1 - Alaska Energy Data Inventory

surge tank (reject condition) is 1074 while maximum water hammer at theunit is 1,263 ft. Minimum WSEL in the surge tank (demand condition) andminimum water hammer at the unit are 765 and 597, respectively. Section 10in the main text discusses the sensitivity of the system to changes insurge tank location more fully.L. Speed Regulation and Hydraulic Capacity(1) Speed Regulation - Overspeed analysis is based on a standardpolar moment of Intertia (WR2) of 1,075,000 lb-ft 2 as established byHEDB. The synchronous speed of the turbine is 600 rpm and maximumovers peed is limited to 900 rpm or 50 percent over synchronous speed. Thewicket gate closing pattern is shown in figure 11 of Appendix 82. "WHAMO"was used to determine overspeed for the lowest net head at which 47,000 hp(blocked output) could be produced, i.e., 100 percent gate opening at anapproximate net head of 910 ft. The maximum unit speed resulting from thiscondition was 880 rpm (as shown in Plate 815) which represents a 46.7percent overs peed condition. Plate B2 shows the location of the run on thecharacteristics chart. Figure 17 of Appendix 82 shows the input file for"WHAMO" •(2) Hydraulic Capacity - Maximum discharge is 518 cfs and wasdetermi ned from the same "WHAMO" run that cal cu 1 ated overs peed • A manualcalculation assum"ing maximum losses, maximum tailwater and blocked outputresulted in a dishcarge of 511 cfs. The higher value calculated by "WHAMO"will be used for hydraulic capacity of the system.The pool elevationcorresponding to this discharge is 960.8 ft and is based on maximumtailwater, maximum hydraulic losses and a discharge of 518 cfs.(NOTE:The maximum flows are based on a prototype turbine throat diameter of 51.5inches, which was selected to produce 5 percent greater power at minimumand rated heads than the 35,000 and 47,000 HPspecifications).called for in the turbineBl-37