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Little Falls Powerhouse Modernization Presented by Brian Vandenburg Avista Utilities, Spokane, WA Slide 2 Slide 3 Welcome to Little Falls Act of Congress in 1905 Commissioned in 1912 Four units at 9MW each 600ft Spillway Slide 4 Why Little Falls? January 2010 Damaged breaker and commutator July 2006 Damaged breaker and commutator September 2010 Damaged breaker, commutator and generator winding Slide 5 Little Falls Scoping Vertical vs Horizontal Payback Logistics Foundation Unknowns Slide 6 Engineering Troubles Turnkey DesignIn House Design Slide 7 Little Falls Schedule Exciter and Breaker UpgradeCompleted Crane UpgradeCompleted New WarehouseCompleted Station Service Infrastructure UpgradeIn Construction Unit 3 OutageJuly 2014 - Feb 2015 Station Service Auxiliary SystemsSpring 2015 Unit 1 OutageJuly 2015 - Feb 2016 Headgate UpgradeJuly 2015 - Oct 2015 Unit 4 OutageJuly 2016 - Feb 2017 Spillgate System Upgrade??? Unit 2 OutageJuly 2017 - Feb 2018 Slide 8 Medium Voltage Breakers 4kV Breaker Upgrade Uprated the generator breakers and buswork Slide 9 Excitation System Exciter System Upgrade Amplidyne & Rotational Exciters replaced with Static Excitation System Slide 10 Crane Upgrade Replaced motors for all four motions. New cab and radio controls. Slide 11 Dealing with a small powerhouse Loading bay inside the plant is only 20ft wide, making logistics challenging Slide 12 Long Lake Warehouse The Long Lake Warehouse was built 8 miles from Little Falls to be shared between the two plants Slide 13 Station Service Upgrade New transformers, low voltage switchgear and motor control centers are being installed. Designed for future expansion. Slide 14 How to Get Funding Original Little Falls generator half and turbine being delivered to site Slide 15 Generator Replacement Generator frame design to LOOK like the old frame as much as possible Slide 16 Unit Upgrades: A Quick Look Replacing 9MVA generators with 12MVA generators Replacing turbines on units 1, 3 & 4. New PLC-based governor and HPU system on all four units Protection and Controls Upgrade New generator cables Rebabbit generator and turbine bearings Reinsulate field poles to class F Flow monitoring Aux System overhaul: Bearing Oil system, Brakes, Vacuum BKR, Wicket gate resleeving and painting Slide 17 Little Falls HED, circa 1915