ENIT NO USHP-II/GD/24 OF 2020-21

Amount

Dismantling of Chequered Plates of Generator Floor and their stacking in the Power House Service Bay.

Dismantling of Upper Dome assembly.

Installation of Erection Devices (as supplied by the Turbine manufacturer at the time of erection) for dismantling / removing of Draft Tube cone (Upper and Lower) & Runner Assembly.

Dismantling of Adjusting rings of Draft Tube Cone.

Dismantling of Draft Tube Upper and the Lower Cone.

Installation of Bulk Head on Draft Tube Opening. Bulk head to be provided by J&K PDCL.

Dismantling of Permanent Magnetic Generator (PMG), disconnecting and opening of Excitation Leads. Extension Shaft, Slip Rings and the Bush Rocker Assembly.

Opening of all Oil, Water and Air and Grease Pipe lines of Turbine and Generator.

Jacking up of the Generator Rotor assembly and locking of all the Brake/ Jack units.

Dismantling of bearing oil coolers of all bearings, stator air coolers, vapour seal, etc.

Opening of Upper Guide Bearing (UGB) Pads followed by the dismantling of UGB cylinder as well.

Dismantling of Thrust Collar assembly, Thrust Mirror Disc and all the Thrust Bearing Pads.

Opening of the supporting plates of Regulating Rings after disengaging from the connecting rods of Guide Vane Servomotors.

Dismantling of the existing Shaft Sleeve assembly.

Dismantling of Runner Cone Assembly.

Dismantling of Runner Assembly.

Installation of Erection devices (as supplied by the Turbine manufacturer at the time of erection) for resting of Runner Assembly after decoupling of Runner Assembly and Turbine Shaft.

Lowering of Runner Assembly and carriage of same to service bay.

Dismantling of Guide Vane Levers, Guide Vane Links etc.

Dismantling of all the Turbine Guide Bearing Pads and storing them safely.

Dismantling of Top Air Guide / Baffles assembly.

Dismantling of Bottom Air Guide/ Baffles, Vapour Seal, etc.

Dismantling of Radial Jacks of Upper Bracket Assembly followed by dismantling of the Upper Bracket Assembly.

Decoupling of Turbine Shaft and the Generator Shaft assembly.

Lifting of Generator Rotor assembly from the Generator pit along with its Generator Shaft and placing it securely in the Service Bay.

Dismantling & Lifting of Lower Bracket assembly from the Unit pit followed by its placement in the Power House floor.

Dismantling of all the Guide Vanes and Guide Vane Servomotors, etc.

Dismantling of the Turbine Top Cover assembly including the Lower Fixed Labyrinth Ring.

Dismantling of the Turbine Shaft assembly.

Dismantling of the existing damaged Shaft Sleeve assembly.

Dismantling of MIV complete

Stacking and placement of dismantling parts at suitable safe place/service bay

POST-DISMANTLING INSPECTION & TESTING/ MEASUREMENTS:

Non-Destructive Testing of the various dismantled unit assemblies including the welded portions on the Bracket arms& Turbine Top Cover.

Liquid Penetrant tests shall be undertaken on the welded portions of the Generator Stator Frame to assess their healthiness.

Ultrasonic Testing of all the bearing pads of:

Ø Thrust Bearing assembly

Ø Upper Guide Bearing assembly

Ø Lower Guide Bearing assembly

Ø Turbine Guide Bearing assembly

Inspection of the secondary grouting and its bonding with the primary civil foundation at the Lower Bracket sole plates.

Inspection of the secondary grouting and its bonding with the primary civil foundation under all the Stator Sole Plates.

Inspection of all the dismantled Studs, Dowels, Bolts/ Nuts, Pins to identify their replacement by new ones.

Measurement of Runner diameters at the Labyrinth Rings on both Suction side as well as the Discharge side to check/ determine the ovality/ eccentricity besides the extent of erosion.

General Check-up of the profile of all the Runner Blades.

Measurement of the Diameters of both the Stationary Labyrinths engaged with Pivot Ring as well as the Turbine Top cover assemblies to check/ determine the ovality / eccentricity besides the extent of erosion.

Measurement of the dimensions including its top/ bottom Trunnion diameters as well as the feather heights of all the dismantled Guide Vanes.

Dismantling of all the Guide Vane bushes from the Pivot Ring assembly. However before their dismantling, diameters of all the pivot bushes shall be measured and recorded.

Dismantling of all the Guide Vane bushes from the Top Cover Bush Housings. However before their dismantling, diameters of all the pivot bushes shall be measured and recorded.

Carrying out physical inspection of MIV along with the seal and check list the works to be carried out at workshop

Checklist of all parts to be replaced / repaired.

REPAIR OF THE DISMANTLED ASSEMBLIES AT WORKSHOP:

Transportation of below mentioned assemblies from the powerhouse to workshop for essential repairs.

All the dismantled 24 No. Guide Vanes.

Dismantled Upper Draft Tube Cone assembly along with Bottom Stationary Labyrinth Ring assembly.

Dismantled Turbine Top Cover assembly along with Top Stationary Labyrinth Ring assembly.

Dismantled Spare Turbine Runner assembly along with its top as well as bottom moving labyrinth assembly.

Dismantled Pivot Ring Assembly.

Overhauling of Runner Blade assembly and Providing/ Fitting of upper & Lower rotating labyrinths of runner by new ones.

All the dismantled Guide Vane Bush Housings.

Replacement of Upper and Lower Labyrinth by new one

Pressure Relief Valve Assembly.

MIV Assembly complete.

Bearing Bodies

Overhauling of all the Guide vane bush housings, as required.

General refurbishment of all Guide Vane Bearing Bodies by polishing etc. and assembly of Guide Vane Bushes in the Bearing Body Housing assemblies using proper fit including the new Cup Seals and ‘O’-Rings.

Pivot Ring Assembly:

Manufacture of Fixed Lower Stationary Labyrinth Ring with Stainless Steel (13%-Cr; 4%-Ni) with machining to the designed tolerance limits.

General cleaning & polishing of liner surface of the Pivot ring assembly.

Repair of M.S. portion, Stainless Steel Liner and eroded holes of the Pivot Ring assembly by welding and grinding.

Procurement and Replacement of all Cup Seals

Replacement of 24 no. brass bushes by new one

Checking the bolt tightness of bottom liner plates as well as the bottom stationary labyrinth ring of Pivot Ring assembly.

Turbine Top Cover assembly:

Manufacture of Fixed Upper Stationary Labyrinth Ring with Stainless Steel (13%-Cr; 4%-Ni) with machining to the designed tolerance limits.

Testing of Turbine Top Cover assembly and identifying the areas for repairs.

Supply installation testing and commissioning of new turbine top coverfor 35 MW unit-II along with allied accessories and fittings.

Refurbishment of damaged top cover of 35 MW of unit-II complete in all respect.

Guide Vanes

Repair of top ,middle and bottom journals by welding and machining to achieve original size of guide vanes

Repair of feather portion of the guide vanes by welding, one layer of final welding to be done with hard facing electrode before grinding in order to achieve original profile as far as possible. Height of the feather shall be made as per requirement based on the distance of top and bottom liners or as per drawings.

Weld build up sealing surface of each guide vane throughout the length is required to be carried out followed by their machining on planer machine. Sealing strips should be parallel to the guide vanes axis and horizontal feather surface should be perpendicular to the guide vane axis.

Weld repair of collar to be done with Stainless Steel 309 electrodes and its machining on suitable lathe for maintaining the seat for bush.

Draft Tube Cone Assembly

Carrying out the repairs of the Draft Tube Cone with Providing and fixing of new labyrinth alongwith repairing of old one as per standard procedure that includes welding and precision machining

Turbine Shaft Sealing assembly

Manufacture of new Shaft Seal system (Rotating Sleeve & Stationary Bracket assembly). Installation of a new Shaft Sleeve on the Turbine Shaft assembly

Pressure Relief Valve Assembly:

Complete dismantling of the Pressure Relief Valve Assembly.

Repairing of all the eroded portions of the moving & stationary Seals by welding, grinding, machining and lapping. All bushes, Springs, ‘O’-Rings, Gaskets, Packing, Gland pack, Cup Seal required for repair shall be replaced by new ones. Providing and fixing of new oil piston cylinder.

Replacing of damaged PRV rod (shaft) as per sample

Painting of PRV body with two coats of synthetic enamel paint (Berger)

MIV Complete Overhauling of MIV along with repairs of moving and stationary parts

Dismantling of expansion joint, overhauling / repairing of S.S. sealing ring ( metal to metal ).maintenance sealing ring (metal to metal ) and fixed sealing ring , valve body drainage and air vent and rotor seal for term tightness

Overhauling / repairing of locking bolt of maintenance sealing ring along with cleaning of piston cylinder of servo motor and replacement of damaged cup seals

Overhauling / repairing of sliding bearing sleeve of shaft (rubber seal )

Replacement of stem seal between valve shaft and body

Replacement of MIV operating mech. Bushes linking servomotor

Overhauling of MIV operating mechanism including reconditioning of piston cylinder

Painting of MIV complete

Rebabitating of all Pads

Thrust bearing pads

Lower guide bearing pads

Upper guide bearing pads

Turbine guide bearing pads

Water Pipeline and greasing unit(Revamping of complete water pipeline system alongwith overhauling of compressor units including greasing units.)

REPAIR OF THE DISMANTLED ASSEMBLIES AT POWER HOUSE:

Thrust Bearing Assembly:

Blue-matching of rebabitated pads for checking quality of rebabitating with a surface plate.

Blue matching of the thrust collar bottom surface with the top insulation surface of thrust runner disc in the Service bay.

Thorough cleaning of all Thrust Bearing Oil Coolers and pressure testing of the same and assembly.

All gaskets and damaged fasteners required for the assembly

Upper Guide Bearing assembly:

Blue-matching of rebabitated pads with the corresponding journal surface on the Thrust Collar assembly.

Lower Guide Bearing Assembly:

Blue-matching of rebabitated pads with the corresponding journal surface on the Lower Bearing Journal on the Generator Shaft assembly.

Thorough cleaning of all Lower Guide Bearing Oil Coolers and pressure testing of the same and assembly.

All gaskets and damaged fasteners required for the assembly

Turbine Guide Bearing Assembly

Polishing of all the Turbine Guide Bearing Pads and blue-matching them with the corresponding journal surface on the Turbine Bearing Journal on the Turbine Shaft assembly.

Thorough cleaning of all Turbine Guide Bearing Oil Coolers and pressure testing of the same and assembly.

All gaskets and damaged fasteners required for the assembly

Guide Vane Servomotors & Regulating Ring assembly:

Overhauling/ Repairing of Guide Vance Servomotors and the Regulating Ring assembly.

Replacement of ‘O’-Rings and Cup Seals.

Replacement of eroded brass and bottom Pads by new ones.

Replacement of all Teflon Bushes by new ones.

Brake/ Jack Assembly:

Overhauling of Brake Jack assembly and its Pressure testing along with replacing of brake pads.

Any Cup-Seal observed to have been damaged shall be replaced.

Generator Stator Assembly

Thorough cleaning of the complete Generator Stator Core all along its periphery both inside as well as from its outside surface using a suitable cleaning agent viz MTO.

Thorough cleaning of the complete Generator Stator Winding overhang portions all along its periphery on both its connection-end side as well as from its non-connection end side using a suitable cleaning agent viz MTO.

Checking of Stator Slot Wedge tightening and its rectification. Checking for any looseness of whole top as well as bottom overhang insulation including packers and retightening of the same. Spare wedges and packers as available in the powerhouse stores shall be used for this work.

Carrying out ELCID testing of the Generator Stator core assembly and minor repair, if required.

Application of Loctite-290 compound on the two top-most as well as bottom-most stator core packets all around the periphery of the generator core.

Spray painting of Generator Stator Winding top as well as bottom overhang portion by Epoxy Red Gel paint using oxygen gas to avoid any ingress of moisture in the winding.

Spray painting of Generator Stator Core surface by Grey Becktol insulation paint using oxygen gas to avoid any ingress of moisture in the Generator.

Conducting the Dry-Out of the Generator Stator Winding assembly.

Carrying out ultrasonic testing of stator core

Carrying out X-Ray testing / Ultra violet testing / dye penetration test of stator core.IR and PI testing of stator core.

Carrying out Tan delta /power factor and capacitance measurement testing of stator core.

High Voltage testing of stator bars

Generator Rotor Assembly:

Dismantling of all the 10 No. Rotor Poles from the Rotor assembly.

Dismantling of all the Rotor Pole Coils from their respective Pole assemblies.

Thorough cleaning of all the dismantled Pole Coils as well as their Pole Shoe assemblies using a suitable cleaning agent viz MTO.

Spray Painting of all the cleaned Pole Coils by Epoxy Based Red Gel Paint using oxygen gas to avoid ingress of moisture.

Spray painting of all the pole shoe assemblies by Becktol Red insulation paint.

Reassembly of all the cleaned Pole Coils on their respective Pole Shoe assemblies and their packing up properly.

Carrying out electrical testing of all the assembled Generator Rotor Poles viz IR value, Impedance measurement, etc.

Reassembly of all the 10 No. Rotor Poles in their respective positions on the Rotor Rim assembly after driving their Pole Keys to the proper tightness.

Conducting the Impedance measurement of all the Rotor Pole Coils followed by their Polarity testing.

Completing the jointing of all the assembled/ tested Rotor Poles involving soldering and proper insulation.

Measurement of the Insulation Resistance of the Rotor Pole winding to check its final healthiness.

Overhauling of H.S. Motor / Pump assembly and cleaning of its filters and replacement of its wornout gaskets of pipe line

Conducting the Dry-Out of the Generator Rotor assembly.

Stator Coolers

Thorough cleaning of all Thrust Bearing Oil Coolers and pressure testing of the same and assembly.

All gaskets and damaged fasteners required for the assembly including its piping & Valves joints

Replacement of worn out inlet and outlet valves and overhauling of other Inlet & Outlet Valves 16 no' 4 '' Valves

Modification of stator coolers inlet side 8 no. for flushing purposes during running operation

Painting of all Stator Air Coolers using smoke grey Berger make synthetic super enamel paint.

Slip Ring Assembly (Machining of slip ring for removing of grooves and making surface smooth with thorough polishing of Slip Ring surface and spraying with insulation paint )

EOC Coolers

Thorough cleaning of all Oil Coolers along with water tubes and pressure testing of the same with assembly.

Replacementof all gaskets and damaged fasteners required for the assembly including its piping & Valves joints

Replacement of wornout inlet and outlet eight water valves and overhauling of other oil Inlet & Outlet Valves.

Thorough cleaning of oil tank inside and outside along with its cleaning of oil filters and its replacement , painting using smoke grey berger make synthetic super enamal paint.

Retubing of damaged EOC Coolers app. 200 no.

Painting of all EOC Coolers using smoke grey Berger make synthetic super enamel paint.

Providing ,installation ,testing and commissioning of 60 HP EOC motor along with 60 cusec pump assembly

Providing ,installation ,testing and commissioning of 200HP cooling motor along with 700 cusec pump assembly with necsaary modification in pump assembly and repairs to foundation.

Replacement of 16 no. NRV’s and Valves of water cooling pipelines

Power Transformer Coolers

Thorough cleaning of all Oil Coolers along with water tubes and pressure testing of the same with assembly.

Replacementof all gaskets and damaged fasteners required for the assembly including its piping & Valves joints

Replacement of worn out inlet and outlet valves of cooling system along with overhauling of other oil Inlet & Outlet Valves.

Replacement of damaged three no. PRV for three power transformers

Carrying out various tests on unit power transformers viz a viz Tandelta,Power factor and capacitance tests,D.C. winding resistance measurement , IR ,PI and short circuit impedance tests

Dissolved Gas analysis (DGA) Testing of the transformer oil of all the three units of 15 MVA , 11/132 KV power transformers of Unit-II

Spiral Casing and Stay Vanes:

Repair of Stay Vanes by welding & grinding.

Cleaning of Spiral casing, Stay Vanes, PRV branch and Discharge pipe with scrappers in order to remove rusting & other deposits to the maximum possible extent.

Painting of Spiral casing on its outer surface with one coat of primer and two coats of synthetic enamel paint of Berger make.

Draft Tube Cones and Guide Plates

Cleaning of both the Draft Tube Cones as well as the Guide Plates with scrappers in order to remove rusting & other deposits to the maximum possible extent.

Painting of both the Draft Tube Cones as well as the Guide Plates with first coat of Epilux-4 followed by two coats of Epilux-5 paint.

Replacement of 8mm Rubber Cord by a new one.

Painting Works (Cleaning and Painting of Thrust Bearing housing, Upper Bracket assembly, Radial Jacks, Chequered Plates of the Stator & Rotor.)

Trail Assembling

Trial assembly of Runner with Pivot ring and measurement of bottom labyrinths clearances.

Trial assembly of Runner with Turbine Top Cover and measurement of top labyrinth clearances.

Transportation of below mentioned repaired assemblies from workshop to the Power House for Reassembly of the Unit at Site

All the dismantled 24 No. Guide Vanes.

Dismantled Upper Draft Tube Cone assembly along with Bottom Stationary Labyrinth Ring assembly.

Dismantled Turbine Top Cover assembly along with Top Stationary Labyrinth Ring assembly.

Dismantled Spare Turbine Runner assembly along with its top as well as bottom moving labyrinth assembly.

Dismantled Pivot Ring assembly.

All the dismantled Guide vane bush housings.

Pressure Relief Valve assembly.

Checking of stationary level of Turbine Speed Ring assembly.

Re-assembly of Pivot Ring assembly in position.

Re-assembly of all Guide Vanes in the Pivot Ring assembly.

Lowering of Turbine Shaft assembly in the turbine pit using the erection device.

Assemblies of the repaired Top Cover assembly in position with replacement of all its old fasteners by new ones which are to be procured.

Re-assembly of all the Guide Vane Bush Housings in the top cover and replacement of its damaged fasteners by new ones which are to be procured

Assembly of Regulating Ring alongwith Connecting Rods of the Guide Vane Servomotors in the unit.

Lowering of Lower Bracket assembly along with Brake Jack assembly in position with all its fasteners duly tightened.

Lowering of Generator Rotor assembly in the generator pit supporting on the jacking pads.

Lowering of Upper Bracket assembly in position with all its fasteners duly tightened.

Re-assembly of Thrust Collar assembly on the Generator Shaft by shrunk fitting method. Checking the vertical movement of Thrust Collar assembly.

Reassembly of Thrust Runner Disc assembly, Thrust Pads, H.S. Lubrication system, etc.

Checking of rotational level of Generator Shaft and correcting the same

Coupling of Generator and Turbine shaft flanges.

Re-assembly of the Francis Runner assembly and its coupling with Turbine Shaft using new Coupling Bolts & Nuts.

Assemblies of all associated turbine components viz Guide Vane Servomotors, Guide Vane Lever & Link Mechanism.

Carrying out the combined rotational checks of the Turbine & Generator Shafts and correcting the alignment, leveling & equal load sharing of the Thrust Pads.

Centering of the shaft and setting of Bearing clearances in UGB, LGB & TGB in a concentric manner.

Checking of all oil pipe lines & charging of Governor.

Bedding & setting of all Guide Vanes with respect to steel liner of Top Cover and Lower Ring to achieve proper clearances.

Boxing up all Bearings including their oil & water pipe lines.

Complete assembly of Draft Tube Upper Cone including full tightening of all bolts.

Complete assembly of Lower Cone with full tightening of bolts.

Complete assembly of Adjusting Ring with full tightening of all the bolts.

Complete assembly of Shaft Sealing system including assembly of water pipelines.

Assembly of grease pipeline of Upper Bushes and Lower Bushes and assembly of water pipe line of Lower Bushes.

Complete assembly of oil bath of Thrust Bearing with full tightening of bolts.

Measurement of Insulation Resistance value of Stator and Rotor winding.

Spinning of the machine, dry out and then synchronizing/ loading of the unit.

Carrying out the Dry-out of the Generator with windage loss method till the satisfactory levels of IR & the PI values is achieved.

Voltage build-up and subsequent synchronization of the unit followed by loading in steps and checking the unit vibrations at every step till the unit reached the rated load. Carrying out the balancing of the unit at load, if & as required.

Carrying out the measurement of unit vibrations & Dynamic balancing of the unit as required.

MATERIALS REQUIRED (SPARES AND FASTENERS)

All general purpose consumables, D&H make Mo-309 SS welding electrodes, O-rings, general purpose fasteners, stainless steel shims, insulation paints, etc. required during the capital maintenance.

Supply of 210 LPM OPU cartridge pump alongwith bushings and couplings

Turbine Oil Servo-57

Northern Power Erectors Ltd