APPURTENANT STRUCTURES, AND INSTALLATION OF GENERATING EQUIPMENT A. INSTALLATION OF TURBINES AND GENERATORS AND by 224. HYDRAULIC TURBINES GOVERNORS. (a) General Description.-The hydraulic turbines were furnished Baldwin-Lima-Hamilton Corp. of Eddystone, Pa., under invitation No. DS-5234. This was the largest single turbine contract in the Bureau of Reclamation history at the time (1960). The eight hydraulic turbines installed in Glen Canyon Powerplant are the vertical-shaft Francis type, with field-welded plate steel spiral cases and elbow-type draft tubes. Each turbine has a capacity of 155,500 horsepower, at full gate opening, when operating at 150 revolutions per minute under a net head of 450 feet. At a head of 510 feet and an output of approximately 150,000 horsepower, the required warranty efficiency was 90 percent. The governors for regulating the speed of the turbines are of the oil-pressure, cabinet, actuator type with electric-driven speed-responsive elements. They were furnished by Pelton Division of Baldwin-Lima-Hamilton Corp. under invitation No. DS-5562. Each governor is a complete unit, its principal parts consisting of the actuator with its relay valve, indicators, and controls, restoring mechanism, motor-driven pumping units, pressure tank, sump tank, and oil piping used for regulating the speed by controlling the gate opening of the turbine. The governors are rated at 441,700 foot-pounds at an oil pressure of 250 pounds per square inch, corresponding to the capacity of the turbine servomotors. factory level. Portions of the turbine parts were manufactured by S. A. Cockerill-Ougree of Seraing, Belgium. These parts consisted of the runner and runner caps; main shaft and sleeve; servomotors, rods, levers, links, pins, operating ring and wicket gates; head cover; distributor ring; stationary and rotating seal rings; guide bearing, bearing support and bearing cover; oil catcher; stuffing box, gland, and lantern rings, walkways, stairs, and handrailings. These are essentially all of the nonembedded parts. Early difficulties were experienced in casting some of the turbine parts but these were resolved by the subcontractor as the work progressed. In addition there were significant delays in delivery of the rotating parts of the turbines which caused field problems in meeting installation schedules. An item of note was that Baldwin-Lima-Hamilton's bid was based on a combination of foreign and domestic subcontracting of the elements of the turbines, which drew protests from foreign and domestic bidders and was submitted to the Comptroller General of the United States for a ruling before award of the contract. (b) Installation Procedure.-Installation of the draft tube liners and placement of second-stage concrete were the responsibility of the completion contractor. The draft tube liners were field welded in sections erected in place in the draft tubes. This method of individual welding of plates was selected by the subcontractor, Chicago Bridge and Iron Co., as the most economical method, both with respect to fabrication and field erection. Basically, the draft tube liners consist of two portions, conveniently referred to as upper and lower sections. The shorter upper section is flanged at the top for bolting to the discharge ring, while the lower end makes a field-riveted joint at the connection to the lower section of the draft tube liner. The lower draft tube liner was set on pipe jack supports as it was erected and welded, up to elevation 3124.51. The upper piece of this lower section, referred to as the makeup section, was not set at this time. Tierods and jack supports were installed and tightened to hold the liner rigidly in place. After final checking for alinement and grade, second-stage concrete was placed around the liner to about elevation 3124.0 by prepacked methods. The next step was installation and positioning of all tierod anchors and jack supports for the casing and stay ring. The makeup section, or upper piece of the lower draft tube liner, was then placed in approximate position followed by the lowering of the upper draft tube liner section into The turbine installation work was primarily the responsibility of the completion contractor, but the supply contract provided for certain field installation work by the turbine manufacturer in the assembly, alinement, and hydrostatic testing of embedded parts. This division of the work between the supply and completion contractors was sometimes difficult to handle in the field in that there were early problems in differentiation in responsibility for the work between crews. However, as the same subcontractor was employed by both the completion contractor and the turbine manufacturer, the problems were a matter of cost distribution rather than actual work conflict. The turbines and governors were built by experienced manufacturers of this type of equipment and there were no major technical problems at the *** ***erg was wwwww, repared for **the*/* was brought in by ***M, MH HH HS wanting parks and Dampoently beded to the disdwarge ring. The *th and match marks plared in the shop were most be petion the stay ring to lines established by How woning mens the stay ring halves were made up with barge slank bulle which were heated and stressed #petamined amount to make a tight joint lad o say they halone the spiral rses and extension gethone was pleat in the tumbine pit in approximate fitoi fare at bluding responsibility for the adequacy of this method up trough the drostatic testing of the spiral case. It was reported that this was the first time the Bureau had allowed this method of installation of spiral cases. From an installation point of view, the method proved to be very satisfactory, primarily due to the high quality of welding and supervision supplied by the subcontractor. When the spiral case had been assembled, the spiral case was alined and leveled by the use of turnbuckles, jacks and supports, as required by the turbine manufacturer. The head cover flange of the stay ring was leveled by the use of micrometer level attachments to a surveyor's instrument. This level and at DAM, POWERPLANT, AND GENERATING EQUIPMENT, ETC. alinement was maintained during hydrostatic testing and placement of concrete. The next step in the erection was the hydrostatic testing of the spiral case. The opening at the stay vanes was closed by the use of a temporary test ring supplied for this purpose. The tests of the spiral case proved that the fieldwork was completely watertight, and the stressing of the case through the working range of pressure proved the structural quality of the work. Upon satisfactory completion of the hydrostatic test, the pressure in the cases was brought to 225 pounds per square inch and maintained until the case was embedded and the concrete was cured. On completion of the hydrostatic test and checking of the tie-downs, jack supports, alinement, and levels, the spiral case was turned back to the completion contractor for the remainder of the erection and assembly of the turbines. bearing housing, and packing box were removed from the unit. The next operation was the placing of the portable boring rig for machining of the stationary seal rings. The basic four-wire plumbing, combined with rotation checking, was adapted to plumb the main shaft. The pit liner was placed on the spiral case with particular attention given to location of servomotor bases. This was difficult and time consuming during installation of the first three units, as the bases were refitted in the field to the range of desired tolerances; the problem was corrected at the fabrication shop on the last five units. The external piping and grout piping with vents were installed, a final check of all items to be embedded was made, and the unit was released for concrete placement. After the concrete had been placed and cured around the spiral cases, a final set of micrometer levels was taken on the stay ring flange. The adequacy of this method of anchoring and placing of concrete around the spiral case and pit liner was confirmed by these final level readings. The stationary seal seats were machined and the seats were bolted in position. The inside diameter of the wearing rings was machined to give proper clearance with the rotating seals of the runner. The head cover and boring rig were removed from the unit. The main shaft and runner were assembled on the generator deck using the coupling bolts stretched by 0.012 inch to give proper stress in the bolts. The throat ring was installed on top of the upper draft tube liner. The runner and main shaft were then placed in the unit on the ledge provided by the throat ring. The main shaft was plumbed and the runner was centered in the seal rings using shim stock in the runner clearance space. The wicket gates were placed in the bottom ring in their respective positions and the head cover installed over them. The remaining parts were then assembled in the turbine pit. The servomotors gate shifting ring, gate links, and guide bearing housing were assembled and adjusted. The turbine was then at a point it could be released for generator erection. Table 4 lists the chronology for the turbine erection. The bottom ring was placed, centered, leveled and bolted down, but not doweled at this point. The lower platform of the boring rig was placed in position on the top flange of the draft tube liner. This platform later proved to be too large to be removed after lower stationary seals had been placed and required extensive repair work in unit 1. The lower and upper stationary seal rings were placed in the unit at this time to be later hung from brackets on the head cover. The head cover with four wicket gates spaced 90° apart was placed in the unit on the stay ring flange. The head cover was carefully positioned to the unit centerline and was alined so that the four index wicket gates were plumb and with the proper clearances. The remaining wicket gate bores were checked with a tribar and were sanded or buffed for proper clearance. The head cover and bottom ring were then drilled and reamed for dowels. The guide bearing housing, guide bearing and packing box were alined to plumb wire centerline and drilled and reamed for dowels. The bottom platform of the boring rig was alined at this time and bolted securely. The head cover, wicket gates, guide bearing, guide Table 4.-Chronology for turbine erection Started Unit No. turbine installation The installation of the governors was under the direction of a factory erection engineer who performed all of the work inside of the cabinets including the operation of the governor during the first start. The completion contractor's work consisted of moving the equipment to the powerplant, alining and leveling it in position, and then placing a grout pad at the base of the cabinets. (c) Operational Tests.-The purpose of the operational tests was to determine that all phases of the installation work had been performed properly, all control devices had been checked and adjusted, and the equipment was ready for operation. As the generators and other equipment were involved in the turbine and governor operational tests, all testing was coordinated through the test coordinator. Preliminary tests were made before admitting water to the turbine. The plumb of the combined main shafts was checked from four plumblines at approximately 90° apart and the runner concentricity was rechecked. The governor and turbine wicket gates were operated several times, the gate squeeze was set, and the rate of movement and operation of all automatic and safety devices were checked and adjusted as required. The slow-closing devices on the turbine servomotors was adjusted to obtain proper rate of closure below the speed no-load positions. The timing of the wicket gates was set and their position recorded for use during other tests. The wicket gate timing could then be set without unwatering the spiral case. The runner clearances and shaft movement were measured under blocked servomotor conditions with full governor pressure applied. The next set of tests were the bearing runs. After the penstock and spiral case had been filled with water, the unit was started on manual control from the governor cabinet. The unit was started at reduced speed and brought up to synchronous speed in several steps. Each speed was held until all bearing and oil temperatures had leveled off. The next set of tests were the dry-out runs and rotor balancing, all of which were conducted by the generator contractor. The last section of testing was the unit load and load rejections. The unit was loaded in increments of one-tenth gate opening and held for one-half hour up to full gate opening, which was held for 15 hours. When the load reached one-fourth, one-half, three-fourths, and full load conditions the load was rejected and the unit allowed to return to speed no-load position. All the turbine and generator data was recorded for each individual unit. (d) Repair Work.-During the first months of operation of the turbines, it was noted that the stainless steel cladding on the runners was inadequate. Baldwin-Lima-Hamilton was notified of the deficiencies on February 25, 1965. On June 18, 1965, representatives of the Bureau, Baldwin-Lima-Hamilton, and one of the latter's subcontractors met at the Glen Canyon Powerplant. The purpose of the meeting was to inspect the runners and to develop a procedure to accomplish the repair work. It was determined the coating deficiency was the primary responsibility of the subcontractor supplier. One of the problems at this time was to determine the thickness of the stainless steel coating, in Start place, on the runners. The defects were apparent in units that had been in operation for some time; but in units that were not in service, or had only a small number of hours of operation, it was very difficult to determine coating thickness. An inspection determined that the repair work fell into two areas. Some areas were the responsiblity of Baldwin-Lima-Hamilton and others were the Bureau's responsibility. All parties agreed the work was required on all eight runners, but no workable basis was available to determine the amount of repair in the repair in the During early operations, the method of securing the throat ring to the upper draft tube liner was also found to be unsatisfactory. The bolts were sheared off during operation and the throat ring in unit 1 was discovered DS-5522. The contract provided for furnishing, installing, and testing eight 125,000-kv.-a., 90 percent power factor, 13,800-volt, 150-r.p.m., 60-cycle, vertical-shaft, hydraulic-turbine-drive, alternating-current generators, as well as the associated direct-current excitation system with controls, control of generator cooling water system by flow modulation, and specified spare parts for the generation units. Fabrication of the eight generators was started at the company plant on January 3, 1962, and installation at Figure 287.-Interior view of powerplant. The eight generating units have a total installed capacity of 900,000 kilowatts. P557-420-12678A, September 22, 1966. to be completely free during an inspection. The supplier was required to skip weld the throat ring to the upper draft tube flange-in addition to bolting-on all units and no further difficulties were experienced from this cause. the site on unit 1 began on December 26, 1963. Assembly and testing, except for final acceptance tests, were completed February 28, on 1966. Construction proceeded concurrently on the other generators. Unit 1 was placed on the line for the first time September 1, 1964; unit 2, September 18, 1964; unit 3, December 10, 1964; unit unit 4, February 9, 1965; unit 5, July 8, 1965; unit 6, October 6, 1965; unit 7, January 14, 1966; and unit 8, February 25, 1966. (b) Rotor Assembly.-The first generator shaft was lifted onto the rotor erection pedestal in the erection bay by one of the 300-ton overhead cranes on December 26, 1963. The rotor spider was next placed on the rotor shaft and bolted to the shaft flanges. A suitable scaffolding was erected around the spider for a working area and to carry the bundles of laminations for the rotor stacking. The overhead crane was also used to handle the 500-pound bundles of laminations. As the laminations were stacked, four presses were made to insure a tight mass. This was accomplished by placing pipe sleeves over the rotor rim bolts for the length of the unstacked portion. Rim stud nuts were then tightened on the pipe |