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| 1 | TURBINE AND ASSOCIATED COMPONENTS Draft Tube (DT) Bend : Complete Refurbishment, Design Modification & Re-protection by way of complete dismantling; grit blasting & surface preparation to SA 2.5 standard; weld repair of pitting, rust, and material scaling; re-machining of runner-side flange to remove heavy rubbing marks and restore geometric profile; implementation of modified hydraulic design studies using soft wares to optimize flow and minimize axial thrust; application of 2-coat high- build epoxy coating system and final painting as per hydro-mechanical corrosion protection standards (IS 101 / IS 5). All work includes necessary NDT tests as applicable |
| 2 | Runner Assembly: Complete Refurbishment, Re-metalling, Machining, HVOF Coating & Balancing by way of ultrasonic Testing (UT) for defect mapping; welding repairs for cavitation, pitting, and cluster discontinuity defects; re-metalling of areas, machining to restore original hydrodynamic blade profiles and critical dimensions; final grinding and polishing; application of HVOF (High Velocity Oxy-Fuel) WC-CoCr coating on all wetted surfaces for superior sediment erosion and cavitation resistance; Static and Dynamic Balancing on certified balancing machine to achieve ISO 1940-1 G2.5 grade or better. Includes all necessary WPS/PQR, heat treatment, and certification. |
| 3 | Fasteners & Hardware : Complete replacement of all fasteners (nuts, bolts, studs, and washers), seals, and gaskets associated with the Draft Tube assembly. New fasteners shall be of corrosion-resistant grade (e.g., ASTM A193 B7/B8) as per OEM specification for 03 nos. Draft Tube Assembly |
| 4 | Runner Cone & Retaining Studs: Supply of New Components Supply of 03 nos. new runner cone and retaining studs, designed to match the profile and coupling dimensions of the refurbished runner assembly. Components to be manufactured from certified material with machining to final dimensions. |
| 5 | Guide Vanes: Complete replacement of guide vanes for all three units by way of reverse engineering, Supply and installation, Testing and commissioning of new guide vanes. New vanes to be manufactured from CA6NM or equivalent stainless steel to required dimensional and geometric tolerances to restore functional sealing clearances and top/bottom running clearances. Application of HVOF (High Velocity Oxy-Fuel) WC-CoCr coating on all wetted surfaces for superior sediment erosion and cavitation resistance |
| 6 | Bush Carrier: Cleaning and Painting Cleaning (grit blasting), inspection, and application of corrosion-resistant paint system to the existing lower bush carrier housings. |
| 7 | Complete Replacement of Guide Vane Bushes of all 03 units by way of Supply, Installation, testing and commissioning of new bronze/ composite material bushes for all guide vane stems. Includes press-out of old seized bushes, bore honing, and precise installation of new bushes to achieve specified H7/g6 clearances for smooth operation. |
| 8 | Replacement of Guide Vane Levers/Link rod:Supply and installation of new guide vane levers/Link rods. Levers/Link rods to be manufactured to original dimensions with reamed pin holes to correct ovality and restore size/roundness |
| 9 | Locking Device (Ring Feeder): Supply and installation of new ring feeder locking devices for all guide vanes of 03 units |
| 10 | Lever Covers: Cleaning and Painting (derusting), straightening of dent marks, and application of corrosion-resistant paint system on existing lever covers. |
| 11 | Fasteners for Guide Vane Assembly: Complete Replacement of fasteners (high-tensile bolts, nuts, washers, pins) for the entire guide vane and linkage assembly for 03 units |
| 12 | O-rings and Seals for Guide Vane Assembly: Supply of complete seal kit including all O-rings, gaskets, and lip seals for the guide vane assembly, lower bush carrier, and lever covers for 03 units |
| 13 | Guide Vane (GV) Servomotor Assembly: Complete dismantling, inspection, and refurbishment of all three GV servomotors. which include honing of cylinder barrel; repair/chrome plating of piston rod; replacement of all seals, packings, wear rings, guide bushes, and linkage pin bearings; replacement of all high-pressure hose pipes and fittings; reassembly, stroke setting, and pressure testing. |
| 14 | Shaft Seal Assembly: Supply and installation of new shaft seal assembly (e.g., radial face seal, packing box) compatible with the new/refurbished turbine shaft dimensions and design |
| 15 | Turbine Guide & Thrust Bearing Assembly: Supply and Installation New Turbine bearing (Thrust and Journal pads with an enhanced design, increased load capacity, improved lubrication, and cooling), DE & NDE bearing (Generator side bearing) shall be supplied and installed. Scope includes: new babbitted thrust pads, new journal pads having Tin-based Babbitt, Grade 2 material refurbishment of cracked bearing housings (Units I & II), and replacement of all associated O-rings, seals, and fasteners. |
| 16 | Braking System: Complete dismantling and overhaul of the braking system for all 03 units which includes replacement of brake servomotors (submerged), all seals, brake springs, and brake pads/shoes; cleaning and painting of structural components; reassembly and functional testing |
| 17 | Main Inlet Valve (MIV) Butterfly type : Complete refurbishment of MIV and by pass valves which includes cleaning and repairing of defected parts, replacement of all seals, O-rings, fasteners, re-painting, checking of operation and final testing. |
| 18 | Turbine Shaft Assembly: Replacement & Refurbishment For Unit I & III: Design, engineering ,supply, manufacture, and installation of new turbine shafts including machining of all journals, couplings, and threads to match new runner and sleeve coupling design. Material certification and dynamic balancing included.Re-machining of spiral hub to match new/refurbished shaft dimensions and ensure perfect alignment. |
| 19 | Unit II: Repair and refurbishment of existing shaft. Includes: straightening check, machining of worn shaft collar, repair of centre hole, build-up welding and machining of damaged areas, and repair of runner coupling face-machining of spiral hub to match new/refurbished shaft dimensions and ensure perfect alignment. |
| 20 | Turbine and Auxiliary Control Panel (TACP): Complete replacement of all internal components damaged by water submersion which includes new contactors, new 24V relays, new master trip relays (03 nos.), new distribution MCBs, new terminal blocks, and replacement of operating levers for main switches. Existing main switches and MCCBs to be cleaned, tested, and retained. All internal wiring to be cleaned of oil contamination or replaced. Panel doors, cabinets, and external components to be cleaned and painted. |
| 21 | Sensors and Instrumentation: Complete Replacement Supply and installation of new sensors and instrumentation for all three units which Speed sensors, MIV proximity sensors, Machine Standstill proximity sensors, RTDs (for turbine and generator bearings), and associated junction boxes with terminal blocks. All sensors to be calibrated. |
| 22 | Cables: Replacement of Damaged Cables and Remediation- - Replacement of damaged 4-core, 2.5 sq. mm power cable at the 33 kV switchyard. Replacement of cable end terminations on the 33/0.415 kV step-down transformers with new heat-shrinkable kits. Supply installation & testing of Manual changeover for battery bank. Proper cable management for unused cables in trenches to be done.Any other cable found non- operational during the restoration is included |
| 23 | Turbine Lubrication Oil Pressure (TLOP) System: Complete Replacement of 03 units: Design, Reverse engineering, Supply, installation, Testing and commissioning new TLOP system for all three units. New system to include: digitally controlled operation, built-in oil chilling unit, duplex filtration system (target ISO 4406 cleanliness), AC & DC motors, hydraulic pumps, all valves (pressure control, flow switches), filters, connecting pipelines including first fill of oil and a new control Electric panel of suitable rating. The panel should be SCADA ready (with MODBUS protocol). |
| 24 | Generator Lubrication Oil Pressure (GLOP) System: Complete Replacement Design, Reverse engineering, Supply, installation, Testing and commissioning new GLOP system for all three units. New system to include: digitally controlled operation, built-in oil chilling unit, duplex filtration system (target ISO 4406 cleanliness), AC motors, hydraulic pumps, all valves (pressure control, flow switches), filters, connecting pipelines including first fill of oil and a new control Electric panel of suitable rating. The panel should be SCADA ready (with MODBUS protocol) |
| 25 | Hydraulic Power Unit (HPU) of Governing System: Complete Overhaul & Critical Component Replacement:- Complete overhaul of all three governor HPUs which includes dismantling, cleaning, and flushing of oil tank and all pipelines and hydraulic valves; complete, refurbishment of AC motors of all electronic/hydraulic components: Proportional Valves (Moog), Poppet Valves, Loading/Unloading Valves, Pressure Transducers, Digital Pressure Gauges with relays, and all filters; inspection, testing, and nitrogen topping of bladder-type accumulators; replacement of all seals and gaskets; Chemical and mechanical cleaning and flushing of all connecting pipelines including first fill of oil. Reassembly and functional testing. |
| 26 | Cooling Water System: Cleaning and Flushing Chemical and mechanical cleaning and flushing of all cooling water connecting pipelines. Dismantling, de-scaling, and mechanical cleaning of plate-type heat exchangers. Inspection and functional testing of existing globe valves. |
| 27 | Dewatering Pumps : Refurbishment of 3 phase, 7.50 HP submersible, dewatering pumps |
| 28 | Complete Restoration of existing automation panel of automated dewatering system |
| 29 | Providing and installation of HMI of governor panel for unit II |
| 30 | Providing and installation of CPU of governor panel of unit-I |
| 31 | 03 NOS. SYNCHRONOUS GENERATORS AND ROTARY EXCITERS. Phase 1: Comprehensive Cleaning Procedure:Primary Dry Cleaning (vacuum, compressed air, brushing, wipe- down) To Use industrial vacuum cleaners (with non-metallic attachments) to remove bulk loose dust and debris from stator core, rotor poles, and windings. Use dry, oil-free compressed air (pressure regulated) to blow out remaining particulates from ventilation ducts and hard-to-reach areas. Use soft, non-abrasive brushes (fiberglass/nylon) for loosening stubborn deposits. Final wipe-down with lint-free cloths. |
| 32 | Secondary Solvent Cleaning (IPA application, external detergent cleaning) using industrial-grade Isopropyl Alcohol (IPA) or non- corrosive electrical cleaning solvent using lint-free cloths or swabs to dissolve and remove oil, grease, and carbon deposits from winding surfaces, connections, and insulation. For external surfaces, use a mild, non-ionic detergent solution, followed by rinsing with de-ionized water and thorough drying. |
| 33 | Phase 2: Restoration, Curing, & Final ValidationAdvanced Cleaning – Dry Ice Blasting: Blasting on stator core, rotor spider, and other structural components to remove deeply embedded contamination, old paint, and carbonized deposits without damaging the base material or creating moisture. This process shall not be used directly on winding insulation or sealed surfaces without specific approval |
| 34 | Controlled Drying (monitored temp & humidity cycle) . After wet cleaning, subject the stator and rotor windings to a monitored drying cycle. Use space heaters, temperature-controlled ovens, or low-voltage current injection method. Monitor and record temperature (not exceeding manufacturer's limits, typically 80- 90°C) and humidity until windings are thoroughly dry as per IEC 60034-27-1 (steady insulation resistance for >4 hours). |
| 35 | Initial Electrical Verification (IR & PI tests) Insulation Resistance (IR) Test: Measure Polarization Index (PI) and Dielectric Absorption Ratio (DAR) of stator and rotor windings at a test voltage as per IEEE 43. Record IR values at 1 minute and 10 minutes. |
| 36 | Diagnostic High-Potential Testing (PD, HV, Tan-Delta, if PI ≥ 2.0) (Based on Initial Findings): If PI < 2.0 or as specified, a detailed investigation into moisture or contamination shall be conducted before proceeding. |
| 37 | Protective Re-Varnishing (application of insulating varnish)Apply a minimum of two (02) coats of high-quality, Class F or higher, solvent-based insulating varnish (e.g., epoxy or polyester) to the stator and rotor windings. Application shall be by dipping, spraying, or trickling method to ensure complete penetration and coverage.Follow manufacturer's instructions for mixing, viscosity, and application |
| 38 | Final Curing & Acceptance Test. Bake the varnished windings as per the varnish manufacturer’s prescribed temperature-time cycle in a controlled oven or using a current injection method. Final Acceptance Tests: Final IR & PI Test (IEC 60034-27-3). Winding Resistance Measurement (IEC 60034-1). Impedance Test on rotor windings. Surge Comparison Test (if equipment available) to detect turn-to-turn faults. Core Loop Test (EL-CID or RSO) as per IEC 60034-27-1 to ensure no core insulation damage was caused during cleaning. |
| 39 | Mandatory Electrical Testing and Commissioning of GeneratorsThe successful bidder shall carry out the following electrical tests on all three generator units, strictly in accordance with relevant IS/IEC standards as referred and as per directions of the Engineer-in-Charge. All necessary instruments, manpower, and consumables shall be arranged by the contractor at their own cost:1. Continuity and insulation resistance (IR) test of stator and rotor windings.2. Polarization Index (PI) test.3. High Potential (Hi-Pot) insulation withstand test.4. Complete winding surge test.5. Turn-to-turn insulation test.6. DC winding resistance measurement of stator and rotor windings.7. Pole drop test on rotor winding.8. Load test of generator.9. Digital ELCID test for stator core and rotor winding assessment.10. Temperature rise test/check-up for stator and rotor under operating conditions.11. Tan Delta test.All test results shall be duly recorded, documented, and submitted for approval. Any deficiencies observed during testing shall be rectified by the contractor without any additional cost. The work shall be considered complete only after satisfactory completion and acceptance of all tests. |
| 40 | Recommissioning of all the synchronous generators on 80 % of the rated capacity without any technical glitches like vibration beyond permissible limits, Axial thrust, uneven temperature rise in windings, Bearings etc. Please Enable Macros to View BoQ information |
