dibn tfv00 0000 prs technical description turbine

7/30/2019 DIBN TFV00 0000 PRS Technical Description Turbine

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Dibbin H.E. Project (120 MW),Electro Mechanical Works – EPC Contract PackageKSK Dibbin Hydro Power Private Limited, West Kameng,Arunachal PradeshIFB No. : KSKDHPPL – 1360105 – E&M – 01 Dated : 16-05-2011

Offer Ref. No.: VHN – 11 – 001 RO

Technical DescriptionFrancis Turbine

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TABLE OF CONTENTS

1. Scope of Supply.................................................................................................................................... 3

1.1 Supply limits with civil work.................................................................................................................... 3

2 General Information................................................................................................................................ 3

2.1 Design Parameters................................................................................................................................ 3

2.1.1 Main Data......................................................................................................................................... 3

2.1.2 Operating Conditions.......................................................................................................................... 3

2.1.3 Output and Efficiency.......................................................................................................................... 4

2.1.4 Hydraulic Engineering Codes.............................................................................................................4

2.2 Design and Construction Requirements................................................................................................4

2.2.1 General............................................................................................................................................... 42.2.2 Applicable Standards and Codes....................................................................................................... 5

2.2.3 Allowable Stresses and Load Cases.................................................................................................. 5

2.2.4 Surface Finish.................................................................................................................................... 6

2.2.5 Painting and Surface Treatment........................................................................................................ 6

3 Equipment Description........................................................................................................................... 6

3.1 Runner................................................................................................................................................... 6

3.2 Shafts.................................................................................................................................................... 7

3.2.1 Turbine Shaft..................................................................................................................................... 7

3.2.2 Couplings........................................................................................................................................... 7

3.3 Inlet Parts............................................................................................................................................... 8

3.3.1 Spiral Case with inlet pipe .................................................................................................................8

3.3.2 Stay Ring and Support Ring ............................................................................................................ 9

3.3.3 Pit Liner.............................................................................................................................................. 9

3.4 Distributor............................................................................................................................................ 10

3.4.1 Wicket Gate and Bearings................................................................................................................10

3.4.2 Wicket Gate Mechanism with Operating Ring..................................................................................11

3.4.3 Servomotor...................................................................................................................................... 13

3.4.4 Head Cover...................................................................................................................................... 13

3.4.5 Bottom Ring .................................................................................................................................... 14

3.5 Shaft Seal............................................................................................................................................ 15

3.5.1 Operating Seal (Hydrostatic)............................................................................................................ 15

3.5.2 Standstill Seal.................................................................................................................................. 16

3.6 Draft Tube............................................................................................................................................ 173.7 Bearing................................................................................................................................................ 18

3.7.1 Guide bearing ................................................................................................................................. 18

3.8 Accessories.......................................................................................................................................... 19

3.9 Installation Device................................................................................................................................ 19

4 Materials................................................................................................................................................ 19

5 Spare Parts............................................................................................................................................ 20

6 Tests....................................................................................................................................................... 20

6.1 Shop Assembly and Tests....................................................................................................................20

6.2 Field Tests............................................................................................................................................ 20

6.3 Field Efficiency Tests........................................................................................................................... 20

7 Operation and Maintenance.................................................................................................................21

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1. Scope of Supply

This proposal document provides an overview to the works and services performed by Voith

Hydro. Particular emphasis is given to those aspects of the product scope which demonstrate

the superiority of many of the special features incorporated into today’s design.

The turbines will be complete with spiral case, stay ring, pit liner, head cover, Wicket gates with

operating mechanism, bottom ring, draft tube, runner, shaft, shaft seal, guide bearing, and

accessories.

Supports, stiffeners and other packing material necessary for transportation and erection are

included.

Special tools and devices required for installation, disassembly and maintenance of the

equipment will be supplied as well as piping, instrumentation, cabling and wiring.

The scope comprises design, manufacture, shop testing, transportation, erection at site, site

testing, commissioning and reliability run of the unit.

The documentation of supplied equipment contains assembly drawings, calculations, as-built

drawings and operation & maintenance manuals.

1.1 Supply limits with civil work

Aligning, fixing and bracing of turbine structures and parts which will be embedded and/or

grouted in different concrete stages are included in the turbine scope of supply.

Concrete and grouting material for embedment of all components, i.e. supply, placement,

monitoring and verification of the concreting process is responsibility of the civil works

contractor.

Piping to be embedded in the concrete for pressure measurement and Winter-Kennedy-

connections are included.

2 General Information

2.1 Design Parameters

2.1.1 Main Data

For main data see document - “Technical Data Sheets” (GTP).

2.1.2 Operating Conditions

For operating conditions data see document - “Technical Data Sheets” (GTP).

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2.1.3 Output and Efficiency

For turbine output and efficiency data see document - “Technical Data Sheets” (GTP).

2.1.4 Hydraulic Engineering Codes

• International Code for Hydraulic Turbines, Storage Pumps and Pump-Turbines - Model

Acceptance Test, IEC Publication 60193 (1999)

• Field acceptance tests to determine the hydraulic performance of hydraulic turbines,

storage pumps and pump-turbines; IEC Publication 60041 (1991)

• Cavitation Pitting Evaluation in Hydraulic Turbines, Storage Pumps and Pump-Turbines;

IEC Publication 609 (1977)

2.2 Design and Construction Requirements

2.2.1 General

The turbines will be of the Francis type with vertical shaft arrangement. The turbine is designed

to run safe and stable considering multiple daily start-stop-cycles.

The turbines are rotating counter clockwise when seeing from top. The turbine shaft is directly

coupled to the generator shaft.

The power unit will be equipped with three guide bearings, one close to the runner on the head

cover, other below the generator and third on top of the generator.

The thrust bearing, for carrying the weight of the rotating parts of the turbine and the generator

as well as the hydraulic thrust, will be part of the generator.

The uniform water inlet to guide apparatus is performed by a full spiral case with stay ring and

stay vanes. The water discharge from runner to tail race is done by an elbow-type draft tube

with steel lining up to the location where flow velocity of 4m/s arises. Thereafter, liner shape will

be formed in the concrete as per the suppliers drawing.

The flow is regulated by Wicket Gates operated by two servomotors supported on the civil

structure of the turbine pit. Reliable operation including Safe closing of the Wicket gates shall be

achieved by a nitrogen/oil pressure accumulator.

The turbine will be designed and constructed to provide clearances for axial movement of its

rotating parts as required by the generator design for inspection, adjustment and dismantling of

the thrust bearing.

The maximum turbine internal pressure resulting from pressure surge and water hammer for

emergency closing of the units against the maximum flow at maximum head water level will be

calculated. The design pressure for spiral case, stay ring, head cover, distributor and other pressure parts will be equal to the calculated maximum internal pressure.

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For the arrangement of the turbine please refer to the drawing - Cross section - Turbine (2734-

510232)

For further technical data refer to “Technical Data Sheets” (GTP).

Design modifications (if any) and improvements/optimization wherever required shall be

discussed and carried out during detail engineering of machines by Voith after necessary

approval from the customer.

2.2.2 Applicable Standards and Codes

The standards, codes and manuals cited throughout this technical description are used to

establish the level of safety, precision, quality, class of materials, acceptability, tolerances etc.,to which the work is to be performed. Where these are cited, the latest revision or edition will

prevail. Other standards, codes and manuals that will provide an equivalent level of safety,

precision, quality, class of materials, acceptability, tolerances, etc. may be substituted.

Specific standards, codes and manuals are referred in the appropriate parts of this specification

documents. Following is a list of references to sources for some general codes and manuals

cited in the specification documents.

IEC and ISO are the leading Standards.

● ANSI - American National Standard Institute

● ASTM - American Society for Testing and Materials

● ASME - American Society of Mechanical Engineers

● AWS - American Welding Society

● AISC - American Institute of Steel Construction

● ISA - Instrument Society of America

● VDE - Verband Deutscher Elektrotechniker

● DIN - Deutsche Institut für Normung

● IS - Indian Standards

● ISO - International Standardization Organization

● IEC - International Electro-technical Comission

● NEMA - National Electrical Manufacturers Association

● IEEE - The Institute of Electrical and Electronic Engineers, Inc.

In addition to the application of many international accepted standards Voith turbines are

subject to several internal standards, which are more detailed and more specific for hydraulic

machines than contemptible general standards.

2.2.3 Allowable Stresses and Load Cases

The turbines will be able to withstand all stresses arising in continuous operation or occurring

occasionally without being endangered or damaged.

The turbine components will be sized in accordance with the proven Voith internal “TurbineDesign Guidelines”, on which our components’ design and dimensioning is based. This internal

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standard defines precisely the allowable stresses for different load cases and takes into

consideration the availability of finite element calculations.

The Voith Hydro standard for allowable stresses and the definition of the loading cases are

summarized in document “Summarization of Design Guidelines of Allowable Stress Levels for

Turbine and Butterfly Valve”.

2.2.4 Surface Finish

All surfaces of the turbine water passage area will provide a smooth-contoured hydraulic

surface.

The surface finish roughness will be indicated on the component drawings and Voith standards

will be at least in accordance with ISO 4287, Roughness comparison specimens.

2.2.5 Painting and Surface Treatment

All equipment furnished and installed will be completely painted for final use, with the exception

of those parts or surfaces that are specifically designated as unpainted.

Surfaces to be painted will receive the preparatory treatment and coating according to Voith

Hydro Technical Group Standards - “General Application for Paints, Coatings and related

materials in Hydro Power Plants”. (Attached along with offer)

All paint materials, supplies and articles furnished will be standard products of recognized

reputed manufacturers.

The paint used for touch-up in the field will be of the same quality and colour as used in shop

painting. The touch-up painting will be done with material corresponding to each coat shown in

the painting schedule.

3 Equipment Description

3.1 Runner

The runner will be cast welded of high strength stainless steel composed of 13% chromium and

4% nickel and will consist of the crown, the blades, the band and the labyrinth rings. The runner

cone will be an integral part with the runner crown. The rotating labyrinth rings will be bolted with

the runner.

Numerically controlled machining of runner entrance and discharge creates perfect hydraulic

passage. Runner inspection and quality control regarding hydraulic surface are according to

IEC 60193. The surface finish of the hydraulic passages will be ground smooth to minimize the

hydraulic friction losses.

The runner will be designed to allow axial movement.

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The runner will have a bolted flange connection for attaching to the shaft.

The runner will be statically balanced according to ISO1940-1 class G6, 3. The finished runner

is supplied in one piece from the manufacturing works.

3D view of Typical Runner

3.2 Shafts

3.2.1 Turbine Shaft

The shaft will be of forged steel and will be provided with flanges on both ends suitable for the

attachment with the generator shaft at one end and turbine runner at the other end.

The turbine shaft will be designed to operate safely without excessive vibration and at maximum

torque without exceeding the allowable stresses.

3.2.2 Couplings

The coupling between runner, turbine shaft and generator will be preferably of friction type with

pre-stressed bolts. However, based on detailed calculations of transmittable friction torque, final

decision regarding type of coupling shall be discussed and agreed during detailed engineering.

Based on final coupling type, shaft alignment shall be decided and also discussed during

detailed engineering.

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2

3

1 1 - Crown

2 - Blade

3 - Band





3.3 Inlet Parts

The complete spiral comprises the inlet pipe, the spiral case and the stay ring.

Although the spiral will be embedded in concrete, it will be designed to withstand, without any

support from concrete, the internal design pressure, given by the water hammer calculation. The

design stresses for this condition will not exceed the maximum allowable stresses.

The spiral case together with the inlet pipe and the stay ring will be pressure tested at site prior

to concrete embedment. Bulkhead for inlet pipe will be supplied.

Embedment will be done with partial internal pressure (approx. 50 % of static head).

The spiral case will be dewatered by a piping system leading from the inlet pipe to the draft

tube. The piping will be opened and closed by a manual operated valve.

3.3.1 Spiral Case with inlet pipe

The spiral case will be factory welded to the stay ring assembly as far as practicable and

suitable for transportation.

The spiral case will be made as a welded steel plate construction. The spiral case will be

designed for fabrication in radial sections. Field joints will be kept to a necessary minimum in

order to allow transportation of the maximum possible assembly. The use of longitudinal joints

between spiral case plates will be avoided as far as practicable. Where longitudinal joints are

necessary, their location will be carefully selected to facilitate welding and weld examination.

The connection joint between the spiral case and the inlet pipe will be field welded. Sufficient

adjustment allowance will be provided to align the segments before field welding.

All necessary stiffener rings, pads or brackets and connections for the application of jacks and

tie rods during field erection will be supplied. These appendices will be designed to support and

position the spiral case during all conditions of installation and concreting. The spiral case will

rest on solid foundation and bracing during embedment.

Four pressure taps with pipe connection will be installed on the inlet section of the spiral case,

suitably located and arranged for head measurements and for connection to the spiral case

pressure gauge.

The pressure taps with pipe connection will be installed at points where conditions are most

favorable for measurement of flow. The type, number, construction and location are as to meet

the requirements of the Winter-Kennedy method of determining discharge, for use in index

tests.

A spiral case drain connecting the lowest point of the spiral case extension with the draft tube

will be provided. The piping will be flanged on-site to the prepared spiral case drainageconnection.

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3.3.2 Stay Ring and Support Ring

The stay ring will consist of the upper and the lower ring shaped deck, connected by the stay

vanes forming a rigid tie across the throat of the spiral case. The streamlined stay vanes will be

of suitable number. The stay vanes will be shaped and positioned to guide the water to the

Wicket gates.

The stay ring will be made of steel; either integrally cast or fabricated of plate and/or cast

components welded together.

It will also withstand the tension due to the internal design pressure of the spiral case.

At the bottom of the stay ring a support ring will be arranged in order to provide support during

erection and to transmit the forces into the concrete structure.

3.3.3 Pit Liner

The pit liner will be made as a welded steel plate construction. Field joints where necessary, will

be kept to a minimum in order to allow transportation within transport limits. The connection joint

between the pit liner and the stay ring will be field welded. The pit liner serves as steel cladding

of the turbine pit. It will have recesses for two servomotors for driving of wicket gate mechanism

of the distributor.

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3.4 Distributor

3D view of Typical Distributor

1 - Bottom Ring 4 - Operating Ring

2 - Wicket Gate 5 - Servomotors

3 - Head Cover

The distributor will consist of a suitable number of moveable Wicket gates, each consisting of a

streamlined body with stems supported through the bearings on to the head cover and thebottom ring. The Wicket gates will control and guide the water to the runner. The gates will be

linked via levers and links to the operating ring which will be operated by 2 oil-servomotors. The

anchorage of the servomotors is supported in the turbine pit. The gate locking arrangement

provided will ensure the position of the Wicket gates for maintenance purposes.

3.4.1 Wicket Gate and Bearings

The Wicket gates will be high strength chrome-nickel (13% chrome, 4% nickel) stainless steel

castings with integral stems. Each gate is supported in 3(three) self-lubricating guide bearings,

1(one) located in the bottom ring in a removable cartridge and 2(two) in a removable cartridge

block in the head cover together with the trunnion seals. The cartridges allow a fast disassemblyduring maintenance services.

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1

2

3

4

5





3D view of Typical Wicket gate with bearing

1 Bottom bearing 4 Gate lever 2 Wicket gate 5 Top bearing3 Middle Bearing

3.4.2 Wicket Gate Mechanism with Operating Ring

The wicket gate mechanism will consist of the gate levers, bending links, operating ring and

gate servomotors with anchorage.

The gate lever will be firmly attached and dowelled to the wicket gate stem. A bending link

between the lever and operating ring will transfer the force for all considered operation loads.

The operating ring is actuated by two servomotors and will distribute the forces and movements

to all of the Wicket gates simultaneously.

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2 1

11

31

41

5 1





Sketch of Typical Lever and bending link arrangement

In case of foreign object is jammed between the closing edges of two consecutive wicket gates,

two wicket gates can’t be closed. In order to protect the linkage and the gates and so as to

avoid possible cascade failure, the two related bending links will be subject to plastic

deformation due to the excessive force while distributor is closing. After removing the jammed

object, the deformed bending links have to be replaced. Due to the use of the bending linksthere is no other damage caused. The major advantage of the gate mechanism with bending

link is that the wicket gate will never be free and collide with rotating runner because even after

the related bending link undergoes plastic deformation, remains attached with operating ring.

Each gate link shall be provided with one limit/proximity switch to provide indicating signal for an

occurrence of bending link deformation.

Schematic of bending link plastic deformation

The operating ring shall be supported on head cover through axial and radial self lubricating

bearings. The sliding surfaces of operating ring with the bearings shall be of stainless steel. The

operating ring shall be designed to withstand rigidly the unbalance forces from servomotor as

well as in event of bending link(s) failure.

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Plastic deformation of Bending

Link due to excessive force.

Excessive force from Servomotor through Operating

Ring due to jammed object between wicket gates.





3D view of Typical Operating Ring.

The position of the operating ring will be monitored by limit switches. For visual check a position

scale will be installed on the operation ring and the head cover.

All gate mechanism bearings will be self-lubricating bushings.

3.4.3 Servomotor

Double-acting, oil-pressure operated hydraulic servomotors will be supplied, provided with

connections for the oil piping.

The servomotors will provide the necessary forces to maintain the distributor in different openingpositions as required by the turbine regulating system during operation and to safely close the

distributor under any operating condition of head and load.

One number of linear transducer shall be mounted on one of the servomotors to get feedback of

servomotor guide vane movement.

The servomotor support will be integrated with the pit liner. The reaction from the servomotor

will be transmitted to the surrounding concrete.

For the safety during maintenance, the gate locking arrangement, capable of withstanding full

operating force from servomotor, shall be provided for locking of the wicket gates in fully openand fully closed positions.

3.4.4 Head Cover

The head covers will be fabricated from steel plates. It will be of rigid construction, substantially

ribbed and designed to minimize deflections and vibration and to prevent distortion and

interference with the wicket gates and the gate operating mechanism under the maximum water

pressure and other forces acting including those from turbine guide bearing.

The head cover will be bolted to the machined flange of the stay ring upper deck using a

stationary seal which will seal against the stay ring upper deck.

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3D model of typical head cover

The head cover will support the turbine guide bearing and shaft seal.

Provisions will be made for lifting the head cover in one piece from the turbine pit through the

generator stator bore by the power house crane.

Thrust relief pipes are attached to the head cover in order to minimize the hydraulic thrust on

the runner.

Sufficient clearance for moving the runner axially will be provided.

The head cover will contain the removable cartridges for the bearings and seals of the upper

wicket gate stems.

Suitable drainage passages along the nose vane will be provided in the head cover to permit

leakage water from the seals to the drainage system. Additionally, a headcover drainage pump

with all accessories will be supplied to remove any water collecting in the lower part of the head

cover.

The head cover will also be equipped with a stationary wearing ring as a counter-part to the

upper runner labyrinth seal. In the area adjacent to the wicket gate end surfaces, stainless steelfacing plates will be provided on the head cover.

3.4.5 Bottom Ring

The bottom ring will be fabricated from steel plates

The bottom ring will be flanged to the lower deck of the stay ring. The bottom ring will contain

the cartridges for the bearing and seal of the lower wicket gate stems. The bottom ring will be of

enough strength and stiffness, that the maximum deflection will not interfere with the wicket

gates or reduce the gaps of bearings to inappropriate values.

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The bottom ring will also be equipped with a stationary wearing ring as a counter-part to the

lower runner labyrinth seal.

In the area adjacent to the wicket gate end surfaces, stainless steel facing plates will be

provided on the bottom ring.

3.5 Shaft Seal

The shaft sealing system will comprise the operating seal and the standstill seal, intended to

prevent water from entering to the turbine pit, through the shaft / cover clearance.

3.5.1 Operating Seal (Hydrostatic)

A water sealing system of the self-compensated hydrostatic axial type will be designed around

the shaft, positioned below the lower guide bearing, to limit the water leakage between the head

cover and the shaft.

3D view of Typical Shaft Seal

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10 8 7

1

2

6





1 - Water collecting pan2 - Support ring

3 - Holding/retaining ring

4 - Compression spring

5 - Indicating pin

6 - Seal ring

7 - Seal ring inserts

(synth. material impregnated

with molybdenum)

8 - Sliding ring

9 - Shaft

10 - Stand still seal

The hydrostatic operating seal consist basically of a seal support ring, a static seal ring with a

synthetic seal ring insert and a metallic sliding ring (fixed to the turbine shaft). The static seal

insert will axially seal against the sliding ring. Filtered water will be fed into the seal ring insert

chamber between the two seal surfaces and creates a water film which acts as a hydrostaticbearing separating the rotating sliding ring and the stationary seal ring. There is no physical

contact between the two rings and therefore theoretically no wear occurs. Flushing purified

water will prevent any sand from entering the shaft seal surfaces, so that the wear rate for the

seal ring is very low.

The seal ring is pressed against the sliding ring by a number of stainless steel springs which

also ensure the seal function if the unit is at standstill and the lubrication water supply is

switched off. The seal is able to move axially. The diameter of the seal ring is designed to

equalize forces from the water pressure acting on the seal ring; therefore the seal is not

sensitive to changing water pressures. The seal support will be bolted to the head cover.

The design will allow the inspection and replacement of the sealing components.

A wear indication for the seal ring insert shall be provided to supervise the wear, without the

disassembling of any part of the sealing housing.

3.5.2 Standstill Seal

The standstill seal will be installed between the water passage and the Operating seal. It is

intended to protect the operating seal during extended periods of standstill.

The standstill seal consists of an inflatable rubber profile which applies to the shaft whenpressurized, thus sealing off the water passage. When being relieved, the water pressure of the

water passage pushes back the sealing lips from the shaft.

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Schematic view of Typical Shaft Seal





The seal must be applied only when the turbine is stopped. It is applied manually by operatingthe control valve. A limit switch on the operating valve prevents the turbine from being started,

when the standstill seal is applied. The operating valve will be secured with a padlock.

The air to inflate the standstill seal will be taken from the compressed air system. If necessary a

pressure reducing valve will be provided to reduce the air pressure to a value applicable for the

standstill seal.

3.6 Draft Tube

The draft tube will be of the elbow type. The draft tube will consist of the draft tube cone, the

draft tube liner and the concrete portion. The draft tube cone will be bolted to the bottom ring atupper side and to the draft tube liner at lower side.

The draft tube lining will be a welded steel plate assembly. To facilitate transportation it may be

sectionalized for field welding. Because of its rigid design with outside stiffening rings and ribs

and concrete reinforcements the draft tube will withstand safely pressure variations and

pulsations under all operation conditions.

The draft tube liner will have a suitable number of pads and connections for the application of

jacks or leveling screws and tie rods for anchoring during field erection. The draft tube will have

a steel lining until the location where flow velocity of 4m/s arises. From there the draft tube will

be shaped in concrete according to the requirements given by the hydraulic neat line.

The draft tube will rest on solid foundation and bracing during embedment. Fixations will be

designed to support and position the draft tube during all conditions of installation and

concreting.

The cone will be split in two parts with dismantling joint to facilitate runner removal from bottom.

The draft tube cone will also provide access to the draft tube inside via a man-door to enable

inspection and maintenance service. The inner surface of the man door cover will conform to

the interior contour of the draft tube liner. A test cock will be provided below the sill of the door.

The upper portion of the draft tube cone directly below the runner will be made from stainlesssteel with an extension of approx. 650 mm.

A drain box will be made at the lowest point of the draft tube, protected by a suitable and

removable inlet grating. A connection for the spiral case drain pipe will be provided.

One set of pressure taps with pipe connection will be installed.

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3.7 Bearing

3.7.1 Guide bearing

The turbine guide bearing will support the turbine shaft and will be designed for radial forces

originated from the turbine runner. The radial forces will be transferred via bearing housing,

head cover and stay ring into the civil structure.

The turbine guide bearing will be of the segmented, adjustable, multiple-shoe, self-lubricated

type. The shaft is running on the bearing pads. The segments are machined in a way to self

adjust to the optimum position with respect to load and circumferential speed.

The bearing elements are lined with a high-grade anti-friction Babbitt metal securely anchoredto the bearing backing.

The guide bearing will be located above the shaft seal and will be as near as possible to the

runner and will consist of a bearing support or housing and removable bearing elements.

It will permit axial movement of the shaft.

Fig. 11- Typical 3D section view for turbine guide bearing

01 - Segment Support 06 - Oil Pan Cover

02 - Oil Pan 07 - Support Ring

03 - Splash Ring 08 - Seal Ring

04 - Bearing Pad 09 - Oil Cooler with Piping

05 - Oil Discharge Pipe 10 - Seal Washer

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1

2 34

5

6

7 8

9 10





The oil circulation will be of the self-pumping type by the action of the rotating oil pan mountedon to the turbine shaft. An oil reservoir of sufficient capacity to contain all the oil required by the

bearing lubrication system is provided around the bearing. The bearing reservoir is an integral

part of the bearing housing.

Cooling of bearing oil will be done by an external cooler as well as air cooling due to the

convective heat transfer from rotating oil pan surface to the ambient air. Such air cooling is an

added advantage of this type of bearing. This air cooling effect is always available when water

cooling stops due to cooling water failure which decrease rate of temperature rise.

3.8 Accessories

Working, operating and inspection walkways and platforms complete with non-slip type floor

plates, stairs, ladders and hand railings will be furnished where necessary or desirable in the

turbine pit. All pit walkways, platforms, stairways and equipment will be easily removable.

A circular manual hoist will be supplied inside the turbine pit, for assembly and disassembly of

turbine components. The hoist girder will be located below the generator lower bracket and will

be integrated by a manual chain hoist, a manual trolley and a steel structure that allows the

movement of the hoist over the entire turbine pit area.

A runner trolley will be supplied to facilitate runner removal from bottom side.

An inspection platform will be furnished to facilitate inspection and maintenance of the runner.

The platform will extend over the cross-sectional area of the draft tube where it is installed. It will

be made of prefabricated, light weight components in suitable sections so as to be easily

transported into the draft tube. Provisions will be provided on the draft tube cone for supporting

the maintenance platform.

Parts for pressure tests will be included in the scope of supply as far as required for field tests.

Oil for first filling of the governor pressure oil systems and for the turbine bearings with 10% as

extra will be supplied.

3.9 Installation Device

All special tools required for normal operation and maintenance will be supplied. It shall be as

per tender specifications (PTS-Turbine and accessories). However, those which are common

with other part of specifications shall not be doubled unless it necessitates for scheduled

erection and commissioning.

4 Materials

For all major parts, materials are listed in turbine datasheet submitted with bid. The materials

might be subject to changes according to market availabilities. Equivalent materials may beused. All used materials will be of accepted national or international standards and of proven

reliability for the intended purpose.

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5 Spare Parts

All spare parts to be supplied will be identical to the ones originally installed, of the same

material and manufacture process. All spare parts will be packed not to be damaged during

storage. All boxes will be marked for identification.

All applicable spare parts as listed under “mandatory spare parts” of tender document shall be

included in scope.

6 Tests

6.1 Shop Assembly and Tests

The turbines will be assembled in the shop to verify the design, construction, machining for

proper alignment, fits and clearances to the extent practical. Parts will be properly match-

marked, identified and doweled to assure correct assembly and alignment in the field.

Critical dimensions and small clearances of the assemblies will be measured and recorded on a

shop inspection sheet.

6.2 Field Tests

The pre-commissioning tests will include, but not be limited to:

● Pressure tests on all pressure oil piping shall be done as per agreed Inspection and Test

Plan ( if not done at works).● Measurement of mechanical clearances, levels, strokes and other measurements

● Functional tests of all auxiliaries and protective devices as necessary

● Operation with governor hydraulic units.

● Functional operation of the gate operating mechanism in the dry condition

● Operational tests of turbine bearings

● Start - stop sequences test in the dry condition

The commissioning tests will include, but not be limited to:

● Alignment and rotation checks in the dry condition

● Mechanical run

● Governor operation● Guide Vane function test

● Timing tests including measurement of guide vane openings

● Initial no-load wet run to ensure satisfactory operation of auxiliary equipment

● Bearings test run

● Checking of interlocks and indications

● Tripping tests for turbine

● Load rejection and load acceptance tests

6.3 Field Efficiency Tests

A thermodynamic test at one turbine will be carried out to test hydraulic efficiency of the turbine

as per the IEC 60041.

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The power output and efficiency tests on the turbine will be made at net effective head as near

as practicable to the rated head if actual conditions allow. The turbine capacity will bedetermined from electrical measurements of generator output corrected for generator losses.

The generator losses will be determined from generator efficiency curves and verified by

measurement of air cooler and bearing heat loads.

7 Operation and Maintenance

Operation manuals and maintenance manuals will be provided before commissioning phase.

dibn tfv00 0000 prs technical description turbine

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