Bureau of Reclamation PALISADES POWER PLANT TURBINE NAME PLATE RATING:H.P.. -39,500__; HEAD. 190.FT; SPEED 163.6R.P.M. 30,000 90 $363,740 Generator rating in kv-a.. Plate steel spiral Weight of turbine parts including hydraulic thrust to be carried by generator thrust bearing 269,000 lbs. Governor capacity in foot-lbs. 125,000 Gov. mfgr... Woodward Governor Co. Turbine WR2 12,600,000 500,000 EFFICIENCY DISCHARGE 25,000 30,000 20,000 HORSEPOWER AT DESIGN HEAD OF 190 FT. Regulating constant of unit (R.P.M.2x WR2÷H.P.). 8,876,500 at 190 ns of runner. 42.8 percent of design head; 2200_c.f.s. at 100 percent of design head; 2430_.c.f.s. H.P. at 183 ft. (Rated head-Mfr.) 39,500 H.P. at best efficiency equals 81.9. -percent of h.p. at full gate. Runaway speed at 245 ft. hd... 318r.p.m. equals...194. -percent of normal speed. Distance from center line of distributor to top of draft tube 2.67 ft. Depth of draft tube 27.33 ft. equals 277.percent of dig. D3. 10 20 30 40 50 60 1500 2000 2500 70 PREDICTED CHARACTERISTIC CURVES 80 90 100 % EFFICIENCY HYDRAULIC TURBINE DATA REV. 12-9-55 J.W.M. Figure 109.--Hydraulic turbine data for Palisades Powerplant. DISCHARGE IN C.F.S. Figure 110. --Unit 1 turbine--Water passage calibration. NOTES Units I thru 4 supplied from a common penstock REFERENCE USB.R DRAWINGS: DRAWINGS PALISADES DAM-GENERAL PLAN AND SECTIONS...456-0-117 TURBINE INLET PIPING WATER PASSAGE CALIBRATION UNITS 2, 3 AND 4. 456-0-140 456-0-1116,17,18 S MORGAN SMITH COMPANY (TURBINE) DRAWINGS: DISTRIBUTOR PLAN DISTRIBUTOR SECTION. SPIRAL CASE ELBOW DRAFT TUBE. GATE MECHANISM ASSEMBLY. 20 GATE LAYOUT_ WICKET GATE. 5840-00-1 5840-0E-1 1006-TO-1 5846-JI-I 5128-L-1 The head cover is made of welded steel plate construction and is in one piece. The discharge ring is formed by the lower portion of the stay ring, the stay ring being cast in five sections which were shop welded to the corresponding spiral case sections, the sections being bolted together to form a complete ring. Each stay ring section has stay vanes cast integrally with it. A packing box that can be repacked and adjusted without disturbing the guide bearing is provided where the main shaft passes through the head cover. The packing box has connections for water and grease lubrication and is provided with a lantern ring and four rings of packing. Packing boxes are also provided where the wicket gate stems pass through the head cover. The turbine is furnished with 20 wicket gates to control the supply of water to the runner. Each gate stem has three bronze-bushed guide bearings, one located in the bottom ring and the other two in the head cover, one below and the other above the packing box. Forced grease lubrication is supplied to each of the gate stem bearings independently. A double shear pin is provided in each connection between the gate-stem levers and the gate-operating ring. The shear pin is designed to withstand the maximum normal operating forces, but will break in either the opening or closing direction in case one or more of the gates becomes blocked. The mechanism is designed so that failure of one shear pin does not cause progressive failure of adjacent pins. Provision is made for adjusting any individual gate independently of the others. The turbine gate operating mechanism of each unit is powered by two oil-pressure, double-acting hydraulic servomotors having a total volume of 6,000 cubic inches, a design piston stroke of 13-1/2 inches, and a cylinder diameter of 18 inches. The servomotors have a combined capacity of 125, 000 foot-pounds and are designed to move the wicket gates through a full gate closing or opening stroke in 5 seconds under maximum head (including water hammer) of 346 feet with a minimum oil pressure of 250 pounds per square inch. At heads above rated head, the output of the turbine can be limited to rated output of the generator by an adjustable positive mechanical stop. The servomotors are equipped with adjustable slow closing devices for retarding the rate of closure so as to minimize the pressure rise in the penstocks. Locking devices are provided for holding the turbine gates in either the closed or open position against the maximum oil pressure. A 6-inch turbine air vent valve, automatically operated by a cam bolted to a wicket gate lever, is provided to break the vacuum in the draft tube and improve the operation of the turbine at part gate. A 2-inch ring header with four 1-1/2-inch pipe taps on each draft tube liner is provided for admitting compressed air to depress the water surface in the draft tube below the runner for synchronous condenser operation, or for motoring the units under minimum power requirements. Each liner has two threaded connections for two float cages which control the admission of compressed air. A compound pressure and vacuum gage is mounted in the turbine pit to indicate pressure conditions between the runner and the head cover. Another compound pressure and vacuum gage is mounted in the draft tube access passage to indicate pressure conditions below the runner. Each turbine spiral case, including the inlet, is made in seven sections. Five sections are shop welded to their corresponding sections of stay ring casting. Flanges are shop welded to the ends of each section and the sections bolted together to make the complete spiral case. The spiral case was designed so that with the turbine operating at rated capacity under a head of 190 feet, the velocity of the water at the centerline of the unit normal to the inlet section would not exceed 19 feet per second. The case was designed for an internal hydrostatic pressure of 150 pounds per square inch, and was tested in the field before being embedded in concrete, at a pressure of 225 pounds per square inch. A hydrostatic pressure of 82 pounds per square inch was maintained within the case while the surrounding concrete was placed. The method employed to support and secure the spiral case preparatory to and while embedding it in concrete made use of piers, jacks, and tie rods below the spiral case. Sufficient cooling water was circulated through the spiral case during placement of concrete to control the heat of hydration in the surrounding concrete. Prior to encasement of the case in concrete, all holddown bolts and tie rods were prestressed and securely welded and a final check made of the alinement. The welded plate steel draft tube liner extends downward to a point approximately 22 feet 10 inches below the centerline of the turbine spiral case. The liner is provided with ribs and anchors to the surrounding concrete to withstand the full hydrostatic pressure with tailwater at elevation 5386.0 and with an absolute pressure inside the draft tube equal to one-half atmosphere. A 24- by 30-inch man door is provided in the liner to give access to the underside of the runner for inspection and repair. The turbine pit liner is made of welded 1/2-inch plate steel. Openings are provided for servomotors and lubricating oil pumps. 90. Governors. The governors, furnished by Woodward Governor Co. for regulating the speed of the main generating units, are located on the generator floor elevation 5397.50 and are of the oil-pressure, distributing-valve, cabinet-actuator type with electrically driven speed-responsive elements. Each governor is a self-contained unit, the principal parts consisting of the actuator, restoring connections, two motordriven pumping units, pressure tank, sump tank, oil piping, independent alternatingcurrent generator, and other miscellaneous accessories required for regulating the speed of the unit by controlling the opening of the wicket gates. The pressure tanks are located adjacent to the actuators and the pumps are located inside of the actuator cabinets. The pressure tank and pumps of each unit are so connected as to permit repair or removal of one pump without interrupting the operation of the unit. The governor oil system was designed for an operating pressure of 300 pounds per square inch and operates at pressures between 250 and 300 pounds per square inch. The rated capacity of each governor at 250 pounds per square inch oil pressure is 125,000 foot-pounds as recommended by the turbine contractor. The governor is designed to supply an adequate quantity of oil to allow the servomotors to operate the turbine wicket gates through a complete opening or closing stroke, under a maximum effective head plus water hammer on the turbine of 346 feet, in 5 seconds with an oil pressure of not more than 250 pounds per square inch in the pressure tank, The speed-responsive element of each generator is driven by an alternatingcurrent motor receiving its power supply from a permanent magnet alternating-current generator. The independent generator is used exclusively for this purpose and is direct connected to the shaft of the main generator exciter. The enclosure for the independent generator contains two overspeed switches and two low-speed switches. The motors, generators, and speed devices were designed to withstand satisfactorily the maximum runaway speed of 318 revolution per minute of the turbine. Each governor is equipped with means for adjusting the rate of movement of the turbine gates between 5 and 15 seconds for a full gate opening stroke or a full gate closing stroke. The adjustment positively restricts the oil flow to the servomotor and is so arranged that the operation of the gate-limit mechanism control solenoid or any other device cannot cause the rate of movement of the turbine gates to exceed the maximum rate for which they are adjusted. The speed-responsive elements are capable of causing the governor distributing valves to pass oil in the direction to effect corrective movement of the turbine gates in consequence of speed variations of the turbines of twohundredths of one percent or less. With regard to governor timing, the final design report stated: "It is important that the minimum governor time used should not result in a maximum pressure including water hammer in the spiral case in excess of 150 pounds per square inch (design pressure of the spiral case). It is expected that this limitation will restrict the governor timing to a minimum of 8 seconds for closing the wicket gates from the fully opened position to beginning of cushioning, when the turbine is operated at 183-foot head or less. At heads above 183 feet it is expected that the governor timing will be restricted to a minimum of 8 seconds for closing the wicket gates from the part gate position, corresponding to rated output, to the beginning of cushioning. On the other hand, increasing the governor timing also increases the speed rise which is an important consideration for this plant, and should not exceed 85 percent of normal speed. (a) Control Plan.-- Palisades Powerplant is an attended plant, with each of the four units controlled from the floor elevation 5397. 50 through the unit instrument panel, governor actuator, or main control board. |