1 - Alaska Energy Data Inventory

in the power conduit. Condition E is used for checking the hydraulicstabi 1 ity of the surge tank and is based on a sma 11 load increase from37,500 to 39,000 hp, concurrent with minimum losses. All stabilityanalyses were made with a minimum reservoir elevation of 825 ft sincestability is most critical for this plan at minimum head conditions andwith minimum hydraulic losses. These turbine characteristics were used inthe IIMSURGP program, and are somewhat different from the final ized turbinecharacteristics shown on Plate B2.(2) Dworshak Turbine Model - After the initial surge tank studies(based on the Long Lake turb i ne model) were completed, HEDB recommendedus i ng the Dworshak turbi ne model study (for Dworshak Dam in Idaho). Aprototype turbi ne characteri st ics curve was developed for the Crater Laketurbine based on this recommendation and is shown on Plate B22. TheDworshak model was used in conjunction with the IIWHAMO II computer program.(3) Net Heads and Hydraulic Capacity - Calculation of net headsand hydraulic capacity is essentially the same as for the selected plandescribed in Hydraulics Appendix Bl.E. Surge Tank Diameter.(1) Thoma Formula Diameters - The Thoma Formula:F = AL......;.,..~-2gCHis a standard tool for selecting the first approximation of surge tankdiameters to meet stability requirements.In the formula the variables are defined as follows:F = Surge tank area (ft 2 ).A = Cross-sectional area of the power tunnel (ft 2 ).L = Length of the power tunnel from intake to surge tank (ft).B3-9