Northern States Power Company Wisconsin. Application for a Certificate of Public Convenience and Necessity

Transcription

1 Northern States Power Company Wisconsin Application for a Certificate of Public Convenience and Necessity for the Stone Lake to Couderay 6 kv Rebuild/6 kv Upgrade Transmission Project PSC Docket No CE-76 September 20 Volume III Appendices D through I

2 Stone Lake to Couderay Transmission System Upgrade Sawyer County, WI Application for Certificate of Public Convenience and Necessity and Utility Permit Appendix D APPIX D Transmission Study Xcel Energy Appendix D September 20

3 Northwest Wisconsin Load-Serving Study By: Participants: Jeffrey Norman Daniel Kline American Transmission Company Dairyland Power Cooperative Xcel Energy, Inc. 4/23/2008

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5 Background & Conclusions Executive Summary This study is being performed to address various load-serving problems in Sawyer, Rusk, and Chippewa counties in northwest Wisconsin. The existing transmission system cannot support expected load growth in this area after 202 under post-contingent conditions(n-). Apart from these above problems, Enbridge Energy is proposing to upgrade its facilities by 202, adding significant load to the 6 kv system between Osprey and Stone Lake and also to the 5 kv system south of Osprey. The recommended plan is to build a 7-mile 6 kv line from Stone Lake Substation to a new 6 kv switchyard at Couderay Substation with a 70 MVA 6/6 kv transformer at Couderay. The estimated cost of this option is $4,350,000 with a proposed in-service date of June, 202. Figure : Stone Lake Area System Farmers Inn To Arrowhead To Minong To Hayward and Farmers Inn To Washco Stone Lake 0. mi Stone Lake Pump 2.5 mi 6.2 mi Sand Lake.3 mi Couderay Edgewater Pump.3 mi To Gardner Park.5 mi To Park Falls To Prentice N Key 345 kv 6 kv 5 kv 6 kv Trails End Big Falls 8.7 mi 7.2 mi 0.0 mi White Tail Osprey To Sheldon Xcel Energy, Inc. 2 4/23/2008

6 Background & Conclusions Figure 2: Option H Stone Lake-Couderay 6 kv Farmers Inn To Arrowhead To Minong To Hayward and Farmers Inn To Washco Stone Lake 0. mi Stone Lake Pump 2.5 mi 6.2 mi Sand Lake.3 mi Couderay Edgewater Pump.3 mi 7. mi To Gardner Park.5 mi To Park Falls To Prentice N Key 345 kv 6 kv 5 kv 6 kv Trails End Big Falls 8.7 mi 7.2 mi 0.0 mi White Tail Osprey To Sheldon The alternative fix is to rebuild 56 miles of 6 kv line between Stone Lake and Osprey, install additional capacitors at Edgewater 6 kv Substation, and replace the existing 70 MVA 6/6 kv transformer at Stone Lake with a 2 MVA transformer. The estimated cost of this option is about $2,500,000. Xcel Energy conducted this load serving study in consultation with American Transmission Company and Dairyland Power Cooperative to develop a robust long-range plan for this area. Xcel Energy, Inc. 3 4/23/2008

7 Background & Conclusions Table of Contents. Background Conclusion Transmission Deficiencies in Study Area Analysis Financial Analysis... 8 Development of Route and Configuration Alternatives... i Route and Configuration Alternative One-Lines...iii Power Flow Contingency File... v Power Flow System Monitor File...xlii Power Flow Subsystem File... xliv List of Tables TABLE : SYSTEM DEFICIENCIES... 7 TABLE 2: STUDY AREA LOAD LEVELS... 0 TABLE 3: THERMAL OVERLOADS ALLEVIATED BY OPTION A... TABLE 4: THERMAL OVERLOADS ALLEVIATED BY OPTION B... 2 TABLE 5: THERMAL OVERLOADS ALLEVIATED BY OPTION C... 2 TABLE 6: THERMAL OVERLOADS ALLEVIATED BY OPTION D... 3 TABLE 7: THERMAL OVERLOADS ALLEVIATED BY OPTION E... 3 TABLE 8: THERMAL OVERLOADS ALLEVIATED BY OPTION F... 5 TABLE : THERMAL OVERLOADS ALLEVIATED BY OPTION G... 6 TABLE 0: THERMAL OVERLOADS ALLEVIATED BY OPTION H... 6 TABLE : OPTION D FINANCIAL ANALYSIS... 8 TABLE 2: OPTION E FINANCIAL ANALYSIS... 8 TABLE 3: OPTION F FINANCIAL ANALYSIS... 8 List of Figures FIGURE : STONE LAKE AREA SYSTEM... 2 FIGURE 2: OPTION H STONE LAKE-COUDERAY 6 KV... 3 FIGURE 3: QV ANALYSIS OF STONE LAKE EDGEWATER PUMP 6 KV RECONDUCTOR... 4 FIGURE 4: OPTION F PROJECTED STONE LAKE 6/6 KV TRANSFORMER LOADING LEVELS... 5 Xcel Energy, Inc. 4 4/23/2008

8 Background & Conclusions. Background The study area consists of the region served by the 6 kv line between Stone Lake and Osprey Substations and the 5 kv system south of Osprey Substation in northwest Wisconsin. As Enbridge Energy expands their pumping operations and load in the area grows, new high voltage transmission lines are needed to support the area. 2. Conclusion The recommended plan is to build Option H, as described below, by 202. This option fixes the overloads of the Sand Lake-Stone Lake Pump 6 kv line, the Big Falls- White Tail 6 kv line, and the Stone Lake 6/6 kv transformer. This option also fixes voltage issues caused by the outage of the Stone Lake Pump to Stand Lake 6 kv line. ) Option H a. Construct a 6 kv bus at Couderay b. Expand the Stone Lake 6 kv switchyard to accept a new line termination c. Construct a Stone Lake-Couderay 6 kv line d. Install a 6/6 kv LTC transformer at Couderay e. Install the following substation equipment at Couderay: i. 6 kv motor-operated switch (high-side transformer) ii. 6 kv motor-operated switch (low-side transformer) iii. 6 kv circuit breaker (looking toward Stone Lake Substation) The proposed configuration would leave in place the existing circuit breaker that looks toward NCP s Stacik Substation. The new 6 kv circuit breaker would look toward Stone Lake. The 6 kv line cannot be double-circuited with the existing 6 kv line and still address the overloads associated with the outage of the Stone Lake Pump to Stand Lake 6 kv line. In order to double-circuit Option H, the new 6 kv line would need to be extended to Osprey by 202. This would require at least 30 miles of additional 6 kv line to be constructed by 202. The added capital expenditure for this would likely be in excess of $8,000,000. Xcel Energy, Inc. 5 4/23/2008

9 Background & Conclusions Xcel Energy, Inc. 6 4/23/2008

10 Transmission Deficiencies 3. Transmission Deficiencies in Study Area The analysis was performed on the MRO 2007 Series 202 and 207 summer peak model. Load in this region is mainly served by a 6 kv line connecting the Stone Lake and Osprey Substations. The thermal overloads that were found and addressed through this study were the Stone Lake 6/6 kv transformer and the Stone Lake Pump-Sand Lake 6 kv line. Both overloads are present only under post-contingent (N-) conditions, see Table. The voltage issues addressed in this study are on the Ironwood and Gogobec 34.5 and 88 kv systems and the Osprey and Stone Lake area 6 kv system. The system deficiencies uncovered during base case analysis that this study attempts to address are listed below in Table. The deficiencies labeled 207 indicate that the limiter shows up in the 207 model but not in the 202 model. Deficiencies labeled 202 are limiters in both the 202 and the 207 models. Table : System Deficiencies 202 Stone Lake Pump-Sand Lake 6 kv Contingent Flow (MVA) Holcombe-Cornell 5 kv Year Monitored Element Contingency Continuous Rating (MVA) 202 Stone Lake 6/6 kv Stone Lake-Farmers Inn Transformer 6 kv 202 Stone Lake 6/6 kv Stone Lake-Farmers Inn- Transformer Gingles 6 kv 202 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell- Anderson-Jim Falls 5 kv Loading Level (%) 202 White Tail-Big Falls 6 kv Stone Lake Pump-Sand Lake 6 kv 202 White Tail-Trails End 6 kv Stone Lake Pump-Sand Lake 6 kv 207 Stone Lake Pump-Sand Lake 6 kv White Tail-Osprey 6 kv Year Contingency Bus* Voltage 202 Loss of Gingles-Hurley 5 kv line Mine Road 34.5 kv Loss of Ironwood-Park Falls 5 kv line Mine Road 34.5 kv Loss of Stone Lake-Farmers Inn 6 kv line Herb Street 34.5 kv Loss of Farmers Inn-Gingles 6 kv line Herb Street 34.5 kv Loss of Stone Lake-Farmers Inn-Gingles 6 kv line Herb Street 34.5 kv Loss of White Tail-Osprey 6 kv line White Tail 6 kv Loss of Stone Lake Pump-Sand Lake 6 kv line Sand Lake 6 kv Loss of Sheldon Pump-Holcombe 5 kv line Herb Street 34.5 kv 0.8 *Only the lowest voltage was listed per contingency Xcel Energy, Inc. 7 4/23/2008

11 Electrical Analysis 4. Analysis 4. Models All study analysis was performed on 2007 series 202 and 207 summer peak models. The models are updated with Xcel Energy loads and input from ATC and DPC. The models include the Arrowhead-Weston 345 kv line. The models do not include the Chisago Co-Apple River line. The performance of the options was tested to meet the voltage and line loading criteria for NERC category A, B and C contingencies. Voltages must be within ten percent of nominal voltage post contingent. Line loadings cannot exceed the continuous rating (rate A) under system intact conditions and cannot exceed their emergency rating under post-contingent conditions (N-). Emergency ratings are only valid for the first thirty minuets after an outage at which point continuous ratings apply. Contingencies were performed on the following: Stinson Lakeside 5 kv Line Bayfront Ashland 6 kv Line Bayfront Gingles 5 kv Line Gingles Hurley 5 kv Line Ironwood Hurley 5 kv Line Ironwood Park Falls 5 kv Line Stone Lake - Gingles 6 kv Line Stone Lake Washco 6 kv Line Stone Lake 345/6 kv Transformer # Osprey Sheldon Pump 5 kv Line Sheldon Pump Holcombe 5 kv Line Holcombe Cornell 5 kv Line Hydro Lane Jim Falls 5 kv Line Stone Lake Stone Lake Pump 6 kv Line White Tail Osprey 6 kv Line Stinson Phase Shifter All 6, 5 and 38-kV Category B contingencies plus ties within the ATC portion of the study area All 345-kV Category B contingencies plus ties within ATC o Eau Claire-Arpin 345 kv o King-Eau Claire-Arpin 345 kv Weston #4 (550 MW) Oak Creek # (650 MW) Kewaunee # (57 MW) Columbia # (520 MW) Presque Isle #6 (80 MW) Pulliam #8 (32 MW) Xcel Energy, Inc. 8 4/23/2008

12 Electrical Analysis The Alliant East, DPC, WPS, WE and Xcel Energy control areas were monitored for violations. The various options considered for the study region are discussed in section 4.2. Xcel Energy, Inc. 4/23/2008

13 Electrical Analysis Loads in the study area were increased to their actual summer peak levels and pump loads were increased to the forecasted levels provided by Enbridge Energy. The buses in the table below will see their load levels increased to the levels indicated for the 202 and 207 cases. Table 2: Study Area Load Levels Substation Bus Number Load ID 2SUPK MVAR7SUPK MVAR XEL Sand Lake 6 kv 6205 X XEL Farmers Inn 6 kv X XEL Stone Lake Pump 6 kv 6205 X XEL Edgewater Pump 5 kv 636 X XEL Big Falls 6 kv 6027 X XEL Sheldon Pump 6 kv 6026 X XEL City Forest 6 kv 6208 X XEL White Tail 6 kv 6206 X XEL Ladysmith Pump 6 kv 6204 X XEL Doughty Road 6 kv 6207 X XEL Trails End 6 kv 630 X XEL Cameron 6 kv 6074 X XEL Rice Lake 6 kv XEL Birchwood 6 kv 6065 X XEL North Fork 34.5 kv 638 X XEL Butternut 34.5 kv 60 X XEL Sanguine 34.5 KV 60 X XEL Mellen 34.5 kv 607 X XEL Iron Belt 34.5 kv 605 X XEL Montreal 34.5 kv 608 X XEL Ironwood 34.5 kv X XEL Hurley 5 kv 6028 X XEL Saxon Pump 88 kv 604 X XEL Great Lakes 88 kv 620 X XEL Gogebic 88 kv 622 X XEL Ino Pump 5 kv 602 X XEL Owen 6 kv 604 X XEL Glidden 34.5 kv 606 X Xcel Energy, Inc. 0 4/23/2008

14 Electrical Analysis 4.2 Options Studied Option A: Prentice-Clear Lake 5 kv Line: Option A is a new 5 kv line from the Prentice Substation to ATC s Clear Lake Substation southeast of Minocqua. This option helps in addressing the low voltage issues associated with the Ironwood-Hurley 5 kv outage at Pine Lake. Option A also fixes the Stone Lake Pump-Sand Lake 6 kv overload for the outage of Holcombe-Cornell 5 kv or the Holcombe-Cornell-Anderson-Jim Falls 5 kv outage. Option A did not address the Stone Lake 6/6 kv transformer issues or the low voltage issues on the Stone Lake, Edgewater, North Central, White Tail, Trails End or Big Falls 6 kv buses. Due to the fact that the above system deficiencies were not addressed, Option A is not considered a viable option. Table 3: Thermal Overloads Alleviated by Option A Year Limiting Element Contingency 202 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell 5 kv 202 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell-Anderson-Jim Falls 5 kv 207 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell 5 kv 207 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell-Anderson-Jim Falls 5 kv 207 Gardner Park-Black Brook 5 kv Gardner Park-Kelly 5 kv 207 Gardner Park-Black Brook 5 kv Maine-Hilltop 5 kv 207 Gardner Park-Black Brook 5 kv Maine-Pine 5 kv 207 Metomen 38/6 kv Transformer System Intact 207 Wheaton-Presto Tap 6 kv Weston Unit Dayton-T RC 6 kv WKA-Grangrae 6 kv 207 Tomahawk-Sparta 6 kv Sigel-Arpin 38 kv 207 Tomahawk-Sparta 6 kv Council Creek (DPC)-Oakdale 6 kv Option B: Prentice-Highway 8 5 kv Line: Option B is a new 5 kv line from Prentice Substation to ATC s Highway 8 Substation. This option addresses several low voltage issues in the ATC control area. It also helps in addressing the low voltage issues associated with the Ironwood-Hurley 5 kv outage at Pine Lake. In addition, this option fixes the Stone Lake Pump-Sand Lake 6 kv overload for the outage of Holcombe-Cornell 5 kv or the Holcombe-Cornell- Anderson-Jim Falls 5 kv outage. As with Option A, Option B did not address the Stone Lake 6/6 kv transformer issues or the low voltage issues on the Stone Lake, Edgewater, North Central, White Tail, Trails End or Big Falls 6 kv buses. Due to the fact that the above system deficiencies were not addressed, Option B is not considered a viable option. Xcel Energy, Inc. 4/23/2008

15 Electrical Analysis Table 4: Thermal Overloads Alleviated by Option B Year Limiting Element Contingency 202 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell 5 kv 202 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell-Anderson-Jim Falls 5 kv 207 Gardner Park-Black Brook 5 kv Gardner Park-Kelly 5 kv 207 Gardner Park-Black Brook 5 kv Maine-Hilltop 5 kv 207 Gardner Park-Black Brook 5 kv Maine-Pine 5 kv Option C: Prentice-Tomahawk 5 kv Line: Option C is a new 5 kv line from Prentice Substation to ATC s Tomahawk Substation. This option addresses several low voltage issues in the ATC control area. It also helps in addressing the low voltage issues associated with the Ironwood-Hurley 5 kv outage at Pine Lake. Additionally, Option C fixes the Stone Lake Pump-Sand Lake 6 kv overload for the outage of Holcombe-Cornell 5 kv or the Holcombe-Cornell- Anderson-Jim Falls 5 kv outage. As with Options A and B, Option C did not address the Stone Lake 6/6 kv transformer issues or the low voltage issues on the Stone Lake, Edgewater, North Central, White Tail, Trails End or Big Falls 6 kv buses. Due to the fact that the above system deficiencies were not addressed, Option C is not considered a viable option. Table 5: Thermal Overloads Alleviated by Option C Year Limiting Element Contingency 202 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell 5 kv 207 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell-Anderson-Jim Falls 5 kv 207 Gardner Park-Black Brook 5 kv Gardner Park-Kelly 5 kv 207 Gardner Park-Black Brook 5 kv Maine-Hilltop 5 kv 207 Gardner Park-Black Brook 5 kv Maine-Pine 5 kv Option D: Big Falls-Stone Lake 6 kv Line: Option D is a new 6 kv line between Stone Lake and Osprey Substations. This option addresses several low voltage issues in the Ironwood area and also fixes the Stone Lake Pump-Sand Lake 6 kv overload for the outage of Holcombe-Cornell 5 kv or the Holcombe-Cornell-Anderson-Jim Falls 5 kv outage. Unlike Options A, B, and C, Option D addresses the Stone Lake 6/6 kv transformer issues associated with the outage of the Stone Lake-Farmers Inn 6 kv line. Option D failed to address the 6 kv overloads or the voltage issues on the Stone Lake, Edgewater, North Central, White Tail, Trails End or Big Falls 6 kv buses. As Option H demonstrates, these issues may be fixed by installing a 6/6 kv transformer on the Big Falls-Stone Lake 6 kv line at Couderay. Xcel Energy, Inc. 2 4/23/2008

16 Electrical Analysis Table 6: Thermal Overloads Alleviated by Option D Year Limiting Element Contingency 202 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell 5 kv 202 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell-Anderson-Jim Falls 5 kv 202 Stone Lake 6/6 kv Transformer Stone Lake-Farmers Inn 6 kv 202 Stone Lake 6/6 kv Transformer Stone Lake-Farmers Inn-Gingles 6 kv 202 Wheaton-Presto Tap 6 kv System Intact 202 Eau Claire-Presto Tap 6 kv System Intact 202 Eau Claire 6/6 kv Transformer Hydro Lane-Wheaton Tap-Red Cedar 6 kv Option E: Stone Lake-Edgewater Pump 6 kv Reconductor: Option E proposes to reconductor the 6 kv line from Stone Lake Pump-Sand Lake-Edgewater. This option fixes the Stone Lake Pump-Sand Lake 6 kv overload for the outage of the Holcombe-Cornell 5 kv line or the Holcombe-Cornell-Anderson-Jim Falls 5 kv outage. This option has no impact on voltages. Option E did not address the Stone Lake 6/6 kv transformer issues or the low voltage issues on the Stone Lake, Edgewater, North Central, White Tail, Trails End or Big Falls 6 kv buses. Due to the fact that the above system deficiencies were not addressed, Option E is not considered a viable option. Table 7: Thermal Overloads Alleviated by Option E Year Limiting Element Contingency 202 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell 5 kv 202 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell-Anderson-Jim Falls 5 kv 207 Stone Lake Pump-Sand Lake 6 kv White Tail-Big Falls 6 kv Figure 3 shows a graph of the VQ analysis that was performed on Option E to identify the amount of capacitance required to address the voltage issues caused by the Stone Lake Pump to Sand Lake 6 kv outage. It was determined that seven 7.2 MVAR capacitor banks would be needed. Three 7.2 MVAR capacitor steps would be placed at Sand Lake 6 kv substation with two 7.2 MVAR steps placed at Edgewater and Couderay 6 kv substations. Xcel Energy, Inc. 3 4/23/2008

17 Electrical Analysis Figure 3: QV Analysis of Stone Lake Edgewater Pump 6 kv Reconductor By installing the capacitors identified above along with a 2 MVA 6/6 kv transformer at Stone Lake Substation and rebuilding the Big Falls-White Tail-Trails End 6 kv line, Option E becomes a viable option. Option F: Stone Lake-Edgewater 6 kv Line: Option F is a new 6 kv line from Stone Lake Substation to a new 6 kv bus at Edgewater Substation. The Edgewater 6 kv load will be moved to the new 6 kv bus. In order to provide adequate space for new 6 kv equipment, this option requires that the existing 6 kv capacitors at Edgewater Substation be moved to Sand Lake Substation and the existing switchyard be expanded. No new Edgewater 6/6 kv transformer is included as part of this plan. This option fixes the Stone Lake Pump-Sand Lake 6 kv overload for the outage of Holcombe-Cornell 5 kv or the Holcombe-Cornell- Anderson-Jim Falls 5 kv outage. It also fixes the Stone Lake 6/6 kv transformer issues associated with the outage of the Stone Lake-Farmers Inn 6 kv line for 202. The incremental load serving capabilities of Option F are determined by taking a linear approximation of loading levels between 202 and 207. Using this method, Xcel Energy, Inc. 4 4/23/2008

18 Electrical Analysis Option F will serve area load through 205 but more fixes would be needed by summer peak 206. See graph below: Figure 4: Option F Projected Stone Lake 6/6 kv Transformer Loading Levels Stone Lake 6/6 kv Transformer Loading Levels Load (MW) Estimated Loading Levels of the Stone Lake 6/6 kv tx Assuming Linear Load Growth Thermal Emergency Rating of the Stone Lake 6/6 kv TX Year Option F did not address the low voltage issues on the Stone Lake, Edgewater, North Central, White Tail, Trails End or Big Falls 6 kv buses, or the Stone Lake 6/6 kv transformer loading issues after 205. Due to the fact that the above system deficiencies were not addressed, Option F is not considered a viable option. Table 8: Thermal Overloads Alleviated by Option F Year Limiting Element Contingency 202 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell 5 kv 202 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell-Anderson-Jim Falls 5 kv 202 Stone Lake 6/6 kv Transformer Stone Lake-Farmers Inn 6 kv 202 Stone Lake 6/6 kv Transformer Stone Lake-Farmers Inn-Gingles 6 kv 207 Stone Lake Pump-Sand Lake 6 kv White Tail-Big Falls 6 kv By installing the capacitors identified in the analysis of Option E along with a 2 MVA 6/6 kv transformer at Stone Lake Substation and rebuilding the Big Falls- White Tail-Trails End 6 kv line (approximately 6 miles of rebuild), Option F becomes a viable option. Xcel Energy, Inc. 5 4/23/2008

19 Electrical Analysis Option G: Ironwood-Gogebic 5 kv Gogebic-Watersmeet-Lakota Road 38 kv Line: Option G requires rebuilding the Ironwood-Gogebic 88 kv line to 5 kv then stepping the voltage up to 38 kv where it would meet a new 38 kv line from Gogebic to the ATC Watersmeet and Lakota Road 38 kv Substations. This option does not fix any of the Stone Lake area issues and is not considered a viable option. Table : Thermal Overloads Alleviated by Option G Year Limiting Element Contingency 207 Gardner Park-Black Brook 5 kv Gardner Park-Kelly 5 kv 207 Gardner Park-Black Brook 5 kv Main E-Hill Top 5 kv 207 Gardner Park-Black Brook 5 kv Main E-Pine 5 kv Option H: Stone Lake-Couderay 6 kv Line: Option H is a new 6 kv line between Stone Lake and Couderay Substations with a 6/6 kv transformer at Couderay. This option addresses all low voltage issues caused by the outage of the Stone Lake Pump to Sand Lake 6 kv or White Tail-Big Falls 6 kv lines. Option H also fixes the Stone Lake Pump-Sand Lake 6 kv overload for the outage of Holcombe-Cornell 5 kv or the Holcombe-Cornell-Anderson-Jim Falls 5 kv outage. Option H addresses the Stone Lake 6/6 kv transformer issues associated with the outage of the Stone Lake-Farmers Inn 6 kv line. Table 0: Thermal Overloads Alleviated by Option H Year Limiting Element Contingency 202 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell 5 kv 202 Stone Lake Pump-Sand Lake 6 kv Holcombe-Cornell-Anderson-Jim Falls 5 kv 202 Stone lake Pump-Sand Lake 6 kv Whit Tail-Big Fall 6 kv 202 White Tail-Trails End 6 kv Stone Lake Pump-Sand Lake 6 kv 202 Big Falls-White Tail 6 kv Stone Lake Pump-Sand Lake 6 kv 202 Stone Lake 6/6 kv transformer Stone Lake-Farmers Inn 6 kv 202 Stone Lake 6/6 kv transformer Stone Lake-Farmers Inn-Gingles 6 kv 207 Holcombe-Cornell 5 kv Gingles-Hurley 5 kv 207 Holcombe-Cornell 5 kv Bayfront-Gingles 5 kv Option H is the only option that successfully addresses all of the Stone Lake and Osprey area concerns. The 6 kv line cannot be double-circuited with the existing 6 kv line in order for it to address the overloads and low voltages associated with the outage of the Stone Lake Pump to Sand Lake 6 kv line. If the 6 kv line was doublecircuited, it would not address any of the 6 kv voltage or line loading issues caused by the outage of Stone Lake Pump-Sand Lake 6 kv. This is due to the fact that the doublecircuit outage of the new 6 kv line and the Stone Lake Sand Lake 6 kv line would have be considered a NERC contingency under the TPL standards. This double-circuit Xcel Energy, Inc. 6 4/23/2008

20 Electrical Analysis contingency would leave the system in the same condition it is in today during the loss of only the 6 kv line. As noted above, Option H alleviates these issues if the line is not doublecircuited. In order to double-circuit Option H with the existing 6 kv line, the new 6 kv line would need to be extended to Osprey Substation by 202. This would require at least 30 miles of additional 6 kv line and an additional 6/5 kv transformer (at Osprey) to be installed by 202. To further support Option H, a TLTG analysis was performed that slowly stepped up load in the study area to approximate when the proposed 6 kv line would need to be extended to Osprey Substation. The results of that analysis show that, even after taking into account fluctuations in load growth, the proposed solution will last until well beyond 2030, at which time the final 30 miles of line would need to be constructed in order to connect the line to Osprey Substation. These results indicate that the line to Osprey would be needed for regional reliability before it will be needed for local load serving between Stone Lake and Osprey. The benefit of a completed Stone Lake-Osprey 6 kv line is that it would cut the large 6 and 5 kv loop between Ironwood and Eau Claire, Wisconsin in half. This would help address voltage and thermal issues that may be caused by the loss of either end of the loop. Xcel Energy, Inc. 7 4/23/2008

21 Financial Analysis 5. Financial Analysis The financial analysis is an indicative analysis only and is intended for comparing the options at high level. Due to the fact that only Options D, E, F, and H were considered viable options, only these four options were considered in the financial analysis. The following tables detail the estimated cost of constructing the facilities to address the 202 summer peak issues. Table : Option D Financial Analysis Option D Upgrade Mileage Cost Osprey Substation $3,580, Stone Lake Substation $800, Stone Lake-Osprey 6 kv line 56 $32,200, Couderay 6 kv Substation $2,00, Stone Lake 6 kv capacitor bank $475, Total $3,55, Table 2: Option E Financial Analysis Option E Upgrade Mileage Cost Stone Lake-Edgewater 6 kv Rebuild 8.7 $2,32, Big Falls-Trails End 6 kv Rebuild 5. $4,372, x7.2 MVAR 6 kv cap banks at 3 sites $2,250, Stone Lake 2 MVA 6/6 kv TX $3,580, Total $2,55, Option F would require additional facilities to address the 207 summer peak issues by 206 (see section 4). Table 3: Option F Financial Analysis Option F Upgrade Mileage Cost Stone Lake Substation $800, Stone Lake-Edgewater 6 kv line 8.7 $5,002, Big Falls-Trails End 6 kv Rebuild 5. $4,372, x7.2 MVAR 6 kv cap banks at 3 sites $2,250, Total $2,425, Table 4: Option H Financial Analysis Xcel Energy, Inc. 8 4/23/2008

22 Financial Analysis Option H Upgrade Mileage Cost Stone Lake Substation $800, Stone Lake-Couderay 6 kv line 8.7 $,47, Couderay 2 MVA 6/6 kv TX* $3,580, Total $4,327, *2 MVA used for estimate. 70 MVA transformer is required. While Option H has a slightly higher installed cost than Options E and F, it provides a much more robust, longer-term solution than either Option E or Option F. In addition, the 6 kv line proposed could be extended to Osprey Substation when the need arises. While Options E, and F address thermal overload issues past the scope of this particular study, their effectiveness is particularly limited in the scope of how much voltage support is provided to the area. Specifically, Options E and F require the installation of significant amounts of capacitance. Installed capacitance at the levels proposed could lead to voltage flicker problems during switching. Option D provides very robust support to the system in the area, but it proposes more new construction than is necessary at this time. When all factors are considered, Option H would provide a significant increase in reliability to Xcel Energy s northwest Wisconsin service territory, and it would do so at a good value when compared to its alternatives. Xcel Energy, Inc. 4/23/2008

23 Appendix A Development of Route and Configuration Alternatives The Public Service Commission of Wisconsin (PSCW) requires that any project under consideration before it have a robust discussion of alternatives, including alternative routes and configurations for any new transmission lines being proposed. In consideration of these requirements, a discussion of alternatives was undertaken that sought to develop two or more alternatives for presentation to the PSCW. These alternatives, outlined below, will be brought forward to the PSCW during the permitting proceedings that will accompany this line.. 6 kv line from Stone Lake Substation to Couderay Substation using existing right-of-way through Lac Courte Oreilles reservation lands. This line would be on separate structures from the existing 6 kv line. 2. Double-circuit 6/6 kv line from Stone Lake Substation to Couderay Substation using existing right-of-way through Lac Courte Oreilles reservation lands. 3. Conversion of existing 6 kv line from Osprey to Couderay to 6 kv and installation of 6/6 kv transformer at Couderay. This line would involve conversion of the Trails End Substation to 6 kv and would also require approximately 7.2 miles of double-circuit 6/6 kv construction in order to maintain service to the Ladysmith, Wisconsin area. Two-way transmission service to Ladysmith would be obtained by constructing a short Doughty Road Doughty Road Tap 6 kv line. The 6 kv line between Stone Lake and Osprey Substations passes through the Lac Courte Oreilles tribal lands on a 00-foot easement that Xcel Energy maintains. Options and 2 both utilize this right-of-way. Option would place the two lines on separate structures in order to avoid the 6 /6 kv double-circuit outage. Such an outage could result in voltage problems on the 6 kv system in the area. Option 2 involves double-circuiting the 6 and 6 kv circuits. Despite the voltage problems that could result on the 6 kv system, this does not constitute a NERC Category C (TPL-003-0) violation, as NERC requirements apply to systems 00 kv and higher. While Option 2 involves one set of transmission poles, it comes with an added cost of nearly $6.4 million. More detailed scoping estimates for the three options above are provided below. Option Upgrade Mileage Cost Stone Lake Substation $800,000 Stone Lake - Couderay 6 kv line 7. $5,378,000 Xcel Energy, Inc. i 4/23/2008

24 Appendix A Stone Lake - Couderay 6 kv line.6 $3,202,000 Couderay 6 kv Substation $3,650,000 Total $3,030,000 Option 2 Upgrade Mileage Cost Stone Lake Substation $800,000 Stone Lake - Couderay 6 kv line (portion of double-circuit cost) 7. $,376,000 Stone Lake - Couderay 6 kv line (portion of double-circuit cost).6 $3,55,000 Couderay 6 kv Substation $3,650,000 Total $,42,000 Option 3 Upgrade Mileage Cost Osprey Substation $3,580,000 Osprey - Couderay 6 kv line 35. $,48,000 Osprey - Whitetail Tap 6 kv line (portion of double-circuit cost) 7.2 $,566,000 Couderay 6 kv Substation $3,650,000 Doughty Road - Doughty Road Tap 6 kv Line.4 $458,000 Total $28,752,000 While Option 3 proposes a configuration that is geographically diverse from the other alternatives, it is more than twice the cost of Option and connects to a source that is not as strong as Stone Lake Substation. The 345 kv line termination provided at Stone Lake Substation makes it a very attractive source for system support in the area. In addition to being the most expensive alternative presented, Option 3 also does not capture the opportunity to rebuild the 6 kv line Stone Lake and Couderay Substations. This line is currently in acceptable condition but sometime in the near future it will likely be in need of significant maintenance repairs. Options and 2 both afford the opportunity to rebuild this line and allow it to continue reliably serving load in the area in the years to come. For the reasons addressed above, and in consideration of the superior reliability benefits and cost savings brought by Option, it is Xcel Energy s recommendation that Option be pursued as the preferred alternative, with Options 2 and/or 3 presented as possible route and configuration alternatives. Xcel Energy, Inc. ii 4/23/2008

25 Appendix B Route and Configuration Alternative One-Lines Farmers Inn Functional Diagram Options & 2 -Option involves 6 and 6 kv lines being constructed on separate ROW -Option 2 involves 6 and 6 kv lines being double-circuited between Sand Lake and Couderay To Arrowhead To Hayward and Farmers Inn Stone Lake 0. mi To Washco Stone Lake Pump 2.5 mi Sand Lake 6.2 mi Edgewater Pump.3 mi.3 mi Couderay 7. mi To Gardner Park.5 mi To Park Falls To Prentice N Key 345 kv 6 kv 5 kv 6 kv Trails End Big Falls 8.7 mi 7.2 mi 0.0 mi White Tail Osprey To Sheldon Xcel Energy, Inc. iii 4/23/2008

26 Appendix B Farmers Inn Functional Diagram Option 3 -Whitetail Big Falls Osprey is double-circuit 6/6 kv To Arrowhead To Minong To Hayward and Farmers Inn Stone Lake 0. mi To Washco Stone Lake Pump 2.5 mi Sand Lake 6.2 mi Edgewater Pump.3 mi.3 mi Couderay 7. mi To Gardner Park.5 mi To Park Falls To Prentice N Key 345 kv 6 kv 5 kv 6 kv Trails End Big Falls 7.2 mi 0.0 mi 8.7 mi White Tail Osprey To Sheldon Xcel Energy, Inc. iv 4/23/2008

27 Appendix C Power Flow Contingency File Xcel Energy, Inc. v 4/23/2008

28 Appendix C SINGLE BRANCH IN SYSTEM ATC_con SINGLE TIE FROM SYSTEM ATC_con CONTINGENCY 'JRN' COM TRIP STINSON- LAKESIDE 5 KV LINE 6684 TO BUS 6632 CONTINGENCY 'JRN2' COM TRIP GINGLES- ASHLAND 6 KV LINE 6066 TO BUS 6040 CONTINGENCY 'JRN3' COM TRIP BAYFRONT- GINGLES 6 KV LINE 6025 TO BUS CONTINGENCY 'JRN4' COM TRIP GINGLES- HURLEY 5 KV LINE TO BUS 6028 CONTINGENCY 'JRN5' COM TRIP IRONWOOD- HURLEY 5 KV LINE 6028 TO BUS CONTINGENCY 'JRN6' COM TRIP IRONWOOD- PARK FALLS 5 LINE TO BUS 6028 CONTINGENCY 'JRN7A' COM TRIP STONE LAKE- FARMERS INN 6 KV LINE 6020 TO BUS 6023 CONTINGENCY 'JRN7B' COM TRIP FARMERS INN-GINGLES 6 KV LINE 6023 TO BUS 6024 CONTINGENCY 'JRN7AB' COM TRIP STONE LAKE- FARMERS INN-GINGLES 6 KV LINE 6020 TO BUS TO BUS 6024 CONTINGENCY 'JRN8' COM TRIP STONE LAKE- WASHCO 6 KV LINE 6020 TO BUS 656 CONTINGENCY 'JRN' COM TRIP OSPREY- SHELDON PUMP 5 KV LINE 6027 TO BUS 6026 CONTINGENCY 'JRN0' COM TRIP SHELDON PUMP-HOLCOMBE 5 KV LINE 6026 TO BUS CONTINGENCY 'JRN' COM TRIP HOLCOMBE- CORNELL 5 KV LINE TO BUS CONTINGENCY 'JRN2' COM TRIP STONE LAKE- STONE LAKE PUMP 6 KV LINE TO BUS 6205 CONTINGENCY 'JRN3' COM TRIP WHITE TAIL- OSPREY 6 KV LINE 62 TO BUS CONTINGENCY 'JRN4' COM TRIP STINSON PHASE SHIFTER 6683 TO BUS 6684 CONTINGENCY 'JRN5' COM TRIP WESTON UNIT TO BUS 3676 CONTINGENCY 'JRN6' COM TRIP OAK CREEK UNIT 3367 TO BUS 338 CONTINGENCY 'JRN7' COM TRIP KEWAUNEE UNIT 363 TO BUS 3630 CONTINGENCY 'JRN8' COM TRIP COLUMBIA UNIT 352 TO BUS 357 CONTINGENCY 'JRN' COM TRIP PRESQUE ISLE UNIT TO BUS 358 CONTINGENCY 'JRN20' COM TRIP PLLIAM UNIT TO BUS 304 CONTINGENCY 'JRN2' COM TRIP ARPIN-EAU CLAIRE 345 KV LINE TO BUS 3244 CONTINGENCY ' NSP 825 ' COM TRIP NOBLES CO - LAKEFIELD JC 345 KV LINE COM TRIP BREWSTER - ELK 6 KV LINE (4 MILE DOUBLE CKT) TO BUS TO BUS TO BUS CONTINGENCY ' NSP 825 2' COM TRIP NOBLES CO - LAKEFIELD JC 345 KV LINE COM TRIP LAKEFIELD JC - TRIBOJI 6 KV LINE (6 MILE DOUBLE CKT) TO BUS TO BUS CONTINGENCY ' NSP 825 3' COM TRIP SPLIT ROCK - NOBLES CO 345 KV LINE COM TRIP ELK - MAGNOLIA 6 KV LINE (8 MILE DOUBLE CKT) 6026 TO BUS TO BUS CONTINGENCY ' NSP 825 4' COM TRIP SPLIT ROCK - NOBLE CO 345 KV COM TRIP SPLIT ROCK - SIOUX CITY 345 KV (5 MILES DOUBLE CKT) 6026 TO BUS TO BUS 6026 CONTINGENCY 'NSP MANKATO' COM TRIP EASTWOOD - SUMMIT 5 KV LINE COM TRIP EASTWOOD - LOON TAP 5 KV LINE TO BUS CKT TO BUS CKT CONTINGENCY 'NSP WESTGATE' COM TRIP WESTGATE - EDEN PRAIRIE 5 KV CKT COM TRIP WESTGATE - EDEN PRAIRIE 5 KV CKT TO BUS CKT TO BUS CKT 2 CONTINGENCY 'NSP SPS 2' COM TRIP WILMARTH - BLUE LAKE 345 KV CKT COM TRIP MEC STEAM TURBINE 6008 TO BUS 602 CKT REMOVE MACHINE FROM BUS CONTINGENCY 'NSP SPS 3' COM TRIP LAKEFIELD JC - LGS 345 KV LINE Xcel Energy, Inc. vi 4/23/2008

29 Appendix C COM TRIP LAKEFIELD JC - NOBLES CO 345 KV LINE TO BUS TO BUS CONTINGENCY 'NSP- GRE SPS 3-4 COMBO'\par COM TRIP 345 KV LINE FROM LGS - FIELDON / WILMARTH\par COM TRIP LAKEFIELD JC - NOBLES CO 345 KV LINE\par COM TRIP TRIMONT WIND GENERATION\par COM TRIP LAKEFIELD GENERATING STATION\par 6033 TO BUS 60364\par TO BUS 60286\par REMOVE MACHINE FROM BUS 6300\par REMOVE MACHINE FROM BUS 630\par REMOVE MACHINE 2 FROM BUS 6302\par REMOVE MACHINE 3 FROM BUS 6303\par REMOVE MACHINE 4 FROM BUS 6304\par REMOVE MACHINE 5 FROM BUS 6305\par REMOVE MACHINE 6 FROM BUS 6306\par CONTINGENCY 'WILMARTH - BLUELAKE' 6008 TO BUS TO BUS 6003 CKT / MEC 600 TO BUS CKT / MEC CONTINGENCY 'WILMARTH - BLUELAKE 6008 TO BUS TO BUS TO BUS 6003 CKT / MEC 600 TO BUS CKT / MEC CONTINGENCY 'WILMARTH - LGS 6033 TO BUS TO BUS 630 CKT / LGS TO BUS 6302 CKT / LGS TO BUS 6303 CKT / LGS 5-6 CONTINGENCY 'WILMARTH - LGS TO BUS TO BUS 630 CKT / LGS TO BUS 6302 CKT / LGS TO BUS 6303 CKT / LGS 5-6 CONTINGENCY 'WILMARTH - LGS TO BUS TO BUS 630 CKT / LGS TO BUS 6302 CKT / LGS TO BUS 6303 CKT / LGS 5-6 CONTINGENCY 'FOX LAKE' TO BUS TO BUS CONTINGENCY 'FOX LAKE2' TO BUS TO BUS COM ' START DAKOTA AREA CONTINGENCIES' COM 'NSP - Defined as multi-circuit' COM 'SPLIT ROCK-WHITE & SPLIT ROCK-SIOUX CITY 345' COM 'A SPLT RK3-SPLTRTA3 CKT OPENS C tower, B MTL' COM 'B SPLTRTA3-WHITE 3 CKT OPENS A MTL' COM 'C SPLT RK3-SPLTRTB3 CKT OPENS A tower, D MTL' COM 'D SPLTRTB3-SIOUXCY3 CKT OPENS C MTL' CONTINGENCY 'NSP - ' 6026 TO BUS 6030 CKT 6030 TO BUS CKT 6026 TO BUS 603 CKT 603 TO BUS CKT COM 'NSP - 2 DEFINED AS MULTI-CIRCUIT' COM 'SPLIT ROCK- CHERRY CREEK/WEST SIOUX FALLS' COM 'A SPLT RK7-CHERRYC7 CKT OPENS B TOWER' COM 'B SPLT RK7-WSX FLS7 CKT OPENS A TOWER' ' CONTINGENCY 'NSP - 2' 602 TO BUS 607 CKT 602 TO BUS 6032 CKT COM 'NSP - 3 DEFINED AS MULTI-CIRCUIT' COM 'MAPLE RIVER- SHEYENE/WAHPETON' COM 'A MAPLE R4-SHEYNNE4 CKT OPENS B TOWER' COM 'B MAPLE R4-WAHPETN4 CKT OPENS A TOWER' CONTINGENCY 'NSP - 3' TO BUS 6033 CKT TO BUS 6332 CKT COM 'NSP - 4 DEFINED AS MULTI-CIRCUIT' COM 'PRAIRIE-NODIC' COM 'A PRAIRIE7-NORDIC 7 CKT OPENS B TOWER' COM 'B PRAIRIE7-NORDIC 7 CKT 2 OPENS A TOWER' CONTINGENCY 'NSP - 4' 6672 TO BUS 604 CKT 6672 TO BUS 604 CKT 2 COM '535 Defined as multi-circuit tower and mtl' COM 'A SHEYNNE7-CASS CO7 CKT OPENS B,C tower only' COM 'B MODEROW7-SHEYNNE7 CKT OPENS A,C, also mtl' COM 'C MODEROW7-CASS CO7 CKT OPENS A,B, also mtl' COM '** Defined as multiterminal' COM 'E CASS CO7-REDRIVR7 CKT OPENS D,F' COM 'F CASS CO7-MODEROW7 CKT OPENS D,E' COM 'G MODEROW7-SHEYNNE7 CKT OPENS E,F,' CONTINGENCY '535 ' COM 'Tower contingency of Sheyenne-Cass Co.,Moderow-Sheyenne' COM 'and Moderow-Cass Co. 5kV lines. With combination mtl' COM 'portion.' 6034 TO BUS 6035 CKT 2 Xcel Energy, Inc. vii 4/23/2008

30 Appendix C 6676 TO BUS 6034 CKT 6676 TO BUS 6035 CKT COM 'Also trips the following MTL because of C' 6035 TO BUS 6037 CKT CONTINGENCY '535 2' COM ' Multi-terminal only' 6035 TO BUS 6037 CKT 6035 TO BUS 6676 CKT 6676 TO BUS 6034 CKT COM ' CROSS TRIP FOR TIOGA-LOGAN 230KV LINE OF THE TIOGA' COM ' 5/230 TRANSFORMER. NOT VALID UNTIL THE B0T FLOW' COM ' TOWARD THE SOUTH IS OVER 00MW' - CONTINGENCY ' ' 6704 TO BUS 6708 CKT 6704 TO BUS CKT COM '00 OTP WAPA Defined as multi-terminal, wapa/otp' COM 'A DEVILSL7-DEVIL J7 CKT OPENS B C D E F G H I J' COM 'B DEVIL J7-DEVIL S7 CKT OPENS A C D E F G H I J' COM 'C DEVIL J7-DEVILSE7 CKT OPENS A B D E F G H I J' COM 'D DEVILSE7-RAMSEY 7 CKT OPENS A B C E F G H I J' COM 'E DEVILSE7-SWEETWA7 CKT OPENS A B C D F G H I J' COM 'F SWEETWA7-LOMA JT7 CKT OPENS A B C D E G H I J' COM 'G LOMA JT7-LANGDON7 CKT OPENS A B C D E F H I J' COM 'H LANGDON7-LANDGONT CKT OPENS A B C D E F G I J' COM 'I LANGDONT-LANGDON CKT OPENS A B C D E F G H J' COM 'J LANDGONT-LANGDON8 CKT OPENS A B C D E F G H I' - CONTINGENCY '00 ' 6643 TO BUS CKT TO BUS CKT TO BUS CKT TO BUS CKT TO BUS CKT TO BUS CKT TO BUS 6670 CKT 6670 TO BUS CKT TO BUS 6364 CKT TO BUS CKT COM '05 Defined as multi-circuit, tower' COM 'A BISMARK4-GARRISN4 CKT OPENS B or C tower' COM 'B BISMARK4-WASHBRN4 CKT OPENS A tower, MTL ' COM 'C GARRISN4-LELANDO4 CKT OPENS A tower' COM '** Defined as multiterminal' COM 'D BISMARK4-WASHBRN4 CKT OPENS E MTL' COM 'E WASHBRN4-LELANDO4 CKT OPENS D MTL' CONTINGENCY '05 ' COM 'Tower with multiterminal' TO BUS 6644 CKT TO BUS CKT COM 'Also trips the following because of B' TO BUS 6706 CKT CONTINGENCY '05 2' COM 'Tower only' TO BUS 6644 CKT 6644 TO BUS 6706 CKT CONTINGENCY '05 3' COM 'Multi-terminal only' TO BUS CKT TO BUS 6706 CKT COM '0 Defined as multi-circuit, tower' COM 'A BLAIR 4-WATERTN4 CKT OPENS B tower' COM 'B WATERTN4-GRANITF4 CKT OPENS A or C tower' COM 'C BLAIR 4-GRANITF4 CKT OPENS B tower' CONTINGENCY '0 ' TO BUS CKT TO BUS CKT CONTINGENCY '0 2' TO BUS CKT TO BUS CKT COM ' WAPA Defined as multi-terminal, Interregional' COM 'ASH STREET TAP' COM 'A ASHTAP 7-ASH ST 7 CKT OPENS B C' COM 'B ASHTAP 7-OAHE 7 CKT OPENS A B' COM 'C ASHTAP 7-PIERRE 7 CKT OPENS A C' CONTINGENCY ' ' TO BUS 6660 CKT TO BUS CKT TO BUS 6648 CKT COM '2 WAPA Defined as multi-terminal, Interregional' COM 'EVANS STREET TAP' COM 'A EVANSST7-ASH ST 7 CKT OPENS A B' COM 'B EVANSST7-PIERRE 7 CKT OPENS B C' CONTINGENCY '2 ' TO BUS 6660 CKT TO BUS 6648 CKT COM '3 WAPA Defined as multi-terminal, Interregional' COM 'NWPS huronwestpark-redfield' COM 'A BTAP WP7-HURON 7 CKT OPENS B C' COM 'B BTAP WP7-REDFLD 7 CKT OPENS A C' COM 'C BTAP WP7-HURONWP7 CKT OPENS A B' Xcel Energy, Inc. viii 4/23/2008

31 Appendix C CONTINGENCY '3' 674 TO BUS 6655 CKT 674 TO BUS CKT 674 TO BUS CKT COM '4 WAPA Defined as multi-terminal, Interregional' COM 'Little Missioui Tap' COM 'A BOWMAN 4-LTLMISS4 CKT OPENS B C' COM 'B LTLMISS4-BAKER 7 CKT OPENS A B' COM 'C LTLMISS4-LTLMISS7 CKT OPENS A C' CONTINGENCY '4' 6730 TO BUS CKT TO BUS CKT TO BUS CKT COM '20 Defined as multi-circuit, tower' COM 'A BROOKNG7-WATERTN7 CKT OPENS B tower' COM 'B WATERTN3-WHITE 3 CKT OPENS A tower' CONTINGENCY '20 ' TO BUS 6653 CKT 6652 TO BUS CKT COM '08 Defined as multi-circuit, tower' COM 'A FTTHOMP4-FTRANDL4 OPENS B or C tower' COM 'B FTTHOMP4-LAKPLAT4 OPENS A tower' COM 'C FTRANDL4-LAKPLAT4 OPENS A tower' CONTINGENCY '08 ' TO BUS 6650 CKT TO BUS 6656 CKT 6650 TO BUS 6656 CKT COM '30 Defined as multi-circuit, tower' COM 'A FTTHOMP4-SIOUXFL4 OPENS BorCorD tower' COM 'B FTTHOMP4-STORLA 4 OPENS A tower, MTL' COM 'C HANLON 4-STORLA 4 OPENS A tower, MTL' COM 'D HANLON 4-SIOUXFL4 OPENS A tower' COM '** Defined as multiterminal, MTL' COM 'E FTTHOMP4-STORLA 4 OPENS F G' COM 'F HANLON 4-STORLA 4 OPENS E G' COM 'G STORLA 4-STORLA 7 VLD SGL' CONTINGENCY '30 ' TO BUS CKT TO BUS 6722 CKT COM 'Also trips the following because of B mtl' TO BUS 6722 CKT 6653 TO BUS 6722 CKT 6722 TO BUS 6723 CKT CONTINGENCY '30 2' TO BUS CKT 6653 TO BUS CKT COM '40 Defined as multi-circuit, tower' COM 'A FTTHOMP4-HURON 4 OPENS B tower' COM 'B FTTHOMP4-HURON 4 2 OPENS A tower' CONTINGENCY '40 ' TO BUS 6654 CKT TO BUS 6654 CKT 2 COM '50 Defined as multi-circuit, tower' COM 'A FTTHOMP4-OAHE 4 OPENS B tower' COM 'B FTTHOMP4-OAHE 4 2 OPENS A tower' CONTINGENCY '50 ' TO BUS 665 CKT TO BUS 665 CKT 2 COM '5 Defined as multi-circuit' COM 'A FTTHOMP4-OAHE 4 3 OPENS B tower' COM 'B FTTHOMP4-OAHE 4 4 OPENS A tower' CONTINGENCY '5 ' TO BUS 665 CKT TO BUS 665 CKT 4 COM '60 Defined as multi-circuit, tower' COM 'A FTRANDL4-SIOUXCY4 OPENS BorCorD tower' COM 'B FTRANDL4-UTICAJC4 OPENS A tower, MTL' COM 'C UTICAJC4-RASMUSN4 OPENS A tower, MTL' COM 'D RASMUSN4-SIOUXCY4 OPENS A tower' COM '** Defined as multiterminal' COM 'E FTRANDL4-UTICAJC4 OPENS F G' COM 'F UTICAJC4-VFODNES4 OPENS E G' COM 'G UTICAJC4-RASMUSN4 OPENS E F' CONTINGENCY '60 ' 6650 TO BUS CKT 6650 TO BUS CKT COM 'Also trips the following because of B' TO BUS CKT 6638 TO BUS CKT CONTINGENCY '60 2' 6650 TO BUS CKT TO BUS CKT CONTINGENCY '60 3' 6650 TO BUS CKT 6638 TO BUS CKT TO BUS CKT COM '70 Defined as multi-circuit, tower' COM 'A HURON 4-WATERTN4 OPENS B tower' COM 'B HURON 4-WATERTN4 2 OPENS A tower' CONTINGENCY '70 ' 6654 TO BUS CKT 6654 TO BUS CKT 2 Xcel Energy, Inc. ix 4/23/2008

32 Appendix C COM '80 GRE Defined as multi-terminal tower' COM 'multi-terminal trips A B and C' COM 'A COAL CR4-COAL TP4 OPENS B, C' COM 'B COAL TP4-STANTON4 OPENS A, C' COM 'C COAL TP4-MCHENRY4 OPENS A, B' COM 'A and B multi-circuit tower with portions of D and operating response' COM 'D COAL CR4-STANTON4' CONTINGENCY '80 ' COM 'mtl outage portion' 6304 TO BUS CKT TO BUS 6304 CKT TO BUS CKT CONTINGENCY '80 2' COM 'Common tower outage with mtl portion' 6304 TO BUS CKT TO BUS 6304 CKT TO BUS CKT 6304 TO BUS 6304 CKT COM '0 Defined as multiterminal' COM 'A FARGO 7-CLDONIA7 CKT OPENS B C D E F' COM 'B CALEDON7-EGF IND7 CKT OPENS C C D E F' COM 'C EGF IND7-GRNDFKS7 CKT OPENS A B D E F' COM 'D CALEDONT-CALEDON7 CKT OPENS A B C E F' COM 'E CALEDONT-CALEDON CKT OPENS A B C D F' COM 'F CALEDONT-CALEDON8 CKT OPENS A B C D E' - CONTINGENCY '0 ' TO BUS CKT TO BUS CKT TO BUS CKT TO BUS CKT TO BUS CKT TO BUS CKT COM '200 Defined as multiterminal' COM 'A GRNDFKS4-PICKERT4 CKT OPENS B C D E' COM 'B JAMESTN4-PICKERT4 CKT OPENS A C D E' COM 'C PICKERT4-PICKERTY CKT OPENS A B D E' COM 'D PICKERTY-PICKERT8 CKT OPENS A B C E' COM 'E PICKERTY-PICKERT CKT OPENS A B C D' - CONTINGENCY '200 ' TO BUS 6675 CKT TO BUS 6675 CKT 6675 TO BUS 6388 CKT 6388 TO BUS 6623 CKT 6388 TO BUS 6367 CKT COM '20 Defined as COM 'A NUNDRWD4-PHILTAP4 CKT OPENS B C' COM 'B PHILTAP4-OAHE 4 CKT OPENS A C' COM 'C PHILIP 4-PHILTAP4 CKT OPENS A B' - CONTINGENCY '20 ' TO BUS CKT TO BUS 665 CKT TO BUS CKT COM '220 Defined as COM 'A BUFFALO3-JAMESTN3 OPENS B C D E F G H I J K' COM 'B MAPLE R3-BUFFALO3 OPENS A C D E F G H I J K' COM 'C BUFFALO3-BUFFALOY OPENS A B D E F G H I J K' COM 'D BUFFALOY-BUFFALO7 OPENS A B C E F G H I J K' COM 'E BUFFALOY-BUFFALO OPENS A B C D F G H I J K' COM 'F MAPLE R3-MAPLERY OPENS A B C D E G H I J K' COM 'G MAPLERY-MAPLE R4 OPENS A B C D E F H I J K' COM 'H MAPLERY-MAPLER OPENS A B C D E F G I J K' COM 'I MAPLE R3-MAPLER2Y OPENS A B C D E F G H J K' COM 'J MAPLER2Y-MAPLE R4 OPENS A B C D E F G H I K' COM 'K MAPLER2Y-MAPLER2 OPENS A B C D E F G H I J' -- CONTINGENCY '220 ' TO BUS 6336 CKT 6672 TO BUS CKT TO BUS 638 CKT 638 TO BUS CKT 638 TO BUS 6358 CKT 6672 TO BUS 638 CKT 638 TO BUS CKT 638 TO BUS 6335 CKT 630 TO BUS CKT 6672 TO BUS 630 CKT 630 TO BUS CKT COM '230 OTP Defined as COM 'A FORMAN 4-HANKSON4 OPENS B C D E F G H I J K L M' COM 'B FORMAN 4-OAKS 4 OPENS A C D E F G H I J K L M' COM 'C ELLL4-OAKS 4 OPENS A B D E F G H I J K L M' COM 'D OAKS 4-OAKS OPENS A B C E F G H I J K L M' COM 'E FORMAN 4-FORMAN Y OPENS A B C D F G H I J K L M' COM 'F FORMAN Y-FORMAN OPENS A B C D E G H I J K L M' COM 'G FORMAN Y-FORMAN 7 OPENS A B C D E F H I J K L M' -- CONTINGENCY '230 ' COM 'Trip of the 230kV line sections and Forman' Xcel Energy, Inc. x 4/23/2008

33 Appendix C TO BUS CKT TO BUS CKT TO BUS CKT TO BUS 6362 CKT TO BUS 633 CKT 633 TO BUS 6363 CKT 633 TO BUS CKT COM '250 GRE Defined as multi-terminal line, upa/otp' COM 'A PRAIRIE4-RAMSEY 4 VLD SGL' COM 'B BALTA 4-RAMSEY 4 VLD SGL' COM 'C RAMSEY 7-RAMSEY 4 OPENS A B' CONTINGENCY '250 ' COM 'Transformer fault at Ramsey, mtl' TO BUS CKT TO BUS CKT TO BUS CKT COM '260 GRE Defined as multi-terminal line' COM 'A MCHENRY4-BALTA 4 OPENS B C' COM 'B COAL TP4-MCHENRY4 OPENS ' COM 'C MCHENRY4-MCHENRY7 OPENS A B ' CONTINGENCY '260 ' TO BUS CKT TO BUS CKT TO BUS 6040 CKT COM ' DAKOTA AREA CONTINGENCIES' CONTINGENCY 'test' 8 TO BUS CKT 2 COM ' START NEBRASKA AREA CONTINGENCIES' COM '380 Defined as multi-terminal, Interregional' COM 'A COOPER 3-7FAIRPT OPENS B' COM 'B FAIRPT -ST JOE 3 OPENS A' - CONTINGENCY '380 ' TO BUS 603 CKT 603 TO BUS 533 CKT COM '300 Defined as multiterminal, or multi-circuit tower RW' COM 'A VICTRYH4-STEGALL4 CKT OPENS B C D' COM 'B VICTRYH4-VICTHL Y CKT OPENS A C D' COM 'C VICTRYH7-VICTHL Y CKT OPENS A B D' COM 'D VICTR0G-VICTHL Y CKT OPENS A B C' - CONTINGENCY '300 ' 6500 TO BUS CKT 6500 TO BUS CKT TO BUS CKT TO BUS CKT COM '30 Defined as multi-circuit, tower RW' COM 'A GENTLMN3-REDWILO3 CKT OPENS B' COM 'B GENTLMN3-SWEET W3 CKT 2 OPENS A' -- CONTINGENCY '30 ' 6483 TO BUS 6443 CKT 6483 TO BUS 6484 CKT 2 COM '320 Defined as multi-circuit, tower and RW' COM 'A GENTLMN4-N.PLATT4 2 OPENS B tower' COM 'B GENTLMN4-N.PLATT4 3 OPENS A tower' COM 'Simultaneous outage of A and B will OPENS C' COM 'C C.CREEK4-N.PLATT4 OPENS BorA RW' -- CONTINGENCY '320 ' TO BUS 640 CKT TO BUS 640 CKT TO BUS 640 CKT COM '330 Defined as multi-circuit, RW' COM 'A SWEET W3-GR ISLD3 OPENS B RW' COM 'B FTTHOMP3-GR ISLD3 OPENS A RW' CONTINGENCY '330 ' 6484 TO BUS 6657 CKT TO BUS 6657 CKT COM '340 Defined as multi-circuit, RW' COM 'A GR ISLD4-HASTING4 OPENS B C D RW, MTL' COM 'B SUB-D 7-DONIPHN7 OPENS A C D RW, MTL' COM 'C DONIPHN7-DONIPHN OPENS A B D' COM 'D DONIPHN7-PROSSER7 OPENS A B C' -- CONTINGENCY '340 ' 6483 TO BUS CKT 6527 TO BUS CKT TO BUS CKT TO BUS 644 CKT COM '350 Defined as COM 'A GR ISLD4-HASTING4 OPENS B C' COM 'B HASTING4-HASTNG Y OPENS A C' COM 'C HASTING7-HASTNG Y OPENS A B' - CONTINGENCY '350 ' 6483 TO BUS CKT TO BUS CKT TO BUS CKT COM '360 Defined as COM 'A CANADAY4-C.CREEK4 OPENS B C' COM 'B CANADAY4-CANADAYY OPENS A C' COM 'C CANADAY7-CANADAYY OPENS A B' - Xcel Energy, Inc. xi 4/23/2008