoles.
● Pole‐topmaintenanceiseasierorpossibleduringcolderweatheroradverseconditions.
● Ascent,descent,andtop‐siteworkisfasterbecausethecrewisnotasfatigued.
● Workislessphysicallydemanding,reducingthelikelihoodoffatigue‐relatedaccidents.
Page 143
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-35
C.5 CONCEPTUALDESIGNANALYSIS
Themajorityofthedesignanalysisfortheoverheadtransmissionconceptspresentedinthisstudyfollowsestablisheddesignpracticesthatarefoundinindustryliterature.38ThissectiondiscussesspecificaspectsoftheconceptualdesignofHVDCsystemsthatareuniquetoAlaskaandwarrantmoredetaileddiscussion.
C.5.1 StructuralDesign
PolarconsultcontractedwithLineDesignEngineering,Inc.(LDE)forassistanceinthestructuralandcodeanalysisofAlaska‐specificoverheadHVDCtransmissionstructuredesignconcepts.
C.5.2 FoundationDesign
PolarconsulttaskedGolderwithdevelopingconceptualfoundationdesignsfortherepresentativesoilsandgeotechnicalconditionsdiscussedinthisreport.Golderproposedthreefoundationdesignconceptsthatprovideeconomicalfoundationoptionsforsupportingguyedpowerpolesintherepresentativegeotechnicalconditions.Thesearesummarizedbelow.
● Passivelycooledthermoprobemicropiles,installedunderthepoletoreceivecompressiveloads.ArcticFoundations,Inc.(AFI)wasidentifiedasanexperiencedmanufacturerofsuchfoundationsystems.
● Small‐diameterhelicalanchors,installedunderthepoletoreceivecompressiveloadsorinstalledattheguystoreceivetensionloads.Thermopilescouldbeinstalledadjacenttotheseanchorstodecreasetemperaturesinthebearingsoils,whichwillincreasetheanchorstrength.
● Smaller‐diameter(4‐to6‐inch)verticalpilesforbothpolesandguys,installedwithimpacthammersusingsmallertrackedrigs.Thermopilescouldbeinstalledadjacenttotheseanchorstodecreasetemperaturesinthebearingsoilsandincreasepilestrength.
Existingconventionalfoundationmethodsweremaintainedforconventionalintertielineconstruction.Thisconsistsofeitherdirectburialofawoodpoleinsuitablesoilsorfasteningawoodpoletoadrivensteelpileinthemoredifficultgeotechnicalconditions.
Forguyedpowerpoles,asetofthree1½‐inch‐diameterthermoprobemicropilesinstalledtoadepthof20feetwitha5‐footradiatorsectionabovegroundareusedastheconceptualdesignforthepolebase,andhelicalanchorsareusedastheconceptualdesignforthepoleguys.
C.5.3 AnalysisofThermoprobePerformance
PolarconsultcontractedwithZarlingAeroEngineers(ZAE)tomodeltheseasonalthermalperformanceofapassivecoolingelementsuchasathermoprobemicropile.ZAEmodeledawarmpermafrostconditionanalogoustoGolder’sgeotechnicalProfile“C”usingthickandthinorganiclayersandcurrentclimatedataformarginalpermafrostintheFairbanksarea.Thermoprobeswiththermalconductancesof1.0Britishthermalunit(Btu)/hr‐ft‐°Fand2.0Btu/hr‐ft‐°Fwereconsidered.39ZAEalsoevaluatedtheeffectofplacinga4‐inch‐thicklayerofrigidinsulationonthegroundsurfacewithin4feetofthethermoprobe.
38RepresentativepublicationsincludeRUS,2001;RUS,2003a;RUS,2009;Naidu,1996;KZK,2006;Skrotzki,1980;Southwire,2008;andThrash,2007.39The1.5‐inch‐diameter,25‐foot‐longthermoprobesinstalledattheFairbanksTestSite(seeSectionC.6ofthisappendix)haveanestimatedthermalconductanceof0.3Btu/hr‐ft‐°F(AFI,2011).
Page 144
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-36
ZAErepeatedthisanalysiswithwarmerclimateconditionstoforecasttheperformanceofthethermoprobesunderawarmingclimateinthe2060to2069decade.TheresultsoftheseanalysesaresummarizedinTableC‐8.ZAE’stechnicalanalysisandreportisincludedasAttachmentC‐1tothisappendix.
TableC‐8presentsthefollowingmodelresultsthatdirectlypertaintothestructuralperformanceofthethermoprobes:
1. Maximumdepthoftheactivelayer(occursinlatefall).Thisdefineshowmuchoftheupperportionofthethermoprobeisinthawed,structurallyweaksoilsthatprovidedlimitedlateralsupporttothethermopile.Forstructuralanalysis,thisportionofthethermoprobeisassumedtobeanunsupportedcolumnthatmustbestiffenoughtotransfercompressiveloadsfromthetopofthethermoprobedowntothepermafrostregionwithoutbuckling.
2. Averagemaximumtemperatureofthepermafrost1footfromthethermopileinearlyfall(maximumannualtemperature).Thisdefinestheminimumstrengthofthesoilaroundthethermoprobeandthebearingstrengthofthethermopiletoresistbothcompressiveandtensionloads.
TheresultsofZAE’sanalysis(TableC‐8)areexplainedbelow.Itisimportanttoemphasizethattheseresultsarespecifictothesoilparameters,thermoprobeperformance,andclimateconditionsmodeled.Othermodelinputsmayproducesignificantlydifferentresults.
1. Underthegeotechnicalconditionsmodeled,a4‐inchlayerofrigidfoaminsulationinstalledatthesurfaceandextendingradiallyoutfromthethermoprobefor4feetcanreducethemaximumdepthoftheactivelayerby1to2feet.Duetothemodeststructuralbenefit,expectedcost,anddifficultyofinstallingandmaintainingsuchaninsulationassembly,thisinsulationelementisnotincludedintheconceptualfoundationdesigns.
2. Underallgeotechnicalconditionsmodeled,thethermoprobelowersthesoiltemperatureimmediatelysurroundingthethermoprobethroughouttheyear.Thiseffectismostpronouncedduringthewintermonthswhenthethermoprobeisextractingheatfromthesoilandcoolsthesoilbyupto5°Fsurroundingthethermoprobe.Thiscoldbulbpersiststhroughthesummer,resultinginanend‐of‐summerresidualthermalanomalyofafew1/10ths°Finthesoilsurroundingthethermoprobe.Thisresultsignificantlyenhancesthecompressiveandtensioncapacityofthethermoprobeduringthewinterandspringmonthsandproducesalesser(anddecreasing)enhancementthroughthesummerandintofall.Thethermoprobeimmediatelystartscoolingthesurroundingsoilsuponthereturnoffreezingnighttimeconditionsinthelatefall.
Page 145
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-37
Table C-8 Summary of Results from Thermoprobe Modeling by ZAE
Thermoprobeconductance=1.0Btu/hr‐ft‐°F Thermoprobeconductance=2.0Btu/hr‐ft‐°F ThinOrganicLayer ThickOrganicLayer ThinOrganicLayer ThickOrganicLayer
ExistingClimateConditions (Fairbanks,1971–2000)
4”SurfaceInsulation
NoSurfaceInsulation
4”SurfaceInsulation
NoSurfaceInsulation
4”SurfaceInsulation
NoSurfaceInsulation
4”SurfaceInsulation
NoSurfaceInsulation
Maximumdepthofactivelayerwithoutthermoprobe(atthermoprobe)1 6.5feet 3feet 6.5feet 3feet
Maximumdepthofactivelayerwiththermoprobe(atthermoprobe) 5.1feet 6.5feet <1foot 3feet 5feet 6.0feet <1foot 3feet
Averageearlywintersoiltemperatureonefootfromthermoprobe 30°F 30°F 30°F 30°F 28°F 28°F 28°F 28°F
Endofsummer/earlyfalltemperaturesonefootfromthermoprobe 30‐35°F 30‐35°F 30‐32°F 30‐34°F 30‐35°F 30‐35°F 29‐33°F 29‐34°F
Projected2060‐2069ClimateConditionsforFairbanks(+2.7°Fincreaseinannualmeantemperature)
Maximumdepthofactivelayerwithoutthermoprobe(atthermoprobe)1 8feet 8feet 3.5feet 3.5feet NA NA NA NA
Maximumdepthofactivelayerwiththermoprobe(atthermoprobe) 6.5feet 7.5feet 1foot 3.5feet NA NA NA NA
Averageearlywintersoiltemperatureonefootfromthermoprobe 31°F 31°F 31.5°F 31.5°F NA NA NA NA
Endofsummer/earlyfalltemperaturesonefootfromthermoprobe 31‐37°F 31‐37°F 31‐34°F 31‐35°F NA NA NA NA
SeethefullZAEreport,AttachmentC‐1tothisappendix,formoredetailedinformation. 1 Temperatureat11feetfromthermoprobe,whichisthelimitofthemodelgraphicsinthereport.NA: Notanalyzed.
Page 146
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-38
C.5.3.1 ThermoprobeConceptualDesign
AFIdevelopedconceptualthermopiledesignsbasedonthestructuralloadsgivenfortheAlaska‐specificintertiestructures.ThedesignandfabricationsheetsfortheAFIthermopileareincludedasAttachmentC‐2.
Polefoundationsusingeitherasingle3‐inchthermopileorasetofthree1½‐inchthermopilesarebothpractical.1½‐inchthermopilescanbeinstalledbysmallerequipmentthana3‐inchpile,althoughthematerialcostandinstallationtimewillbothbesomewhathigherthanforasingle3‐inchthermopile.Onsomeprojects,theuseofsmallerequipmentisexpectedtoresultinsufficientsavingsinspiteoftheincreasedmaterialandlaborcosts.
FiguresC‐9throughC‐11presenttheadapterplatedevelopedtomateaGFRPpoletothree1½‐inchthermopiles.FigureC‐8belowshowstheprototypeinstallationofthispolefoundationdesigninstalledatthefoundationtestsiteinFairbanks.TheFairbankstestingisdescribedingreaterdetailinSectionC.6ofthisappendix.
Figure C-8 Prototype Micro-Thermopile Tripod Pole Foundation
Fairbanks,Alaska.Polarconsult,2011
Page 147
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONSPHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-39
Figure C-9 Shop Drawing of Prototype GFRP Pole Base Adapter for Micro-Thermopile Foundation (Sheet 1 of 3)
Page 148
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONSPHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-40
Figure C-10 Shop Drawing of Prototype GFRP Pole Base Adapter for Micro-Thermopile Foundation (Sheet 2 of 3)
Page 149
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONSPHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-41
Figure C-11 Shop Drawing of Prototype GFRP Pole Base Adapter for Micro-Thermopile Foundation (Sheet 3 of 3)
Page 150
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONSPHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-42
Thispageintentionallyblank.
Page 151
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-43
C.5.3.2 ScrewAnchorConceptualDesign
BasedontheconceptualdesignanalysispreparedbyGolder,screwanchorsfittedwithtwoflightsof8‐inchhelicesanddriventoadepthof10to15feetbelowthegroundsurfacewillbesuitableforanchoringmostguys.IntheconceptualsoilspresentedbyGolder,theseanchorscanbeinstalledwithatorqueof10,000to15,000foot‐pounds.Guysatanglestructuresordeadendsmayrequiretwoormoreanchors.RepresentativescrewanchorsareshownonFigureC‐12.
Figure C-12 Galvanized Screw Anchors with 8-Inch Flights
Palletofgalvanizedscrewanchorswith8‐inchflights.SimilaranchorsaresuitableforrestrainingguysforAlaska‐specifictransmissionstructuresinmanychallengingsoils.(Polarconsult,2011;PhotographcourtesyofAlaska
FoundationTechnology,Inc.)
Page 152
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-44
C.5.4 ElectricalDesign
C.5.4.1 Conductor
A1‐MWtransmissioncapacityat50kVDCequatestoanominalpeakampacityof20amperes.Overloadorfaultconditionsarehigher.TheeconomicallyallowableconductorlossesontheHVDClineweresetat3%lossesat100%nominalcapacity.Fora25‐mile,1‐MW,two‐wiremonopolarintertie,thisisapproximatelyequivalentto1.5ohmsperconductor‐mile.TherequiredconductorresistanceisthesameforamonopolarSWERtransmissioncircuit,providedthatthegroundinggridsandearthreturnpathwayhaveatotalresistanceequaltoorlessthan37.5ohms.
Thestructuralrequirementsoftheconductorarepartofalargertechnicalandeconomicanalysisoftheoverheadsystemdesign.ForruralAlaskaintertielines,longerspansandfewerfoundationswillgenerallyresultinloweroverallcapitalcosts.Thisdesigndecisioncallsforstrongerconductorstowithstandthehigherstressesfromenvironmentalloadsandtallerpolestomaintaingroundclearancesundermaximumsagconditions.
ForconventionallybuiltHVDCintertiedesignconcepts,thesedesignconsiderationsresultedintheselectionofa4/0ACSRPenguinconductorforallHVDCcircuitconfigurations.
ForAlaska‐specificHVDCintertiedesignconcepts,thesedesignconsiderationsresultedintheselectionofa19#10AlumoweldconductorforallHVDCcircuitconfigurations.
C.5.4.2 Insulators
InsulatorsinDCapplicationsaremoresusceptiblethanACinsulatorstotheaccumulationofcontaminationontheinsulatorsheds.Thisisduetothepresenceofastaticelectricfieldaroundthehigh‐voltageconductor,whichattractschargedparticlestowardtheconductor.ThisattractionofchargedparticlesresultsinmoreparticleslandingonandcontaminatingtheinsulatorthanoccursoncomparableACsystems.ThisisbecausethealternatingelectricfieldaroundanACconductordoesnotimpartanetattractiontochargedparticles.
Periodicrainsandotherweathereventscandislodgetheseparticlesfromtheinsulatorsheds.Variousspecialcoatingscanalsohelptorepelparticles.Iftheinsulatorprovidesasufficientlylongleakagepathtoaccommodatetheaccumulatedcontamination,thennoactionisrequired.Insomeclimates,itisnecessarytowashtheinsulatorsperiodically.Thiscanbedonefromsuitablyequippedhelicoptersorlinetrucks.
OnmostruralAlaskaintertielines,washinginsulatorswouldbecostprohibitive,andwhenpossible,theinsulatorsshouldbedesignedtowithstandlong‐termaccumulationofcontamination.DesignguidanceforHVDCinsulatorsindicatethatinsulatorsratedfor34.5to42kVACserviceareadequatefor50kVDC,dependingonthedegreeofenvironmentalcontaminationandself‐cleaningconditionsthatexistalongtheintertieroute.40
DuetothewiderangeofenvironmentalconditionspresentinAlaska,averyconservativeconceptualinsulatordesignhasbeenadoptedtoprovideasubstantialallowanceforinsulatorcontamination.Indiscussionswithinsulatormanufacturers,insulatorsratedfor115kVAChavebeenselectedfortheconceptualdesign.Thisprovidesaleakagepathlengththatismorethan2.7timesthepublishedguidanceforHVDCtransmissioninsulators.Specificprojectsmaybeabletorealizesomecostsavingsbyusing
40Arrillaga,1998.Page256‐257.
Page 153
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-45
lower‐voltageinsulatorsiftheyaredistantfromcoastalregions(saltspray),activerivers(blowingdust),glaciers(blowingdust),aridregions(lackofcleansingrains),andsimilargeographicorclimaticcharacteristics.
MostHVDClinesarebipolarsystemswithtwohigh‐voltageconductors(FigureC‐13).Atypicaleconomicdesignsolutionforatwo‐conductoroverheadintertielineusessuspensioninsulators.InamonopolarSWERoverheadsystem,themosteconomicaldesigncallsforalinepostinsulatoratopasinglestructure.
Figure C-13 Typical Bipolar HVDC Transmission Line Using Suspension Insulators
HVDCcrossover,NorthDakota.Source:http://upload.wikimedia.org/wikipedia/commons/b/ba/HVDC_Crossover_North‐Dakota.jpg.
Atthespans,voltages,andenvironmentalloadsconsideredforthisapplication,acompositelinepostwitha3.5‐inch‐diameterpultrudedfiberglasscoreandsiliconeshedsarenecessarytowithstandthevertical,lateral,andlongitudinalmechanicalloadsplacedontheinsulator.Aninsulatorsuchaspartno.L4‐SN321‐15UmanufacturedbyNGK,Inc.orsimilarproductsaresuitableforthisapplication.Certainloadconditions,suchasunbalancedsheddingof1‐inchradialiceona1,000‐footspan,exceedtheratedstructuralcapacityofthisinsulator.
Page 154
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-46
Forspecificprojects,thislimitationcanbeaddressedinseveralways(e.g.,lessstringentdesignloads,reducedinsulatormargin,shorterspans,etc.).Manufacturersaredevelopingstrongerlinepostinsulators(4.0‐and4.5‐inchcores)thatwillbeadequateforallloadcombinationsconsideredinthisstudy.Itisestimatedthatthesewillbecommerciallyavailableby2014orthereafter.
Alternateinsulatorconfigurationscanalsobeusedtocircumventthestructurallimitationsofexistinglinepostinsulators.FiguresC‐14throughC‐16presenttwopotentialinsulatorconfigurationsthatusesuspensioninsulatorstoreducetheloadingsonalinepostinsulator.Theseconfigurationscanbeadaptedforuseonanyoftheconceptualoverheaddesignspresentedinthisappendix.Suspensioninsulatorsarelesscostlythanthelinepostinsulators;however,thesemorecomplicatedassemblieswillrequiremorelabortoinstall.
Figure C-14 Typical Tangent Structure Using Post Insulators
CantileveredwoodpoletangentstructureforanACtransmissionline.Postinsulatorsareusedtocarryallthree‐phaseconductors.Thepost‐topinsulatorcarrieslongitudinalandlateralforcesinbending,andthetwosideinsulatorscarryverticalandlongitudinalforcesinbending.TheseapplicationsaresimilartothoseshownonFigureC‐3andFigureC‐4.
Page 155
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-47
Figure C-15 Typical Angle Structure Using Suspension and Post Insulators
GuyedsteelpoleanglestructureforanACtransmissionline.Suspensioninsulatorsareusedtocarrytheconductortension,andapostinsulatorisusedtoholdtheconductoroffofthesupportstructure.Availablepostinsulatorsarenotstrongenoughtobeusedasapost‐topinsulator(asonFigureC‐4orC‐14)inthistypeofapplication.(Polarconsult,
2012)
Page 156
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-48
Figure C-16 Typical Tangent Structure Using Suspension and Post Insulators
Cantileveredwoodpoletangentstructurefora115kVACtransmissionline.Notetheuseofasuspensioninsulatorintensionandpostinsulatorincompressiontocarrytheweightoftheconductor.Thebaseofthepostinsulatorishingedtoallowsomelongitudinalmovementoftheconductor.Thepostinsulatoralsocarriesmostofthelateralwindloadsontheconductor.Thisinsulatorconfigurationcanbeusedforsingle‐ordouble‐wireHVDCcircuitconfigurations.Aback
guycouldbeusedtoreducethenetmomentonthepoleandfoundation.(Polarconsult,2012)
Page 157
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-49
C.6 TESTINGOFOVERHEADDESIGNCONCEPTS
Mostelementsoftheconceptualoverheaddesignsdescribedinthisappendixutilizecommerciallyavailableandacceptedmaterials,designs,andconstructionmethods.CertaincomponentsoftheconceptualdesignspresentedinSectionC.5representinnovationsinoverheadlinedesignthatdonothaveaprovenrecordwithintheutilityindustry.Inordertoevaluatetheperformanceofthesecomponents,theywereinstalledatatestsiteinFairbanks,Alaska.ThissectiondescribestheobjectivesandinstallationoftheFairbanksTestSite.
C.6.1 TestObjectives
TheprimarytestobjectivesoftheFairbanksTestSitearelistedbelow.
1. Demonstrateperformanceandassemblytimeofaspliceforaconstant‐sectionGFRPutilitypole.
2. Demonstrateinstallationandperformanceofmicro‐thermopilepolefoundations.
3. Demonstrateinstallationandperformanceofmicro‐thermopileguyanchors.
4. Demonstrateinstallationandperformanceofscrewguyanchors.
5. DemonstratetheinstallationandperformanceoftheoverallguyedGFRPpolestructure.
C.6.2 TestSite
ThetestsiteislocatedonprivatepropertyoffFarmer’sLoopRoadnorthofCreamers’FieldinFairbanks.Thesiteconsistsofwarmice‐richsiltypermafrostsoils.Thesitehasanorganiclayerconsistingofdeciduousshrubsandblackspruce.Peatwaspresentatdepthsof1to5feetbelowgroundsurface.TheactivelayerinSeptemberextendedtoadepthof3feet,withstandingwaterencounteredwithinthevegetativematnearthesurface.
Geotechnicalconditionsatthesitearecharacteristicofmarginalwarmpermafrostconditions,generallyconsistentwithconceptualgeotechnicalprofile“C”developedbyGolderanddescribedinSectionCofthisappendix.
C.6.3 Installation
Keyitemsinstalledatthetestsitearedescribedinthissection.
C.6.3.1 SoilTemperatureProbes
Thesitehastwosoiltemperaturemonitoringprobes.Eachprobeisa¾‐inchPVCpipeinsertedintoadrillholethatextendsto25feetbelowgrade.Oneholeislocatedadjacent(1.0footaway)tothemicro‐thermopiletripodpolefoundationandwillbeusedtomonitorthethermaleffectsofthethermopilesandvegetationclearing.Thesecondholeislocatedapproximately50feetawayinanundisturbedblacksprucestandandwillbeusedtocollectbaselinesoiltemperaturedata.
C.6.3.2 Glass‐Fiber‐ReinforcedPolymer(GFRP)Pole
Thesitehasone60‐foot‐tallguyedglass‐fiber‐reinforcedpolymer(GFRP)pole.TheGFRPpolehasaroundsection,is12inchesindiameter,andhasa0.5‐inchwall.TheGFRPpoleismanufacturedbyPowertrusions,Inc.TheGFRPpoleconsistsofa40‐footand20‐footsectionconnectedbyafullmoment‐carryingslip‐onexternalsplice.Thesplicedoesnotrequireanyglueorsolventtodevelopbearingormomentcapacity.Bearingiscarriedbyphysicalcontactofthebutt‐endsofthepolesegments.Momentis
Page 158
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-50
carriedthroughmechanicalcontactbetweenthepoleandsplicewalls.Thespliceisheldinplaceby#14¼‐inch‐diameterx1½‐inch‐longzincplatedTekshexwasherheadscrewsdrivenaroundtheperimeterofthespliceintoeachpolesegment.ThepoleattheFairbankssiteisincompression.Powerlinepolessubjecttoupliftwouldneedtodesignthespliceconnectionfortensionloads.
C.6.3.3 GFRPPoleFoundation
TheGFRPpolefoundationisamicro‐thermopiletripodwithanadapterpiecetofitthepoleontothemicro‐thermopiles.ShopdrawingsoftheadapterpiecearepresentedonFigureC‐9throughC‐11.Theadapterpiece:
● Featuresanintegralhingeassemblytoraiseorlowerpolesinthefield,
● Providesgeneroustolerancesforbatteranglesandplacementofthemicro‐thermopiles,and
● Providesfullflexibilityinorientationofthehingeanglerelativetothetripodangle(sothepolecanberaisedorloweredinlinewithaguyanchorregardlessofhowthepolefoundationmicro‐thermopilesareoriented.
C.6.3.4 Guys
TheGFRPpoleissecuredbyfour3/8‐inchextra‐high‐strength(EHS)guylinessetat90degreestoeachotherand45degreestoground.Theguysandguyhardwareisconventional.AFUTEKmodelLSB4000loadcellisriggedintooneguywireoneachaxistomeasureguywiretension.
C.6.3.5 GuyAnchors
FourdifferentguyanchorsareinstalledattheFairbankssite.
1. A25‐foot‐longby1½‐inch‐diametermicro‐thermopile,installedata45‐degreeangletothegroundsurface(directlyin‐linewiththeguy).Thisanchorresistsguytensionsolelywithskinfriction.Theanchorisinstalledwiththetop5feetabovegroundastheradiatorsection.
2. A25‐foot‐longby1½‐inch‐diametermicro‐thermopile,installedata70‐degreeangletothegroundsurface.Thisreducedanglefromverticaliseasiertoinstallbutplacesamomentonthemicro‐thermopile.
3. Astandard8‐inchdouble‐flightscrewanchor.Thescrewanchorwasdriven15feetbelowgroundsurfaceata45‐degreeangle,placingtheanchorflightsapproximately10feetbelowgrade.
4. Astandard6‐inchswampanchor.Theswampanchorisscrewedintothesoilbyadriverodthatisthenwithdrawn.Theanchorattachestotheguywireviaagroundcable.Thistypeofanchorislesssusceptibletofrostheavethanthethreeotheranchorsdescribedabove.
C.6.4 Monitoring
Polarconsultwillcontinuetomonitortheinstallationatthetestsiteforperformance.
1. Monitorseasonalfluctuationsinsoilthermalprofilestoestablishbaselinethermalprofilesandtheperformanceofthemicro‐thermopiles.
2. Monitorguywiretensionsanddifferentialelevationsofguywiresandpolefoundationtoidentifycreepinthefoundations.
3. MonitorperformanceoftheGFRPpoleandsplice.
Page 159
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-51
Figure C-17 Installing Micro-Thermopile for Guy Anchor
ContractorGeoTekAlaska,Inc.drillingaholeforinstallationofamicro‐thermopileata45‐degreebatterangleusingaGeoProbe8040seriesdrillrig.Themicro‐thermopilewillserveasaguyanchorfortheprototypeguyedGFRPpole
installationattheFairbanksTestSite.(Polarconsult,2011).
Page 160
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-52
Figure C-18 Setting Micro-Thermopile Guy Anchor with Sand Slurry Backfill
Settingmicro‐thermopileguyanchorwithasandslurry.(Polarconsult,2011)
Page 161
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-53
Figure C-19 Installing Micro-Thermopile for Guy Anchor
ContractorGeoTekAlaska,Inc.drillingaholeforinstallationofamicro‐thermopileata45‐degreebatterangleusingaGeoProbe8040seriesdrillrig.Themicro‐thermopilewillserveasaguyanchorfortheprototypeguyedGFRPpole
installationattheFairbanksTestSite.(Polarconsult,2011).
Page 162
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-54
Figure C-20 Micro-Thermopiles Staged at Fairbanks Test Site for Installation of Prototype Foundations
1½‐inch‐diameterby25‐foot‐longmicro‐thermopilesusedforpolebaseandguyanchorsystemsforaprototypeguyedGFRPpoleinstalledattheFairbanksTestSite.Threemicro‐thermopilesareusedatthepolebase,andoneeachfortwo
ofthefourguyanchors.(Polarconsult,2011)
Page 163
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-55
Figure C-21 Micro-Thermopile Tripod for Prototype Pole Foundation
Micro‐thermopiletripodforprototypepolefoundation.Thefourthpipeatleftisasoiltemperaturemonitoringwellthatisusedtomonitorthethermal‐affectedzonearoundthethermopiles.Thereisasecondsoiltemperaturemonitoringprobelocatedapproximately40feetfromthepolebase(notshowninphoto)thatisusedtoestablishthebaseline
thermalprofileofthesite.(Polarconsult,2011)
Page 164
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-56
Figure C-22 Installing Helical Screw Anchor for Guy Anchor
ContractorCityElectric,Inc.installingahelicalscrewanchorwithtwo8‐inchflights.Theanchorwasdriven15feetintothegroundata45‐degreebatterangle.Theanchorwillbeusedtosecureoneofthefourguysontheprototype
GFRPpoleinstalledattheFairbanksTestSite.(Polaconsult,2011)
Page 165
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-57
Figure C-23 Guy Attached to Micro-Thermopile Foundation
GuywiresupportingtheinstalledprototypeGFRPpoleattheFairbanksTestSite.Theguyanchorisamicro‐thermopileinstalledata20‐degreebatterangle.Thisguywireincludesaloadcelltomonitorguywiretension.Theloadcellreaderisattachedtothecellandisvisibleinthephoto(blackandyellowdevicebelowtheguywire).Polarconsult,2011.)
Page 166
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-58
Figure C-24 Assembling the Prototype GFRP Pole Splice
ContractorCityElectric,Inc.installingthefieldsplicefortheprototypeGFRPpole.40‐footand20‐footGFRPpolesegmentsweresplicedtocreatethe60‐footpoleerectedatthesite.Thespliceslidesoverthepolesegmentsandcarriesmomentthroughcontactbetweenthepoleandsplicewalls.Verticalloadsarecarriedthroughthebuttendsofthepolesegments.Noglueoradhesiveisnecessaryforthesplicetodevelopthefullmechanicalstrengthofthepole.Thescrews
servetopreventdifferentialmovementbetweenthepoleandsplice.(Polarconsult,2011)
Page 167
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-59
Figure C-25 Installed GFRP Pole, Micro-Thermopiles, and Adapter Plate
DetailofprototypeGFRPpolebaseattheFairbanksTestSite.Thecustom‐designedbaseplateaccommodatesthevariableangleandlocationofthethreemicro‐thermopilesandincludesahingesothepolecanbeloweredifneeded.Thebaseplateallowsforadjustmentofthehingeorientationduringinstallationsoaguyanchorcanbeusedtowinch
thepoledown.(Polarconsult,2011)
Page 168
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-60
Figure C-26 Prototype GFRP Pole Foundation During Installation
DetailofprototypeGFRPpolebaseattheFairbanksTestSite.Theadapterplatewasadjustedduringinstallationsothehingeisorientedinlinewiththeguyanchorinthedistance(orangeflagging).Thisallowsuseoftheguyanchorto
lowerthepolewithawinchifneeded.(Polarconsult,2011)
Page 169
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-61
Figure C-27 Prototype Pole at the Fairbanks Test Site
ViewoftheprototypeguyedGFRPpoleinstalledattheFairbanksTestSite.Thisphotographistakenatadistanceofapproximately200yardsfromthe60‐foottallpole.(Polarconsult,2011)
Page 170
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-62
Figure C-28 Prototype Pole at the Fairbanks Test Site
ViewoftheprototypeguyedGFRPpoleinstalledattheFairbanksTestSite.Thisphotographistakenatadistanceofapproximately25yardsfromthe60‐foottallpole.Thefourguysandthepolesplicearevisibleinthisphotograph
(Polarconsult,2011)
Page 171
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-63
APPENDIXCATTACHMENTS
AttachmentC‐1:ZarlingAeroConsulting(ZAE)ThermalAnalysisofThermopile
Page 172
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-64
Thispageintentionallyblank.
Page 173
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-65
Page 174
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-66
Page 175
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-67
Page 176
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-68
Page 177
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-69
Page 178
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-70
Page 179
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-71
Page 180
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-72
Page 181
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-73
Page 182
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-74
Page 183
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-75
Page 184
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-76
Page 185
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-77
Page 186
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-78
Page 187
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-79
Page 188
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-80
Page 189
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-81
Page 190
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-82
Page 191
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-83
Page 192
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-84
Page 193
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-85
Page 194
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-86
Page 195
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-87
Page 196
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-88
Page 197
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-89
Page 198
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-90
Thispageintentionallyblank.
Page 199
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-91
AttachmentC‐2:ArcticFoundations,Inc.(AFI)ShopDrawings
Page 200
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-92
Thispageintentionallyblank.
Page 201
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-93
AttachmentC.2.1 ArcticFoundations,Inc.(AFI)ShopDrawingforPile
Page 202
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE C-94
AttachmentC.2.2 ArcticFoundations,Inc.(AFI)ShopDrawingforGuyAnchor
Page 203
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-1
APPENDIXD
CONCEPTUALDESIGNFORSUBMARINECABLES
Page 204
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-2
Thispageintentionallyblank.
Page 205
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-3
TABLEOFCONTENTS
APPENDIXDATTACHMENT...............................................................................................................................................5 ATTACHMENTD‐1:CABLETRICITYHVDCTRANSMISSIONSYSTEMSFORRURALALASKAAPPLICATIONSDCPOWERCABLES
FOR1–5MWCONVERTERS............................................................................................................................................5
Page 206
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-4
Thispageintentionallyblank.
Page 207
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-5
APPENDIXDATTACHMENT
AttachmentD‐1:CabletricityHVDCTransmissionSystemsforRuralAlaskaApplicationsDC
PowerCablesfor1–5MWConverters
Page 208
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-6
Thispageintentionallyblank.
Page 209
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-7
Page 210
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-8
Page 211
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-9
Page 212
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-10
Page 213
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-11
Page 214
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-12
Page 215
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-13
Page 216
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-14
Page 217
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-15
Page 218
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-16
Page 219
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-17
Page 220
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-18
Page 221
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-19
Page 222
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-20
Page 223
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-21
Page 224
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-22
Page 225
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-23
Page 226
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-24
Page 227
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-25
Page 228
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-26
Page 229
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-27
Page 230
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-28
Page 231
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-29
Page 232
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-30
Page 233
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-31
Page 234
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-32
Page 235
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-33
Page 236
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-34
Page 237
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE D-35
Thispageintentionallyblank.
Page 238
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-1
APPENDIXE
SWERCIRCUITSANDHVDCSYSTEMGROUNDING
Page 239
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-2
Thispageintentionallyblank.
Page 240
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-3
TABLEOFCONTENTS
E.1 SINGLE‐WIREEARTHRETURN(SWER)CIRCUITS...................................................................................7
E.2 SYSTEMGROUNDING.............................................................................................................................................7
APPENDIXEATTACHMENTS.............................................................................................................................................9 ATTACHMENTE‐1:HVDCGROUNDELECTRODEOVERVIEW...................................................................................................9 ATTACHMENTE‐2:GROUNDINGSTATIONFIGURE...................................................................................................................25
Page 241
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-4
Thispageintentionallyblank.
Page 242
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-5
LISTOFFIGURES
FigureE‐1 GroundingStation....................................................................................................................................27
Page 243
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-6
Thispageintentionallyblank.
Page 244
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-7
E.1 SINGLE‐WIREEARTHRETURN(SWER)CIRCUITS
Themosteconomicalapplicationsoflow‐powerhigh‐voltagedirectcurrent(HVDC)systemsinAlaskawillusemonopolarcircuitswithsingle‐wireearthreturn(SWER).AlaskahasadoptedtheNationalElectricSafetyCode(NESC)toregulatethedesignandinstallationofutilitygradeelectricsystems.TheNESCdoesnotallowtheuseofSWERcircuits.Thisruleisbasedonconsiderationsoflifesafety(avoidanceofsteppotentialhazards)andeconomics,asDCSWERcircuitscancauseacceleratedcorrosionofnearbyburiedmetalinfrastructuresuchaspipelines.
SWERcircuitsaresuccessfullyusedonACandDCcircuitsinmanyinternationaljurisdictions.InmanyruralAlaskaapplications,theuseofHVDCSWERcircuitsisasafeandappropriatetechnologythatcansavesignificantcosts.ThereisaprocesstoobtainwaiverstotheNESCrulesthatwillpermittheinstallationofSWERcircuits.TwoACSWERsystemsbuiltinthe1980ssuccessfullyobtainedsuchwaivers.
PolarconsultsubcontractedwiththeManitobaHVDCResearchCentre(MHRC)topreparealetterreportsummarizingthetechnicalandcodeissuesassociatedwiththeappropriateuseofSWERcircuits.ThatreportisincludedasAttachmentE‐1tothisappendix.
E.2 SYSTEMGROUNDING
Aconceptualdesignforalow‐powerHVDCgroundingstationsuitableforusewiththeproposedHVDCtransmissionsystemisincludedintheattachmenttothisappendix.
Page 245
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-8
Thispageintentionallyblank.
Page 246
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-9
APPENDIXEATTACHMENTS
AttachmentE‐1:HVDCGroundElectrodeOverview
Page 247
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-10
Thispageintentionallyblank.
Page 248
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-11
Page 249
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-12
Page 250
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-13
Page 251
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-14
Page 252
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-15
Page 253
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-16
Page 254
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-17
Page 255
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-18
Page 256
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-19
Page 257
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-20
Page 258
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-21
Page 259
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-22
Page 260
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-23
Page 261
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-24
Page 262
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-25
AttachmentE‐2:GroundingStationFigure
Page 263
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-26
Thispageintentionallyblank.
Page 264
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-27
Figure E-1 Grounding Station
Page 265
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE E-28
Thispageintentionallyblank.
Page 266
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-1
APPENDIXF
HVDCPOWERCONVERTERDEVELOPMENT
Page 267
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-2
Thispageintentionallyblank.
Page 268
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-3
TABLEOFCONTENTS
F.1 CONVERTERDEVELOPMENT.............................................................................................................................7 F.1.1 INTRODUCTION..................................................................................................................................................................7 F.1.2 CONVERTERSIZINGANALYSIS........................................................................................................................................7 F.1.3 CONVERTERTESTRESULTS...........................................................................................................................................10
F.1.3.1 FiberOpticTriggeringSysteminHigh‐VoltageTank..............................................................10 F.1.3.2 IGBTSwitchesinHigh‐VoltageTank...............................................................................................10
APPENDIXFATTACHMENTS...........................................................................................................................................13 ATTACHMENTF‐1:PPSHVDCPOWERCONVERTERREPORT...............................................................................................13
Page 269
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-4
Thispageintentionallyblank.
Page 270
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-5
LISTOFFIGURES
FigureF‐1 TypicalLoadDurationProfileforanAlaskaVillage....................................................................8
FigureF‐2 PeakLoadsinAlaskaVillages(2007–2009).................................................................................9
Page 271
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-6
Thispageintentionallyblank.
Page 272
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-7
F.1 CONVERTERDEVELOPMENT
F.1.1 Introduction
Thehigh‐voltagedirectcurrent(HVDC)converterdevelopedunderthisprojectisa1‐megawatt(MW)powerconvertercapableofbidirectionalpowerconversionbetweenthree‐phase480voltsalternatingcurrent(VAC)and50kilovolts(kV)HVDC.TheconvertercapacityisappropriatetosupplytheelectricalneedsofmostAlaskavillages.Incontrast,existingHVDCpowerconvertersystemsareonlycosteffectiveatmuchlargertransmissioncapacities,startingatapproximately50MWandextendingupto1,000sofMWsofcapacity.
MultipleHVDCconverterscanbe“paralleled”toachievehigherpowertransmissioncapacitieswhereneeded.BasedonPhaseIIdevelopmentwork,thepriceofacommerciallyproduced1‐MWHVDCpowerconverterisestimatedtobe$250,000.Atleasttwo1‐MWconvertersareneededforacomplete1‐MWHVDCtransmissionsystem.
ThisappendixpresentsPrincetonPowerSystems,Inc.’s(PPS’s)finaldeliverablesforconverterspecification,design,andtestplanunderPhaseIIoftheHVDCtechnologydevelopmentprogram(AttachmentF‐1).
PPShassuccessfullydemonstratedoperationoftheprototypeconvertersatthefull50kVDCandpowerflowinbothinverter(HVDCtoAC)modeandrectifier(ACtoHVDC)modeinacontrolledtestfacilitysetting.Thesetestingeffortsvalidatethedesignandbasicfunctionalityoftheconverter.
Inthecourseoftesting,PPSidentifiedtwohardwareproblemsthatpreventedfull‐powertestingoftheprototypeconverters.PPShasinvestigatedtheseproblemsandidentifiedtheactionsnecessarytocorrectbothproblems.TheproblemsandsolutionsarediscussedinAttachmentF‐1tothisappendix.
PPSiscontinuingtoworkonthehardwaremodificationsneededtocorrectthepriortechnicalproblems.Duetothelonglead‐timetoobtainsuitablereplacementinsulatedgatebipolartransistor(IGBT)switches,theconvertermodificationsandtestingarenotexpectedtobecompleteduntillate2012.PPSwillissueasupplementalreportdetailingtheresultsoffinalPhaseIItestingwhentestingiscompleted.ThissupplementalreportandthefullyoperationalconverterswillbePPS’sfinaldeliverableunderPhaseIIofthisresearchanddevelopment(R&D)project.
F.1.2 ConverterSizingAnalysis
TheelectricalloadcharacteristicsofruralAlaskancommunitiesthatarethetargetofthisprojectwereevaluated.ThecapacityoftheHVDCintertiesystemwasbasedonthelikelypeakloadsandloaddurationprofilesoftheselectedcommunities.
Thedurationofpeakloadsprovidesaneconomicbasisfordesigncapacityoftheintertie.Ingeneral,theintertieisdesignedtominimizethelinelossesatpeakloads.TheloaddurationprofileforHooperBayispresentedonFigureF‐1.ThisprofileisrepresentativeofruralAlaskancommunitieswithapeakloadof760kW,andwillgenerallyapplytoothercommunities.Somecommunities,suchasthosewithfishprocessors,willhaveloadprofilesdifferentthanthatshownonFigureF‐1.
Page 273
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-8
Figure F-1 Typical Load Duration Profile for an Alaska Village
0
100
200
300
400
500
600
700
800
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percent of Time Load is Equaled or Exceeded
Sys
tem
Lo
ad i
n k
W
Polarconsult,201241
ThepeakloadsofruralAlaskacommunitiesparticipatinginthePowerCostEqualization(PCE)programwerereviewedtodeterminetheappropriatepowercapacityfortheHVDCintertiesconsideredforthisstudy.ThedistributionofpeakloadsispresentedonFigureF‐2.
Basedonthisanalysis,a1‐MWpowerintertieisanappropriateconceptualcapacityforthemajorityofruralAlaskainterties.Formaximumreliabilityandflexibility,thepowerconverterspecificationscallfora1‐MWunitcomprisedoftwo500‐kWmodulesoperatinginparallel.Theconvertermodulescanbeconnectedtooperateinparallel,thusprovidingadditionalcapacityuptoafewMWswherenecessary.IntertiesdesignedformorethanafewMWsmaywarrantreevaluationoftheACinterfacevoltage(480volts[V]forthe500‐kWpowerconvertermodule).
41DatageneratedforHooperBayusingtheAlaskaVillageElectricLoadCalculator(NREL,2005)
Page 274
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-9
Figure F-2 Peak Loads in Alaska Villages (2007 – 2009)
0
1000
2000
3000
4000
5000
Point L
ayNak
nek
Bethel
/ Osc
arville
Craig
Kotzeb
ueDillin
gham
Haines
Alakan
uk
Tok / T
anac
ross
Ambler
Galena
Deerin
gPoin
t Hop
eSt. P
aul
Nuiqsu
tWale
sKak
tovik
Selawik
Atmau
tluak
Fort Y
ukon
Kasigl
ukHoo
per B
ay
Tokso
ok BayAnia
kTog
iak
Mounta
in Villa
geChe
vak
Gambe
llKipn
ukNap
askia
kKotl
ikPilo
t Stat
ionBuc
kland
Ouzink
ie
New Stuy
ahok
Shishm
aref
Gustav
usKwigi
llingo
kMars
hall
Healy
Lake
Kongig
anak
Stebbin
sNort
hway
Manok
otak
Mekory
ukTell
erHus
liaElfin
Cov
eNun
apitc
huk
Kokha
nok B
ayTuk
uksa
kSha
ktooli
kBea
ver
Hughe
s
Tenak
ee Spri
ngs
Minto
Nunam
Iqua
Goodn
ews B
ay
Port Alsw
orth
Leve
lock
Pilot P
oint
Eagle
/ Eag
le Villa
geGray
ling
AtkaRub
ySlee
tmute
Manley
Hot
Spring
s
Crooke
d Cree
k
Chuath
baluk
Chignik
Lake
Lime V
illage
Tetlin
Takotn
aVen
etie
Mentas
taCirc
lePed
ro Bay
Igiug
igKarl
ukRed
Dev
ilAda
kCen
tral
Dot La
keEkw
okKak
eKob
ukNap
akiak
Tunun
ak
Community
Pea
k P
ow
er
De
man
d (
kW)
(2) 1 MW HVDC CONVERTERS USED FOR BIPOLAR INTERTIE, ADEQUATE FOR 82% OF COMMUNITIES.
1 MW HVDC CONVERTER, ADEQUATE FOR 76% OF COMMUNITIES.
1 MW HVDC CONVERTER WITH 500KW MODULE FAILURE, ADEQUATE FOR 60% OF COMMUNITIES.
Source: 2009 Power Cost Equalization Data, Alaska Energy Authority
Page 275
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-10
F.1.3 ConverterTestResults
Inthecourseoftestingtheprototypeconverters,PPShassuccessfullydemonstratedoperationatthefull50kVDCandpowerflowinbothinverter(HVDCtoAC)modeandrectifier(ACtoHVDC)mode.Inthecourseoftesting,PPSidentifiedtwohardwareproblemsthatpreventedcompletionofPhaseIItestingoftheprototypeconverters,includingdemonstrationoffullpoweroperation.PPShasinvestigatedtheseproblemsandidentifiedtheactionsnecessarytocorrectbothproblems.Theproblemsandsolutionsaresummarizedbelow.
F.1.3.1 FiberOpticTriggeringSysteminHigh‐VoltageTank
Afiberopticnetworkisusedtotriggerthesolid‐stateIGBTswitchesinsidethehigh‐voltagetank.Testingrevealedproblemswiththetriggeringtimingandreliabilityofthistriggeringsystem.Investigationdeterminedthatthelensesusedinthefiberopticsystemexhibitexcessivelyhighsignalloss,causingtheobservedtimingandreliabilityissues.PPShasidentifiedandtesteddifferentlensesandisproceedingtoreplacethelensesinbothprototypeconvertermodulestosolvethisproblem.
F.1.3.2 IGBTSwitchesinHigh‐VoltageTank
TheIGBTswitchesinthehigh‐voltagetankwerefoundtoenterthermalrunawaywhentheprototypeconverterisoperatedatlow‐powerlevelsininverter(HVDCtoAC)mode.Investigationhasdeterminedthattheseswitchesdonotperforminaccordancewiththemanufacturer’sspecifications.Consultationswiththemanufacturerhasnotproducedanacceptableremedy,andPPShasconcludedthattheseIGBTscannotbeusedforthisapplication.PPShasidentifiedalternateIGBTsthatmeetthetechnicalandeconomiccriteriaofthisproject,andisproceedingtoupgradetheconverterswiththeseswitches.Becausetheswitchesoperateatadifferentvoltagethantheoriginalswitchesandhaveadifferentformfactor,redesignofthehigh‐voltagestageboardsisnecessary.
Becauseofthehardwareproblemsidentified,PPShasnotyetcompletedconvertertesting.FinaltestingispendingreceiptofnewIGBTs.
FigureF‐3showsasimplifiedschematicillustratingthecurrentdevelopmentstatusoftheconverter’sbasicfunctionalmodes.
Page 276
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-11
Figure F-3 Simplified Schematic Illustrating Technical Progress
Page 277
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-12
Thispageintentionallyblank.
Page 278
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-13
APPENDIXFATTACHMENTS
AttachmentF‐1:PPSHVDCPowerConverterReport
Page 279
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-14
Thispageintentionallyblank.
Page 280
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-15
Page 281
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-16
Page 282
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-17
Page 283
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-18
Page 284
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-19
Page 285
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-20
Page 286
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-21
Page 287
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-22
Page 288
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-23
Page 289
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-24
Page 290
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-25
Page 291
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-26
v
Page 292
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-27
Page 293
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-28
Page 294
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-29
Page 295
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-30
Page 296
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-31
v
Page 297
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-32
Page 298
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-33
v
Page 299
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-34
Page 300
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-35
Page 301
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-36
Page 302
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-37
Page 303
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-38
Page 304
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-39
Page 305
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-40
Page 306
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-41
Page 307
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-42
Page 308
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-43
Page 309
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-44
Page 310
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-45
Page 311
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-46
Page 312
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-47
Page 313
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-48
Page 314
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-49
Page 315
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-50
Page 316
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-51
Page 317
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-52
Page 318
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-53
Page 319
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-54
Page 320
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-55
Page 321
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-56
Page 322
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-57
Page 323
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-58
Page 324
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-59
Page 325
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-60
Page 326
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-61
Page 327
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-62
Page 328
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-63
Page 329
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-64
Page 330
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-65
Page 331
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-66
Page 332
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-67
Page 333
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-68
Page 334
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-69
Page 335
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-70
Page 336
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-71
Page 337
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-72
Page 338
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-73
Page 339
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-74
Page 340
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-75
Page 341
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-76
Page 342
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-77
Page 343
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-78
Page 344
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-79
Page 345
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-80
Page 346
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-81
Page 347
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-82
Page 348
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-83
Page 349
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-84
Page 350
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-85
Page 351
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-86
Page 352
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-87
Page 353
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-88
Page 354
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-89
Page 355
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-90
Page 356
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-91
Page 357
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-92
Page 358
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-93
Page 359
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-94
Page 360
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-95
Page 361
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-96
Page 362
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-97
Page 363
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-98
Page 364
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-99
Page 365
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-100
Page 366
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-101
Page 367
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-102
Page 368
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-103
Page 369
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-104
Page 370
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-105
Page 371
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-106
Page 372
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-107
Page 373
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-108
Page 374
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-109
Page 375
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-110
Page 376
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-111
Page 377
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-112
Page 378
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-113
Page 379
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-114
Page 380
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-115
Page 381
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-116
Page 382
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-117
Page 383
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-118
Page 384
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-119
Page 385
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-120
Page 386
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-121
Page 387
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-122
Page 388
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-123
Page 389
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-124
Page 390
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-125
Page 391
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-126
Page 392
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-127
Page 393
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-128
Page 394
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-129
Page 395
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-130
Page 396
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-131
Page 397
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-132
Page 398
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-133
Page 399
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-134
Page 400
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-135
Page 401
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-136
Page 402
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-137
Page 403
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-138
Page 404
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-139
Page 405
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-140
Page 406
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-141
Page 407
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-142
Page 408
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE F-143
Page 409
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-1
APPENDIXG
HVDCSYSTEMPROTECTION,CONTROLS,ANDCOMMUNICATIONS
Page 410
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-2
Thispageintentionallyblank.
Page 411
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-3
TABLEOFCONTENTS
G.1 INTRODUCTION........................................................................................................................................................7 G.1.1 POINT‐TO‐POINTSYSTEMS.............................................................................................................................................7 G.1.2 MULTITERMINALHVDC(MTDC)SYSTEMS...............................................................................................................7
G.2 PROTECTIVEHARDWARE...................................................................................................................................7
G.3 COMMUNICATIONS.................................................................................................................................................7 G.3.1 FAULTDETECTION............................................................................................................................................................8 G.3.2 INFRASTRUCTURE..............................................................................................................................................................8
G.4 OVERHEADINTERTIECOMMUNICATIONOPTIONS................................................................................9 G.4.1 OPTICALGROUNDWIRE..................................................................................................................................................9 G.4.2 POWERLINECARRIER......................................................................................................................................................9 G.4.3 WRAPPEDFIBER‐OPTICCABLE......................................................................................................................................9 G.4.4 SEPARATETELECOMUNDERBUILD................................................................................................................................9
G.5 UNDERGROUNDCABLEINTERTIEOPTIONS..............................................................................................9
G.6 SUBMARINECABLEINTERTIEOPTIONS....................................................................................................10
G.7 BROADBANDINTEGRATION............................................................................................................................10
APPENDIXGATTACHMENTS...........................................................................................................................................11 ATTACHMENTG‐1:MHRCTASK3,HVDCSTATIONHARDWARERECOMMENDATIONS..................................................11 ATTACHMENTG‐2:MHRCTASK2,MULTI‐TERMINALHVDCTECHNICALREVIEW........................................................25 ATTACHMENTG‐3:MHRCTASK5,CARRIERCOMMUNICATIONS........................................................................................45
Page 412
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-4
Thispageintentionallyblank.
Page 413
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-5
LISTOFTABLES
TableG‐1 CommunicationsOptionswithHVDCInterties.........................................................................G‐8
Page 414
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-6
Thispageintentionallyblank.
Page 415
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-7
G.1 INTRODUCTION
Thisappendixdiscusseselectricalprotection,controls,andcommunicationsrequirementsneededtooperatethehigh‐voltagedirectcurrent(HVDC)systemsdiscussedinthisreport.Therearecertainminimumprotection,control,andcommunicationprovisionsrequiredofanyHVDCsystem.
Initssimplestform,theprotection,controls,andcommunicationsprovisionsmaybemanuallyoperated.Thisapproachissimplertomanageandlesscostlytoinstallandmaintainthanfullyautomatedsystems,butisgenerallylimitedtopoint‐to‐pointinterties.
Theprotection,controls,andcommunicationsneedsofmorecomplexmultiterminalHVDC(MTDC)systemsrequirestheuseofautomatedcontrolsforoperation.Therequirementforautomatedcapabilitiesaremorecostlyandcomplicatedtooperate.
G.1.1 Point‐to‐PointSystems
ManyruralHVDCintertiesmaybenefitfromapoint‐to‐pointHVDCsystem.Low‐power(<1MW)point‐to‐pointmonopolarHVDCsystemscanautomaticallyregulatepowerflowovertheHVDCsystembymonitoringtheHVDCvoltage.Nocommunicationsbetweentheconvertersareneededtoachievethisbasicpowertransferfunction.Existingcommercialtelecommunicationsnetworksinthecommunitiescanbeusedtoprovidesomedegreeofmonitoringandcontrolfunction.
G.1.2 MultiterminalHVDC(MTDC)Systems
MTDCnetworksbydefinitionhavemorethantwoHVDCconverterstationsconnectedtoagivenHVDCline.EachoftheconverterstationsiscapableofaddingorsubtractingpowerfromtheHVDCline.
MTDCnetworksareprojectedtobethelowestcostintertiesolutionformanyoftheruralenergynetworksunderconsideration.Theseregionsincludeinterconnectionofseveralsoutheastcommunities,theadjacentcommunitiesintheYukon‐KuskokwimDelta,andothersintheBristolBayarea.Accordingly,thetechnicalfeasibilityofMTDCnetworksisofparticularinterestforAlaska’sutilityindustry.
G.2 PROTECTIVEHARDWARE
RecommendationspreparedbytheManitobaHVDCResearchCentre(MHRC)discussthegeneralDC‐sideHVDCconverterstationhardwarenecessaryforbasicoperationandprotectionoftheHVDCsystem.ThisinformationispresentedinAttachmentG‐1tothisappendixandistitled“TechnicalNoteonHVDCStationHardware.”
ProtectiveAC‐sidehardwarewillincludefusesorbreakers,disconnects,andcontrolsasneededtointegratewiththelocalgeneratingplant.Project‐specificdesignisnecessaryastheseinterfacescanrangefrombasicandmanuallyoperatedtohighlyintegratedandautomated,dependingontheneedsoftheparticularapplication.ThepowerconvertersdevelopedbyPPSsupportstandardcommunicationprotocolstoallowintegrationwithoverallcontrolsystems.
G.3 COMMUNICATIONS
Communicationsareusedformonitoringofconverterstationstatus,economicdispatchofdistributedgenerationassets,faultdetectionontheHVDCnetwork,andrelatedutilityfunctions.Systemsoftenincludededicatedvoiceanddatacircuitstofacilitatecommunicationsbetweendifferentpartsoftheutilitytransmissionnetwork.
Page 416
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-8
G.3.1 FaultDetection
WithoutdifferentialcurrentmonitoringbetweentheHVDCconverterstations,ifthetotalcurrentintotheHVDCsystem(faultcurrent+loadcurrent)islessthantheratedsystemcurrent(20amperesfora1‐MWintertie),therectifyingconverterwillnotbeabletodistinguishthefaultloadfromanormalloadandwillcontinuetoinputpowerintotheHVDClinetomaintaintheHVDCvoltage.Ifthefaultcurrentishighenoughtoexceedthecapacityoftherectifyingconverter,thentheconverterwilltripandannounceafault.
Theresultisthatalowimpedancefaultcangenerallybedetectedbytheanomalouslyhighpowerdraw,whereasahighimpedancefaultcanremainundetectedindefinitelywiththisscheme.Timelydetectionandcorrectionisthereforedesirablewherepractical.
ACsystemsexperiencesimilarproblemsdetectinghighimpedancefaults,sothistypeofriskisnotwithoutprecedentonutilitysystems.Theremotenessandlackofpeopleinthevicinityofthesetransmissionlinesisafactorthatshouldbeconsideredwhenutilitiesevaluatethisrisk.Aproject‐specificanalysisshouldbeconductedforeveryintertietoevaluatethecostoffaultdetectioncapabilitiesagainsttherisksassociatedwithundetectedfaults.
Detectionofpersistenthighimpedancefaultsrequires,ataminimum,slow‐speedcommunicationbetweentheconverterstationsanddifferentialcurrentmonitoring.Ifthefaultimpedanceissohighthatthefaultcurrentisbelowtheerrorofthedifferentialcurrentdetectionmethod(ascouldbethecaseforadownedconductorlyingonice,forexample),thefaultmayremainunnoticedevenwiththisdetectionregimeinplace.Theonlypracticalwaytoidentifysuchfaultsisbyphysicalinspectionoftheintertieline.FaultdetectionisdiscussedintheMHRCTechnicalNoteonHVDCStationHardwareRecommendationsincludedasAttachmentG‐1tothisappendix.
G.3.2 Infrastructure
AllremoteAlaskacommunitieshaveaccesstobasictelephoneserviceandbroadbandinternetservice.Ataminimum,theseservicesareprovidedthroughgeosynchronoussatelliteplatforms.Dependingontheprojectlocation,communitiesmaybeservedbyexistingmicrowaverelaysystems,copperwirenetworks,fiber‐opticnetworks,oracombinationofthese.
Theslowestcommunicationoptionavailablestatewideisgeosynchronoussatellite‐basedcommunicationswithaninherentlatencyofatleast250millisecondsforone‐waycommunications.Thislatencyarisesfromthetraveltimeforasignaltoreachtheorbitingsatelliteandreturntoearth.SignalprocessingattheEarthstationsoraboardthesatelliteaddtothislatency.
Thiscommunicationsmethodwouldbesufficientforabasicdifferentialcurrentmonitoringprotocolandforcertainsupervisorycontrolanddataacquisition(SCADA)functionsforanHVDCintertie.
Optionsforintegrateddedicatedcommunicationscircuitsarediscussedin‘TechnicalNoteonCarrierCommunications,”preparedbyMHRC,includedasAttachmentG‐3tothisappendix.
Thecost‐effectivenessofsuchoptionswilldependonthetypeofHVDCintertie,andonthespecificconfigurationoftheHVDCline.TableG‐1summarizesthethreebasicHVDCintertieconfigurationsandpotentiallysuitablecommunicationstechnologiesforeach.
Table G-1 Communications Options with HVDC Interties
Intertie Type Communications Option
Page 417
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-9
Overhead Conductor Optical Ground Wire (OPGW) Carrier
Wrapped fiber-optic cable Separate telecom underbuild
Underground Cable Separate fiber-optic cable in same trench Fiber-optic circuit bundled into power cable
Submarine Cable Fiber-optic cable in conductor tube Fiber-optic cable in armor strand
G.4 OVERHEADINTERTIECOMMUNICATIONOPTIONS
G.4.1 OpticalGroundWire
Opticalgroundwire(OPGW)isatypeofelectricalconductorthathasaluminumconductorstrandssurroundingastainless‐steeltubeattheconductor’score.Opticalfibersareroutedthroughthestainless‐steeltube.OPGWiscommonlyusedasanoverheadgroundingwireonACtransmissiontowersforlightningprotection.
Dependingontheapplication,OPGWmaybesuitableforuseasthecurrent‐carryingconductoronanHVDCtransmissionline.Onepotentiallysignificantdrawbackwouldbetheincreasedcomplexityofrepairingconductorbreaksduetothestainless‐steeltubeandopticalfibers.Theneedforspeciallytrainedpersonnelandequipmenttorepairthistypeofconductorcouldsignificantlydelaytherepairofaconductorbreak,reducingthereliabilityofthetransmissionline.
TheMHRCTechnicalNoteincludedasAttachmentG‐3tothisappendixdiscussesOPGWapplicationsinmoredetail.
G.4.2 PowerLineCarrier
Powerlinecarrier(PLC)isameansofusingacurrent‐carryingconductorinanintertiecircuittocarryadatasignalaswell.Acoilisusedtomagneticallyinduceadatawaveformontotheconductor,andasecondcoilisusedtoreceivethewaveform.PLCsystemshavebeenimplementedonHVDCcircuitsandarediscussedintheMHRCTechnicalNoteinAttachmentG‐3.
G.4.3 WrappedFiber‐OpticCable
Opticalfiberpackagesareavailablethatcanbewrappedoveramessengerwire,suchasthepowerconductor.Therearetwopotentialdrawbackswiththisoption.Thefirstisthattheopticalfibercablewouldincreasethewindexposureandicingsurfaceoftheconductor,increasingenvironmentalloadingsontheoverheadsystem.Thesecondisthatthepresenceoftheopticalfibercablewouldcomplicatetherepairofbrokenconductors.
G.4.4 SeparateTelecomUnderbuild
DependingonthetypeofoverheadlineconstructionusedfortheHVDCintertieline,aconventionaltelecommunicationsunderbuildmaybeappropriate.Thiscouldusefiberorcopperdependingonthespecificcircumstances.
G.5 UNDERGROUNDCABLEINTERTIEOPTIONS
Page 418
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-10
ThemoststraightforwardmeansofaddingcommunicationstoanundergroundcableHVDCintertieistoincludeaseparatefiber‐opticorcoppercable.Fiberopticswouldbepreferredifasingle‐wireearthreturn(SWER)circuitisused,asitwouldnotpickupthereturncurrent.Conventionaldesignandconstructionpracticesaresuitableforinstallationofco‐locatedundergroundcommunicationandpowercables.
G.6 SUBMARINECABLEINTERTIEOPTIONS
Therearethreegeneraloptionsforbundlingtelecommunicationswithsubmarinepowercables.Allthreeutilizefiberoptics,andareacceptedpracticeforsubmarinepowerand/ortelecommunicationcables.Thesemethodsare:
● Replacingoneormoreofthearmorwiresonthesubmarinecablewithahollowstainless‐steeltubeandroutingopticalfibersthroughthetube(s).
● Utilizingahollowcoppertubeasthecurrent‐carryingconductorandroutingopticalfiberswithinthecoppertube.Thisisacommoncableconstructionontransoceanicfiber‐opticcables.
● Insertingastainless‐steeltubebetweentwolayersofthesubmarinecable,typicallybetweentheleadsheath(ifsoequipped)andthepolyethyleneoutercablejacket.Opticalfibersareroutedthroughthistube.
G.7 BROADBANDINTEGRATION
ThereisanopportunitytointegratebroadbandcommunicationswithcertainHVDCintertieprojects.Wherefeasible,combiningpowerandtelecommunicationsconnectivityintoasingleprojectcansignificantlyincreasethebenefitsofanintertieprojectanddeliverbothcapabilitiesatalowercostthanpossiblethroughindividualprojects.
Thisopportunityisparticularlypromisingforundergroundandsubmarinecableapplications.Inmanyapplications,theincrementalcostofincludingafiberopticbundlewitheitherpowercableisexpectedtobemodestcomparedtotheresultingbenefits.AttachmentD‐1discussesthisopportunityinthecontextofsubmarinecables.
Page 419
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-11
APPENDIXGATTACHMENTS
AttachmentG‐1:MHRCTask3,HVDCStationHardwareRecommendations
Page 420
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-12
Thispageintentionallyblank.
Page 421
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-13
Page 422
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-14
Page 423
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-15
Page 424
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-16
Page 425
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-17
Page 426
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-18
Page 427
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-19
Page 428
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-20
Page 429
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-21
Page 430
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-22
Page 431
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-23
Page 432
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-24
Thispageintentionallyblank.
Page 433
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-25
AttachmentG‐2:MHRCTask2,Multi‐TerminalHVDCTechnicalReview
Page 434
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-26
Thispageintentionallyblank.
Page 435
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-27
Page 436
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-28
Page 437
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-29
Page 438
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-30
Page 439
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-31
Page 440
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-32
Page 441
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-33
Page 442
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-34
Page 443
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-35
Page 444
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-36
Page 445
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-37
Page 446
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-38
Page 447
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-39
Page 448
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-40
Page 449
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-41
Page 450
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-42
Page 451
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-43
Page 452
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-44
Thispageintentionallyblank.
Page 453
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-45
AttachmentG‐3:MHRCTask5,CarrierCommunications
Page 454
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-46
Thispageintentionallyblank.
Page 455
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-47
Page 456
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-48
Page 457
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-49
Page 458
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-50
Page 459
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-51
Page 460
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-52
Page 461
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-53
Page 462
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-54
Page 463
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-55
Page 464
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-56
Page 465
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-57
Page 466
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-58
Page 467
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-59
Page 468
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-60
Page 469
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-61
Page 470
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE G-62
Thispageintentionallyblank.
Page 471
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-1
APPENDIXH
CANDIDATEHVDCSYSTEMDEMONSTRATIONPROJECTS
Page 472
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-2
Thispageintentionallyblank.
Page 473
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-3
TABLEOFCONTENTS
H.1 INTRODUCTION........................................................................................................................................................7
H.2 DEMONSTRATIONPROJECTOBJECTIVES.....................................................................................................7
H.3 CRITERIAFORDEMONSTRATIONPROJECTSITES...................................................................................8
H.4 POTENTIALDEMONSTRATIONPROJECTS.................................................................................................10 H.4.1 SUMMARYOFPROJECTSCONSIDERED.........................................................................................................................10 H.4.2 HVDCDEMONSTRATIONPROJECTSONEXISTINGACDISTRIBUTIONLINES.......................................................12
H.4.2.1 DillinghamtoAleknagikACLineConversion(DemonstrationOnly)...............................12 H.4.2.2 EurekaACLineConversion(DemonstrationOnly)..................................................................12 H.4.2.3 HopeSubstationtoHopeACLineConversion(DemonstrationOnly).............................12 H.4.2.4 Homer–SeldoviaACLineConversion(DemonstrationOnly)............................................13
H.4.3 HVDCDEMONSTRATIONPROJECTSONNEWACDISTRIBUTIONLINEEXTENSIONS.........................................13 H.4.3.1 GVEAPhillipsRoadLineExtension..................................................................................................14 H.4.3.2 GVEACummingsRoadLineExtension...........................................................................................14 H.4.3.3 MEAtoIndependenceMineLineExtension.................................................................................14
H.4.4 HVDCINTERTIEPROJECTS...........................................................................................................................................15 H.4.4.1 BarrowtoAtqasukHVDCIntertie.....................................................................................................15 H.4.4.2 NometoTellerandBrevigMissionHVDCIntertie....................................................................15 H.4.4.3 PilgrimHotSpringstoNomeHVDCIntertie................................................................................15 H.4.4.4 St.Michaels–StebbinsHVDCIntertie.............................................................................................16 H.4.4.5 St.Mary’stoMountainVillageHVDCIntertie..............................................................................16 H.4.4.6 DillinghamtoManokotakHVDCIntertie.......................................................................................16 H.4.4.7 NewStuyahok–EkwokHVDCIntertie...........................................................................................16 H.4.4.8 Kodiak–OuzinkieHVDCIntertie......................................................................................................16 H.4.4.9 Green’sCreektoHoonahHVDCIntertie........................................................................................17 H.4.4.10 PetersburgtoKakeHVDCIntertie....................................................................................................17 H.4.4.11 GustavustoGlacierBayNationalParkIntertie(HVDCDemonstrationOnly)..............17
H.4.5 PROJECTMAPS.................................................................................................................................................................18
Page 474
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-4
Thispageintentionallyblank.
Page 475
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-5
LISTOFTABLES
TableH‐1 TypesofHVDCDemonstrationProjectsandFactorsforEach................................................9
TableH‐2 PotentialHVDCDemonstrationProjects........................................................................................10
Page 476
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-6
LISTOFFIGURES
FigureH‐1 LocationMapforPotentialDemonstrationProjectSites........................................................11
FigureH‐2 VicinityMapforDemonstrationProjectsnearDillingham.....................................................18
FigureH‐3 VicinityMapforEurekaACLineConversion................................................................................19
FigureH‐4 VicinityMapforHopeACLineConversion...................................................................................20
FigureH‐5 VicinityMapforSeldoviaACLineConversion.............................................................................21
FigureH‐6 VicinityMapforDeltaJunctionACLineExtension....................................................................22
FigureH‐7 VicinityMapforDeltanaACLineExtension.................................................................................23
FigureH‐8 VicinityMapforIndependenceMineACLineExtension.........................................................24
FigureH‐9 VicinityMapforBarrow–AtqasukHVDCIntertie.....................................................................25
FigureH‐10 VicinityMapforDemonstrationProjectsnearNome...............................................................26
FigureH‐11 VicinityMapforSt.Michaels–StebbinsHVDCIntertie...........................................................27
FigureH‐12 VicinityMapforSt.Mary’s–MountainVillageHVDCIntertie..............................................28
FigureH‐13 VicinityMapforNewStuyahok–EkwokHVDCIntertie..........................................................29
FigureH‐14 VicinityMapforKodiak–OuzinkieHVDCIntertie.....................................................................30
FigureH‐15 VicinityMapforGustavusandHoonahHVDCInterties...........................................................31
FigureH‐16 VicinityMapforKake–PetersburgHVDCIntertie....................................................................31
Page 477
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-7
H.1 INTRODUCTION
Thisreportincludestheevaluationofpotentialprojectsfordemonstrationofthehigh‐voltagedirectcurrent(HVDC)technologyinPhaseIII.Thiseffortconsistedofthefollowingmajoractivities:
● Definingtheprimaryobjectivesofademonstrationproject;
● Definingthekeycriteriaforcandidateprojects;
● Identifyingpotentialintertieprojects;
● Contactinglocalstakeholderstogatherinformationaboutthoseprojects;and
● EvaluatingtheprojectsforsuitabilityasademonstrationofthisHVDCtechnology.
Thisappendixsummarizesandpresentsthefindingsfromtheseactivities.Aspecificsitehasnotbeenselectedforademonstrationprojectatthistime.Polarconsultwillcontinuetoworkwiththevariousprojectstakeholderstoidentifyaspecificdemonstrationprojectinthefuture.
H.2 DEMONSTRATIONPROJECTOBJECTIVES
PolarconsultworkedwiththeStakeholder’sAdvisoryGroup(SAG),individualstakeholders,Polarconsultsubcontractors,andotherinterestedentitiesoverthecourseofPhaseIItorefinetheobjectivesofthePhaseIIIdemonstrationprojectfortheproposedHVDCsystem.
Definingtheseobjectiveswasamajortopicofdiscussionatthe2ndSAGMeeting,heldinAnchorageonJanuary14,2011.AseriesofconferencecallswereheldwithmembersoftheSAGinJanuaryandFebruary2011torefinetheobjectivesofthedemonstrationprojectandthecandidatesitesidentifiedbyPolarconsult.
Theseeffortsestablishedthefollowingaskeyobjectivesofthedemonstrationproject:
● FacilitateexpeditiousadvancementoftheproposedHVDCsystem.Ademonstrationprojectthatcannotbeimplementedforyearsduetoprohibitivecost,regulatoryimpediments,orsimilarfactorscouldundulydelaycommercialacceptanceofthesystemandwidespreaddeploymentinAlaska.
● Demonstratetostakeholders(Alaskautilities,policymakers,regulators,etc.)thattheHVDCconverterisfunctional,robust,andpracticalunderthelogistical,electrical,andenvironmentaloperatingconditionstypicalofruralAlaskaapplications.
● Demonstratethatinnovativeaspectsofthetransmissionlineconstruction,suchasuseofsingle‐wireearthreturn(SWER)circuitsinpermafrostregions,newoverheadlinedesignsormaterials,andsimilarsystemelementsarereliable,cost‐effective,andappropriateforruralAlaskaintertieapplications.
OneofthekeyinsightsprovidedbytheSAGwasthatthecommercializationplanfortheproposedsystem,includingthedemonstrationphase,shouldbedesignedinameasuredmannerthatincrementallydemonstratesandprovesupthevarioustechnicalaspectsofthesystem.Itwassuggestedthatasingleoverlyambitiousdemonstrationprojectthatfeaturesseveralinnovativetechnologiesincreasestheriskthatanyonenoncriticaltechnicalfailuremaybecomeinterpretedasafailureoftheoverallsystem.
ThegoalofPhaseIIIwillincludefulltestingoftheconvertersystem,includingthemanufacturerandthird‐partyfunctional,compliance,andperformancetestingneededtomovetheconvertertechnology
Page 478
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-8
fromadvancedprototypestoacommercialproduct.PhaseIIIwillalsoincludeafullscalefielddemonstrationoftheHVDCtechnologyonautilitysysteminAlaska.Thespecificprojectdetailsaredependantonthecandidatelocationselectedfortheintertie.PhaseIIIisintendedtobethefinalproof‐of‐conceptproject,tobefollowedbycommercialdeploymentofthesystem.
H.3 CRITERIAFORDEMONSTRATIONPROJECTSITES
PhaseIIIdemonstrationswillpresentafullyfunctionalreal‐worldHVDCtransmissionlineusingtheconvertertechnologydevelopedinthisproject.AvailableinventoriesofAlaskaintertiecandidatesarepresentedinDistributingAlaska’sPower(WHPacific,2008)andRuralAlaskaElectricUtilityIntertiesSurvey(Neubauer,1997).
Polarconsultconductedanextensivereviewofpotentialcandidatedemonstrationprojects,startingfromtheseresourcesandothercurrentinformation.Theresultinglistofpotentialdemonstrationprojectsisnotcomprehensive,astherearenumerousopportunitiesforruralAlaskapowerinterties,butitdoesprovidearepresentativeselectionofgeographicandtechnicalcriteriafordemonstrationsites.Threetypesofdemonstrationprojectswereconsidered,listedbelow.KeyfactorsaboutthesuitabilityofthesetypesofprojectsaresummarizedinTableH‐1.
1. NewRuralAlaskaHVDCIntertie.ThisoptionwouldbeafullyfunctionalHVDCintertiedemonstration.ItwouldconsistofbuildinganewintertiebetweentwoAlaskavillages,orpossiblybetweenalargergridandavillage.
2. NewACDistributionLineExtensionOperatedasHVDCforTrialPeriod.Thisoptionwouldbeanewalternatingcurrent(AC)distributionlineextensionfromanexistingsystemtoanewarea.ThelineextensionwouldbeoperatedasanHVDClineforthedemonstrationperiod,andthenconvertedtoACafterthedemonstrationprojectconcluded.
3. ExistingACDistributionLineExtension,ConvertedtoHVDCforDemonstrationThenSwitchedBacktoAC.ThisoptionwouldconvertanexistingACdistributionlinetoHVDCforthedemonstrationproject.ThelinewouldbeconvertedbacktoACafterthedemonstrationprojectconcluded.
Page 479
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-9
Table H-1 Types of HVDC Demonstration Projects and Factors for Each
Projects
Factors
Permanent HVDC Intertie Between Two Alaska
Villages
(Operate as HVDC)
AC Distribution System Extension
(Operate as HVDC, then convert to AC)
Existing AC Distribution Line
(Convert to HVDC, then revert to AC)
Function Intertie limited to power transmission (no services along intertie route)
Power Capacity
Peak load limited to 500 kW (to utilize existing prototype converters)
Cost & Length Intertie length of 10+ miles
to achieve cost savings over an AC intertie
Minimize intertie length (to maintain affordable budget and help avoid funding delays)
Schedule
3 to 5+ years
Requires (design, permitting, right-of-way,
funding, etc.)
1-3+ years
(May require right-of-way acquisition, design, permitting,
funding, etc.)
+/- 1 year
(Existing right-of-way, should require fewer permits and design,
funding, etc.)
Benefits
1. HVDC demonstration.
2. New intertie lowers utility costs to both communities.
1. HVDC demonstration.
2. Utility/public receive an AC line extension.
1. HVDC demonstration only. Hosting utility incurs costs and customers incur
service interruptions.
Organizational Complexity
Two utilities involved, may require RCA involvement and regulatory oversight.
Single utility involvement (to reduce interconnection or
regulatory issues).
Single utility involvement (to reduce interconnection or
regulatory issues).
Technical
Intertie connections at 480-V bus of existing
power plants.
Intertie connections at distribution voltage. Step
up/down transformers required.
Intertie connections at distribution voltage. Step
up/down transformers required.
kW:kilowatt
RCA:RegulatoryCommissionofAlaska
V:volt
Page 480
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-10
H.4 POTENTIALDEMONSTRATIONPROJECTS
H.4.1 SummaryofProjectsConsidered
TheintertiesprojectsreviewedbyPolarconsultarelistedbycategoryinTableH‐2andshownonFigureH‐1.Moredetailedinformationandpreliminarymapsofpotentialintertieroutesareprovidedonthefollowingpages.
Table H-2 Potential HVDC Demonstration Projects
RuralAlaskaMicrogrids MajorAlaskaGrids
New HVDC Intertie
Build as HVDC; keep as HVDC after demonstration.
Barrow – Atqasuk (NSB) Pilgrim Hot Springs – Nome (NJUS)St. Mary’s – Mountain Village – Pilot
Station (AVEC) Dillingham – Manokotak (NEC) New Stukahok – Ekwok (AVEC) Kodiak – Ouzinkie (KEA - OED)
Kake – Petersburg (IPEC/SEAPA)
Hoonah – Green’s Creek (IPEC/ AEL&P)
AC Line Extension
Build as HVDC; convert to AC after demonstration.
Gustavus – Glacier Bay Nat’l Park (GEC)
Delta Junction (GVEA) Deltana (GVEA)
Independence Mine (MEA)
Existing AC Line Demonstration
Convert to HVDC; revert to AC after demonstration.
Dillingham – Aleknagik (NEC) Glennallen – Eureka (CVEA) Canyon Creek – Hope (CEA)
Homer – Seldovia (HEA)
AcronymsandAbbreviations:
NEC NushagakElectricCooperative,Inc.
NSB NorthSlopeBorough
NJUS NomeJointUtilityService
IPEC InsidePassageElectricCooperative,Inc.
SEAPA SoutheastAlaskaPowerAgency
GEC GustavusElectricCompany
AVEC AlaskaVillageelectricCooperative,Inc.
CEA ChugachElectricAssociation,Inc.
HEA HomerElectricAssociation,Inc.
CVEA CopperValleyElectricAssociation,Inc.
KEA KodiakElectricAssociation,Inc.
OED CityofOuzinkieElectricDepartment
MEA MatanuskaElectricAssociation,Inc.
GVEA GoldenValleyElectricAssociation,Inc.
Page 481
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-11
Figure H-1 Location Map for Potential Demonstration Project Sites
Page 482
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-12
H.4.2 HVDCDemonstrationProjectsonExistingACDistributionLines
ThissectionprovidesoverviewsofpotentialHVDCdemonstrationprojectsthatwouldbeimplementedonexistingACdistributionlines.TheAClinewouldbeconvertedtoHVDCserviceforthedemonstrationproject,andaftertheHVDCdemonstrationiscompleted,thelinewouldberevertedtoACservice.Thecandidateintertiesareorganizedgeographically,movingfromnorthwesttosoutheast.
H.4.2.1 DillinghamtoAleknagikACLineConversion(DemonstrationOnly)
Thisisanexisting,approximately25‐mile‐long,three‐phaseACintertiethatprovideselectricservicetoAleknagikfromNushagakElectricCooperative’sdieselgeneratorsinDillingham(FigureH‐2).ThelineisunderstoodtobeofstandardRuralUtilitiesService(RUS)construction,insulatedto34.5kilovolts(kV)butoperatedasa7.2/12.4‐kVintertie.ThisexistinglinewouldbeconvertedtoHVDCoperationforademonstrationperiod,andthenrevertedtonormalACoperationafterthedemonstrationiscompleted.
TheloadinAleknagikisnotknown.Ifitexceeds500kilovolt‐amperes(kVA),theneitheradditionalintertiecapacityordieselgeneratorsinAleknagikwouldberequired.
Theexistinginsulatorsontheintertieshouldbesufficientforserviceat50kVDC.Becausethelineisinsulatedat34.5kV(approximatelyequalto60kVDC),theremaybeissueswithbuildupofcontaminationunderastaticDCelectricfieldleadingtoarcingovertheinsulators.Ifthisbecameanissue,theinsulatorswouldneedtobecleaned.AnalysisiswarrantedtoseeiftheHVDCintertievoltageshouldbereducedtoavoidthisproblem.VoltagereductionwouldalsodecreasethepowerthroughputcapabilityoftheHVDCconverters.
H.4.2.2 EurekaACLineConversion(DemonstrationOnly)
Thisisanexisting,approximately50‐mile‐long,single‐phase,14.4‐kVdistributionlineownedandoperatedbyCopperValleyElectricAssociation,Inc.(CVEA)servingthecommunitiesandresidentswestofGlennallen,Alaska(FigureH‐3).ThedemonstrationprojectwouldconsistofconvertingasegmentofthislinetoHVDCoperationforthedemonstrationperiod,thenconvertingitbacktoACoperation.
ThegeotechnicalconditionsalongthislinearebelievedtobefavorablefortestingaSWERconfigurationinpermafrostsoilsalthoughanappropriatelinesegmentwouldneedtobeidentifiedforSWERoperation.
ThepeakloadontheHVDCsegmentofthelinewoulddependonwherethedemonstrationwouldtakeplacealongtheline.Apeakloadof167kVAorlesswouldbepreferredtoallowuseofthe500‐kVAprototypeconverters.
PreliminarydiscussionswereheldwithCVEAinFebruary2011regardingthisdemonstrationproject.Aspecificsitewasnotidentified,butCVEAwasgenerallysupportiveofhostingtheHVDCdemonstrationproject,providedthatitdidnotdamageutilityassetsornegativelyimpactcustomersandwasrevenue‐neutraltotheutility(Botulinski,privateconversation,2011).
H.4.2.3 HopeSubstationtoHopeACLineConversion(DemonstrationOnly)
Thisisanexisting,approximately20‐mile‐long,singlephase,14.4‐kVdistributionlineownedandoperatedbyChugachElectricAssociation,Inc.(CEA)servingthecommunityofHopeonTurnagainArmnearAnchorage(FigureH‐4).Hopehasapeakloadofapproximately300kilowatts(kW).CEAisplanningamultipartupgradeofthislinetoaddressreliabilityissues.Thefirstpartofthisupgradeprojectwouldrebuildandrelocateapproximately4milesoftheintertiestartingattheHopeSubstationneartheHope
Page 483
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-13
JunctionontheSewardHighway.CEAestimatesthatthisprojectwouldbereadyforconstructionin2013(Jenkins,privateconversation,2011).Thedemonstrationprojectwouldcoordinatewiththelineupgrade.
Thedemonstrationprojectwouldrequiretransformersoneitherendofthedemonstrationsegmenttoconvertbetween14.4kVandthe480‐VACinterfaceofthepowerconverters.Inaddition,becausethe14.4‐kVlineissinglephase,theconvertercapacitywouldbereducedbyapproximately1/3to167kVA.ThiscouldbeaddressedeitherwithincreasedconvertercapacityoroccasionaloperationoftheexistingdieselgeneratorinHopetomeetpeakloads.
CEAissupportiveofhostingtheHVDCdemonstrationproject,providedthatitdidnotdamageutilityassetsornegativelyimpactcustomersandwasrevenue‐neutraltotheutility.Whilethisintertieappearstechnicallyfeasible,lesscomplicatedHVDCdemonstrationprojectslikelyexistwithinthestate.
H.4.2.4 Homer–SeldoviaACLineConversion(DemonstrationOnly)
ThisisanexistingdistributionlineownedandoperatedbyHomerElectricAssociation,Inc.(HEA),servingthecommunitiesonthesouthsideofKatchemakBayfromHalibutCovetoSeldovia.Thelineisthree‐phase,24.9‐kVACstartinginHomer.ItcrossesKatchemakBaywitha4.5‐mile‐longcableinstalledin2001,andthencontinuesasanoverheadlinetothesouthbaycommunities(FigureH‐5).TheoverheadlineisacombinationofconventionalRUSconstructionandtreecable.Loadonthisdistributioncircuitisapproximately1,100kVA(McDonough,privateconversation,2011).
TheconceptforthisdemonstrationprojectwouldbetooperatetheexistingsubmarinecableasanHVDCcableforthedemonstrationproject.Therearetwochallengeswiththisconcept:
1. Thepeakloadonthecircuitisapproximatelytwicethecapacityoftheprototypeconverters.ThiswillrequireloadsharingbetweenHEAthroughtheHVDClinkanddieselsonthesouthsideofthecable.Thisisnotatechnicalchallenge;however,itwillresultinsignificantcoststhatthedemonstrationprojectbudgetwouldneedtoabsorb.500kWofcontinuousdieselgenerationfora6‐monthdemonstrationperiodwouldcostapproximately$700,000.Abetteralternativeatthispricemaybetobuildtwomore500kWconvertermodules,increasingtheHVDCintertiecapacityto1,000kW.
2. Theexistingsubmarinecableisonlyratedfor24.9kVAC.Thisisapproximatelyequalto43kVDC,lessthanthenominalHVDCsystemvoltageof50kV.Twopossibleremediesexistforthis.IfHEAcanbeassuredthatthecablewilloperateat50kVDCwithoutilleffect,thenthedemonstrationprojectcouldproceed.GiventhatcablesaretypicallysubjectedtoDCvoltagesontheorderof50to100kVduringacceptancetests,itseemslikelythatthiswouldbepossible.Thenatureoftheseassuranceshasnotbeendefined.ThesecondremedyistodecreasetheoperatingvoltageoftheHVDCintertie.PPShasindicatedthattheconvertersoftwarecanbeprogrammedtoreducetheDCvoltage;however,thiswilldecreasethepowerratingoftheconverters.Loweringthevoltagefrom50to40kVwouldlowerthepowerratingofaconvertermodulefromapproximately500to400kVA.
HEAissupportiveofhostingtheHVDCdemonstrationproject,providedthatitdidnotdamageutilityassetsornegativelyimpactcustomersandwasrevenue‐neutraltotheutility.Whilethisintertieappearstechnicallyfeasible,lesscomplicatedHVDCdemonstrationprojectslikelyexistwithinthestate.
H.4.3 HVDCDemonstrationProjectsonNewACDistributionLineExtensions
ThissectionprovidesoverviewsofpotentialHVDCdemonstrationprojectsthatwouldbeimplementedonpurpose‐builtACdistributionlineextensions.AftertheHVDCdemonstrationiscompleted,thelinewouldbeconvertedtoACserviceandwouldbealastingbenefittotheutilityandnewlyservedcustomers.Thecandidateintertiesareorganizedgeographically,movingnorthwesttosoutheast.
Page 484
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-14
H.4.3.1 GVEAPhillipsRoadLineExtension
Thisprojectwouldbeanapproximately1.75‐milesingle‐phaseoverheaddistributionextensiontoserveseveralresidencesattheendofPhillipsRoadinDeltaJunction,withintheGoldenValleyElectricAssociation,Inc.(GVEA)servicearea(FigureH‐6).ThelineextensionwouldbebuiltasastandardACdistributionline,operatedasanHVDCintertiefordemonstrationpurposes,andthenturnedovertoGVEAforsubsequentoperationasanACdistributionline.
GVEAandtheresidencesattheendofthelinewouldbothlikelycontributefundsorin‐kindservicestothelineextension.Totalcontributionisestimatedat$50,000,andthelinebuild,excludinganycostsassociatedwiththeHVDCdemonstration,isbudgetedat$140,000.Aright‐of‐waywouldneedtobeobtainedfortheproject,whichwouldtakeanestimated6to12months.
TheprojectislocatedincloseproximitytotheTrans‐AlaskaPipelineSystem,andassuchwouldlikelynotbesuitablefordemonstrationofSWERoperation.Thepeakloadoftheresidencesattheendofthelineislikelylessthantheapproximately167‐kVAcapacityofthe500‐kWprototypeconvertersinsingle‐phaseoperation.
GVEAisverysupportiveofhostingtheHVDCdemonstrationproject,providedthatitdidnotdamageutilityassetsornegativelyimpactcustomersandwasrevenue‐neutraltotheutility,beyondthein‐kindconstructioncontributionsthatGVEAofferedforthelineextension(Wright,privateconversation,2011).
H.4.3.2 GVEACummingsRoadLineExtension
Thisprojectwouldbeanapproximately4‐to6‐milesingle‐phaseoverheaddistributionextensiontoserveseveralresidencesattheendofCummingsRoadinDeltana,withintheGVEAservicearea(FigureH‐7).ThelineextensionwouldbebuiltasastandardACdistributionline,operatedasanHVDCintertiefordemonstrationpurposes,andthenturnedovertoGVEAforsubsequentoperationasanACdistributionline.
GVEAandtheresidencesattheendofthelinewouldbothlikelycontributefundsorin‐kindservicestothelineextension.Totalcontributionisestimatedat$60,000,andthelinebuild,excludinganycostsassociatedwiththeHVDCdemonstration,isbudgetedat$560,000.Aright‐of‐waywouldneedtobeobtainedfortheproject,whichwouldtakeanestimated6to12months.
Thepeakloadoftheresidencesattheendofthelineislikelylessthantheapproximately167‐kVAcapacityofthe500‐kWprototypeconvertersinsingle‐phaseoperation.
GVEAisverysupportiveofhostingtheHVDCdemonstrationproject,providedthatitdidnotdamageutilityassetsornegativelyimpactcustomersandwasrevenue‐neutraltotheutility,beyondthein‐kindconstructioncontributionsthatGVEAofferedforthelineextension(Wright,2011).
H.4.3.3 MEAtoIndependenceMineLineExtension
Thisprojectwouldbeanapproximately5.5‐mileundergroundACdistributionlinefromtheendofMatanuskaElectricAssociation,Inc.(MEA)’sexistingHatcherPassdistributionlineuptotheIndependenceMineStateHistoricalPark(StatePark)(FigureH‐8).ThelinewouldbebuiltasanACdistributionfeeder,operatedasanHVDClineforthedemonstrationproject,andthenrevertedtoACoperation.
Page 485
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-15
Easementsforthefirstapproximately2milesofthelineextensionarependingfromtheAlaskaDepartmentofNaturalResources(ADNR)andMatanuska‐SusitnaBorough(MSB)foraproposedhydroelectricprojectlocatedalongtheroute.42Neweasementswouldberequiredfortheremainingapproximately3.5milestotheStatePark.TheintertiewouldeliminatetheneedfordieselgenerationattheStateParkduringthesummermonths.ThehydroelectricprojectdeveloperandADNRDivisionofParksandRecreationbothmaysupportthisprojectwithmatchingfunds.
Whencontactedregardingthisproject,theStateParkwassupportive(Biessel,privateconversation,2011).Threeprivateentitieslocatedneartheparkexpressednointerestinconnectingtotheline.Whencontactedregardingthisproject,MEAexpressedconcernsaboutitsstaffavailabilitytosupportthisproject(Kuhn,privateconversation,2011).
H.4.4 HVDCIntertieProjects
ThissectionprovidesoverviewsofpotentialHVDCintertiesbetweenruralAlaskacommunities.Theintertiesareorganizedgeographically,startinginthenorthwestandmovingtothesoutheast.
H.4.4.1 BarrowtoAtqasukHVDCIntertie
This75‐mile‐longoverlandintertiewouldconnectAtqasuk,whichuseshigh‐costdieselforelectricity,toBarrow,whichgenerateselectricityfromlow‐costnaturalgas(FigureH‐9).ThisprojectcouldincludeconversionofAtqasuktoelectricheatingtoachievegreaterbenefits.TheNorthSlopeBoroughiscurrentlystudyingthisintertie.IftheHVDCtechnologyiscommerciallyavailableinatimelymanner,itcouldbeusedonthisintertie.Ifitisnot,theintertiewouldbebuiltasathree‐phaseACline.
H.4.4.2 NometoTellerandBrevigMissionHVDCIntertie
Thisapproximately75‐mile‐longoverlandintertiewouldconnectTellerandBrevigMission—whichbothgenerateelectricitywithdieselfuel—toNome,whichgenerateselectricityfromdieselandsomewind(FigureH‐10).TheAlaskaVillageElectricCooperative,Inc.(AVEC)recentlybuiltanintertiebetweenTellerandBrevigMission.IfthePilgrimHotSpringsgeothermalresourceisdevelopedandislargeenoughtosupplyNomeaswellasTellerandBrevigMission,itcouldsignificantlyreduceelectriccostsinthesevillages.
H.4.4.3 PilgrimHotSpringstoNomeHVDCIntertie
ThegeothermalresourceatPilgrimHotSpringscouldprovideelectricityforNome.Oneofthechallengeswiththisrenewableenergyconceptisthecostoftheapproximately60‐miletransmissionlinebetweenPilgrimHotSpringsandNome(FigureH‐10).UsingthisHVDCtechnologycouldreducethecostsofthisintertie,improvingprojecteconomics.OnepotentialhurdleforthisdemonstrationprojectcandidateisthatthePilgrimHotSpringsresourcehasbeententativelyestimatedat5megawatts(MW).Thisislargerthanthecapacityoftheprototypeconverters,andapproximatelyten500‐kWconverterswouldbeneededateachendoftheintertie.PPShasindicatedthatparallelingthismanyconverterstogetheristechnicallyfeasiblebutthisfunctionhasnotbeenverifiedatthistime.ACEPisassessingthegeothermalresourceatPilgrimHotSprings,whichwillhelpdeterminehowmuchpowercanbederivedfromtheresource(Mager,privateconversation,2011).
42ThedeveloperofthishydroelectricprojectisanaffiliatedinterestofPolarconsultAlaska,Inc.
Page 486
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-16
H.4.4.4 St.Michaels–StebbinsHVDCIntertie
Thisapproximately10‐mile‐longoverlandintertiewouldconnectSt.MichaelsandStebbins,twovillagesservedbytheAVEC,allowingAVECtoeconomizebyconsolidatingbulkfuelandgenerationassetsandoperationsatonevillage(FigureH‐11).Thereisgoodmarineaccesstobothvillages.TherelativelyshortdistanceofthisintertiereducesthesavingsofanHVDCintertiecomparedwithanACintertie.
H.4.4.5 St.Mary’stoMountainVillageHVDCIntertie
Thisapproximately26‐mile‐longoverlandintertiewouldconnectSt.Mary’sandMountainVillageontheYukonRiver,allowingAVECtoeconomizebyconsolidatingbulkfuelandgenerationassetsandoperationsatonevillage(FigureH‐12).Thereisgoodaccesstobothvillages,andanexistingroadbetweenthemwouldfacilitateconstructionoftheoverheadintertie.
H.4.4.6 DillinghamtoManokotakHVDCIntertie
Thisapproximately20‐mile‐longintertiewouldconnectManokotaktoDillingham(FigureH‐2).ThisintertiewouldallowtheDillinghamandManokotakelectricutilitiestoconsolidateoperations,loweringcostsinManokotak,andimprovingtheeconomiesofscaleforbothutilities.Inaddition,Dillinghamiscurrentlystudyingtwohydroelectricresources,LakeGrantandLakeElva,whichwouldprovidestable,low‐costelectricity.Iftheseprojectsarebuilt,ratesinManokotakwouldbesignificantlyreducedwiththisintertie.AnintertiebetweenManokotakandDillinghamhasbeenstudiedinthepast(Polarconsult,1986)buthasnotbeenconstructed.TheproposedHVDCtechnologycouldreducecostsfortheintertie,improvingprojecteconomics.
H.4.4.7 NewStuyahok–EkwokHVDCIntertie
Thisapproximately8‐mileoverlandintertiewouldconnectthesetwoAVECvillages,allowingAVECtoeconomizebyconsolidatingbulkfuelandgenerationassetsandoperationsatonevillage(FigureH‐13).TherelativelyshortdistanceofthisintertiereducesthesavingsofanHVDCintertiecomparedwithaconventionalACintertie.
H.4.4.8 Kodiak–OuzinkieHVDCIntertie
Thisapproximately8‐mile‐longsubmarinecableintertiewouldconnectOuzinkiewiththeKodiakElectricAssociation,Inc.(KEA)grid(FigureH‐14).Ouzinkiegenerateselectricitywithacombinationofhydroanddiesel.KEAgenerateselectricityfromacombinationofhydro,wind,anddiesel.DuetothedifferentgenerationsourcesandeconomyofscaleontheKEAsystem,KEA’selectricratesaresignificantlylowerthanOuzinkie’s.TheintertiewouldbenefitKEAbyincreasingloadandwouldbenefitOuzinkiebyreducingrates.KEAandOuzinkiehavealreadystudiedanoverlandintertiewithashortACcablecrossingofNarrowStrait(Dryden&Larue,2011).Theestimatedcostsoftheshortcablecrossingareasignificantportionofthetotalprojectcost,inpartduetothemobilizationcostsofspecializedequipmentforcableinstallation.Itmaybemorecost‐effectivetoinstallasubmarineHVDCcablefortheentireroute.
ThisintertieappearstobeasuitablecandidateforanHVDCdemonstrationproject.TheeconomicbenefitstoOuzinkieappeartobesignificant(Totemoff,privateconversation,2011).AsubmarineHVDCcableusingthetechnologydevelopedinthisprojectappearstobealessexpensiveoptionthantheoverhead/cablecrossingoption.Ouzinkie’speakloadisapproximately400kW,withinthecapacityoftheprototypeconverters.Furtherconversationswiththeprojectstakeholdersarewarranted.
Page 487
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-17
H.4.4.9 Green’sCreektoHoonahHVDCIntertie
This26‐mile‐longsubmarineintertiewouldconnectHoonahtoAlaskaElectricLightandPowerCompany(AEL&P)’sJuneaupowergrid,providinglower‐costpowertoHoonah(FigureH‐15).TheintertieisagoodlengthforHVDCandwouldprovideaclearbenefittoHoonah.Theintertiehasbeenunderconsiderationforseveralyears,andsignificantengineeringstudieshavealreadybeencompleted.TheintertieisuneconomicusingACtransmissionorexistingHVDCtechnology.TheproposedHVDCtechnologycouldreducecostsfortheintertie,improvingprojecteconomics.
H.4.4.10 PetersburgtoKakeHVDCIntertie
Thisapproximately60‐mile‐longsubmarineandoverlandintertiewouldconnectKakewiththePetersburg‐Ketchikangrid(FigureH‐16).TheintertiewouldallowKaketoconvertfromhigh‐costdieselelectricitytolow‐costhydroelectricity,andwouldbepartoftheproposedsoutheastintertiegrid.UsingHVDCcouldreducecostsbyallowinglongerspans,buriedcable,orincreaseduseofsubmarinecable.Whilea1‐MWmonopolarHVDCintertiewouldbesufficienttoserveKake,futureextensionofthesoutheastintertietoSitkaordevelopmentofnearbyhydropowerresourcescouldincreasetheloadonthisintertietotensofmegawatts.
H.4.4.11 GustavustoGlacierBayNationalParkIntertie(HVDCDemonstrationOnly)
Withthecompletionofthe800‐kWFallsCreekHydroelectricProjectin2009,Gustavusnowhasexcesshydropower.TheheadquartersofGlacierBayNationalPark,locatedapproximately5to10milesfromGustavus,continuestorelyondieselgenerationforelectricity(FigureH‐15).ConnectingtheparkheadquarterswithGustavuswouldallowtheParktoreducefuelconsumptionandoperatingcostsandwouldallowGustavustoincreaseitsratebaseandpowersales,loweringoverallrates.AburiedHVDCcablewouldbepreferabletooverheadAClinesinthepark,whereaestheticsareamajorfactor.Duetotherelativelyshortlength,anHVDCintertiemaynotbecost‐effectivecomparedtoanACintertie.
Page 488
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-18
H.4.5 ProjectMaps
Figure H-2 Vicinity Map for Demonstration Projects near Dillingham
Page 489
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-19
Figure H-3 Vicinity Map for Eureka AC Line Conversion
Page 490
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-20
Figure H-4 Vicinity Map for Hope AC Line Conversion
Page 491
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-21
Figure H-5 Vicinity Map for Seldovia AC Line Conversion
Page 492
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-22
Figure H-6 Vicinity Map for Delta Junction AC Line Extension
Page 493
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-23
Figure H-7 Vicinity Map for Deltana AC Line Extension
Page 494
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-24
Figure H-8 Vicinity Map for Independence Mine AC Line Extension
Page 495
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-25
Figure H-9 Vicinity Map for Barrow – Atqasuk HVDC Intertie
Page 496
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-26
Figure H-10 Vicinity Map for Demonstration Projects near Nome
Page 497
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-27
Figure H-11 Vicinity Map for St. Michaels – Stebbins HVDC Intertie
Page 498
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-28
Figure H-12 Vicinity Map for St. Mary’s – Mountain Village HVDC Intertie
Page 499
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-29
Figure H-13 Vicinity Map for New Stuyahok – Ekwok HVDC Intertie
Page 500
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-30
Figure H-14 Vicinity Map for Kodiak – Ouzinkie HVDC Intertie
Page 501
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-31
Figure H-15 Vicinity Map for Gustavus and Hoonah HVDC Interties
Figure H-16 Vicinity Map for Kake – Petersburg HVDC Intertie
Page 502
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MAY 2012 PAGE H-32
Thispageintentionallyblank.
Page 503
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-1
APPENDIXI
STAKEHOLDERADVISORYGROUPINVOLVEMENTANDMEETINGS
Page 504
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-2
Thispageintentionallyblank.
Page 505
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-3
TABLEOFCONTENTS
I.1 INTRODUCTION........................................................................................................................................................7
I.2 LISTOFSAGMEMBERS.........................................................................................................................................8
I.3 SUMMARYOFSAGROLEANDPOLICIES.......................................................................................................9 I.3.1 POLICIESANDPROCEDURES............................................................................................................................................9
I.3.1.1 Formation......................................................................................................................................................9 I.3.1.2 ScheduledMeetings...................................................................................................................................9 I.3.1.3 Organization.................................................................................................................................................9 I.3.1.4 Communication...........................................................................................................................................9 I.3.1.5 Termination................................................................................................................................................11
I.4 STAKEHOLDERADVISORYGROUP(SAG)MEETINGPRESENTATIONMATERIALS.................12 I.4.1 SAGMEETING#1–FAIRBANKS,ALASKA(APRIL27,2010)................................................................................12 I.4.2 SAGMEETING#2–ANCHORAGE,ALASKA(JANUARY14,2011)........................................................................32 I.4.3 SAGMEETING#3–ANCHORAGE,ALASKA(OCTOBER25,2011).......................................................................53
I.5 HANDOUTSFROMOTHERMEETINGSCONDUCTEDDURINGTHEPROJECT...........................105 I.5.1 SOUTHEASTCONFERENCEMID‐SESSIONSUMMIT–JUNEAU,ALASKA(MARCH2,2010)............................107 I.5.2 EMERGINGENERGYTECHNOLOGYFORUM–JUNEAU,ALASKA(FEBRUARY14,2011).................................113 I.5.3 BROWN‐BAGWORKSESSION–ANCHORAGE,ALASKA(AUGUST29,2011)...................................................125 I.5.4 HVDCCONVERTERDEMONSTRATION–LAWRENCEVILLE,NEWJERSEY(NOVEMBER14,2011).............145
I.6 ADDITIONALMEETINGS.................................................................................................................................151
Page 506
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-4
Thispageintentionallyblank.
Page 507
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-5
LISTOFTABLES
TableI‐1 ListofSAGMembers.................................................................................................................................8
TableI‐2 SummaryofCorrespondencewithSAGMembers......................................................................10
Page 508
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-6
Thispageintentionallyblank.
Page 509
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-7
I.1 INTRODUCTION
ThisappendixprovidesthefollowingdetailedinformationregardingtheStakeholdersAdvisoryGroup(SAG)formedforPhaseIIoftheHigh‐VoltageDirectCurrent(HVDC)DevelopmentProgram:
● ListofSAGmembers;
● SummaryofSAGroleandpolicies;
● SummaryofkeyinformalcorrespondencebetweenSAGmembersandPolarconsultoverthecourseoftheproject;
● HandoutsandtranscriptsfromthethreeSAGmeetings;and
● Handoutsfromothermeetingsandoutreachactivitiesconductedoverthecourseoftheproject.
Meetingtranscriptsareavailableseparately.
Page 510
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-8
I.2 LISTOFSAGMEMBERS
Table I-1 List of SAG Members
Company First Name Last Name Position
Denali Commission Denali Daniels SAG Chair Alaska Center for Energy and Power (ACEP) Gwen Holdmann ACEP Director Alaska Center for Energy and Power (ACEP) Jason Meyer ACEP Project Manager Alaska Center for Energy and Power (ACEP) Brent Sheets SAG Member Polarconsult Alaska, Inc. Joel Groves Project Manager Polarconsult Alaska, Inc. Earle Ausman President Polarconsult Alaska, Inc. David Ausman Vice President Princeton Power Systems, Inc. (PPS) Darren Hammell Executive Vice President Alaska Department of Labor (AKDOL) Daniel Greiner Alt. SAG Member Alaska Department of Labor (AKDOL) Alvin Nagel SAG Member Alaska Division of Community and Regional Affairs (DCRA) Percy Frisby SAG Member Alaska Energy Authority (AEA) David Lockhard SAG Member Alaska Power & Telephone Company (APT) Bob Grimm SAG Member Alaska Power Association (APA) Marilyn Leland SAG Member Alaska Village Electric Cooperative, Inc. (AVEC) Meera Kohler SAG Member Alaska Village Electric Cooperative, Inc. (AVEC) Brent Petrie Alt. SAG Member Bering Straits Native Corporation (BSNC) Jerald Brown SAG Member Bethel Electric Utility (BEC) Bob Charles SAG Member Copper Valley Electric Association (CVEA) Robert Wilkinson SAG Member Dillingham Nels Andersen SAG Member Golden Valley Electric Association, Inc. (GVEA) Brian Newton SAG Member Homer Electric Association, Inc. (HEA) Brad Janorschke SAG Member Inside Passage Electric Cooperative (IPEC) Jodi Mitchell SAG Member Institute of Northern Engineering (INE, UAF) Ron Johnson SAG Member Kodiak Electric Association, Inc. (KEA) Darron Scott SAG Member Kotzebue Electric Association, Inc. (KoEA) Brad Reeve SAG Member Matanuska Electric Association (MEA) Joe Griffith SAG Member Matanuska Electric Association (MEA) Trivia Singaraju Alt. SAG Member Naknek Electric Association, Inc. (NEA) Donna Vukich SAG Member Nat’l. Rural Electric Cooperative Association (NRECA) Tom Lovas SAG Member Nome Chamber of Commerce (NCC) Mitch Erickson SAG Member Nome Joint Utilities (NJUS) John Handeland SAG Member North Slope Borough (NSB) Kent Grinage SAG Member Northwest Arctic Borough (NWAB) Ingemar Mathiasson SAG Member Nushagak Electric Association Mike Favors SAG Member Nuvista Light and Power, Inc. (NLP) Bob Charles SAG Member Southeast Conference (SEC) Robert Venables Alt. SAG Member Southeast Conference (SEC) Shelly Wright SAG Member Southwest Alaska Municipal Conference (SWAMC) Andy Varner SAG Member U.S. Department of Agriculture (USDA) Rural Utilities Service (RUS) Eric Marchegiani SAG Member University of Alaska Fairbanks (UAF) Richard Wies SAG Member
Page 511
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-9
I.3 SUMMARYOFSAGROLEANDPOLICIES
I.3.1 PoliciesandProcedures
TheSAGisanadvisorybodycomprisedofrepresentativesofAlaska’sruralelectricutilityindustryandrelatedprofessionals.ThepurposeoftheSAGistoprovidecomments,feedback,review,andrecommendationstotheHVDCDevelopmentProgram,awardedbytheDenaliCommission(Commission),managedbytheAlaskaCenterforEnergyandPower(ACEP),andcontractedtoPolarconsultAlaska,Inc.(Polarconsult).
I.3.1.1 Formation
TomaintainindependenceoftheSAG,ACEPidentifiedmembersforparticipation,withconsiderationofrecommendationsfromPolarconsultandtheDenaliCommission.AfinalcandidatelistwassentoutforcommenttoPolarconsultandforwardedforapprovaltotheDenaliCommission.
I.3.1.2 ScheduledMeetings
PerthescopeofworkunderUAF–PolarconsultContract#10‐0055,theSAGformallyconvenedthreetimesoverthecourseoftheHVDCProject.Perthescopeofworkandbudget,thecostofconveningthesemeetingswastheresponsibilityofPolarconsult.Fundingformembertravelandparticipationcostswasnotprovided.Themeetingswereconvenedinamannerconducivetoremoteparticipationofmembers.ThemeetingdateswereApril28,2010;December1,2010;andJuly15,2011.
TheagendaforthesemeetingswassetbyACEP,withinputfromPolarconsultandtheDenaliCommissionandfinalapprovalbytheDenaliCommission.
I.3.1.3 Organization
TheSAGshallconsistoftheChair(theDenaliCommission)andmembers.TomaintainequalityontheSAG,individualorganizationsmayholdonlyonememberposition.Upto30SAGmemberswillbeallowed,thefinalnumberdeterminedbasedonthelevelofinterest.Ifatanytimeoverthecourseoftheprojectoneofthemembersresignsorisnolongeractive,ACEPwillinviteanotherindividualtofillthisposition,withtheapprovaloftheDenaliCommission.Membersmaydesignateproxiesfromwithintheirorganizationtoattendmeetings.
ACEPencouragesorganizationsandindividualsnotselectedfortheSAGtoparticipateinformallyinthisproject.Publiccommentisalwayswelcomeandane‐maillistandforumwillbemadeavailableontheACEPprojectwebsite.
I.3.1.4 Communication
Atcertainprojectmilestones,oruponrecommendationfromACEP,Polarconsultshallsolicitcomments,review,andrecommendationstotheHVDCprogram.AllformalcommunicationbetweenPolarconsultandtheSAGshallbethroughtheChair,withinclusionofACEP.PolarconsultisfreetocontactthewholeSAGformallyorcontactindividualSAGmembersinformally,astheneedarises.AllinformalcommunicationwillnotrepresenttheadviceorrecommendationsoftheSAG.Intheinterestsofpromotingmaximumfeedbackfromtheindustry,confidentialcommunicationswillbeacceptedwherethereisademonstratedneedtomaintainconfidentiality.
TableI‐2providesasummaryofcorrespondencewithSAGmembersrelatedtothisproject.
Page 512
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-10
Table I-2 Summary of Correspondence with SAG Members
Date SAG Member Participants Subject Summary
Jan.–Feb. 2010 MEA
Trivi Singaraju (MEA) Gary Kuhn (MEA)
Joel Groves (Polarconsult)
Demonstration Project Sites
Discussing potential HVDC demonstration project sites.
Jan.–Feb. 2010 CVEA Chris Botulinski (CVEA)
Earle Ausman (Polarconsult) Demonstration Project Sites
Discussing potential HVDC demonstration project sites.
Jan.–March 2010
At Large Citizen
Nels Anderson Earle Ausman (Polarconsult)
Demonstration Project Sites
Discussing potential HVDC demonstration project sites.
Jan.–March 2010 CEA
Ed Jenkin (CEA) Dave Ausman (Polarconsult) Joel Groves (Polarconsult)
Earle Ausman (Polarconsult)
Demonstration Project Sites
Discussing potential HVDC demonstration project sites.
Jan.–March 2010 HEA
Brad Zubeck (HEA) Kathy McDonough (HEA) Joel Groves (Polarconsult)
Demonstration Project Sites
Discussing potential HVDC demonstration project sites.
May–June 2010 NWAB Ingemar Mathiasson (NWAB)
Earle Ausman (Polarconsult)
International examples of
electric codes
Mr. Mathiasson used his contacts in Sweden to request examples of international electric codes with
regard to SWER circuits, HVDC, and related rural electric issues.
July–October
2010 AVEC
Brent Petrie (AVEC) Bill Thomson (AVEC) Mark Tietzel (AVEC)
Joel Groves (Polarconsult) Earle Ausman (Polarconsult)
HVDC Converter Specification
Discussions and comments from AVEC on draft specification for
HVDC power converter.
July–October
2010 UAF/ACEP
Richard Wies (UAF) Jason Meyer (ACEP)
Joel Groves (Polarconsult) Earle Ausman (Polarconsult)
HVDC Converter Specification
Discussions and comments from AVEC on draft specification for
HVDC power converter.
August 2010 AVEC Mark Teitzel (AVEC) Joel Groves (Polarconsult)
Conceptual Design of
Overhead Line
Request for examples of environmental loadings used on
previous AVEC interties, performance of these projects.
September 2010 IPEC Peter Bibb (IPEC)
Joel Groves (Polarconsult) Demonstration Project Sites
Discussing potential HVDC demonstration project sites.
October–November
2010 GVEA
Mike Wright (GVEA) Searl Burnett (GVEA)
Earle Ausman (Polarconsult)
Conceptual Design of
Overhead Line
Site visit to review design, performance, and failure modes of
guyed Y and X towers on transmission lines between
Fairbanks and Healy.
November 2010 AVEC
Brent Petrie (AVEC) Joel Groves (Polarconsult)
Earle Ausman (Polarconsult)
Demonstration Project Sites
Discussing potential HVDC demonstration project sites.
December 2010 SEC
Shelly Wright (SEC) Robert Venables (SEC)
Joel Groves (Polarconsult) Earle Ausman (Polarconsult)
Demonstration Project Sites
Discussing potential HVDC demonstration project sites.
January 2011 APT
Bob Grimm (APT) Earle Ausman (Polarconsult) Joel Groves (Polarconsult)
Demonstration Project Sites
Discussing potential HVDC demonstration project sites.
Page 513
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-11
Date SAG Member Participants Subject Summary
January 2011 NWAB
Ingemar Mathiasson (NWAB) Brent Petrie (AVEC)
Joel Groves (Polarconsult)
Demonstration Project Sites
Discussing potential HVDC demonstration project sites.
January 2011 RUS Eric Marchegiani (RUS)
Joel Groves (Polarconsult) Demonstration Project Sites
Discussing potential HVDC demonstration project sites.
January 2011 Multiple Multiple SAG Members Demonstration
Project Sites
Teleconference with SAG members on HVDC demonstration project
sites.
January–March 2011 GVEA
Mike Wright (GVEA) Joel Groves (Polarconsult)
Earle Ausman (Polarconsult)
Demonstration Project Sites
Discussing potential HVDC demonstration project sites.
March 2011 AVEC
Bill Thomson (AVEC) Joel Groves (Polarconsult)
Earle Ausman (Polarconsult) Randy Wachal (MHRC)
HVDC Controls and integration
Discussions among Polarconsult, Manitoba, and AVEC on system controls and integration needs.
May–June 2011 CVEA
Chris Botulinski (CVEA) Earle Ausman (Polarconsult) Joel Groves (Polarconsult)
HVDC Test Site Discussions looking for a test site for HVDC pole and foundations.
June 2011 UAF
Richard Wies (UAF) Jason Meyer (ACEP)
Joel Groves (Polarconsult) Earle Ausman (Polarconsult)
Examples of cold regions design for overhead HVDC
Visit of Chinese delegation regarding design of HVDC line across the
Tibetan Plateau.
June–July 2011 GVEA
Mike Wright (GVEA) Joel Groves (Polarconsult)
Earle Ausman (Polarconsult) HVDC Test Site Discussions looking for a test site for
HVDC pole and foundations
July 2011 AKDOL
Al Nagel (AKDOL) Dave Greiner (AKDOL) Randy Wachal (MHRC)
Joel Groves (Polarconsult)
SWER circuit safety.
Discussions with Alaska Department of Labor regarding HVDC SWER
circuits and soliciting comments on the SWER analysis prepared by
Manitoba.
November 2011 AVEC Pam Lyons (AVEC)
Joel Groves (Polarconsult) Converter
Shipping Cost
AVEC assistance on obtaining shipping costs to move prototype
converters to Alaska.
Nov, 2011 – Jan 2012 AVEC
Meera Kohler (AVEC) Mark Tietzel (AVEC) Brent Petrie (AVEC)
Joel Groves (Polarconsult)
Cost data for past AC projects
Discussions from November 2011 through January 2012 regarding details of cost data for remote
Alaska AC intertie projects built over the past decade.
December 2011 AKDOL
Al Nagel (AKDOL), Dave Greiner (AKDOL), Jason
Meyer (ACEP), Joel Groves (Polarconsult)
SWER circuit safety.
Discussions with Alaska Department of Labor regarding HVDC SWER
circuits and NESC code.
I.3.1.5 Termination
TheSAGshallbeformallyterminatedupontheendoftheprojectissuedfromtheDenaliCommission.
Page 514
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-12
I.4 STAKEHOLDERADVISORYGROUP(SAG)MEETINGPRESENTATIONMATERIALS
I.4.1 SagMeeting#1–Fairbanks,Alaska(April27,2010)
Page 515
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-13
Page 516
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-14
Page 517
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-15
Page 518
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-16
Page 519
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-17
Page 520
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-18
Page 521
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-19
Page 522
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-20
Page 523
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-21
Page 524
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-22
Page 525
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-23
Page 526
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-24
Page 527
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-25
Page 528
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-26
Page 529
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-27
Page 530
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-28
Page 531
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-29
Page 532
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-30
Page 533
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-31
Thispageintentionallyblank.
Page 534
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-32
I.4.2 SAGMeeting#2–Anchorage,Alaska(January14,2011)
Page 535
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-33
Thispageintentionallyblank.
Page 536
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-34
Page 537
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-35
Page 538
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-36
Page 539
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-37
Page 540
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-38
Page 541
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-39
Page 542
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-40
Page 543
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-41
Page 544
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-42
Page 545
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-43
Page 546
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-44
Page 547
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-45
Page 548
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-46
Page 549
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-47
Page 550
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-48
Page 551
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-49
Page 552
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-50
Page 553
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-51
Page 554
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-52
Thispageintentionallyblank.
Page 555
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-53
I.4.3 SAGMeeting#3–Anchorage,Alaska(October25,2011)
Page 556
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-54
Thispageintentionallyblank.
Page 557
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-55
Page 558
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-56
Page 559
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-57
Page 560
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-58
Page 561
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-59
Page 562
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-60
Page 563
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-61
Page 564
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-62
Page 565
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-63
Page 566
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-64
Page 567
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-65
Page 568
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-66
Page 569
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-67
Page 570
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-68
Page 571
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-69
Page 572
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-70
Page 573
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-71
Page 574
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-72
Page 575
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-73
Page 576
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-74
Page 577
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-75
Page 578
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-76
Page 579
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-77
Page 580
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-78
Page 581
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-79
Page 582
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-80
Page 583
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-81
Page 584
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-82
Page 585
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-83
Page 586
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-84
Page 587
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-85
Page 588
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-86
Page 589
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-87
Page 590
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-88
Page 591
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-89
Page 592
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-90
Page 593
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-91
Page 594
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-92
Page 595
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-93
Page 596
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-94
Page 597
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-95
Page 598
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-96
Page 599
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-97
Page 600
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-98
Page 601
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-99
Page 602
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-100
Page 603
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-101
Page 604
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-102
Page 605
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-103
Page 606
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-104
Page 607
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-105
I.5 HANDOUTSFROMOTHERMEETINGSCONDUCTEDDURINGTHEPROJECT
Page 608
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-106
Thispageintentionallyblank.
Page 609
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-107
I.5.1 SoutheastConferenceMid‐SessionSummit–Juneau,Alaska(March2,2010)
Page 610
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-108
Thispageintentionallyblank.
Page 611
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-109
Page 612
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-110
Page 613
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-111
Page 614
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-112
Page 615
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-113
I.5.2 EmergingEnergyTechnologyForum–Juneau,Alaska(February14,2011)
Page 616
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-114
Thispageintentionallyblank.
Page 617
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-115
Page 618
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-116
Page 619
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-117
Page 620
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-118
Page 621
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-119
Page 622
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-120
Page 623
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-121
Page 624
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-122
Page 625
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-123
Page 626
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-124
Page 627
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-125
I.5.3 Brown‐BagWorkSession–Anchorage,Alaska(August29,2011)
Page 628
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-126
Thispageintentionallyblank.
Page 629
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-127
Page 630
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-128
Page 631
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-129
Page 632
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-130
Page 633
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-131
Page 634
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-132
Page 635
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-133
Page 636
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-134
Page 637
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-135
Page 638
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-136
Page 639
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-137
Page 640
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-138
Page 641
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-139
Page 642
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-140
Page 643
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-141
Page 644
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-142
Page 645
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-143
Page 646
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-144
Page 647
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-145
I.5.4 HVDCConverterDemonstration–Lawrenceville,NewJersey(November14,2011)
Page 648
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-146
Thispageintentionallyblank.
Page 649
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-147
Page 650
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-148
Page 651
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-149
Page 652
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-150
Thispageintentionallyblank.
Page 653
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-151
I.6 ADDITIONALMEETINGS
Page 654
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-152
Thispageintentionallyblank.
Page 655
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-153
ThefollowingadditionalmeetingswereheldduringthecourseofthisprojectregardingaHVDCtransmissionsysteminruralAlaska.
● SoutheastConferenceMid‐SessionSummit–Juneau,Alaska(MARCH2,2010)
● EmergingEnergyTechnologyForum–Juneau,Alaska(February14,2011)
● Brown‐BagWorkSession–Anchorage,Alaska(August29,2011)
Page 656
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE I-154
Thispageintentionallyblank.
Page 657
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE J-1
APPENDIXJ
BIBLIOGRAPHY
Page 658
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE J-2
Thispageintentionallyblank.
Page 659
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE J-3
AlaskaCenterforEnergyandPower(ACEP,2012).AlaskaStrandedRenewables.APreliminaryFrameworkforAssessment.December2011.
AlaskaEnergyAuthority(AEA,2007).FY2008CapitalProjectSummarySheet,Napakiak‐BethelIntertieRightofWayandSiteControlProject.April19,2007.
AlaskaEnergyAuthority(AEA,2010a).DataExportfromthePowerCostEqualizationProgramDatabase.2010.
AlaskaEnergyAuthority(AEA,2010b).AlaskaEnergyPathwaytowardEnergyIndependence.DraftRelease.April2010.
AlaskaJournalofCommerce(AJOC,2001).“NewKatchemakBayCableQuadruplesEnergyPossibilities.:November26,2001.
AlaskaVillageElectricCooperative,Inc.(AVEC,2008).ApplicationforRenewableEnergyFundGrant,Emmonak,Alaska,WindDesignandConstructionProject.November11,2008.
Arrillaga,Josu(Arrillaga,1998).HighVoltageDirectCurrentTransmission.2ndEdition,1998.
CommonwealthNorth(CWN,2012).EnergyforaSustainableAlaska:TheRuralConundrum.February2012.
DepartmentofCommunityandRegionalAffaris(DCRA,2011).CurrentCommunityConditions:FuelPricesAcrossAlaska,ReporttotheDirector.June2010Update.
DenaliCommission(DenaliCommission,2008a).49CIntertieUpgradeNunapitchuktoKasigluk,CloseoutSummaryReport.June2008.
DenaliCommission(DenaliCommission,2008b).27BToksookBay–TununakInterie,CloseoutSummaryReport.June2008.
DenaliCommission(DenaliCommission,2009).21INightmute–ToksookBayIntertie,AwardTransitionandCloseoutSummaryReport.2009.
DenaliCommission(DenaliCommission,2010).DenaliCommissionExpenseCategorySummary,ProjectNumber01117220607Bethel–NapakiakIntertie.June30,2010.
DenaliCommission(DenaliCommission,2011).70CBrevigMissiontoTellerIntertieAwardTransitionandCloseoutSummaryReport.June30,2011.
Dryden&LaRue,Inc.(Dryden&Larue,2011).FeasibilityStudyReport,OuzinkieLineExtensionofMonashkaFeederHighSubStation.2011.
Ibrahim,Sherif(Ibrahim,2000).PerformanceEvaluationofFiber‐ReinforcedPolymerPolesforTransmissionLines.DoctoralThesis,UniversityofManitoba,DepartmentofCivilandGeologicalEngineering.2000.
IdahoNationalEngineeringandEnvironmentalLaboratory(INEEL,1998).Haines‐SkagwaySubmarineCableIntertieProject,HainestoSkagway,Alaska.FinalTechnicalandConstructionReport.November1998.
Page 660
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE J-4
InsidePassageElectricCooperative,Inc.(IPEC,2009).ElectricTransmissionIntertie,Juneau‐Green'sCreekMine‐Hoonah.PresentationtoSoutheastConferencebyJodiMitchell.2009.
Kuffel,E.,Zaengl,W.S.,&Kuffel,J.(KZK,2006).HighVoltageEngineeringFundamentals.2ndEdition,2006.
Naidu,M.S.&Kamaraju,V.(Naidu,1996).HighVoltageEngineering.2ndEdition,1996.
NationalRenewableEnergyLaboratory(NREL,2005).AlaskaVillageElectricLoadCalculator.ExcelComputerProgram.2005.
NeubauerEngineering&TechSvc.,FosterWheelerEnv.Corp.(Neubauer,1997).RuralAlaskaElectricUtilityInterties.
PentonMediaPublications(TDW,2012).Transmission&DistributionWorld:HVDCTransforminganIndustry.April2012Issue.
PolarconsultAlaska,Inc.(Polarconsult,1986).ManokotakTransmissionLineStudy.June1986.
PolarconsultAlaska,Inc.(Polarconsult,2009).PhaseI–PreliminaryDesignandFeasibilityAnalysisFinalReport.
PowerEngineers(PowerEngineers,2004).Juneau‐GreensCreek/HoonahIntertieStudy,LoadFlowandShortCircuitAnalysisFinalReport,Rev1.December30,2004.
Skrotzki,BernhardtG.A.(Skrotzki,1980).ElectricTransmission&Distribution.1980.
Southwire(Southwire,2008).SouthwireSAG10,Version3.10.7.2008.
Thrash,Ridley,Murah,Amy,Lancaster,Mark,&Nuckles,Kim(Thrash,2007).OverheadConductor.2ndEdition,2007.
U.S.DepartmentofAgriculture‐RuralUtilityService(RUS,1998).SpecificationsandDrawingsfor24.9/14.4kVLineConstruction.Bulletin1728F‐803(D‐803),December1998.
U.S.DepartmentofAgriculture‐RuralUtilityService(RUS,2001).ElectricDistributionLineGuysandAnchors.Bulletin1724E‐153,April2001.
U.S.DepartmentofAgriculture‐RuralUtilityService(RUS,2002).MechanicalLoadingonDistributionCrossArms.Bulletin1724E‐151,November2002.
U.S.DepartmentofAgriculture‐RuralUtilityService(RUS,2003a).UnguyedDistributionPoles‐StrengthRequirements.Bulletin1724E‐150,July2003.
U.S.DepartmentofAgriculture‐RuralUtilityService(RUS,2003b).TheMechanicsofDistributionLineConnectors.Bulletin1724E‐152,July2003.
U.S.DepartmentofAgriculture‐RuralUtilityService(RUS,2003c).DistributionConductorClearancesandSpanLimitations.Bulletin1724E‐154,July2003.
U.S.DepartmentofAgriculture‐RuralUtilityService(RUS,2005).SpecificationsandDrawingsfor12.47/7.2kVLineConstruction.Bulletin1728F‐804,Oct2005.
Page 661
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE J-5
U.S.DepartmentofAgriculture‐RuralUtilityService(RUS,2009).DesignManualforHighVoltageTransmissionLines.Bulletin1724E‐200,May2009.
WHPacificetal.(WHPacific,2008).DistributingAlaska'sPower:ATechnicalandPolicyReviewofElectricTransmissioninAlaska.December2008.
Page 662
FINALREPORT,VERSION1.1 POLARCONSULTALASKA,INC.HVDCTRANSMISSIONSYSTEMFORRURALALASKANAPPLICATIONS PHASEII–PROTOTYPINGANDTESTING
MARCH 2012 PAGE J-6
Thispageintentionallyblank.