Arrowhead-Weston Transmission Line Project Dave Van House Minnesota PowerDescription & OverviewWhy was it proposed?Slide 4Slide 5MinnesotaRecent Regional ProblemsSlide 8Slide 9IMPACT OF June 25, 1998 DISTURBANCESlide 11Slide 12Wisconsin ActionsSlide 14PERFORMANCE EVALUATIONPower Flow AnalysisGenerator ResponseDynamic StabilityVoltage StabilityEngineering to Support PermittingTransmission Line NoiseSlide 23Arrowhead Substation NoiseOther Engineering IssuesSlide 26Opposition to the project:Slide 28Slide 29Common Utility CorridorSlide 31Slide 32954 ACSR 2-Conductor Bundle with Shield WireSingle 3M Composite ConductorPost Permit StudiesEquipment SpecificationsSlide 37Construction Impact StudiesOperating StudiesSummarySlide 41ArrowheadWestonTransmission LineProjectDave Van HouseMinnesota PowerDescription & Overview220 mile 345,000 volt electric transmission lineApproved by the Minnesota and Wisconsin regulators in 2001Construction Began in Minnesota February 2004Construction to Begin in Wisconsin Fall 2004Construction scheduled to be completed in 2008Why was it proposed?Reliability!!Improves Regional System SecurityProvides Maintenance & Operational FlexibilityAllows Customers Greater Access to Generation Sources101002003004005006007001Intertie Capacity vs Energy Usage by StatePer Unit Intertie Capacity (kVA/GWh)Wisconsin Minnesota Iowa Illinois Nebraska S. Dakota N. DakotaRankLastwww.powerupwisconsin.comMinnesota Minnesota’s electric network is tied to neighboring states.If Wisconsin has a problem, Minnesota has a problem.Minnesota Power customers have been knocked off line by electric system disturbances related to the weak Minnesota-Wisconsin connection.Recent Regional ProblemsJune 11, 1997June 25, 1998June 10, 1999IMPACT OF June 25, 1998 DISTURBANCEIN MAPP■60+ TRANSMISSION LINES TRIPPED■4,000+ MW OF GENERATION LOST■More Than 39,000+ CUSTOMERS AFFECTEDIN NW ONTARIO■BLACK OUT TO 113,000 CUSTOMERS■650 MW OF LOAD LOST ■270 MW OF Generation LostWisconsin Actions1997 events raise concerns about electric supply reliability in WisconsinWisconsin utilities and regulators form Wisconsin Reliability Assessment Organization (WRAO)WRAO forms engineering group to study alternatives - WIRES groupPERFORMANCE EVALUATIONDETAILED POWER FLOWS SIMULATIONGENERATOR RESPONSEDYNAMIC STABILITYVOLTAGE STABILITYIMPACT ON MAPPCONSTRUCTION COSTSLOSS EVALUATIONPower Flow AnalysisReactive Voltage Support RequirementsSteady State Maximum Transfer capabilitySensitivity to Modeling AssumptionsTransmission System Loss AnalysisGenerator ResponseMechanical Stress on Weston Generator Shaft ■Large Phase Angle Across MAPP MAIN Interface■Eau Claire Arpin Line Switching■Instanteous change in Power outputDynamic StabilityAbility of Systems Generators to remain synchronized and recover from Major System DisturbanceMAPP WUMS DisturbancesLoss of New FacilitiesImpact on Existing Limiting ConditionsDynamic Reactive Support RequirementsVoltage StabilityAbility of the System to Maintain Adequate Voltage Following a DisturbanceWithout Adequate Voltage Support System can Experience■Increased Current Demand (P = VI)■Slowly Declining Voltage■Loss of Voltage Sensitive Loads■Voltage CollapseEngineering to Support Permitting Calculation of;■AUDIBLE NOISE■ELECTRIC FIELD■MAGNETIC FIELDAnalysis of Potential Farm Impacts■Stray Voltage■Earth CurrentsMagnetic FieldElectric FieldSpark DischargeMultiple RoutesMultiple StructuresMultiple CircuitsMultiple FlowsFuture YearsEMF IssuesTransmission Line NoiseDue to Corona Discharge■Electric Field at surface of the conductor exceeds the breakdown strength of air■Generates light, audible noise radio noise and energy lossesMitigation■Increase Conductor Surface area•Larger Conductors•Multiple conductorsSubstation Noise MonitoringLong TermShort TermExistingEquipmentImpact ofAdditionsArrowhead Substation NoiseOther Engineering IssuesDifferential GPS Interference (Precision Farming)Electric & Magnetic Field ■Impacts on Pacemakers and implantable Defibulators■Impacts on Railroad, Pipeline and AM Radio Transmitter sitesOpposition to the project:Save Our Unique LandsCitizens Utility BoardWisconsin Environmental DecadeNorth American Water OfficeHillside DairyWorld Organization of Landowner FreedomCommon Utility CorridorVisual Impact Of CrossingExisting 161 kV H-Frame954 ACSR 2-ConductorBundle with Shield WireSingle 3M Composite ConductorPost Permit StudiesEquipment SpecificationConstruction Support AnalysisOperating studiesEquipment SpecificationsTransient studies■Breaker Switching Duties•Shunt Reactor•Shunt Capacitor•345 & 230 kV line breakers■Capacitor Bank Switching Issues•Voltage Magnification■Insulation Coordination•Surge Arrester rating & placement•Equipment BIL requirements•Line InsulationConstruction Impact StudiesConstructability■Line outage concerns■Maintenance issues■Ownership IssuesIncreased CostLandowner OppositionOperating StudiesDetermination of Operating Limits■Reactive Support Requirements•Shunt Capacitor location optimization■Line Loadability Issues•System Intact and Post Contingency■Phase Shifter Requirements•Line load sharing optimization•Post Contingency requirements■New Flow-Gate Limits•System Intact and Post ContingencySummaryOperating experience has shown there is a significant risk to electrical reliability in the upper Midwest and WisconsinEngineering study commissioned through Assembly Act 204WRAO recommendation Arrowhead Weston 345 kV LineSummaryThe Arrowhead-Weston Project will substantially alleviate the reliability problems being experienced due to the weak electrical tie between the upper Midwest and Wisconsin.It will also provide import capability for Wisconsin to meet its emergency power supply
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