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<br />001695 <br /> <br />from the product of the generator rating, power factor, and percent <br />overload. This capacity is multiplied by the generator efficiency at <br />maximum horsepower to determine the maximum horsepower that can be pro- <br />duced by one generator. The gross head required for maximum horsepower <br />is computed as a function of the maximum horsepower. Next, the turbine <br />discharge at maximum horsepower is determined as a function of this <br />gross head. The iteration procedure begins here. <br /> <br />The fi rst step in the i terat i on procedure is to compute tail water e 1 eva- <br />tion from the powerplant discharge at maximum horsepower. Gross head is <br />then computed by taking the average of the beginning and end of month <br />reservoir elevations and subtracting the tailwater elevation. A new <br />value of turbine discharge is then computed as a function of the gross <br />head. If the gross head is greater than the maximum rated head spec- <br />ified in the CRSM control file, then the maximum rated head is used to <br />compute the new turbine discharge. <br /> <br />The new turbine discharge is compared to the initial turbine discharge. <br />If the discharges are within 5 ft3/s of each other, the iteration is <br />complete and the final computations are performed. If the difference in <br />discharges is greater than 5 ft3/s, then the iteration procedure is <br />repeated using the new discharge as the initial discharge. <br /> <br />When the iteration process is complete, the final gross head that was <br />computed is used to compute the horsepower produced by one generator. <br />This horsepower is then converted to power in kilowatts, also known as <br />generator capacity. The generator capacity is then multiplied by the <br />number of generating units to determine the powerplant capacity for the <br />month. The turbine discharge is also multiplied by the number of <br />generating units to determine the powerplant discharge, in cubic feet <br />per second. <br /> <br />The method of computing the number of hours of generation and sub- <br />sequently kilowatt hours of energy depends on the powerplant. The model <br />assumes that Upper Basin powerplants operate at one level of generation <br />and discharge. Hours of generation at Upper Basin powerplants are com- <br />puted by dividing the.total reservoir release through the powerplant for <br />the month in acre-feet by the powerplant discharge in cubic feet per <br />second, and applying the proper conversion factors to convert to hours. <br />The number of hours is then multiplied by the powerplant capacity (kilo- <br />watts produced) to obtain the energy produced for the month in kilowatt <br />hou rs . <br /> <br />The model assumes that Lower Basin powerplants are operated at two <br />levels of generation and discharge. This is an effort to simulate <br />actual operati ons at Lower Bas in powerpl ants because frequently a unit <br />is only partially loaded and, therefore, operating at less than maximum <br />efficiency. The lower level of discharge, called base flow, produces <br />60, 16, or 8 megawatts of power at Hoover, Davis, and Parker power- <br />plants, respectively. The upper level of discharge, called peak flow, <br />corresponds to the discharge computed earlier by the discharge iteration <br />procedure. The monthly release in acre-feet at base flow is computed by <br /> <br />45 <br />