Interoffice Memorandum System Planning MEMO: DATE: TO: FROM: SUBJECT: SP-2013-07 February 15, 2012 Scott Waples Richard Maguire IRP Generation Study - Benewah to Boulder 230kV (BB-IRP) Introduction This study addresses a request from Avista’s Power Supply Department for the 2013 IRP regarding new generation on the Benewah - Boulder 230 kV Transmission Line at one of two capacity levels: 150 MW 300 MW The study presents information and discussion on the follow topics: Power flow impact to the transmission system Transmission system upgrades necessary to deliver requested generation Study Assumptions and Methodology The five year planning horizon Avista planning cases, as documented in SP-2011-03 – 2011 Planning Cases Summary Data, are modified with the following projects and adjustments prior to system analysis: LGIR #35 project (200 MW at Thornton 230 kV Substation) LGIR #36 project (105 MW at Thornton 230 kV Substation) BB-IRP topology: o Benewah – Boulder 230kV Transmission Line tapped 13.1 electrical miles North of Benewah 230 kV Substation o Generic generator installed on new BB-IRP 230 kV bus The following cases are used during this study: Avista Heavy Summer High Hydro (“HSHH”) case: AVA-11hs2a-12BA2085 o Table 1 shows power flows for this case Avista Heavy Summer Low Hydro (“HSLH”) case: AVA-11hs2a-12BA2085-LH o Table 2 shows power flows for this case Avista Light Summer with High West of Hatwai (High Transfers or “HT”)Flows: AVA11ls1ae-12BA1251-WOH4277 o Table 3 shows power flows for this case with BB-IRP output = 300 MW Benewah – Boulder 2013 IRP Study Table 1: Regional Power Flows for Heavy Summer Case Western Montana Hydro Noxon Rapids (562MW) Cabinet Gorge (265MW) Libby (605MW) Hungry Horse (430MW) 1098.1 MW 399.4 MW 184.7 MW 324.0 MW 190.0 MW West of Hatwai (Path 6) Lolo-Oxbow 230kV Dry Creek-Walla Walla 230kV 951.8 MW 296.0 MW 184.1 MW West of Cabinet Montana-Northwest (Path 8) 1581.7 MW 979.0 MW Colstrip Total Colstrip 1 (330MW) Colstrip 2 (330MW) Colstrip 3 (823MW) Colstrip 4 (823MW) 330.0 MW 330.0 MW 795.5 MW 804.9 MW Idaho-Northwest (Path 14) -585.4 MW Midpoint-Summer Lake (Path 75) -48.9 MW Idaho-Montana (Path 18) -296.3 MW Rathdrum Thermal (175MW) Lancaster Thermal (270MW) Spokane River Hydro Boundary Hydro (1040MW) 0.0 MW 249.0 MW 88.3 MW 635.0 MW Lower Snake/N.F. Clearwater Dworshak (458MW) Lower Granite (930MW) Little Goose (930MW) Lower Monumental (930MW) Coulee Generation Coulee 500 kV Coulee 230 kV 316.0 MW 554.2 MW 555.5 MW 531.5 MW 2308.5 MW 1292.7 MW South of Boundary North of John Day (Path 73) TOT 4A (Path 37) Miles City DC 582.9 MW 7034.7 MW 407.0 MW 142.0 MW Path C (Path 20) Borah West (Path 17) Bridger West (Path 19) Pacific AC Intertie (Path 66) Pacific DC Intertie (Path 65) 118.7 MW 837.4 MW 2191.6 MW 4430.9 MW 2980.0 MW Northwest Load Idaho Load Montana Load Avista Native Load Avista Balancing Area Load Clearwater Load 25129.6 MW 3702.5 MW 1836.8 MW -1594.3 MW 1885.6 MW 58.3 MW Table 2: Regional Power Flows for Light Summer Case Western Montana Hydro Noxon Rapids (562MW) Cabinet Gorge (265MW) Libby (605MW) Hungry Horse (430MW) 627.1 MW 138.8 MW 82.3 MW 216.0 MW 190.0 MW West of Hatwai (Path 6) Lolo-Oxbow 230kV Dry Creek-Walla Walla 230kV 120.3 MW 277.0 MW 159.6 MW West of Cabinet Montana-Northwest (Path 8) 1110.7 MW 970.1 MW Colstrip Total Colstrip 1 (330MW) Colstrip 2 (330MW) Colstrip 3 (823MW) Colstrip 4 (823MW) 330.0 MW 330.0 MW 764.2 MW 776.0 MW Idaho-Northwest (Path 14) -585.9 MW Midpoint-Summer Lake (Path 75) -76.0 MW Idaho-Montana (Path 18) -274.8 MW Rathdrum Thermal (175MW) Lancaster Thermal (270MW) Spokane River Hydro Boundary Hydro (1040MW) 0.0 MW 249.0 MW 58.1 MW 310.0 MW Lower Snake/N.F. Clearwater Dworshak (458MW) Lower Granite (930MW) Little Goose (930MW) Lower Monumental (930MW) Coulee Generation Coulee 500 kV Coulee 230 kV 316.0 MW 554.2 MW 555.5 MW 531.5 MW 3066.4 MW 1292.7 MW South of Boundary North of John Day (Path 73) TOT 4A (Path 37) Miles City DC 299.4 MW 6931.9 MW 399.6 MW 142.0 MW Path C (Path 20) Borah West (Path 17) Bridger West (Path 19) Pacific AC Intertie (Path 66) Pacific DC Intertie (Path 65) 133.4 MW 830.6 MW 2188.8 MW 4222.6 MW 2980.0 MW Northwest Load Idaho Load Montana Load Avista Native Load Avista Balancing Area Load Clearwater Load 25129.6 MW 3702.5 MW 1836.8 MW -1594.3 MW 1874.1 MW 75.8 MW Benewah – Boulder 2013 IRP Study Table 3: Regional Power Flows for High Transfer Case Western Montana Hydro Noxon Rapids (562MW) Cabinet Gorge (265MW) Libby (605MW) Hungry Horse (430MW) 1548.0 MW 432.2 MW 195.8 MW 540.0 MW 380.0 MW West of Hatwai (Path 6) Lolo-Oxbow 230kV Dry Creek-Walla Walla 230kV 4251.2 MW 140.1 MW 189.5 MW West of Cabinet Montana-Northwest (Path 8) 3204.5 MW 2040.8 MW Colstrip Total Colstrip 1 (330MW) Colstrip 2 (330MW) Colstrip 3 (823MW) Colstrip 4 (823MW) 330.0 MW 330.0 MW 777.6 MW 782.9 MW Idaho-Northwest (Path 14) 741.0 MW Midpoint-Summer Lake (Path 75) 831.7 MW Idaho-Montana (Path 18) -198.3 MW Rathdrum Thermal (175MW) Lancaster Thermal (270MW) Spokane River Hydro Boundary Hydro (1040MW) 116.4 MW 118.1 MW 152.4 MW 975.0 MW Lower Snake/N.F. Clearwater Dworshak (458MW) Lower Granite (930MW) Little Goose (930MW) Lower Monumental (930MW) Coulee Generation Coulee 500 kV Coulee 230 kV 168.2 MW 0.0 MW 141.8 MW 310.0 MW 825.7 MW 125.0 MW South of Boundary North of John Day (Path 73) TOT 4A (Path 37) Miles City DC 961.8 MW 4775.0 MW 448.4 MW 200.0 MW Path C (Path 20) Borah West (Path 17) Bridger West (Path 19) Pacific AC Intertie (Path 66) Pacific DC Intertie (Path 65) 528.7 MW 1570.2 MW 2098.0 MW 3136.7 MW 1999.9 MW Northwest Load Idaho Load Montana Load Avista Native Load Avista Balancing Area Load Clearwater Load 17796.4 MW 2326.0 MW 1339.5 MW -837.0 MW 680.3 MW 71.1 MW Benewah – Boulder 2013 IRP Study Study Results Thermal Performance during Category A conditions 1 This preliminary study indicates the Avista Transmission System has adequate capacity to integrate 300 MW at the proposed interconnection point during Category A all lines in service conditions. Thermal Performance during Category B and Category C conditions Table 4 shows preliminary results of a study using PowerWorld Simulator’s Available Transfer Capability (ATC) tool for generation injections at BB-IRP. This tool generates a list of facility thermal violations (From To) that arise under contingency conditions for incremental increases in generation output (BB WM). When the results for each case under study are collected and analyzed together with results from standard contingency analysis studies, this tool provides an idea of what facilities overload for rising levels of generation output. As the table shows, there are six facilities that come into violation for a requested BB-IRP output of 150 MW, and there are an additional five facilities that come into violation for a requested BB-IRP output of 300 MW. Table 4: Incremental generation analysis for BB-IRP IRP request 2 Case MW Output Limiting Contingency From Name To Name HSLH 27.11 BF: A470 Westside 115 kV, College & Walnut-Westside GLENTAP NINTHCNT HSHH 28.2 BUS: Westside 115 kV POSTSTRT THIRHACH HT 84.08 N-1: Hatwai - Moscow 230 230 kV MOSCOW MOSCOWX HSLH 106.34 BUS: Westside 115 kV ROSSPARK THIRHACH HSHH 106.63 BF: A413 Westside 115 kV, Ninemile-Westside POSTSTRT THIRHACH HSHH 112.15 BF: A689 Ninth & Central South 115 kV, Ninth & Central-Otis Orchards POSTSTRT THIRHACH HSLH 116.64 N-2: Bell - Westside 230 kV & Coulee - Westside 230 kV GLENTAP NINTHCNT HSLH 117.24 BUS: Westside 230 kV GLENTAP NINTHCNT HSLH 123.43 BF: A370 Bell S1 & S2 230 kV BEACON N BEACON N HSHH 160.37 N-1: Shawnee - Thornton 230 kV MOSCOW MOSCOWX HSHH 164.3 N-1: North Lewiston - Shawnee 230 kV TERRVIEW NPULLMAN HSHH 173.34 BUS: North Lewiston 230 kV TERRVIEW NPULLMAN HSLH 184.24 BF: A413 Westside 115 kV, Ninemile-Westside ROSSPARK THIRHACH HT 206.31 N-2: Beacon - Boulder 230 kV & Beacon - Rathdrum 230 kV BOULDERE IRVIN HT 215.35 BF: R427 Beacon North & South 230 kV BOULDERE IRVIN HT 215.68 N-2: Beacon - Boulder 230 kV & Beacon - Rathdrum 230 kV IRVIN MILLWOOD HT 223.63 BF: R427 Beacon North & South 230 kV IRVIN MILLWOOD HSHH 253.83 N-2: Shawnee - Thornton 230 kV & Lind - Shawnee 115 kV MOSCOW MOSCOWX HT 269.19 N-2: Beacon - Boulder 230 kV & Beacon - Rathdrum 230 kV BOULDERW SPKINDPK HT 271.24 BUS: Hatwai 230 kV MOSCOWX MOSCOW HSLH 272.76 BUS: Hatwai 230 kV MOSCOWX MOSCOW HSLH 275.44 PSF: Ninth & Central South 115 kV BEACON S NINTHCNT HSHH 275.67 BUS: Westside 230 kV POSTSTRT THIRHACH HSHH 275.84 N-2: Bell - Westside 230 kV & Coulee - Westside 230 kV POSTSTRT THIRHACH HT 280.08 BF: R427 Beacon North & South 230 kV BOULDERW SPKINDPK HSLH 298.33 BUS: North Lewiston 230 kV HATWAI LOLO HT 300.27 N-2: Bell - Taft 500 kV and Bell - Lancaster 230 kV BOULDER BB-IRP 1 Contingency category descriptions can be found at: http://www.nerc.com/files/TPL-001-0.pdf 2 BF = Breaker Failure; PSF = Protection System Failure; N-X contingencies refer to ‘X’ transmission element outages Benewah – Boulder 2013 IRP Study Notes regarding thermal performance: Avista has planned projects that mitigate some of the above mentioned facility violations. However, some of the planned projects also result in new facility thermal violations during contingencies. Further study of planned projects and potential options will be necessary. Preliminary studies indicate some reduction in the above thermal violations when Projects #35 and #36 are removed from study, but the reduction in thermal violations is confined mainly to limiting facilities south of BB-IRP. Without Projects #35 and #36, significant power continues to flow north through the Boulder 230 kV substation and onto the local 115 kV Transmission System in the Spokane and Spokane Valley areas. Voltage Performance Preliminary studies show voltage issues of a nature that can be addressed with properly sited reactive support. Further detailed studies can be used to determine the exact amount and location of any reactive support necessary to mitigate facility voltage violations. Benewah – Boulder 2013 IRP Study Potential Solutions Options3 230 kV Switching station required for all options mentioned below: 4 position double bus double breaker ~ $4 M Option 1: Reconductor facilities brought into violation due to the requested generation 150 MW option would require: o $3.41 M of 115 kV upgrades 300 MW option would require an additional: o $1.9 M of 115 kV upgrades o $5.36 M of 230 kV upgrades Option 2: Complete currently planned projects and reconductor limiting facilities Currently Planned Projects: o Lancaster Interconnection o Spokane Valley Transmission Reinforcement o Moscow Transformer Replacement o Westside Transformer Replacement 150 MW option would require: o $2.4 M of 115 kV upgrades 300 MW option would require an additional: o $932 K of 115 kV upgrades o $5.36 M of 230 kV upgrades Conclusion This project is a feasible project based on the preliminary analysis performed. A summary of options and cost estimates is given in Table 3. Option 1 1 2 3 3 Maximum Output 150 MW 300 MW 150 MW 300 MW Total Cost ($000) $7,410 $14,670 $6,400 $12,690 All construction costs are in 2013-year dollars and based on engineering judgment alone with +/- 50% accuracy