North Oregon Coast Area Study Adam Lint
PAGE 2 North Oregon Coast System Overview - Clatsop Study Covers: Transmission Switching Stations (Clatsop District): Astoria Lewis and Clark 115 kv Distribution Substations (Clatsop District): Knappa Svensen Fern Hill Young s Bay Warrenton Seaside Cannon Beach Foreign Substations: Clatsop (BPA) Necanicum (WOEC)
PAGE 3 North Oregon Coast System Overview- Clatsop Transmission Source 230 kv Source from Clatsop Substation (BPA) via Lewis and Clark Switching Station 230 kv Source from Tillamook Substation (BPA) Weak 115 kv source Astoria Driscoll (BPA); Fed from Allston (BPA) Astoria Tillamook 115 kv Transmission Line (Sugarloaf Line) Three Terminal Line (Astoria Lewis and Clark Tillamook) Serves PacifiCorp Substations Warrenton, Seaside, and Cannon Beach Serves Tillamook PUD substations Nehalem, Mohler, and Garibaldi Serves Western Oregon Electric Substation Necanicum Astoria Driscoll 115 kv Transmission Line: Serves PacifiCorp Substations Fern Hill and Knappa Svensen Youngs Bay Substation can be fed from either 115 kv line. No Local Generation
PAGE 4 North Oregon Coast System Overview Clatsop To Tillamook Sub
PAGE 5 Area Load Growth - Clatsop Base System Load Season (Non-Coincidental) System Load (PAC) Utilization Foreign Load Summer 2017 82.5 MW 59.9% 19.2 MW Winter 2017-2018 110.4 MW 66.6% 34.7 MW Growth Rate Season Clatsop Summer 0.4% Winter 0.1% Projected Load Growth Season (Non-Coincidental) System Load (PAC) Utilization Foreign Load Summer 2021 84 MW 61% 19.9 MW Winter 2021-2022 111 MW 67% 35.4 MW
PAGE 6 North Oregon Coast System Overview Lincoln City Study Covers: Transmission Switching Stations (Lincoln City District): Boyer 115 kv Distribution Substations (Lincoln City District): Devils Lake 20.8 kv Distribution Substations: Wecoma Beach Nelscott Gleneden
PAGE 7 North Oregon Coast System Overview- Lincoln City Transmission Source 230 kv source from Tillamook Substation (BPA); double circuit with 115 kv line from Forest Grove 115 kv source from Grande Ronde (PGE) via Boyer Boyer - Tillamook 115 kv Transmission Line Single breaker at Boyer (partial ringbus configuration) Serves PacifiCorp substation Devils Lake via two lines out of Boyer (Vanduzer #1 and #2) Serves Tillamook PUD substations Beaver, Hebo, and Nestucca Boyer Devils Lake 115 kv lines #1 and #2 : Devils Lake Substation can be fed from either 115 kv line, but is normally fed from #2 Auto-throwover scheme toggles substation to #1 line if #2 line is lost. No Local Generation
North Oregon Coast System Overview Clatsop PAGE 8
PAGE 9 Area Load Growth Lincoln City Base System Load Season (Non-Coincidental) System Load (PAC) Utilization Summer 2017 36.3 MW 72.6% Winter 2017-2018 45.5 MW 75.8% Growth Rate Season Clatsop Summer 0.6% Winter 0.3% Projected Load Growth Season (Non-Coincidental) System Load (PAC) Summer 2021 37.5 MW 75% Utilization Winter 2021-2022 46.1 MW 76.8%
PAGE 10 Planned System Improvements Overview Near-Term Planning Horizon (years 1 through 5): Additional breaker at Lewis and Clark Switching Station Fault Locating System Undervoltage load shedding at Young's Bay Replace Warrenton Transformer T-3782 Joint utility projects to address multiple contingency concerns Otis Substation
PAGE 11 Additional Breaker at Lewis and Clark Switching Station The 115 kv Sugarloaf line is operated as a three-terminal line between Astoria, Lewis and Clark, and BPA s Tillamook Substation. Any faults on the Sugarloaf line between Astoria and Tillamook or between Warrenton and Warrenton Tap will clear the entire line causing the loss of service to: Warrenton, Seaside, Cannon Beach, Necanicum, Nehalem, Mohler and Garibaldi Substations (18,344+ customers). A project has been proposed to expand the Lewis and Clark switching station and install an additional breaker. Installation will include routing the Lewis and Clark to Warrenton line into the station from the west and installing a motor operated switch to automatically sectionalize the line toward Warrenton Substation.
PAGE 12 Fault Locating System The Smart Tap device is new in the industry. It mounts onto an existing switch and sends both an indication that it saw a fault and the direction toward the fault to SCADA. These devices (or similar) could be attached to the switches on the south and west sides of the Cannon Beach Tap, on both line switches at Seaside, and on the south side of Warrenton Tap. Communication upgrades would be required. When a fault occurs, the SCADA displays would show both that the device saw a through fault, and which direction the fault current went. This would allow Dispatch to remotely open the appropriate switches by SCADA and restore service (followed by further mitigation for NERC compliance).
PAGE 13 Undervoltage Load Shedding at Young s Bay To adequately prepare for possible low voltages from outage conditions, it is recommended to add under-voltage load shedding at Young s Bay. There is already an under-frequency load shedding scheme at Young s Bay so only minor upgrades would be needed to achieve under-voltage load shedding, such as adding a high-side PT. The slow response time of under-voltage load shedding schemes should be taken into account, and well as the nature and importance of the customer load.
PAGE 14 Replace Warrenton Transformer T-3782 and T-3156 Due to a recent load addition, transformer T-3782 will be approaching 90% of its 12.5 MVA capacity by the summer of 2021 with the possibility of block load additions above the trend. T-3156 will approach 93%. Additionally, T-3782 is aging and has shown wear from the saline coastal environment. The transformers at Warrenton, Fern Hill, Knappa Svensen, and Young s Bay have wye-delta-wye windings, and there is currently no spare transformer in inventory that matches this phasing, thus it is recommended that both transformers at Warrenton be replaced with a single 25 MVA transformer having standard deltawye phasing. Adjacent distribution in Seaside matches this standard phasing, and could be tied to Warrenton. There are no feeder ties to adjacent distribution with wye-delta-wye phasing. One existing Warrenton transformer (most likely T-3156) could then be used as a spare to back up Fern Hill, Knappa Svensen and Young s Bay.
PAGE 15 Loss of Sugarloaf Line / Multiple Contingencies This study revealed that, at certain load levels in summer and winter, the Clatsop system does not have adequate reactive support to withstand an N-1-1 contingency involving the loss of either the Clatsop or Tillamook 230-115 kv transformers. Therefore the following solutions were explored and will be discussed further with BPA and the interconnected utitities: 1. Installing a 4-stage 80 MVAR capacitor bank at Seaside Substaiton would provide necessary reactive support in the Clatsop area during contingencies. 2. Installing a 230-115 kv transformer at Driscoll Substation (BPA) would strengthen the Astoria Driscoll 115 kv line for support during contingencies. 3. Radializing the system may prove beneficial for the short term, as an interim solution. 4. Separating BPA s Tillamook Forest Grove 115 kv line and Tillamook Carlton 230kV lines out of Tillamook Substation (common structures for 1.8 miles) would eliminate a credible N-2 contingency. All of these solutions are expected to increase the reliability of the Sugarloaf Line and the interconnected customers.
PAGE 16 Otis Substation Otis Substation has been planned for several years now. Its need is driven by a pending inability to supply local loads over the 20.8 kv distribution feeders 4A316 and 4A312 out of Devil s Lake. The land has already been acquired for it, though the project was postponed due to lack of growth. However, loads for 4A316 and 4A312 are now projected to be at 101% and 91% of their loading guideline limits (respectively) by 2021.
PAGE 17 Long-Range Planning Horizon (beyond 5 years): Complete the Ring Bus at Boyer Switch Station To resolve relaying deficiencies and improve reliability of service to Lincoln City, breakers should be installed at Boyer for each of the lines. Boyer station is already constructed to accommodate three additional breakers so implementation will require the new breakers, relays, switches, and necessary upgrades for a transfer-trip scheme with Grand Ronde. Backup for Young s Bay Substation To resolve mobile and spare transformer limitations, upgrading feeder ties and transferring some load to Fern Hill Substation is being proposed to alleviate loading on Young s Bay substation. To ensure the remaining load can be carried in the event of a Tsunami affecting Young s Bay substation, constructing a small distribution substation in the NW corner of Astoria Substation is being proposed.
PAGE 18 North Oregon Coast Area Study Questions?