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Power Sector Western Region Technology Day 11 th May 2009

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Page 1: Tech. Day Presentation

Power Sector Western Region

Technology Day

11th May 2009

Page 2: Tech. Day Presentation

Power Sector Western Region

TECHNOLOGICAL TOOLS

Page 3: Tech. Day Presentation

Power Sector Western Region

Use of Electrical Torque wrench for Tightening

Boiler Structure Bolts

At 1 x 500 MW Khaperkheda

Page 4: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 4

Cycle time reduction in tightening boiler structure bolts

Background At boiler erection site thousands of BOLTED JOINTS are to be tightened

MANUALLY using DE Spanners for snug tightening & Torque tightening by trip torque type long handle torque spanner.

The process of bolting arrangement consumes enormous time for achieving desired results, including uniform tightening & ensuring a designed torque value.

This process was identified for taking up Improvement project because of the following

being repetitive in nature

time consuming

labour intensive

having substantial amount of preparatory work to be done before the starting actual process (set up time)

high level of risk involved (some locations for actual work place are above 80 meter above ground level & are to be performed on temporarily erected scaffoldings

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Objective Reduction in time taken for complete bolting arrangement

necessary for a 500 MW Boiler erection (at Khaperkheda site about 40, 000 no. M24 Bolts of lengths 70 – 160 mm are used)

Ensuring designed tightness of bolting arrangement without further need of cross checking by Quality representative

Safer working conditions for Operator

Cycle time reduction in tightening boiler structure bolts

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Evaluation of alternatives

1. Pneumatic torque wrench

Benefits

Available with leading hand tool manufacturers like Bosch, Ingersoll Rand & others.

Widely used in manufacturing plants (automotive assembly lines) where high turnover per day is the hour of need (but here the Operator has a fixed place & jobs move to his operating area one after another).

These wrenches are comparatively lighter.

Drawbacks for us

Difficulties in ensuring dry air to the wrench in all weather conditions

Maintaining desired air pressure at a long distance through a compressor

Requirement of supports since length of air pipes may extend up to 100 meters

Thus making the whole arrangement very clumsy & big.

Cycle time reduction in tightening boiler structure bolts

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Evaluation of alternatives

2. Hydraulic torque wrench

Benefits

Available with leading hand tool manufacturers

Widely used in manufacturing plants

Drawbacks for us

Need sophisticated hydraulic equipment (difficult to maintain)

Require very good quality pressure hoses to feed optimum liquid pressure to the wrench limiting factors

Practically impossible to provide such facilities at sites

Cycle time reduction in tightening boiler structure bolts

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Evaluation of alternatives

3. Electrically operated torque wrench

Benefits

Such wrenches are popular in assembly lines especially where job sizes are bigger & operator has to move around the job

Available with leading hand tool manufacturers

Electrical cables are much smaller, lighter & easily maneuverable

Operate at 1 phase ac supply abundantly available at all areas of sites

Cycle time reduction in tightening boiler structure bolts

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 9

Electrically operated torque wrench (contd..)

Results of Field Trial

M/s Tristar Industrial Tools Pvt limited was a source located for making a demo at Khaperkheda

Trial was successfully done on 10th April 2009 at a height of about 10 meters on Column number 19.

Time taken to fully tighten bolted joint by ETW was about 15 seconds as against 3 to 4 minutes by a handle type Trip Torque Wrench

Substantial saving in operation time for the activity

Saving in manual effort by Operator

Positive assurance of Quality of bolted joint.

Cycle time reduction in tightening boiler structure bolts

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Electric wrench for tightening boiler structure bolts

Technische Daten DEA – Technical data DEA

PLARAD – GERMANY MakePLARAD – GERMANY MakeTechnische Daten DEA – Technical data DEA

Our selectionOur selection Type DEA 12 TLX Torque 200 – 1220 NM Weight 6,8 kgType DEA 12 TLX Torque 200 – 1220 NM Weight 6,8 kg

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Electric wrench tightening of boiler structure bolts

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Electric wrench tightening of boiler structure bolts

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Expected Benefits  

Tangible Saving in Time - On average saving of about 3 minutes per bolt

Saving in manpower cost

No need for Quality representative to ensure desired objective of proper tightness

Additional helper to hold spanner and a trip torque wrench, not required.

Intangible Safety of Operating Personnel (Operators & others assisting him)

from any Accidental fall due to Slipping

Slipping / Falling of the job from temporary scaffolding

Better safety of personnel on ground from falling of long torque wrench etc.

Cycle time reduction in tightening boiler structure bolts

Page 14: Tech. Day Presentation

Power Sector Western Region

Measurement of Face Run- out of IP & LP Rotors by improvised technique at site

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 15

Measurement of Face Run- out of IP & LP Rotors

Normal Practice

Normal practice of measurement of face run-outs of IP & LP Turbine Rotors is

To place them on saddle supports and rotate them (There is only an arc of contact between the saddle and the rotor).

A pin is made and inserted in one of the coupling holes.

A wire rope is wound around the rotor with the pin at one end and the crane hook of the EOT at the other.

Lifting action of the crane hook causes rotation of the rotor.

To aid in rotation of the rotor, copper sheets are placed in between the saddle and the rotor and, grease is smeared to reduce friction during rotation.

Contd…

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Measurement of Face Run- out of IP & LP Rotors

Normal Practice (Contd..)

The normal method has few problems associated with it

1. It is not possible to restrict axial movement of the rotor in order to avoid overshooting the range of the dial gauge.

2. Area of contact being very small, it requires extreme care and control while operating the EOT, lest it should cause an irreparable accident and lead to loss to both men and material.

3. It has often been noticed that there is quite an error between the measurement made at shop and those made at site leading to avoidable loss of time in correspondence, summoning experts from MUs, etc.

4. It gives the feeling of using a very primitive and un-reliable method of measurement.

5. Overall, it is never like measuring the run-outs by anchoring the rotor on a lathe to take the measurements and that’s exactly the cause of the error.

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 17

Measurement of Face Run- out of IP & LP Rotors

Suggested New Method

A simple device is made at site using the following material

Shaft of 40mm Ø x 1000mm long 1 no.

Ball Bearings with Plummer block for above shaft 2 nos.

Supports to anchor the Plummer blocks 2 nos.

Cross arm 1 no.

Dial Gauges for mounting to X-arm 2 nos.

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Measurement of Face Run- out of IP & LP Rotors

Brg with Plummer Block

Cross Arm

Shaft Support provided by UnitExternal Support for anchoring the Plummer Block

Dial Pointers

Dia 40 Shaft

Fixture developed and used

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Measurement of Face Run- out of IP & LP Rotors

Advantages User friendly and costs only Rs.5000/- to make.

Does not require too much of a precision in machining the shaft.

Does away with repeated rotation of the rotor for every reading.

Reduces the risk of the rotor toppling during rotation by EOT crane.

Compares well with the values attained at works on a lathe.

Page 20: Tech. Day Presentation

Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA TrombayTrombay

This was the 1st time the Generator Stator has been lifted by Strand Jack Method in PS-WR. Also, this is the 1st for 250MW Stators in the whole of BHEL. Picture shows Stator lifted off the Blocks.

Page 21: Tech. Day Presentation

Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Trombay….ContdTrombay….Contd

Stator lifting in progress

Page 22: Tech. Day Presentation

Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Trombay….ContdTrombay….Contd

Stator lifted and being moved inside the A-Row of TG Building

Page 23: Tech. Day Presentation

Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Trombay….ContdTrombay….Contd

Stator lifted above the bottom of TG Deck and ready to be moved inside for placement.

Page 24: Tech. Day Presentation

Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Trombay….ContdTrombay….Contd

Picture shows the Strand Jack Hydraulic Control System

Page 25: Tech. Day Presentation

Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Stator lifting by Strand Jack Method at 1x250MW Unit#8 TATA Trombay….ContdTrombay….Contd

Picture shows stator in position

The entire operation was completed in 4 hrs from the start.

Page 26: Tech. Day Presentation

Power Sector Western Region

PORTABLE INDUCTION HEATING MACHINE

Page 27: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 27

INDUCTION HEATING MACHINEConventionally, we at BHEL Power Sector Sites have been using the Induction Heating Machines of EDN Bangalore make. There are certain disadvantages of using this equipment listed below:

1. Too bulky and comes in two parts – one the Induction Heating Equipment proper and the other, the operator’s panel. Weighs a few tonnes.

2. Due to its bulk, moving the machine to different areas of work is an arduous task. Each shift of the machine is a 1 ½ days activity.

3. Often, it has been seen that when the machine is moved from one location to the other is has not been in use for a few months, the next re-start is faced with quite a few problems. The reason is not known.

4. Getting spares on time for the equipment is a big issue. This results in machines with minor repairs and requiring spares quarantined.

5. Overall the machine is not user-friendly

6. Costs around Rs. 75 Lakhs per machine

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Induction Heating Machine -….Contd

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Induction Heating Machine -….Contd Alternatively, there are machines available in the market and being

used by our competitors that is a vast improvement on the EDN Make machine and has the following advantages:

1. Very small and easily portable, thus rendering easy movement of the machines to various locations without loss of vital erection cycle time. Requires only a 2-3 hrs for shifting and re-connecting. The entire machine is as compact as welding transformer and is single modular. Weighs approx. 105Kgs.

2. The connections are very simple and does not need expertise.

3. Though imported, has a presence in the Indian market for the last 3 years and has been used to weld pipes of 94mm thick at Sipat. The machine can be used to thicknesses in excess of 100mm pipes as well. The size of MS Pipe for the proposed 660MW Unit with Full Flow is Φ660 x 102mm.

4. Costs only Rs.30 Lakhs. For every one machine of EDN Make, one can two of this kind.

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 30

Induction Heating Machine -….Contd

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Induction Heating Machine -….Contd

660 MW 800 MW

System Material Size Material Size

MS - Half Flow

P91 OD 508 x 80 P91 ID 370 x 66

MS – Full Flow

P91 OD 660 x 102 P91 ID 480 x 90

HP Bypass – U/S

P91 OD 355.6 x 52 P91 OD 355.6 x 54

HRH – Half Flow

P91 OD 711 x 40 P91 OD 813 x 49

HRH – Full Flow

P91 OD 864x48 P91 OD 1016 x 58

LP Bypass – U/S & D/S

P91 OD 711 x 40 / OD 1219 x10 (SA691 2 ¼ Cr)

P91 OD 864 x 50 / OD 965 x 35

Page 32: Tech. Day Presentation

Power Sector Western Region

Induction Heating for Opening & Tightening Casing fasteners of Steam Turbine

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 33

Induction Heating for opening & tightening Casing of Steam Turbine

Introduction Casing of steam turbines are tightened together by using

threaded fasteners of M48 to M140 size .

These fasteners referred commonly as studs and cap nuts have to be tightened firmly to withstand the high internal pressure and temperature.

During the tightening process, specified value of elongation has to be achieved so that during working at high temperature, the nuts will not slacken .

A recommended practice for tightening these fasteners is heat tightening.

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Induction Heating for opening & tightening Casing of Steam Turbine

Commonly used devices for heating the fasteners

Electric heaters - which include heater elements, cables, power source /transformer of high capacity etc.

Gas heaters. This is relatively simpler method which uses the specially fabricated bolt heating devices - Gas Torches with special nozzles, and oxy-acetylene cylinders , compressed air supply etc.

Main disadvantages of the above two methods

Long time taken for the operation

Due to the slower rate of heating, effectiveness of these methods is less and some other problems such as seizure of the threads also occur quite frequently.

Apart from this, the arrangements required are also complex and time wasted in maintenance / repairs of the equipment in case of defects is quite considerable.

Page 35: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 35

Induction Heating for opening & tightening Casing of Steam Turbine

Induction heating method for threaded fasteners

Induction heating method is being used in other site applications such as preheating of joints for special welding of alloy steel pipe lines in thermal power stations.

This method is very quick and effective means for heating.

By using some modified gadgets, it was found suitable for loosening and tightening of the big size threaded fasteners of steam turbines, valves etc.

SAS Nagpur decided to use the induction heating method for loosening and tightening of threaded fasteners.

This method has resulted in saving valuable time for dismantling and assembly of steam turbines during overhauls. The method is simple and highly effective.

With the use of induction heating method, the problem of seizure of threads necessitating cutting and gouging of the nuts and studs, in LMW design, has been minimized.

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 36

Induction Heating for opening & tightening Casing of Steam Turbine

Comparison of time required for bolt opening

210 MW /500 MW KWU Electric/ Gas Heating Induction Heating

HP inner casing 6 hrs 3 hrs

IP Outer casing 10 hrs 7 hrs

IP inner casing 14 hrs 8 hrs

Time saved for overhauling is 3 days .

For a 210 MW set this translates into a gain of 5.04 million units perday i.e approx. Rs. 2 crore per day

For 500 mw set, 12 million units per day i.e.approx. Rs.4.8 crore perday

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 37

LASER ALIGNMENT KITLASER ALIGNMENT KIT

OBJECTIVETo carry out various alignment works in Turbine erection With high precision. At a reduced cycle time.

WORKS CARRIED OUT Catenary of pedestals Centering of bores of Diaphragms, Pedestals, Shaft Seals etc. Alignment of Rotors.

CATENARY OF PEDESTALS

Accuracy of 10 Microns achievable.Source equipments to be placed at extreme pedestals.Mobile equipment placed in intermediate pedestals.Laser is passed thro mobile equipment and adjustments carried out as per requirement.

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LASER ALIGNMENT KITLASER ALIGNMENT KIT

Centering of Bores of diaphragms,pedestals,shaft seals etc

Source Laser device fixed in one extreme end pedestalReceiver end device fixed in other extreme pedestal.Special fixtures used for centering of intermediate pedestals.Online adjustment possible.

Alignment of RotorsCan cater to Coupling Dia from 100 mm to 1200 mm.Alignment Device fixed on couplings to be alignedTotal misalignment is indicated by just 60 degree rotation of Rotors.Misalignment values as well as correction required indicated in display.

Salient AdvantagesSaving in Cycle time.Accuracy of Measurement.Indication of correction factors.

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 39

LASER ALIGNMENT KITLASER ALIGNMENT KIT

CONCLUSION

The Laser Alignment kit is a useful equipment that is State of the Art in Technology and can be used very effectively in Turbine activities at high precision and reduced cycle time, as has been proved in Kudankulam site.Hence extensive use of this equipment has to be practiced.

Page 40: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 40

ORBITAL WELDINGORBITAL WELDING

Purpose – To provide leak proof joint between Tube to tube sheet in Condenser in addition to Forced expansion

Process – GTAW without filler wire addition

SIGNIFICANT ASPECTS

Material-Titanium

Large Qty of welding

Welding in position & at site

Material supply by Russians

TITANIUM TUBES

Grade : ASTM B 338 Gr2

Tube Sheet : 35 + 5 mm thick

Material : ASTM A516Gr 70 + ASTM B 265 Gr 1 CLAD

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ORBITAL WELDINGORBITAL WELDING

Why Titanium is used?

Provides excellent resistance to general and localized attack under most oxidizing, neutral and inhibited reducing conditions in aqueous environments.

Corrosion Resistance due to stable, protective strongly adherent oxide film which forms instantly when a fresh surface is exposed to air moisture.

This film is transparent and not deducted by visual means.

Titanium resist corrosion by sea water to temperature as high as 260 0 C.

Even exposed to sea water for many years at a depth of over a mile shows no measurable corrosion.

Provides over 25 years of trouble free sea water service for chemical refinery de-salination and nuclear industries

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ORBITAL WELDINGORBITAL WELDING

Has the ability to resist erosion by high velocity sea water

The presence of abrasive particles such as sand has only a small effect on the corrosion resistance of Titanium

Production began in the late 1950s

Most widely used titanium is commercial pure (99.5 % Ti)

Manufacturing Process

Ingot →slab → Hot strip → cold strip → Slitting → Forming → TIG Welding → Stress relieving → Eddy Current & Ultrasonic testing

Page 43: Tech. Day Presentation

Tensile, flare, flattening & reverse flattening

Visual InspectionCleanliness, ID, OD, Surface condition, end condition and marking.

Tube to tube sheet joiningContact Rolling (0 to 5 % wall thinning for a length of 10 mm)

Orbital Welding – For highly reliable leak tightness

Forced Rolling (8 to 10 % wall thinning for a length of 25mm)

Physical TestingORBITAL WELDINGORBITAL WELDING

Page 44: Tech. Day Presentation

PROCESS FLOW CHARTFront / Rear end tube sheet cleaning – wire brush mounted in portable drilling machine

followed by acetone

Visual inspection

Titanium tube insertion

Initial cleaning before contact rolling

Initial contact rolling up to 10mm

Sh 1 of 3

Page 45: Tech. Day Presentation

End facing of tube & tube sheet up to 0.05 mm

Welding

Visual inspection

Rectification of repair work

Final expansion 8 to 10 % by lubricating SAE 40 oil

Excess length trimming in the rear side

PROCESS FLOW CHART CONTD… Sh 2 of 3

Page 46: Tech. Day Presentation

Tube tightness test by MAUS Gun G-150

Dye Penetrant testing

Final cleaning by acetone

PROCESS FLOW CHART CONTD… Sh 3 of 3

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TUBETUBE SPECIFICATIONSPECIFICATION

Page 48: Tech. Day Presentation

TUBE INSERTION AT KODAMKULAMTUBE INSERTION AT KODAMKULAM

Page 49: Tech. Day Presentation

FRONIUS MODEL - FPA 2000 (AUSTRIAN MAKE)

PROGRAMABLE ORBITAL WELDING MACHINES

Page 50: Tech. Day Presentation

AFTERAFTER TUBE INSERTIONTUBE INSERTION

Page 51: Tech. Day Presentation

TUBETUBE SHEET PROTECTIONSHEET PROTECTION

Page 52: Tech. Day Presentation

Welding parameters for FRONIUS MODEL - FPA 2000

Process : GTAW (Automatic )

No of weld passes 1Argon Gas flow rate 4 to 6 ltr /min

Pre Gas time T10 30 Sec Post Gas time T11 30 Sec Pre Fusion current I21 90A Pre fusion current time T21 0.1Sec Pulse current I22 90A Time of pulse current T22 100msec

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USE OF HYDRAULIC OPERATED TORQUE CONTROLLED BOLT USE OF HYDRAULIC OPERATED TORQUE CONTROLLED BOLT TIGHTNING KITTIGHTNING KIT

OBJECTIVETo adopt a safe ‘State of the Art’ methodology in bolt stretching of coupling bolts of TG Couplings.

GENERAL COUPLINNGS IN TGHP Tubine to IP TurbineIP Turbine to LP TurbineLP Turbine to Generator Shaft

REQUIREMENTThe coupling bolts which are like pins, having a clearance of 0.03mm diametrically, have to be stretched up to 0.55 mm ,depending on the bolt dimensions to ensure uniform tightening .

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USE OF HYDRAULIC OPERATED TORQUE CONTROLLED BOLT USE OF HYDRAULIC OPERATED TORQUE CONTROLLED BOLT TIGHTNING KITTIGHTNING KIT

Prevalent practiceNut of the Coupling bolt is tightened by a box spannerLeverage applied on end of the spanner by EOT crane through slings.Differential expansion monitored by Dial Gauge positioned at bolt ends.

Sources of ErrorDial gauge at the nut end has to be fitted with a long extension rod,which may lead to error in reading.Disturbances in the nut also can lead to erratic readings.

Safety element

The whole stretching operation dependent on skill of the Fitter and EOT Crane operatorFine movements in EOT Crane not possibleDanger of slipping/shearing always present.

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USE OF HYDRAULIC OPERATED TORQUE CONTROLLED BOLT USE OF HYDRAULIC OPERATED TORQUE CONTROLLED BOLT TIGHTNING KITTIGHTNING KIT

RECOMMENDATIONHydraulically operated Torque controlled Bolt tightening kit can be used.Manufacturing Unit to specify Torque tightening values of individual couplings.

ADVANTAGESNo error in reading.Uniformity in bolt stretchingSafe for the working personnelSafe for the equipment

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Power Sector Western Region

IMPROVED PROCESSES

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 57

ALL-VOLATILE & OXYGENATED TREATMENTALL-VOLATILE & OXYGENATED TREATMENT

`

AVT : The basic idea of AVT is to minimize corrosion & erosion corrosion in the low temperature region by using deaerated high purity water with elevated PH. The actual PH range depend on cycle metallurgy In absence of Oxygen, the primary reaction of iron dissolution is inhibited by increasing PH. The solubility of ferrous hydrazine rises with increase in temperature and then decreases with steep drop to the solubility of magnetite between 200 – 250 0C. This results in undesirable magnetite deposit in this temperature range.

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ALL-VOLATILE & OXYGENATED TREATMENTALL-VOLATILE & OXYGENATED TREATMENT

`

To maintain the solubility of ferrous hydroxide in feed water below or equal to that of magnetite at 250 0C and to exclude the possibility of over saturation, a minimum PH of 9.6 should be maintained. A PH of 10 would be even better. Hydrazine acts both as a O2 scavenger & corrosion inhibitor by formation of ferrous oxide hydrate.

OXYGENATED TREATMENT :This process uses oxygenated high purity water to minimize corrosion & erosion corrosion in the feed water train. Oxygen, Hydrazine peroxide, air are used as oxidants

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ALL-VOLATILE & OXYGENATED TREATMENTALL-VOLATILE & OXYGENATED TREATMENT

`

Oxygen level should be 30-50 ppb for drum units and 30-150 ppb for Once Through Units. Ph level shall be 9-9.6 at Drum units and 8-8.5 for Once Through Units In oxygenated system, p rotective layer consists of Magnetite(FE3O4) and Hematite(FE2O3) layers For temperature ranges upto 250 0C the addition of oxygen allows the formation of oxide protective layer which have a very low corrosion product release rate in the following water

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ALL-VOLATILE & OXYGENATED TREATMENTALL-VOLATILE & OXYGENATED TREATMENT

AL L VOLATILE TREATMENT (AVT)

• Ferrous or mixed feedwater train

• Cation conductivity 0.2-0.4 μS/cm

• pH 8.8 – 9.6 (Dependent on feedwater metallurgy)

Fe 10ppb N2H4 ( >3x02)

O2 <5ppb NH3 ( 0. 15-2 . 3 ppm)

Fe <2 ppb O2 ( >30 ppb ) O2 ( >30 ppb )

NH3 ( 20 -70 ppb )

OXYGENATED TREATMENT (OT)All ferrous feedwater train Cation conductivity < 0. 15 μS /cmpH 8.0 – 8.5

HP Heaters

Boiler BFP DA LP Heaters

CP CEP Condenser

HP Heaters

BFP

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 61

LP BYPASS SYSTEMLP BYPASS SYSTEM LP BYPASS SYSTEM

MODIFICATION CARRIED OUT IN OLD LPBP SYSTEM

In case of Turbine trip, direct command will be issued to LP Bypass valves for opening upto 45% for 3 secs.

It is expected that within this 3 secs., the spray valves will open and the spray water pressure will be achieved.

However, if the spray water pressure has not reached a value of 5 kg/cm2 within 3.5 secs., or the condenser wall temperature has become more than 90 0C, the LP Bypass trip command will be issued

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LP BYPASS SYSTEMLP BYPASS SYSTEM

The sensing of pressure is done by installation of additional pressure transmitters at the downstream of spray water valves

The modification was implemented first in Vindhyachal U#10 and two occasions since the modification, the turbine has tripped and LP Bypass valves opened within 5 secs thereby saving the boiler trip

LBPB SYSTEM FOR NEW 250 MW SETS

To address this issue, now BHEL, Hwr has gone for a new High Pressure LP Bypass system which has much better response time. Such system have been supplied at 1 x 250 MW Parli, 1 x 250 MW Paras, 4 x 250 MW JPL and 2 x 250 MW Bhilai sites.

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 63

LP BYPASS SYSTEMLP BYPASS SYSTEM

The logic provided for the operation of the LB Bypass valves are similar to that of the older low pressure LPBP valves. However, the following are the new features of High Pressure LPBP valves

The LPBP valves on sensing increase HRH Pressure, automatically opens without looking for adequate water pressure

For the water injection spray control valves, two curves have been implemented, one for control and the other for protection based on down stream pressure of LPBP valves.

Page 64: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 64

LP BYPASS SYSTEMLP BYPASS SYSTEM If the actual water injection flow is less than flow

corresponding the protection flow, then the LPBP valves closes on water injection flow protection.

The following problems have been noticed in the new system

As per the water injection curve, a continuous water flow is required to the system which is unnecessary and wasteful.

The spray water flow element and flow transmitter is showing 0 reading upto 50% of spray control valve opening.

The problem has been taken up with BHEL, Haridwar

Page 65: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 65

LP BYPASS SYSTEMLP BYPASS SYSTEM

Conclusions :

The new High Pressure system is working satisfactorily and therefore, the boiler tripping due to reheater protection in the new system has been avoided in the recently commissioned units.

By implementing the modification in the old units as done at NTPC Vindhyachal U#9, 10, the problem of the old units can also be resolved.

Page 66: Tech. Day Presentation

Power Sector Western Region

BEST PRACTICES

Page 67: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 67

CARD BOARD BLASTING OF LUB OIL AND CONTROL OIL LINES OF STEAM TURBINES

GENERAL PRACTICE

Only mechanical cleaning is done before start of oil flushing for lub oil and control oil system of steam turbines.

BEST PRACTICE

Exhaustive card board blasting along with mechanical cleaning is carried out for all the control and lub oil system before start of oil flushing.

This practice is being followed in almost all the sites now.

ADVANTAGES

Effective cleaning and time reduction.

Best Practices, TSX PSWR

Page 68: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 68

USE OF PORTABLE CENTRIFUGE DURING LUB OIL FLUSHING OF ROTARY MACHINES

GENERAL PRACTICE

Generally oil flushing were carried out at ambient temperature without any centrifuging arrangement for rotary machines such as BFP, ID Fans, FD Fans and Mills.

BEST PRACTICE

Oil flushing is carried out with portable oil centrifuge having in-built heating arrangement .

ADVANTAGES

Effective cleaning and time cycle reduction.

Best Practices, TSX PSWR

Page 69: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 69

CHEMICAL CLEANING OF PRE BOILER SYSTEM WITH CEP

GENERAL PRACTICE

Carried out by using temporary pumps, tanks and piping along with boiler acid cleaning setup

BEST PRACTICE

Existing CEP and Hotwell are used for the purpose of circulation in the entire system

ADVANTAGE

Effective cleaning of the entire system with minimum number of temporary loops

Cost and time cycle reduction

Best Practices, TSX PSWR

Page 70: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 70

USE OF DEAERATOR AS MIXING TANK FOR PRE-BOILER FLUSHING

GENERAL PRACTICE

Mixing tanks and associated pipings are arranged for carrying out the pre boiler flushing activities.

BEST PRACTICE

For industrial sets, Deaerator itself is used as mixing tank for carrying out chemical cleaning of pre-Boiler system.

This results in cost and time cycle reduction.

Best Practices, TSX PSWR

Page 71: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 71

CHEMICAL CLEANING OF BOILER (WW, SH) AND MS LINES IN INDUSTRIAL PROJECTSGENERAL PRACTICE

Stages are : Alkali boilout, Acid cleaning and passivation

BEST PRACTICE

Alkali flushing, Citric acid cleaning, passivation of the entire system

ADVANTAGE

Chemical cleaning activities can be completed even before Boiler light up

Since both SH and MS lines are acid cleaned & steam blowing cycle is considerably reduced

Cost and time cycle reduction

Best Practices, TSX PSWR

Page 72: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 72

CHEMICAL CLEANING OF HSD AND NAPHTHA LINES IN CCPP

GENERAL PRACTICE

Cleaned by card board blasting

BEST PRACTICE

Citric acid cleaning with passivation

ADVANTAGE

Where the length of HSD and Naphtha lines is more than 500 meters cardboard blasting shall not be very effective. Hence, citric acid cleaning is a most effective way of ensuring cleanliness of the entire piping

Time cycle reduction and trouble free operation

Best Practices, TSX PSWR

Page 73: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 73

USE OF THERMIC FLUID HEATER FOR COMMISSIONING ACTIVITIES IN GREEN FIELD PROJECTS

GENERAL PRACTICE

Auxiliary boiler is used for generation of steam for pre-commissioning activities like flushing of Boiler Feed Line, Condensate Lines, Drip Lines etc.

BEST PRACTICE

Thermic fluid heater is used in green field projects in place of auxiliary boiler for carrying out chemical cleaning activities.

This results in cost and time saving.

Best Practices, TSX PSWR

Page 74: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 74

ACID CLEANING WITH EDTA

GENERAL PRACTICE

Generally HCL is used for acid cleaning of main boiler.

BEST PRACTICE

HCL is replaced by EDTA for all green field projects especially, where auxiliary steam is not available.

This is safe, environment friendly and reduces time cycle.

Best Practices, TSX PSWR

Page 75: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 75

PROVISION OF ADDITIONAL INTERSTAGE VALVES FORSTEAM BLOWING

GENERAL PRACTICE

Interstage valves are not used during steam blowing operations resulting in three to four days shut down for start of subsequent steam blowing operations.

BEST PRACTICE

Additional temporary valves are used at Main Steam HP Bypass lines, CRH Lines during steam blowing operations.

This has resulted in cycle time reduction.

Best Practices, TSX PSWR

Page 76: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 76

CONTINUOUS STEAM BLOWING IN CCPP

GENERAL PRACTICE

Puffing method is used due to limitation of fuel firing system

BEST PRACTICE

Continuous blowing method (30 minutes) is used in stages

ADVANTAGE

Effective cleaning and time cycle reduction

Best Practices, TSX PSWR

Page 77: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 77

HIGHER STEAM BLOWING PARAMETERS

GENERAL PRACTICE

Steam blowing is carried out at 40 Kg / sq cm and 300 – 350 deg C

BEST PRACTICE

Steam blowing carried out at 50 Kg / sqcm and 370 – 400 deg C

ADVANTAGE

Effective cleaning due to higher disturbance factor at elevated parameters

Time cycle reduction

Best Practices, TSX PSWR

Page 78: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 78

USE OF FRESH LUB OIL BOTH FOR FLUSHING AND REUSE IN ALL INDUSTRIAL SETS

GENERAL PRACTICE

Flushing oil is used for oil flushing operation, fresh oil is used for normal operation

BEST PRACTICE

After cleaning of entire lub oil system by cardboard blasting fresh oil is used both for flushing and normal use

ADVANTAGE

Cost and time cycle reduction

Best Practices, TSX PSWR

Page 79: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 79

AIR LEAK TEST OF LUB OIL, CONTROL OIL, AND CONTROL FLUID SYSTEM

GENERAL PRACTICE

No separate test conducted before start of flushing resulting in leakage of oil / fluids

BEST PRACTICE

Entire system is pressure tested with compressed air at 5 to 6 Kg/sqcm before start of flushing operation

ADVANTAGE

Leakage of oil and control fluid is minimised

Cost and time cycle reduction

Best Practices, TSX PSWR

Page 80: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 80

GENERATOR SEAL OIL FLUSHING

GENERAL PRACTICE

Seal oil flushing is done for the site erected pipes upto the inlet nozzle in the end shield

BEST PRACTICE

Pre-fabricated pipes from the end shield upto seal ring inlet are also included in the final stage of flushing.

ADVANTAGE

Avoids damage to Generator seal from the entrapped foreign material.

Best Practices, TSX PSWR

Page 81: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 81

HYDRAULIC TEST OF LUB OIL, CONTROL OIL AND SEAL OIL LINES

GENERAL PRACTICE

Jacking oil pumps were used for carrying out hydraulic test of lub oil, control oil and seal oil line after flushing.

BEST PRACTICE

AC seal oil pimp is used for the purpose of hydraulic test of the above system.

ADVANTAGE

Avoids damage to Jacking oil pumps.

Best Practices, TSX PSWR

Page 82: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 82

CONDENSER MASS FLUSHING

GENERAL PRACTICE

Cleaning of condenser is normally carried out during steam dumping operation

BEST PRACTICE

Condenser tubes are thoroughly flushed through high pressure jets (fire fighting water) before commissioning of CEP

ADVANTAGE

Duration of steam dumping operation reduced

Cost and time cycle reduction

Best Practices, TSX PSWR

Page 83: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 83

CLEANING OF VACUUM PUMP SUCTION LINES

GENERAL PRACTICE

No structured cleaning is envisaged except draining the system through drain valves (NB50) during initial commissioning of vacuum pumps

BEST PRACTICE

Vacuum pumps suction lines are throughly cleaned through cardboard blasting before commissioning of vacuum pumps

ADVANTAGE

Smooth trouble free operation

Damage of vacuum pumps due to entry of foreign material is avoided

Best Practices, TSX PSWR

Page 84: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 84

OLTC COMMISSIONINGGENERAL PRACTICE

OLTC is commissioned normally after attaining continuous operation of unit, i.e., CW system has been put into service for prolonged period

BEST PRACTICE

OLTC is commissioned either

Immediately after running of CW pump or

Before conductance of PG test after thorough cleaning of condenser tubes

ADVANTAGE

Collection efficiency of balls increase

Trouble free condenser operation

Best Practices, TSX PSWR

Page 85: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 85

SELF CONTAINED BEARING COOLING ARRANGEMENT AT EPC PROJECT

GENERAL PRACTICE

Lub oil coolers for ID, FD and PA Fans are kept charged through the bearing cooling water system

BEST PRACTICE

In EPC project where due to certain circumstances there is a delay in commissioning of Cooling Water system a separate self contained cooling arrangement (Sintex tank, pumps and suitable hoses) to facilitate initial commissioning

ADVANTAGE

Trial operation of all major boiler auxiliaries can be completed by this method leading to time cycle reduction

Best Practices, TSX PSWR

Page 86: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 86

PRE ERECTION CHECKING OF BUS-DUCTS

General Practice

Bus-ducts are cleaned and erected

Commissioning jobs taken up later

Best Practice

While at ground, check tightness of all electrical connections of heaters, thermostats etc

Check heaters healthiness and adjust thermostat tripping points easily now

Check drain pad holes before lifting so that any corrections, if required can now be done easily

Trial assembly of Bus-duct structure on ground before erection

Avoids difficulty in commissioning / troubleshooting

Best Practices, TSX PSWR

Page 87: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 87

TURBINE X-CRITERIA

General Practice In X1 criteria for turbine rolling, main steam inlet temperature to

turbine has been used for criteria calculation. During any boiler trip and restart, X1 criteria gets fulfilled even though boiler outlet temperature is less. This leads to cold steam entering the turbine.

.

.Best Practice

Additional criteria X11 introduced using Temperature before HP bypass.

Best Practices, TSX PSWR

Page 88: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 88

ADDITIONAL TRIPPING DURING ATT

General Practice Tripping criteria during conductance of ATT does not include many

vital trip inputs

.

.Best Practice

Conditions like MFT, Turbine Bearing temperature VH, axial shift VH, vacuum low, cold gas temp trip, seal oil temp trip etc are added

Best Practices, TSX PSWR

Page 89: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 89

COMMISSIONING OF ATRS, ATT & AUTOSYNCHRONIZER

General Practice

Normally, ATRS, ATT and Auto-synchroniser are getting commissioned as pending points and not as a part of normal plant commissioning.

So after the ‘pending point’ is cleared, customer is normally not using the system.

Best Practice

We are putting efforts for commissioning these system in the first rolling

synchronisation itself.

Recently at Bhilai and Tata Trombay, ATRS and Auto-synchroniser have been commissioned during first few start-ups.

At Tata Trombay, ATT is also commissioned.

Best Practices, TSX PSWR

Page 90: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 90

DC EOP AND SOP LATCH RELAY

General Practice Lub Oil pressure low switch starts DC EOP through max system

SLC latch relay contract..

.

Best Practice

SLC latch relay contract in DC EOP and SOP cabinet looped so that lub oil pressure low switch contact starts DC EOP and SOP directly, bypassing MAX system SLC ON.

This safeguards machine in the event of AC as well as failure of max system

Best Practices, TSX PSWR

Page 91: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 91

AUTOSYNCHRONIZATION

General Practice As per circuit configuration, auto synchronizer after fulfilling its set

condition directly closes the Generator circuit breaker..

.Best Practice Additional contact of check synchronization relay wired up in auto

synchronization circuit. Here autosynchroniser setting are coordinated with setting of check synchronizing relay so that autosynchroniser and check synchronization relay operates at the same time.

This helps in safeguarding the machine during malfunctioning of autosynchronizer.

Best Practices, TSX PSWR

Page 92: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 92

AUTOSYNCHRONIZER TESTING

General Practice

As per normal practice, autosynchronizer is tested and its output command is verified within the panel terminals..

Best Practice

Autosynchronizer is tested in cold condition with supply of PT voltages through injection kit and actual Generator breaker closing (ensuring that isolators are open)

This helps in optimization of autosynchronizer setting more correctly and also total circuit gets checked.

Best Practices, TSX PSWR

Page 93: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 93

USE OF MULTIPLE FILTRATION MACHINES FOR TRANSFORMER DRYOUT

General Practice One Oil filtering machine (about 6 KL capacity) engaged for dryout

Best Practice More than one such machine put in parallel operation to optimally

utilise transformer drain header flow capacity

Advantage Cycle time reduced around 50%

Best Practices, TSX PSWR

Page 94: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 94

TURBINE BEARING METAL TEMPERATURE CHECKING

General Practice

As per normal practice, cabling from bearing metal temperature JB to control room/Cold Junction Compensation(CJC) JB are checked after installation of thermocouple in bearings..

.Best Practice

Before installation of thermocouples in bearing, signal upto DCS checked by heating the thermocouple tag wise.

This ensures correctness of connection, readings and also ambiguity of polarity change is avoided.

Best Practices, TSX PSWR

Page 95: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 95

DAVR DUMMY LOAD TESTING

General Practice As per normal practice, the AVR/DAVR dummy load testing is

carried out at site with the help of 500W lamp or any available resistive load..

.Best Practice

Dummy load testing is carried out with same type of resistive load which is identical in ratio to that of factory testing. With this type of testing, exact and identical readings with factory can be ensured.

Customer as well as commissioning engineer gets better confidence on DAVR working.

Best Practices, TSX PSWR

Page 96: Tech. Day Presentation

09/04/23

Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 96

PAINTING OF TRANSFORMERS AND BUS-DUCTS

General Practice

Painting works for busducts and transformers are attempted at very late stages

Becomes difficult because of shutdown requirement and thus opportunity may not be there

Best Practice

At least Station transformer and its busducts may be painted immediately after erection completion (before first charging). This transformer hardly goes into shutdown later

Better to paint the other transformers and busducts as well as soon as possible before charging

However, customer opinion / permission may be required since they may insist on painting only after all works are completed

Best Practices, TSX PSWR

Page 97: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 97

SEQUENCE STARTUP OF HT DRIVES

General Practice All HT drives are generally started individually during first

commissioning of the drives This lead to a pending point as we do not get suitable opportunity to

commission the HT drives in sequence mode

Best Practice

All the HT drives to be started in sequence during first startup of the any HT drive

Best Practices, TSX PSWR

Page 98: Tech. Day Presentation

Power Sector Western Region

Process improvements Adopted During Overhaul by PSWR-SAS Nagpur

Page 99: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 99

Introduction

Implementation of Best Practices during Overhauling

of T.G. has resulted into the following -

Overhauling cost reduction.

Reduce overhauling periods.

Improvement in quality.

Introduce latest technologies.

Improve customer satisfaction

Page 100: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 100

Implementation of Best practices

Use of latest technology like induction heating for dismantling and assembly of turbine.

Unit de-synchronization at 480 ºC of HP shaft temp by decreasing the load before shut down..

Turbine oil pump stop at 125ºC (HPS temp).

Barring gear stop at 125ºC (HPS temp).

To initiate overhauling activities as soon as machine comes to barring gear.

Decoupling of Generator rotor from turbine rotor and put back turbine rotor in barring.

Start dismantling of generator and O/H activities thereafter.

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Review by Site and follow-up from HQ

Site reviews all activities minutely

Time taking processes, idle times between activities, delay in arranging spares and mobilization of experts from units etc are identified well in advance.

HQ also involves in reviewing processes and all important issues and HQ inputs are duly incorporated on activity planning at site.

Reduction in overhauling duration to the target schedule is attributed to meticulously planning and follow-up of critical activities, which is accomplished in a shortest duration.

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Strategic Planning List out the History of past problems

Pre-overhaul survey record.

Analyze Present running behavior.

Input from MOU’s and utilities.

Timely arrange experts service from MOU’s

Milestone based review.

Mobilization of resources 3 days before start of Overhaul.

Scheduling of sequential & parallel activities

Identification of idle time & to avoid them by detailed planning in advance

All the anticipated spares required for completion of the overhauling work arranged at T.G. Floor before start of the work.

Page 103: Tech. Day Presentation

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Generator work starts within 36 hrs of De-synchronization

0000 hrs : De-synchronization (HP shaft temp at 480 Deg.C)

17.5 hrs : Barring gear stop (HP shaft temp at 400 Deg C)

17.5 hrs. to 20.5 hrs:

AOP stop

Lub oil to brg. 5,6,7 blanked & brg. 4 minimized

LP-Gen coupling decoupling

Hand barring will continue during this period

20.5 hrs : B/G re-started

With this practice Generator rotor thread out work starts within 36 hrs of de-synchronization.

Page 104: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 104

Procedure for decoupling of LP-Generator in hot conditions

Turbine is on Turning Gear. JOP in service, AOP in service.

Loosening of pedestal cover bolts, removal of Vibration probes.

Close turning gear valve to reduce the speed. Simultaneously loosen and remove pedestal cover bolts.

When Turbine speed becomes zero. Stop AOP while JOP is continuously kept in service. Continue Hand Barring.

Remove pedestal 4 cover. Close Lubricating oil throttle valve to the minimum possible.

Simultaneously blank lub oil supply to bearing 5,6 and 7 by putting gasket in lub oil supply line. (parallel, by 3 gangs). Keep watch on bearing 1,2 and 3 metal temperature and simultaneously do hand barring.

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Put tin sheet/polythene to cover on bearing 4. Start EOP and continue hand Barring.

Loosen LP-Generator coupling bolts and decouple LP-generator by continuing hand barring.

Shift generator rotor away from turbine Stop EOP and Adjust brg. 4 lubricating oil throttle valve to normal. Put pedestal cover back and start EOP & barring gear.

Dismantling & prepare for rotor thread out.

At the time of rotor thread out, stop turning gear again and stop EOP. Remove pedestal 4 cover.

After thread out put pedestal 4 cover back. Turbine on Barring gear with AOP in service till HP shaft temp comes to 125 deg C .

Note: Jacking oil pump is throughout kept in service.

Procedure for decoupling of LP-Generator in hot conditions

Page 106: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 106

PSWR’s Best records on TG overhauls

Overhauling of IP-LP Turbine & Generator including LP Turbine blades MPI have been carried out in record lowest time of 8½ days barring to barring. (13 days Bar to Bar) on year 2007 at 250MW U#2 Dahanu TPS.

Overhauling of LP Turbine & Generator have been carried out in record lowest time of 9 days barring to barring. (15 days Bar to Bar) on year 2005 at 250MW U#2 Dahanu TPS . This was achieved as an exceptional case to avoid power problem in Mumbai.

Overhauling of HP- LP Turbine & Generator including HP rotor replacement & HP/IP coupling hole reaming, LP free standing blades MPI & NFT along with bearings 1,2 & 4 replacement have been carried out in record lowest time of 13 days baring to barring. (18 days Bar to Bar) on year 2006 at 250MW U#1 Dahanu TPS.

Page 107: Tech. Day Presentation

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Overhauling of IP-LP Turbine & Generator including LP Turbine blades MPI & NFT have been carried out in record lowest time of 12 days barring to barring. (17 days Bar to Bar) in year 2008 at 250MW U#2 Dahanu TPS.

Unit-3 HP Module overhauled in 14 days barring to barring (19days bar to bar) in year 2006 at 200MW U-3 KSTPS NTPC Korba.

Capital Overhauling of HP-IP-LP Turbine & Generator including HP rotor replacement & HP/IP coupling hole reaming, LP free standing blades MPI & NFT have been carried out in record lowest time of 35 days barring to barring in year 2008 at 500MW U#8 NTPC VSTPS Vindhyachal .

PSWR’s Best records on TG overhauls

Page 108: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 108

Schedule comparisonSl.

No Capacity (MW)

Capital Overhauling TG SET (Barring to Barring)

Previous Best Record Present Record

1 500

(All three module + Gen)

36 Days Unit-6, NTPC,KSTPS Korba on year 1996

35 days Unit-, NTPC, VSTPS Vindhyachal on year 2008

2 250

(HP-LP&GEN)

30 Days Unit-U-2 REL, Dahanu TPS on year 2002

13 days Unit-U-2 REL, Dahanu TPS on year 2006

3 250

(IP-LP&GEN)

- 8½ days Unit-U-2 REL, Dahanu TPS on year 2007

4 200/210

(HP Module)

28 Days Unit-2 NTPC KSTPS on year 2001

15 Days Unit-3 NTPC KSTPS on year 2006

Page 109: Tech. Day Presentation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 109

Conclusion

A benchmark on record minimum duration in KWU design TG set overhaul could be achieved.

It was the determination, commitment, monitoring and follow-up of associated activities that ascertained to achieve a challenging target.

Working out activities well in advance with subcontractor agencies/ partners and round the clock execution of job with new strategies helped to meet schedule deadlines.

Work can be started as soon as machine comes to Barring gear.

Cooling Down period can be saved relatively by 4 days during the Generator overhauling.

Page 110: Tech. Day Presentation

Power Sector Western Region

IMPROVED SITE FACILITIES

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 111

Award of Enabling works and its construction takes considerable time, after receipt of confirm order. This delays posting of site staff and material management including posting of Construction Manager.

PSWR has decided to procure Porta Cabins with all amenities as replacement of Conventional Site office sheds.

This will be provided in all new sites like Satpura, Mauda, Chandrapur, Raigarh, Vindhyachal, Bela Ideal Energy including all forthcoming sites.

NIT has been floated and tender is likely to be finalized by end April 2009.

Porta Cabins - to overcome delay in site mobilisation

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Exploring Heights ..................... Setting Standards .................... Marching Towards ExcellencePower Sector Western Region 113

Advantages of Porta Cabins

1. Quick mobilization

2. Quick realization of mobilization advance from customer

3. Quick demobilization

4. Flexibility in use & can be installed as per the site condition

5. Environmental friendly due to cleanness & easy maintenance

6. Provide better facility to site staff

7. Light weight (Easy in handling and transportation)

8. Aesthetic look.

9. Durable and Termite proof

10. Seismic-resistant

11. Economical in long term because of repetition

12. Thermal Insulation

Porta Cabins - to overcome delay in site mobilisation

Page 114: Tech. Day Presentation