Erection and Site Inspection Proceedure

1. SEQUENCE OF ERECTION FOR TURBINE-GENERATOR AND ACCESSORIES:

A. Establishment of C/L & Bench mark.

B. Pier nose Liner

C. D.T. Elbow Liner.

D. D.T. Cone

E. 1st stage Foundation, embedment & pipes

F. Stay ring

G. Spiral Casing.

H. Welding & Radiography

I. Test Cylinder & Cone

J. Pressure Testing & Dismantling Test Cone & Cylinder Runner envelop & Matching Piece.

(Make up piece)

K. Concreting

L. Second stage foundation, embedment & pipes, pit liner assembly.

M. Barrel concreting, foundation pipes.

N. Rotor assembly & Stator assembly in E.B.

O. Runner assembly runner & shaft assembly pr. test. Trial assembly of G.V with pivoting &

outer Top Cover.

R. Lowering of Runner & Shaft assembly with Inner top cover final assy, of Guide apparatus.

S. Auxiliaries & Governor piping

T. Governor oil piping, G.V. Servo, piping & other Auxiliaries.

U. Feed back Mechanism.

V. Lower Bkt. Foundation stools, stator foundation stools

W. Lower bkt. assembly & lowering, Centralizing.

X. Stator lowering, Centering, Air cooler assembly, piping.

Y. Spring assembly. Thrust pad assembly, H.S. Lubrication.

Z. Lowering of shaft after, fixing servo tube.

STORAGE AND HANDLING INSTRUCTIONS

1. GENERAL

1.1.1 The instructions given here are to serve as compendium for Storage and handling of the

Hydro Turbine components.

The technology of packing and also design of components are constantly being improved

and hence the instructions given here are subject to modifications. Effort has beer, made to

cover as many aspects as can be foreseen at the moment. The aim of proper storing and

handling is to ensure trouble free erection and operation. It has been pre-supposed that the

operators and supervisors who will handle these are conversant with general engineering

practices and sufficiently skilled in material handling.

1.1.2 The following publications by British Standard Institute will be most helpful.

i) B.S. 113-1967 - Packing Code Sections 1 TO 6 and section 19.

ii) B.S. Hand Book No.4 part 1 and 2 'Lifting Tackle'.

1.2 RECEIVING AND UNLOADING

1.2.1 The components are packed for their safe transportation -from the manufacturers works to

the site and this packing is unsuitable for long time storage in open air after the packages

have reached the erection site.

1.2.2 Before unloading a packing case from the carrier the following instructions painted on the

packing case should be noted.

(i) Weight of the package.

(ii) Marking showing "THIS SIDE TOP".

(iii) Marking showing the "SLING POSITION".

1.2.3 For all major components, lifting arrangement drawings are supplied. These should be

consulted while lifting these components.

1.2.4 Suitable lifting gear should be selected. The lifting tackles which are properly certified by

appropriate authority about load carrying capacity should only be used. All tackles should

be properly maintained. If the sling marks are not provided on any of the packing for

lifting, the sling should preferably make an angle not more than 30 deg. to the vertical,

and in no case more than 45 deg., while lifting the packing.

1.2.5 Lifting should be done without jerks and impacts.

1.2.6 While handling the packing, the warnings indicated by markings and inscriptions on the

packing boxes such as "HANDLE WITH CARE". "THIS SIDE TOP" "NOT TO PUT LOAD

ON THE TOP", "SLING HERE" etc. shall be strictly observed.

1.2.7 On receipt of the equipment check them with the shipping list. Any omission and damages

should be reported back to SUPPLIER immediately. This checking should be preferably

done in the presence of SUPPLIER's representative posted at site. At the time of

inspection the case should be opened carefully so as not to destroy the packing material

in the process to that it can re re-used.

1.2.8 Protective coating applied on machined surfaces should not be disturbed. The plastic

covering should be put back carefully after inspection of the component. Some packing

cases may contain VCI (Volatile Corrosion Inhibitor) coated paper, which lets off the

vapour that prevents corrosion of the parts inside the packing case. This should not be

thrown away as long at it is effective. Absence of odour from the paper indicates loss of

effectiveness. Silica Gel and such other chemicals kept in the box as desiccants and

indicators should also be left in the box. The case should be restored to its original state

as -far as possible.

1.3 STORAGE

The equipment should be accommodated in permanent place of storage within a week after

arrival at destination.

1.3.1 The warehouse or the covered area where the equipment is to be stored should be clean,

dry and well ventilated. It must have been pretreated with pesticides insecticides against

growth of fungus and other micro-organism.

1.3.2 The cases should be arranged in neat stacks away from walls and at least 100 mm above

floor level preferably on rail sections, and also so far as possible in the sequence of

requirement of the parts for erection. Adequate gangways are to be left for inspection and

cleaning. It is also recommended to repaint weight, upright position indication etc. on the

side exposed for inspection.

1.3.3 To prevent distortion the heavy part and other large assemblies should be kept on even

platform. The articles weighing 10,000 kg and above should be arranged in a single tier.

Parts weighting up to 5,000 kg may be piled up to a height of 2.5 meters. Small and

medium size- components are recommend recommended to be stored on shelves.

1.4 GUIDE PADS

1.4.1 Guide pads supplied by SUPPLIER have thin lining (2 to 3 mm) of tin base babbit metal

chemically bonded to a steel backing. The pads are polished to high surface finish.

1.4.2 The babbit metal is quite soft and can be easily scored by ferrous material. These pads

should be stored in such a way as to prevent abrasion, scoring etc. These pads must not

be stacked one over another.

1 .5 FABRICATED COMPONENTS

1.5.1 All these items are generally fabricated from mild steel shot blasted and painted. The

machined surfaces however are treated with corrosion protective chemicals. As these

chemicals are to be removed before assembly, they are necessarily of temporary nature

and can be easily removed. Sometimes, in addition to this, aluminum foils or plywood is

used to protect against mechanical damage.

1.5.2 As soon as the components are received at side they should be examined for rupture of

preventive (TRP) film given at works. It is recommended that either a touch up work is done

or complete new film of TRP is applied.

1.5.3 It is recommended that films are replaced twice a year, preferably before and after

prolonged rainy periods.

Oil and grease do not protect surface adequately. SUPPLIER do not recommend their use

as rust preventives.

1.6 PIPE WORK

Before the pipes and pipe works are sent to site, the pipes are pickled and coated with rust

preventive coatings. Small bore pipes are plugged and large bore pipes are covered with

flanges.

1.7 INSTRUMENTS

Packing cases containing instruments, relays, motors, etc., are marked 'fragile'. Jerks and

impacts should be avoided in handling these. These cases should be fully opened and

inspected for any damage on arrival. The repair and replacement of instruments takes a

long time. It is recommended that all the instruments are checked for calibration. The

instruments should be repacked giving adequate cushioning. The instruments could also be

stored individually without the packing cases, but on properly cushioned bases and with

adequate protection against falling objects, accidental impacts etc. All instruments should

be stored in a vibration free area.

2.0 PROTECTION OF FERROUS COMPONENTS WITH TEMPORARY RUST PREVENTIVE

SYSTEM

INTRODUCTION: All components dispatched from SUPPLIER Bhopal would have been given

protection against rust by application of one of the following points. However

if any site application is necessary due to long storage, following guidelines

should be kept in mind.

2.1 Materials

2.1.1. For site use SUPPLIER recommends the following Temporary Rust Preventives (TRP).

a) Non-drying Type (Pigmented) BP 55191

b) Drying Type (Pigmented) AA 55155

c) Drying Type (Black) AA 55154

2.1.2 Non -Drying Type (Pigmented) BP 55191

This can be applied with brush resulting in soft non-drying film. This provides protection for

a period not exceeding 4 to 6 months. This can be removed with white spirit. Because on

non-drying nature of the film, it runs the risk of getting wiped off accidentally and exposing

that area to corrosion. Hence more care is required during storage.

2.1.3 Drying Type (Pigmented) AA 55155

This can be applied with brush resulting in thin dry film, which can be removed with white

spirit Xylol or Toluol. It would provide protection for a period not exceeding six months.

2.1.4 Drying Type (Black) AA 55154

This can be applied with brush resulting in a thin dry film which can be removed with white

spirit. It would provide protection for a period of 12 months. It is good for outdoor

applications.

2.2 Other materials which would be required in the process are:

a) Xylol

b) Toluol

c) Mineral Turpentine (White Spirit)

d) Derusting Solution (Rust Removal) BP 55193

3. 0 SURFACE CLEANING

Before any TRP is applied on any metal surface the surface should be free from old TRP,

rust, grease, moisture etc. It may be emphasized that the effectiveness of the TRP is

reduced or even nullified if the surface is left contaminated.

3.1 Remove the old TRP with the help of white spirit.

3.2 Remove the rust spots using sufficient quantity of derust solution rubbing with clean cloth.

Clean the surface with cloth soaked in water. In case the surface is still not clean, repeat

the process. Finally remove the residual acid from the surface with the help of wet cotton

otherwise it may cause further Corrosion.

3.3 Dry the surface with the help of hot air blower.

3.4 Wipe off the surface with clean cloth having small quantity of uncontaminated white spirit.

Allow the solvent to evaporate. The surface is now ready for TRP application.

4.0 TRP APPLICATION

The application has been classified into four categories viz., A, B, C&D keeping in view the

status of finish and extent of protection desired.

4.1 Category ‘A’

Journal faces, highly finished surfaces (better than 0.8 microns) such as thrust face,

bearing surfaces of Shafts.

4.2 Category 'B'

Large fabricated items having machined surfaces such as Guide Bearing Support Ring,

Vapour Seal Assy, Oil Retaining Sleeve, mating surfaces, shaft flanges.

4.3 Category 'C'

All fasteners and threaded portions excepting in such cases where the job has already a

protective film each as plating, galvanizing etc.

4.4 Category 'D'

Small machined components & other components not defined above.

5.0 TRP SYSTEM OF APPLICATION

5.1 Jobs classified in Category 'A' and ‘B' will have 3-coat system as detailed below.

5.1.1 After cleaning, apply one coat of TRP AA 55155 and allow it to air dry for 12 hours inside

the store.

5.1.2 Clean dust from the surface and apply a coat of TRP AA 55154 and allow it to air dry for

about 12 hours.

5.1.3 Apply second coat of TRP AA 55154 and allow it to air dry.

5.2 Jobs classified as Category 'C' will have 2-coat system as detailed below.

5.2.1 After cleaning apply one coat of AA 55154 on non-threaded portion and a liberal coat of BP

55191 on threaded portion. Allow if to air dry for 12 hours.

5.2.2 Apply second coat of TRP AA 55154 on non-threaded portion.

5.2.3 Fasteners of small size, having no other protective film such as plating, galvanizing etc.

after cleaning, shall be given a liberal coat of BP 55191 TRP on threaded and non-threaded

portion.

5.3 Jobs classified, as Category ‘D’ will have two-coat system of TRP as detailed below.

5.3.1 After cleaning apply one coat of AA 55155 and allow it to air dry for 12 hours.

5.3.2 Apply second coat of AA 55154 liberally and allow it to air dry.

6.0 PRECAUTIONS

6.1 TRP should be stirred well in the original container so as to make a homogeneous mixture

of its constituents.

6.2 Container and brush must be cleaned after application with white spirit before keeping for

next operation.

6.3 During the drying period, the wet film should be protected from, deposition of dust particles

by providing an umbrella of polythene sheet.

6.4 Protections, given for TRP film, such as Aluminum sheet, plywood etc. should be replaced

after application of the TRP. The surface coming in contact with the job should be given a

liberal coat of AA 55154.

6.5 Normally after an interval of six months, the surface of TRP coated jobs shall be examined

for any damage, corrosion spots etc. the repair should be done and TRP System applied.

6.6 All materials specified above can be ordered on SUPPLIER.

GENERAL GUIDELINES FOR ASSEMBLY AND ERECTION

1. POWER HOUSE AXIS

Customer shall provide axis of powerhouse and elevation. Established centerline and datum

shall be made available on steel plates embedded in concrete nearest to respective unit in

powerhouse.

2. CONCRETING AND GROUTING

2.1 Concreting does not come under SUPPLIER scope of work. However, customer should

ensure that following precautions are taken prior to and during concreting.

2.2 For good bonding, old concrete surface should be made rough and if required should be

chipped.

2.3 All surfaces should be cleaned and washed with air water jet.

2.4 Concreting shall be done in steps / lifts.

2.5 Concrete foundations, pedestal of equipments are to be chipped and made even to

achieve surface contact for better load transfer to foundation.

2.6 Recommended setting time is allowed before taking up further works.

2.7 During concreting, vibrator must not touch any embedded or machine parts.

2.8 Grouting wherever required shall be done from bottom upwards as slowly as possible.

Grouting pressure should not be more than specified at relevant places. Grouting shall be

stopped when grout material flows out from other grouting holes provided for each space,

surrounded by ribs.

3. MEASUREMENT AND RECORDS

3.1 All measurements shall be taken as per the checklists / log sheets of field quality

assurance and recorded.

3.2 For spiral casing with stay ring, measurement shall be taken before and after concreting.

In case of any deviation corrective action shall be taken.

3.3 Final log sheets shall be prepared at each stage of erection work and signed by

representatives of SUPPLIER and customer.

3.4 Even though erection tolerances are given, efforts shall be made to achieve best possible

results.

4. UNPACKING AND CHECKING OF PLANT EQUIPMENT

4.1 All materials shall be unpacked and checked well in advance of erection work. In case of

any damage / shortage, suitable action in line with QAM/SP shall be initiated to inform

concerned agencies. Storage and preservation of materials shall be ensured as per

manufacturer instructions.

4.2 All rubber products eg. Cup seals, O-rings etc. are preserved till their use, in chalk

powder / water container with water replacement every week / water soaked saw dust.

5. WELDING

5.1 Welding is carried out by a qualified welder.

5.2 Recommended electrodes are used wherever specified.

5.3 Edge preparation is checked / prepared wherever required as per drawing.

5.4 Surfaces are cleaned thoroughly before starting welding, surfaces must be free from

foreign materials such as grease, oil, paints etc. for a distance of at least 20 mm from weld

joint on either side.

5.5 Electrodes are suitably baked in oven prior to their use to 300 C at least for two hours / as

per manufacturers guidelines.

5.6 Proper root gap is maintained for welding to avoid undercut, over laps, abrupt ridges and

valleys.

If the gap is more than 5 mm packing strips are provided to minimize shrinking and

welding deformation. These shall be removed before starting seal welding from other side.

Preheating / post-heating of surfaces / stress relieving of weld joints is carried out

wherever necessary as per technical requirements.

5.7 After root run completion of welding dye penetrant testing is carried out and corrective

action taken.

5.8 Wherever circumferential welding is involved, welding as per sketch no. 1 is followed for

making root run.

5.8.1 Mark zone of approximately 300 to 400 mm length as shown.

5.8.2 Complete welding in various zones starting simultaneously in opposite quadrants.

5.8.3 After this, welding may done starting from two or four points and proceed

continuously. In other joints skip / step welding as shown in sketch no. 2 may be

followed to minimize deformation of equipments.

5.9 Before starting seal welding on the other side, gouging / or grinding is done and dye

penetrant is carried out.

5.10All site weld joints of stayring and spiral casing are radiographed or UT done as per

technical requirements of concerned drawing.

5.11After completion of site welding and grinding painting of effected areas is to be done.

5.12In case welding is provided in pipe works, edge preparation and welding is carried as per

drawing requirements.

6. RUBBER CORD SCARF / STRAIGHT JOINTING

6.1 Area of each groove equipments is measured / calculated. Rubber cord of 80% to 90% of

the groove area is selected.

6.2 Cut the cord as per length required including scarf / straight joint. In general it is

recommended to keep the length of cord 1% less than the actual requirement.

6.3 Prepare by cutting or / and grinding as shown in sketch no. 3.

6.4 Clean the ends and make joint with suitable adhesive, eg. Anabond, Elfy, etc.

7. USE OF LUBRICANTS

7.1 During assembly of close fitting parts, moving or sliding parts, a thin coat of grease is

applied.

7.2 On the other joints of sealing surfaces, a thin coat of white lead / hold-tite may be applied.

8. TIGHTENING OF FASTENERS

8.1 On the threads of heavy duty fasteners, it is recommended to apply a thin coating of anti

seizing compound i.e. molybendenum disulphide or graphite grease in order to prevent

scratching or seizing at the time of tightening or loosening.

8.2 While tightening the fasteners, be sure to proceed symmetrically and uniform, so that there

is no unbalanced tightening in the joint. The tightening wherever specified should be

followed. After fully tightening the fasteners these should be locked as called in the

drawing.

8.3 All thread portions and fasteners are proved in advance for checking healthier threads. If

not, rectified suitably for obtaining smooth threads.

9. ASSEMBLY OF EQUIPMENTS

9.1 Before taking up any assembly, check all items of the concerned drawing are available.

Check for any damaged components and rectify if possible after obtaining concurrence

from concerned manufacturing unit.

9.2 Check for all technical requirements of drawings to be satisfied at site and ensure their

compliance.

9.3 Check for all concessions /deviations raised at shop if any to be taken care at site and

ensure compliance.

9.4 Check for all test results of shop wherever necessary.

9.5 Check for PO number, assembly match mark and axis marking for each assembly.

9.6 Ensure that individual components are cleaned & are free from burrs and scratches.

9.7 Check for special lifting arrangements of assembly / sub assembly, if any and ensure its

availability.

9.8 Check for shop dowels.

9.9 Temporary plugs / protections provided should be retained till final assembly.

9.10Blow compressed air to oil and grease ports, load grease ports with grease and plug them

temporarily.

10. CONFIRMATION BEFORE STARTING ERECTION / ASSEMBLY WORK

10.1Confirm availability of all tools and tackles required for erection works.

10.2Confirm availability of reference drawings and technical documentation related to the

project.

10.3Confirm customers certified centre line and established datum available on embedded

plates on the concrete nearest to the pit.

10.4Confirm availability of all connected equipment’s, instruments required for erection.

10.5Ensure installation of generator assemblies with reference to Radial line of assembly.

11. PREPARATION OF FOUNDATION BLOCK OUTS

11.1Check the foundation block outs dimension and locations, if necessary carry out chipping

of foundations to required dimension and elevation.

B. Welding & Cutting

1. Use proper protective clothings, welding glass to avoid burn injuries due to welding

spatters, hot welding slag arc flashes etc.

2. Ensure proper earthing of work & welding machine to avoid electric shock.

3. Never look at welding arc without using welding dark glass.

4. Welding area should be properly ventilated to minimize air pollution in the surrounding area.

5. Fire extinguishers, sand etc, should be available nearby.

6. Store gas cylinders away from "Sources of Heat" Over Furnace, direct sun rays.

7. Store gas cylinder in well-ventilated place.

8. Use rubber hoses correctly as per coding.

9. Oxygen green or Black house. Acetylene Red hose.

10. Ensure against leakage of gas from torch, hose valves Regulators etc. Use proper pipe

clips. Periodical checking of pressure gauges of regulator to be done.

11. No flammable material like Petrol, Oils Dyes Acids Enamel paints and Varnishes etc, be

lying in the area where cutting or welding is being done.

(c) Lifting Tackles

1. Do not subject wire rope beyond safe working loads.

2. Periodic inspection of ropes and safe load testing be done.

3. Store ropes properly to avoid kinks.

4. Periodic greasing of ropes should be done to avoid rusting and decrease friction.

5. Periodic testing of 'D' shackles, turn buckles, Pull lifts and chain pulley blocks be done.

6. Avoid wire ropes coming in contact with sharp edges while lifting.

(D) Cranes

1. Never stand under heavy loads.

2. Do not keep the load suspended for more time than absolutely required. For this, plan your

activity well in advance.

3. Lifting of loads shall be started slowly and erratic movements avoided.

4. Grease the wire ropes regularly.

5. Periodic checking of electrical controls and brakes, gearbox to be done.

6. While giving signals to crane operator standard signals with which operator is conversant

be given by one man.

7. Crane should be regularly maintained as per its maintenance schedule.

(E) Rotating Small Hand Tools (Like Grinding, drilling machines)

1. Guards above moving parts should be in position.

2. Use proper protective clothing.

3. Use safety appliances like goggles hand gloves, aprons.

4. Avoid standing in -front of the wheel or cutting tool, whiie in motion.

5. Do not apply excessive pressure on cutting tools to quicken the process.

6. Tool/Grinding wheels be secured properly.

7. Correct speed be ensured of rotating wheels.

8. Ensure electric hand tools are free from electric shock.

F. Acids and Alkalies

1. Never add water to Acid for making dilute solution. Always add Acid to water.

2. Never handle any acid or alkali with bare hands and without protection to eyes.

3. Use acid proof rubber gloves, gum boots, rubber aprons and goggles as per Job

requirements.

4. Whenever there is any acid or alkali burn, wash off as quickly as possible with a large

quantity of clear water and then rush to doctor.

Embedded Parts

Embedded Pipe in First Stage

(A) Pre-Erection Checks.

(i) Check for availability of all the items as per relevant drgs & bill of material and clean

them.

(ii) Check that all the necessary tools, equipment & material required are available at

site.

(B) Erection.

(i) Pipes to be erected.

(a) Draft tube drain pipe.

(b) Spiral drain pipe.

(iii) Position above pipes as per drawing dimensions & elevations.

(iv) Weld the pipes as per details given in drawing.

(v) Ensure proper clamping of pipes so that they remain in the same position during

concreting.

(vi) Hydraulically Test the pipes as per Drawing.

Blank the open ends of the pipes with M.S plates. Tack weld at minimum 4 points to

lock.

Field efficiency test for pipes

1. Field efficiency and discharge measurements are to be made for all units as per drg.

2. Obtain datum line of penstock.

3. Bends of St. Steel pipes to be made at Site.

4. Mark Bosses on penstock DT liner / spiral casing and weld suitably.

5. Erect bend pipes and position support.

6. Pressure test pipes as per values given in drawing.

7. Clamp supports and put covers. Hand over for concreting.

8. After concreting check pipes for any blockage concreting.

9. Embedded pipes for field efficiency test

Pier Nose

1. Lower Pier nose assembly using winches wire ropes or suitable crane then check level and

elevation.

2. Use shims / packing plate for achieving required elevation.

3. Check center-to-center distance and align.

4. Fix foundation bolts and tighten.

5. Fixing of Anchors.

6. Final checking of alignment and verticality.

7. Hand over for concreting.

Tolerance: (a) Vertically 1 .mm/metre.

(b) Elevation within ± 2 mm.

Draft Tube Elbow Liner

1. Transport D.T. Knee liner segments in Sequence.

2. Check Unit Nos. Match marks etc.

3. Check level of pedestal/ Steel supports.

4. Lower bottom most - segments and match.

5. Arrange all bottom, top, left side, right side segments and assemble them complying with

elevation w.r.t. relevant drgs.

6. Stich welds assembly.

7. Check dimension elevation, matching and then clear for full weld.

8. Weld as per relevant Standards

9. Dye tests the root run.

10. Flush grind final run, align, tighten, H.D. Bolts and Turn buckles lock, erect drain box

assembly & connect DT drain pipe & weld.

11. Hand over for concreting.

Erection of Draft Tube Cone :

01. Lower two bottom cone segments, align with DT liner and Tack weld.

02. Lower two top segments of cone and align.

03. Check elevation of DT cone as per drg. Correct if necessary.

04. Check alignment of cone w.r.t. X & Y axis within 2 mm. Top center of D.T. cone to be in line

with D.T. liner center within ± 2 mm.

05. Measure the inner diameter of cone at the top. If it is not as per drg. correct it.

06. If all readings are ok, then tack weld all turn-buckles.

07. Weld the joints as per relevant standards and dye test the root run.

08. Release for concreting up to casing of piers for spiral casing and stay ring.

SL.NO DESCRIPTION PAGE NO

Erection of Foundation Parts

1. STAY RING 29

2. SPIRAL CASING 30

3. RUNNER ENVELOP 31

4. PIT LINER 32

STAY RING

(A) PRE ERECTION CHECKS

(i) Check for availability of all the items as per drawing.

(ii) Check for any damage during transportation & repair if necessary.

(iii) Check all the pier details as per drawing.

(iv) Check & prove threads on joint bolts & nuts.

(v) Establish center line (x, y Axis) & Datum elevation given by the civil wing.

(vi) Check welds preparations for site welding joints as per drawing.

(B) ERECTION

(i) Transport of stay ring.

(ii) Assemble in service bay and heat and tighten the Joint bolts to achieve elongation as per

drawing.

(iii) Use the sling given as per drawing and lift.

(iv) Lower the Stay ring on stools, so that stay ring pedestal are resting on the stool. Align

center & level with respect to station, Center Line, using hydraulic Jacks/Mechanical

Jacking screws.

(v) Ensure Tightness of joints 0.05mm feeler gauge should not go.

(vi) No step at joints on top & bottom machined surfaced after joining. Check radius at top &

bottom machined bores.

(vii) Check locking of Joint bolts & Nuts.

(viii) Seal welding of Joints to be done as per drawing requirement. Conduct NDT tests as per

drawing requirement.

SPIRAL CASING

(A) PRE-ERECTION CHECKS.

(i) Check for availability of all the items as per drawing.

(ii) Check for any damage during transportation & repairs if necessary.

(iii) Check and prove threads on holding down, bolts & jacking bolts & other hardware.

(iv) Check weld preparation for site welding joint as per drawing.

(B) ERECTION

(i) Assemble the spiral segments as per drawing & ensure that gap at joints in axial or

radial direction is 2 to 5m.m

(ii) Match the spiral members with top & bottom contour of stay ring & center line

marked on spiral member with reference to center line of stay ring (± 2mm).

(iii) Weld the spiral segments as per technical requirements given in the drawing.

(iv) Dye check the weld seams for any surface defects in the plate.

(v) Back gouge, grind & dye check for seal run, complete the sealing run.

(vi) Radiograph and ultrasonic Test for all butt Joints to be carried out as per drawing

requirement.

(vii) Lower the test cylinder and fix it in position.

(viii) Place test cone and weld with spiral inlet.

(ix) Carry out the Hydraulic testing of spiral casing at pre test pressure and time as

given in drawing.

(x) After successful completion of Hyd. Test, remove test cone & test cylinder.

(xi) Complete the installation of holding down bolts, anchors, wedges, & lock all the

hardware.

(xii) Check the leveling & stay ring.

(xiii) Carry out erection, welding and NDT of inlet pipe as per drawing.

(xiv) Recheck the alignment leveling of stay ring before handing over for concreting

Runner Envelopes

A. Pre Erection Checks.

1. Trial Assemble two halves at service Bay.

2. Check diameter.

B. Erection.

i. Runner Envelope to be lowered, after lowering for Ist out before stay ring.

ii. Centering w . r . t . axis of stay ring and check diameter.

iii. Fastening, anchoring and welding with stay ring.

iv. Welding of make up piece with D. T. cone & Runner envelope.

v. Dye testing of seal welding of joint flange to be done.

vi. Spider assembly to be carried out before concreting, as per requirement of drawing.

vii. Recheck: the centering of Runner envelope after concreting.

PIT LINER

ERECTION

A. LOWER THE PIT LINER SEGMENTS

1. The mechanical surfaces for fixing the servo motors are equidistant from X & Y axis (with

tolerance as per drawing) & are vertical. 1 mm. per meter

2. Top dia of pit liner (± 5 mm)

3. Welding to requirements as per drawing.

4. Welding of anchor plates.

5. Installation of pipes / Pipes sleeves for routing of air, water and other pipe lines. Also check

that embedded pipe carrying in this state of concreting are installed and the free ends are

blanked off by welding metal plate. Ensure placement of sufficient sleeves for routing cables

etc also.

SL. NO DESCRIPTION PAGE NO.

1. Runner assembly in Erection Bay, testing &

Testing of Cone assembly

2. Pivot ring assembly

3. Outer Top Cover assembly

4. Trial assembly of G.V with outer

Top Cover & dismantling

5. Guide Apparatus Assembly

6. Runner & shaft assembly with outer top cover

7. Lowering of runner assembly with

inner top cover &final assembly & centering

8. Installation of Regulating Ring

9. Installation. of G V. servomotor

10. Guide Bearing

11. Shaft seal

12. Oil-Header

13. Governing Equipment

14. Installation of Metering Instruments

RUNNER ASSEMBLY

1. Check availability of all materials as per drawings.

2. Perform visual inspection for any damages, report to unit if any abnormality is noticed.

3. Check the match markings during dismantling (if the runner is received at site in assembled

condition).

4. Perform overhauling internal checking of runner as per drawings.

5. During reassembly of runner as per drawing, check the following:

a) Ensure usage of proper / suitable settings for lifting & twining of runner.

b) Check the machined surfaces of piston, servo motor cylinder, sliding blocks and other

components against any scratch, dents etc.

c) Check that the rubber items such as 'O' seals, sealing, cup scales etc are in good condition.

d) Check that the threaded holes and fasteners are not damaged.

e) Check the grooves and rubber cords for their sizes.

f) Check correct joining and assembly of rubber cords and other seals.

g) Check the free movement of sliding blocks.

h) Check that the locking of Bronze Bushes are as per drawing.

i) Check that the pre stressing of fasteners is done as per drawing reference.

j) Check that the locking on laterships, washers, plugs and valves are as per technical

requirements/details of drawing.

k) Assemble runner shaft and servo tube with runner as per drawing

l) Elongate coupling bolts as per the values mentioned in the drg.

m) Measure and record the clearance between runner hubs & blade, it should be as per

drawing value.

n) Perform testing of the Runner as per test procedure technical data provided in the drawings

supplied by manufacturing unit.

Drawing to be referred

1. Tools tackless for runner shaft

2. Runner assembly

3. Shaft arrangement

4. Arrangement of all tubes of runner servomotor

5. Testing devices for runner & shaft

RUNNER ASSEMBLY

Overhauling, Shaft assembly, Hyd. Testing

A. RUNNER

1. Runner of a Francis turbine is dispatched to site, fully assembled or partly assembled and

partly loose depending on its overall size / transport limitations. Partly assembled runner

comprise of hub, turning mechanism, piston, runner blades, bottom cover etc. The loose

components may be runner servo tubes, piston rod, cone and other hardware.

2. Check all the materials as per drg & all tools available for carry out overhauling.

3. Carry out dismantling, overhauling of partly assembled components, hydraulic testing of

completely assembled runner at site in accordance with technical requirements, to ensure

trouble free operation.

4. Carry out trial lowering of assembled runner in to the runner chamber if called up before its

assembly with shaft to check and ensure clearances between runner blades and runner

chamber with runner blades pulled out. In the event of clearances being less than those

specified in the drawing, correction is done either by grinding the tip of runner blades / runner

chamber in the complete zone of runner blades operation (i.e. close to open & open to close).

B. OVERHAULING ASSEMBLY

1. Runner received in site in dismantled condition, runner blade received at site separately.

2. Place runner on pedestal.

3. Remove bottom cone & perform through checking inside. While remaining bottom cone ensure

match mark is there.

4. Assemble any loose components & carry out tightening of fastener, locking called in drg.

5. Fix bottom cone as per match mark & perform tightening & locking.

6. Turn the portion of the runner & lower it over the platform made for runner blade fixing.

7. Carry out assembly of runner blade with cup seals as per instruction given in drg.

C. ASSEMBLY OF TURBINE SHAFT WITH RUNNER

1. Place the runner leveled on stools / wooden sleepers.

2. Check the mating surface of turbine shaft & runner for trueness.

3. Check & ensure the holes of coupling bolts in runner & shaft and coupling bolts are as per drg.

4. Prepare shaft in line with general guidelines and check trueness of all machined surfaces.

5. Check and prove bedding of guide bearing pads with guide bearing journal of shaft, with shaft

in horizontal position (Ref. Instructions for bedding of pads) before runner shaft assy start.

6. Carry out cleaning, acid pickling, neutralization and oil rinsing interiors of oil servo tubes. Insert

the lower part of servo tube in shaft bore before runner shaft assy start.

7. Turn the shaft to make it vertical along with servo tube (runner servo tube is suspended with

chain pulley blocked to the same crane hook connected to shaft).

8. Transfer and lower the shaft on to runner. Maintaining accessibility with shaft suspended, lower

and assemble servo tube with piston rod coinciding match marks and using dowels. Carry

out locking of fasteners and dowels as called for.

9. Install O-seal, lower the shaft and carry out assembly of shaft with runner, coinciding the match

marks. Install all coupling bolts, tighten to required stress / elongation as per technical

requirement & lock the nut.

10. Check soundness of runner shaft assembly joint with the help of 0.03 feeler gauge. In the event

of correct assembly, feeler gauge will not pass.

11. Cover the open end of servo tube temporarily to avoid entry of foreign materials in to the

system.

12. Prepare FQA log sheet for elongation tightening & completion of runner shaft assy.

D. HYDRAULIC TESTING OF RUNNER & CHECKING LEAKAGES

1. If possible, Install PP set, pressure vessel, HP compressors and commission them /

alternately install these equipment’s provisionally for testing of runner.

2. Carry out laying and connection of pipes as per the scheme of testing supplied by the

manufacturer.

3. Carry out testing of runner in the manner stipulated in drawing and check leakages through

sliding mechanisms.

Note : Oil leakage is not permitted, through the cup seals of runner blades.

4. Testing be continued for the duration as indicated in drawing.

5. After successful testing, carry out locking of all fasteners as called in drawing.

Note : Oil leakage is not permitted, through the cup seals of runner blades.

E. INSTALLATION OF RUNNER SHAFT ASSEMBLY

1) Runner shaft assembly is lowered along with turbine top cover. Runner shaft assembly is

supported on top cover with a suitable supporting bracket fitted at the seat of turbine guide

bearing. Turbine guide bearing skirt rests over this bracket.

2) Lower the complete assembly in to runner chamber and carry out assembly of top cover using

seals dowels and fasteners etc. Lower runner shaft assembly further to make GB skirt rest

over the bracket.

3) Carry out leveling at turbine shaft flange and centering of runner with runner chamber.

PIVOT RING INSTALLATION

1) Check for the availability of all the materials as per drawing.

2) Perform visual inspection for any damages. Report to manufacturing unit if any abnormality is

noticed.

3) Check the matching surfaces of pivot ring for any burr / foreign materials. Clean, if any.

4) Ensure availability of proper tools slings etc. for erection of pivot ring.

5) Check the runner envelop flange level. Grinding to be done if required to achieve the level.

6) Lift the pivot ring individual segments and lower them on wooden pegs kept on the runner

envelop / stay ring, for their assembly.

7) Lift the assembled pivot ring, and lower them over the cleaned resieng surface.

8) Tighten the holding down bolts.

9) Align & level pivot ring as per instructions given in drawing.

10) Lock the bolts as per drawing requirements.

ASSEMBLY OF OUTER TOP COVER

Outer top cover is in 4 segments. The segments are to be lowered in pit as individual segments.

1. Clean joint flanges and check for smoothness.

2. Assemble all four segments of outer top cover inside turbine pit.

3. Sling the assembly and lower on speed ring flange as per match mark & support / hang

suitably.

4. Match holes of speed ring flange with that of outer top cover.

5. Put H.D. bolts and tighten.

6. Lock the bolts as per drawing requirement.

Trial assembly to be done by lowering guide vanes using lifting tackles. During lowering of G.V.

the outer top cover may be lifted as per drawing and position Guide vane assembly. The

procedure of Trial assembly is given in following pages. During final assembly of guide vane

also, the G.V.S. are lowered after lifting Top cover in site using hooks provided in barrel. Final

assembly procedure is also given in following pages.

Check availability as per drg.

Perform visual inspection report

Ensure availability of T & Ps.

Check the leveling of speed ring top flanges and groove area. Grind them if necessary to

achieve drg. Value.

ERECTION OF GUIDE APPRATUS

PRE-ERECTION CHECKS

1) Generator barrel is cleared of all civil materials and chipping of stator, lower bracket

foundations completed.

2) Generator barrel is painted except stator, lower bracket, and upper bracket foundations.

3) Turbine pit is cleaned of all civil materials and is painted.

4) All flanges and threaded holes of stay-ring are cleaned and surfaces deburred.

5) Horizontality of stay-ring flanges checked and corrective action executed wherever required.

6) All components of guide apparatus and erection devices as per drawing are received.

TRIAL ASSEMBLY OF GUIDE APPARATUS

1) Even through the guide apparatus assembly is proved in the manufacturer’s unit, trial

clearances and free turning movements of guide vanes are as per technical requirements

and to establish, lower ring, top cover positioning and dowelling.

2) Remove preservatives and clean all the components of guide apparatus and prepare the

components for assembly as per general guidelines.

3) Depending on type of design, lower ring may be assembled finally with seals.

4) Assemble lower ring-using dowels to coincide with XY match marks of stay-ring.

5) Centre the pivot ring bent runner envelop

6) Install all holding down bolts of lower ring and complete tightening.

7) Lower and position guide vanes as per number match marks.

Note : Thin layer of grease is applied on bearing and guide vane lower stem before

installation.

8) Assemble four upper guide vane bush housings, 90 degree apart on top cover. Lift the top

cover precisely leveled with the help of turn buckles and crane and lower it on stay-ring.

9) Position the top cover using dowels and reference match marks.

10) Install alternate holding down studs of top cover and install all upper guide vane bush

housing (thin layer of grease on guide vane journals and bush housing before installation).

11) Check and ensure free turning of all guide vanes. While tightening the nuts of holding down

studs till tightening of all nuts of top cover is finally completed.

12) Bring all guide vanes to close position, to check and ensure the clearances of guide vanes

with top cover at leading and trailing edges are as per drawing requirements. In case of

deviation from the drawing requirements, corrective action is taken wherever required.

13) Carry out bedding of guide vanes and correction if need be.

14) Lower inner top cover & align it.

15) Complete reaming, doweling of lower ring and inner top cover & outer top cover.

FINAL ASSEMBLY OF GUIDE APPARATUS

PRE-ASSEMBLY CHECK

1) Dismantle and remove all the components assembled for trial assembly.

2) Check the rubber cup seals and O-seals do not carry any cracks and are not de-shaped.

3) Install cup seals and retaining rings on lower bush bearing of guide vane and ensure that

retaining ring does not interfere with lower collar of the guide vane. In case of interference,

the retaining ring shall be suitably machined.

4) Lower guide vane in position.

5) Install rubber seal of top cover on stay-ring & complete the assembly of top cover with stay ring

using dowers pins & fasteners ( to ensure proper assembly of top cover stay ring ,check gap

between top cover & stay ring flange by 0.03 mm feeler gauge ,which should not pass).

6) Assemble guide vane bush houses with seals and check free turning movement of each guide

vane. (ensure bush house installation with reference to grease port for pipe connection)

7) Guide vane should move freely when turned by one person by using spiral spanner supplied as

erection device by the manufacturer. After installation of bush.

8) Lower runner assembly with inner top cover runner shaft assembly.

Note : Allowable tolerance in centering 0.1 mm Leveling with 0.03 mm/met.

9) To facilitate alignment of generator, the runner shaft assembly is installed in a lower position

from designed level by an amount 3-4 mm more than the spigot height of the generator shaft

flange.

10) Check and ensure centering of runner w.r.t. Lower labyrinth on lower ring is within the specified

limits.

11) Install regulating ring and servo motors (refer instructions for installation of servo motors of

different variants, described separately).

12) Install link mechanism and adjust guide vane end clearances, bedding clearance and

clearance between lever and lever stopper / collar.

13) Check free turning movement of all guides vanes from full close to full open position.

14) Position regulating ring to close of guides apparatus complete centering and provisional

locking.

15) Install connecting rods of servomotors with regulating ring and carry out pre-stressing of guide

apparatus mechanism (refer instructions described separately).

Note : After final assembly of guide apparatus, grease and lubricate all bearings and check

for easy turning movement of guide apparatus mechanism by applying oil under pressure in

the servo motors. The complete mechanism should turn freely at oil pressure not more than 5

kg/sq. cm or as indicated in drawing. In case guide apparatus fails to turn at this pressure, its

causes must be investigated and removed.

16) Prepare FQA log-sheet for completion of guide apparatus assembly in accordance with field

quality checks.

PRE STRESSING OF GUIDE APPARATUS MECHANISM

1. Tightness in guide vanes is determined in the following manner upon the readiness of oil

pressure system, governor and completion of working mechanism in all respects.

2. In closed position of guide vanes, bring the piston of servomotor with stopper, forward by 15

mm by adjusting the length of connecting rod with turnbuckle. While doing this, check that

regulating ring is not disturbed and remains in the closed position of guide apparatus.

3. Take the piston of servomotors without stopper, back by same amount i.e. 15 mm in the

similar way.

4. Tighten lock nuts of turn buckles of both the connecting rods.

5. Apply oil pressure, according to drawing instructions on servo motor piston for closing and

measure the amount of movement of piston. Movement of piston so measured is the tightness

required in the guide vanes.

6. Release the oil pressure and install the piston of both the servomotors from the end support at

a distance of tightness value measured. Complete locking of turn buckles with lock nuts.

7. Apply pressure for closing of guide apparatus and check that.

7.1 The stopper of servomotor moves freely in and out.

7.2 Clearance between adjacent guide vanes all along their height is 00,

when measured with 0.03 mm feeler gauge.

7.3 Guide apparatus servomotor opens to its full stroke, when the oil

pressure is applied for opening of guide apparatus.

8. KINEMATICS OF GUIDE APPARATUS

8.1 Upon completing governor adjustment and readiness of starting the machine check

relationship of guide vanes v/s servomotor and governor, for opening and closing is as

per design requirement (for Francis turbine)

Check relationship of guide vanes v/s servomotor. Governor and guide vanes v/s runner

blade, governor for closing is as per design requirement (for Francis turbine).

8.2 Plot the graph from the values obtained check that the curve nearly matches with the

design values.

INSTALLATION OF GUIDE VANE SERVO MOTORS

A) Pre-erection checks including overhauling and re-assembly

In case servomotors are not put into service within 12 months from the date of its dispatch, the

same may be over hauled. For this following procedure may be adopted.

1) Dismantle the servomotor after proper match marking of all components / joints.

2) Check the cup seal “O” rings of servomotors for any cracks or damage. Check the

interference of cup seals I. D. with sleeve.

3) Clean thoroughly all parts and inside surface of piston and cylinder with solvents like

diesel / petrol check the surfaces of piston, cylinder, piston rings, bushes etc. for any

scratches.

4) Use new cup seals and prepare “O” ring if assembled ones are worn out and if replacement

is necessary.

5) Assemble the covers using “O” ring. Fasten the covers by tightening the studs and nuts.

6) Insert the piston assembly in the cylinder in vertical position, taking care to keep the slot

portion of piston towards oil ports. Lubricate cylinder surface profusely with turbine oil as

soon as piston rings have entered the cylinder remove clamp, used for pressing the piston

rings.

7) Assemble the cylinder cover using cup seals. Fasten the cover with stud nut. Locking of

nuts to be carried out only after satisfactory hydraulic testing, & after checking the opening

and closing of servomotor and checking the seals are intact.

B) INSTALLATION

1. Check and clean the base plates mounted on pit liner. Check vertically.

2. Push / pull the servomotor piston fully in/out. Lower servomotor stopper in position to lock

the movement of piston.

3. Lower both the servomotors in their respective position. Couple mounting plates with

servomotors using studs & nuts.

4. Align both the servomotors to drg. Dimension. Keep the piston rods of both servomotors in

fully closed position (i.e. piston touching the respective cylinders ends).

5. Check the threads of piston rod. If necessary clean and dress with triangular smooth file.

6. Level the servomotor precisely (horizontal) check level by precision block level (accuracy 1

Div = 0.02 mm/m) on piston sleeve level should be achieved with 1 division.

7. Assemble the piston rod and connected rod initially, keep 25 mm gap between piston rod

and connecting rod.

8. The connecting rods of servomotors to be assembled with regulating ring keeping the

guide apparatus fully closed.

9. Maintain the distance 1985 of G.V. servo cylinder (Not of piston rods / connecting rods)

and level the servomotor.

10. Now if the gap between mounting plate and plate of pit liner is less than 3mm weld

mounting plates directly to pit liner without using strip, otherwise they are to be welded

using strip as shown in the drawing no.

11. Check the guide vane bedding its nut as per drg value correct it with both the servomotor

operation.

12. Also check and set if necessary the G. V. servo stroke indicator scale.

TOLERANCE:

1. Center line servomotor is parallel to Y axis and at a distance as specified in the drawing (within

1 mm).

2. Elevation of servomotor w.r.t. regulating ring (within 1 mm).

6.0 GUIDE BEARING.

A) Pre-erection.

i) Thoroughly clean all parts and joint faces of bearing oil sump. Use engineers blue on one

face, tighten the joint faces and check the bedding. If necessary scrap the face. Filler gauge

can be used to find out the gap.

ii) Clean the bearing pads with solvent like petrol and white spirit. Check their bedding with the

bearing journal of the shaft. If necessary Scrapping can be done. Also check the bedding of

Disc. Check that stud has spherical curvature where it is pressing the disc.

iii) Measure resistance of RTD with standard mercury Thermometer on heating as well as on

cooling Cycle. Use suitable oils both during above Calibration.

iv) Check the groove sizes and prepare rubber-sealing Ring.

v) Check the working of oil level indicator in Separate oil container out side.

vi) Apply liquid sealing compound (hold tight at joint faces of the Bearing oil sump. Bottom

ring)

B) Erection (before alignment)

(i) Fix. studs called in guide apparatus drg. Assemble bearing housing with dowel and pins,

bolts nuts washer, O-seal respectively, taking care that no step at any joint.

(ii) Install the rubber ”o" rings and position the bearing housing matching with unit axis marked

on the top cover and bearing housing.

Center the center piece with respect to turbine shaft journal (with runner at centre) Tighten nuts

and washer.

(iii) Assemble the pipe assembly in their respective position. Suitably blank it for testing with

kerosene for any leakage through “O” rings. Remove the kerosene after testing.

(iv) Fix studs with holdtite. Assemble the two halves of bearing housing, Match with axis and

complete the assembly of bearing housing. Bearing housing should be checked for any

leakage.

(v) Cover/protect the bearing from dust/foreign material till alignment is complete.

C. DIRECTION (AFTER ALIGNMENT)

Note: After the unit axis alignment is completed, runner centered with respect to runner

envelop and rotating parts are lying vertical and locked. Final boxing up of turbine bearing

can be taken up.

1. Clean the inside area thoroughly with compressed air/Vacuum cleaner and moping cloth.

2. Lower the bearing pads and stud and nut in their respective position (i.e. with respect to RTD &

MST connections). Apply molysuff or any other anti thread seizing grease on the thread of

stud. Insert disc and bring stud near to disc to avoid falling.

3. Install 2 Nos. dial indicators at 90° apart to measure/check the shaft movement. Set these dial

indicators to zero value. Press all the pads so as to touch the shaft journal.

4. With all bearing pads touching shaft, set the gap of 0.15 to 0.2 between the disc and stud

(Spherical surface) and lock the nut. Re-check the above clearance.

5. Mount RTD and MST (already calibrated outside).

6. Install bearing cover with all other items as per drawing with "O" seal, Gasket etc.

7. Assemble bearing oil level controller with its probe.

8. Record all the readings achieved in log sheet.

9. Fill the turbine oil in bearing and centrifuge the oil till it is clear (APPROX) 1 5 TO 20

circulation’s as a guide line

Tolerance: Centering of Bearing Body w.r.t. Shaft with in 0.2 mm.

TURBINE SHAFT SEALING

1. PRE-ERECTION

1.1 Dismantle components of shaft sealing, clean them thoroughly and check the joint faces for

flatness and absence of damage.

1.2 Assemble housing of isolating seal, place the isolating seal and housing and cut the extra

length of seal. Test the isolating seal by air as per chemical requirements of drawing and

confirm expansion of seal under air pressure.

1.3 Check and grind the top surface of cups, if any projecting over and above the surface of ring

supporting the working seal.

2. ERECTION

2.1 Assemble base plate / housing of isolating seal with top cover along with “O” seal, maintaining

clearances between rotating and stationary parts as called in drawing (use liquid compound /

hold tite at the joints of housing).

2.2 Install and join isolating seal using suitable adhesive such as anabond / elfy.

2.3 Place the cover plate in position and assemble it with housing.

2.4 Install cups and lip-type rubber working seal and join it with suitable adhesive and complete the

assembly of cover plate.

2.5 Install upper working seal, join and assemble cover plate.

Note:

i) Joints of rubber working seal are made taking into account the direction of rotation of the

machine.

ii)Clearance between rotating and stationary parts is maintained by grinding wherever

necessary.

2.6 Carry out drilling, reaming, doweling of turbine shaft sealing frame with top cover.

2.7 Connect cooling and pressure water piping

3. OIL HEADER (REF SKETCH)

3.1 Oil header is intended to supply the oil under pressure from oil pressure unit to runner

servomotor through a set of concentric pipe lines installed in turbine, generator shafts. The

leakage from the runner passes to pressure pumping set through the bore of turbine,

generator shaft and a oil guide / deflector installed on shaft. Oil pressure for opening closing

of runner blades is supplied through main slide valve of runner installed in HMC of governor.

The runner feed back system & the indicator showing the position of runner blades are also

mounted on the oil header. Oil header is assembled with runner shaft logged after alignment

& center of runner.

4. PRE ASSEMBLY

4.1 Check individual component of oil header is prepared to technical instruction.

4.2 Check surface finish of pipe line assembly as per drawing requirement and there is no ovality

on diameter at location where it passes through the oil header bush.

4.3 Place oil header assembly upside down and ensure the movement of pipe line assembly, in the

oil header bush is smooth.

4.4 Check and record the diameters of bush and pipe line assembly. Check oil deflector items

machined surfaces are true and check level and surface finish exciter shaft for trueness

(where oil deflector is assembled).

5. ERECTION OF OIL TUBES & OIL HEADER

Following sequence of activities to be followed for erection of oil tubes and oil header:

5.1 After assembly of runner, shaft and inner top cover in erection bay check horizontality of the

upper flange of oil tube (lower). Upper flange of oil tube (lower) should be parallel to turbine

shaft coupling face.

5.2 Lower the assembly of runner, shaft and inner top cover along with oil tube (lower) in the

turbine pit (preferably after testing of runner on erection bay).

5.3 Insert middle tube inside generator shaft in erection bay and then lower in the pit keeping oil

tube projected by 200 mm approx. below generator shaft to facilitate coupling of tubes.

5.4 After connecting middle tube to lower tube and assembly of generator shaft with turbine shaft,

check the horizontality of flange of middle tube and throw of its spigot.

5.5 Assembly oil tube (upper), check the horizontality of its top flange and throw of spigot.

5.6 Lower and assemble generator tubular shaft with generator shaft, check throw of spigot in

generator tubular shaft and horizontality of top flange.

5.7 Lower the assembly of central pipe and pressure box. After assembly with upper tube, check

throw of central pipe and pressure box.

5.8 The allowable value of throw for point no. 4, 5, 6 and pressure box is preferably 75% of the

diametral clearance at pressure box bearing, and in no case it should exceed the value of

diametral clearance.

5.9 The allowable value of throw for central pipe is preferably 75% of the diametral clearance at

central pipe bearing, and in no case it should exceed the value of diametral clearance.

5.10 If the throw is more than the value mentioned in Para 8 & 9 above, correction to be done in

respective flange face by suitability scraping or using shims taking care of ‘O’ seal grooves.

5.11 Assembly oil bath and oil guide as per drawing, centralize oil bath to get the uniform

labyrinth clearances.

5.12 Lower oil header body carefully in balanced condition taking guide from central pipe in such

a way that there is no radial pressure or bending effect on central pipe. If the spigot

between body and oil bath does not match, loosen the spigot suitably by grinding and

assembly body to oil bath.

5.13 After checking free rotation and stroking of oil tubes, dowelling of oil header body and oil

bath to be carried out.

5.14 In extreme position of runner blade stroke (fully open and fully close), rotate the machine at

very slow speed for checking any fouling between stationary and rotating components.

OIL HEADER AND OIL TUBES

(A) Pre-Erection.

(i) Check that all items are available.

(ii) Clean all the components.

(iii) Prepare all the "0" seals and check for damage/crack, if required replace it.

GUIDE LINES FOR ERECTION OF OIL TUBES AND OIL HEADER OF VERTICAL FRANCIS TURBINES

1. After assembly of Runner, Shaft and Inner top cover in erection bay check horizontality of the

upper flange of oil tube (lower). Upper flange of oil tubs (lower) should be parallel to turbine

shaft coupling face.

2. Lower the assembly of Runner, shaft and Inner top cover along with oil tube (lower) in the

turbine pit (Preferably after testing of Runner on erection bay).

3. Insert Middle tube inside Generator shaft in erection bay and then lower in the pit keeping oil

tube projected by 200mm approx. below generator shaft to facilitate coupling of tubes.

4. After connecting middle tube to lower tube and assembly of generator shaft with Turbine shaft

check the horizontality of top flange of middle tube and throw of its spigot.

5. Assemble oil tube (upper), check the horizontality of its top flange and throw of the spigot.

6. Lower and assemble generator tubular shaft with Generator shaft, check throw of spigot in

generator tubular shaft and horizontality of top flange.

7. Lower the assembly of central pipe and pressure box. After assembly with upper tube, check

throw of central pipe and pressure box. .

8. The allowable value of throw for point no. 4,5,6 and pressure box is preferably 75%. of the

diametral clearance at pressure bob bearing , and in no case it should exceed the value of

diametral clearance.

9. The allowable, value of throw for central pipe is preferably 75%. of the diametral clearance at

central pipe bearing, and in no case it should exceed the value diametral clearances.

10. If the throw is more than the value mentioned in Para 8 & 9 above, correction to be done in

Respective flange face by suitably scraping or using shims taking care of "O” seal grooves.

11. Assemble oil bath and oil guide as per drawing, centralize oil bath to get the uniform labyrinth

clearances.

12. Lower oil header body carefully in balanced condition taking guide from central pipe in such a

way that there is no radial pressure or bending effect on central pipe. If the spigot between

body and oil bath does not match, loosen the spigot suitably by grinding and assemble body

to oil bath. Grinding can be carried out since there are 4 Dowels of 16mm in addition to 16

studs of nuts of M20 for holding the body with oil bath which keep the joint tight even in

running condition job the Machine.

13. After checking free rotation and stroking of oil tubes, dowelling of oil header body and oil bath

to be carried out.

14. In extreme positions of Runner blade stroke (fully open and fully close), rotate the machine at

very slow speed for checking any fouling between stationary and rotating components.

15. CHANGES DUE TO REVISION: NIL

16. ENCLOSURES: Sketch No. HTE/SK/001 & HTE/SK/002

Tolerance: 1. Centering of oil Header - within 0.1 mm

2. Centering of Center tube - within 0.15 (By rotational check).

GOVERNING EQUIPMENT

(i) Pressure pumping set.

(ii) Pressure Receiver.

(iii) Hydro mechanical cabinet & runner control mechanism.

(iv) Feed back mechanism.

Pressure Pumping set

(A) Pre - erection

(i) Check all the pockets of foundation are as per drawing. Ensure sides of these pockets are

slightly rough for proper bondage of concrete.

(ii) Chip the concrete to make it supporting surface level, if necessary.

(iii) Check that all the blanking flanges are intact.

(B) Erection.

(i) Lift the complete P.P. Set assembly on 4 equal wire Ropes, using eye bolts in fairly levelled

condition

(ii) Install the P.P. Set as per drawing dimensions. Check the elevation at 4 places. Ensure no

gap exists between supporting brackets and concrete.

(iii) Check the vertically by plum bob at pipe flanges.

(iv) Fill the pockets by concrete and allow it to cure.

(v) Check that motor is free, bearing is sound. Grease the bearings.

(vi) Do not run the motor with out oil in the tank.

(ii) Pressure Receiver

(A) Pre-Erection .

(i) Check that foundation pockets are as per drawing.

(ii) Remove manhole door and inspect for any rusting from inside surface or foreign material

during Transportation. Check the paint condition from inside.

(iii) Place the manhole door in the position if required replace the gasket.

(B) Erection.

(i) Lift the pressure receiver in balance condition and assemble it on the foundation bolts.

Align the pressure receiver as per drawing dimension. Care to be taken that angular

position of the mountings are as per drawing.

(ii) Check the verticality by pump bob on two planes.

(iii) Mount all the fittings on receiver and prevent them from any damage (Glass parts/pressure

gauges).

(iv) Pressure test the receiver with air and check leakage through any fittings.

Hydro Mechanical Cabinet & Runner Control Mechanism

(A) Pre-erection.

(i) Check all the items for any damage/breakage.

(ii) Clean the component cleanly.

(iii) Check the location and size of the pockets are as per drawing dimension.

(B) Erection.

(i) Install the hydro mechanical and electrical cabinet as per the drawing.

(ii) Use leveling screws to leveling screws to level and achieve elevation as per drawing.

(iii) Check the verticality of the cabinets by plum bob and also check level, with precision level,

of the rod for free movement of kinematics.

Note :-

After installation of above panels dust/ moisture in this area should not be allowed. As such, all

precautions like chipping/cleaning in the surrounding are to be taken prior to installation of these

cabinets.

Arrangement of PP set - 02210114201

Arrangement of pr. Receiver - 02200114201

Hydro mechanical cabinet - 02085014101

Runner control mechanism - 02083614101

Installation of feed back System

(i) Check that all items are available and are in sound condition.

(ii) Wire rope be pre-stressed to 300 kg. . Force, for 24 hrs. before installation or as called in

drg.

(iii) Wire rope joint to be made as suggested in technical requirement of the drawing.

(iv) Touching of wire rope with any bracket, tube etc. is not allowed. Movement of wire rope

should be free.

(v) All bearings be lubricated and wire rope greased before use.

(vi) Kinks and broken stands in wire rope greased before use.

(vii) Wire rope after installation should be in tension (not loose, to avoid any back lash)

(viii) Sharp bends of wire rope to be avoided.

METERING AND INSTRUMENTS AND SHEAR PIN CONTACTS

A) METERING INSTRUMENTS

i) Calibrate pr. Gauge, DTTT’s, RTDs, etc. called in drg.

ii) Install metering instrument panel and assemble all instruments as per layout drawing.

Carryout laying, welding of pipes and install supports, clamping etc.

iii) Dismantle pipes, complete cleaning by blowing air at 5-7 Kg atm.

iv) Install all pipes and clamping arrangements with supports.

v) Install pressure gauges on draft tube cone, penstock, spiral case and other instruments

as per layout drawing.

Note :

1. Carry out hydraulic testing of pipelines wherever called for.

2. Ensure calibration of all metering instruments prior to putting them in service.

B) SHEAR PIN CONTACTS

i) Shear pin is a weak link between strap and guide vane lever and fails in the event of

blocking or jamming of guide vanes. With the failure of shear pin guide vane becomes

free of its turning movement and strap alone moves and opens the contacts of the limit

switch to initiate a warning signal of shear pin failure at UCB. The limit switches are

connected in series with normally closed contact.

C) ERECTION

i) Install all base plates of unit switches, strikers and clamps as per layout details.

ii) Assemble limit switches and strikers with their respective base plates such that the limit

switch remains pressed with striker and the contacts are closed.

iii) Carryout laying, clamping and connecting of cables with guide apparatus open,

providing a little additional allowances in the cable for flexibility.

iv) Complete sealing of glands to ensure water tightness.

Installation of metering instruments – 12100314201

Guide apparatus

METERING AND INSTRUMENT PANEL

1. Calibrate the Pressure Gauge.

2. Calibrate DTT'S and RTDS

3. Mount the Pr. Gauges, DTT'S and RTDS as per the scheme.

4. Check and connect the pipe lines as per the technical requirement given in the drawing and

document supplied separately by SUPPLIER Bhopal.

5. Wiring of the equipment to be done as per the scheme.

6. Calibration of ammeter, Voltmeter, Wattmeter to be done.

AUXILIARIES

01 Cooling water system

02 Compressed air system

03 Drainage & Dewatering system

04 Pipes in Turbine Pit

05 Turbine gauge panel piping

06 Turbine pit platform

07 Monorail in Turbines Pit

08 Arrangement of top Cover Drain pipes

09 Turbine rating Plates

TRANSFORMERSRECEIPT OF TRANSFORMER AT SITE To ensure that a Transformer will function satisfactorily it is important that handling, lifting, storing and assembling are carried out with great care and cleanliness by experienced personnel who are

thorough with various working operations.

This section gives instructions how handling, lifting, storing and assembling should be carried out. For large Transformers it is recommended that the work is done by TARIL or is under supervision by experts from TARIL.

INSPECTION In connection with receiving and unloading at site, and at the final storing place before assembling, the transformers shall be inspected carefully for external visible damages as dents, paint damages etc. After the arrival of the material at receiving points, the customer should, in case of possible damage/loss of any component, make the necessary claims with the contractor’s representatives under intimation to supplier so that such claims can be registered with the transport agents. Before unloading, the condition of packing and of the visible parts should be checked and possible traces of leaks verified (condenser bushings). If necessary, appropriate statements and claims should be made. Drums containing oil which have been dispatched separately should be examined carefully for leaks or any sign of tampering. All drums are dispatched filled up to their capacity and any shortage should be reported. As a principle we never supply partly filled drums. In order to protect the active part against moisture, the transformer tank is filled with nitrogen during transport at an over pressure of 0.2kg/cm2 approximately at room temperature. Check immediately the gas pressure at the arrival. A positive pressure indicates that the tank and the transformer components respectively are tight, and that the active part including the insulation materials is dry. If there is no positive gas-pressure, transformer should be immediately filled with dry Nitrogen gas at pressure of 2 PSI without loss of time.

DAMAGE/LOSS Damage or loss of any component should be reported to Supplier immediately. Photographs or other useful evident should be submitted wherever possible. When the transformer is dispatched filled with oil, level in transformer main tank should be checked & if the level is below the indicated level in main tank the same should be reported to the supplier immediately & also the same should be mentioned in LR copy. When the transformer is dispatched filled with oil, a sample of oil should be taken from bottom of the tank and tested to IS: 1866. If the dielectric strength is below 50KV, when tested on standard IS: 1866, the matter should be reported to supplier along with insulation resistance values of the various windings to earth. Drums containing transformer oil which have been dispatched separately should be examined carefully for leaks or any signs of tempering. All drums are dispatched filled up to their capacity and any shortage should be reported to us immediately.

UNLOADING The transformer should be unloaded by means of crane or suitable device of sufficient capacity (Please refer rating plate for weight detail). For lifting purpose lifting lugs are provided on the top cover & on the sides of tank. Lifting lugs on the sided of tank are lifting the complete transformer, whereas the lugs provided on the tank cover should be used only for lifting the cover. Lifting lugs for transformer lifting are painted red. Check at lifting of complete transformer that the lifting wires/ropes are not in contact with bushing or other components on the cover. Four jacking pads are also provided for lifting the transformer with the help of jacks. Bidirectional skids are also provided on the bottom of the transformer, in the form of channels having towing holes on both the sided & also holes for foundation of transformer. Transformer should be jacked up using the projections specially provided for that purpose. Jack should never be placed

under any valves. To avoid undue mechanical stresses the transformers must be kept on reasonably level foundation.

ASSEMBLY OF WHEELS

Whenever wheels are supplied with transformer, movement of transformer at site is carried out by mounting these wheels.

Mounting of wheels under transformer is to be done as per roller arrangement drawing. In power transformer wheels are designed such a way that conservator side wheels are of slight higher in height fin the view of keeping transformer shortly inclined to release trapped air from main tank and to avoid accumulating rain water on the tank top cover. While fixing the rollers, the flange should come on the inner side of the rails. Transformer placement can be with or without rollers as per applicable GA/foundation drawing. When the transformer is in the final position, the wheels shall be locked to prevent accidental movement of the transformer.

STORAGE

After arrival at site, it is desirable to erect and commission the transformer with minimum delay. In case this is not possible the transformer shall be erected at its permanent location with conservator and breather fitted and dry oil filled to the correct level. Whether storage or in use, the dehydrating breather must be fitted on all the transformers which are oil filled. The breather incorporates an oil sealing device which must be filled with oil, to the level marked, to be effective. The condition of silica gel must be checked periodically, particularly during monsoons.

Dismantled equipment and components are packed to be protected against normal handling and transport stresses.

All other accessories should be stored in a covered dry place. It should be ensured that there is no damage to the gasketted joints and that all the blanked joints are tight.

Goods stored outdoors must not be placed directly on the ground, and should be covered carefully with tarpaulin or similar material.

The tap changer, if provided, should be operated at 6 monthly intervals. Two of three runs from one end of the range to the other and back are sufficient.

Heaters on Marshalling kiosks, etc. should be kept energized. If for this purpose, power supply at the appropriate voltage to suit the heater is not available, temporary heaters should then be installed to suit the site voltage. The provision of heaters is important and failure to provide them may result in extensive damage to the contents of the kiosk because of condensation.

If oil received in drums is not likely to be used immediately the drums should be stored in a covered space where the temperature variation is minimum. If it is necessary to store the oil outside, adequate protection must be provided at all times. Oil drums should be stored in horizontal (lying) position with both the bungs also in horizontal position.

INDOOR STORAGE The following items shall be stored indoor.

All the Bushings. Insulating Materials & Paints. M.Box R.T.C.C. & Motor Drive of OLTC. Turrets with C.T. mounting. Components like B. Relay, MOO, PRy, Pressure gauges & Flow Indicators, Breather. Cooling fans & Pumps.

OUT DOOR STORAGE Oil Drums: To be kept Horizontal and over two wooden planks. Care is taken that the caps

shall be at 45 deg. from Vertical Radiators & Conservator. Frames, Pipes & Pipe supports. Rollers, Cable Box.

INSTALLATION

LOCATION AND SITE PREPARATION Transformer should be placed on the foundation so that easy access is available all around

and diagram plates, thermometers, valves, oil gauges, etc. can be easily reached or read. Adequate electrical clearances are also to be provided from various live points of the transformer to earthed parts.

ONAN type transformers depend entirely upon the surrounding air for carrying away the heat generated due to losses. For indoor installation, therefore, the room must be well ventilated so that the heated air can escape readily and be replaced by cool air. Air inlets and outlets should be of sufficient size and number to pass adequate air to cool the transformer. The inlets should be as near the floor as possible and outlets as high as the building will allow. Where necessary, exhaust fans can be installed for the purpose.

The transformers should always be separated from one another and from all walls and partitions to permit free circulation of air. Where walls are provided, it should be ensured that the transformer gets good ventilation as mentioned above for indoor transformers. Provision should be made for the emergency drainage of the oil from the transformers

(e.g. in case of fire in neighboring apparatus or bushing or the transformer tank), by surrounding the transformer plinth with sump filled with small pebbles.

ASSEMBLING THE TRANSFORMER By means of the Part list and the Transformer GA Drawing, the assembling of a fully completed transformer is carried out according to the following Instructions. The following precautions are to be taken:

Fire-fighting equipment shall be available near the oil-treatment equipment as well as at work on and adjacent to the transformer.

Transformer oil is inflammable and under certain circumstances in a confined space may become explosive. Naked lights & flame should never be used near a transformer.

Check that there is no overpressure in the transformer when blanking plates or connection lids are to be opened.

Workmen having access to the interior of a transformer should empty their pockets of all loose articles. Any spanners or other tools used should be securely tied with a tape so that they can be recovered, if accidentally dropped.

All loose objects, tools, screws, nuts etc., shall be removed from the transformer cover before opening the connection and blanking lids.

All loose objects (tools, pencils, spectacles etc.,) shall be removed from the boiler-suit pockets etc. Before starting the work through man holes.

Tools to be used inside the transformer/reactor -e.g. for tightening of screw-joints- shall be fastened to the wrist or another fixed point by means of cotton tape or string.

Tools with loose sleeves and tools with catches must not be used at work inside the transformer.

Fibrous cleaning material should not be used as it can deteriorate oil when mixed with it. The presence of loose fibers in suspension in transformer oil can reduce its insulating properties. The presence of loose fibers in suspension in transformer oil can reduce its insulating properties. If any cleaning or wiping is necessary this should be done with clean and dry oil, using soft non-fluffy cloth.

Check healthiness of all the accessories and components dispatched separately with respect to GA Drawing and packing list.

All components dispatched separately should be cleaned inside and outside before being fitted.

A transformer is best protected from damp hazard by circulating warm, dry oil through it

until temperature is 5° C to 10° C above ambient. This should be done before allowing external access to the interior of the tank. The warm oil should be circulated as long as transformer is open to atmosphere,

Oil pump & all joints in the oil pipe work should be airtight to avoid entrance of air through leakage joints.

The active part (core and winding) should be exposed to the surrounding air as short time as possible. Open therefore only one blanking plate or connection lid at a time for remounting of bushings, valves etc.

Check Conditions of Leads, Connections, Tap changer, General conditions of insulation etc.

Check that the bushing leads set without being too close to ground or other points of different potential.

Core-ground; this is checked with the megger after removing earth connection. Before entering into a N2 filled transformer make sure that sufficient Oxygen is available

inside.

GASKETS The sealing system normally used against oil and gas in transformers and belonging components has rubber bonded cork gaskets at joints. Whenever the blanking plates are removed to fix detached parts such as bushing turrets, etc., a new gasket shall be used while fixing the same. A set of new unused gaskets of correct size and thickness is supplied with every transformer for this purpose. Gaskets are best stored in such a way, that they must be protected from damp, oil and grease To make a gasket joint, first clean the metal surfaces ensuring that they are free from oil, rust, scale etc. Using one of the flanges as a template, punch the necessary bolt holes. Insert the bolts and tighten the bolts sequentially,

a little every time so that uniform pressure is exerted on the gasket until the gasket is compressed to about 2/3 of its original thickness. Joints should not be subjected to pressure until tightening is complete. If care is taken in making joints, and in handling the gasket, it is possible to break and remake a joint several times, using the same gasket. Bolts/studs should be tightened lightly and diagonally in the sequence. Do not over tighten, otherwise gasket will get crushed.

OIL FILLING Before filling oil in the tank, it should be tested to meet the requirements as per IS:1866. In case oil does not meet the requirement, it should be processed and shall only be used when meets the requirements. For transformers dispatched gas filled, remove N2 gas from the tank by means of a vacuum pump and take full vacuum and check & rectify if any leakage is there & keep the transformer under vacuum for 12:00 HRS. The filling of oil inside the tank should be done under vacuum & fill the transformer main tank up to top cover. Do not open any blank flange for erection without filling oil up to top cover. Transformer of high voltage rating (66KV and above) have their tanks designed to withstand full vacuum. Below 66KV class transformer, full or partial vacuum should not be applied without consulting manufacturer. When filling a transformer with oil it is preferable that the oil be pumped into the bottom of the tank through filtration machine. It should also be ensured that the tap changer board, relief vent diaphragm, conservator, etc. are not subjected to full vacuum as these may not designed for the same. In case the transformer is provided with OLTC of in-tank type, while evacuating the main transformer tank, the diverter switch compartment must also be evacuated simultaneously so that no undue pressure is allowed on the Tap Changer Chamber. While releasing vacuum, the Tap Changer vacuum should also be released simultaneously. For this, one equalizer pipe should be connected between main tank and tap changer.

DRYING OF TRANSFORMER USING FILTER MACHINE Before the drying out is started all fittings coolers and associated accessories shall be fitted. Drying out process of transformer is requiring care and good judgment. If the drying out process is carelessly or improperly performed, great damage may result to the transformer insulation through overheating etc. Transformer should not be left unattended during any part of drying out period. Transformer should be carefully watched throughout the dry out process and also observations shall be carefully recorded. The most practical method of drying out is by circulation of hot oil through a high vacuum filter machine incorporating oil heater and vacuum chamber. The vacuum pump of the filter machine should have capacity of creating vacuum as high as possible but not less than 710 mm of mercury. Where possible, a vacuum pump can be connected to the tank top cover to keep the oil in tank under vacuum consistent with tank suitability. This may speed up the drying out process. Oil should be filled in tank under vacuum.

Coolers and Tap Changers are filled with clean dry oil. Oil samples are taken out from them and tested. Further circulation of oil is carried out till the oil results are satisfactory. The oil temperature as measured by the oil temperature indicator should be of the order of 60’C. In no case temperature of oil inside the filter machine should exceeds 70’C. The circulation is continued till insulation resistance and oil samples test are satisfactory. Plot IR values taken at regular intervals against temperature readings. It will be observed that in the beginning IR values drop down as the temperature goes up. The IR values will be low till moisture is coming out of the insulation and start rising before steadying.

EARTHING Tank should be permanently and effectively earthed by means of connection to the earthing terminals provided for the purpose at the bottom of the tank. A good low-resistance earth is essential for adequate protection. The earthing connection should be of sufficient cross-section to carry the LV line current for 30 seconds. Other accessories such as fan motors, oil pump motors, winding neutrals etc. should also be earthed. Earthing terminals are provided on tank for earthing of tank mentioned in General Arrangement Drawing. Ensure that paint on the earthing terminal is removed before connecting the earthing strips. Earth resistance should be measured and it should be within acceptable limit.

COMPLETION OF ERECTION WORK Final topping up is now done up to a level in conservator commensurate with filled oil temperature. Other such as wiring of various alarm/trip contacts, fan motors, pumps motors and other apparatus, earthing of neutral and tank is also to be completed. The interposing valves between the radiators and the tank are opened. The transformer and its equipment are cleaned carefully from dirt, oil, lubricating grease etc. If the paint work has been damaged during transit or erection, touching-up should be carried out with the least delay. The surface to be repainted should be cleaned and free from rust and grease. If rust has begun to form, the surrounding area should also be cleaned thoroughly as rust tends to spread beneath paint work. Failure to maintain the paint work in good condition will result in considerable deterioration of the apparatus during storage or service. After completion of erection work it should be checked thoroughly that there should be not leakage. If any leakage found, it should be immediately arrested.

TOUCH-UP PAINTING A basic principle at touch-up painting should be to restore a damaged paint coat on a surface to the same quality and finish as of the surrounding surface. The touch-up paint should be limited to a surface as small as possible. If the paint work has been damaged during transit or erection, touching-up should be carried out with the least delay. The surface to be repainted should be cleaned and free from rust and grease. If rust has begun to form, the surrounding area should also be cleaned thoroughly as rust tends to spread beneath paint work. Failure to maintain the paint work in good condition will result in considerable deterioration of the apparatus during storage or service. Both damaged and surrounding surface should be cleaned so that all grease, dust and other impurities will be removed. Damages on the primer paint and grinding down to the steel surface should be painted with two coats anticorrosive primer paint.

COMMISSIONING After completion of proper erection, transformer is to be kept ready for commissioning. Before putting transformer in service, following check points and Testing should be done to ensure the healthiness of the transformer.

4.1 GENERAL CHECK POINTS 1. After erection & oil filling, transformer should be checked for any oil leakages from each and every part. If found necessary tighten, replacement of gasket and “o” ring should be done. 2. Valves between Conservator to main tank should be fully open. All radiator valves are also fully opened and locked in proper position. 3. Buchholz relay is to be mounted in position inclined angle of 5 to 7 degree. Ensure arrow mark of relay towards conservator. 4. Air release from all air release plug / screws on Main tank cover, radiators, bushings, buchholz relay, OLTC and Bushing turret to make ensure that no air remains inside the transformer tank. 5. Check the level of oil in main tank and OLTC conservator. Check the MOG operation by depressing the float. 6. Ensure that, all the thermometer pockets are filled with transformer oil. 7. Minimum clearance between live parts to earth should be checked as per drawing. 8. Check the various protective devices (i.e. Buchholz relay, PRV, OSR, OTI, WTI and MOG) should give proper alarm and trip indication. 9. Check the Buchholz relay practically by injecting the air from test cock or by draining the oil from buchholz relay by closing both side valves. Ensure that, buchholz relay floats are not locked and the relay is set at the desired position. 10. Check the color of silica gel in breather is dark blue. Also the oil in oil seal to be filled up to the level indicator. Check the air passage of breather is not blocked. 11. Check weather transformer is earthed properly by two independent earth connections. Paint between earthing terminal and earthing strip should cleaned properly for better connectivity. Also OLTC, Marshalling box, cable box should also earthed properly. Also check for earthing for neutral bushings. 12. Check the incoming voltage and set the OLTC on the corresponding tap position. In case of off circuit tap changer brought to desired position and locked with bolt in plate hole. AVR can also set as per required voltage variation, if applicable. 13. Check terminal clamp on bushings and cable and termination on bus bars. 14. Check functions of the breakers with transformer actual tripping operation. 15. Check oil level in OIP bushing from glass or small MOG (Mounted on bushing). It should be in required level. 16. Check Explosion vent assembly mounting. 17. Check OLTC Explosion diaphragm in healthy condition. 18. Check Transformer painting. Apply touch paint at required places. 19. Check Name plate provided properly. 20. Check Roller wheel stoppers provided. 21. Check Valve between OLTC conservator and OLTC surge relay open. 22. Check BCTs for protection and metering connected to respective circuits properly. 23. Check Bushing thimbles and terminal cops tightness. 24. Check Anchor bolts for roller frames and cooler frame provided.

Gas Insulated Switchgear

Earthing

The earthing system of the GIS is designed according to the IEEE Guide for Safety in AC

Substation Grounding (ANSI/IEEE Std 80-2000).

The earthing system of the GIS is not independent but a part of the substation earthing

system. The substation earthing system includes the earthing grid, which have to provide the

low step voltage in the whole area of the substation, including the buildings as well. For this

reason all metal parts of the substation buildings (mainly the elements of reinforcement) have

to be welded in the crossing points to each other and connected in several places to the

substation earthing grid. Suitable connection points of the earthing grid have to be arranged

close to each outdoor and indoor equipment and metal structure to provide earthing

possibilities.

The earthing system of GIS needs several connections to the substation earthing system.

These indoor connection points shall be placed in the four corners of the GIS room, and in

the cable cellar, below the local control cubicles. (The optimal positions are below the two

endpoints of the LCC line.)

5.1. Interconnections of single phase enclosures

The continuous (equi-potential) enclosures of the single-phase enclosed busbars are

interconnected at both ends. The interconnections are dimensioned to the rated current of

the busbars.

At the outer terminations of the incoming line and transformer bays, next to the triangular

arranged cable sealing end enclosures the three phases are interconnected as well. These

interconnections are dimensioned to the rated current of the bays. The structures are similar,

the cross section are the same as at the busbar ends.

The interconnections ensure the low touch voltage between the enclosures of different phases in the case of short circuit currents as well.

Erection and commissioning

7.1. Site erection of the GIS

The site erection can start if all the civil works are ready, and includes the following jobs:

assembly of the steel support structures mounting of the GIS from shipping units, which were fitted up and tested in the factory

before installation of the local control cubicles secondary cabling between GIS and LCC-s establishing of the earthing system

7.2. Gas handling

The most important component of the GIS is the suitable insulating and arc quenching medium: the

sulphur hexafluoride gas.

As the critical temperature and pressure of SF6 are 45.54 °C and 3.759 MPa respectively, it can be

liquefied by compression and is usually transported as a liquid in cylinders or containers.

The supplied gas shall meet the requirements of IEC 60376 (2005-06) and a certificate of compliance should accompany consignments.

7.3. Tests after erection on site After erection, before putting into service, the gas-insulated

metal-enclosed switchgear shall be tested to check the correct operation and the dielectric

strength.

To reduce the risk of moisture and dust entering enclosures so preventing correct operation of the

switchgear, no obligatory periodic inspections or pressure tests are specified or recommended

when the gas-insulated substation is in service.

7.3.1. Checks and verifications

After erection before the high voltage tests the GIS should have a final inspection. The followings

should be checked step by step:

Conformity of the primary switchgear with the manufacturer's drawings (single line diagram,

gas schematic diagram, layout, section drawings of the different bays)

Conformity of the secondary control and protection circuits with the manufacturer's drawings

(schematic diagrams, connection diagrams, cable plans)

Conformity of the earthing system with the manufacturer's drawings (earthing plans)

Proper function of the direct current (DC) and alternating current (AC) auxiliary supply systems

Proper operation, alarm and position indication of each circuit breaker drive according to the

manufacturer's instructions (operational tests).

Proper operation and position indication of each disconnector and earthing switch drive

according to the manufacturer's instructions (operational tests).

Proper function of the interlocks operated locally from the local control cubicles. (The remote

operation is to be checked together with the central control equipment.)

Proper function of the measuring, protective and regulating equipment including the internal

heating and lighting of drives and cubicles.

Proper condition of each gas insulated flange connection (wholeness, cleanness, tightness of

nuts and bolts, greasing if necessary)

7.3.2. Measurement of gas condition

The gas filling pressure of each gas compartment shall be checked.

The moisture content of the insulating gas shall be checked. The content shall not exceed the

following limits after humidity measurement:

50 ppm (mass) for circuit breaker poles

100 ppm (mass) for other components

7.3.3. Gas tightness tests

Leakage test with gas leak detector has to be performed around the flanges.

7.3.4. Resistance measurement of the main circuit

During the erection the resultant resistance of all bays (in each phase) between the busbar(s) and

the outgoing terminal shall be checked. The resistance shall be calculated from the voltage drop

measured at 300 A direct current (DC) loading current:

The resistance should be compared with the prescribed values and tolerances given by the

manufacturer. The increasing of the resistance usually indicates some problem about the contact

conditions of the tested part. The exact reason should be find and eliminate because it can cause

overheating and failure later, during the work of the GIS.

7.3.5. Checking of the current transformer cores

The ratio and the polarity of each CT core have to be checked. These data have to be

checked by primary current injection. The check has to be made phase-by-phase. The

measuring result shall be recorded in test report.

The current injection circuit can be established during two closed earthing switches

(maintenance or high-speed types), which are placed on both sides of the tested current

transformer. The housing of each earthing switch is insulated from the further part of the

enclosure with a special disc. In normal work this insulating disc is bypassed by a removable

connection. To the tests this connection shall be removed from the first earthing switch, and

the test equipment shall be connected to the connection points on both sides of the insulating

disc. The injected primary test current flows through the closed contact of the first earthing

switch, the current carrying bar between the earthing switches, the closed contact of the

second earthing switch and the enclosure between the earthing switches.

The test shall be made phase by phase and the bypass connection can be removed only at

the place tested. Considering the high current, which is necessary for the test, special

attention has to be made for the mechanical security of the connections, for the proper

contacts, for the placing of the connecting wires and for the proper earthing of the equipment.

After finishing the measurement, before the connecting to the other phase, the bypass

connection has to be replaced onto the earthing switch.

7.3.6. Dielectric tests on auxiliary circuits

After the cabling works of the secondary system are completed, for checking the correct

wiring the voltage test is to be performed with high voltage DC testing equipment. DC voltage

has to be applied between the terminal blocks and the earth point. The neutral point

connection of the tested AC circuit has to be removed during the above mentioned

procedure.

7.3.7. High voltage tests on the main circuits

Since it is exceptionally important for the gas insulated switchgear, the dielectric strength

shall be checked in order to eliminate any causes (wrong fastening, damage during handling,

transportation, storage and erection, presence of foreign bodies, etc.) which might give rise

to an internal fault in the future.

The high voltage site tests are supplementary to the dielectric routine tests with the aim of

checking the dielectric integrity of the completed installation and of detecting irregularities.

Normally the dielectric test shall be made after the switchgear has been fully erected and

gas-filled at the rated density preferably at the end of all site tests, when newly installed.

Such a dielectric test is recommended to be performed also after major dismantling for

maintenance. These tests are to be distinguished from the progressive voltage increase

performed in order to achieve a kind of electrical conditioning of the equipment before

commissioning.

CABLE LAYING WORK

General Instructions:

This section describes general instructions to be observed during cable pulling work.

a) Handling of Cableb) At the time of acceptance and prior to installation, the cable reel should be thoroughly

examined for any outside physical damage or damage to cable end caps. This examination should also include lagging, reel flanges and reel marking, tags and labels. While handling cables, necessary precaution should be taken to prevent damage to the cables.

Correct Handling Cable Drums

Cable reels that are to be transported on trucks must be securely blocked or anchored to prevent rolling. If a reel of cable is to be rolled for any appreciable distance, it shall be rolled in the direction indicated by the arrow on the reel flange or with the outside end of cable trailing, if not marked, so as not to loosen the turns of cable on the reel. When rolling reels on the ground, they shall be carefully eased over any rough surfaces. Care shall be taken to avoid damaging reel lagging in order that outer layer of cable remains protected. In removing lagging from cable reels, care shall be taken not to damage the cable. Remove all nails, staples or bolts from inside flange before unreeling cable. Care is to be taken to prevent cable from dragging.

Before Cable Pulling

1) It shall be confirmed that trench floor or other places where the cable is to be installed are free from any foreign materials such as stones, nails and pieces of concrete, asphalt, brick pieces, glass pieces, sharp-edged objects etc., which may damage the cable. Such materials should be removed at least 30 cm away from the trench. Any water inside the trench should be pumped out completely. The trench wall must be secured appropriately in accordance with specification prescribed by the client. The cable trench curves must be checked thoroughly, to ensure that the minimum bending radius of the cable is attained. Sweet sand (or backfill soil as required by project specifications) shall be evenly distributed on the trench floor with minimum thickness of 150 mm or to a thickness prescribed in the project specifications.

2) Prior to start of cable pulling, Ravin recommends to conduct the DC sheath test on the reel in order to ensure that no damage has taken place during transporting and handling of the cable. Upon completion of the test heat shrinkable end caps, to protect against ingress of water or foreign particles, must immediately seal the exposed area. Whenever a cable is cut, the exposed end shall be sealed to protect from rain, mist or dripping or splashed water by heat shrinkable caps.

The drum should be mounted on transport and laying trailer. For cable pulling, the cable drum shall be set at the opposite direction to the arrow painted on the drum that indicates the direction of rolling during transportation. Care should be taken not to damage the cable by battens when removing them from the cable drum. The direction of pulling should be so chosen so as to require the least pulling strength at the end of the cable path.

3) Reliable communication between the drum, the head of the cable, on curves, entrance to duct, intermediate post and the winch has to be established to effectively coordinate the work process. The equipment to be used should be of proven reliability and should be thoroughly tested before cable installation begins. Ensure that the winch has a pulling recorder and a tension meter, to continuously monitor the cable pulling force. It should not exceed the maximum pulling force of the cable recommended by Ravin.

4) Essential words or signals for cable pulling, at least START and STOP, are fixed and understood by all the associated staffs. The meeting prior to cable pulling is recommended to decide position of watchmen with communicative equipment to guide cable pulling works. Watchmen shall be positioned every 50 metres and at every corner.

5) It shall be confirmed that cable drum, drum brake, winch, rollers, wire rope, drum for wire rope and any other necessary tools/equipment have been set properly. Swivel shall be installed between wire rope and pulling eye to prevent the cable from twisting. At the entrance to the cable trench, a cable guiding and bearer stand is positioned, over which the cable taken off the cable drum is pulled into the trench. The rollers that are inclined towards the centre ensure that the cable is fed centrally into the trench. The rule for curves in the trench is that under no circumstances should they fall below the minimum prescribed bending radius of the cable (15 x ØD of cable). The cable rollers in straight portions shall be set at approximately 2 metre intervals to avoid the slack of the cable pulling. Whereas the cable rollers in bend portions shall be set as close as possible, so as not to be subjected to the sidewall pressures partially. Sufficient numbers of corner cable rollers are positioned on the curves in the trench, to prevent cable sliding off. In field practice anchor pins have proved ideal for anchoring the corner rollers.

6) Final check of trench shall be carried out so as to eliminate the risks that may damage the cable. And it shall be confirmed that trench will not collapse at any portion along the cable route. Timbering/Shuttering shall be provided securely prior to cable pulling at positions where trench may or is liable to collapse.

7) When the cable is pulled into shaft or inclined tunnel, sufficient capacity of brake facilities shall be applied so that the cable may not slip down due to its weight.

During Cable Pulling

1) Maximum pulling speed shall be 7 m/min. The pulling speed shall be reduced at corners, inlets of duct, etc. where the smooth pulling may be blocked. After confirming that no damage has occurred at these portions, the pulling tension may be increased. Necessary action should be taken to eliminate the cause of damages, in case of its occurrence.

2) Watch the cable on the cable rollers, especially at bend portions and maintain sufficient clearance between existing services and the cable along the whole cable route all the time during cable pulling.

3) The pulling tension and the sidewall pressure should never exceed the permissible values. It is essential to be able to control the speed of pulling by monitoring pulling force speed and the length. These parameters should be recorded continuously on a recorder, which is an indication and proof of the correct laying. When pulling force exceeds the maximum permissible setting, the pulling should stop.

4) The outlook of the cable shall be checked and it shall be confirmed that the cable has not been damaged during cable pulling. The cable pulling should be stopped immediately on finding any damage and should not be resumed until the causes are removed. The damage portion of cable shall be repaired as required.

5) When the inner end of the cable on the cable drum is loosened during cable pulling, it shall be tightened again to the cable drum.

After Cable Pulling

1) The outlook of the cable shall be checked whether the cable has been damaged or not. Any damage shall be repaired in a proper manner after careful examination.

2) Integrity of anti-corrosive sheath shall be confirmed by carrying out DC high voltage test on it before and after backfilling. Immediately after the first phase of backfilling and prior to final backfilling, DC sheath test at 10 kV for 1 minute should be conducted to ensure that no damage has occurred to the cable sheath during cable pulling. Upon completion of the test heat shrinkable end caps to protect against ingress of water or any foreign particles, must immediately seal the exposed area.

3) Necessary protection to the cable shall be provided against mechanical damage, vandalism and any other possibility to damage the cable. It is recommended to backfill the trench as soon as possible and not to leave the cable exposed.

4) The cable end shall be raised up higher than the maximum water level expected. The integrity of sealing at the cable ends shall be confirmed to prevent water or any moisture entering the cable. Repair work shall be carried out if necessary.

5) Power cables and auxiliary cables shall be arranged so as to keep the specified distance between them, in order to maintain the current rating capacity and to limit sheath current/sheath induced voltage of the cable and induced voltage on auxiliary cables as per designed values.

HANDLING

Damage to cables can occur due to the incorrect handling to which the drums and cables may be subjected, causing breakdown of the drum flanges and in exceptional cases, movement of the drum barrel takes place. Once this breakdown of the drum occurs, the cable is immediately exposed to damage.

For guidance on handling, please refer to the sketches and notes contained in this booklet, which should be followed closely.

Under no circumstances should a drum be rolled off a vehicle on to a cushion of sand, tarpaulin, etc. This action could crumple the flanges and barrel of the drum, driving splinters and/or nails into the cable.

STORAGEIf any time the drums of cable are required to be stored for reasonably long periods, e.g. prior to shipment or installation, the following points should be noted;

The site for storage of drums should be well drained, hard packed soil, or preferably a concrete surface, which will not allow the drums to sink and so give rise to damage due to the extreme difficulty in moving drums when they are sunk into the ground.

All drums should be stored with the battens intact, and in such a manner as to leave sufficient space between them for air circulation. Check and tighten tie bolts on the drums at regular intervals.

Tier stacking of drums is not recommended. In no circumstances must the drums be stored on the flat, i.e., with flanges horizontal.

All drums, during installation (i.e. when the battens have been removed), should be scotched so that there is no danger of the flanges of drums coming into accidental contact with unprotected cable on other drums. The cables should not be left unprotected.

Cables should be protected from direct rays of the sun by leaving the battens on or covering the cables with thick black polythene sheet.

3. INSTALLATION3.1 Minimum Temperature during installationTo avoid risk of damage during handling, the cable should be installed only when both the cable and ambient temperature are above 0°C and precautions have been taken to maintain the cable above this temperature. However, the cables are suitable for operating at temperatures between below 0°C and the specified maximum limit, provided that they are not bent or struck when at temperatures below 0°C.

3.2 LayingNormally cables are supplied on wooden or steel drums and great care should be taken during running off to ensure that the cable does not kink. The drum position should be chosen so that the longest length of straight trench is at the pulling end, with any severe bends as close as possible to the drum.

It is important that the rolling of the drum to this position should be in accordance with the arrow on the flange – to prevent loose turns from developing during unwinding. The distance of rolling should be kept to a minimum.

Drums should be mounted so that the cable is pulled from the top of the drum, and for very heavy cable, it may benecessary to use a ramp to support the cable during the passage into the trench. As the cable is run off, the drum will rotate in the opposite direction to the arrow on the “ROLL THIS WAY” marking.

The excavated trench should be carefully examined to ensure that there are no sharp edged stones, foundations,reinforcing metalwork, etc. which could damage the cable, and riddled earth or sand should be used as a bedding.

Preparation of the trench, prior to installing the cable, comprises the installation of skid plates, rollers, etc. and paying out the winch rope, if using power assistance. Cable rollers are necessary to prevent the cable from touching the ground, and should be spaced a maximum of 2m apart for normal size cables. Correct positioning of rollers is important to keep friction to a minimum.

The cable should preferably be drawn to its final position in a continuous manner. During stops, the cable will settle between rollers and may cause high strain on men and machines during restarting. Whether the pulling is manual or with a winch, it is necessary for one man to be stationed at the drum with a plank of wood wedged against the flange of the drum so that over-running of the drum is prevented if the pulling stops. Otherwise, many loose turns can easily develop on the drum.

When pulling by a winch it is advantageous for the cable end to be taken by hand as far as possible before attaching the winch rope. This allows the leading cable rollers, skid plates, etc to take the load and settle under well-controlled conditions. The winch operator must, at all times, carefully observe the dynamometer to prevent overloading. On long pulls, good communication is essential, preferably by radio.

When pulling a power winch, more attention has to be given to the maximum pulling load which is permissible. For such installations a pulling eye attached to the conductors is necessary, and for copper conductors a pulling tension of 6 kg force per sq.mm of total conductor area can be applied (with the proviso of 2000 kg force maximum).

Graphite paste should be used for lubrication when cables are being pulled into ducts. For open trench and straight installations, a cable stocking can be used. It is advisable, however, to protect the oversheath with a layer of bitumen tape applied with 50% overlap.

Cables should never be bent to a small radius. As large a radius as space permits should be adopted. Under nocircumstances should the bending radius be less than the minimum permissible limits. It is particularly important to have a generous bending radius when cables are to be pulled by a power winch, so as to keep within the maximum permissible pulling tension and to prevent the cable being flattened around bends or in ducts.

ERECTION OF MEDIUM VOLTAGE (MV) SWITCHGEAR

Before commencing erection of medium voltage (MV) switchgear check that all connections are

tight on busbars and on main and auxiliary circuits. Examine the insulation carefully, because there

have been cases of burned out connections due to failure to observe this precaution.

Obvious faults such as distorted panel work, broken meter glass and damaged packing cases

should be noted and immediate steps taken to rectify the damage or to return the switchgear to

the supplier.

After erection, steps must be taken to prevent deterioration of the switchgear due to damp, dust or

casual damage. Substations should be cleared out and locked fast and should not be used as a site

office, store or workshop after the switchgear has been installed.

When all erection and jointing work is complete the medium voltage switchgear must be inspected

and thoroughly cleaned to remove cuttings of cable, spare nuts, washers, accumulations of dust or

copper filings and tools which may have been left behind.

However, it is dangerous to blow out equipment because dust, filings, light metal scraps, rags and

sawdust can be blown into positions where they become inaccessible and may pass unnoticed.

It is better to clean manually and vacuum the plant.

In the erection of the switchgear the following points should be emphasised.

Where steel channels are used as foundations, ensure that they are correctly laid to an accuracy of

about ±1 mm in 3 m. Use a masking strip to prevent fouling by the floor materials. Read and apply

the manufacturer’s erection instructions and use the correct tools such as torque spanners to obtain

the appropriate tightness of nuts. Make sure switchgear is properly aligned.

This means vertically and horizontally in both longitudinal and lateral directions.

When the floor is being laid and there are no steel inset channels, it should be level both front to

back and should not vary by more than a millimetre or so between cubicle centres. When the floor

is being laid it is common practice to form pockets at the foundation hole positions in order to avoid

having to cut them out of the solid floor at installation time.

The floor should be marked out in accordance with the switchgear assembly drawings usually

provided by the manufacturer to ensure that the switchgear is correctly located with respect to cable

trenches, building walls and other equipment in the room.

A datum line requires to be established usually along the rear foundation bolts, and using normal

geometric methods the switchboard and foundation bolt holes can be located. The method of

positioning the switchgear is dependent on a number of factors such as switchgear size, building

location, site accessibility and lifting tackle available.

Lifting eyes are often either incorporated into switchboards or can be screwed into pre-machined

holes, but generally slinging is necessary and this should be done strictly in accordance with the

manufacturer’s recommendations.

Without the use of cranes, however, the traditional manual methods utilising jacks and roller

bars are effective.

Care must be taken not to exert pressure on weak parts such as control handles during this

manhandling. Positioning of the cubicles should start near to the centre of the switchboard,

installing as early as possible the enclosures associated with any special chambers or trunking.

The first enclosure should be positioned and checked to ensure the side sheets are plumb and that

any runner rails are level in both planes. When the first enclosure panel is correctly set the

remaining enclosures should be positioned successively on alternate sides of this panel to make the

front form an unbroken line.

Adjacent enclosures should be bolted together after they have been correctly aligned using whatever

shimming proves necessary to make sure that the cubicles are vertically and horizontally true. The

fixing bolts should be positioned in the foundation holes and cemented in leaving adequate time for

the cement to set before tightening up.

Checking of cable and other connections

Siemens metal clad switchgear SIMOSEC - Cable connection in cable panel

A further examination of all incoming and outgoing circuit and auxiliary cables, including a test of

the correctness of the connections at the remote ends, should be done; this should include measuring

the insulation resistance and continuity of all cables and wiring including internal and auxiliary

connections.

Where appropriate, phase rotation checks must be made before three-phase drives are energised. All

moving parts must be inspected to ensure they are all operative. Dashpots must be filled to the

correct level with the right grade of fluid, and the operation and accuracy of meters and relays by

secondary or primary injection tests should be checked.

All cable boxes must be properly topped up and compound filling spouts capped off. All insulators

and spouts must be clean and dry and cover plates securely bolted up with all screws in position and

tightened and breather vents clear of obstruction. Ensure that the top of the switchgear is free from

all dirt and rubbish.

A final check on all incoming and outgoing cable connections to terminals ensures that they are

tight and have adequate clearance. High voltage testing can then be carried out to the test figures

laid down in the appropriate BS switchgear specification or as specified by the client’s engineers

who should witness the tests and sign the test results.

After testing, precautions must be taken to discharge any static and remove the test connections

before bolting up any covers removed for testing. Before energising, the operation of all circuit

breakers and relays should be confirmed manually and electrically to ensure that no sticking or

malfunction is present, particular attention being given to manual trip and close operations and to

the operation of overcurrent relays and residual current devices.

ERECTION OF E.O.T. CRANES

GENERAL:

An E.O.T. crane can be divided into different sections as follows:-

(a) Bridge girders, (b) End carriages,(c) Hoisting trolley also known as crab, (d) Long travel machinery,(e) Driver’s cabin/Floor operation.

ERECTION OF CRANE:-

The crane should be erected on an un-occupied floor where no industrial or construction work is to be carried out during erection. The size of the floor must ensure free & convenient handling of the crane during the erection period i.e. setting the crane in erecting position on the floor, turning the suspended crane etc. the most convenient place for erecting the crane is the space between the columns provided there are no horizontal bracings connecting the roof trusses. the roof trusses used for lifting the crane should be checked for stresses during erection with a dynamic factor of 1.2.

Besides testing the rope & trusses for strength, they should be tested for stability under horizontal forces acting at right angle to the truss plane.The winches employed for lifting the crane should be equipped with ratched stops. The wire rope employed for erection must have tags indicating wire breaking forces& should be free of defects, fractures, kinks etc. The minimum safer factor should be three.When hoisting the crane or its parts the following conditions should be kept in mind.

(a) The angle of inclination of the slings should not be less than 45º.(b) To prevent rupture of the rope due to sharp edges of lifted materials, wooden or metal lining

should be used.(c) The number of clamps to be used for fastening the rope should be sufficient.

We should also ensure that the axes of the winch drum should be exactly at right angle to rope direction.

Fig.:- Schematic View of E.O.T. Cranes.

LIFTING THE CRANE:-

Depending on the weight of the crane, the strength of the rope, trusses, the crane can be lifted by one winch or two or four winches. If the weight of the crane is not very high the crane structure can be assembled at the floor & the complete crane can be lifted. in case the crane is very heavy we may lift different portions of the crane in sequence as follows:-

1. End carriages complete with L.T. wheels fitted in position.2. Main girders.3. Hoisting trolley or crab.4. Driver’s cabin & other electrical components.

To simplify the positioning of the different components the crane should be match marked at every joint. Every joint should be bolted only by means of machine bolts.

For the safety of the people engaged in erection work, the following safety rules should be observed:-1. When lifting the crane structure the dangerous zone of assembly must be protected with

flags barriers etc. & no un-authorised person should be admitted in the area.2. Do not lift the crane if the erection area is badly illuminated.3. Although the lifted structures should not be allowed to suspend for a long time but in case of

exception we must see that:-

(a) The safety factors of the ropes & cross girders should be twice than the normal working.

Client: Tato Hydro Power Private Limited, Mumbai

Proposal for EPC execution of Electro-Mechanical Works for 4 x 175 MW Tato – II HEPand the 10 MW Dam Toe Hydropower Plant, Arunachal Pradesh

(Tender Specifications No. CPG/Tato-II/Package-3/EM/3A)

(b) The last line of rope running off the blocked should be clamped near the block.(c) In case the load is lifted by means of hand winch, remove the handles, apply & secure the

brakes.(d) Post workers to ensure security.

4. It is strictly forbidden to stand or walk under the crane when the crane is being lifted.5. The scaffolds must comply with the safety rules. the fitter working on top, must handle the

parts & tools carefully so as to prevent them to fall down.

The erection supervisor must ensure that all the components are assembled in accordance to the sub assembly drawings. after the crane has been fully erected, we must do the electrical connection exactly as per its wiring diagram. Before we actually do the load test we must run all the motions in idle condition. during idle running of different motions we should particularly observe the following:-(a) Eccentric running of moving parts. (b) Alignment of shafts.(c) Fauling of moving components. (d) Any un-usual noise.(e) Presence of lubricant at desired surfaces.

After the idle running of different motions & satisfactory performance of motors, limit switches, brakes & controllers we may go ahead with load testing of the crane in accordance to relevant Indian standards.

If the contract for erection & commissioning of the crane is not given to the manufacturer of the crane, it will be desirable to seek their supervision during Erection & commissioning. This will ascertain the alignments of components & thus longer life of the crane.

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Open Joint Stock Company “Power Machines – ZTL, LMZ, Electrosila, Energomachexport”(OJSC “Power Machines”)