volume 2 -sectionb tm rev 2 rfk update 11-19-04

8/3/2019 Volume 2 -Sectionb TM Rev 2 Rfk Update 11-19-04

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TM-1 TurbineTable of Contents

TM-1 Turbine .......................................................................................TM-1.1TM-1.1 Purpose and Function ..........................................TM-

1.1

TM-1.2 Drawings .............................................................TM-1.1

TM-1.3 Standards and Codes ................................................TM-1.1TM-1.4 Not Used..............................................................TM-1.2

TM-1.5 Rated Conditions .................................................TM-

1.2TM-1.6 Quantities and Descriptions ....................................TM-1.2

TM-1.7 Spare Parts ..........................................................TM-1.4

TM-1.8 Operation and Control of Equipment ..................TM-1.4TM-1.9 Shop Assembly....................................................TM-1.4

TM-1.10 Hydraulic Conditions ..............................................TM-1.4

TM-1.11 Operating Conditions ...............................................TM-1.5TM-1.12 Turbine Characteristics .............................................TM-1.5

TM-1.13 Data Required with Bid Price .....................................TM-1.5TM-1.14 Speed .......................................................................TM-

1.6TM-1.15 Efficiency Guarantee ..................................................TM-1.6

TM-1.16 Cavitation Guarantees .............................................TM-1.7

TM-1.17 Spiral Case ..............................................................TM-1.8TM-1.18 Stay Ring ................................................................TM-1.10

TM-1.19 Hydrostatic Pressure Test ......................................TM-1.12

TM-1.20 Head Cover .............................................................TM-1.12TM-1.21 Turbine Aeration ................................................TM-1.13

TM-1.22 Bottom Ring ...........................................................TM-1.14

TM-1.23 Discharge Ring ........................................................TM-1.15TM-1.24 Draft Tube Liner ......................................................TM-1.15TM-1.25 Draft Tube ................................................................TM-1.16

TM-1.26 Runner .....................................................................TM-1.16

TM-1.27 Shaft .........................................................................TM-1.19TM-1.28 Guide Bearing ...........................................................TM-1.21

TM-1.29 Lubricating Oil ........................................................TM-1.23

TM-1.30 Shaft Water Seal ......................................................TM-1.23TM-1.31 Guide Vanes and Operating Mechanism .................TM-1.24

TM-1.32 Servomotors .............................................................TM-1.25

TM-1.33 Turbine Pit Liner, Walkways, Platforms and Stairways .......................TM-1.27

TM-1.34 Drains .......................................................................TM-1.28TM-1.35 Not Used .................................................................TM-1.28

TM-1.36 Service Air Compressors ..........................................TM-1.28

TM-1.37 Electrical .................................................................TM-1.28TM-1.38 Not Used .................................................................TM-1.28

TM-1.39 Installation Equipment, Wrenches, Tools and Fixtures ........................TM-1.28

TM-1.40 Contractors Design Calculations and Data TM-1.29TM-1.41 Pressure Regulator TM-1.30

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TM-1.42 Inspection and Tests .............................................TM-1.32

Appendix A Unit 3 Turbine Index Test

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Kajakai Hydroelectric Project

Addition of Unit 2Technical Specification

TM-1 Turbine

TM-1.1 Purpose and Function

1 The turbine to be supplied under this specification shall be installed in an existingturbine bay to complete the three-unit powerhouse. It shall be constructed to suit the existing

water passages and powerhouse layout.

2 The dimension and weights of the assembled parts shall be within the capacity and

hook approaches of the existing 115-ton powerhouse crane.

3 The turbine shall be designed and constructed to provide a high degree of reliabilitywith minimum maintenance and shall be of rugged construction suitable for the operating

environment and resources of the Employer. The equipment shall incorporate features to

facilitate inspection and maintenance and to minimize maintenance requirements. Emphasisshall be placed on reliability, minimizing maintenance and protection of equipment rather

than on maximizing turbine efficiency. The design shall be tolerant of misalignment and

deformation of the concrete structures.

4 The Contractor shall integrate the design of the turbine, generator, governor, inletvalve and pressure regulator to meet all specified requirements without conflict between the

characteristics of the individual parts.

TM-1.2 Drawings

The accompanying drawings form part of this specification.

TM-1.3 Standards and Codes1 The equipment shall comply with the requirements of the latest revision of thefollowing standards where applicable.

CEA Hydroelectric Turbine-Generator Units Guide for Erection

Tolerances and Shaft Alignment

IEC 60041 International Code for the Field Acceptance Tests of HydraulicTurbines

IEC 193 Model Acceptance Tests of Hydraulic Turbines

IEC 60609 Cavitation Pitting Evaluation in Hydraulic Turbines, StoragePumps and Pump-Turbines

ISO 1940-1 Mechanical Vibration - Balance Quality Requirements of RigidRotors - Part 1: Determination of Permissible Residual

UnbalanceASME Boiler and Pressure Vessel Code, Section VIII, Division I

ASTM As specified herein

ANSI/IEEE 810 Hydraulic Turbine and Generator Integrally Forged ShaftCouplings and Shaft Runout Tolerances

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NEMA MG5.1 - 3.04 Standards for Vertical Hydraulic Turbine Generator Shaft

Runout Tolerances

2 Unless otherwise stipulated in this section of the specification, the equipment shallcomply with the requirements and the latest revisions of the applicable standards as listed in

Section TG-3.

3 If this specification conflicts in any way with any of the above standards or codes, the

more stringent requirement shall govern. However, the Contractor shall bring these conflictsto the Engineers attention to permit discussion at least

4 weeks prior to finalizing of Contractors design.

TM-1.4 Not Used

TM-1.5 Rated Conditions

1 The station is operated from an existing storage reservoir providing continuous power

using the available head and flow.2 The turbine shall be capable of continuous, stable operation at speed-noload and at

any output between that which corresponds to normal minimum turbine discharge, and

maximum unit output, and under any head within the range specified in TM-1.10. Suchoperation shall be without objectionable surges in power output or detrimental vibrations.

Acceptable fluctuations in power output shall be those which do not exceed plus or minus

2%. Acceptable levels of vibration are those which are in the good range per VDI Standard

2056.

3 The rated conditions shall be established by the Contractor based on the limiting

conditions described elsewhere in the specifications and the operating requirements specified

above. The nameplate rating shall be subject to acceptance by the Engineer.

4 The net head on the turbine shall be calculated in accordance with IEC 60041, Figure2. The total head at the turbine inlet shall be measured at the piezometer taps on the spiral

case inlet pipe.

TM-1.6 Quantities and Descriptions

1 The Contractor shall design, supply and install one turbine consisting of the

following.

Quantity Description

1 vertical shaft Francis type hydraulic turbine including spiral case, head cover,bottom, discharge and stay rings, guide bearing, shaft seal

1 lot guide vanes and operating mechanism2 servomotors for guide vanes

1 turbine aeration system including piping, valves, instrumentation

1 lot turbine pit platforms, walkways and stairs

1 lot runner blade templates

1 turbine design report

1 lot shop and field tests

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2 This work includes

turbine shaft to suit generator flange; detail design to be coordinated with thegenerator design

shaft seal water filtration system

guide bearing oil cooling system, if required by Contractors design

turbine pit liner draft tube liner all anchors, turnbuckles, fixtures, machine pads, jacks and foundation bolts for

field alignment and installation

all painting materials and test equipment for field painting and touch up painting

all special tools and devices for handling, assembly, installation, erection,

dismantling at site

all equipment, tools, instruments and devices for conducting field tests

all welding materials and equipment for site welding

any other item not specified above but necessary to complete the manufacture,assembly, machining, erection, commissioning and testing

all instruments, control and safety devices oil for the first filling of the turbine guide bearing oil system, including oil for

flushing

piping and electrical terminations and tie-ins to existing facilities

interconnecting wiring and piping between various parts of the equipment within

the turbine pit (for piping and wiring outside turbine pit see other sections of the

specification), including all couplings, valves, flanges, junction boxes, electricalenclosures required for continuation of piping and wiring outside turbine pit.

3 The Contractor shall assume responsibility for

field checking of the location and dimensions of all structures, equipment, piping

or other services that may affect its work field checking of all its connections to, or interfacing with, existing structures,

equipment, piping or other services quality of all materials and workmanship supplied by the Contractor entering into

the completed work

rigid adherence to the dimensions of parts as shown on drawings

strength of all parts of the turbine when subject to the most adverse load

conditions

ratings guaranteed in Contract

satisfactory performance of the entire work under all specified operatingconditions without signs of undue strain and without breakdown, cracking,

damage or deterioration of any of the parts due to faulty or unsuitable material,design, workmanship, handling, storage, transportation, assembly or erectionprocedure

freedom from excessive pitting of any part of the turbine under the specifiedoperating conditions in accordance with the Contractor's guarantee

freedom from abnormal vibration under the specified operating conditions.

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TM-1.7 Spare Parts

The Contractor shall supply specified spare parts, special tools and devices where detailed in

the Commercial Schedules and shall supply recommended spare parts for 2 years operation.Spare Parts for field testing and acceptance trials shall be provided by the Contractor. All

spare parts shall be identical electrically and mechanically to the corresponding parts in the

equipment, and shall be suitably packed and clearly marked ready for long-term storageindoors.

TM-1.8 Operation and Control of Equipment

The turbine shall be operated locally from the actuator cubicle on the turbine floor, from the

governor cubicle on the main floor and from the control room. The Contractor shall provide

all equipment, apparatus and devices to achieve the specified methods of operation andcontrol. The Contractor shall also provide all wiring and conduits between the turbine and

governor and other equipment.

TM-1.9 Shop Assembly

1 All equipment, fabrications and structures covered by the specifications shall be fullyassembled, as far as practical, in the Contractor's shop for inspection by the Engineer. Allnecessary adjustments shall be made in the shop to achieve the specified tolerances.

2 Prior to dismantling, each assembly shall be permanently and clearly matchmarked in

the shop to facilitate site erection. Dismantling shall be done only to the point required for

shipping. In particular, there shall be minimum disconnection of electrical wiring.

3 The Contractor shall complete the application of protective coatings in its shop asspecified in TG-14.

4 Shop assembly shall include, but not be limited to

assembly of all fabrications sectionalized for transportation assembly of stay ring to spiral case plate sections

tower assembly.

TM-1.10 Hydraulic Conditions

1 The general arrangement of the intake, power tunnel, water passages, draft tube and

tailrace is as shown on the drawings.

2 The operating conditions are as follows:

Centerline of unit distributor 962.0 m

Headwater level

- maximum (post spillway gate installation) el 1045.0 m- normal (present) el 1033.5 m- minimum el 1012.0 m

Tailwater Level- maximum (flood) el 972.0 m- minimum el 962.5 m

- normal el 962.8 m

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3 The turbine shall be designed to operate safely for extended periods of time at full

power under any head within the range of heads specified.

TM-1.11 Operating Conditions

1 The turbine will normally be required to operate, alone or in parallel with one or both

existing units, as a base load unit. During high reservoir levels, the unit could be running atmaximum output continuously.

TM-1.12 Turbine Characteristics

1 The Contractor shall submit to the Engineer a detailed report outlining how the

turbine characteristics have been determined. This shall include the details of any previousmodel tests used as a basis and any computer simulation performed to determine turbine

characteristics from similar units or models. The report shall list all input data used for

models or computer simulation, the output data obtained, a description of the methodologywith reference to any recognized standards which are applicable, and justification of the

characteristics derived in terms of existing units designed by the Contractor. The report shall

include: sample calculations for all calculated parameters, including efficiency, cavitation and

runaway speed

comparison of results with the guarantee requirements of the specifications.

model test curves for (where model used as basis)

unit power, unit discharge, efficiency versus speed for various guide vane openings

relation of power output, efficiency and discharge to the cavitation coefficient `sigma'for various guide vane openings and speeds corresponding to the head range to beencountered in service

relation of runaway to guide vane opening at not less than three net heads (design,

minimum and maximum) `Hill' diagram

curves for the turbine to be supplied showing

relation of efficiency, turbine output and discharge quantities with cavitation limitsindicated

relation of turbine discharge with guide vane opening for head range to beencountered in service

relation of runaway speed to guide vane opening for at least three net heads (design,minimum and maximum)

fluctuations in spiral case pressure, draft tube pressure, and shaft torque and draft tubenatural frequencies as a function of water flow with and without air admission

air admission pressures and flow rates

transient flow analysis and determination of pressure rise due to load rejection anddesign pressure for scroll case etc.

TM-1.13 Data Required with Bid Price

1 The Contractor shall submit with its Bid the following:

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detailed list of scope of work including specified and recommended spare parts, tools,tackle, installation and testing devices

general arrangement drawings of the proposed turbine features

brief description of all major components of the turbine including construction andmaterials as well as details of any deviations from the specifications

turbine performance curves, cavitation coefficient curves, Hill chart showing guidevane openings

turbine installation procedure and requirements

completed Technical Schedules

identify the prototype unit listed in TS-1, which most closely resembles the turbineoffered in the Bid, describing the head, speed, rated output, servomotor pressure, and

any deviations from the design that will be required for the machine offered in theBid

information on any subcontractors that the Contractor proposes to use for any majorcastings or weldments shall be stated.

2 The Contractor shall include any other drawings, catalogs, descriptions andphotographs necessary to present a clear picture of the type and class of equipment being

supplied.

TM-1.14 Speed

1 The preferred speed of the unit is 300 rpm. Rotation must be clockwise when viewed

from above. This speed and rotation matches the existing two units.

2 The Contractor shall guarantee that the runaway speed of the turbine at the maximum

specified head shall not exceed that stated in the Bid.

TM-1.15 Efficiency Guarantee

1 The turbine shall be designed for best efficiency at the design rated net head. Bidsshall include guaranteed efficiencies for the turbine operating at the design rated net head for80%, 90% and 100% rated output.

2 A single weighted average efficiency shall be guaranteed for the turbine and shall be

computed as follows:

% Rated Output

80 90 100

Weighting Factor 1 2 7

The weighted average efficiency shall be:

Efficiency x Weighting Factor10

The weighted average efficiency shall not be less than 91%.

3 The actual guaranteed weighted average efficiency shall be calculated using the head

as measured at the piezometer taps on the spiral case inlet pipe.

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4 Field tests shall be performed in accordance with IEC Publication No. 60041, Field

Acceptance Tests of Hydraulic Turbines.

TM-1.16 Cavitation Guarantees

1 Evaluation of cavitational pitting will be generally in accordance with the

International Electrotechnical Commission (IEC) Publication 60609 but shall also observethe following specific requirements.

2 The unit distributor centerline shall be set equal to the setting of the existing units 1

and 3.

3 Under the above conditions and with the specified tailwater levels, the material loss(due to cavitation only) shall neither impair the strength of the runner nor exceed the amounts

of cavitation pitting damage estimated from the lower line on the graphs in Appendix A of

IEC 60609. The material loss shall be determined for an 8000-h period of accumulatedoperation from the date that a Taking-Over Certificate is issued for the unit, or 24 months of

commercial operation, whichever comes first, or from the date of completion of cavitation

repairs or alterations as required by this Specification

4 The Contractor shall guarantee that material lost due to cavitation pitting damageduring the guarantee period shall not exceed 2 kg per runner and 1 kg for all other parts

combined (guide vanes, bottom ring, discharge ring, draft tube liner).

5 In addition, the Contractor shall guarantee that there shall be no single continuous

area of 200 cm2or more on the turbine where the metal thickness is reduced, due to cavitationpitting, by an average of more than 4 mm.

6 Contractors guarantee against cavitation pitting shall be based on the following

conditions of operation:

7 The operation of the unit at an output greater than the maximum normal output, as

given in the Technical Schedules, will not exceed 100 hours accumulated during theguarantee period.

8 The operation of the generating unit at a partial output less than the normal minimum

turbine discharge given in the Technical Schedules, and including operation at speed-no-

load, will not exceed 500 hours accumulated during the guarantee period.

9 The tailwater levels during turbine operation will not be less than that stated in TM-1.10. The maximum normal output at various net heads and tailwater levels shall be as stated

by the Contractor in the Technical Schedules.

10 In an effort to allow early determination and to limit the amount of cavitation pitting

damage, at the Employers discretion, an inspection of the turbine may be arranged afterbetween 1000 and 3000 hours of accumulated operation from the time the unit was placed in

service. Contractor shall provide the services of a competent engineer for these inspections.

The results of the inspection shall be reviewed with the Employer. The Contractor may, afterconsultation with the Employer, waive its presence at this inspection.

11 At the end of the guarantee period, the Contractor and the Employer shall also jointly

inspect and measure any cavitation damage, unless waived in writing by the Employer. If

excessive cavitation occurs, the Contractor shall immediately, unless otherwise approved by

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the Employer, reshape and resurface the cavitated areas by grinding, polishing, building up

by welding or other approved means, to remedy the cause insofar as possible, and propose

and implement corrective action to mitigate future pitting damage. Cavitation repairs shall beat the expense of the Contractor. If the damage does not impair the strength of the runner or

other parts, the Employer may require the cavitation pitting repairs to be delayed as long as

ten months.Wear due to erosion by suspended matter in the water or corrosion caused by chemicalcomposition of the water are not intended to be covered by the cavitation guarantee.

12 If the turbine fails to meet the above guarantee, the Contractor shall repair all pitted

areas in a satisfactory manner by welding. The final repaired surfaces shall have stainless

steel weld, having a minimum finished thickness of 3 mm. The Contractor shall also makethe necessary alterations to remove the cause or causes of this pitting or shall replace the

runner with one which is satisfactory. Contractor shall undertake all repairs at a time

convenient to the Employer and will undertake the repair work on a two 10-hours shifts perday, seven-days per week basis unless otherwise agreed by the Employer. For the purpose of

repair, the Employer will unwater the unit, remove the turbine covers and provide

compressed air and electric power free of charge to the Contractor; the Contractor shallprovide all necessary tools, materials and labor. The Employer will assume responsibility for

loss of capacity and generation during these outages, but the Contractor shall take all steps to

complete the repair work in a minimum time period. If the removal of the causes of this

pitting requires dismantling and shipping of the runner or any of the parts, the Contractorshall be responsible for all costs incurred. Subsequent to repair, the turbine will be subject to

the above cavitation guarantee for another period of 8000 operating hours. Notwithstanding

the provisions of the Defects Liability Period specified in the General Conditions, theguarantee will be renewed each time the turbine fails to meet the guarantee. If the turbine

runner fails to meet the cavitation pitting guarantee after repairs have been effected three

times, the Contractor shall replace the runner completely with a new runner of an improveddesign and shall bear all costs of runner replacement.

TM-1.17 Spiral Case

1 The case shall be of the spiral or volute type built from steel plate by welding, and

sectionalized as necessary for handling and shipment. Design and fabrication shall be in

accordance with ASME Boiler and Pressure Vessel Code, Section VIII, Division I. Thedesign shall be such that hydraulic losses are minimized. The casing shall be designed for the

maximum internal working pressure determined by the Contractor and accepted by the

Engineer (see TM- 1.41). Under this design pressure, the maximum stress, computed inaccordance with the Foppl formula, as follows, shall not exceed the stress recommended in

the ASME Boiler and Pressure Vessel Code, Section VIII, Division I:

f= pr x(R+ a)et 2 a

whereR = radius from vertical centerline of unit to vertical centerline of spiral case section under

consideration (mm)

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a = inside radius from vertical centerline of unit to point on spiral case section under

consideration (mm)

r = inside radius of spiral case section under consideration (mm)t = thickness of material at point under consideration (mm)

p = maximum internal design pressure (MPa)

e = joint efficiency as given in the ASME Boiler and Pressure Vessel Code,Section VIII, Division I, Unfired Pressure Vessels

f = stress in material at point under consideration (MPa).

The circumferential joints shall be designed to give a strength equivalent to that of the

longitudinal joints of corresponding sections. A corrosion allowance of 2 mm thickness shall

be added.

2 Field joints shall be made by welding. Spiral case inlet end shall match downstreamcoupling connecting extension piece downstream of inlet valve.

3 A watertight manhole shall be provided in the spiral case and an adequate saddle

provided to compensate for the metal removed from the casing for the manhole opening. Theclear manhole opening shall be 750 mm wide by 900 mm high. The manhole door shall haverounded corners and be hinged to open inward. The surfaces of the door and frame shall be

contoured and ground so that when closed the inside surface of the manhole door is flush

with the inside surface of the spiral case. The hinges shall be of rugged design and provided

with an adjustment to accurately align the door. A test cock or valve and nipple shall beinstalled in the spiral casing located immediately below the manhole.

4 Stainless steel bolts not less than 25 mm in dia and an endless gasket of 3-mm thick

Garlock red rubber, or equivalent, shall be provided to prevent leakage.

5 Stainless steel piezometer taps shall be provided on the casing for the purpose of

conducting performance tests. Each tap shall be designed to prevent stresses, caused byconcrete embedment or movement between the liner and the embedding concrete, from

fracturing the piezometer piping. Spiral case pressure gauge and index test piping is covered

under TM-4. Embedment in a resilient mastic is a preferred method. Embedment details shallbe acceptable to the Engineer. Any stress relief method that requires welding to the spiral

case will not be accepted. The following taps shall be provided.

Four piezometer taps equally spaced around the spiral case inlet pipe on diametersat 45 to the vertical, at a location determined by the Contractor subject to

acceptance by the Engineer, for measuring net head.

Four Winter-Kennedy piezometer taps (one or more of which may be provided onthe top ring of the stay ring) at locations to be determined by the Contractor

subject to acceptance by the Engineer.

6 All lugs, jacks, foundation bolts, anchors, tie rods and turnbuckles, bracing, etc,

necessary to facilitate assembly and prevent distortion during pressure testing and concreting

shall be supplied by the Contractor. The casing plates shall be formed so that field joint gapsand misalignments do not exceed 3 mm. The accuracy of the platework shall be proven in the

shop and all bracing, clips, dowels, etc, properly fitted before disassembly and shipment.

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Each casing shall be shop-assembled to its mating stay ring. All sections shall be properly

match-marked before disassembly.

7 Unless materials of spiral case dictate otherwise, all longitudinal joints in the spiral

case and stay ring shall be shop welded where possible. Shop-welded spiral case sectionsshall be stress relieved in a furnace at a temperature between 600C and 650C if required by

ASME code. The Contractor shall provide copies of the certified time-temperature record forfurnace stress relieving. Various sections shall be shop welded or cast to form pieces as largeas shipping clearances will permit. All welds on or adjoining the spiral case shall be subject

to 100% radiographic (RT) inspection, per TG-12. Where radiography is not suitable, other

weld inspection procedures shall be submitted to the Engineer for review during spiral casedesign.

8 After all field welding of the spiral case has been completed and before the spiral

casing is concreted in, the Contractor shall remove all extraneous lugs, brackets, etc, attached

to the spiral case and shall grind flush any irregularities or protuberances left on the surfaceof the spiral case.

9 Spiral case may be embedded in concrete while under internal hydrostatic pressure orprovided with additional temporary internal bracing, tie-rods, etc. If not embedded, the

Contractors design shall allow for expansion of the spiral case when in service by provisionof a compressible material at the interface with the concrete.

10 After the concrete encasement is cured, the Contractor shall remove all internal

bracing and grind flush any irregularities on the surface.

11 Special precautions shall be taken to prevent cracking in the spiral case plates

adjacent to the stay ring bolting flange faces due to the discontinuity in the stay ring acting asa "stress raiser".

12 One saddle flange outlet connection, complete with heavy removable stainless steel

grill or grating and studs and nuts, shall be provided for draining the casing. The size andlocation of this connection shall suit the existing embedded piping.

13 The spiral case shall be fitted with a gage pressure indicating transducer andtransmitter at the distributor centerline elevation. This shall give a 4-20 mA signal over a

range 0 to 100 m head.

14 Wetted surfaces of the spiral case shall be painted to system 1, TG 14, exposed

nonwetted surfaces to system 4, TG-14.

TM-1.18 Stay Ring

1 The stay ring shall be of welded plate steel or cast welded construction, heat treated

before final machining to relieve locked-up casting or fabrication stresses and sectionalizedas necessary for handling and shipment. It shall consist of upper and lower rings, rigidly heldtogether by stay vanes which guide the water to the guide vanes. For fabricated stay ring with

shrouded plate design, the vanes shall protrude through the upper and lower rings and shall

be welded with full penetration welds. For fabricated stay rings with parallel plate design, thestay vanes shall be welded to the flat plates with full penetration welds. The stay ring vanes

shall be designed and shaped to direct the water flow with a minimum head loss and to

eliminate vibrations.

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2 Machined flanges shall be provided for bolted connections between the stay ring and

the head cover, between the stay ring and the bottom ring or discharge ring. The pit liner

shall be welded directly to the stay ring.

3 The surfaces of the stay ring and the welded joints in contact with water shall beground to a smooth finish as specified.

4 Concrete placement under the stay ring shall be made using preinstalled concrete

tubing with small holes in the stay ring for venting, visual inspection of concrete filling and

final grouting. Air vent holes shall be provided through the webs in isolated pockets. Allholes shall be provided with closure plugs. The Contractor shall submit its concreting and

grouting procedure to the Engineer for review.

5 The design shall be such that the runner, head cover and guide vanes can be lifted

vertically for dismantling without having to dismantle anything below the head cover.

6 The stay ring shall be designed to support all loads superimposed upon it by the

concrete, hydraulic conditions during hydrostatic testing and operation of the turbine,

including the loads due to the generator and rotating turbine parts with the spiral case empty.

The stay ring shall also be designed to withstand the forces transmitted to it from the spiralcase under the maximum internal design pressure without the stresses exceeding the normal

permissible values specified herein.

7 The lower and upper rings of the stay ring shall be designed to transmit the loads to

the concrete with a bearing pressure not exceeding 4.0 MPa. The trailing edges of the stayvanes shall be shaped to minimize vortex formation.

8 The Contractor shall perform a complete stress analysis of the stay ring and identify

the most severely stressed areas according to the requirements of the ASME Code. Particular

attention shall be paid in calculating the maximum bending stresses at the vane to shroud (orparallel plate) and spiral case to shroud (or parallel plate) junctions. The calculated stresses

shall not exceed those permitted by the ASME Code. The calculations shall be madeassuming no support from the surrounding concrete. The method of computing stresses shallbe described in the Bid.

9 Plate steel for a fabricated stay ring shall be in accordance with ASTM A516, Grade

70, normalized. The Z- or through-thickness direction properties of the plate used for upper

and lower rings of a parallel plate design shall meet the requirements of ASTM A770 forresistance to lamellar tearing. In addition to the tensile and bend test requirements of the

material specification, representative samples of the plate steel shall be impact tested

according to the requirements specified in TG-7.

10 Parallel plates, if used in a welded stay ring, shall be examined by ultrasonic testing

(UT) at and in the vicinity of the welds to the stay vanes and the spiral case plates.

11 Welding and inspection of the stay ring shall be in accordance with requirements of

the specifications in TG. The welds shall be ground to a smooth finish. All other areas of the

stay ring in contact with water shall have a surface finish of 12.5 m . The stay rings shallbe stress relieved before machining.

12 All butt welds and welds to spiral case plate shall be examined by 100% radiographic

testing (RT) and stay vane to shroud welds shall be examined by UT. All welds shall also be

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checked by dye penetrant testing (PT) or magnetic particle testing (MT). Any defects

discovered shall be repaired in accordance with TG.

13 The wetted surfaces of the stay ring shall be painted according to TG-14 paint system

No. 1, exposed nonwetted surfaces to TG-14, system 4.

TM-1.19 Hydrostatic Pressure TestA hydrostatic pressure test of the spiral case and stay ring is not required unless the

Contractor elects to embed the spiral case under pressure, in which case the Contractor shall

submit details of the procedure for acceptance by the Engineer.

TM-1.20 Head Cover

1 The head cover shall be of fabricated steel plate. All butt welds shall be full

penetration and all welds shall be furnace stress-relieved. The head cover shall be of a heavy

construction, adequately ribbed and shaped so as to give rigid support to the guide bearing,

the operating ring and the bearings for the upper stems of the guide vanes. It shall be boltedand dowelled to a flange on the stay ring and along radial joints.

2 All major stress carrying welds shall be full penetration. Radial ribs of the head cover

may be fillet welded. The underside of the head cover shall be designed to minimize friction

and eddy losses between the head cover and the runner, and the space between shall beadequately drained to relieve water pressure and to minimize hydraulic thrust and leakage

(see TM-1.31).

3 Deflection of the head cover shall be small enough to prevent rubbing of the guide

vanes and binding of the guide vane stems. The method of computing deflections shall bedescribed in the Bid.

4 The head cover assembly shall have a machined seat for the turbine guide bearing,

guide vane regulating ring, shaft gland, guide vanes and any other equipment. The part of the

head cover which constitutes the guide bearing support structure shall be so designed as toprovide rigid support. A retaining ring or pads shall be furnished to prevent any lifting

tendency of the guide vane operating ring.

5 The guide seat for the guide vane operating ring shall be provided with a renewable

self-lubricated liner accurately machined so as to ensure minimum lost motion and friction inthe operation of the guide vane operating ring. Operating ring bearings shall be self-

lubricated.

6 At least four inspection holes shall be provided in the head cover to permit inspection

and check on clearances of the runner crown seals. The inspection holes shall have gasketedcovers bolted to the head cover.

7 Two self-lubricated bearings and a water seal with gland and V type packing shall be

provided for each of the upper guide vane stems. Suitable drains shall be provided for any

leaking water from the seals so that water cannot collect in the spaces between the ribs. Allbolts and nuts for the seals shall be of stainless steel. The lower surface of the head cover

shall be accurately machined to provide a Class A surface to the water passage at the

entrance to the runner as specified in TG-9. A wearing surface of stainless steel overlay orremovable stainless steel plates, attached with suitable stainless steel bolts and dowels, shall

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TM-1 Turbine

be provided on the lower face of the head cover above the guide vanes, extending radially

inward to the entrance of the runner. Raised lands shall be provided so that the leakage

through the closed guide vanes is a minimum, while providing adequate clearance for theguide vanes in the open position when the head cover is pressurized.

8 A renewable stainless steel seal ring, accurately machined to form a water seal with

the runner crown and shaped to reduce leakage, shall be secured with suitable stainless steelbolts and dowels to the head cover. Any hydrostatic pressure buildup behind the seal ringshall be relieved through built-in pressure relief holes. Leakage of water through the seal

shall be directed to the draft tube without building up pressure under the head cover. A price

reduction for substitution of a fixed seal ring may be offered.

9 A minimum of three piezometer connections shall be provided on the head coverpiped to a common manifold equipped with suitable valves and a pressure gauge. These

connections shall be arranged so that radial variations of water pressure under the head cover

can be measured. The pressure gauge shall be mounted on the turbine pit wall. All piping forthis system shall be stainless steel.

10 Walkways around the head cover and turbine bearing shall be provided with gratingsor suitable protected openings to facilitate visual inspections of equipment located below the

walkways.

11 An adequate number of eye bolts shall be supplied to lift the head cover. The headcover shall be designed to pass through the generator stator in one piece during erection and

dismantling and with the runner and shaft in place. Suitable opening(s) shall be provided in

the head cover for maintenance of the shaft seal without removal of the head cover.

12 Plate steel for a fabricated head cover shall be in accordance with ASTM A516,Grade 60 or 70.

13 For welding purposes, the head cover shall be considered as a pressure vessel.

14 All butt welds shall be examined by 100% ultrasonic (UT) or radiographic (RT)

methods. All other welds shall be fully examined by dye penetrant (PT) or magnetic particle

(MT) methods.

15 The head cover shall be painted according to TG-14. Paint system No. 1 shall be used

for wetted surfaces. Other exposed surfaces shall be painted with paint system No. 4.

TM-1.21 Turbine Aeration

1 An automatic turbo vent air valve of 150 mm minimum dia piping shall be provided

for admission of air through an opening in the head cover or through the generator shaft tothe runner cone, to permit smooth operation of the unit. The outlet end of the air vent pipe

shall terminate as close to the center of the runner cone as possible. The intake end of thepipe shall terminate at the upstream wall of the powerhouse. The valve shall act as a checkvalve or shall be provided with a separate check valve to prevent reverse flow. An additional

check valve shall be provided to ensure additional security against reverse flow. The opening

of the valve shall be adjustable to allow control of the air flow to the draft tube. Apadlockable isolating valve shall be provided so that repairs can be made on the air valve

without shutdown of the unit.

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TM-1 Turbine

2 If aeration of the turbine is provided through the center of the shaft, an air head shall

be provided by the Contractor on top of the generator. The air head shall be connected by the

Contractor-supplied piping to the air vent valve. The Contractor shall coordinate the designof the air head and piping with the generator supplier.

3 The air vent valve shall have means of automatic adjustment for opening and closing

at various guide vane positions and for altering the rate of closing. The air valve and pipingshall be large enough to permit rapid air entry at atmospheric pressure and without noiselevels exceeding 85 dBA.

4 In a straight section of the turbo vent piping, the Contractor shall install a pitot tube

head located at the center of the pipe and adequately supported. The pitot tube will be located

at least six diameters downstream and at least 2 dia upstream from any flow disturbance suchas an elbow or a valve. The pitot tube shall be connected to a calibrated gauge mounted on

the turbine pit wall. The velocity head measured by the pitot tube shall be converted into air

flow in the pipe. The gauge readings shall read flow in cubic meters per second.Alternatively, the Contractor may install a commercially available air flow measurement

device such as `Annubar' in the turbo vent piping.

5 The design of the turbo vent outlet and runner cone shall ensure that the unit will

draw sufficient air, at atmospheric pressure, under critical operating conditions to ensurehydraulic stability.

TM-1.22 Bottom Ring

1 The bottom ring shall be made from cast steel or welding plate steel, sectionalized as

necessary for handling, shipment and removal. If the ring is of welded design, all butt welds

shall be full penetration and all welds shall be stress relieved before machining.

2 The bottom ring shall be of heavy, rugged construction, and all necessary anchors and

adjusting screws shall be provided. Bronze self-lubricating bushings shall be provided for the

lower stems of the guide vanes. The bushings shall be an interference fit in the bottom ringand shall be locked in place.

3 A wearing surface of stainless steel overlay or removable stainless steel plates,

attached with suitable stainless steel bolts and dowels, shall be provided on the upper face of

the bottom ring below the guide vanes, extending radially inward to the entrance of the

runner. Raised lands shall be provided so that leakage through the closed guide vanes is aminimum, while providing adequate clearance for the guide vanes in the open position when

the unit is pressurized.

4 A renewable stainless steel seal ring, accurately machined to form a water seal with

the runner, shall be secured with suitable stainless steel bolts and dowels to the bottom ring.

The seal ring shall be designed to minimize leakage. Any hydrostatic pressure buildup behindthe seal ring shall be relieved by built-in pressure relief holes. A price reduction for

substitution of a fixed seal ring may be offered.

5 Wetted surfaces of the bottom ring shall be painted to system 1, TG 14.

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TM-1 Turbine

TM-1.23 Discharge Ring

1 The discharge ring shall be of cast steel or plate steel, sectionalized as necessary to

facilitate shipment and handling. If the discharge ring is of welded plate steel, all butt weldsshall be full penetration, and all welds shall be stress relieved before machining. It shall be of

heavy section and adequately ribbed externally to secure proper anchorage to the concrete

and to prevent distortion. Where Contractors design indicates that cavitation may occur atthe discharge ring, stainless steel overlay or removable facings shall be provided.

2 The discharge ring shall have a flange at the top for bolting to the bottom ring or stay

ring. The lower end shall have either a flange for bolted connection or an extension for

welded connection to the draft tube liner. The necessary foundation bolts shall be supplied

for anchoring the discharge ring to the concrete, and adjusting jacks with steel bearing platesshall be furnished to facilitate leveling during installation. Suitable grout holes with plugs

shall be provided in the discharge ring, as required, for concreting and grouting.

3 The lower end of the discharge ring or, alternatively, the draft tube liner flange shall

be machined to form a ledge for support of the runner and turbine shaft when disconnected

from the generator.

4 Wetted carbon steel surfaces of the discharge ring shall be painted to system 1,

TG-14.

TM-1.24 Draft Tube Liner

1 The draft tube liner shall be of plate steel having a minimum thickness of 12 mm andshall be adequately ribbed and stiffened to prevent distortion. The top of the liner shall be

machined true to level and diameter for bolting or field welding to the discharge ring. It shall

extend to a point 1 m beyond the tip of the central pier nose, and include a steel nosecovering 1 m long anchored to the pier. If the Contractors design require a longer liner

extent, the Contractor shall provide separate pricing for the additional length required. The

Contractor is responsible for ensuring a smooth transition from the termination of the liner to

the existing concrete draft tube, including grouting, concreting, formwork, preparatorytreatment of existing concrete, embedded steel, anchors, etc. The first 0.5 m of the liner

below the runner band shall be faced with or constructed from stainless steel conforming to

ASTM A743 Grade CA 6NM.

2 A watertight and airtight manhole door, having a clear opening not less than 750 mmwide by 900 mm high, complete with studs and nuts, shall be provided in the draft tube liner

in a location determined in consultation with the Engineer. The manhole door shall have

rounded corners, hinged to open outward into the access passageway. The hinges shall be ofrugged design and provided with an adjustment to align the door. Stainless steel bolts not less

than 24 mm in dia, and an endless gasket of 3 mm Garlock red rubber or approved equivalentshall be provided to prevent leakage during pressure surges. Stainless steel jacking bolts shallbe provided. The inside surface of the door shall be contoured and ground flush with the

inside of the draft tube liner. A test cock which provides a clear bore in the open position for

rodding shall be installed in the draft tube liner below the door. A draft tube pressure andvacuum gauge connection shall also be furnished in the liner. A 300 mm dia flanged pipe

connection shall be provided below the door for draining the draft tube.

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TM-1 Turbine

3 The liner shall be completely assembled and matchmarked in the shop with all ribs

accurately fitted. To facilitate field installation, the liner shall be shipped in as few pieces as

shipping limitations will allow.

4 A sufficient number of leveling screws, jacks, turnbuckles and hold-down bolts shallbe provided to permit centering, leveling and securely holding the liner, both vertically and

laterally, during assembly and while concrete is being placed. Suitably spaced grout holesshall be provided to facilitate final lowpressure grouting of the liner after shrinkage of theembedding pour has taken place. Suitable plugs shall be installed in the grout holes and

ground flush after grouting is completed.

5 Wetted surfaces of the liner shall be painted to system 1, TG-14, nonwetted exposed

surfaces to system 4, TG-14.

TM-1.25 Draft Tube

The draft tube is of the elbow type. The Contractor shall be responsible for reviewing the

existing draft tube substructure concrete outline with regard to design and details which

could affect the performance of the new unit. Removal of the existing bulkhead is specifiedelsewhere in these specifications.

TM-1.26 Runner

Design and Construction

1 The runner shall be a fabricated one piece runner made from plate with stainless steel

blades and band. Plate steel blades shall be appropriately contoured by machining, to ensurehigh turbine efficiency. The runner crown may be stainless steel or carbon steel, with a

stainless steel surface at the head cover seal.

2 A fabricated stainless steel runner cone shall be bolted to the underside of the crown.

All bolting shall be stainless steel.

3 Materials for runner construction shall be as follows:

Runner blades, band ASTM A487/A743 CA 6NM

Runner crown CA 6NM (as above) or ASTM A516M, Gr 485

4 Mill Certificates shall be provided to the Engineer for the turbine runner blades,

crown and band, coupling bolts, runner cone and wearing rings.

5 The runner shall be connected to the shaft by through-bolts with nuts and locking

devices. The coupling bolt holes in the runner shall be line reamed with the runner and shaftassembled. The fit of the bolts shall be in accordance with the minimum values shown in the

most recent issue of ANSI/IEEE 810. The connection shall be designed for tightening and

holding from above, as required for incremental assembly.

6 The contour of the runner blades shall be accurate and shall be finished so that thevane profile precisely conforms to the design within the tolerances set out in IEC Publication

60193, except as otherwise specified herein. The blades shall be evenly and symmetrically

spaced. Before shipment, Contractor shall submit proof that the finished runner contours andshape agree with the design requirements.

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TM-1 Turbine

7 If a fabricated runner is used, all welds shall be full penetration and furnace stress

relieved. The Contractor shall provide copies of the certified timetemperature record for

furnace stress relieving. During stress relief, the weldment shall be adequately supported inthe furnace to prevent distortion due to its own weight. After stress relief, the welds shall be

chipped or ground to the correct contour, and shall be magnetic particle inspected.

8 The joint preparation between the blades and the crown and band shall be doublegrooved to ensure complete penetration through the full thickness and length of the joint. Atthe joints near the entrance and discharge edge of the blades the weld root area shall be

gouged to sound metal by suitable means after sufficient weld metal has been deposited from

the first side. The gouged area shall be magnetic particle inspected prior to depositing anyweld metal on the second side of the joint. The length of weld root to be gouged at each

entrance and discharge edge shall not be less than 15% of the blade length.

9 All welding shall be visually inspected frequently for cracks and other defects. After

the final weld is completed and the surface ground smooth to the final surface, the weldedjoint shall be fully inspected by magnetic particle method. In addition, the welds at each

entrance and discharge edge of the blades shall be inspected by ultrasonic methods over a

distance of at least 15% of the blade length. Any defects shall be chipped or gouged toexpose sound metal prior to any subsequent welding. The reweld area shall be inspected

during welding and after completion as required for the original weld.

10 The welding filler metal or electrodes used shall be of a grade suitable for the

material being welded, and shall be suitable for all position welding. No welding electrodelarger than 3/8 in. diameter shall be used. When welding the blades, a jig fixture shall be used

to ensure proper position and spacing of the runner blades.

11 The blade positions shall be checked several times during welding to assure that the

proper position is maintained. Care shall be exercised during the welding operations, tominimize distortion by employing adequate bracing, intermittent skip welding around the

runner, and avoiding excessive localized heating.

12 During welding operations, the runner shall be positioned so that insofar as practical

all welds are made in approximately the down-hand position.

13 Peening may be used to control distortion and for relieving localized stresses;however, the first and last layer of deposited weld metal shall not be peened.

14 Prior to assembling the runner for welding, all accessible water passage surfaces shall

be finish machined and/or ground to the correct contour, except in those areas that, due to the

manufacturing procedure, must be finished following the completion of all welding. Anyirregularities which might be conducive to pitting shall be corrected by welding and grinding.

15 After machining and finishing, the run outs on the band and crown sealing surfaces,the coupling face and location recess shall be measured and recorded. These records shall be

made available to the Engineer on request.

16 The runner seal rings shall be renewable and of a weldable grade of stainless steel.Special attention shall be given to the reliability and anti-galling characteristics of the

rotating and stationary rings which shall be given securely fastened in place using stainless

steel bolts and dowels.

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TM-1 Turbine

17 Contractor shall prepare and submit to the Engineer for acceptance a detailed

fabrication procedure for the runner before starting fabrication. The fabrication procedure

shall include details of welding, peening, preheating, nondestructive testing requirements andstress relieving.

18 The runner shall be designed to withstand safely the stresses due to operating at

runaway speed under conditions of maximum head with no load on the generator.

19 The runner shall be designed to support its own weight and the weight of the turbine

shaft when disconnected from the generator shaft with the runner resting on a shoulder of thedischarge ring or draft tube liner flange.

20 The radial clearances between the runner and stationary seal rings shall be as small as

possible, consistent with safe operation and with the clearances required in the turbine and

generator guide bearings. Provision shall be made for vertical movement of the runner andshafts to allow for adjusting and dismantling the generator thrust bearing and for clearing the

generator shaft coupling spigot.

21 Provision shall be made to permit aeration of the draft tube through the runner crown

should operating experience show this to be necessary or desirable.

22 For Contractors information, the existing Units 1 and 3 runners were manufactured

by Allis Chalmers with a discharge diameter of 79 in. and 15 blades and for a rated head of

215 ft.

Runner Profile and Surface Finish

1 The quality control for the runner, as outlined below, is based on the guidelines given

in the Electric Power Research Institute Report EPRI AP 4719 dated August 1986. The

surface profile classes are defined in TG 9.

2 The Contractor shall fabricate and maintain accurate templates of durable material to

check blade profile during runner manufacture and on completion, prior to shipment. Thetemplates shall be mounted in such a way that their shapes are not disturbed during use. A

complete set of templates shall be provided to the Employer at the time of shipment of the

runner.

3 The Contractor, before manufacturing begins, shall prepare a written inspection plan

of steps to be taken to ensure homology from the design to the final manufactured runner.

The plan shall be submitted to the Engineer for review. The plan shall specify the acceptance

criteria (i.e., tolerances) and shall include sketches showing locations of measurements withsample record sheets for tabulating the results of any inspection. The results of the homology

checks shall be documented in reports submitted to the Engineer as runner manufacturing

progresses.

4 The surface profile classes (TG-9) shall, as a minimum, be applied in the followingmanner.

Area Class

Suction Side of Blade

- leading edge extending 0.06 D* toward trailing edge A

- trailing edge extending 0.1 D toward leading edge A

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TM-1 Turbine

- from band one third blade length toward crown A

- remainder of suction surface B

Pressure Side of Blade

- leading edge extending 0.06 D toward trailing edge A

- from band one third of blade length toward crown A- remainder of pressure surface B

Crown and Band

- fillet areas Same as adjacent

blade surface

- Remainder B*D = runner discharge diameter.

5 The maximum deviation in blade profile shall meet IEC 60193.

6 The Contractor shall establish more restrictive controls than those specified above if

he considers this necessary to suit design and operating conditions and ensure all guaranteesare met.

7 The Contractor's engineer responsible for the runner hydraulic design shall inspect the

runner at various stages of manufacture, and shall certify in writing that the manufacturing

process is such that the specified tolerance for hydraulic design will be achieved. Copies ofthe written certification shall be submitted to the Engineer. This certification shall be

provided at the following stages.

Blade pattern;

After blade forming;

After machining of first blade is complete;

After fit up of four to six blades; After final machining.

Balancing of Runner

1 The runner shall be accurately balanced statically and dynamically in the shop to

meet balance quality G6.3 of the ISO Standard 1940 at normal operating speed.

2 The hydraulic unbalance of the runner shall be within 1.5% of the average vent

opening. The hydraulic unbalance shall be calculated by vectorially adding the averagedischarge vent openings for each of the blades. The final vent measurements shall be made in

the shop after all welding and grinding work on the runner is completed.

TM-1.27 Shaft1 The turbine shaft shall be made of forged carbon steel, properly heat treated inaccordance with TG-7. It shall be provided with integrally forged coupling flanges top and

bottom for connecting to the generator shaft and to the runner hub, respectively. It shall be of

ample size to operate at any speed up to the full runaway speed without detrimental vibration

or distortion and to operate at maximum output without exceeding normal design stress.

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TM-1 Turbine

2 The Contractor may propose a hollow fabricated shaft design if it can be proven that

such a design does in fact meet the requirements of the specification. All drawings and

welding procedures for this alternative design shall be submitted to the Engineer for reviewbefore manufacture commences.

3 The turbine shaft shall be accurately machined all over and polished where exposed

to view from the guide bearing journal, up to and including the coupling and the couplingguard to a surface finish of 3.2 m. All welded parts of the shaft shall be coated in accordancewith System 1 of TG-14 to prevent corrosion and corrosion cracking. The guide bearing

journal and the shaft seal sleeve shall be polished to give a finish not to exceed 0.4 m Ra (Ra

= roughness average as defined in ANSI/ASME B46.1).

4 The shaft shall be hollow bored to a diameter of at least 150 mm throughout its entirelength and shall have a finish of approximately 3.2 m. The Contractor shall perform a

borescope inspection of the shaft material.

5 The shaft shall be provided with a boss to form the journal at the bearing and a boss

to support a wear-resistant sleeve at the shaft seal. The sleeve shall be made in two halves,

removable and renewable and securely fastened to the shaft. After assembly on the shaft, thesleeve shall be accurately machined and polished. The sleeve shall be made of AISI 410

stainless steel or approved equivalent. Effective means shall be adopted for the prevention ofcorrosion of the shaft underneath the sleeve. Suitable oil baffles and water deflectors shall be

provided between the main guide bearing and the shaft seal.

6 The amount of shaft runout shall be checked by rotating the finished turbine shaft in a

lathe or aligning device in the Contractor's shop. The amount of runout shall not exceed thetolerances recommended for turbine shafts in NEMA Standards for Vertical Hydraulic

Turbine Generator Shaft Runout Tolerances MG 5.1. Two bands shall be marked on the shaft

for use with reference plugs for alignment. The bands shall be concentric with the shaft andpolished to a finish of 0.4 m Ra. The turbine generator shaft coupling shall be designed in

accordance with ANSI/IEEE 810. The lower shaft coupling to the runner shall bedimensioned so far as is practicable in accordance with ANSI/IEEE 810 standards.

7 Immediately above the bearing housing, a circumferential line shall be inscribed onthe shaft, and an adjustable pointer shall be mounted on the bearing housing opposite this line

to indicate if any axial movement of the shaft occurs, and to permit realignment after thrust

bearing dismantling.

8 The outer cylindrical surface of the flanges shall be marked with `H' to show the highspot on the face of coupling.

9 The Contractor shall finish the recess of the female half coupling of the generator

shaft to standard tolerance.

10 The Contractor shall be responsible for the final reaming of the coupling bolt holes

and coupling up and aligning of the turbine and generator shaft in the field, including use ofsteel drilling template and pin gauge for the coupling. The Contractor shall furnish the

coupling bolts for coupling the shafts together, as well as the nut guard on the turbine side of

the coupling.

11 The field alignment procedure for shaft and bearings shall be accepted by theEngineer prior to the start of assembly. The publication "Hydroelectric Turbine-Generator

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TM-1 Turbine

Units Guide for Erection Tolerances and Shaft Alignment", published by the Canadian

Electrical Association, 1990, is recommended as a basis for the assembly procedure. Under

the conditions of rotational test, the runouts at the turbine bearing shall not exceed 0.02mm/m length of shaft between the generator thrust bearing and the turbine guide bearing.

12 In operation of the assembled turbine and generator

static runouts at the turbine guide bearing shall not exceed half the amount of thetotal bearing clearance across the diameter

vibration shall not be excessive relative to best modern practice for similar units.

TM-1.28 Guide Bearing

1 The turbine guide bearing shall be of the babbitted oil-lubricated type preferably self-

cooled and shall be self-lubricating oil flow design. The bearing shall be self-pumping for oilcirculation and shall be designed and constructed to be free from oil throwing or from

emission of oil vapor.

2 A segmented pad type bearing is preferred with individual adjustment of the positionof the pads and of the alignment. It shall be as near to the runner as possible, consistent withconvenient access to the shaft water seal. The bearing arrangement shall permit axial

movement of the shaft.

3 The bearing reservoir shall have removable top cover plates to prevent dirt or foreign

matter from entering the bearing. The bearing shall be made of cast steel or welded platesteel of heavy construction. The bearing shall be rigidly supported on the turbine head cover.

Irrespective of the material used, the bearing shall be stress relieved between the rough and

finished machining operations.

4 The bearing shall be split vertically into two or more sections to facilitate dismantling

and the mating sections shall be dowelled securely. The design of the bearing and oilreservoir shall permit their inspection, adjustment or removal without disturbing the head

cover or major dismantling of other parts of the turbine. The bearing design shall be such thatno water shall enter the lubricating system via the shaft seal and there shall be no loss of oil

by leakage past the lower oil shedder or by overflow from any part of the oil system under

any condition of normal operation within the range of headwater and tailwater elevations

from speed-no-load to full load.

5 The unmachined internal portions of the bearing and the inside of the oil reservoir

shall be sandblasted, blown clean and painted with an oil resistant enamel applied as

described in TG-14, Paint System 2.

6 Babbitt shall be in accordance with the specification outlined in TG 7. The babbittlining shall be securely anchored or bonded to the shell and shall be accurately bored and

shall be suitably grooved for oil circulation. The lining shall be fitted and scraped where

required to eliminate high spots.

7 The bearing shall be of adequate design to operate under all starting, running andstopping conditions met in normal operation, fault conditions, commissioning and

maintenance.

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TM-1 Turbine

8 Suitable lifting eyes and backing out studs shall be provided for use in removing and

installing the bearing.

9 If cooling of the lubricating oil is necessary, a water cooled heat exchanger, 120%

capacity, shall be provided, designed for immersion in the oil reservoir. The cooler shall bethe straight through design made of stainless steel. All connections shall be made outside of

the oil reservoir. These shall be arranged such that water from a leaking connection cannotdrip into either the bearing or the oil reservoir. A water-in-oil sensor shall be provided withalarm light on the turbine and generator gauge panel.

10 Cooling water will be available at a temperature and quality to be determined by

Contractor at the site. See also TM-4.12. If further filtration is required, the Contractor shall

provide all necessary equipment, controls and instrumentation.

11 The bearing shall be capable of operating without damage

continuously at any speed up to full rated speed

for 30 minutes at runaway speed

for 15 minutes at rated speed without cooling water or oil circulation for 5 minutes at runaway speed without cooling water or oil circulation

12 The Contractor shall be responsible for making the connection to and supplying all

piping inside the turbine pit, including the necessary tees for the main shaft seal and bearing

supplies. All piping shall be provided with a sufficient number of Victaulic couplings topermit ease of removal.

13 The lubricating oil system shall have sufficient capacity to supply the required

amount of oil to the turbine guide bearing, and the oil reservoir shall have sufficient capacity

to hold all the oil in the entire bearing system, and to provide cool oil to the bearing under allconditions of load. The bearing design shall prevent the leakage of oil down along the shaft

and shall provide for returning oil from the bearing to the reservoir. Piping for filling the

bearing and reservoir shall be separate from the drain piping.

14 The Contractor shall also supply and install the following indicating and protectiondevices for the guide bearing:

two dial type temperature controllers to indicate the hottest part of the bearing.Each controller shall have two sets of separately adjustable contacts suitable for

operating alarm and tripping circuits at 220 V dc. The temperature controllersshall be mounted by the Contractor on the governor actuator cubicle (see TM-2)

two resistance temperature detectors (platinum, 100-ohm, three-wire, doubleelement) one for the bearing and one for the oil so that both the bearing and oiltemperatures may be indicated and recorded at a remote location

one turbine bearing water flow transducer 4 to 20 mA with direct readinginstrument (if required)

one solenoid valve on cooling water supply line, failsafe type, energize to close,suitable for 220 V dc operation

one direct visual indicator of the bearing oil level marked in litres and high-, low-level and trip adjustable alarm contacts with 220 V dc contact rating.

15 All thermometer bulbs and detectors shall be installed in dry wells.

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TM-1 Turbine

16 Turbine bearing oil lubrication system shall be designed to provide sufficient oil

circulation and cooling for all starting, running and stopping conditions met in normal

operation, fault conditions, commissioning and maintenance.

17 Temperature in the bearing pads shall not exceed 60 C at the maximum coolingwater temperature.

TM-1.29 Lubricating Oil

Type of oil is specified in TG-17.

TM-1.30 Shaft Water Seal

1 A water seal shall be provided below the bearing which shall prevent the leakage ofwater along the shaft. The shaft seal shall be arranged for water lubrication. Two or more

connections for water shall be provided, evenly spaced on the periphery to admit a supply of

clean water at a pressure sufficient to exclude foreign matter from the seal. Any leakage

water from the seal shall be removed by drains. The seal shall be so arranged that it may beserviced without disturbing the bearing or unwatering the draft tube. For its base bid the

Contractor shall include a packing type seal similar to the existing seal on Units 1,3 whichconsists of a packing box located in the head cover below the turbine guide bearing oil pot. Itis supported on the head cover and is adjustable by tightening a gland that compresses the

sealing elements. The sealing elements are two groups of square, flexible lead impregnated

cord separated by a bronze Hring, which is used as a chamber into which water is admitted tolubricate the packing. For Unit 2, the sealing elements shall employ PTFE or similar rather

than lead. The Contractor shall provide the change in pricing for substitution of the packing

type seal with a self-aligning, balanced split face type seal. The seal shall be self-

compensating for wear, with seal water injected directly between the mating faces and allwetted surfaces of corrosion resistant materials. All fasteners shall be stainless steel. Wearing

faces shall incorporate a wear indicator.

2 A secondary sealing device shall be provided below the main seal to allow the

packing to be serviced. This device shall be interlocked with the unit automatic startingsystem to prevent start-up when in use. This secondary sealing device shall prevent leakage

along the shaft when the turbine is stationary and subjected to tailwater pressure and shall be

inflated by compressed air. The Contractor is advised that service air is available for thispurpose. The Contractor shall supply and install the necessary pressure reducing station and

all associated piping.

3 Suitable devices, such as lifting bolts and backing-out studs, shall be provided to

facilitate installing and removing shaft seal parts.

4 Water for the shaft seal shall be cooling water drawn from the same source as that for

the guide bearing.

5 A shaft water seal flow transducer 4 to 20 mA with direct reading instrument shall be

provided in the water supply piping to the seal. A 150 mm duplex pressure gauge shall be

provided for indicating the pressure beneath the seal and in the supply line.

6 The Contractor shall provide the necessary water filtration equipment, piping and

valves, including pressure reducing valves, piping and fittings within the turbine pit

terminated by Victaulic couplings, unions or flanges at the connection to embedded piping.

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TM-1 Turbine

Filtration shall remove particles larger than 25 m and shall be provided with automatic

backwash equipment with controls, and shall be sized to ensure continuous maintenance-free

water supply to the shaft seal. Piping shall be provided with a sufficient number of Victauliccouplings or unions to permit ease of removal. All piping and fittings shall be stainless steel.

7 All bolts, nuts, screws and hardware used in connection with the shaft water seal shall

be of stainless steel.

8 The shaft seal housing shall be made of steel with corrosion resistant surfaces where

required to ensure proper operation and easy maintenance of the whole assembly.

TM-1.31 Guide Vanes and Operating Mechanism

1 The turbine shall be equipped with one set of stainless steel guide vanes. The Bidder

shall submit a base Bid using cast construction but may offer fabricated construction as an

alternate. The Bidder may also submit an alternate of carbon steel construction with stainlesssteel overlay. The guide vanes shall be uniform in shape and their cross sections shall be such

as to direct properly and accelerate gradually the water entering the runner with a minimum

of friction and hydraulic disturbance. The guide vanes shall have a self-closing tendency overthe greater part of their operating range.

2 The number of guide vanes and the number of runner vanes shall be coordinated in a

manner to ensure that the turbine will operate without objectionable vibrations.

3 The guide vane material shall be cast stainless steel in accordance with ASTM A743,

Grade CA 6NM. Each casting shall be fully examined by MT and UT at the stem to guidevane fillets.

4 If of welded design, the billets for the stems shall be ordered sufficiently large to

permit the guide vane stems to clean up during machining without first having to weld up

scarf marks left by the steel mill. Each side of each guide vane shall be formed of one plate

for the purpose of maintaining a uniform contour and reducing friction. Fabrication detailsshall be accepted by the Engineer before the alternate welded design will be accepted.

5 The guide vanes shall be accurately machined and ground to a smooth finish and even

surface. The tips and contact surfaces shall be machined to template in such a fashion as to provide for uniform contact when in the closed position. All guide vanes shall be

interchangeable. At least one guide vane shall be drilled through to provide a drainage hole

(see TM-1.20).

6 The guide vanes shall be carefully fitted along the line of contact during shopassembly within 0 mm to 0.05 mm maximum clearance to ensure minimal leakage when they

are closed against headwater pressure.

7 Each guide vane shall be provided with self-lubricated guide bearings in the bottomring and head cover. The intermediate stem bushing shall be provided with V-type packing.

8 Each upper guide vane stem shall be provided with a self-lubricated thrust bearing orcollar. Positive means shall be provided to permit the vertical clearance of the guide vanes to

be adjusted from above the head cover. Wear washers are not acceptable.

9 Guide vanes, stems, links and operating rings shall be designed to produce a

minimum of lost motion and friction. The guide vanes shall be connected through couplings,

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links and levers to the guide vane regulating ring. The link pins shall be of the eccentric type

with at least 6 mm eccentricity to facilitate adjustment. During tower assembly and before

dowelling of the guide vane stems, the eccentric pins shall be set in such a way that all of the6 mm adjustment is available to the Employer for future adjustment. The design shall be such

that repairs and replacements can be easily and quickly made with minimum dismantling of

the turbines.10 The guide vane regulating ring shall be made of cast steel or welded steel plate withall welds full penetration and stress relieved. The guide vane regulating ring and guide vane

mechanism shall be so designed as to remain undisturbed when dismantling and replacing the

main guide bearing and accessories.

11 The guide vane operating mechanism shall be of ample strength and power to operatethe guide vanes and to withstand the maximum load that can be imposed on it by the most

severe operating conditions. All parts having relative contact in motion shall be provided

with self-lubricated bushings.

12 A suitable shear pin or breaking link shall be provided between each guide vane stem

and the regulating ring and shall be strong enough to withstand the maximum normaloperating forces, but which will break or release in the event of excessive forces acting in

either the opening or closing direction and will protect the rest of the mechanism fromdamage in case one or more of the guide vanes become blocked.

13 Stops shall be provided to limit the angle of movement of the guide vane stem levers

in case of breaking of the shear pin or link so that interference of the loose guide vane with

operation of the other guide vanes will be prevented.

14 As a precaution against damage when a guide vane is free to rotate due to breakage ofa shear pin or link, the guide vane levers shall be restrained from excessive movement by

means of a friction device located on the guide vane stem which provides a restraining force

between the guide vane coupling and lever. The friction device shall be designed to resistindependent movement of the guide vane for the maximum hydraulic torque at any guide

vane position. The friction device mechanism on each guide vane shall be tested during

installation to ensure performance as designed. The Bidder shall offer a price reduction fordeletion of the friction device.

15 A manually adjustable stop shall be incorporated, with which the motion of each

guide vane in the opening direction can be positively limited.

16 An alarm feature shall be provided so that a circuit shall be broken in the event that

any one of the shear pins fails. Connectors shall be provided at each shear pin to facilitaterepair of the alarm circuit in the event of failure. The alarm circuit shall be protected from

damage by flexible or rigid conduit where appropriate. It shall be terminated at a junction

box on the wall of the turbine pit for connection to external circuits. Each replacement shearpin included in spare parts inventory shall be wired ready to connect into the alarm circuit.

17 Exposed surfaces of the operating ring shall be painted to system 4, TG-14.

TM-1.32 Servomotors

1 The turbine shall be provided with two oil pressure operated double-acting hydraulic

servomotors having a combined capacity sufficient to supply the maximum force necessary

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to operate and hold closed the guide vanes, under maximum operating head, at the minimum

oil pressure. The servomotors shall be designed for the maximum allowable working

pressure of the governor system.

2 The servomotors shall be rigidly supported from the stay ring on pedestals or from thepit liner and shall be capable of moving the guide vanes from a completely closed position to

a fully open position in one stroke and vice versa. The servomotors shall be recessed into thepit liner so that the head cover can be removed without disturbing the servomotor cylinders.

3 The servomotor cylinders shall be made of cast steel or welded steel plate. Weldsshall be full penetration and stress relieved.

4 The servomotor piston rod shall be provided with self-lubricating bushings. The

piston rod shall be arranged for adjustment of stroke. The piston rod shall be coated with

hard industrial chromium of not less than 0.3 mm thickness or suitable ceramic. Theconnecting rod pins shall be hardened and ground. Cushioning shall be provided over the last

10% of stroke in each direction.

5 The inner surface of the cylinder shall be bored to a uniform diameter and shall have

a surface of 1.6 m Ra or better to allow the piston to traverse freely and smoothly and toreduce oil leakage past the piston to a minimum. Chevron type packing shall be used to

prevent oil leakage from the cylinder past the piston rod. The piston connecting rod shall be

of forged steel of uniform diameter. Each piston shall be fitted with not less than three pistonrings, suitably shaped to give close contact and uniform pressure on the cylinder walls. The

servomotor cylinders shall be provided with flanges for connecting oil piping. Connections

for pressure gauges shall be provided at each end of each cylinder. An air vent and a draincock shall be provided on each servomotor for air release and oil draining. Outlet of each

shall be provided with a plug.

6 The servomotor cylinder shall be designed and located so that the force for moving

the turbine guide vanes shall be divided approximately equally between the two cylindersand shall be applied in substantially equal magnitude to opposite sides of the guide vane

regulating ring and tangentially to the ring.

7 Provision shall be made for adequate field alignment of the servomotors using

leveling or dutchmen plates supplied by the Contractor. The servomotor flange shall bedowelled in the field to its mounting flange.

8 A manual locking device of a simple construction to permit locking the guide vanes

in either the open or closed position and capable of withstanding safely the full operating

force of the servomotors shall be provided at the servomotors. The device shall be such that itcan be easily engaged and disengaged by one man. Electrical contact switches suitable for

indication for 220 V dc system shall be provided to indicate guide vane lock in the fully open

and fully closed positions. An additional contact for unit start interlock shall be provided. Allcontacts shall be wired to terminal blocks in the turbine terminal box.

9 Bypass connections, equipped with orifices and/or adjustable needle valves, with a

secure means of locking the adjustment, shall be provided on the servomotors to retard the

rate of closure of the guide vanes slightly below speedno- load to the fully closed position.The bypass connections shall be fitted with check valves to prevent sluggish movement on

opening the guide vanes from the fully closed position.

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10 A suitable pointer and scale, graduated in tenths with subdivisions, shall be provided

at the servomotors to indicate the percent stroke of the servomotor and guide vane angle in

degrees from the closed position. The scale shall be calibrated in the field and marked`closed' at one end of the scale and `opened' at the other end.

11 Each servomotor shall be fitted with a stroke limiter which is capable of manual

adjustment. Means for positively locking the adjustment shall be provided.

12 The servomotors shall be painted on the outside as described in TG 14, Painting

System No. 4.

13 Servomotors shall be pressure tested according to TG-18.

TM-1.33 Turbine Pit Liner, Walkways, Platforms and Stairways

1 A pit liner of heavy steel plate, with servomotor pockets, shall be provided. It shall be

made in sections with bolted or welded connections as necessary for shipment. The bottom

shall be prepared for welding to the stay ring with full penetration welds or provided with aflange machined and drilled for dowelling and bolting to the stay ring. The vertical pit liner

volume 2 -sectionb tm rev 2 rfk update 11-19-04

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