Arrowhead - Weston Transmission Line Project Dave Van House Minnesota Power

1. Arrowhead-WestonTransmission LineProjectDave Van HouseMinnesota Power

2. Description & Overview • 220 mile 345,000 volt electric transmission line • Approved by the Minnesota and Wisconsin regulators in 2001 • Construction Began in Minnesota February 2004 • Construction to Begin in Wisconsin Fall 2004 • Construction scheduled to be completed in 2008

3. Why was it proposed? Reliability!! • Improves Regional System Security • Provides Maintenance & Operational Flexibility • Allows Customers Greater Access to Generation Sources

6. Minnesota • 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. www.powerupwisconsin.com

7. Recent Regional Problems • June 11, 1997 • June 25, 1998 • June 10, 1999

10. IMPACT OF June 25, 1998 DISTURBANCE • IN MAPP • 60+ TRANSMISSION LINES TRIPPED • 4,000+ MW OF GENERATION LOST • More Than 39,000+ CUSTOMERS AFFECTED • IN NW ONTARIO • BLACK OUT TO 113,000 CUSTOMERS • 650 MW OF LOAD LOST • 270 MW OF Generation Lost

13. Wisconsin Actions • 1997 events raise concerns about electric supply reliability in Wisconsin • Wisconsin utilities and regulators form Wisconsin Reliability Assessment Organization (WRAO) • WRAO forms engineering group to study alternatives - WIRES group

15. PERFORMANCE EVALUATION • DETAILED POWER FLOWS SIMULATION • GENERATOR RESPONSE • DYNAMIC STABILITY • VOLTAGE STABILITY • IMPACT ON MAPP • CONSTRUCTION COSTS • LOSS EVALUATION

16. Power Flow Analysis • Reactive Voltage Support Requirements • Steady State Maximum Transfer capability • Sensitivity to Modeling Assumptions • Transmission System Loss Analysis

17. Generator Response • Mechanical Stress on Weston Generator Shaft • Large Phase Angle Across MAPP MAIN Interface • Eau Claire Arpin Line Switching • Instanteous change in Power output

18. Dynamic Stability • Ability of Systems Generators to remain synchronized and recover from Major System Disturbance • MAPP WUMS Disturbances • Loss of New Facilities • Impact on Existing Limiting Conditions • Dynamic Reactive Support Requirements

19. Voltage Stability • Ability of the System to Maintain Adequate Voltage Following a Disturbance • Without Adequate Voltage Support System can Experience • Increased Current Demand (P = VI) • Slowly Declining Voltage • Loss of Voltage Sensitive Loads • Voltage Collapse

20. Engineering to Support Permitting • Calculation of; • AUDIBLE NOISE • ELECTRIC FIELD • MAGNETIC FIELD • Analysis of Potential Farm Impacts • Stray Voltage • Earth Currents

21. EMF Issues • Magnetic Field • Electric Field • Spark Discharge • Multiple Routes • Multiple Structures • Multiple Circuits • Multiple Flows • Future Years

22. Transmission Line Noise • Due to Corona Discharge • Electric Field at surface of the conductor exceeds the breakdown strength of air • Generates light, audible noise radio noise and energy losses • Mitigation • Increase Conductor Surface area • Larger Conductors • Multiple conductors

23. Substation Noise Monitoring • Long Term • Short Term • ExistingEquipment • Impact ofAdditions

24. Arrowhead Substation Noise

25. Other Engineering Issues • Differential GPS Interference (Precision Farming) • Electric & Magnetic Field • Impacts on Pacemakers and implantable Defibulators • Impacts on Railroad, Pipeline and AM Radio Transmitter sites

27. Opposition to the project: • Save Our Unique Lands • Citizens Utility Board • Wisconsin Environmental Decade • North American Water Office • Hillside Dairy • World Organization of Landowner Freedom

30. Common Utility Corridor

31. Visual Impact Of Crossing

32. Existing 161 kV H-Frame

33. 954 ACSR 2-ConductorBundle with Shield Wire

34. Single 3M Composite Conductor

35. Post Permit Studies • Equipment Specification • Construction Support Analysis • Operating studies

36. Equipment Specifications • Transient 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 Insulation

38. Constructability Line outage concerns Maintenance issues Ownership Issues Increased Cost Landowner Opposition Construction Impact Studies

39. Operating Studies • Determination 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 Contingency

40. Summary • Operating experience has shown there is a significant risk to electrical reliability in the upper Midwest and Wisconsin • Engineering study commissioned through Assembly Act 204 • WRAO recommendation Arrowhead Weston 345 kV Line

41. Summary • The 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 requirements.