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PROJECT REPORT

ON

RIHAND STPP STAGE-II 2X500MW

MAIN PLANT TURNKEY PACKAGE

Prepared by:

SK Agarwal Dated: Dy General Manager 20.12.2006 BHEL Rihand STPP

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RIHAND STPP

STAGE-II

2X500MW

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INDEX

SL NO

DESCRIPTION PAGE NO

1 ABOUT RIHAND SITE 4 2 PROJECT SCHEDULE 5 3 EQUIPEMENTS/ SYSTEMS – INSTALLED

FOR RIHAND - STAGE-II 6

4 CONTINGENCY ARRANGEMENTS DURING COMMISSIONING

14

5 BENCH MARKS AT RIHAND SITE 15 6 QUALITY IMPROVEMENTS 17 7 SITE IMPROVEMENTS 18 8 PARADIGM SHIFTS IN ERECTION PROCESS 21 9 INITIAL TEETHING PROBLEM 22

10 OTHER MINOR PROBLEMS FACED BY SITE 36 11 MAJOR PROBLEMS & FAILURES 45 12 SUGGESTIONS FOR BOWL MILL

IMPROVEMENTS 80

13 TRIAL RUN OPERATION 85 14 DELAY ANALYSIS 89 15 PG TEST CONDITIONS 99 16 TOOLS & PLANTS - MAJOR T&Ps DEPLOYED

BY BHEL 109

17 OFFICE, STORAGE & HOUSING 110 18 AGENCIES DEPLOYED FOR 2X500MW 111 19 MILESTONES DATES RIHAND UNIT#3 & 4 113 20 TONNAGE ACHIEVED IN BOILER MONTH

WISE 115

21 BOILER ERECTION STRATEGY 117 22 PHOTO GALLERY 142

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ABOUT RIHAND SITE: NTPC RIHAND STPP was conceived as a coal based super thermal power plant of 2000 MW capacity. Stage I of the project comprising of GEC UK make two units of 500MW each is under commercial operation. This project was executed by NEI, UK under bilateral aid from UK. The present expansion, stage II comprising of two units of 500MW was awarded to BHEL on 14.08.2001. Major scope of work comprising design, manufacturing, supply and erection & commissioning of Steam Generator, Steam turbine, Generator, Associated auxiliaries, Fire protection system, Hoisting equipments & elevators, Air conditioning & Ventilation system, EOT cranes, 400KV switch yard etc. Total contract value is US$ 347,996,566.00 and Rs 2,057,188,944.00. LOCATION: The site is located on the southern bank of Rihand reservoir near village Bijpur in District Sonebhadra of Uttar Pradesh and it touches the boundary of three states MP, Chattisgarh and Jharkhand. The site is situated south east of Singrauli STPP across the reservoir at a distance of about 12 Kms (Crow fly). Other power stations around the reservoir are NTPC Vindhyachal STPP at 35 Kms and UPVN Anpara TPS at 75 Kms from Rihand STPP by road. Nearest city is Varanasi and its airport is 260KM from Rihand site. As RIHAND is touching the borders of Naxal infested states, it is a NAXALITE PRONE AREA.

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PROJECT SCHEDULE:

- PROJECT ZERO DATE: 14.08.2001

- NTPC PLACED THE NOTIFICATION OF AWARD (NOA) ON 14.08.2001 WITH THE OPTION OF MPS-225 OR XRP-1003 MILL TO BE EXERCISED WITHIN ONE AND HALF MONTHS FROM THE DATE OF NOTIFICATION OF AWARD. BUT NTPC TOOK 9 MONTHS AND 19 DAYS TO CONVEY THE DECISION.

- NTPC CONVEYED FORMAL DECISION TO GO AHEAD

WITH XRP MILLS ON 03.06.2002.

- BHEL INITIATED ACTION ON BOILER ENGINEERING AND MANUFACTURING AFTER RECEIPT OF CONFIRMATION ON 03.06.2002 FROM NTPC.

- THE ORIGINAL L1 DATES MAINTAINED FOR THE

PURPOSE OF MONITORING AS 13.11.2004 & 13.05.2005 FOR SYNCHRONIZATION AND 13.02.2005 & 13.08.2005 FOR TRIAL RUN COMPLETION FOR UNIT # 3 & 4 RESPECTIVELY.

- AS NTPC DELAYED THE MILL DECISION, THE

CONTRACTUAL DATES REVISED FOR SYNCHRONOSATION AND TRIAL OPERATION COMPLETION AS 13.03.2005 & 13.06.2005 FOR UNIT#3 AND 13.08.2005 & 13.11.2005 FOR UNIT#4 RESPECTIVELY.

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EQUIPMENTS/ SYSTEMS – INSTALLED FOR RIHAND - STAGE-II

STEAM GENERATORS : Two combustion engineering design BHEL steam generators are of controlled circulation single reheat, balanced draft with fusion welded war wall panel units having a primary steam flow 1675 tonnes/hour, Super heater out let pressure is 179 kg/ sq-cm at a temp. of 540°C with an inlet feed water temp of 254°C . The reheat steam flow of 1394 TPH will be raised to an outlet temp. of 540 from inlet condition of 45.8 Kg/sqcm and 336°C . The furnace is having overall dimension width 19.177 meter and depth 15.797 meter and height 62 meter effective and the furnace walls are fusion welded panel are large in size to minimize erection weld at site. Each unit is having one steam drum and connected to that down take system are suspended. There are six down takes evenly spaced along the drum length connected to suction manifold & 3 submerged motor boiler water circulation pumps with two outlet each forms the circulation system. Super Heater, Reheater and Economizer : The super heater consist furnace roof tubes to the rear of the unit where it cools walls of rear pass. The steam from here enters into 3 loop pendent low temp. super-heater located above economizer., with spray facility at the out let before entering divisional panel and finally to super heater.

The Re-heater is one stage: located in between divisional panel and super heater exit panel. Furnace wall is having 88-wall blower and 32 Nos. of long retract for plates, re-heater & convective super heater heating surfaces. TURBO-GENERATOR: Two turbo generators of BHEL HARIDWAR Make (KWU Design) is tandem compounds 3 cylinder machine with single flow HPT & double

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flow IPT & LPT with 6 extractions inclusive of feed water heating and steam to feed pump drive turbine.

Each generator is water-cooled stator & hydrogen cooled rotor rated 588 KWA at 21KV with 0.85 power factor with short circuit ratio of 0.5. Generator is having alkaliser, end winding vibration monitor, partial discharge monitoring etc.

Excitation is direct shaft driven.

FUEL - COAL, HFO & LDO:

The primary fuel is Bitumen coal from SLC (LT) Amlori mines of NCL. Transportation of coal is through MGR system constructed for stage-I, with provision of doubling of track.

The coal handling plant (CHP) for stage-II is constructed by BHEL ISG Bangalore. With a separate railway siding to track hopper (RCC) receives coal from hopper & convey to crusher House with transfer points (six) through conveyor reaches the silo/bunker of mills with by pass facility for diverting the crushed coal excess of the requirement to coal storage area. The capacity of plant is 2200 TPH with 100% stand by, with 16 hours spread operation.

Stacked/re-claimer facility is also provided for feeding coal from coal yard to conveying the coal to steam generator.

HFO fuel oil storage is common for with stage-I & II constructed during stage-I. The pump house for forwarding is separate for stage –2 and common for both 3&4 units. BHEL (Agency – M/s Techno Fab Pvt Ltd) has constructed the LDO unloading facility for stage-II, required for the start-up of the boiler.

ELECTRICAL SYSTEM:

The electrical transmission from the plant is by 400 KV from Transformer (21 KV from Gen side). Each unit is having three single phase Transformers with an individual rating of 214MVA, 21/400 KV, cooled with off load tap changer.

AUXILIARY ELECTRICAL SYSTEMS:

The Aux. Electrical system for each unit is served with connected Unit Transformer of 21KV/11KV - 45MVA with 2 nos Unit Auxiliary Transformer 11KV/3.3KV – 16MVA. In addition to this, one no station transformer & station auxiliary transformer (start up) for each unit, having rating 80/40/40MVA-132/11/11KV & 16MVA – 11/3.3KV, are installed with interconnection facility. One no colony service

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transformer of rating 12.5MVA – 132/11KV is installed in 132KV switch yard. All these transformer are supplied by BHEL – Bhopal/ Jhansi. The LT supply arrangements are as under:

• Dry type service transformer 2000KVA-3.3KV/433V – 2 nos per unit.

• Dry type station service transformer 2000KVA-3.3KV/433V – 2 nos per unit.

• Oil filled fire water pump house service transformer 2000KVA – 3.3KV/433V – 2 nos.

• Oil filled fire water pump house service transformer 2000KVA – 3.3KV/433V – 2 nos.

• Oil filled off site service transformer 2000KVA – 3.3KV/433V – 2 nos.

• Oil filled ESP service transformer 1600KVA- 3.3KV/433V – 8 nos per unit.

The MD-BFP, ID, CW, PA, FD and CEP motors, rated above 1500KW are fed by 11KV. The mills, ECW, ACW, compressor & make-up/ raw water motors rated above 200 KW to 1500KW are fed by 3.3KV & up to 200 KW by 415V systems.

The each unit emergency is fed by 1200 KW DG set with one spare common DG set.

D.C System: (Supplied by M/s HBL Nife through BHEL) 220V – 2 Nos. with float a boost charger to supply DC emergency pumps, scanner air fan & some selected service for 30 minutes duration.

PLANT AUXILIARY SYSTEMS:

The regenerative feed water heating system design is conventional one. Six stages of feed water heating comprises of 3 LP heaters, Dearator, and two high pressure heater. The LP heater & HP heaters is tubed with SS tube material of SA688 TP 304 specification.

3x50 percent capacity condensate extraction pumps are driven by 11 KV motor. One 50% Boiler Feed pump is motor driven for start up purpose & other 2 x 50 % Boiler capacity are turbine driven feed pump. The feed pump turbine exhaust is connected to main turbine condenser.

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ASH HANDLING SYSTEM : (Supplied by M/s Burn & Standard)

Boiler bottom Ash extracted in wet form & disposed off in wet form. The fly ash is extracted in dry form from ESP to be taken to hopper for onward transportation to ash silo in dry form or slurred in wetting units for ultimate disposed in wet form to ash disposal area (ASH DYKE).

The bottom ash & fly ash slurry are led into common slurry sump for further disposal to ash disposal areas through pumps & piping work.

WATER SUPPLY & COOLING WATER SYSTEM:

Water supply for the plant is from the Rihand reservoirs and make up water is drawn from two locations - from stage-I CW pumping system water for DM water requirement and potable water system & make up water requirement for CW system is drawn from stage-I CW discharge channel, which also serves other miscellaneous requirements of ash handling/AC & ventilation etc.

M/s PAHARPUR supplied Re-circulating & Forced draft type cooling towers are installed for stage – II, unlike open channel for stage-I. 3x50% capacity clarified water pumps using discharge water drawn from clarified water storage tank, through bar screen & trash rack.

The total water requirement is 60,000 m³/hour. Five numbers of half capacity (two for each with a common standby) concrete volute vertical pit turbine type (30400 m³/hour) pumps of M/s KBL make with BHEL Bhopal make vertical motors are installed in CW pump house. Single M.S. pipe of 3600mm diameter pipe carries the water from the fore bay to plant & back to the fore bay through cooling towers. Aux. Cooling: For the auxiliary cooling water system, the water is drawn from CW inlet pipe before condenser & 3x50% capacity pump will take suction and discharge to the CW outlet at the CW out let pipe near condenser through 2x100% capacity & 3x50% capacity plate heat exchangers of boiler side cooling water & turbine side cooling water cooler respectively, removing the heat of closed water DM cooling water system of boiler common auxiliaries & turbine, generator auxiliaries.

The vacuum pump coolers are directly cooled by CW water.

The equipment cooling water is DM water closed with NaOH, is separate overhead tank and pumping arrangement with piping to different coolers & back to pump suction.

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2x100% capacity pumps are used for boiler side + compressor & 3x50% capacity pumps serves turbine side equipment cooling requirement. COMPRESSED AIR SYSTEM: (Supplied by M/s Atlas Copco through BHEL) The compressor air system is common for both the plants. 5 numbers of rotary screw type compressors - 3 for service air and 2 for instrument air serves the plant requirement with a provision for connection to stage-I. The plant and instrument air piping at the out let of the compressor is having facility for interconnection and the regenerative drier 2 nos is provided with all peripherals like tank etc. FIRE PROTECTION SYSTEM : (Supplied by M/s Wormald through BHEL) A comprehensive fire detection system like (infrared quratzoid bulb, linear heat sensing cable, photoelectric type heat sensors and protection system like high, medium velocity water spray, Hydrant water monitor, foam system inergene system, fire extinguisher to be actuated through sensors/manual actuation facility protects against fire. Other associated system like pumps, tanks, booster form part of the fire protection system. AIR CONDITIONING & VENTILATION SYSTEM: (Supplied by M/s ABB through BHEL) The system comprises of central chilled water type of 2x50 vapor absorption machine (both working) and 2x50% screw chiller normal standby mode for main plant control room, UPS & SWAS room, ESP- VFD control room of unit 3 &4 air-conditioning requirement. The subsystems associated with this are cooling water system including cooling towers & make up water system, chilled water system with make up provision form expansion tank, air handling units at 11 different locations with fans and air flow control devise. All the controls and operation are PLC based with hook up with main control room PLC. Service building air conditioning requirement is met with two screw chillers with all the peripherals as enumerated for the main plant. BALANCE OF PLANT - Split air condition units of different capacity serve balance of plant control room air conditioning requirement.

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THE VENTILATION SYSTEM is separate for each unit. The B-C bay ventilation unit located at 24 meter elevation & A row at 8.5 meter elevation serves the TG hall, MCC, switch gear room, etc. Other offside plant and other buildings, which are not connected with main ventilation system, are provided with ventilation fans of adequate numbers. AUXILIARY HEATING: From the stage-I, steam is drawn for supply of steam for unit start up, for serves like fuel oil heating/steam tracing, steam coil air pre heater, vapour absorption machine, flue gas conditioning skid etc. WATER CONDITION & QUALITY CONTROL: The conditioning of cycle make up water is common for both units. All other water treatment, conditioning & monitoring is separate for each unit. The DM plant of 100 m³/hour is of six-bed concept, supplied by M/s Ion Exchange. The steam generator-turbine-condenser cycle is controlled in a fashion normal for a drum type of boiler. These include volatile chemicals for feed water corrosion reduction such as ammonia & hydrazine and utilize the coordinated phosphate method of control for boiler water. The condensate polishing re-generation (CPU) is common for both units supplied by M/s DRIPLEX through BHEL. A powdered-resin condensate polishing system capable of handling full load condensate with its two filters polished with by pass facility. CW basin is provided with shock chlorination for algae control. The equipment cooling water system will be closed with sodium hydroxide. A centralized water quality monitoring system receive sample from through out the plant as well as grab sample analysis facility ensures the plant water regime.

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CONTROL & PLANT MONITORING: Microprocessor controller EDN MAX DNA boiler turbine controls & protection is DDCMIS. The coordinated system is providing control unit generation on a feed forward basis. The controls provide for automatic operation either the constant pressure or sliding pressure mode. Also included in the system is automatic control of super heater by passing the steam in HP/LP by-pass system for matching the steam temperature with the turbine metal temperature during hot start and initial start up etc. The system is very extensive and includes:

• Generation of operating information • Generation of historical records • Control of electrical system • Large video screens • Man machine interface • Alarm system & analysis • Digital display analogue trends & dynamic graphics • Vibration monitoring system.

All the balance of plant controls are PLC based supplied by GE-FANUC with a battery back up of HBL-Nife. PUBLIC ADDRESS SYSTEM: (Supplied by M/s Bytes Communication through BHEL) A distributed amplifier based public address system is provided for communication within the plant through hand set stations distributed throughout the plant to ensure proper communication.

ENVIRONMENTAL ASPECTS:

Water Pollution: Since the CW system is re-circulation type there is no significant thermal pollution. The CW blow down water used for coal dust suppression & extraction system & service water system is of re-circulation type. Ash water re-circulation system is provided with adequate treatment facilities. Oil water separator is provided to separate the oil and the water from the bottom would be recycled.

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All the effluent (from DM plant, CPU regeneration plant, plant drainage, oil water separator is treated at Effluent treatment plant (supplied by M/s DRIPLEX through BHEL) before discharging to Rihand reservoir. Oil & Chemicals: The fuel oil, lubricant and chemicals are controlled by containment. Chemicals like Hydrochloric acid, sodium hydroxide, sulphur is stored in vessels with lined concrete containment. Air Pollution:

1. In an effort, to minimize the environment impact of NTPC Rihand stage-II, High efficiency ESP is provided with Flue gas conditioning system (Installed first time in INDIA by M/s Bahmann India Ltd under technical collaboration with M/s Wahlco USA through BHEL) with Sulphur tri oxide injection to reduce the resistibility of ash & increase collection at the plate and SOX reduction.

2. Chimney height is 275 meter will disperse hot flue gas to atmosphere with stack emission monitor.

Solid water waste management : Fly ash & bottom ash - It is disposed in a separate ash dyke (Constructed by M/s HSCL) impoundments to be reclaimed through tree plantation after abandonment. Also fly ash collected as dry is used for making bricks & filling of earth in the plant, township and nearby areas. The mill rejects from each pulverizer is sluiced individually to the bunker (pneumatic transportation) and periodically collected and hauled to the allotted location. The Mill Reject System is installed by M/s Macabber Bekay through BHEL. NOX Control: The tangential fuel firing system, which promote large amount of essentially horizontal re-circulation of gases in the furnace, this completed with slow mixing of fuel air, provides for combustion, that is inherently low in NOX reduction. The over fire air design and two stage air admission reduce the NOX production.

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CONTINGENCY ARRANGEMENT DURING COMMISSIONING

INITIAL DM WATER & AIR REQUIREMENT

Temporary line of 200 Nb pipe with valves about 200 meters was laid from stage I at a location in between unit 2&3 for HYDRO TEST of boiler#3 initially and kept in use till the completion of both units acid cleaning.

COMPRESSOR:

The compressor cooling water requirement for initial trial run of the compressor was met by temporary open cooling water with the use of DM water teed off from the line laid for boiler hydro test purpose. This arrangement was retained till regular ECW system was made ready.

MAIN CONTROL ROOM AC PLANT:

AC plant make up water was not ready due to the pipe trestle erection problem, as the same could not be erected by virtue of lay out and pending building completion clearance.

The cooling water and chilled water initial filling and make up requirement was met by laying a 3 inch line from the unit-2 fire hydrant system and the same was maintained for a long time as the trestle erection clearance was given very late.

FIRE FIGHTING SYSTEM:

The stand-alone fire fighting system for stage two was not ready during the initial commissioning of start up transformer and unit auxiliary transformers.

From the existing stage – I, a tapping was taken and laid temporary 4 inch line and connected to the transformer emulsi fire system line and subsequently connected to stage II mains.

NEUTRALIZATION OF ACID:

The neutralization of spent acid was piped to the stage I , DM effluent tank ( about 1.5 km away ) for treatment with NaOH & final discharge to the regular drainage after ensuring the discharge water is fit for use so that water contamination is minimized. Based on unit#3 experience, NaOH was procured in tankers & unloaded in Stage-I DM plant tanks to send NaOH through pipe lines connected to effluent tank, unlike unloading by the drum. The spilled acid on the floor / equipment is neutralized with lime and washed with water.

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BENCH MARKS AT RIHAND SITE

THE DRUM LIFTING OF UNIT#3 ACHIEVED ON 29.03.2003 i.e.

WITHIN 9 MONTHS AND 26 DAYS OF THE CONFIRMATION OF ORDER, WHICH IS SHORTEST TIME TAKEN SO FAR FROM THE DATE OF CONFIRMATION OF ORDER TO DRUM LIFTING.

THE DRUM LIFTING OF UNIT#4 ACHIEVED ON 11.07.2003 WITHIN 3 MONTHS & 13 DAYS AFTER FIRST DRUM LIFTING, 94 DAYS IN ADVANCE w.r.t. L2 SCHEDULE.

SITE HAS ACHIEVED MORE THAN 3000MT PHYSICAL ERECTION IN BOILER PACKAGE 2X500MW CONSECUTIVELY FOR THREE MONTHS. (NOV’03 – 3714MT, DEC’03 – 3412MT & JAN’04 – 3174MT).

HIGHEST TONNAGE IN 500MW BOILER IN A SINGLE MONTH –2071 MT (NOV’03)

HIGHEST HP JOINTS (EQ.) IN 500MW BOILER IN A SINGLE MONTH – 6310 NOS (NOV’03).

HIGHEST TONNAGE IN 2X500MW BOILER IN A SINGLE MONTH – 3714MT (NOV’03)

HIGHEST TONNAGE IN ESP#4 500MW IN A SINGLE MONTH – 874MT (DEC 03).

THE ENTIRE CONDENSER TUBE INSERTION (24398 NOS) COMPLETED IN A RECORD TIME OF 26 DAYS AND ALSO HIGHEST 3350 NOS TUBE INSERTION IN A SINGLE DAY ACHIEVED ON 27.12.2003.

BOILER # 3 & 4 HYDRAULIC TEST OF DRAINABLE PORTION COMPLETED ON 30.01.2004 AND 19.06.2004 – •IN A FIRST FILL ITSELF i.e.IN A SINGLE FILL OF BOILER. •PRESSURE DROP OF MERE 2 KG/CM2 FOR A PERIOD OF HALF AN HOUR (AGAINST PERMITTED NORMS OF 15 KG/CM2 ) AT THE FULL TEST PRESSURE OF 310.50 KG/CM2

•TEST SUCCESSFULLY COMPLETED IN LESS THAN 24 HRS.

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BEST SAFETY AWARD FOR BHEL SITE BY NTPC FOR THE YEAR 2003-04.

BOTH 500MW UNITS GENERATED AT A PLF MORE THAN 90% DURING THE FIRST YEAR OF OPERATION. THE UNITS WERE STABILISED IN A MINIMUM TIME.

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QUALITY IMPROVEMENTS

ARRANGEMENT OF LADDERS WITH BOILER COLUMNS TO FACILITATE SMOOTH CLIMBING AND TO AVOID WELDINGS/ GAS CUTTING/ GRINDING ETC (ANGLES/ CHANNELS ETC) ON COLUMNS. CABLE TRAYS FIXING BY CLAMPS/ FASTENERS AS AGAINST WELDING. FIXING ARRANGEMENT OF FLOOR GRILLS BY SELF DRILLING SCREWS INSTEAD OF STUD WELDING ON STRUCTURE.

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SITE IMPROVEMENTS

• SITE MOBILISATION: DEPLOYMENT OF SELF CONTAINED PORTABLE BUNK OFFICES FOR INSTANT MOBILISATION OF SITE ACTIVITIES. •PRE ASSEMBLY, WELDING AND NDT WORKS OF MBLs OF BOILER CARRIED OUT AT PRE FABRICATION YARD (GROUND LEVEL) INSTEAD OF WORKING AT HIGH ELEVATIONS, RESULTING IN FASTER WORK, IMPROVED QUALITY AND SAFETY. •COLUMNS & CASING WALLS OF ESP PREASSEMBLED AT GROUND FLOOR AND THEN ERECTED, THUS REDUCING THE NO OF LIFTS FROM EIGHT TO ONE ONLY. •ESP HOPPERS: AS PER PRACTISE, HOPPERS WALLS RECEIVED IN 3 PARTS, ARE ASSEMBLED AT GROUND & ERECTED IN 4 LIFTS. AT RIHAND PROJECT, COMPLETE HOPPER ASSEMBLED AT GROUND AND ERECTED IN ONE LIFT. •RADIANT ROOF, LOOSE TUBES WERE SUPPLIED. THESE TUBES WERE WELDED IN THE FORM OF PANEL AT GROUND AND THEN LIFTED. THE ROOF OF SECOND PASS WAS ALSO ASSEMBLED AT GROUND. •ECONOMIZER COILS AND LTSH COILS WERE ERECTED BY USING SLIDING PULLEY ARRANGEMENT, WHICH REDUCED THE CHANGE OVER TIME FROM ONE COIL TO ANOTHER. •UNION HEAD AND JOURNAL OF BOWL MILL WERE PREASSEMBLED IN YARD, TRANSPORTED TO SITE AND THEN ERECTED. THIS HAS REDUCED THE NUMBER OF LIFTS FROM 60 TO 30. •DIVERTER AND FLAP DAMPERS WERE PREASSEMBLED AND THEN ERECTED. IN THIS WAY, NO OF LIFTS WERE REDUCED TO THREE. •MILL PROTECTION ARRANGEMENT: MADE FOR MILL BASE AS THESE WERE ERECTED BEFORE FEEDER FLOOR AVAILABILTY. TONNAGE ACHIEVED 750MT FOR EACH UNIT.

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•EFFECTIVE UTILISATION OF CRANES: 3 NOS CRANES ( 1 NO FMC LS718 – 325MT, 2 NOS KH700/ LS248 – 150MT) ARE DEPLOYED AT SITE AGAINST CONTRACTUAL COMMITMENTS OF 5 NOS (2 NOS – 325MT, 2 NOS – 150MT & 1 NO – 100MT). NET SAVING DURING THE YEAR 2003-04 IS RS 170.00 LAKHS. •STORAGE AREA IDENTIFIED AS LOCATIONS A1 TO A11 (11 ZONES); MATERIALS STORED AND LOCATION RECORDED AGAINST EACH ITEM, ENABLED RETRIEVAL OF MATERIALS FOR ERECTION WITHOUT ANY DELAY. •RACKS FOR LOOSE ITEMS: ALL WELDED ANGLE RACKS MATERIALS RECEIVED FROM OTHER SITE IN CUT PIECES, WERE MODIFIED AS DISMANTLING TYPE BOLTED ANGLE RACKS. •HAND OPERATED OVER HEAD CRANES ARE PROVIDED IN THE 4 NOS STORAGE SHEDS FOR SAFE LOADING/ UNLOADING OF MATERIALS. EFFECTIVE UTILIZATION OF STORAGE SPACE. •OLD T&P, LIGHTING FIXTURES AND OTHER ELECTRICAL ITEMS OVERHAULED AND UTILISED AT SITE. •DISMANTLED SHEDS RECEIVED FROM OTHER SITE USED FOR CONSTRUCTION OF SEMI CLOSED STORAGE SHEDS. •SOMS: FIRST TIME IN BHEL ON LINE SITE OPERATION MANAGEMENT SYSTEM IMPLEMENTED – TO HAVE AN INSTANT AND ON LINE INFORMATION TO ALL CONCERNED (BHEL/ NTPC/ ERECTION AGENCY) REGARDING MATERIALS & DOCUMENT STATUS (RIGHT FROM DESPATCH – RECEIPT – STOCK – ISSUE), DEVIATION REPORTS, PERFORMANCE MONITORING OF WELDERS/ PROGRESS OF WELD JOINTS/ NDT. - INTEGRATED WITH MU AND REGION HQ. - ACCESS TO ALL PLACES THROUGH INTERNET. - IMPROVED QUALITY OF INFORMATION. - PROMOTING PAPERLESS OFFICE. - REDUCED MANPOWER. •FIRST TIME IN BHEL ON LINE WEB BASED FINANCIAL APPLICATION IMPLEMENTED AT SITE. •CONSERVATION OF ENERGY: TIMERS ARE PROVIDED ON ALL LIGHTNG MASTS AND POLES FOR AUTOMATIC SWITCHING ON/OFF

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FOR CONSERVATION OF ELECTRICITY AND REDUCTION IN MANPOWER.

2ND PASS ROOF ASSEMBLED AT

GROUND UNION HEAD & JOURNAL IN

ASSEMBLED CONDITION

MILL BASE PROTECTION ARRANGEMENT MADE AS FEEDER FLOOR WAS DELAYED BY CIVIL AGENCIES

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PARADIGM SHIFT IN ERECTION PROCESS

•100% AVAILABILITY OF CONSTRUCTION POWER: 14 Sub-stations of 500MVA capacity each and two different sources for 11KV & 5.5 KM ring-main provided. •PRE – ASSEMBLY YARD: WBM levelled and all weather pre - assembly yard of size 20,000 sq mtr. Adequate illumination to facilitate ROUND THE CLOCK PRE- ASSEMBLY WORKS. •SITE OPERATIONS MANAGEMENT SYSTEM: First time in BHEL on line SOMS installed at Rihand for Materials (integrating despatch from unit – receipt – verification/MDRs – issue – billing), Documentation, Site deviation reports, Welders performance monitoring, MIRs, etc. •ERECTION STRATEGY: A comprehensive document finalised in consensus of all concerned. This document was generated to identify Materials sequence, Erection practices, T&P Mobilisation (Type/range/schedule), Location of Cranes, Civil Foundation to be put under hold for movement of cranes, approach road to Boiler/ESP, arrangement for feeding of materials etc.

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INITIAL TEETHING TROUBLES:

DESCRIPTION PAGE NO

CEP RECIRCULATION VALVE YOKE BREAKING 23

CEP RECIRCULATION VALVE JAMMING 23

REPEATED FEED CONTROL – VALVE OPERATION PROBLEM 23

ESP HOPPERS – PANEL TYPE HEATERS – ASH EVACUATION 24

CLINKERING PROBLEM IN BOILER 24

SEAL AIR FAN 25

ASH LEVEL INDICATOR 25

MCC CONTACTS PROBLEM 26

WALL BLOWER OPEARTION 26

ESP – LT MCC 26

MAIN TURBINE VACUUM PUMPS 27

HT SWITCH GEAR PROBLEM 27

ATLAS COPCO MAKE COMPRESSORS – BLADE FAILURES. 28

SELF CLEANING STRAINER OF ACW SYSTEM 28

FD FAN –API 26/16 (RTD PROBLEM) 28

BOILER TUBE METAL TEMPERATURE (GAS SIDE) MEASUREMENT - ACROMET THERMOCOUPLE

29

HFO OIL COOLER 31

PA/ FD FAN LINKAGE PROBLEM 31

AIR PRE-HEATER (SAPH/ PAPH) ROTOR STOPPAGE ALARM 31

AIR PRE-HEATER OVER-RUN CLUTCH FAILURE 32

SECONDARY APH – HOT END SOOT BLOWER 32

MILL SIDE PROBLEMS 33

ECW SYSTEM 33

ACW SYSTEM 34

BOOSTER PUMP MECHANICAL SEAL FAILURE 34

MD BFP – C&I PROBLEMS 34

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CEP RECIRCULATION VALVE YOKE BREAKING: While starting the pump, sudden rush of water flow in the recirculation line was causing jerk & high vibrations in the recirculation pipe line & main line. The analysis revealed that by virtue of recirculation line tap of routing the recirculation line & the CEP discharge line up to NRV was getting drained to the level of condenser level by creating air column in the discharge line.

When the pump is started, the sudden rush of water causes the line to vibrate heavily and damaging the yoke. Additional supporting in the recirculation line is no help.

With PEM concurrence, one more NRV was introduced immediately after the pump in the discharge line to have always a water cushion & problem got eliminated.

CEP RECIRCULATION VALVE JAMMING: The CEP recirculation valves are cage & plug type valves with close tolerance. Even small contamination is sufficient to make the valve movement sticky. With the plug matching clearance was established, and valve operation became smooth.

REPEATED FEED CONTROL: VALVE OPERATION PROBLEMS: Feed Control Valve model No. VSC 10” XCU500 - Disconnection of stem & plug. This problem encountered in both the units, during initial operation.

• The nature of failure is called taper pin connecting stem & plug coming out halfway from location & obstructing the valve operation.

• The taper pin totally coming out and end the stem threading connection to the plug, getting un-served & stem become independent.

• From the failure, with higher across the valve during start up & initial commissioning operation, pin tends to come out halfway or fully.

We recommended the vendor, to make the connection better and free from trouble by seal welding the stem & plug on the thread stems and spot welding of taper pin after full insertion.

With the above, the valve problem was eliminated.

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ESP HOPPERS PANEL TYPE HEATERS: ASH EVACUATION PROBLEM: During coal firing, ash evacuation problem was experienced & ash was getting accumulated in the hoppers and manually removed by dumping at the ESP floor itself. It was inspected that ESP hopper heaters were not maintaining the hopper temperature at 120ºC with thermostat setting at 120ºC and hence ash is not freely flowing to de-ashing pipes. BHEL Ranipet & site, reviewed the installation of thermostat fixing. The panel heater vendor’s drawing calls for batting of installation with channel welded around hopper, but BHEL Trichy drawing calls for air gap. Due to this air gap, cross air current existed and hence the hopper temperature was not maintained. The thermostat installation was not as per vendor drawing and also Ash handling agency M/s Burn Standard, have not installed the mouthpiece. The installation application was modified & M/s Burn Standard also installed the mouthpiece in the entire hoppers with the above work. Initially there was considerable improvement; later on problem was fully resolved. Initially the hoppers before ESP were not connected to Ash evacuation system causing the ESP over burden. Later on, during shut down ash handling agency connected the hoppers. In Unit-4, the modifications were incorporated in the beginning itself. CLINKERING PROBLEM IN BOILER: Due to huge build up of clinkering with certain type of coal, Unit#3 load has to be reduced & twice has to be stopped for clearing the same. The matter was referred to BHEL/ Trichy and NTPC/OS group. BHEL has suggested removal of shield plate & deflector plate in the coal nozzles. NTPC agreed for the removal of only deflector plates. The same was implemented in Boiler#4 before coal firing and after seeing the performance of Unit#4, deflector plates of unit#3 was also removed during shut down. The clinkering problem is considerably reduced.

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SEAL AIR FAN: The seal air fan for milling system is over hung design with two different bearings placed on single bearing pedestal. The bearings are sump oil lubricated and the sump holding capacity is limited. The fan intake suction from P.A. cold duct & the fan shaft seal is labyrinth type with asbestos cut sheet. Both the seal air fans of unit#3 were damaged during the initial operation itself. We have to replace the bearings, its housings, distance tube & shaft. The air past fan shaft seal is pressurizing the nearest bearing housing & expelling oil out, causing starvation & failure. Also the contamination of oil is another reason for bearing failure. In consultation with BHEL Ranipet, a deflector shield installed on shaft between fan side bearing housing so that high-pressure air leakage past seal is diverted & does not enter the fan bearing.

With this arrangement the fan reliability was improved.

1. Grease Lubricated type is best suited for this dust laden atmosphere.

2. The leveling of both bearing housing on X & Y axis over pedestal is difficult for erectors.

3. For vulnerable service fans, bearing temp indication at UCB with trip is to be implemented.

ASH LEVEL INDICATOR: The performance is Ash Level indicator is not satisfactory. False level indication trips the field & some time accumulation of ash damages hammer. Also the hopper ash empty time could not be gauged properly & for sequencing empty. The system is having highly maintenance problem & calibration gets disturbed often, requires continuous maintenance. A better-proven level indication system shall be tried.

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MCC CONTACTS PROBLEMS: The Switch Gear supplied was not giving reliable electrical contacts resulting in interruption & manual adjustment of breaker module for establishing contact. The matter was taken up vendor & they have changed the system with better type arrangements & the problem of soot blower operation interruption is very much minimized. WALL BLOWER OPERATION: Wall blower lance motor getting over loaded when the puppet valve begins to open. Three types of motors are supplied to this project namely Bharat Bijlee, Kirloskar & Crompton Greaves. The wall blower operation is designed for 30 Kg/Cm2 steam pressure at soot blowing header pressure. But during commissioning of blowers we noticed that all the motors are not operating with 30 Kg/Cm2 pressure, but these are operating at 20 to 25 Kg/Cm2. Hence the soot blower header pressure control is adjusted to 25 Kg/Cm2. The analysis reveals that the motors rating is just sufficient & any additional mechanical resistance in the blower, resulting in tripping of the traverse motor on lower pressing the puppet valve. All the blowers are being separated at 25 Kg/Cm2. At present 35 Kg/Cm2 steam pressure operation needs demonstration. Trichy valves division is supplying higher rating motors. ESP – LT MCC:

1. Module MCC - flash over. 2. Breaker Contact – problem 3. Bus dropper connection loosen & subsequent melting of Bus

dropper. Control & Schematic, Hyderabad representative was called for resolving the problem.

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VACUUM PUMP: M/s. Nash-Eland 6M bolt gearing Sl. No. 750 3640 0004 (3A) The pump 3A & 3B were commissioned on 23/11/05 with an arrangement of one stand by & other running and weekly change over of pump. On 12/01/06 when unit#3 was operating on full load with the condenser vacuum pump 3B of -0.92 Kg/Cm2, the standby pump stared on auto due to malfunctioning of vacuum switch. The operating current was 300 amps against a normal current of 175 to 180 amps and rated current of 240 amps. The pump was stopped after attending the vacuum switch problem for investigating the reason for higher current and pump was opened:

- 5 nos out of total 8 nos of stud bolts (3 nos at drive end & 2 nos at non drive end), holding intercepting valve & valve plate found in shear condition & the nuts of the remaining were found loosed.

- The valve plates (Teflon) on both DE & NDE found in damaged condition. & interception plate has fallen from its location.

- Dent marks found on the port plate of drive end. - Intercepting plates at both DE & NDE got dislocated from their

position and fallen down, due to shearing of stud bolts. The reason for failure was not established. It was suspected that material of stud bolts was defective. The damaged parts of pump were replaced with the mandatory spares and operation of pump found satisfactory. HT SWITCHGEAR PROBLEM: In HT switch gear following problems were faced.

• Racking in/out problem – due to mis-alignment. • Sulfuration of power contacts – cleaning was done. • Bus bar chamber sealing. • Breaker auxiliary limit switch line breaking frequency. • Spring charger Limit Switch falling regularly.

Bhopal representative has attended the above problems and supplied spare Limit Switches for replacement.

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ATLAS COPCO MAKE COMPRESSOR: COMPARTMENT COOLING FAN FAILURE: In all the compressor compartment, the cooling fan had failed. The blades were initially aluminium design. The supplier M/s. Atlas copco changed the impeller blades with steel material. With this replacement, no compartment fan failure is noticed. Compressor LP element failed in one of the compressor after 4300 running hours. The LP element was replaced with mandatory spares. The analysis revealed oil spray nozzle securing fasteners was found loose causing inadequate oil supply to the bearing of LP element. SELF CLEANING STRAINER OF ACW SYSTEM : In both units, self cleaning strainer installed in the ACW system after the pump discharge, 3 Nos. of the rotating unit got jammed. The inspection revealed that the drive unit supporting system at the location of bearing (lubron) is tight with rotating unit. All the bearings were removed from the location and the required running clearance (1mm) was established by matching the bearing by the supplier. With this rectification the equipment was put in service. FD FAN –API 26/16 (RTD PROBLEM): The RTD’s for bearing temp measurement assembly head was fouling with bullet inside ribs. Hence the RTDs are to be bend by more than 90 degree to clear the fouling.

The instruments fittings for the mounting of bearing temperature gauges and RTDs on the bearing housing were not matching with corresponding receiving portion in the bearing housing necessitating local arrangement.

The vibrations pick up, RTDs, and temperature gauges are not easily accessible as the bullet portion of the bearing is integral part of housing. SUGGESTIONS:

To avoid bending of the RTDs, pencil type RTD with long leads and fixing arrangement in the bearing housing will resolve the problem.

While ordering the RTD and Temperature gauges, fittings shall match to the bearing housing.

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For quick access and inspection of vibration pick – up and temp measuring instruments in the bearing, windows in the bullet shall be given , other wise the top half of the housing needs to be opened. BOILER TUBE METAL TEMPERATURE (GAS SIDE) MEASUREMENT ACROMET THERMOCOUPLE: In NTPC Project, in addition to boiler tube metal temperature measurement in the pent house area, gas side metal temperature measurement also is given as part of the contract. The Acromet thermocouple is used for measurement of gas side metal temperature of super heater tubes to pre-warn the operator if the temperature exceeds the limit given by the designer, the operator has to take corrective action for containing the temperature by any one of the following or combination of all: 1- Soot blowing 2- Air regime adjustment 3- Mill combination changes In Rihand, 14 Nos. of acromet thermocouple measurement is envisaged in platen super heater and divisional panel super heater element. Accordingly BHEL Trichy has supplied the thermocouples loose and to be inserted after the erection of the coils. The particular tube will have a protection tube with a 3mm dia wire inserted at works which is to be removed at the time of inserting the thermocouple. The method of placing the thermocouple in the gas side is that the thermocouple will go inside the button welded on the metal tube with a through hole mid way and other end is brought out of the pent house and wired to control room indication. With the above method of installation, the measurement of metal temperature was not exact. NTPC informed that method of installation was different for Simhadari units for the same measurement of thermocouple configuration and NTPC after lot of discussion with BHEL Trichy & thermocouple supplier agreed for the following:

• Thermocouple will have steel stud extension for 5mm at the measuring end and all the thermocouple were modified at vendor works.

• Procedure for thermocouple installation to be followed

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1. Cleaning of the tube at the location where the thermocouple stud to be welded.

2. After cleaning grind the surface by 3mm below the button already welded.

3. Insert the thermocouple so that the tip is out by 3mm from the button edge.

4. Weld the tip with tube. 5. Check the healthiness of thermocouple.

For Unit-3 and Unit-4 the installation were completed with the above arrangement and method. The measurement was found satisfactory. The space between roof top and the junction header is very less for working. The filling wire installed at factory in the protective tube gets stuck and removal is very difficult at site and some times it breaks while pulling the same.

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HFO OIL COOLER : The oil outlet temperature of HFO oil cooler was maintaining higher temp. & hence the oil tank oil temp. was going high & one pump got seized due to higher oil temp. at pump suction.

• The cooler intervals (water side shell nuts were removed) • The cooling water connections, which were from bottom of the

header, shifted to side so that mud do not enter the cooler. • Cooling water pipe line’s size was increased from 1 inch to 2 inch

& the problem is contained. PA/FD FAN LINKAGE PROBLEM : The fan loading of FD & PA Fan (axial blade pitch control type) the linkage to Electrical drive servomotor is Z connection.

The actuator location is very close to the fan casing and with the heavy acoustic insulation; part of the actuator was going inside insulation making the electrical connection limit adjustment difficult. In fact, insulation thickness was reduced in the area for facilitation of electrical connection, limit switches adjustment.

With Z connection, linearity could not be achieved between right/left fan, and for the same position, the load current was different & blade angle was different. The above discrepancy caused operation problem & auto control was difficult.

To eliminate the above problem, the actuator was moved away so that it is clear from the acoustic insulation & sheeting, by providing new foundation for actuator, and also to provide parallel movement of linkage.

Also the blade servo motor linking shaft was extended by a sleeve on the original shaft.

The linkage connection was made with the above modification, the operation/ control problem resolved.

AIR PREHEATER (SAPH/ PAPH) ROTOR STOPPAGE ALARM

In the regenerative air heaters, rotor stoppage alarm unit monitors the rotation.

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This unit consists of stationary proximity magnetic switch and electrical connection with timing device, which makes & breaks when flaps (3 Nos.) passes over it, which is mounted on rotor shaft above the support-bearing block.

The supplied arrangement is so filmsy that it gets disturbed & no sensing takes place or damages the proximity switch, the system hardly works.

The rotating element should be steady. The place available for clamping arrangement is very less and drg. line maintenance is very difficult. Site fabricated sturdy arrangement with sufficient mass at the end to cut magnetic flux when it crosses the magnetic switch. With this arrangement the system works satisfactorily. AIR HEATER OVER RUN CLUTCH FAILURE:

In SAPH application (once in unit#3) & in PAPH application (once in unit#4), over run clutch has failed. When BHEL Ranipet was contacted, we came to know that all the three sides’ isolation is a contractual requirement & hence they have given over run clutch in the drive side, though it could have been eliminated. The over run clutch was replaced from the spares. BHEL Ranipet, agrees for rigid half coupling in place of ORC & given sketches. SECONDARY APH – HOT END SOOT BLOWER: In both the units, hot end soot blowers nozzles fallen down in spite of locking nozzles adopter with lance pipe by tack welding. Also the twisting of elbow was noticed. During shut downs, it becomes routine to re-fix the dismantled adopter with nozzles to the lance pipe. The possible reasons analyzed at site & communicated to BHEL Ranipet as below:

• The wall thickness of the adaptor body is very less - In SAPH 3A, the thickness near the broken body was less than 2mm.

• The less tube wall thickness of the threaded piece - In SAPH 4A, the shearing was noticed in threaded portion.

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• The adaptor body if loosens and rotates even a bit, due to reaction force of the steam, the loosening will increase and when the nozzle direction comes to horizontal plane, the whole pipe will over shoot the limits, as seen the condition in SAPH 4B.

• The elimination of hot end soot blowers for SAPH - as the higher length and sweep associated with the exposure to high flue gas temp may be a reason for the failure.

BHEL Ranipet maintained that this design is OK. MILL SIDE PROBLEM:

1. Oil leak from mill gearbox radial bearing housing. The same was attended by calling unit’s representative.

2. The upper radial bearing temp. was going as high as 90 degree in most of the mills. The problem was traced back to the insufficient insulation in front of inspection cover & hence the PA hot air temperature is transferred to upper radial bearing in the inspection opening area. The same was attended.

ECW SYSTEM:

• M/s Kirloskar make motors - the cooling was not effective and the temp of the motor body was unbearably hot. M/s Kirloskar representative did trials with air passage in the end cover and after few trials a satisfactory uniform cooling is observed. Modification was done for the motors in the cooling system.

• The pump vibrations were remaining high and the pumps were highly maintenance prone and frequent bearing and mechanical seal replacement was required. In consultation with PEM, hanger & supports arrangement of the pipes modified.

• Vents /drains and subsequent connection to the common drain system were not indicated in the drawing and this poses problem to site for site erection group and contractors asking extra for the same. The same is to be indicated in the drawing.

• The butterfly valves in the system were passing making the stand by isolation and maintenance difficult. The M/s KBL, suppliers’ representative was called for the rectification of valves.

• Below the ECW Plate heat exchangers are the boiler ECW pumps and through the grating floor, wastewater falls on the ECW pumps. The floor above shall be concreted /chequered plated.

• The PG test for Plate Heat Exchanger could not be completed for want of instrumentation, it is recommended that during contract

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award stage the PG test requirement and instrumentation needs to be told and vendor should supply the same as part of main supply

ACW SYSTEM: NRV passing – M/s KBL engineer was called her and hinge system was found defective and the same was attended.

CW system – BHEL Bhopal supplied Butter fly isolation valves size 3300 was passing and condenser isolation was difficult. Technician from Bhopal was called and attended.

BOOSTER PUMPS MECHANICAL SEAL: (Supplied by M/s Eagle Punewalla)

The locking arrangement of the seal with the shaft was not proper hence the seal was getting loosened and causing the damage.

The supplier was called for the modification of locking arrangements. It is suggested that mechanical seal of M/s Burgman is to be used for booster pump also. MD BFP UNIT#3 - C&I PROBLEMS: Sl no

Description of the problem

Analysis Remarks

1 Premature failure of pencil type RTD’s in feed pump booster and main pump thrust bearings.

Failures are attributed 1- The interfacing

between element and connecting wire is very weak.

2- The pencil diameter is more than that of hole in the pad.

3- The take off cable supporting arrangement is not good and allow movement of the RTD.

4- The quality of the RTD is not up the mark.

1) Braided type RTDs should be supplied.

2) The tip dia of RTDs should match with the dia of hole of thrust pad of RTDs to ensure proper insertion of RTDs in thrust pad.

3) High temperature shrinkable protective sleeves should be used to protect RTD wires from mechanical damage (if any during running).

4) Routing of the RTD can be made better.

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2 Differential pressure across the mechanical seal water filter going beyond the gauge 0 to 0.5 kg/sq cm range.

1- The measurement of the DP across, when the filter elements are cleaned, is 1 kg/sq cm.

2- Selection of gauge or the filter size is not correct.

Proper range of gauge or filter shall be supplied.

3 DP gauge in the booster pump discharge main pump suction line filter is not functioning properly.

1- The with stand static pressure capacity of the gauge is only 15 kg/sq cm where as the line pressure is 28 kg/sq cm.

2- May be due to the high line pressure after some few hours of operation it is going bad.

Gauge of high static withstand pressure capacity shall be arranged as replacement.

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OTHER MINOR PROBLEMS FACED BY SITE : TG SIDE DESCRIPTION PAGE

NO

HP HEATERS UNIT#3&4 – MANHOLE DOOR LEAKAGES 37 HP BYPASS OIL PUMP FAILURES UNIT#4 37

TURBINE AUXILIARY PUMP UNIT#3 37 DRY FILTER ELEMENTS OF CONTROL FLUID REGENERATION UNIT

37

220V DC BATTERY ROOM 37 LP BYPASS VALVE UNIT#3 38

THERMOCOUPLE – IP CASING UNIT#3 38 PRIMARY WATER COOLER FLANGE LEAKAGE 38 TD-BFP BARRING GEAR 38

TD BFP CONTROL VALVE 39 JACKING OIL SELF ACTING PRESSURE CONTROL VALVE 39

CONTROL FLUID DRY FILTER ELEMENT 39 TURBINE DRAIN VALVES (ANGLE TYPE) 39 IP STOP VALVE (INTERCEPTOR VALVE) 39

MDBFP UNIT#4 40 FAILURE OF CEP-4A MOTOR 40

FD-14 VALVES 40 CONDENSER TUBE FAILURE UNIT#3 40

BOILER SIDE:

BURNER TILT 41

SADC POWER CYLINDER 41 HOT AIR DAMPER POWER CYLINDER CONNECTING LEVER BREAKING

41

BOTTOM ASH EVACUATION SYSTEM 42 DAMAGE OF ALEKTON MAKE HFO PUMP 42 APH OBSERVATION LIGHT 42

ID FAN DAMPER SHAFT 42 SAPH-3A FIRE 43

ID FAN MOTOR COOLING WATER COMPENSATORS FAILURES 43 ID FAN 4A INLET GATE ACTUATOR DAMAGE 43

AIR CONDITIOINING & VENTILATION 44

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TG SIDE:

HP HEATERS IN UNIT-3 & 4: Manhole door developed leakage while in service. The same was attended with the help of BHEL Hyderabad. FAILURE OF HP BYPASS OIL UNIT PUMPS: Type OV32B-50-201, SL. NO. 1Y97 Arial piston pump. In one of the HP by pass oil unit of Unit-4, the pressure was getting lost after initial commissioning, however other unit was developing pressure. After thorough checks on the system, it was observed that pressure getting lost in the system due to system peripherals malfunctioning. It was contained that the pump was not developing pressure. BHEL (T) has supplied new pump & the system was re-commissioned. TURBINE AUXILIARY OIL PUMP – DEVICE FAILURE: UNIT#3: The abnormal sound was noticed in AOP-3A during running, the pump was de-coupled and motor was run alone. No abnormality noticed. The pump was dismantled for inspection and following observed:

- Impeller locking nut with shaft was found loose. - The brass bush provided at the bottom end of the pump was

having rubbing marks on face and bush found loosely fitted in the end cover.

- Thrust bearing was found jam & damaged. - The end cover in which the bush fitted was having longitudinal

cracks on the top and bottom side of the threaded hole (for lock screw). The screw could not lock the bush due to its short length.

In another pump, a crack was noticed on the pump casing at the base of one of the casing studs. The vendor was called for the replacement/ rectification in consultation with BHEL Hardwar. DRY FILTER ELEMENTS OF CONTROL FLUID REGENERATION UNIT: in the upper filter got broken in both the units. Replaced with new ones. 220V DC BATTERY ROOM FIRE: On 19.03.2004, a spark generated by welding/ gas cutting gone inside the battery room through ventilator fan opening and ignited the plastic cover of the battery and caused to the damages to the 32 nos batteries 990AH type KPH990P & other items. Immediately fire was extinguished with the fire extinguisher installed in the battery rooms.

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The openings were temporarily closed with the GI sheets & burnt batteries were replaced from mandatory spares.

LP BY PASS VALVE IN UNIT#3: Not holding during hydro test. The valve was replaced and defective valve got rectified from BHEL Hardwar. THERMO-COUPLES OF IP inner casing lamp measurement failed. Planned replacement in the shut down/ overhaul. PRIMARY WATER COOLER FLANGE LEAKAGE:- gasket replaced. TDBFP BARRING GEAR: Turbine driven feed pump not coming on barring gear from stand still condition after maintenance like strainer cleaning after tripping out. Even after stabilizing the pump barrel temperature, some time pump was not coming on barring gear & hence starting of the pump was difficult. BHEL Hyderabad has cleared for steam rolling of the pump, if main pump top/bottom temp. differences is with in 22 degree centigrade and booster pump is free to rotate.

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TD-BFP CONTROL VALVE: Few control valve not opening more than 6mm, even with full servicing oil pressure. Servo motor was sent to Unit and got the same rectified. JACKING OIL SELF ACTING PRESSURE CONTROL VALVE (3 NOS.): The self acting pressure limit valve in the main turbine jacking oil system (supply from HWR-Baroda make) after few days of operation failed to maintain. The valves were repaired at the vendor works & again put back in service. Fault could not be traced. CONTROL FLUID DRY FILTER ELEMENT: burning due to static electricity. The vendor visited site & replaced the filler element. TURBINE DRAIN VALVES (ANGLE TYPE): M/s. Sampel make. More than 50 percent valves in unit#3, stands passing during service & the nature of failures are:

• Damage to the seating. • Spindle brakeage.

Vendor representative was called during the shut down of PG test & rectified the same by lapping /rectifying the spindle & seat as the case may be. The similar problem faced in the unit#4 also and vendor’s representative was called & rectification was done. Two valves needed to be replaced with new ones. The reason for the damage of seating & spindle is non-flushing of the pipe lines before installation of Sampel make turbine drain valves. The welding waste was found in the valves. IP STOP VALVE (INTERCEPTOR VALVE): (unit#4) Supply valve rack was having problem & hence the valves were not operating. IV oil rack, HP filter change over valve, teflon seating sealing, was getting damaged after few operation. Twice the seal was replaced. But the problem persisted. Even twice FRF oil was getting lost.

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The HP filter unit with change over valve was replaced from Vindhyachal unit & the defective rack is sent to BHEL Hardwar for repair. With the replacement, the isolation is perfect. MDBFP (Unit#4) got jammed twice and running with high vibration with pump cooling. On checking of suction & discharge piping for proper loading, pump intervals & reassembly did not yield desirable results. Finally the cartridge was replaced with new one from mandatory spares & the performance of the pump found satisfactory. Hyderabad technician was called for the rectification of the damaged BFP cartridge. The reason seems to be balancing drum/disc clearance as it was found to be more i.e. 0.75 against the design value of 0.41 to 0.48. FAILURE OF CEP-4A MOTOR: While starting the motor, the motor tripped on earth fault. On checking, it was found that motor winding failure in B Phase as reflected by the phase winding resistance & zero insulation resistance value. The motor was run for about 112 hrs at different intervals. The motor was replaced with spare motor & pump was taken in to service. The damaged motor sent to BHEL Bhopal for rectification. FD – 14 VALVES: Feed controls start up valve (tag No. FD-14) supplied by ILP, developed frequent problem of stem to plug disconnection during the operation of the valve. The problem was due to taper pin, which is wedged after screwing the stem in valve plug getting loosened and falling down &getting stuck during the movement of valve. The flow throttling effect caused the plug unscrewing & braking. With the vendor concurrence, in addition to tapering stem & plug at joint is seal welded & the problem did not appear again. CONDENSER TUBE PROBLEM (Unit#3): The unit was running between 400 to 500MW load, the silica & conductivity values of condensate increased to 29PPB and 6.05

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respectively against normal 8-13 and 3.3 during regular sample test on 30.07.2005. Primarily condenser tube leakages were suspected for the sudden rise in silica level. The unit was tripped for investigation. Candle leak test under vacuum did not show any abnormality. Hence it was decided to carry out the flood test:

- The condenser was isolated from CW side and the water boxes were drained.

- Condenser hot-well drained. - Condenser tubes thoroughly cleaned with compressed air to

ensure no water in the tubes. - Condenser locking springs locked. - Condenser steam space was filled with water just one meter

above tube nest. Thirty three nos (33 nos) condenser tubes were found leaking (24 nos from pass A water box & 9 nos at pass B water box). Most of tubes were found in the middle fingers of the condenser. The defective tubes were plugged. (Duration 30.07.2005 to 04.08.2005). None of the leak was from expansion joint, leakage observed from inside. Manufacturing defect was suspected for early failure of the tubes.

BOILER SIDE: BURNER TILT, In both units, we experienced the problem of coal nozzle movement problem to the required value. Extensive re-work in removing the interference was necessary. SADC POWER CYLINDER, The power cylinder, peripherals were either unapproachable/ interfering with structures in corner No. 2 & 4. Suitably structure modified at site. HOT AIR DAMPER POWER CYLINDER CONNECTING LEVER BREAKING : PA hot air damper power cylinder connecting lever to the damper shaft lever was breaking very often. We have to replace total 8 levers in both the units. Initially the lever was of cast iron, we suggested the supplier for cast steel lever.

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The problem of breaking resolved after: 1. Change of lever with cast steel. 2. Alignment of linking rod. 3. Mounting of power cylinder with a provision to accommodate

thermal growth. BOTTOM ASH EVACUATION PROBLEM: The unit#3 was on full load, boiler bottom hoppers were filled with the clinkers and ash. (27-09-05 to 29-09-05) The unit is to be tripped, BHEL Trichy representative was called to study the problem and informed that ash evacuation and clinker grinding are not working properly and to be looked into by the ash handling agency. NTPC made modifications & problem resolved.

DAMAGE OF ALEKTON MAKE HFO PUMP: Pump identification: Alekton triple screw pump, Model no DH 600-1600-2SJ, Sl no 03033374 Application: HFO pumping for unit#3 & 4 The pump was found seized. The possible reason may be suction valve was closed by mistake and pump has run for some time. On opening of cartridge, pump screws & inserts were found damaged. The cartridge was sent to the supplier’s works for replacement of screws & inserts and balancing. Assembled at site & trial run of 4 hrs completed and handed over to NTPC. APH OBSERVATION LIGHT: The bulbs of all air pre heaters observation port got fused over a period of time. The replacement of bulbs while in service is not possible. This is being done only during shut down only. ID FAN DAMPER SHAFT: The ID fan inlet damper shafts failed during pre-commissioning operations twice. This was due to fabrication problems at manufacturing unit. Replacement shafts were sent by Ranipet and problem resolved.

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SAPH - 3A FIRE: During light up for ABO of unit#3, SAPH-3A fire was noticed. The fire was noticed in the initial stage itself.

- Only one outboard segment of one module got damaged & replaced. A few hot end radial seals were also replaced.

- The possible fire may be due to accumulation of preservation oil.

- The ducting works connecting to the air heater is thoroughly checked for any inflammable material and cleared.

- Both hot end and cold soot blowing were run continuously for considerable time to clear of the preservative.

- Monitoring on the flue gas side was made by providing a window as additional precaution measure.

- The fire sensing probe which was inside the holder very much was brought in line with the guide pipe edge to increase the response.

SUGGESTIONS:

- Acoustic type soot blowers are gaining importance and Ranipet shall make an attempt to evaluate the same to our application especially in the absence of steam.

- Dry type of preservative shall be better option because of the preservative is oil type and it is like highly viscous tar like and it is not getting cleared either by water jetting or by steam jetting.

- In-fact to clear the preservative soot blower was operated with steam in the cold end for many hours.

ID FAN MOTOR COOLING WATER COMPENSATORS FAILURES: The cooling water expansion bellows of ID fan motor were failing one by one. This may be due to withering effect of rubber materials. New compensators were procured and replaced. ID FAN 4B INLET GATE ACTUATOR DAMAGE: When unit#4 was in operation, the body of actuator gear box was broken and its motor damaged. The gate is not normally closed even during shut down, only inlet damper is closed. It was suspected that somebody from control room operated the actuator and due to over traveling the actuator body was broken. The limit switches did not work. The actuator was sent to its supplier M/s Limitorque India Limited for replacement of parts & repair.

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AIR CONDITIOINING & VENTILATION: MAIN AC EQUIPMENT ROOM: Both the screw chillers of 220 tons each (Make – Carrier, China) damaged during the erection. The supplier’s representative was called & replaced the refrigerant (R134A), oil, oil valves, copper tubes, driers, insulation, HP switch & sensors. PAHARPUR COOLING TOWER: while lifting the fans, one out of four, the shaft & blade assembly damaged. The new assembly procured and replaced. AIR WASHER FANS (MAKE – FLAKT INDIA) type DYDL-194: One no installed at 23 mtr having problem of shaft bend & damage of inlet cone & bearing during transit. The supplier was called for rectification.

Another fan at 8.5 mtr above ACW building failed during commissioning. Its shaft got broken, with a result impeller, inlet cone, bearings & belt got damaged. The impeller being the size of 1940 mm was the problem of removal from the room. NTPC modified the room by removing the wall from one side & provided of shutter for future maintenance. SERVICE BUILDING: Both the screw chiller of 275 ton each damaged during erection in service building. Its refrigerant, oil & copper tubes were to be changed. AIR HANDLING UNIT (Make: MNW Calcutta): Cooling coils found punctured; supplier was called for the rectification.

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MAJOR PROBLEMS/ FAILURES:

DESCRIPTION PAGE NO

FAILURE OF MAIN STEAM STOP VALVE MSV-01 (UNIT#3) 46

COLD REHEAT LINE HAMMERING & FAILURE UNIT#3 47

GENERATOR EXCITER END BEARING TEMP. GOING HIGH UNIT#3

50

CONDENSATE STORAGE TANK – CAVING IN 51

CONDENSATE PUMP FAILURES 52

GENERATOR TRANSFORMER FAILURE UNIT#3 53

BOILER UNIT#3 TUBE FAILURES 56

FAILURE OF MAIN STEAM STOP VALVE MSV-02 (UNIT#4) 59

DC JACKING OIL PUMP UNIT#4 59

TURBINE UNIT#4 – FINAL CRO VALUES 61

TD BFP – TURBINE LUB OIL PUMP FAILURE 62

HOT AIR SHUT OFF GATES UNIT#3&4 63

GENERATOR ROTOR REPLACEMENT (UNIT#4) SEAL OIL PROBLEM

65

CONTROLLED CIRCULATION PUMP – KSB MAKE 66

FD FAN 3A (API 26/16) BLADE FAILURE 68

NMEJ’S FAILURES IN UNIT#3 70

BOILER #4 TUBE FAILURE AFTER ACHIEVING FULL LOAD ON 15.02.2006 (LTSH TERMINAL TUBES FAILURE)

73

PA FAN 4A – BEARING VIBRATION PROBLEM 76

FEED WATER SYSTEM – INPUT SHAFT OF GEAR BOX. 77

BOILER HOISTS – CABLE TROLLEY 78

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FAILURE OF MAIN STEAM VALVE MSV-01 (UNIT#3)

The main steam valve also called boiler stop valve, isolates boiler from turbine and thus performs a critical function. The valve was commissioned electrically on 24/11/2004 and put on service for steam blowing operation. The first stage steam blowing commenced on 27/11/2004, which was completed on 02/12/2004. On 02/12/2004, it was found that the valve was not operating from remote (control room). Visual inspection did not suggest any problem. Attempts to open the valve manually failed, as the manual lever was not getting engaged. Electrical operation was then tried, heavy metallic sounds were heard from the actuator gear box and the valve was not opening. Actuator top cover was opened and gear mechanism was inspected for the source of metallic sounds heard during electrical operation. Some of the gear teeth apparently have broken. The actuator was then dismantled, as it was not operating either manually or electrically. On removal of actuator attempts were made to jack up the stem initially by 2 X 20 MT hydraulic jacks but stem was not getting lifted up. It was then decided to heat up the valve body by coil heating and then jack the stem up by 2 X 100 MT hydraulic jacks, the stem was finally jacked up on 04/12/2004. The actuator was dismantled from unit#4 boiler and assembled with the failed MS stop valve after the stem was jacked up. The MSV was out back into operation on 05/12/2004 and the 2nd stage steam blowing commenced the same day. The reason for failure of the valve seems to be over traveling of the stem during closing. This may have been due to failure of the limit switches or some other electrical components. An expert from Valves division Trichy and M/s Limitorque India Limited engineer (actuator supplier) was called to assess the extent of damage. Fortunately the damage was very minor, only worm shaft clutch was found damaged, which was procured from supplier and fitted with the damaged actuator MSV-1 for unit#4.

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COLD REHEAT LINE HAMMERING & FAILURE (UNIT#3) On 28/03/05 when unit-3 was steaming with AB and CD elevations oil burners for boiler safety valve floating with HP-LP bypass manual operation. At 13.24 hours CEP 3#C tripped due to pressing of EPB at local by bystander, and due to this other running pump tripped on discharge pressure low. The LP by pass valves closed on interlock. Since the HP-By pass valve on manual, the Reheater system pressure rose and operator intervened and closed the HP by pass valve in steps and the MS pressure increased from 170 to 185 kg/sq-cm After few minute HP by pass valve was again opened little, and this operation resulted in severe water hammering, immediately operator closed the HP by pass valves. DAMAGES: 1-Most of the cold reheat line hangers/restraints/rod support from Y piece to turbine inlet suffered severe damage and supporting structural also found damaged.

Primary damages 1 CRH line supports 26 out of 43 nos needed replacement of

assembly/components[inclusive of 8 rigid stud hangers of 250 kilo newton capacity]

Secondary damages 1 HRH line 2 nos in CD bay 2 MS line 1 no in TG bay 3 HP by pass down stream 3 nos 4 Extraction steam to

Dea. 5 nos

5 CRH to aux steam 1 no 6 Extraction to HP

heaters 3 nos

7 LP by pass valve 1 no

2 –Few hangers adjoining to the cold reheat line hangers suffered damage. 3- HP by pass oil lines got damages and oil lost. 4- Some of the instrumentation work got dislodged at the Y piece area. 5- Few Boiler connecting members of column got bend. 6- The cold reheat level pot switch is damaged. 7- Insulation got damaged due to falling of members on the insulated pipe. 8 The CRH pipe line initial co ordinates disturbed in all direction. CRH line near Y-piece has shifted by 200mm in (-) X & 300-400mm in (-) Y direction.

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RECOVERY PLAN:

• Removal of insulation at the selected location for putting the lifting arrangement, inspection of attachment welding integrity, branching pipe weld joint integrity.

• Removal of damaged structure and supports. • Assessment of damages of supports along with PC Chennai and

PEM along with NTPC. • Putting up the aux structure and supports. • NDT checks for the integrity of weld. • Alignment of the pipe. • Transfer of pipe load to hangers and adjustment of the hangers

as per the hanger schedule. • Submission of the cold setting values to PC/PEM and NTPC for

approval. • Releasing for turbine horn drop test. • Final release of pipe line for use.

OBSERVATIONS: The controls are based on MAX DNA system which is new and being introduced first time for 500MW. The trend curves during the period of operation reveals following: BPE valves 1-The BPE-1 valve has opened even when the BP-1 valve closed less than 2 percent. 2- BPE-1 valve opened twice during the period. 3-BPE-2 valve remained closed. BD Valve 1-BD valve remained open. 2-MS pressure - 170 to 185 kg /sq-cm. Analysis From the event summary and trend curves of the HP by pass system on the day of incident, it is seen that main steam pressure approximately 185 kg/cm2, BD valve remained open and BP-1 steam valve position was –2.8 percent and spray valve BPE-1 feed back was more than 50 percent for few minutes twice. This operation explains the cause for induction of water to CRH line. The simulation of HP by pass control system with conditions prevailed on the day of incident that with BP-1 valve in close condition with negative position feed back (- 2.8 percent) drives the spray valves BPE-1 to open as per the final processed out put which is more than 100 percent.

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BD valve remained open as the over riding command was hooked up wrongly in the software. With boiler under high pressure and lacuna in the controls has caused the CRH hammering. The logic out put for the final element is given.

FORCED INPUTS

LOGIC OUTPUTS

MS Press

BP-1

Pos

PID 4

Sigsel 8

Funcgen 1

Mul 3

Add 52

Add 5

Add 6

Mul 9

Cmpt 51 i/p

Remarks

185 -2.8 -0.056 -50 -1.4 -129 -50.1 -79.5 -74.5 149 149 Output is driven to full

in the positive direction

SUGGESTIONS:

BPE valves This condition has resulted in opening of BPE-1 valve. Since the feedback values can go negative at any time for any reasons. This negative value is required to be clamped to zero to avoid such situation and fault can be annunciated and control action shall remain frozen, where as BPE-2 valve remain closed as BP-2 valve position was 0.8 percent.

BPE-1 valve remaining open despite of BP1 valve feedback as less than 2% BPE valves should be given Force Close Signal when corresponding BP- Valves are less than 2% open.. Refer [3HPBP] TEAM/HPBP/LOGIC/BPE1- VALVE/BPE1-CTRL. This is implemented at A/M Station (Custom Block: Outcast, Tag name: 3MAN20AA100_XS01, Block#6), which does not act directly on the valve. This has not closed the valve on less than 2% opening as the Command from CMPT –51(Refer [3HPBP] STEAM/HPBP/LOGIC/BPE1-VALVE/PID), is presently going directly to the Valve Interface Module. The CMPT-51 output can be routed through A/M station, which has override features for Force Close.

BD valve remaining open despite of BP1/BP2 valve feedbacks are less than 2%: Refer [3HPBP]/UNIT3/STEAM/HPBP/LOGIC/BD-VALVE (OR-3 Block), the auto-opening command (MASTER-PR –CNTRL/PID/#1.Outctl value

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was greater than 2%) inhibited the BD valve to close even if BP1/BP2 valve feedbacks were less than 2%.

Conclusion Since the Max DNA control is new and entirely different from the conventional pro control, and site is not aware of the effect of negative position feed back of the BP valves can cause this much catastrophic incident involving much loss of time and face.

From the above it is seen that mal-functioning of controls on the position feed back has caused all the troubles.

The proposed changes, which in our opinion will enhance the operation flexibility shall be studied by EDN and implemented quickly.

It was also recommended that all the controls where the position feed back drive the final control elements shall be checked for the above phenomena by EDN. FINALLY AFTER RECTIFICATION OF CRH LINE, BOILER WAS LIGHTED UP ON 25.04.2005 GENERATOR EXCITER END BEARING TEMP GOING HIGH: (UNIT#3) On 10.05.2005, when unit was running on part load with coal firing, the rear bearing temperature of generator was found increasing up to 95 deg C & nearing to alarm level. Load reduction and idle running did not give any relief in temperature. The unit was tripped & arrangements were made to open the generator bearing, a rubber cord of 4 mm diameter & 300 mm long was found stuck in the bearing oil pocket, likely entry & subsequent travel to Bearing no 6 could be from pipe flange, filter units, blocking the oil passage and restricting the oil flow. The scratches were also found on the bearing. Action taken

1. Bearing was replaced with new bearing and defective bearing was sent to Hardwar for rectification.

2. Alignment checks. 3. Oil flushing of the bearing oil supply line. 4. Checking oil filter for the O rings.

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Exact cause cannot be ascertained. This is an isolated case. Extra precaution & care can prevent such occurrence. Problem resolved on 30.05.2006. CONDENSATE STORAGE TANK CAVING IN: Two nos condensate storage tanks (CST) of capacity 888 meter cube each were installed for 2X500MW stage-II Rihand STPP in January 2005. The purpose of the CST is to store the DM water supplied from the DM plant and deliver it for hotwell make-up & ECW tanks make up. Both the tanks were in continuous parallel operation since commissioning of unit#3 in January 2005. On 08.07.2005, it was noticed that roof of one CST has caved in. The tank was isolated and following observations are made:

• A segment (about 150 deg.) of roof plate (8 mm thick) found caved in. (deflected towards inside)

• Main rafters (ISMB 150) – 9 out of 20 nos found bent and twisted.

• Cross girders (ISMB 100) – 9 out of 20 nos found bent and twisted.

If appears that, the tank has carved in due to sub-atmospheric pressure generation at high with drawl of water from tank & breather circuit being non functional as evidenced from the solidification & blockage of passage. The vendor M/s Sakthi Hi-tech constructions Private Limited was informed for the failure immediately and a detailed procedure was made for rectification as under:

• Drain condensate water from the tank & empty it. • Disconnect all the pipes connected to nozzles. • Open shell manhole and arrange proper illumination inside tank. • Scaffolding arrangements inside tank & remove the rafters. • Jacking arrangement with ISMB 300 to pull the dent and arrest

with the beam. • Repeat the above till the entire dent is removed. • Repair the damaged rafters & re-fix inside & release the beams

at top. • Wherever dents are not removed, cut & remove the roof plates,

correct it by heating/ hammering/ pressing or replace with new plates and erect, align & weld roof plate.

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• Restore the pipelines & carryout the pneumatic test on the roof plate weld joints up to 150mm of water column.

• Apply the paint, wherever hot work is done. The repair work completed on 13.12.2005 and hydro fill test of tank was carried out on 31.12.2005. The breather tank provided is not basically a breather tank but a seal tank. Hence in case of vacuum, the NaOH solution along with atmosphere air shall be drawn in to tank and contaminate the DM water with NaOH. At present the breather tanks in CST are not filled with NaOH solutions. It is recommended to have vacuum breaker valve to prevent occurrence of such failures for both sub atmospheric & above atmospheric pressure condition.

CONDENSATE PUMP FAILURES: AA) Thrust bearing failures occurred in 2 nos CEP of unit#3 (CEP 3B & 3C): Operating temperature at CEP is around 67 to 70 Deg. C. recommended alarm set point is 95 Deg. C & trip at 105 Deg. C. CEP was tripped on alarm itself & damages to bearings observed. In present arrangement sensing tip of RTD is away from Babbitt, as such actual temperature at Babbitt is likely to be more. The reason of bearings failures was leaking cooling water from the sump cooler union connection entered the bearing housing and contaminated the oil. Water leakage, ingress can be prevented by -Cooling water connector presently brass fittings, can be provided as C.S./S.S. for similar metal connection at site i.e. same as connected piping. -Fitting to be located away from bearing to avoid any changes of water ingress. -Approach platform to thrust bearing so as, inadvertently also cooling water piping is not used to climb resulting in likely damage to connector & possible leakage there on. The problem resolved by taking out the union joint so that water will not enter in the bearing in case of leakage. An approach provided for

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regular inspection of bearing. Now both in Unit- No. 3 & 4 alarm set point kept is 75 Deg. C & trip at 85 Deg.C under intimation to Hyderabad unit. Duration 11.08.2005 to 17.08.2005. BB) CEP seized during the running. The reason was shaft key provided between shaft and sleeve got slipped from its position, resulted in relative motion between shaft and sleeve and hence over heating & ceased the pump. The pump was replaced with unit#4 immediately. BHEL Hyderabad technician was called for the repair of pump at site and put back in unit#4. CC) Frequent failure of CEP Motor DE bearing (CEP4C): Motor DE bearing housing was not centered and the bearing housing clearance was more. The defective housing was replaced by a new one by BHEL Bhopal and problem resolved.

GENERATOR TRANSFORMER FAILURE UNIT#3: 214 MVA GENRATOR TRANSFORMER

SL NO : 6005990 (B Phase) As a part of operation checks, Oil samples were taken on 10.06.2005 and tested at NTPC R&D laboratory Noida. The results were received on 29.06.2005 and gas contents (C2H2, H2, C2H4, CH4, C2H6 etc) were found to be much above normal permitted levels and NTPC Noida asked for sample for retesting. Further samples were taken on 30.06.2005 and tested at NTPC Vindhyachal and NTPC Noida. Sample test results showed further increasing trend of gases content, which were suggestive of conductor overheating as possible. The matter was referred to BHEL Bhopal on 30.06.2005 and they have advised the said Transformer be taken out of service and thorough inspection of transformer internals in presence of BHEL Bhopal experts be arranged in a properly covered area due to rainy season. The isolation & dismantling of Transformer started on 02.07.2006. When a critical fault is detected in a large size transformer, and replacement of transformer is needed, the outage time is directly

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linked to the loss of generation. It becomes very vital to bring back the unit to save the generation loss. Under this consideration, dry- out process for transformer filtration needed improvement. At sites, with the limited available infrastructure, the improvement in dry out process was conceptualized and implemented at Rihand STPP.

• The increase in flow of oil of 10 KL for fast recirculation was achieved by deploying additional 4KL filtration machine in addition to existing 6KL filter machine by using additional “T-off” connection from suction valve, and using additional valve from top (delivery) header. The impurities were removed at a faster rate. Thus early achievement of transformer oil BDV and completion of filter process.

TOP HEADER

BOTTOM HEADER

SUCTION

DELIVERY

DELIVERY DELIVERY

SUCTION

SUCTION

S

4KL OIL FILTER M/C#

1

6KL OIL FILTER M/C# 2

• The improvement in easy access to moisture: Advantage was taken from water properties during various stages of heating process. During initial stages when temperature of oil is lesser, the water being heavier than oil , the suction to filtration m/c

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was taken from bottom, so that oil with more moisture is taken from bottom and delivery to top avoids mixing of oil. After temperature rise moisture tends to convert to vapour form and gets collected on top. Suction to filter machine was taken from top.

TOP HEADER

BOTTOM HEADER

DELEVARY

SUCTION

DELIVERY DELIVERY

SUCTION

SUCTION

S

4KL OIL FILTER M/C#

16KL OIL

FILTER M/C# 2

• The following method for dragging GT 214MVA containing weight

about 175 MT in assembled condition was used in stead of conventional method of chain pulley block for faster movement:

GENERATOR TRANSFORMER 200MVA

DIRECTION OF MOVEMENT

S

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Replacement & charging with spare transformer completed on 13.07.2006 and saved at least 4 days. The damaged transformer shifted to stage-I maintenance bay for the inspection. BHEL – Bhopal team visited to site three times between July to November 2005 for the internal inspection, but no conclusion could be reached and finally transformer was dispatched to BHOPAL for further investigation on 27.11.2005. PRESENT STATUS: The transformer is still under investigation at BHEL Bhopal & HV test could not yield the result, likely to be put on heat run test.

BOILER UNIT#3 TUBE FAILURES:

The unit#3 was first synchronized on 26.01.2005 on oil firing. The machine was shut down and synchronized time to time as per operational requirement of the unit.

The Boiler light up was done at 12.30PM on 26.08.2005.

-Rihand stage II unit 3 was running at full load.

-On 28/8/05 around 0400 hrs there was sudden increase in make up water requirement. Subsequent inspection in boiler area confirmed tube leakage in boiler first pass and unit was shut down for detailed inspection.

-After initial cooling of boiler and making approach, inside pressure parts were inspected. The observations were as follows:

Primary damage - Divisional panel DNP-8 second row counting from left approximately at 64 mtr elevation towards super heater platen side, second tube was found snapped at the welding joint.

Secondary damages 1. The snapped ends of the dnp-8 second circuit have struck in the

other divisional panels’ dnp-7, dnp-8 etc and damaged 10 tubes near roof level.

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2. Other end of the snapped tube has got stuck up in 12th coil of the platen super heater (counting from left side) and has damaged the near by coils.

2. Reasons for damages: it was suspected that the welding joint was weak. 3. The damaged tubes were replaced with new one. The total joints welded, were 144 nos consisting of materials T-11, T-22, T-91, SS-347 and dissimilar joints (T22-T91). Trichy FES representative was also called for the on the spot study of tube failures. TUBE FAILURES, AFTER COMPLETION (09/10/2005) OF TRIAL RUN OF 30 DAYS CONTINUOUS RUNNING:

12/07/2006 TO 14/07/2006: At approx 22 mtr elevation transition tube 90 deg bend 1st tube at corner 1 pin hole leakage from suspected flame cut during erection. 15/07/2006 to 16/07/2006: Steam cooled wall RHS failed due to poor weld on flame cut repair during erection of tube panel.

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FAILURE OF MAIN STEAM VALVE MSV-02 (UNIT#4)

The main steam valve also called boiler stop valve, isolates boiler from turbine and thus performs a critical function. The valve was commissioned electrically on 03/07/2005 and put on service for steam blowing operation. The stage steam blowing commenced on 07/07/2005, which was completed on 26/07/2005. On 15/12/2005, it was found that the valve was not operating from remote (control room). Visual inspection did not suggest any problem. Attempts to open the valve manually failed, as the manual lever was not getting engaged. Electrical operation was then tried but the valve was not opening. The actuator was then dismantled, as it was not operating either manually or electrically. On removal of actuator attempts were made to jack up the stem initially by 2 X 20 MT hydraulic jacks but stem was not getting lifted up. It was then decided to heat up the valve body by coil heating and then jack the stem up by 2 X 100 MT hydraulic jacks, but the stem could not be jacked up. An expert from Valves division Trichy was immediately called for attending the problem. As the valve stem was not coming out, it was decided to open the main steam valve and remove the stem by cutting it by gas cutting. A new stem, disc & sleeve and other consumable items were asked to send immediately from BHEL Valves Trichy for the rectification of valve. Finally the valve the rectified on 29.12.2005 and tested electrically & put into operation. It seems that some foreign material got struck up and jammed the valve operating mechanism.

DC - JACKING OIL PUMPS (UNIT#4): Two nos. of DC motor driven main Turbine Jacking oil pump. Module SDF A80 R46G9-W112Sl. No. 79366/1(19/059), 79365/01(16/07). DC motor driven Jacking oil pump make – M/s. Allweiler, Germany, which was commissioned on 04/07/05 & 4 hours trial of the pump was very much satisfactory. The speed of pump was 2925 RPM and the pump discharge was 178-180 Kg/Cm2 with motor current as 215 Amp. The vibration measured during running, observed to be normal.

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On 1st September 2005, DC JOP was run for 3 hrs along with other DC motor driven auxiliaries for testing the battery load. On 7th September 2005, turbine was on barring gear with AC JOP, the DC JOP started on auto due to jacking oil header pressure low. The DC JOP was in service for 8 hrs. On 13th September 2005, during testing the Diesel Generator Capacity, D.C. Jack up pump could not be started due to some electrical problem in the control circuit of the DC starter panel. The same was attended and the pump was started, but it was not developing pressure. The motor current was only 30 amps (no load current) against the previous measurements with load of about 220 amps. On dismantling the DC JOP, drive shaft just below the coupling hub found in sheared condition. The surface cracks at the end of shaft and discoloration was also noticed, besides the pump found in ceased condition. One new pump, which was supplied as commissioning spare was replaced & tried with open discharge flange (before the NRV) & after establishing oil flow, pump was stopped & discharge connections were restored. When pump was taken into service, it failed again in similar fashion of shearing the pump shaft. Since the root cause for the repeated failure of the JOP shaft could not be identified, it was decided to call the vendor’s representative (M/s ARCUM) along with BHEL Hardwar engineering for establishing the reason for failure. On 21st September 2005, in the presence of M/s Arcum’s representative one more pump was arranged from mandatory spares and following checks were made before assembly:

• DC motor slow run & checked the direction, found ok. • MOT oil level. • Suction pipe line height. • Suction and discharge passage through compressed air. • Function of safety relief valve on the pump discharge at the set

pressure. • NRV functioning. • Coupling insertion, coupling gap and alignment.

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With the above checks, the new pump was put in to service on 22nd September 2005 and the operation was found satisfactory. The operation of pump from CCR and its auto start/ stop was checked and found all right. The failure is due to binding of the screw & reason for binding is not established. The damaged JOP was sent to overseas supplier M/s ALLWEILER AG for finding the cause of failure.

TURBINE – FINAL CRO VALUES - UNIT#4: During the final values of coupled run out (CRO) and swing after reaming, honing & fitting of bolts of HP-IP & IP-LP coupling and TG deck floating, were as under: CRO at journal -1 : 0.02 mm CRO at journal -2 : 0.06 mm CRO at journal -3 : 0.035 mm Swing at journal -1 : 0.023/0.24 mm The CRO at journal -2 was on the higher side. CRO on journal – 2 even without LP-IP coupling was found as 0.045mm. The above values earlier in hammer tight condition (without stretching) were as below: Before reaming &

honing with loose bolts After reaming & honing with fitted bolts

CRO at journal-1 0.02 mm 0.01 mm CRO at journal-2 0.03 mm 0.03 mm CRO at journal-3 0.02 mm 0.02 mm Swing at journal-1 0.08 mm 0.06 mm Several attempts were made at site by re-adjustments of the couplings but the values could not be brought within limits. Hence, the problem was referred to steam turbine engineering of BHEL Hardwar. As per site records of coupling face run out measurement at site, LP rotor TS coupling face had a run out of 0.0425/ 0.045 mm, which as per shop record was 0.02 mm. In consultation with BHEL Hardwar, it was decided to improve the values by improving LP rotor face (TS) run out by opening of IP turbine casing and removal of IP rotor to get the access. While correcting IP-LP coupling, HP-IP coupling also will be improved. The

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following activities involved in the rectification of coupling face run out:

- Removal of insulation to the extent required for dismantling top of IP casing

- Opening of IP top inlet pipe flange. - Loosening of IP outer casing parting plane bolts & lifting of

top half coupling. - Loosening of IP inner casing parting plane bolts and

removal of top half casing. - Decoupling of IP rotor from HP & LP rotors. - Lifting of IP rotor and keeping on the stand. - LP front coupling run out checking and correction by

scrapping/ blue matching till satisfactory reading is achieved.

- HP rear coupling face run out check and correction by matching till satisfactory reading is achieved.

- Checking IP rotor front and rear coupling face and rectification.

- Placing back IP rotor in position, coupling with HP & LP rotors and checking CRO, swing check etc with loose bolts as well as fitted bolts.

- Removal of IP rotor, final cleaning of bottom half casing and placing the rotor finally in position.

- Box up of IP inner casing and heat tightening of parting bolts.

- Box up of IP outer casing and heat tightening of bolts. - Final alignment checks of HP-IP, IP-LP corrections and

tightening of coupling bolts. - CRO and swing check of HP front. - Tightening of IP inlet pipe flange (top) and heat tightening

of bolts. - Re – insulation of IP turbine casing.

With the above, CRO & swing checks readings were improved within the permissible limits and during rolling & synchronization, the vibrations were observed far below than the limits. The above rectification work took nearly a month.

TD BFP – TURBINE LUB OIL PUMP FAILURE: TUSHACO MAKE T3 S140140 (UNIT#4a)

On 06-03-2006, running lube oil pump (shop assembled and skid mounted –Tushaco make screw pump) tripped on motor overload

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protection. On inspection, the pump was found jammed. This pump was in service during entire oil flushing and subsequently for another 3 months.

The pump was dismantled and representative from Tushaco Delhi as per the instruction from BHEL Hyderabad was called on 13-03-06. On dismantling the pump, following observations were made:

• Scoring marks were noticed on the idler screws – in Bush area & inside the liner bores.

• Clearances of the bushes and the idler screws were found increased beyond design limits.

• Some foreign material was found sticking to the screws, which could be removed by polishing. The entry of foreign material was main cause of failure.

The following items identified for replacement: 1-Bushes part no 8 2-Casing insert- part no2 3-Gaskets set part no 21,22,&24 The pump was sent to vendor’s workshop for reconditioning. After the rectification at vendor works the pump was put into operation.

HOT AIR SHUT OFF GATE: MECHANICAL:

1. In one of hot air gate, Blade was having bow at middle and the blade is seating over the retainer plate of bonnet side in open condition towards up stream side.

2. Misalignment between of power cylinder & gate, which promote sticking with sides.

3. The blade protection cover prohibits inspection of the piston gate connection and limit switch lever adjustment. Some times the removal of cover is very expensive & tedious job as about 150 nos of nut & bolts connection are to be handled. It is to be reviewed for elimination of the cover and if the cover is necessary, provision of inspection opening cover with swing arrangement shall be thought off.

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4. The side transition box connection for seal air to the seal chamber done at works invariably leaks and after connecting the seal air pipe, attending the leak difficult requires extensive re work and only temporary measures like application of M-SEAL is solution, which is not acceptable and becomes permanent pending point.

5. The bore of gaskets used for fixing the flanged butterfly valve in all the assembly was found less and hence prevent valve opening. Site has to remove the valve assembly and correct which consumes time and effort.

6. The out side seal box cover fixing with the seal box frame, the bolting system at present, makes removal of bolts difficult as the whole bolt rotates as the head tack welding with frame gives way and rotates.

POWER CYLINDER OF HOT AIR GATES:

1. The rubber seals of power cylinders in 7 out of 10 in unit#3 and 3 out 10 in unit#4 were to be replaced after erection due to piston seal passing. The piston seal should be good viton quality having high temp withstand characteristics and reliable lip reversal. To open the power cylinder weighing more than 250 kg at 45 mtr elevation, specially where no platform / beam is available above power cylinder, and bring down at ground level is a very risky & tedious job. We have to call the supplier’s technicians for the replacement of seals.

2. The requirement of lubricator shall be eliminated. 3. The Air filter regulator shall be of metallic than plastic which is

prone for damage.

ELECTRICAL 1. The junction boxes location is the top of the frame and hence

approach is difficult for any checking and maintenance. The location of JB was changed at site.

2. The limit switches assembly is provided in the up stream side of the gate makes it difficult for attending any defect due to heat while boiler is in service. At site, modification was carried out to suit the O&M requirements.

PNEUMATIC CONNECTIONS

1. The copper tubing is prone for theft and it is to be reviewed for switch over to flexible hoses/ SS tubing with hoses at ends.

2. The requirement of lubricator shall be eliminated with usage of seals which operate on dry air.

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3. The Air filter regulator body shall be of metallic and not plastic one as presently supplied which is prone for damage and it happens during erection and no spares are supplied. We have to procure 5 nos from the party.

CONTROLLED CIRCULATION PUMP (CC PUMP): M/s KSB Germany make.

In one of three CC pumps installed in Boiler#4, 4 nos studs were struck up in the casing at the time of removing the dummy after the hydro test of boiler. These were removed forcibly by heating and hammering causing the damages of all the four studs/ nuts and thread damage of the casing. The new studs (4 nos), nuts (7 nos) & jointing ring (1 no) were procured from M/s KSB Germany and the threads of the casing were rectified at site with the help of M75X2 tap sets. This last pump was commissioned without the help of vendor’s representative. It is recommended to follow strictly the Erection and O&M manual while heat tightening the studs with the casing, using lubricants & torque wrench supplied with equipments.

GENERATOR ROTOR REPLACEMENT (UNIT#4): GENERATOR SEAL OIL PROBLEM: Generator seal oil system was commissioned and put in service during first barring gear operation unit#4, on 31.08.2005, since than it was in continuous in operation, except for short shut down. The parameters during its operation were normal (DP at TE and EE were maintaining at 1.713 & 1.650 Kg/Cm2 respectively with seal oil temperature 36 deg C.) Unit#4 was re-synchronized on 05.12.2005 on coal firing successfully, and was kept in operation for further loading. On 07.12.2005 unit had to be hand tripped due to CEP tripping. The unit was started after attending the CEP problem on the same day.

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The turbine was rolled to 3000 RPM, it was noticed that the differential pressure (DP) at exciter end between seal oil pressure air side & hydrogen side in stator, dropped below the alarming level of 0.9 Kg/Cm2 (as read by pressure transmitter) & DC seal oil pump started on auto. The reading of local pressure gauge (air side), mounted on the seal oil valve rack was checked and the value was found normal as 5.6 Kg/Cm2. There was a difference of 0.6 Kg/Cm2 between the pressure gauge and the transmitter taking into account the head correction. DC seal oil pump was stopped and DP at control room found 1.1 Kg/Cm2 at exciter end. Clearance was given for synchronization. The unit was synchronized and loaded at 53MW load, it was noticed that DP suddenly dropped to 0.8 Kg/Cm2 at CCR as indicated by the pressure transmitter. Pressure drop in air side seal oil pressure as well as hydrogen side was noticed in the local pressure gauges & increase in air side oil flow (Exciter end) was also noticed. Besides hydrogen pressure was dropping gradually, as read by both pressure gauges & transmitter. Adjustment of exciter seal flow & AP regulators, did not yield desist results & hence machine has to be stopped on 07.12.2005 for inspection & cause of sudden malfunctioning of generator seal oil system. The following checks were carried out:

• Since air side seal oil pump discharge pressures (both pump 1&2) were high at 12 Kg/Cm2 as against the normal operating pressure of 8.5 Kg/Cm2, choking of filter elements was suspected. Hence the filter elements were cleaned and installed back, but there was not much improvement in the pressures.

• The operation of the air side DPRs, was checked and found OK. • Air side seal oil flow was increased by opening the throttle valve

and also by throttling the ring relief flow, but no appreciable increase in air side seal oil pressure was noticed.

• Equalizing valves (Hydrogen side) at TE and EE were interchanged, as the exciter en equalizing valve was suspected for its’ malfunctioning but could not see any improvement.

• The impulse tubing emerging from the seal body at exciter end was inspected for probable cracks or looseness, these were found intact and no abnormality noticed.

• The air side oil pressure transmitter and pressure gauge were recalibrated and found OK.

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Since the root cause for the drop in the air side oil pressure could not be found out at site, BHEL HWR suggested exciter side seal dismantling & inspection for probable worn out, damage etc. Turbine was brought to zero speed by stopping the barring gear after cool down of machine. Inspection revealed scoring works on the seal habit on both hydrogen & air side and the sealing was heavy in the hydrogen side. The shaft seal clearance was found and higher side (0.18 to 0.25 & 0.1 to 0.12) than original value in and hydrogen side seal. Scoring works of 0.2 to 0.3mm, deep for a width of max 10mm on the shaft sealing area. NTPC preferred replacement of rotor against BHEL suggestion of inside Generator rotor shaft machining to remove the grove in sealing domain with modified seal suiting the inner shaft seal in dimension. The rotor which was ready for NTPC Kahalgaon project was dispatched for Rihand unit#4 from Hardwar works. Machine was restored & loaded to full capacity. The entry of foreign body in the seal oil damaged to the shaft in the sealing area. However to be on the safer side, seal oil piping is to be acid cleaned and mechanically inspected where ever possible.

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FD FAN 3A (API 26/16) BLADE FAILURE : The unit#3 was taken under shut down for installation of PG test points and minor overhaul in the first week of April 2006 after continuous running at full load for nearly 8 months. The FD Fan was run for more than 8000 hrs. The FD Fan 3A was in service after completion of PG test works. On 20.04.2006 at 15:30 hrs, in unit control room, vibration indication of Fan went high & after that immediately became normal. But the fan was not discharging air. On inspection, it was noticed that the entire aluminum blade (23 n0s) got shaved. Two nos angle iron pieces of approximate length of 100mm were found inside.

It was suspected that left over temporary approach welded on the suction duct during erection, has come out during the course of

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running of fan or some how angle pieces inadvertently crept inside the fan during inspection by O&M and it ultimately damaged the blades.

The blades were replaced with new one available as mandatory spares & the fan was put in service again within 2 days. It is suggested to provide an inspection manhole door in the suction duct & approach platform outside so that engineer can inspect the suction duct before fan is taken into service during initial start & after a shut down job.

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NMEJ’S FAILURES UNIT#3: NMEJ’S FAILURES IN UNIT#3 ATTRIBUTED:

• The product is new to our region. • Erection practice like conventional metallic expansion joint has

caused • Urgency of job for meeting mile stone & missing of certain job. • The off set/orientation documents were not made available at

site during erection. Unlike of metallic expansion joints, this NMEJ is very sensitive to offset, orientation, supports etc. & any deficiency will result in failure.

DEFICIENCY IN SUPPORTS:

• More the requirement of structural/ ducting tolerance is called for, is stringent difficult to achieve.

• The floating sleeve overlap is very less & engineering to review for increasing the same from the present value.

NMEJ failure, the supplier M/s KE–Burgmann investigation report indicating erection error all appear to be due to combination of some likely discrepancies in Engineering, Erection practices, documentation gaps as mentioned below with some examples:

-Tag No. NMEJ 234A (Hot primary air bus duct): Elevation difference occurred at site while load transfer from temporary to permanent supports. Few temporary supports removal was left out. Restraints erection partially completed. The NMEJ failed during the initial running of unit #3 and had to be changed with new fabric.

-Tag No. NMEJ 664A (Mill inlet hot air ducts): Documentation on offset (direction & orientation) was not available. All the 10 nos NMEJs in unit#3 were erected in reverse direction. 2 NMEJs rectified during shut down. Trichy Unit has submitted on site request for unit#4.

-Tag No. NMEJ 224A (Above PAPH): APH to Hot Duct supports provided seems to be inadequate as compared with Tag No. NMEJ 204A, SAPH air outlet where in NMEJ appears to be well supported with 3 tie rod equidistant supports and performance of the same is satisfactory. For NMEJ 224A, site has provided additional support and informed engineering. Both the NMEJs failed during the trial run and patch-up works done for immediate restoring the unit#3. During shut down, fabric & bolster were replaced with newly procured from supplier.

-Tag No. NMEJ 224B, PAPH outlet to Hot Air Bus is erected in inclined position as per drawings. Supplier has provided arrow marking for flow direction and erection considering horizontal position as per design

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input received by him from Trichy Unit. Supplier now informs for inclined/vertical position arrow marking will be in reverse direction. Supplier has suggested modification for this discrepancy by welding an angle 100X100X8 nearest to the duct facing the flow, which will prevent dust disposition during shut down the plant. Same was done during shut down of unit#3.

-Tag No. NMEJ 204D (Secondary air before wind box) thermal movements’ data provided is axial +250, lateral short side 105 & long side 10. For lateral short side provision made by M/s KE-Burgmann is 115, however in actual at site it is going up to 140mm. Design predicted thermal movements and actual at site are in variance resulting in over stretching of fabric.

- BHEL Trichy had wrongly submitted the drawing of thermal insulation for expansion joints applicable for Metallic bellows, accordingly NMEJs insulation for 128 out of 236 nos of unit#3&4 was done as drawing did not indicate type of expansion joints. This mistake was pointed out by the NMEJ’s supplier after the failures of NMEJs. Although insulation was not the reason for NMEJ’s failure, insulation was modified as per supplier’s drawing for the easy accessibility for the maintenance. NTPC also insisted for the rectification of insulation.

BASED ON EXPERIENCE OF UNIT #3, ALL POSSIBLE CARE LIKE FLANGE TO FLANGE DIMENSIONS, FLOW DIRECTIONS, LATERAL MOVEMENTS, ORIENTATION, DUCT ALIGNMENTS (AXIAL, LATERAL), SUPPORTS, INSULATION & CLADING, FABRIC REPAIR IN CASE OF DAMAGE DUE TO WELDING-GAS CUTTING SPARKS/ HANDLING, WERE TAKEN, DURING INSTALLATION OF NMEJs FOR UNIT#4. NO DAMAGES WERE REPORTED IN UNIT#4 DURING LAST 9 MONTHS OF OPERATIONS.

CQA Suggested Corrective, Preventative Measures & feedbacks as under: -Even though Duct FQP addresses permanent supports, releasing of hangers and cold value setting, restraints erection and welding completion need to be separately addressed. Restraint even though a part of support is a new introduction in ducting hence separate address in FQP and communication will prevent likely error. Additional check addressing on ensuring offset of NMEJs is maintained as per direction and orientation during erection (Site to seek clarification on offset requirements in case Engg. drgs. is silent on same). -Separate communication that only after ducts are aligned on permanent supports NMEJ erection is to be taken up. Ducts restraints need completion, ensuring all temporary supports are removed and permanent supports are in place prior to ducts charging (Air, Flue Gas

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as applicable). Also ensure offset requirement i.e. direction and orientation of NMEJ assembly is maintained as per Engineering requirement.

-Engineering to take feedback on likely inadequate supports, variance in predicted v/s actual thermal movements and for vertical as well as for inclined positions of NMEJs flow direction arrow will be in one direction, for horizontal position it will be in opposite direction. Design input to supplier in this regard to be ensured accordingly. Supplier at site on assembly completion provides Arrow marking.

-NMEJ is likely to be part of all power boilers hence awareness workshop at Trichy for site personnel are desired.

-Site feedback is, present tolerances on axial gap ± 5mm, inclined ± 3mm, lateral in one direction ± 3mm, Torsion (Rectangular in longer side) ± 5mm on NMEJ alignment are stringent and need revisit.

-For NMEJ with floating sleeve present overlap is 5mm only, overlap is inadequate without any margin and should be more than the tolerance. Engg. to review and consider at least 10mm overlap.

-Providing thermal expansion diagrams to sites for ducting in line with pressure parts and critical piping being provided now.

-NMEJ’s erection can be done under supervision of Supplier. Supplier scope can include erection supervision at site.

-Bolster (SS Wire mesh + Glass Fabric Insulation Mattress) e.g. NMEJ 234A, 825 mm height, glass fabric for want of intermittent supports, stitching, is settling down. Engineering to look in to this matter. Supplier informs, in Talcher they have provided ceramic felt, where as in Rihand insulation mattresses has been provided as per input from Trichy unit. Talcher NMEJ’s are much lighter & compact in comparison with Rihand site. Difference is due to reduction in fabric layers, ceramic felt.

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BOILER #4 TUBE FAILURE AFTER ACHIEVING FULL LOAD ON 15.02.2006:

REPEATED TUBE FAILURE IN LTSH TERMINAL TUBES (3 TIMES): 18/02/2006 TO 02/03/2006

The unit#4 was operating at around 400MW on 18/02/2006, fluctuations in furnace draft and increase in make up water was observed & subsequently the cause was identified to tube leakage. Load was gradually reduced and unit was tripped.

On opening the manhole door at 65 mtr elevation, tube leakages were observed in the terminal tubes. Boiler was cooled by keeping ID & FD fan running and subsequently inspection was carried out and following tubes were found to be replaced due to primary & secondary damages:

• First tube from SC front wall end in 13th terminal tube assy from RHS.

• First, second & third tube from SC front wall in 14th TT assy from RHS.

• First, second, third & forth tube from SC front wall in 15th TT assy from RHS.

• First & forth tube from SC front wall in 16th TT assy from RHS.

• Sixth tube from SC front wall in 18th TT assy from RHS.

• 15th hanger tube (RHT-9) from RHS.

• 16th hanger tube (RHT-9) from RHS.

• 10th tube of steam cooled front wall from RHS.

• 11th tube of steam cooled front wall from RHS.

All these failures at approximate 70 mtr elevation. The primary failure appears to be rupture of 4th tube from SC front wall in 16th assembly of TT panel. Failure of other tubes was necessitated by steam impingement and subsequent thinning of tube. Moreover 10th tube SC wall from RHS appears to have developed crack.

Dented and bend tubes in TT panel assembly, hanger tube and SC front wall were cut and replaced using mandatory spares from NTPC. Thicknesses of tubes were measured using D-meter and tubes were replaced where tube thickness reduced more than 20% due to steam impingement. A total of 37 joints were welded for repair of above leakages.

On completion of above job on 22/02/2006, the hydro test was carried out at 150 ata and following leakages were observed:

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• 18th tube from RHS in second pass roof near junction header.

• Economizer tube weld joint near Eco-inlet header in LHS.

• Welded bifurcate tube in SC spacer, 3rd SH platen assy from RHS.

• Radiant roof tube 8th SH platen (final) from RHS.

The cracks are found at reducer first connection with pipe, of bifurcate tubes of steam cooled spacer. Immediately SH SCS tube was arranged from Vindhyachal STPP & replaced. Other defective joints were cut & replaced with spool pieces of tubes. On completion of above, again hydro test was carried out. But one more SH SCS tube developed crack at reducer. Hence it was decided to replace all balance 5 tubes by arranging from VSTPP. Finally clearance for boiler light up was given on 02.03.2006. NTPC suspected that cracks in SS may be due to tubes may have come in contact with HCl or chlorine during transportation or at works causing the developing the stress & cracks in SS material.

05/03/2006 TO 08/03/3006:

LTSH terminal tubes leakages:

Primary leakage

• Coil no 15 from RHS – 5th

Secondary leakage

• Coil no 14 from RHS – 4th, 5th, 6th.

• Coil no 15 from RHS – 4th.

• Coil no 16 from RHS – 4th

• Coil no 17 from RHS – 4th

• Hanger tube no 16th.

Total nos of joints – 29 nos including RHS pent house header hand hole cutting joint for baroscopic inspection for any foreign material inside the header or in tubes.

TUBE FAILURES, AFTER COMPLETION (12/04/2006) OF TRIAL RUN OF 30 DAYS CONTINUOUS RUNNING:

13/04/2006 TO 15/04/2006:

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LTSH terminal tube at approximately 70 mtr elevation, coil no 30 from RHS. Possible reason may be due to excessive heat in the zone. The damage tubes and also secondary damaged tubes were removed and replaced with new tubes. Total nos of welded joints – 12 nos.

15/06/2006 TO 18/06/2006:

Water wall goose neck tube (inclined portion at 63 mtr elevation) 1st tube from LHS leaked due to erection weld defect.

18/06/2006 TO 19/06/2006:

SH Screen Tube (10th from RHS) at 65 mtr elevation failed due to parent metal fracture near weld joint.

01/09/2006 TO 03/09/2006:

Hanger tube pin hole leakage from erection joint near front steam cooled wall header.

CQA OBSERVATIONS ON REPEATED DIVISIONAL PANEL TUBE FAILURE:

Failure due to short term overheating & revisiting “Passage Free” check at Trichy Shops, as well as during and after erection at site. At site presently for Headers, Panels Coils and Tubes, air and sponge test cleanliness passage free checks have been envisaged prior to erection (Pre-erection).

After erection no passage free checks have been envisaged. However checks can be addressed before final joints of links are welded with headers. Check for cleanliness of headers & links pipes to ensure no foreign materials are trapped, left inside in advertently. Large dia openings on headers, end caps not in place for a while, foreign material ingress at construction sites cannot be ruled out.

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P.A. FAN 4A - BEARING VIBRATION: Since first commissioning of PA fan bearing (two stage axial blade pitching type) high vibrations were observed when compared to the other fans in unit-3 & 4 & frequent peaks during running. The alignment & tightness of fasteners were found in order, but the problem persists till date. BHEL Ranipet designer visited site in february,06 to study (the behavior) on BHEL site & NTPC request.

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The vibration readings recorded in the fan casing by BHEL Ranipet representative with the instrument (B&K vibro test acceleration sensor 75-065, optical ref. pick up P-95) & the readings in control room of shank supplied by Forbs Marshall probe fixed in the bearing housing is 2 to 3 times higher. Transducer mounting correction for still better contact with base & adjustment of coupling gap to 25mm from 24.5mm as re-commended by Ranipet vibration levels were checked. There was reduction in vibration level, but the control room reading was proportionally high as before. The portable vibration measurement by BHEL Ranipet instrument & customer instrument SRF CM PSK 50 were fairly matching. Even though, Ranipet has cleared the fan for running based on local vibration meter reading. The problem of higher reading at UCB is not resolved which is the basis of operations & maintenance. Moreover, BHEL Ranipet representative informed that BHEL (T) has to resolve this as the vibration monitoring system is ordered by them. Due to appearing of vibration high alarm, customer wants the issue of local reading & control room reading difference to be resolved immediately. Matter is pending with BHEL Trichy. FEED WATER SYSTEM – INPUT SHAFT OF GEAR BOX TDBFP-3B commissioned on 05.06.2005 was in continuous in operation for the last 5 months. On 23.11.2005, it was noticed that the drive turbine rear bearing vibration increased from 22 micron to 40 micron. The gear box vibration (located between drive turbine & booster pump) also increased alarmingly. The gear box was decoupled from drive turbine to check the alignment between turbine & gear box. During this process, it was noticed that input drive shaft of the gear box is damaged ie shaft material is chipped off in triangular shape along the length of the input shaft for a length of 40mm near the coupling hub & keys are dislocated from their position. The gear box was removed from its position. The defective input shaft got sheared off while removing it from gear box by puller. The input shaft already got cracked along the cross section of the shaft.

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It was suspected that the parent material of the input shaft was defective. The supplier’s representative was called to supervise the assembly of the new shaft & investigation of the failure. The machine was made ready in the second week of January 2006.

BOILER HOISTS – CABLE TROLLEYS:

The cable trolleys units associated with mill handling system DSL are breaking down quite frequently which were supplied by M/s Consolidated Hoists. The fabrication of these trolleys is under sized, perhaps suitable for short length tracks where cable pulling load is less. The observations on these cable trolley problems as below: a) The two side cover plate thickness is about 2.5mm, b) The two long distance screw size is about dia 6mm. c) Welding of stud bolt with the power cable holding clamp is inadequate. The total distance of the mill service crane DSL track beam is about 110 m (Rihand is having rear mill combination) and the entire cable-pulling load acts on the nearest trolley to the service crane. Due to less thickness, the cover plates of trolley as well as the distance screws easily get bent, the alignment of the trolley thus get disturbed, open up and disengage from the track beam. As the first one fails, subsequently the supply cable-pulling load comes on the next trolley and one by one they fall down along with the power cable. Since proper reinforcement is not provided on the cable clamp with the stud, the joint fails and the power cable along with cable clamps get detached from the trolley. The commissioning of whole mill handling system could not be done and during initial trials itself a lot of break downs occurred with the DSL trolleys. For ESP transformers handling system (PGMA 78-773), much heavier trolleys were supplied by M/s Power build hoist maker. This is made of channel with 5mm thick plates. Here the track length is almost half (50m long) and that too for pulling much lesser cable size compared to Mill service crane DSL cable. The similar problem may be faced in ECO coil handling system also, long track with same trolleys. At a high elevation (+72m level), repair & frequent maintenance of trolleys in the mid air is very difficult and simply

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unimaginable. The DSL lengths of ID Fan, APH elements handling system are also more and these are also not at lower elevations for easy maintenance. The matter has been referred to Trichy engineering for review of design with the supplier M/s Consolidated Hoists and replacement of all such trolleys and track beams with improved design. The trolleys for ESP & TG side are more rigid & steady, supplied by M/s Herculous & M/s Power Build. The photos of trolleys (both assembly and in knocked down condition) of mill, ESP handling system and other typical system as below:

MILL TROLLEY ASSY MILL TROLLEY CABLE CLAMPS

MILL TROLLEY COMPONENTS

MILL & ESP TROLLEY ESP TROLLEY OTHER TROLLEY

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SUGGESTIONS FOR BOWL MILL IMPROVEMENTS: SL AREA PROBLEMS FACED SITE VIEWS ACTION SUGGESTED 1 Civil It is difficult to arrive at

required elevation of foundation bolt by referring foundation details drawing at the time of casting foundation. Especially with T-type foundation bolt drive motors, serious erection problems will be faced with high elevation mill and low elevation of motor.

Referring Section AA of this fndn details drg, keep only the key dimensions required for civil agency. All other required fabrication & reference dimensions may be transferred to 'Mill fndn fasteners assy' drg. Any miss interpretation / or error by civil agency may render the foundation not usable since in most of the projects the civil work is done by the customer.

Engg may revise the drg to provide the elevations of foundation stud top with respect to zero level and that too with foundation stud fully screwed in to the bottom cover assy. A note in this regard may be given in this drg. After casting there are always chances that the foundation level shrinks considerably and the maximum margin for bringing up the foundation stud after placing the mill drive assy may also be mentioned in drg.

2 Civil Grouting of mounting plate all around is not achievable. Especially, the inner side of mounting plates are being exposed For proper grouting of mounting plate, the grouting shall be done at least 30 mm beyond all sides of mounting plate and to a height, just 7 to 8mm short of mounting plate top.

This is due to the constraint/ restriction of foundation concrete pier width for removal of gear housing cover lower in future maintenance works.

We feel that, with present design the grouting alone may be inadequate without packer plates. HYD to supply cut packers and shims of assorted thickness in future projects for load distribution thru' packers.

3 Lub oil system

Presently there is no provision for ascertaining the quantity of oil flow to Upper radial bearing. Especially during initial commissioning there is apprehension that URB may starve of oil. Moreover, with drastic change of oil density w.r.t oil temp. the adequacy of oil flow thro' the bearing is difficult to ascertain.

Provison of Flow indicator in URB L/O inlet to ensure oil flow and adequacy of quantiy is necessary like BBD Mills

Engg. to include flow meter in future contracts

4 Lub oil system

One flexible hose is provided below LRB oil inlet line. There were instances of hose failures during operation and leakage of large quantity of oil. Variants in hose supplies w.r.t type & quality were also noticed.

In case of emergency isolation of gear box oil reservoir is not possible in absence of any isolation valve. This is also reqd in the event of damages/ replacement of L/O line fittings, flexible hoses, view glass etc

Supply of quality & identical hoses to be ensured. One no. of ball type isolation valve with locking provision to be provided immediately below LRB oil inlet.

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5 Lub oil system

In most of the mills both L/O pumps run as a result of higher set value for pressure low limit for second pump pick up.

There is no uniform procedure avl to set the adjustable orifice for both URB/ LRB oil inlets and it is not measurable from outside. As a result there is variation in pr. Setting Vs. oil temp. from mill to mill.

Provision of flow meter in oil inlet may greatly reduce this problem. Further as a guidance Engg may give comparison chart for the temp. and pressure of oil w.r.t orifice opening.

6 Lub oil system

Unit supply of for L/O piping support matls are not suitable / sufficient. One support rod and one U-type flat clamp for each piping line is envisaged in drawing.

The piping lay-out drg is only indicative and in actual site condition the routing is different. Pipe supports are required at different locations with more no. of clamps.

The support materials for L/O lines such as angles in running lengths, threaded U-rod clamps with nuts corresponding to each pipe size are to be included in drawings and documents.

7 Lub oil system

Site observed supply of glass as well as acrylic sheets for L/O control panel doors. All glass panels were found broken in transit. Even some of the acrylic sheets were also broken.

These sheets were not properly fixed to the door frames. Even if it is properly fixed, due to larger area, these are susceptible to damage transit as well as in actual site conditions.

Window type provision may be provided. Acrylic sheet area to be limited so that only pr. & temp Gauges will be visible. Balance portion shall be made of sheet metal. Acrylic sheets shall be properly fixed preferably by screws.

8 Mill dis-charge valves

Mill discharge valves pneumatic operation and limit switch contact is not reliable in such a dusty region.

To avoid mill trip by accidental closing of flap or to avoid delay in mill start due to non- opening of flap, the MDV flaps are always kept open by locking manually.

With existing isolation provided at furnace end, Engg may review to provide manual butterfly valve which can be manually operated and locked in open/ close position.

9 Mill dis-charge valves

Tapping points for PG test of mills is not being decided during Engg stage.

To provide tapping points at a later date is very difficult after completion of insulation and platform works. This re-work in hostile environment with lot of heat, coal/ ash dust could very well be averted by prior planning during erection stage itself.

Mills and Ducting group should initiate dialogue for future projects w.r.t ducting layout and decide upon the PG test points. Necessary tapping points shall be included in the regular supplies itself.

10 Mill dis-charge valves

The scrapper door approach platform size is inadequate. The only one make shift ladder is very heavy to handle.

The width of the platform is narrow and under sized. The tube sections for platform supports increases work volume at site.

Wider platform may be provided. Instead of pipe sections, standard angles in running length may be provided. The ladder weight may be reduced by simple construction.

11 Mill dis-charge valves

We have noticed a lot of hot air leak associated with fire sparkles around flange joint between hot air inlet duct and MSL body. Mills were withdrawn many times to attend to this problem

MSL body flange at bottom portion has tapped holes with poor quality and the screws are not getting tightened properly. The mating flange provided by ducting group is not thick enough and it tends to warping.

HYD may supply the mating flanges with suitable heat resistant special gasket (glass fiber). Also design may be changed to avoid tapped holes.

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12 Spring The resolution of spring compression pressure gauge is in sufficient.

The supplied pressure gauge dial reads from 0 to 600 Kg/cm2 whereas for 9.5 ton compression only 72 Kg/cm2 pressure is to be applied.

To explore and supply bigger dial (say 10 inch dia) type pressure gauge with maximum pressure range not exceeding 50 to 100% of required setting value.

13 Spring W.r.t spring compression special T&P, two variants of jack, pump & pr. Gauges with different capcities were supplied to Rihand site. Site reported that one set was of under capacity and could not be used.

Under same DESS No. the supplied jacks & pumps are from VANKOS ( 60T cap jack & pump type VH HP2, pr. 500Kg/cm2) and HYDROPAK (lesser capcity jack & pump sl No. 1375)

HYD unit to ensure supplies are made from same party with identical capacity of required rating

14 Spring There is difficulty in tightening or loosening the spring stud lock not with supplied spring pre-load fixture especially after keeping the lock nut keeper inside the fixture.

The fixture cut out portion length is small. During spring pre-loading, after keeping the lock nut keeper, tightening/ loosening of spring stud lock nut is difficult due to less room space.

Engg may study to increase the length of cut-out portion of spring pre-load fixture / length of pre-load fixture

15 Upper radial bearing

During initial period of coal firing, URB temp. high was noticed in several mills.

Site dismantled the scrapper assy, lower skirt and inspection doors in front of the URB RTD termination to find that the insulation packing was inadequate.

Specific Shop Note and check point at works to be ensured for dense insulation packing around inspection doors. This has to be extended beyond the inspection door to the possible extent.

16 Sear air fan

Mismatch of fittings in seal air piping noticed in many projects

The supplies received at site and items shown in erection drg differ putting site into hardship to arrange suitable fittings. Especially the 90 deg. street elbow ( drg 2-61-800-02483) fitting is not applicable.

ENGG to study / revise drg and change specification.

17 Sear air fan

The threaded sockets location in Seal air header to Drive assy is not matching seal air hoses locations / Journal spring housing chambers

Site had to re-route connections to complete the work.

Like in Seal air header to drawing, suitable note may be given to burn the holes in the header and weld the pipes. For header support, cut channels may be provided which had to be welded atleast at three places on MSL body flange.

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18 Classifier Inner cone support assy (60 Deg) welding on to the inner cone pose problems.

The opening area provided between ceramic tiling is not large enough. After locating the pipe, sufficient clearance space is required for welding say, 25 to 30mm beyond pipe OD considering tiles thickness, accessibility of welding electrode and also to avoid cracks on tiles due to welding heat.

Engg to make necessary changes in inner cone drg.

19 Coupling The coupling dimensions while site checks pose problems.

The dimensions provided in Field Quality plan and actual supplies differ. This pose problems in filling up shaft ends and coupling bore dimensions in FQA log sheets.

HYD to discard dimensions in FQA log sheets and make columns blank. The coupling MFR / Supplier drgs shall be made avl to site as a erection drg to enable filling up dimensions. Worm shaft end dimensions may be provided in GA drg.

20 Cooling water

The view glass in CW line broke very frequently

Site had to provide dummies on the Cross. This view glass is redundant since Piping centre/ Chennai already provides Flow indicator in CW lines

These cross and view glass may be discarded

21 Cooling water

Mismatch of fittings in CW piping noticed in many projects

Ref to drg 1-61-188-01037 - Oil cooler piping assy. 1" pipe nipples are irrelevant. Site had to arrange suitable nipples to complete the work. Moreover the CW hoses are supplied with one loose union at one end. This requires male nipple with taper edge to suit the spherical seat of hose union otherwise which CW will leak.

ENGG to study / revise drg and change specification. Site suggests, since at HYD Works, CW inlets branching is made from common pipe in each cooler, all supply and return fittings may be rationalized to 1 1/2" size with 1 1/2" globe valve at inlet.

22 Drive assy

Site observed leaks in Oil cooler manifold flanges. Commissioning spares of gaskets were not matching the flanges especially in partition ribs.

Though it is not mentioned in HYD engg documents, site normally carries out hydro test of all coolers during course of erection and this leakage was observed in several mills.

Check points in shop floor may be ensured. To ascertain healthiness of coolers after transport, for site checks, engg may include hydro test pressure in erection drawing.

23 Drive assy

The tapped holes on mill drive assy for return oil and drain pipe (3") is not properly done at works.

In complete threads cutting were observed in some mills. In earlier cases (883 Mills) wherein heater provision was given, there also incomplete threads were noticed and site faced difficulty in fixing heaters.

Shop checks may be ensured. Alternatively, design may review provision of boss face with 6 or 8 tapped holes for M16/M20 screws and flanged pipe instead of 3" tapped hole.

24 Journal head assy

Instances of wrong assembly of Journal Head inserts were noticed.

Site corrected by repositioning these inserts.

TOP and Arrow marks may be punched on these inserts and drg may be revised to incorporate this requirement so that this error can be eliminated in shop assembly.

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25 Journal head assy

The problem of air seal ring upper assy has become a routine. The variation in dimensions of air seal ring upper part is more. Sufficient quantity of shim sets are also not envisaged. There is no commissioning spare.

In some cases even without shim sets, zero clearances were observed. At site the air seal ring flange thickness was reduced machining. In many cases a large amount of shims were required to obtain the required seal air clearance of 1mm.

Engg may include a few more shim sets as commissioning spares. Seal ring dimensions have to be ensured. The tolerances on journal head taper bores and relative plane dispositions of taper bores with flange surface may be also reviewed which may contribute to this problem.

26 Journal opening cover

JOC Hinge clamps provision pose problems

In some of the JOC bodies, the tapped holes (M24) were not provided from works. And in some cases the tapped holes are not matching with clamps holes while assembling.

We doubt this arrangement is not made use of by O&M personnel. HYD may review to discard this arrgt.

27 Journal stop bolt

The spanner for journal stop bolt is not being supplied in special T&P.

Erecn & O&M manual shows only plain spanner which is also not suitable.

In practice, heavy duty ring spanner ( hammering type ) is required. Engg to include this sub-dely item in future projects

28 Journal stop bolt

Journal stop bolt hexagon faces are not suiting standard ring spanners

Site had to grind off the hexagon faces to match standard 75mm spanner

Engg to study and revise the dimensions of A/F and A/C of the hexagon portion.

29 Journal stop bolt

Journal stop bolt locking items supplied by HYD is not suitable.

The female hexagon part is under sized, improperly fabricated (gas cut ?) and quality is poor. Even if this arrgt is properly fabricated, this locking arrgt will not work out for all positions of journal stop bolt

Engg to design a better locking arrangement.

30 Mill reject

Instances of rejects choking in tramp iron duct passage occurred

The tramp iron duct end flange (terminal point) is in vertical plane and flange width is not wider. This necessitates 1) the connecting ( by Mill reject package supplier's) duct has to have some horizontal portion and 2) due to limited flange width and bolt holes, the duct opening size has to be contained within the HYD's tramp iron duct opening. This leads to entrapment of some small foreign matls on conn. Flanges region and later choking starts.

Engg may review changes in tramp iron terminal flange design. Instead of vertical plane, it can be provided at right angles to the duct axis. This will enable conn. duct in the same slope and conn. bolts will not foul. To enable bigger size conn. duct, HYD may widen the flange and the bolt holes shall be shifted towards edges.

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TRIAL RUN OPERATION: As per contract, the trial run operation of the complete facility as an integral unit is to be conducted for 720 continuous hrs. During the period of trial run operation of 720 hrs, the unit to operate continuously at full rated load for a period not less than 72 hrs. & generate a minimum of 342 million KWH as measured at generator terminals. Any loss of generation due to constraints attributable to the employer shall be construed as deemed generation. In case the generation loss on account of deemed generation is more than 18 million KWH, the duration of the test shall be extended accordingly. UNIT#3: The full load of 500MW achieved on 19.06.2005 and decided to start the trial run operation from first week of July 2005, but unit is to be tripped due to various reasons like bottom ash chocking, condenser tube leakages, GT failure, CEP problems, NMEJ failures, boiler tube leakages etc. Finally trial operation could be started on 10.09.2005 and completed after 30 days on 09.10.2005. The unit was tripped 28 times from the first synchronization to trial operation completion. The details are indicated as below:

UNIT#3 TRIPPING DETAILS (Up to Trial run completion)

Sl No Syn Date Tripping Remarks 1 1822 26/01/2005 1833 26/01/2005 - Synchronization on oil firing 2 2324 30/01/2005 1858 31/01/2005 - Synchronized for CMD/NTPC visit and tripped for

pending works. 3 0740 29/04/2005 1700 29/04/2005 - Boiler light up on 27.03.2005 with coal firing.

- Boiler tripped on 28.03.2005 due to heavy damages in CRH line (Hammering due to mal functioning of HP bypass valve). - Boiler light up on 25.04.2005 after CRH line rectification. - Synchronized on coal firing. - Generator tripped on LFP protn due to closing of Control valves. EHTC hashes observed in pri DPU, Sec was not getting reset from HMI or at DPU reset switch. - Power supply of top rack of EHTC was Switched off.

4 2122 30/04/2005 0242 01/05/2005 -Class B protection, due to cond VSP. 5 0624 01/05/2005 0715 01/05/2005 -Class B protection, due to cond VSP. 6 10.42 01/05/2005 1234 01/05/2005 -Class B protection, due to cond VSP. VSP

protection bypassed which is agreed by BHEL. 7 1503 01/05/2005 2303 01/05/2005 -Turbine lub oil pressure low, operators trained to

change the oil filters 8 0200 02/05/2005 1647 02/05/2005 - MD BFP trip on calculate flow speed vs actual flow

> 50 TPH, strainer got choked & flow fluctuation, strainer cleaned properly.

9 0200 03/05/2005 0913 05/05/2005 - Furnace pressure very low, running feeder A tripped. Feeder auto response & furnace pressure auto response made OK.

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10 1500 05/05/2005 1510 06/05/2005 -EHTC got unloaded without any reasons and gen tripped on Low forward power protn. EHTC output change over from load to speed control with in 2 sec to 183 mw remains 2 sec. Speed controller O/P came to 21% , L/C to 20 %. EHTC problem. -IP oil pr was steady. Load changed from 128 MW to 183 MW. IP & HP control valve went to zero position. Secondary oil pr was steady. -EHTC- Unstable Logic Control (LCUL) malfunctioned. One modification is done. PRTD >300MW is also added in LCVL.

11 2100 06/05/2005 2240 07/05/2005 - Condenser vacuum low, due to TDBFP exhaust line diaphragm ruptured. - TD BFP-A rolling was done with exhaust valve closed and diaphragm got ruptured. As soon as exhaust v/v opened, condenser low vacuum appeared. - Exhaust valve status is now used as permissive and tripping.

12 0041 08/05/2005 1805 08/05/2005 - Partial flame failure. Boiler Flame failure took place when load achieved 240 MW. - 7 oil guns are in service , 4 mills at 40 TPH HOTV got closed on pr low (4 ksc ) interlock as oil strainer got choked. Boiler could not sustain on coal flame. - Mill loading was low and pr loss cause flame failure. Oil strainer was cleaned.

13 2354 08/05/2005 1709 10/05/2005 - Unit shut down was taken for Gen Bearing no 6 high temp. - 24 hour before brg temp had risen 75 to 95 deg C in 15 min. - Problem found in O ring cord in Brg 6. Brg 6 replaced. O ring removed & bearing replaced.

14 1310 30/05/2005 2333 01/06/2005 - PA fan 3A was in auto at 75 % (hdr pr 835mmwc). PA -B was in manual and got tripped , PA A forced to 65 % after 6 sec. PA Header pr low (<625mm) in 5 sec caused loss of primary air to all mill. After 9 sec fur pr low (-100mm) and after 1 sec blr trip on fur pr V low (-175mm) appeared. No C&I problem and happened due to stalling of fan. - PA-B brg temp actual went high, 10 min past v. high appeared to trip by logic. If both PA fans running and one trips Other blade pitch forced to 65%. - 65% Forced made to 85%.

15 0205 02/06/2005 0439 02/06/2005 - All HFO C pump tripped as control fuse had blown and unit tripped on flame failure at 240 MW load. - Fuse replaced and elect. Power restored.

16 0859 02/06/2005 1758 03/06/2005 - Tripped on Furnace pr low on tripping PA fan 3A due to motor DE vibn. PA-A vibration occurred furiously. - Vibration went high as some work was going on near local.

17 2048 03/06/2005 0031 04/06/2005 - Generator overall differential protn appeared. - UAT CT polarity was reverse. - Elect. Checking was done and been corrected.

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18 1804 04/06/2005 0702 09/06/2005 - Tripped on Furnace pr low on tripping PA fan 3B due to motor wdg temp. high(instrumentation problem). Unit load 460 mw & PA hdr pr 830 mm. PA-3B Y winding temp went high in 1.5 mins. Wire tightness checked. - PA -B tripped and after 5.5 sec PA hdr pr low (625mm), 0.5 s PA hdr V low (500mm)Both PA were at auto at 40% and on tripping PA-B demand of PA-A forced to 80% (earlier 60 % changed to 80%) but blade pitch took 20 s to reach from 40 to 80% (Mech delay, Total Travel time 65 s). All FDR tripped and Blr tripped. - Winding temp has been bypassed as per OS/Engg recommendation.

19 2046 09/06/2005 1214 11/06/2005 - S/D due to non availability of two CEPs. - CEP C Thrust Brg got damaged. And Replaced on 14/06/05. CEP-A pump got Jammed. Replaced from U#4. - Thrust Brg replaced.

20 0506 18/06/2005 0058 22/06/2005 - PA fan 3B tripped on differential protection. Tripped on electrical power supply interruption of UT change over to station. - Problem in PA B motor internal lead.

21 0506 22/06/2005 2206 28/06/2005 - S/D Due to Bottom ash choking & slagging . Shut down contd as 29 th June report of DGA 20 ppm acetylene of B phase GT. - Big clinker trapped. GT-B phase oil got emulsified. - Bottom ash cleaned. GT B-phase transformer replaced.

22 0541 13/07/2005 1330 18/07/2005 - Strainer of both CEP A&C got chocked and CEP B also tripped on discharge pr. Less than 18 ksc. Boiler was hand tripped. - D/A level control taken on manual and reduced to 50%. - Strainers cleaned.

23 1209 19/07/2005 0838 30/07/2005 - Boiler trip due to drum level very low. - BCW pump emergency push button operated C&I fault. - Condenser tube leakage arrested.

24 1901 03/08/2005 1121 04/08/2005 - S/D due to PA hot air NMEJ leakage. - NMEJ replaced.

25 0201 06/08/2005 1536 24/08/2005 - S/D due to PAPH- A & B outlet hot air NMEJ leakage (224A). - NMEJ repaired.

26 1746 26/08/2005 0548 28/08/2005 - S/D due to Boiler tube leakages. - Boiler tubes leakages attended.

27 0522 09/09/2005 1124 16/09/2005 - Tripping due to PA fan – Brg vibration high. - False alarm – C&I check.

28 1440 16/09/2005 28/12/2005 - Tripping due to clinker formation in the boiler.

TRIAL RUN COMPLETION ON 09.10.2005 29 01/01/2006 31/03/2006 TRIPPED FOR PREPRATION OF PG TEST.

UNIT#4: The full load of 500MW achieved on 15.02.2006 and decided to start the trial run operation immediately. The LTSH tube leakages occurred and trial run could be started by 14.03.2006 and completed by 12.04.2006. Unlike Unit#3, very few problems faced in unit#4. The tripping also was reduced to only 8 times from the first

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synchronization to trial operation completion. The details are indicated as below:

UNIT#4 TRIPPING DETAILS (Up to Trial run completion)

Sl No Syn Date Tripping Remarks 1 0414 24/09/2005 0440 24/09/2005 - Synchronization on oil firing 2 0159 05/12/2005 1035 06/12/2005 -Synchronized on coal firing.

- Tripped due to abnormal sound observed from FD fan 4A, cause not deducted.

3 2205 06/12/2005 0443 07/12/2005 - Tripped on condensate pressure flow low while normalizing of CEP & air locking occurred in the running CEP.

4 1045 07/12/2005 1428 07/12/2005 - Unit shut down taken for H2 seal leakage. 5 1749 27/12/2005 2310 27/12/2005 - Boiler light up on 26/12/2005, but tripped on

27/12/2005. - Generator EE side seal oil DP was reduced while increasing the load and unit tripped. - Generator rotor replaced.

6 1644 04/02/2006 1305 07/02/2006 - BLU on 01/02/2006 night. - HRH safety valve floating (1 nos) on 03/02/2006 early morning hrs. - Drum level safety valve floating (2 nos) on 03/02/2006 day time. - Rolling and synchronization of turbine on 04/02/2006 day time. - Coal firing with 1/2 mills on 05/02/2006 - 5 mills in service load up to 205MW - CEP-A motor problem (one phase dead) replacement started on 03/02/2006 and completed on 06/02/2006. - All CEPs tripped due to wrong operation of valves at 13.00 hrs 07.02.2006 and taken back immediately. - CEP-C motor bearing problem - Dismantling on 08/02/2006, rectified on 10/02/2006 - TD BFP Problem, Re-circulation valve yoke, Wrong erection of NRV, Servo-motor rectification. -Unit tripped on RH protection, on normalization of CEP, running CEP tripped due to air locking, while reduction of load HPCVs sensed Zero even in 10% position.

7 1932 07/02/2006 0838 18/02/2006 - Mill no 8 (6th) clearance given on 14.02.2006 and taken into service on 15.02.2006 - Full load of 500MW at 08.04PM on 15.02.2006 with 6 mills & oil supports, 7th mill made available on 17.02.2006. - Machine tripped due to boiler tube failure in LTSH terminal tubes & steam cooled SS tubes at 0838 AM 18.02.2006

8 0528 02/03/2006 1100 05/03/2006 - Machine tripped due to boiler tube failure in LTSH terminal tubes.

9 1903 08/03/2006 0301 13/04/2006 - Machine tripped due to boiler tube failure in LTSH terminal tubes.

TRIAL OPERATION COMPLETED ON 12/04/2006 10 0420 15/04/2006 0535 15/04/2006 - Fire near turbine front pedestal. Machine hand

tripped. - Vapor separator mesh cleaning done.

11 0919 15/04/2006

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DELAY ANALYSIS: As per contract, the unit#3&4 were to be commissioned on coal firing by 13.03.2005 & 13.08.2005, but it was not possible to commission on coal firing due to delayed bunker floors. First synchronization was done by oil firing on 26.01.2005 & 24.09.2005. The trial run operation was completed on 09.10.2005 & 12.04.2006 against the contractual dates of 13.06.2005 & 13.11.2005 of unit#3 & 4 respectively. The reasons for the delays are analyzed as below: UPTO TRIAL RUN COMPLETION: BOILER PACKAGE: The boiler is always in critical path. Any delay in civil fronts, material supplies or equipment failure delays the project. MATERIAL SUPPLY (TRICHY):

The diverter & flap dampers, which are essential for boiler light up & coal firing respectively, were delayed by more than 6 months in both the units. The ducts were to be dummied for the light ups, it only increased lot of re-work. The rear arch tubes (PG 07), matching piece (P-91) of MS line in unit#4 got delayed by 9-11 months, required for the hydro test. RH front platen coils (PG 16) for unit#4 got delayed by more than 12 months, required for full hydro test. Hot air gates and air receiver (3 nos) for unit#4 received 14-15 months late, must for the sustained load of the machine. CIVIL FRONTS (NTPC): - The bunker floors & bunkers for both the units were delayed by 18 to 24 months, which are required for erection of RC feeder and start of coal piping from mill end. This was a cause for delay in coal firing. BHEL had taken advance action by erecting the mills before casting of bunker floors. Erection of RC feeders & coal piping were carried out on war-footing immediately after availability of fronts to minimize the delay of coal firing and full load. - The flooring around the boiler and approach was always a problem. NTPC started flooring, drains & road works only in the end of project. During raining seasons, material feeding & crane movements were very difficult due to water logging and slushy earth.

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- Fan foundations were also made available late by more than 6 months than L2, but it did not affect the schedule of project. FAILURE OF EQUIPMENTS: UNIT#3: CRH line water hammering, Generator transformer failure, Rubber cord at generator exciter end bearing, NMEJs failures, Hot air gates, Ash/ clinker accumulation in hoppers etc delayed in coal firing & trial run completion of Unit#3. UNIT#4: High final CRO values of turbine, Generator seal oil DP problem, Boiler tube leakages, etc. caused delay in coal firing & trial run completion of unit#4. OBSTRUCTIONS FROM CIVIL AGENCIES: As the NTPC – Civil agencies delayed the bunkers, its structure and flooring works around the boiler, lot of obstructions were in carried out the boiler erections particularly unit#4. Civil agency was also using high reach crane for bunker erection, thus obstructing the movements of BHEL cranes & materials. In Unit#4, BHEL have to stop the erection activities between boiler & bunker bay to facilitate civil agency to complete the bunker bays.

BHEL has to shift the materials several times to facilitate the civil agency complete the flooring works. The coordination with civil agency was very difficult. ASH SLURRY PIPE LINES LAYOUT: Ash slurry pipe lines of unit#3 are going through unit#4 and over ground, has restricted the movements of high reach cranes, hence cranes are to be de-mobilized and balance erection of approximate 4000MT were carried out with only electrical winches in unit#4. It has taken a longer time. CABLE & PIPE TRESTLES: The layout of the plant is such that pipe & cable trestles are going on both sides of boiler with an assumption that LHS drives cables are to be routed through LHS trestle & vice versa so that in case of any fire/ failure on either side, will not affect other side drives and unit can run at least at 50% load. Secondly NTPC did not allow the underground power cabling of ID fans for faster restoration in case of cable failure in future. All the HT/LT power & control cables of Mills, ID fan & other drives and ESP are going through these trestles; hence it was essential to erect the trestle before light up of boiler. It restricted the movements of the cranes. All the primary air ducting for mills is to be done with electrical winches as mills are installed in the rear side of boiler.

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LABOUR PROBLEMS: The site has faced labour problem in the initial stage of Boiler#3 erection and all the workers of M/s TPL agency had to be retrenched for smooth working. After completion of trial run also, both the boiler agencies experienced the labour problem. The workers slowed down work for almost 3 months and hence all the workers are to be retrenched and new manpower were to be deployed. This is peculiar problem faced in the end of the projects. TG & ELECTRICAL PACKAGES: Although civil fronts (TG deck approach, whether proof TG hall, Cable vault, HT/LT/MCC switch gear rooms, Transformer foundations, pump foundations etc) and material supplies like IP turbine & generator got delayed by more than 9 months, but TG & electrical readiness matched with the boiler as lot of float is available in these areas. But last minute TG equipment failures particularly in unit#4 contributed delays in completion of trial run operation. COMPLETION OF FACILITIES: BOILER: SUPPLIES FROM TRICHY; Floor grills & hand rail materials (350MT) got delayed abnormally by more than 24 months due to mismatch in drawing & shipping list quantities. These items were received up to December 2006. As numbers of project are in hand, manufacturing unit does not pay attention for the completion of such last supplies of design mistakes. Site has to struggle for the items required for attending the equipment failures or received in damaged condition. Manufacturing unit wash off their hands in case of equipment failures, shortage or damage due to any reason once the supply is made. INCREASE IN TONNAGE; Initially 33100 MT envisaged per boiler & accordingly boiler erection agencies were issued the contract. Later on it was increased to 35600 MT per boiler, hence erection of boiler with additional 2500 MT in a contract stipulated period of 37 months became very difficult & contract period of erection agencies were to be extended. ELEVATOTS; BHEL Trichy awarded the supply & erection contract to M/s Kone elevators. The delay in civil works for machine rooms & pit by NTPC, coupled with poor mobilization by the elevator erection agency, elevator erections are the last activities of the site (likely completion by March 2007). The agency could not deploy the manpower for parallel works of lift. FLUE GAS CONDITIOING SKID; these are being installed first time in India by M/s Bachmann India Ltd through BHEL Ranipet for SOX

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control & increase in efficiency of ESP. Its engineering clearance took lot of time and supplies could start only in July 2006 & erection in mid September 2006. The FGCS commissioning is possible only in January 2007. EQUIPMENT HANDLING SYSTEM: Repeated failure of DSL trolley, during commissioning of handling system, the handing over of system delayed. PEM SUPPLIES: CABLING: Due to wrong estimation of cables, 24 Kms of cables of various sizes were found short in the last stage. PEM had delayed abnormally in ordering the cables; PO could be placed only in the last week of November 2006. The cabling works of hoists, ETP boiler blow down pumps, gate/ damper blowers, welding sockets & air conditioning equipments in service building etc are held up for long time. Cables likely to be received only in January 2007. LT MODULES: PEM wrongly estimated the capacity of LT modules; hence no module was available for gates/ damper blowers & hoists in boiler, which are possible to be installed only in January 2007 by supplier M/s Control & Switch Gear. STATION LIGHTING: Delay in receipt of hand rail posts of boiler#4 & late civil fronts of service building resulted in late completion of lighting works. FIRE SEALING OF CABLE ENTRY: The engineering coupled with ordering delay, first lot of fire sealing material was received only in December 2006 & work could be started only in the third week of Dec’06. All the entry points could not be taken up immediately, only selective points were released as 22 Km cables are yet to be received. MISCELLANOUS HOISTS & OFFSITE EOTs: Due to change in vendor, the supplies of these systems were considerably delayed and also coupled with late availability of civil fronts, erection agencies demobilized the site. We have to pursue with agency for re-mobilization in December 2006 & complete the works. MISCELLANEOUS STRUCTURE: As per contract, BHEL has to carry out the pipe/cable trestles/racks and platforms within the battery limit of main plant. The poor engineering and delayed steel supplies from SAIL & floor grills/ hand rail materials by erection agency, the package completion & handing over remained the problem up to the last. EFFLUENT TREATMENT PLANT (ETP): The engineering clearance of ETP given only in March 2006, then only civil works & supplies started. Site also faced the labor problem during execution of ETP. The package could be commissioned only in November 2006 and stabilization & trial run will be completed by February 2007.

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SERVICE BUILDING: NTPC started civil works of service building very late & partly fronts for erection of AC equipment, cabling given only in March 2006 with a delay of 24 months and subsequently fronts for station lighting & elevators were released up to October 2006. The delay of service building affected the works of four agencies - air conditioning, cabling, station lighting & elevators. PG TEST: BOILER; could not be started as boiler parameters are not matching with the contract conditions. The SH/RH spray could not be made within contract values and several discussions with NTPC could not yield any result. BHEL Trichy yet to prove the PG test of 500MW boiler at NTPC sites like Vindhyachal-stage-II, Simhadari, Talcher, Ramagundam-stage-III. TG; Initially NTPC was not agreeing for the concession of SH/ RH spray for TG – PG test, after lot of discussions NTPC agreed, but delayed the PG test. These could be carried out in October 2006 & December 2006 for unit#3 & 4 respectively. OTHER EQUIPEMENTS; The PG test for Condenser polishing unit (CPU), Mill reject system (MRS), Plate heat exchanger, Compressed air system, Pumps (CEP & BFP), HP heaters, Fire protection system, were completed up to December 2006. Effluent treatment plants (ETP), Mills, COLT, ventilation, etc are likely to be completed by February 2007. Air conditioning PG test monsoon completed in October 2006 & summer planned in April/ May 2007.

CIVIL INPUT FROM CUSTOMER L1/L2 vs. ACTUAL (Unit#3) Sl no Civil input months as per

L1/L2 Actual Delay

in civil fronts

in months

REMARKS

1 11 KV Power Supply from Customer

6 13/02/2002 13/02/2002 -

2 Foundation for Boiler Col.

10 13/06/2002 30/07/2002 1.5

3 Availability of Crane Girder

16 13/12/2002 11/02/2003 2.0 without approach and platforms. Load test completed on 19.06.2003, but DSL could be charged only on 22.07.2004 after completion of NTPC civil works above the DSL.

4 Foundation for ESP Col.

16 13/12/2002 30/12/2002 0.5 First pass on 28.10.2002 and in phased manner by 30.12.2002

5 Civil front for Switch yard for start-up power

18 13/02/2003 13/02/2003 - Ready

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6 TG Deck with Approach

20 13/04/2003 12/07/2003 3.0 Foundation was handed over on 07.08.2003 after checking, but approach was given on 12/07/2004.

7 Control Room Readiness(For Ern.of AC Ducting)

21 13/05/2003 01/09/2003 3.5

8 Availability of Battery

Room 21 13/05/2003 05/02/2004 9.0 Doors were fixed in

June 2004 9 HT SWGR Room

Readiness 21 13/05/2003 13/01/2004 8.0 Doors/ windows fixed

much later. 10 Front for Cable Tray

Ern (sprdr room) 22 13/06/2003 23/12/2003 6.0 cable vault below HT

switch gear room on 23/12/2003, below 13.5 mtr on 15/02/2004, trestle for CW pump house on 28/05/2004.

11 Readiness of Switchyard control room bldg.

23 13/07/2003 13/07/2003 - Existing Switch yard control room building being used.

12 TG Deck with Weather proofing.

23 13/07/2003 22/07/2004 12.0 On 22.07.2004 civil/ sheeting work completed & permission given for DSL charging.

13 Availability of Trfr & B duct fdn for start-up power

23 13/07/2003 30/03/2004 8.5 Only 80mva transformer fdn was given on 31.10.2003 for placement of Tfr, other Fdns were given in phased manner up to May 2004.

14 LT SWGR room Readiness

23 13/07/2003 04/03/2004 8.0 Civil debris removal, doors/ windows, painting provided in phased manner up to July 2004

15 400 KV Line ( Already Available )

24 13/08/2003 13/08/2003 -

16 Readiness of Mill Bay with mill fdn.

24 13/08/2003 May 2005 21.0 Mill foundation handing over started on 06.11.2003 & completed by 22.12.2003, only one bunker handed over in Jan 2005. Balance progressively by May 2005.

17 Availability of Fdn. for Fire fighting (Pump)

24 13/08/2003 05/05/2004 9.0 Front for Tfr, MCC panel was given in Aug 2004.

18 Compressor Air building & fdn.

25 13/09/2003 25/01/2004 4.0 only compressor fdns were given on 25.01.2004. Other works like removal of debris, side covering, plastering, painting, trenches for pipes/ cables, electrical rooms like PLC, MCC etc were given in phased manner upto

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August 2004.

19 Control Room with catwalk for panel erection.

25 13/09/2003 12/04/2004 7.0

20 Fdn. for Both ID & FD

fans with lub oil pump fdn.

25 to 27 13/11/2003 13/02/2004 3.0 FD/PA 3a - 02/12/2003, 3b - 13/02/2004, ID 3a - 23/12/2003, 3b - 12/01/2004 lub oil fdns were given in June 2004

21 Foundation for Dearetor

26 13/10/2003 12/02/2004 4.0 approach was given much later.

22 Availability of civil fdn. & room for AC Equipments.

26 13/10/2003 09/02/2004 4.0 MCC/ PLC fronts, trenches, plastering, doors were provided up to June 2004

23 ESP control room for AC ducting

27 13/11/2003 April 2004 4.0 AC ducting - 22.04.2004, Ventilation - 28.07.2004, AHU - 08.06.2004

24 Foundation of MDBFP 27 13/11/2003 29/12/2003 1.5 Floor around MD-BFP provided in July 2004

25 Fdn & room availability for DG set

27 13/11/2003 December 2004

12.0 One fdn is made ready on 22.09.2004 & other in Dec 2004, stack fdns are made available in Nov 2004.

26 Fdn. For col.near ID fan & from ID to chimney

27 13/11/2003 30/12/2003 1.5 Fdn started handing over from 15.07.2003. R&Ra fdns on 03.03.2004

27 Readiness of Fuel oil Pump House

28 13/12/2003 05/05/2004 5.0 Fuel oil pump fdns made ready.

28 DM Water by Customer

29 13/01/2004 - Temporarily water is given from stage-I

29 Foundation for TDBFP 29 13/01/2004 25/02/2004 1.5 Second fdn on 2 June 2004

30 Readiness of ESP Control Room with cat walk

29 13/01/2004 March 2004 1.5 Front for panel erection.

31 Fdn. For PA fans with Lub oil pump fdn.

29 13/01/2004 13/02/2004 1.0 Fdns handing over started from 02.12.2003 (PA fan 3A).Lub oil fdns were given in June 2004

32 Chimney for Duct Connection

30 13/02/2004 21/06/2004 4.0

33 Fuel: Oil by Customer 34 13/06/2004 24/09/2004 - LDO availability on 24.09.2004. HFO is available from exiting unit.

34 Ash Handling system for BLU

35 13/07/2004 - Matched with light up of boiler, but with lot of problems.

35 Coal handling system by Customer

39 13/11/2004 available - Provided by March end.

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36 Power evacuation by Customer

39 13/11/2004 available - Matched with the synchronization on 26.01.2005

37 Ash Dyke by Customer

39 13/11/2004 ? - alternate arrangement made

OTHER CIVIL

FRONTS:

1 MOT/ oil cooler/ Oil

canal 08/09/2003 30/05/2004 8.5 MOT/ oil cooler on

27.12.2003, Duplex filter on 27.01.2004 & Oil canal on 30/5/2004.

2 Ventilation 31/03/2003 September 2004

17.0 Ventilation duct front on 01/11/2004, air washer at 8.5 mtr on 16/7/2004, 24 mtr on 10/9/2004.

3 IP bus duct 15/03/2004 31/08/2004 5.5 After Fdn modification on 02.09.2004 and floor at 8.5mtr below generator on 06.09.2004

4 Fire fighting front for pipe erection in CD bay

31/05/2003 07/11/2003 5.5

5 Elevators 13/11/2003 September

2006 34.0

In Service Building. 6 Mill reject system 28/02/2004 January

2005 10.0 Fronts (partly) in Jan

2005 for unit#3, WATER LOGGING PROBLEM IN THE TRENCH PERSISTED FOR QUITE LONG TIME.

7 ETP 01/03/2004 March 2006 24.0 Engineering delays. 8 Service building 13/11/2003 March 2006

to Dec' 06 30.0 Erection works of AC,

elevator, lighting, fire fighting and electrical works.

CIVIL INPUT FROM CUSTOMER L1/L2 vs. ACTUAL (Unit#4)

Sl no Civil input Months as per L1/L2

Actual

Delay in civil fronts

in months

REMARKS

1 11 KV Power Supply from Customer

12 13/08/2002 available -

2 Foundation for Boiler Col.

16 13/12/2002 03/02/2003 1.5

Page 97 of 175

3 Availability of Crane Girder

22 13/06/2003 12/12/2003 6.0 Surge girders were not fixed, 20 to 30 mm bow in the girder no 59-60 & 61-62 in A row. Crane ready for load test on 15.01.2004, but could be carried out on 23.03.2004 as structure was not ready. DSL could be charged only on 09.01.2005 after completion of civil works.

4 Foundation for ESP Col.

22 13/06/2003 27/03/2003 - other fdns handed over up to May 2003

5 Civil front for Switch yard for start-up power

24 13/08/2003 n/a -

6 TG Deck with Approach

26 13/10/2003 23/02/2004 4.0 TG deck approach was provided much later. A make shift arrangement for approach made by us.

7 Control Room Readiness(For Ern. of AC Ducting)

27 13/11/2003 n/a - common for both units

8 Availability of Battery Room

27 13/11/2003 15/07/2004 8.0

9 HT SWGR Room Readiness

27 13/11/2003 30/08/2004 9.5 side covering/ plastering/ painting/ doors/ windows much later.

10 Front for Cable Tray ern (sprdr room)

28 13/12/2003 30/08/2004 8.5 Cable vault below HT switch gear room.

11 Readiness of Switchyard control room bldg.

29 13/01/2004 n/a - Existing control room bldg is being used.

12 TG Deck with Weather proofing.

29 13/01/2004 August 2005 ? The side covering is done in August 2005, but water leaking problem resolved in the end.

13 Availability of Trfr & B duct fdn for start-up power

29 13/01/2004 December 2004

11.0

14 LT SWGR room Readiness

29 13/01/2004 19/07/2004 6.0 Civil debris removal, painting/ windows/ doors provided much later.

15 400 KV Line (Already Available )

30 13/02/2004 available -

16 Readiness of Mill Bay with mill fdn.

30 13/02/2004 February 2006

24.0 Mill foundation handing over started on 24.12.2003 & completed by 15.03.2004, bunker bay started 17.07.2005 with one bunker of LHS & progressively completed by February 2006.

17 Availability of Fdn.for Fire fighting (Pump)

30 13/02/2004 n/a - common for both units

Page 98 of 175

18 Compressor Air building & fdn.

31 13/03/2004 n/a - common for both units

19 Control Room with catwalk for panel erection.

31 13/03/2004 n/a - common for both units

20 Fdn. for Both ID & FD fans with lub oil pump fdn.

31 to 33 13/05/2004 December 2004

7.0 FD/PA 4a - 13/05/2004, 4b - 12/08/2004, ID fdns - 12/04 after completing the lub oil fdns.

21 Foundation for Dearator

32 13/04/2004 23/11/2004 7.0 The foundation casted on 23/10/2004, but handed over after fdn rectification on 23/11/2004

22 Availability of civil fdn. & room for AC Equipment.

32 13/04/2004 n/a - common for both units

23 ESP control room for AC ducting

33 13/05/2004 March 2005 10.0

24 Foundation of MDBFP 33 13/05/2004 04/08/2004 3.0 casted on 21.07.2004

25 Fdn & room availability for DG set

33 13/05/2004 March 2005 10.0

26 Fdn. For col. near ID fan & from ID to chimney

33 13/05/2004 19/05/2004 - Y&Z row Fdns handed over on 19.05.2004, others in phased manner up to July 2004. Area is leveled in Aug 2005

27 Readiness of Fuel oil Pump House

34 13/06/2004 n/a - common for both units

28 DM Water by Customer

35 13/07/2004 n/a - common for both units

29 Foundation for TDBFP 35 13/07/2004 9/8/2004 2.0 Casted in July 2004.

30 Readiness of ESP Control Room with cat walk

35 13/07/2004 March 2005 8.0

31 Fdn. For PA fans with Lub oil pump fdn.

35 13/07/2004 12/08/2004 1.0 Fdns handing over started from 13/05/2004 (PA fan 4A).lub oil fdns are given on 12/08/2004

32 Chimney for Duct Connection

36 13/08/2004 21/06/2004 -

33 Fuel: Oil by Customer

40 13/12/2004 n/a - common for both units

34 Ash Handling system for BLU

41 13/01/2005 December 2006

- Make shift arrangement made at the time of BLU

35 Coal handling system by Customer

45 13/05/2005 ? Matched with the coal firing of unit#4

36 Power evacuation by Customer

45 13/05/2005 available -

37 Ash Dyke by Customer

45 13/05/2005 available -

38 Mill reject system 28/08/2004 July 2005 10.0 All the foundations are made in wrong direction. Bunker Fdn, Air receiver Fdn given in December 2005. Water seepage problem solved much later by pressure grouting.

Page 99 of 175

PG TEST CONDITIONS

The PG test at Rihand STPP is divided into 3 categories: CATEGORY – I : Under this category the equipments/ systems are to be demonstrated the performance guarantee requirements. Even any modification/ replacement is required to prove the guarantee, it is to be carried out within 3 months of test or a reasonable period allowed by NTPC. In case of failure, equipment/ system/ plant will either be rejected or levy of liquidated damage for shortfall of performance. CATEGORY – II: Under this category, the conformance to the performance requirement is mandatory. In case of failure, equipments will be rejected. CATEGORY – III: Under this category, guarantees do not attract the liquidated damage, the equipments/ system will either be rejected or will be accepted after assessing the deficiency in respect of the various ratings, performance parameters and capabilities by reducing the contract price equivalent to damages. The details are as bellows: Guarantees under category -I :

Sl. No. Guaranteed Parameters Guaranteed Figures

i

Turbine Cycle Heat rate in kcal/kwhr. Under rated steam conditions at 77mm Hg (abs) design condenser pressure with zero make up at 500 MW unit load.

1944.6 Kcal/kwhr

ii

Turbine Cycle Heat rate in KCAL/kwhr under rated steam conditions at 77mm HG (abs) design condenser pressure with zero make up at 400 MW Unit load

1989.3 Kcal/kwhr

iii

Turbine Cycle Heat rate in kcal/kwhr. Under rated steam conditions at 77mm HG (abs) design condenser pressure with zero make up at 300 MW unit load.

2065.2 Kcal/kwhr

iv

Turbine Cycle Heat rate in kcal/kwhr. Under rated steam conditions at 77mm Hg (abs) design condenser pressure with zero make up at 250 MW unit load.

2138.4 Kcal/kwhr

vi

Continuous TG output of 500MW under rated steam conditions at 89mm HG (abs) worst condenser pressure with 3% make-up.

500 MW

Page 100 of 175

vii

CW pumping power in KW for design CW flow through the condenser within BHEL’s terminal point corresponding to BHEL’s guaranteed pressure drop between these terminal points. (Power consumption shall be computed based on overall efficiency of 83% of CW pump and drive set.)

1982 kw per 500 MW Unit

viii

*Steam Generator efficiency in percentage, while firing design coal, at rated steam parameters, rated coal fineness and rated excess air at the following stipulated loads :

a) at 100% TMCR (500 MW Unit load) b) at 80% TMCR (400 MW Unit load) c) at 60% TMCR (300 MW Unit load) d) at 50% TMCR (250 MW Unit load)

*Air heater leakage used for efficiency calculations as percentage of BMCR flue gas flow to Air heaters (both Primary & Secondary) a) 100% TMCR load b) 80% TMCR load c) 60% TMCR load d) 50% TMCR load

87.12% 87.08% 86.94% 86.85% 8.26% 7.82% 7.43% 7.18%

ix

Minimum life of coal mill wear parts in hours of operation

a) Classifier vanes (hours of operation)

b) Classifier cone (hours of operation) c) Mill discharge valve (hours of operation)

d) Seal (hours of operation) e) Ceramic material wherever provided

(hours of operation) f) All other parts coming in contact with

coal (hours of operation) g) Grinding rolls (hours of operation)

h) Grinding Segments (hours of operation)

25,000 hrs. 25,000 hrs. 15,000 hrs. Not Applicable 25,000 hrs. 15,000 hrs. 6,000 hrs. 6,000 hrs.

x

Steam Generator capacity (each unit) in kg/hr. of steam at rated steam parameters at super heater outlet with any combination of mills working with the coal being fired from within the range specified.

1,675,000 kg/hr.

xi

Minimum sustained dust collection efficiency of ESP under guarantee point conditions, when firing design coal (without FGC in service).

To limit the outlet dust burden from ESP to 27 mg/MM3 (maximum)

xii

Auxiliary Power Consumption (Pa) The auxiliary power consumption for all the turbine generator auxiliaries, steam generator auxiliaries, Electrostatic Precipitator (without

17,342 kW per 500 MW unit including proportionate part of station auxiliaries.

Page 101 of 175

FGC System in service) but considering all ESP fields in service and other common auxiliaries required for continuous unit operation at 500MW load under rated steam conditions at condenser pressure of 89mm Hg (abs) with 3% make-up ambient air temperature and RH of 27o C and 60% respectively. The break up of the auxiliary power consumption is given below:

Auxiliaries

1. Power consumed by unit Aux.(PU) 2. Power consumed by STN. Aux.(PC) 3. Losses of Transformers supplies by

BHEL (TL)

Power Consumption (kw)

14,254 2,876 3,300

Guarantee under category – II :

xiii

Total NOx (from thermal as well as fuel) emission from each unit in grams per giga joule of heat input to the boiler for the entire operating range of steam generator

260 grams/giga joule

Guarantees under Category – III 1.00.0 TURBINE GENERATOR 1.01.0

TURBINE GENERATOR SET CAPABILITY: The steam turbine generator unit shall be capable of delivering at generator terminals the output following conditions:

a) Continuous output at generator terminals corresponding to VWO condition at under rated steam conditions at a condenser pressure of 77mm of Hg (Abs), 3% make- up to the cycle.

b) Maximum continuous output at generator

terminals corresponding to one string of HP heater out of operation, under rated steam conditions at a condenser pressure of 77mm of Hg (Abs) and 3% make up.

c) Maximum continuous output at generator terminals corresponding to one string of HP heater out of operation, under rated steam conditions at a condenser pressure of 77mm of Hg (ABS) and 0% make up.

524.944 MW 537.011 MW 545.0 MW

Page 102 of 175

1.02.0

d) Maximum continuous output at generator terminals corresponding to both strings of HP heaters out of operation, under rated steam conditions, at a condenser pressure of 77mm of Hg (Abs) and 3% make up.

e) Maximum continuous output at generator

terminals corresponding to both strings of HP heaters out of operation, under rated Steam conditions at a condenser pressure of 77mm of Hg (Abs) and 0% make up.

TURBINE AUXILIARIES: i) H.P./L.P. Bypass Capabilities: The HP & LP Bypass system should satisfy the following functional requirements under automatic interlock action. It should come into operation automatically under the following conditions. a) Generator circuit breaker opening b) HP-IP stop valves closing due to turbine tripping. c) Sudden reduction in demand to house load.

Under all these conditions, while passing the required steam flows as per the relevant heat balances, the condenser should be able to swallow the entire steam without increasing the exhaust hood temperature and condenser pressure beyond the maximum permissible value indicated by BHEL in its offer and accepted by the NTPC. The same shall be demonstrated. ii) Lube Oil Purification System – Capacity & Purity : The purity of purified oil at centrifuge outlet Shall be demonstrated under the design flow capacity of the purifier. iii) Steam Condensing Plant : a) Temperature of condensate, at outlet of condenser, shall not be less than saturation temperature corresponding to the condenser pressure at all loads. (b) Oxygen content in condensate, at hot well outlet, shall not exceed 0.015 cc per litre over the entire load range and shall be determined according to calorimetric Indigo-Carmine method. (c) Air leakage in the condenser under full load condition shall not exceed more than 50% of design value taken for sizing the condenser air evacuation system.

526.614 MW 534.918 MW Not applicable yes yes Yes Yes Yes Yes

Page 103 of 175

(d) When one half of the condenser is isolated, condenser shall be capable of taking at least 60% T.G. load under MCR conditions.

(e) The capacity of each vacuum pump in free dry air under standard conditions at a condenser pressure of 25.4 mm Hg (abs) and sub cooled to 4.17 deg. C below the temperature corresponding to absolute suction pressure shall not be less than 30 SCFM. Correction curves for establishing the capacity at site conditions shall also be furnished. (f) The air and vapour mixture from air cooling zone of condenser shall be 4.17 deg. C below the saturation temperature corresponding to 25.4 mm Hg (abs) suction pressure. Correction curves for establishing the capacity at site conditions shall also be furnished.

(g) Life of sponge rubber balls and number of balls lost during 1000 hours of plant operation shall be as indicated by BHEL in the offer and accepted by the NTPC. iv) Feed Water Heaters & Deaerator :

(a) TTD’s and DCA’s of feed water heaters in line with 500 MW heat rated guarantee heat balance shall be demonstrated.

(b) Dissolved O2 content in deaerator effluent at deaerator outlet without chemical dosing at all loads, not to exceed 0.005 CC/litre determined as per ASTM-D-888 reference method indigo carmine method.

(c) Difference between saturation temperature of steam entering the deaerator and temperature of feed water leaving deaerator. (d) Continuous & efficient operation and performance of feed heating plant without un due noise at all loads & duty conditions. v) Condensate Extraction Pumps :

(a) Each CEP set shall be capable of delivering the flow and total dynamic head corresponding to best efficiency point.

(b) Each CEP set shall be capable of delivering the flow and total dynamic head corresponding to run out point as specified.

Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes

Page 104 of 175

1.03.00

(c) The vibration, noise level and parallel operation of any two of the three pumps shall be demonstrated.

vi) Boiler feed Pumps :

(a) Each boiler feed pump set shall be capable to deliver flow and total dynamic head corresponding to best efficiency point as specified elsewhere.

(b) Each boiler feed pump set shall be capable to deliver flow and total dynamic head corresponding to run out point as specified elsewhere.

(c) The vibration, noise level and parallel operation of any two of the three pumps shall be demonstrated as per specification requirements.

vii) Turbine Hall EOT Crane :

Over load test, travel & hoist speed checks etc. shall be demonstrated as per IS:3177 (latest edition) Start-up, Loading, Unloading and Shutdown Capabilities (For Turbine Generator & Steam Generator) i) Start-up time (up to full load), and loading capabilities for the complete unit (steam generator & turbine Generator together) for cold start conditions (greater than 36 hours shutdown), warm start conditions (between 8 and 36 hours shutdown) and hot start conditions (less than 8 hours shutdown) shall be demonstrated, ensuring that the various turbine operational parameters like vibration, absolute and differential expansion, eccentricity and steam-metal temperature mismatch etc. and various steam generator operational parameters like tube metal temperature, excess air level etc. are within design limits. ii) Sudden Total Loss of External Load :

On occasions, the steam turbine generator unit may experience sudden total loss of all external load. Under these conditions, the steam turbine generator unit shall not trip on over speed but shall continue to be in operation under the control of its speed governor to supply power for the plant auxiliary load with HP-LP bypass in operation while staying within the agreed limits of steam metal temperature mismatch, exhaust hood temperature, absolute and differential expansion, vibration and eccentricity. The same shall be demonstrated.

Yes Yes Yes Yes Yes As per start up curves Yes

Page 105 of 175

1.04.00 1.05.00

Noise :

All the plant, equipment and systems covered under this specification shall perform continuously without exceeding the noise level over the entire range of output and operating frequency specified. Noise level measurement shall be carried out using applicable and internationally acceptable standards. The measurement shall be carried out with a calibrated integrating sound level meter meeting the requirement of IEC 651 or IS:5969 or IS:9779. Sound pressure shall be measured all around the equipment at a distance of 1.0m horizontally from the nearest surface of the machine and at a height of 1.5m from the floor level in elevation. A minimum of 6 points around each equipment shall be covered for measurement. Additional measurement points shall be considered based on the applicable standards and the size of the equipment. The measurement shall be done with slow response on the A-weighting scale. The average of A - weighted sound pressure level measurements expressed in decibels to a reference of 0.0002 micro bar shall not exceed the guaranteed value. Corrections for background noise shall be considered in line with the applicable standards. All the necessary data for determining these corrections, in line with the applicable standards, shall be collected during the tests. Steam Generator and Auxiliaries :

i) Coal Pulverisers capacity with design coal at rated fineness and with mill loading not exceeding 90% of maximum rated capacity (Tonnes/hr) ii) Minimum steam generator (% BMCR) load above which no oil support is required. iii) Performance characteristics of Fan (capacity, head developed etc.) iv) Capabilities of all drives. v) Margin on fans vi) Run back capabilities

In line with specification, however noise level under HP/ LP Bypass operation will be limited to 120 DBA. 90% of 60.0 T/HR 30% BMCR with adjacent coal elevations in service and mill load not less than 50%. As per fan curves. Technical data sheets. Yes As per table

Page 106 of 175

vii) Demonstration of boiler operation, rate of change of load and sudden load change withstand capability with important parameter deviations within permissible limits. viii) Maximum Furnace exit gas temperature (degree Celsius) (MHVT value) ix) Cold air velocity test (CAVT): (a) Maximum average flue gas velocity at different steam generator sections (m/Sec.) (b) Maximum deviation at each section with respect to average flue gas velocity (%) x) Flue Gas temperature at entry & exit of various boiler heating surfaces (Actual/MHVT values).

xi) Maximum steam temperature imbalance at super heater (SH) & re heater (RH) outlets between left and right header (degree Celsius). xii) (A) Maximum SH/RH at temperature spray water flow (T/hr) at all loads up to and including BMCR and with any coal from within the range specified. (a) Super Heater Attemperation (b) Re heater Attemperation (B) Maximum super heater Attemperation spray water flow in T/hr. while firing design coal and maintaining rated SH outlet steam temperature, etc. at : (i) 100% TMCR (500 MW unit load) (ii) 80% TMCR (400 MW unit load) (iii) 60% TMCR (300 MW unit load) (iv) 50% TMCR (250 MW unit load) (xiii) Gas tightness efficiency for dampers (% on flow) (xiv) Air heater air in leakage (% of gas flow at AH inlet)

As per table Yes (By back working) 10.0 ± 20% Technical data sheets (by back working) Yes 2.0 48.5 74.4 71.4 99.95% (Guillotine and Diverter Damper) Combined primary & Secondary air heater leakage is not more than 8.26% of BMCR flue gas flow entering the air heater at TMCR DC.

Page 107 of 175

(xv) Steam generating capacity of boiler heat when one and or both strings of HP heaters are out of operation. (T/hr) (xvi) Demonstration of SG C&I integration with DDCMIS and (TG C&I with important parameters within permissible load. (xvii) Minimum load (% BMCR) with separator is running dry. (xviii) Steam purity at drum outlet (%) applicable for drum type boiler.

(xix) Maximum air in leakage in ESP percentage at the guarantee point conditions. (xx) Maximum pressure drop (in mmwc) through ESP at the guarantee point flow condition.

(xxi) Demonstration of gas distribution among various among gas streams and fields of ESP within limits specified in IGCI publication for EP7. (xxii) Fuel oil preparation & firing system load carrying capacity. (xxiii) Start up time of steam generator (minutes) for constant pressure operation mode as well as variable pressure operation mode for cold, warm and hot start-up. (xxiv) Maximum noise level (dBA) as per specification requirements. (xxv) The demonstration parameters/ capabilities of other equipments shall be as per specification requirement.

) (xxvi) Minimum sustained dust collection efficiency of ESP (with FGC in service), under guarantee point conditions, at BMCR load worst coal firing.

(xxvii) Aux. Power consumption in KW, considering ESPs and FGC System in operation.

Limited to BMCR Heat input. Yes Not applicable Technical description of SG 1% of ESP inlet gas flow 15mmwc Yes 30% BMCR Start up curves Yes Yes To limit the outlet dust burden from ESP to 50 mg/NM3 (Maximum) 17592 KW

Page 108 of 175

(xxviii) other major operating capabilities of plant & equipments as per specification requirements like air conditioning & ventilation, Fuel oil handling plant, auxiliary water system pumps, power cycle piping, EOT cranes, Passenger lifts, Electrical system & switch yard, HOT cranes/ mono rails, Fire protection system, Equipment cooling water system, Condensate polishing unit, compressed air system, mill reject system, Effluent treatment system, control & instrumentation system requirements etc.

Yes

VWO – valve wide open Abs – absolute SCFM – Standard cubic feet per minute TTD – Terminal temperature difference DCA – Drain cooling approach BMCR – Boiler maximum continuous rating MHVT – Multi – shielded high velocity thermocouple (used for maximum furnace exit temperature FEGT) CAVT – Clean air velocity test TMCR – Turbine maximum continuous rating DDCMIS – Distributed digital control – Management information system FGC – Flue gas conditioning skid

Page 109 of 175

TOOLS AND PLANTS MAJOR T&Ps DEPLOYED BY BHEL:

325MT CRANE FMC-LS718 WITH HLA - 1NO

150MT CRANE FMC LS248 – 1 NO

150MT CRANE KH700 – 1NO

100MT CRANE KH500 – 1 NO

75MT CRANES – 5 NOS

25MT CRANE – 1 NO

12MT HYDRA CRANES – 2NOS

WITH REGULAR PREVENTIVE MAINTENANCE BREAK DOWN TIME OF CRANES REDUCED TO LESS THAN 1% DURING THE PERIOD OF DEPLOYMENT OF CRANES.

Page 110 of 175

OFFICE, STORAGE & HOUSING

OFFICE: • AREA OF APPROX. 600 SQ METER. ARRANGED FROM NTPC AND RENOVATED. •24 NOS P-IV PCs, 3 NOS PRINTERS AND 1 NO PLOTTER CONNECTED IN LAN WITH SERVER. •GLASS PANED PARTITION IN HALL FOR EDP ROOM. STORE YARD AND SHEDS: •OPEN STORAGE YARD -LEVELLED & FENCED 85000 SQ METER. ROAD WBM PAVED FOR CRANE MOVEMENT FOR MATERIAL RETRIEVAL IN ALL SEASONS. •COVERED STORAGE SHEDS - 5 NOS FULLY COVERED SHEDS OF SIZE 900 SQ METER EACH. OUT OF WHICH 4 NOS ARE DISMANTABLE TYPE AND HAVING HAND OPERATED OVERHEAD TOWER CRANES. - 2 NOS SEMI COVERED SHEDS OF SIZE 800 SQ MT EACH MADE FROM OTHER SITES DIVERTED MATERIALS. HOUSING: •NO OUTSIDE ACCOMMODATION AVAILABLE AT RIHAND AND BHEL HAS TO MAKE ITS OWN ARRANGEMENT FOR HOUSING AS PER CONTRACT. •BHEL CONSTRUCTED 35 NOS QUARTERS AT RIHAND. •BALANCE HOUSES MANAGED WITH NTPC. THEY PROVIDED 24 NOS QUARTERS AND HOSTEL ROOMS WHICH NEEDED COMPLETE RENOVATION. BHEL MADE THESE HOUSES READY FOR OCCUPATION AND SAVED MORE THAN ONE CRORE.

Page 111 of 175

AGENCIES DEPLOYED FOR 2X500MW SL NO

AREA AGENCY

BHEL PS WR 1 SITE INFRASTRUCTURE (CIVIL) BRIGHT CONST. 2 STORE SHEDS NEW LIFE STEEL STRUCTURE 3 RENOVATION OF HOUSES (TYPE-

I) KAVERI ENGG

4 CONST. OF HOUSES AVM CONSTRUCTION 5 RENOVATION OF HOUSES (TYPE-

II, III, NEELGIRI) SC GUPTA, JHANSI

6 LIGHTING MAST BAJAJ ELECTRICALS 7 BOILER ERECTION#3 TATA PROJECTS 8 BOILER ERECTION#4 PCP INTERNATIONAL 9 ESP ERECTION # 3 KARPARA 10 ESP ERECTION # 4 SUNIL HITECH 11 POWER CYCLE PIPING#3 PETRON 12 POWER CYCLE PIPING#4 PETRON 13 LP PIPING#3&4 KARPARA 14 CW PIPING#3&4 GAYTECH 15 TG ERECTION#3 EEPL 16 TG ERECTION#4 POWER MECH 17 INSULATION#3&4 BHAVANI ERECTORS 18 CONSTRUCTION POWER DAMODHAR TECH INTERNATIONAL 19 MAIN ELECTRICAL

PACKAGE#3&4 MAHATI ELECTRICALS

20 CABLING, EARTHING TECHNO ELECTRIC 21 STATION LIGHTING BAJAJ ELECTRICALS 22 C&I (WR SCOPE) PACE CONTROL 23 PAINTING ARUN CONSTRUCTION 24 EOT FAFECO 25 COMPRESSED AIR SYSTEM ATLAS COPCO 26 ELEVATOR in service building. KONE 27 MISC STRUCTURE SUNIL HITECH 28 MISC TANKS SHAKTI HITECH 29 CPU DRIPLEX 30 ETP DRIPLEX 31 AIR CONDITIONING ABB LTD 32 VENTILATION ABB LTD 33 MILL REJECT SYSTEM MACABBER BEKAY 34 FIRE PROTECTION SYSTEM WORMALD 35 FUEL OIL HANDLING SYSTEM TECHNO FAB

Cont….

Page 112 of 175

SL NO

AREA AGENCY

36 FLUE GAS CONDITIONING SYSTEM

BACHMANN INDIA LTD

37 FIRE SEALING OF CABLE ENTRY IN THE CABLE VAULT.

LLYODS INSULATION

38 PA System BYTES COMMUNICATION 39 MATERIAL HANDLING K SESHAGIRI RAO 40 CRANE MAINTENANCE VIJAY ENTERPRISIS 41 HIRING OF KH700 SANGHVI MOVERS 42 RUBBER LINING FOR ACID

CLEANING (PSWR) CORI INDUSTRIES

OTHER BHEL AGENCIES

43 NMEJs (TRICHY) KE BURGMANN 44 ELEVATORS FOR BOILER # 3&4

(TRICHY) KONE ELEVATORS

45 TURBINE INSULATION (HARDWAR)

MINWOOL

46 EXCITOR ANTI NOISE COVER FAB, TURBINE CLADDING & INSULATION (Hardwar)

INDIRA INDUSTRIES, RANIPET

47 INSULATION & SOUND PROOFING IN DG ROOM (ISG)

LLYODS INSULATION

48 TD BFP (all 4 nos) INSULATION, ANTI- NOISE COVER & CLADDING (Hyderabad)

LLYODS INSULATION

49 400 KV SWITCH YARD (TBG BHOPAL)

DEV DENSRO

50 STATION C&I (EDN SCOPE) IL KOTA NTPC DIRECT AGENCIES

51 TRACK HOPPER, COAL HANDLING PLANT (ISG BANGALORE)

GDC + ELECON + ECMM + GAYTECH + ARUN

52 MAIN PLANT CIVIL WORKS + P/W & BUNKER STRUCTURE

NBCC (SHANKAR BROS.) + RS AVTAR SINGH

53 CHIMNEY NBCC + SUNIL HI TECH 54 OFF SITE CIVIL WORKS EPIL 55 DM PLANT ION EXCHANGE + BRIDGE & ROOF 56 PRE TREATMENT PLANT BRIDGE & ROOF 57 COOLING TOWER PAHARPUR 58 ASH HANDLING SYSTEM BURN STANDARD 59 ASH DYKE HSCL 60 CW PUMP HOUSE KBL + L&T 61 ASH WATER RECIRCULATION

SYSTEM ISG, BHEL BANGALORE

Page 113 of 175

MILESTONE DATES RIHAND STPP UNIT-3

AS PER L1 SCHEDULE Contractual SL NO

MILESTONE

MILESTONE DATE

MONTHS

ACTUAL

DATE DELAYS (DAYS)

DELAYS (MONTHS)

1 ZERO DATE 14.08.2001 0 14.08.2001 14.12.2001 0 0

2 BOILER ESP INSULATION ERECTION START

13.07.2002 11 24.09.2002 19.10.2002 05.04.2004

13.11.2002 -48 -1.6

3 DRUM LIFTING 13.01.2003 17 29.03.2003 13.05.2003 -45 -1.5

4 CONDENSER ERECTION START

13.05.2003 21 14.05.2003 13.09.2003 -122 -4.1

5 TG ERECTION START 13.07.2003 23 11.07.2003 13.11.2003 -125 -4.2

6 -POWER CYCLE PIPING START -CW PIPING START

15.12.2003

24.04.2003

7 HYDRAULIC TEST 13.01.2004 29 30.01.2004 13.05.2004 -103 -3.4

8 TG BOX UP 13.04.2004 32 26.06.2004 13.08.2004 -48 -1.6

9 BOILER LIGHT UP 13.07.2004 35 28.09.2004 13.11.2004 -46 -1.5

10 ABO 13.07.2004 35 11.10.2004 13.11.2004 -33 -1.1

11 ACID CLEANING 13.08.2004 36 30.10.2004 03.11.2004

13.12.2004 -40 -1.3

12 TG OIL FLUSHING COMPLETION

13.07.2004 35 01.09.2004 24.10.2004

13.11.2004 -20 -0.7

13 BARRING GEAR 13.07.2004 35 29.12.2004 13.11.2004 46 1.5

14 STEAM BLOWING COMPLETION

13.09.2004 37 27.11.2004 22.12.2004

13.01.2005 -22 -0.7

15 SYNCHRONIZATION WITH OIL

13.11.2004 39 26.01.2005 31.01.2005

13.03.2005 -46 -1.5

16 SAFETY VALVE FLOATING

13.10.2004 38 26.04.2005 13.02.2005 72 2.4

17 COAL FIRING/ SYNCHRONIZATION

13.11.2004 39 Coal firing - 28.04.2005

Synch - 29.04.2005 Full Load 500MW

19/06/2005 0945AM

13.03.2005 47 1.6

18 Full load 500MW 13.01.2005 41 19.06.2005 13.05.2005 37 1.2

19 COMMERCIAL OPERATION

13.02.2005 42 15.08.2005 13.06.2005 63 2.1

20 TRIAL RUN AND ALL FACILITY COMPLETION

13.02.2005 42 09.10.2005 (started at

0.00hrs 10.09.2005 for

30 days)

13.06.2005 118 3.9

THE CONTRACTUAL DATE IS 4 MONTHS PLUS L1 DATE

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MILESTONE DATES RIHAND STPP UNIT-4

AS PER L1 SCHEDULE Contractual SL NO

MILESTONE

MILESTONE DATE

MONTHS

ACTUAL

DATE DELAYS (DAYS)

DELAYS (MONTHS)

1 ZERO DATE 14.02.2002 6 14.02.2002 14.05.2002 0 0

2 BOILER ESP INSULATION ERECTION START

13.01.2003 17 06.02.2003 05.03.2003 08.11.2004

13.04.2003 -66 -2.2

3 DRUM LIFTING 13.07.2003 23 11.07.2003 13.10.2003 -94 -3.1

4 CONDENSER ERECTION START

13.11.2003 27 29.11.2003 13.02.2004 -76 -2.5

5 TG ERECTION START 13.01.2004 30 31.01.2004 13.04.2004 -72 -2.4

6 HYDRAULIC TEST 13.07.2004 35 19.06.2004 13.10.2004 -119 -4.0

7 TG BOX UP 13.10.2004 38 19.03.2005 13.01.2005 65 2.2

8 BOILER LIGHT UP 13.01.2005 41 10.05.2005 13.04.2005 27 0.9

9 ABO 13.01.2005 41 22.05.2005 13.04.2005 39 1.3

10 ACID CLEANING 13.02.2005 42 08.06.2005 13.06.2005

13.05.2005 31 1.0

11 TG OIL FLUSHING COMPLETION

13.01.2005 41 15/5/2005 29/6/2005

13.04.2005 77 2.6

12 BARRING GEAR 13.01.2005 41 8/31/2005 13.04.2005 140 4.7

13 STEAM BLOWING COMPLETION

13.03.2005 43 7/7/2005 26/7/2005

13.06.2005 43 1.4

14 SYNCHRONIZATION WITH OIL

13.05.2005 45 9/24/2005 13.08.2005 42 1.4

15 SAFETY VALVE FLOATING

13.04.2005 44 18/09/2005 19/09/2005

03/02/2006

13.07.2005 205 6.8

16 SYNCHRONIZATION & COAL FIRING

13.05.2005 45 Coal firing - 04/12/2005

Synch. - 05/12/2005 (0200hrs)

Full load 500MW on 15/02/2006

08:04PM

13.08.2005 114 3.8

17 Full load 500MW 13.07.2005 47 15.02.2006 13.10.2005 125 4.2

18 COMMERCIAL OPERATION

13.08.2005 48 01.04.2006 13.11.2005 138 4.6

19 TRIAL RUN AND ALL FACILITY COMPLETION

13.08.2005 48 14.03.2006 to 12.04.2006

13.11.2005 150 5.0

THE CONTRACTUAL DATE IS 3 MONTHS PLUS L1 DATE

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78 89 48 39 TOTAL P&C WOOL TOTAL STR PP NPP ROT TP TOTALSep-02 1 168 168 168Oct-02 2 30 30 347 347 377Nov-02 3 171 171 1004 1004 1175Dec-02 4 351 351 658 658 1009Jan-03 5 451 451 657 657 1108Feb-03 6 468 468 589 589 1057Mar-03 7 399 399 458 244 702 1101Apr-03 8 436 436 181 181 617May-03 9 506 506 293 475 768 1274Jun-03 10 416 12 27 455 286 662 83 1031 1486Jul-03 11 460 8 164 632 190 520 109 819 1451Aug-03 12 299 7 44 350 205 430 57 692 1042Sep-03 13 209 13 6 228 171 388 1 14 574 802Oct-03 14 165 21 16 202 105 318 154 164 741 943Nov-03 15 244 122 366 195 636 159 1081 2071 2437Dec-03 16 315 173 34 522 273 301 307 109 990 1512Jan-04 17 236 194 81 511 152 89 117 647 22 1027 1538Feb-04 18 119 18 153 25 315 122 2 441 189 20 774 1089Mar-04 19 70 6 71 146 293 265 532 389 21 1207 1500Apr-04 20 25 3 66 146 240 12 12 148 15 207 173 9 552 804May-04 21 48 5 79 119 251 77 25 102 173 21 318 229 5 746 1099Jun-04 22 75 84 70 229 66 65 131 262 45 140 92 9 548 908Jul-04 23 62 90 34 186 49 125 174 205 7 195 30 9 446 806Aug-04 24 92 2 201 64 359 118 136 254 247 1 205 4 28 485 1098Sep-04 25 110 76 21 207 120 172 292 201 8 204 77 8 498 997Oct-04 26 155 20 68 98 341 20 210 230 127 67 114 33 5 346 917Nov-04 27 205 134 121 460 184 184 187 126 118 29 460 1104Dec-04 28 158 4 15 32 209 107 107 175 12 296 217 21 721 1037Jan-05 29 152 9 47 84 292 140 140 95 10 289 80 5 479 911Feb-05 30 128 22 14 71 235 68 68 167 11 302 100 13 593 896Mar-05 31 29 5 50 84 165 165 206 6 235 96 4 547 796Apr-05 32 125 125 117 3 257 74 7 458 583May-05 33 142 142 113 324 43 18 498 640Jun-05 34 136 136 40 98 38 2 178 314Jul-05 35 100 100 80 66 1 147 247Aug-05 36 59 59 166 23 1 190 249Sep-05 37 31 31 117 17 13 147 178Oct-05 38 18 18 69 15 3 87 105Nov-05 39 1 8 9 35 35 44Dec-05 40 46 46 46Jan-06 41 66 66 66Feb-06 42 94 94 94Mar-06 43 21 21 21

6584 150 1592 1453 9779 451 2028 2479 9476 4271 5391 4015 235 23388 35646

PG-78 MAIN ESP P&C -POURABLE & CASTABLE STR -STRUCTUREPG-89 PLATEFORMS WOOL -INSULATION WOOL & PP -PRESSURE PARTSPG-48 DUCTING AL CLADINGS NPP -NON PRESSURE PARTSPG-39 SUPPORT STRUCTURE ROT -ROTARY EQUIPMENTS

TP -TRIM PIPING

Grand Total

BOILER UNIT # 3 - MONTH WISE TONNAGE ACHIEVEDESP INSULATION BOILER GRAND

TOTALMONTH

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78 89 48 39 TOTAL P&C WOOL TOTAL STR PP NPP ROT TP TOTALFeb-03 1 409 409 409Mar-03 2 225 225 1068 1068 1293Apr-03 3 257 257 633 633 890May-03 4 378 378 602 602 980Jun-03 5 331 331 729 77 806 1137Jul-03 6 311 311 638 272 910 1221Aug-03 7 93 4 97 133 281 414 511Sep-03 8 115 4 119 171 159 189 519 638Oct-03 9 219 1 220 202 254 100 556 776Nov-03 10 441 8 449 235 590 3 828 1277Dec-03 11 874 874 152 874 1026 1900Jan-04 12 672 3 675 119 735 107 961 1636Feb-04 13 501 17 518 123 413 137 283 956 1474Mar-04 14 321 11 332 162 151 63 878 1254 1586Apr-04 15 212 17 229 148 125 157 585 1015 1244May-04 16 112 8 54 174 196 98 195 219 708 882Jun-04 17 154 20 174 154 31 139 48 19 391 565Jul-04 18 57 101 33 191 133 12 242 218 9 614 805Aug-04 19 105 17 122 169 8 209 301 9 696 818Sep-04 20 58 29 92 179 152 3 267 49 18 489 668Oct-04 21 77 147 45 269 105 3 265 130 10 513 782Nov-04 22 111 166 97 374 17 7 24 105 10 240 121 14 490 888Dec-04 23 164 139 123 426 60 54 114 106 8 265 64 5 448 988Jan-05 24 108 261 122 491 107 93 200 59 5 161 42 8 275 966Feb-05 25 74 22 220 73 389 93 71 164 163 12 124 91 8 398 951Mar-05 26 178 5 124 240 547 144 110 254 109 36 193 89 427 1228Apr-05 27 133 22 76 147 378 28 193 221 105 1 99 61 1 267 866May-05 28 54 10 22 1 87 218 218 137 30 68 51 10 296 601Jun-05 29 65 1 81 75 222 203 203 143 31 110 99 1 384 809Jul-05 30 45 103 19 167 186 186 110 19 179 157 24 489 842Aug-05 31 29 15 82 106 232 211 211 89 13 244 49 10 405 848Sep-05 32 66 2 9 77 243 243 68 9 240 14 10 341 661Oct-05 33 2 26 15 43 156 156 146 19 167 155 6 493 692Nov-05 34 3 4 4 11 129 129 61 176 48 2 287 427Dec-05 35 1 29 30 1 85 86 38 311 37 4 390 506Jan-06 36 5 1 9 15 53 53 47 208 179 8 442 510Feb-06 37 3 33 36 16 16 27 97 2 28 154 206Mar-06 38 30 48 78 11 11 136 224 18 2 380 469Apr-06 39 21 21 105 49 7 30 191 212May-06 40 15 15 64 35 13 1 113 128Jun-06 41 10 10 86 14 1 101 111Jul-06 42 2 2 98 14 112 114Aug-06 43 0 130 3 133 133Sep-06 44 0 136 3 139 139Oct-06 45 157 2 159 159Nov-06 46 250 26 276 276Dec-06 47 198 18 216 216Jan-07 48 170 170 170

6583 150 1592 1450 9775 450 2039 2489 9476 4279 5340 4012 237 23344 35608

PG-78 MAIN ESP P&C -POURABLE & CASTABLE STR -STRUCTUREPG-89 PLATEFORMS WOOL-INSULATION WOOL & PP -PRESSURE PARTSPG-48 DUCTING AL CLADINGS NPP -NON PRESSURE PARTSPG-39 SUPPORT STRUCTURE ROT -ROTARY EQUIPMENTS

TP -TRIM PIPING

MONTH

BOILER UNIT # 4 - MONTH WISE TONNAGE ACHIEVEDGRAND TOTAL

Grand Total

ESP INSULATION BOILER

Dec-06, Jan-07 figures are likely.

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ERECTION STRATEGY FOR BOILER – NTPC RIHAND STPP STAGE - 2

BASIC STRATEGY: Basic strategy shall be to go in for cycle time reduction in every area by taking up erection of all possible fronts Parallelly , system completion at first go itself and by applying innovative ideas and modern erection practices. To achieve this we shall have highly experienced and effective execution team posted at site with back up of strong infrastructural support made available to them. They shall be always aiming for achieving the project milestones as planned by changing the intermediate course of direction depending on availability of inputs. The infrastructural support and basic erection sequences / strategy are explained below. SUBCONTRACTING STRATEGY: Subcontractors shall be finalized from the list of vendors duly approved by NTPC (as applicable as per agreement) for following packages, 1) Main boiler and Rotating equipments 2) ESP and Flue gas duct beyond boiler 3) Power Cycle piping 4) Lining and insulation INSPECTION & QUALITY: An exclusive ‘Quality group’ at site ensures all installation checks and stage protocols with respect to approved quality plans for individual system, involving Consultant/ Customer representatives. In addition to this, to ensure system completion, before execution of a defined Mile Stone activity during installation, an audit team from PS-WR HQ visits the site before Construction Manager is permitted to execute the Mile Stone activity.

SAFETY: An exclusive officer shall be deployed at job site to guide, monitor and control all HSE related activities as per company’s HSE instructions. He shall directly report to Construction Manager. Also our erection agencies shall nominate exclusive safety supervisor to assist us. MATERIAL MANAGEMENT: Unique identification system for components is utilized by all BHEL units. A strong team of officers and supervisors shall keep intensive track records of dispatches, receipt, storage and issues of components using modern electronic media.

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On receipt, components shall be inspected and verified before storage. Exclusive Material Receipt cum Inspection Reports shall be prepared along with Consultant/Customer representative. Components shall be stored in Open, Semi-closed, closed or special environment conditions as applicable. They shall be preserved during storage and installation stages as per the instruction given in our preservation manual. A comprehensive tracking system, with appropriate records shall be maintained for all issues. DOCUMENTATION AT SITE: A totally computerized documentation system shall be adopted at site to keep track of total drawings and manuals required to complete installation to ensure proper monitoring of receipt, issue and revisions. FACILITY ENGINEERING AT SITE: An exclusive executive shall be deployed to supervise and monitor the availability of T&P’s being provided by BHEL.

TOOLS AND PLANTS: Sufficient numbers of T&P s shall be deployed either by BHEL or by their erection agencies. MANPOWER DEPLOYMENT: Sufficient number of BHEL staff shall be posted for installation of this package. Following shall be tentative manpower (main category) deployment plan per unit by erection agencies; Boiler erection agency: Engineer- 7 , supervisors- 15 ,Rigger foreman- 2 , Fitters- 27 , Structural welder – 30 , HP welder – 12 , Gas cutter - 4 , Grinder – 10 , SR technician – 4 , Radiographic Technician- 4 ESP erection agency: Engineer- 1 , supervisors- 4 ,Rigger foreman- 1 , Fitters- 12 , Structural welder – 15 , Gas cutter- 2 , Grinder-2 Piping erection agency: Engineer- 3 , supervisors- 6 ,Rigger foreman- 2 , Fitters- 12 , Structural welder – 10 , HP welder – 10 , Gas cutter - 2 , Grinder- 6 , SR technician – 4 , Radiographic Technician- 4

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ERECTION SEQUENCE: BOILER SUPPORTING STRUCTURE: Main supporting structure columns (Nos. S1to S6 L&R, S7 to S12 L&R, S13L&R, shall be erected in following combinations:

Bottom tier - single piece 2nd & 3rd tier combined with Tata 75 MT and Link Belt LS 248H 4th & 5th tier combined 6th & 7th tier combined ---------------- with FMC LS 718 HLA 330 ft boom + Jib All connected horizontal beams, MBL members, and vertical diagonal bracings as required to maintain verticality of the columns shall be erected before proceeding to next level. All MBL members between box of four columns shall be judiciously pre assembled on ground to ensure better workmanship and speedy erection. Erection of all balance items of such components shall precede parallels and shall be completed prior to ceiling girder lifting. It may be noted that all columns for Rihand shall be trial assembled in full length at Trichy, hence pre assembly and joint matching at site shall not be required. Once the structure as mentioned above are erected and verticality of columns are ensured Ceiling girder erection shall start. Ceiling Girder Erection shall be done in following sequence: With 1st rigged position of FMC - Girder '0', Girder-A, Girder-'B' With 2nd rigged position of FMC -Girder-'C', Girder-'D' With 3rd rigged position of FMC - Girder-'E' Ceiling girders will be supplied in three pieces and shall be pre assembled on ground before lifting. It may be noted that casting of foundation pedestal of FD fan-B to be hold till ceiling girder C&D is shifted to boiler cavity after pre assembly. Also it may be noted that the bottom most vertical diagonal bracing between columns S10 R&S11R will not be erected for this purpose. Designer clearance towards this is already obtained. For erection of structure as mentioned above the basic sequence of erection will be from front to rear i.e. from Row-D to L keeping the crane inside boiler cavity. Entries of cranes are envisaged from right side of boiler through rear of boiler i.e. from between boiler rear and mill bay col. i.e between Row-L&M. For movement of crane inside boiler cavity it will be necessary to hold erection of middle /air pre heater columns namely Columns Nos. S15L&R , S16L&R, S17, S18, S19L&R, S20L&R, S21, S24R, S25R,

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S29R,FH-11R,FH-12R, Mill bay M & N row columns. Also it should be ensured that the foundation pedestals of columns S15L&R, S16L&R, S17, S18, S19L&R, S20L&R, S21, Mill bay M row cols 2nos at center do not project above ground. Columns nos. S15L&R, S16L&R and its connecting bracings will be erected as soon as FMC moves out to clear the area after Ceiling girder A&B is erected, but necessarily have to be erected before Ceiling girder –C erection. Columns nos. S17 , S18 and its connecting bracings will be erected as soon as FMC moves out to clear the area after Ceiling girder C & D is erected , but necessarily have to be erected before Ceiling girder –E erection. Columns Nos S14L&R and its connecting bracings shall be erected immediately after boiler drum is erected. Erection of balance columns Nos. S19L&R , S20L&R , S21, S22L&R , S24L&R , S25L&R , S26L&R , S27L&R , S28L&R , S29L&R and its connecting bracings shall be erected independently after ceiling girder erection is completed and FMC crane is moved out. BOILER DRUM UNLOADING AND ERECTION: In case of unit-3 the boiler drum will be received by rail near to boiler LHS i.e. co-ordinate approx 2075N, 2250E. Boiler drum will be unloaded with the help of two cranes namely LS248H 180MT and Manotowoc 250MT by the boiler erection agency. The drum then shall be dragged onto temporary rails to boiler cavity. In case of unit-4 the boiler drum will be unloaded at the same location and the drum shall be dragged on to temporary rails to unit-4. Boiler drum will be lifted in single stage with help of two nos 15MT electric winches and pulleys suspended from temporary structure (will be either fabricated at site or will be diverted from other site) at top. Winches will be placed in front of ESP and will be anchored with the help of concrete counterweights of FMC crane placed in pit. After the drum is aligned the lifting arrangement will be removed and pressure part erection will follow. PRESSURE PART ERECTION AND HYDRAULIC TEST: Being top suspended type of boiler, general sequence of erection of pressure part will be from top to bottom and from outside to in side . Actual sequence of erection will be decided at site depending on the sequence of material receipt at site. However our aim shall be to go for maximum possible pre assembly of pressure part components on ground or optimization at works , so that to reduce numbers of lifts and to achieve better quality which will effectively reduce erection cycle time.

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Following pre assemblies / optimization at works are envisaged:

a) All headers above roof will be assembled in single piece b) All possible assemblies to handle able sizes in lines and links above

roof c) All crown plates with end bars for coil suspension above roof d) Furnace radiant roof – Front - in seven assemblies (each block of

suspension arrangement), Inlet header shall be lifted separately in single piece and joining with tubes shall be done in position. Rear – in two assemblies (each block with piece of out let header )

e) Back pass furnace roof with all hanger tubes above it along with inlet header in single assy.

f) Back pass front wall hanger tubes with suspension end bars. g) Back pass front wall upper with lower panels h) Back pass side wall upper panels to inter panels i) Back pass rear wall upper panels to inter panels j) Back pass rear lower walls with two headers(complete assy) k) Extended water wall upper panel with lower(individual) l) Furnace rear wall upper panels with hanger tubes and arch tubes(

individual panel) m) Burner panels with lower inter panels ( individual panels) n) Furnace side Lower inter walls with lower walls ( individual panels) o) Furnace front and rear lower panels with floor panels( individual

panels) p) LTSH upper coils to lower coils. ( individual coils) q) Economizer upper with intermediate coils( individual coils) r) Sh. Divisional panels front assy to rear assy (individual panels) s) Furnace bottom Z panels with floor panels and loose tubes t) All buck stays with stirrups and key buck stays u) Super heater and Re heater spray control stations

However a judicious re look into above assemblies will be essential after detailed engineering of pressure part is completed. Material feeding for first pass will mostly be done from RHS of boiler between columns S8&9 on temporary rail. For back pass material shall be fed from rear side. Also modern erection practices like use of omega lugs, anti deformation frame for handling of Eco , Super heater and Re heater coils , special lifting tackle for coil lifting will be inducted for safe and quicker erection of pressure part. Hydraulic test of boiler will be done in three parts. Drainable part includes the circulation system and drainable portion of the super heater. During this the link connecting the non drainable portion of super heater shall be dummied. This will facilitate early clearance for insulation of water walls and back pass walls required for light up. Non drainable part, which includes the non drainable portion of the super heater system also, will be done just prior to boiler light up so that preservation and rusting of super

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heater system can be avoided. Re heater hydraulic test shall be done along with reheat system piping before steam blowing operation. AIR AND FLUE GAS DUCTING ERECTION: Air and flue gas ducting erection shall be taken up parallelly with boiler pressure part so as to reduce the gap between boiler hydro test and light up. Almost all duct (excepting duct like below back pass U-headers etc. ) shall be pre assembled on ground and shall be kerosene tested to reduce ,number of lifts and work in position which will in turn reduce erection cycle time. The assembled duct will mostly be fed with help of crane from sides of boilers. However the inter connecting hot secondary air duct will be assembled below boiler, for straight lift. AIR PRE HEATER ERECTION: Air pre heater erection shall be taken up immediately after the structure is getting ready after ceiling girders lifting. Most of components will be lifted with crane (Monitowoc-250MT and FMC –350 MT one on either side) depending on accessibility which will help in reducing erection cycle time. FANS ERECTION: This being independent parallel activity it will be taken up as early as possible depending on availability of foundations. There is fixed sequence of erection of fans as specified in erection manual, the same shall be followed strictly. MILLS ERECTION : Shall be taken up after availability of foundations. There is fixed sequence of erection of mills as specified in erection manual, the same shall be followed strictly. Major components like mill base, air compartment, separator body, mill top / classifier assy, MDV assy will be placed with crane KH500. NTPC to coordinate with mill bay structure erection agency regarding hold in structural bracings etc. for crane approach. ESP ERECTION: This is altogether an independent island. ESP erection shall be started as soon as column foundations and material is available. It has an almost fixed sequence of erection. In ESP also we shall go for all possible pre assembly like casing walls, hopper walls etc. Collecting electrode will be inserted from bottom. POWER CYCLE PIPING ERECTION: This will be treated as a highly specialized work, especially in case of P-91 (High Crome alloy steel). The erection can start from any side terminal point, however normal sequence shall be from boiler end to turbine building as the boiler side terminal point will be ready earlier. Utmost care shall be taken by highly experienced engineers / supervisors w.r.t. welding , preheat / post heat treatment of welds , NDT , free floating of lines before connecting to equipments.

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SPECIAL ERECTION PRACTICES: Following special erection practices will be followed,

1. Permanent flooring of boiler cavity prior to BES: NTPC to provide permanent flooring in boiler cavity (leaving the area for foundations under hold), around boilers and below ESP before start of erection. This will create a very convenient work atmosphere which will help us in maintaining good house keeping also it will avoid unnecessary re handling of material / temporary installations to facilitate flooring at later stage. It may be noted that the flooring should have load bearing capacity of 2.5 Kg/Cm2

2. Usage of passenger cum goods erection elevator: BHEL shall provide one no. of passenger cum goods elevator in each boiler which will be installed by our erection agency. This will transport people and gas cylinders to higher location which will help in effective supervision and higher productivity.

3. Usage of waste disposal chute: BHEL shall provide and erection agency will install one no. waste disposal chute in each boiler running vertically with branch in each floor.

4. Construction Power distribution system : BHEL shall ensure that erection agencies follows a standard construction power distribution system as explained below,

a) Agency for Main Boiler package: They will lay individual construction power cable from main Sub Station to DBs for individual welding generators booth at 5 locations as follows . These DBs will be provided with ELCB’s and the cables will be run underground before reaching boiler island and within the boiler island the cable will be run on cable trays (vertical run will be along column no. S12L&R)

o On ground floor between column box S11L-12L-6L-5L – will have provision for 10 welding m/cs - 200 Amps – from SS- 9 for U-3 from SS – 10 for U-4

o On boiler floor at 18M elevation between column box S11R-12R-6R-5R- will have provision for 10 welding m/cs – 200 amps – from SS –8 for U-3 from SS – 13 for U-4

o On boiler floor at 31M elevation between column box S11R-12R-6R-5R- will have provision for 10 welding m/cs – 200 amps – from SS-9 for U-3 from SS – 10 for U-4

o On boiler floor at 62 M elevation between column box S9L-10L-4L-3L- will have provision for 10 welding m/cs – 200amps – from SS-8 for U-3 from SS – 13 for U-4

o In pre assy yard – for 10 m/cs –200 amps – from SS-6 Tentative quantity of Cable 240sq.mm, three core, Al. cable – 2000 M

and cable tray 8” – 500M, DB (200amps) – 5 per boiler will be required.

All such DB’s will cater the need of power supply for Post Weld Heat Treatment also.

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Above locations of DB and booth installation and routing of Power cable for above are indicative, exact location shall be decided at site in consultation with NTPC.

Other than welding booth they will provide a power distribution board every after two floors with at least ten points, with standard industrial socket arrangement for miscellaneous use of hand tools and hand lamps. These boards will be connected with nearest DB of welding booth

b) Agency for ESP and ducting:

They shall lay construction power cable from main Sub station to DB for welding booth as follows

• At ground floor on LHS of ESP – 10 welding m/cs – 200 amps – from SS-9 for U-3 from SS – 10 for U-4

• At ground floor on RHS of ESP – 10 welding m/cs – 200 amps– from SS-8 for U-3 from SS – 13 for U-4

DBs will be provided with ELCBs. The cables will be run underground before reaching ESP island and within the ESP island the cable will be run on cable trays.

Tentative quantity of Cable 240sq.mm,three core ,Al. cable – 600 M and cable tray 8” – 150M No. of DB (200 amps )-2 per ESP will be required.

Above locations of DB and booth installation and routing of Power cable for above are indicative, exact location shall be decided at site in consultation with NTPC.

Other than welding booth they shall provide a power distribution board at least ten points one casing manhole door platform and one in pent house of each pass, with standard industrial socket arrangement for miscellaneous use of hand tools and hand lamps. These boards will be connected with nearest DB of welding booth.

c) Piping erection agency: They shall lay construction power cable from main Sub station (No. to DB for welding booth as follows:

• At 4.5 M in B- C bay near column 48- 10 welding m/cs - 200 amps + 1 induction heating m/c – 200 amps from SS-7 for both units.

• On boiler floor At 31 M near col. S7L will have provision for 10 welding m/cs – 200 amps. Induction Heating m/c will later be shifted from 62M along with power cable to 31M from SS-7 in U-3 and from SS-11 in unit-4

• On boiler floor at 62 M elevation between column box S9L-10L-4L-3L- will have provision for 10 welding m/cs - 200 amps - from SS-11 in both units + 1 induction heating m/cs – 200amps from SS-7 in both units.

The cables will be run underground before reaching boiler island and within the boiler island and in power house the cable will be run on cable trays . Vertical run in boiler will along cable-S7L

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It may be noted that Sub Station (SS) -7 shall be provided with back up DG set power supply to avert power failure to Induction Heating M/c.

Tentative quantity of Cable 200sq.mm three core al. cable – 2000 M and cable tray 8” – 500M, DB (200apms) - 5 per boiler will be required. Other than welding booth they shall provide a power distribution board at least ten points at least in five suitable locations, with standard industrial socket arrangement for miscellaneous use of hand tools and hand lamps. These boards will be connected with nearest DB of welding booth.

Above locations of DB and booth installation and routing of Power cable for above are indicative, exact location shall be decided at site in consultation with NTPC.

Location of substation and tentative routing of construction power cables is shown in Annexure-8

. 5. Winch locations : selected number of winch will be positioned as

follows by our erection agencies, Boiler Area:

a. 2 nos of 5MT winch on ground floor near S5L and near S5R b. 1no of 3 MT winch on boiler floor at 50M near column S4R c. 2 nos of 2MT winch on boiler floor at 75 M near column S4R and S4L ESP area: No winch is envisaged for ESP erection Piping area; a) One 3MT winch on LHS near column no. S7L b) One 3MT winch on LHS near column no. S7R

Operation of all these winches shall be controlled by Walkie Talkies from remote. Locations of the winches are indicative. Actual location can be decided at site.

6. Gas cutting sets: Our erection agencies shall use a set of one DA

cylinder and three oxygen cylinders mounted on trolley to be operated on ground floor. Also for transportation of such gas cylinders they shall use hand trolley.

7. Small Workshop: Our erection agencies shall install small workshop

containing drill m/c and bench grinder.

8. Erection Techniques: Following erection fixtures will be used for pressure part erection. this will ensure safe and faster erection of pressure part coils / panels,

a) Omega lugs: An attachment made of tubes and flat will

be welded to pressure part tubes will be used to hang and align pressure part headers to panel, panels to panels, panels to headers , hanger tube to coils , coils to coils etc. BHEL Trichy shall supply the lugs along with a

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load table. PSWR shall arrange for bolts. Location at winch the lugs to be welded shall be decided by engineers at site and shall be welded accordingly prior to lifting of components. This will help in quick erection of pressure part components and will facilitate easy alignment.

b) Lifting Tool for pressure part Coils: This is a hinged type clamp which develops grip due to self weight of the component being lifted.. This will be fabricated at site by our erection agency. This will be used to lift pressure part vertical coils of super heaters and re heaters.

c) Anti deformation frame for coils: The anti deformation frame will be fabricated ( considering actual size of coil ) at site and used for handling longer and heavy pressure part coils like Platen super heater , re heater front , super heater division panel , assembled LTSH / ECO coils , to avoid permanent distortion while lifting..

d) Floating Pulley system for LTSH and economizer coil erection: An arrangement of a ropeway and a floating pulley will be used for erection of LTSH and Economizer coils. This will reduce erection cycle time to great extent otherwise we would have lost lot of time in changing lifting arrangement after every few coils.

e) Erection method of Super heater hanger tubes: a very simple method of lifting SH Hanger tube will be used which will facilitate faster erection.

f) Temporary Rail for material feeding: A temporary rail line will be laid between boiler column no. S8-S9 through and through both boilers. Boiler pressure part materials like water wall panels and SH/RH Coils will be transported on to this rail with help of dip trolley. The rail will be laid on sleepers at 1m spacing. For transportation / dragging of boiler drum over the same rail continuous sleepers will be laid for two lengths of drum and rolled on. Requirement of material for this purpose will be as follows, Rail - 350 RMS Sleeper – 400 nos. (200 for normal material feeding + 200 will be used for drum dragging) Rail coupler / fish plate with fastener – suitable for 350 RMS rail Rail fixing clips – suitable for 350 RMS rail The portion of rail between two boilers will be made removable type ( in panel form ), so that the same can be temporarily removed to give access to other agency’s T&P movement.

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g) Temporary Urinal System : A header of 4”PVC pipe shall be run on column S7R with urinal pan connected to 10 floors minimum on boiler and with suitable underground pit arrangement.

MATERIAL FEEDING AND CRANE PARKING DURING BOILER ERECTION (major portion):

i) For main boiler supporting structure erection up to drum lifting :

Crane movement / Parking: within boiler cavity. Crane: FMC LS 248H 180MT from 1st to 3rd month, FMC LS 718 with ringer and 330’ boom and jib thereafter. Tentative Duration: from 1st to 5th month from BES of each unit. Material feeding: Unit-3- From Storage yard / pre assembly area by road though Unit-4 (either between mill bay-M row and boiler rear or between mill bay N row and ESP) Unit-4 – From Storage yard / pre assembly area on road ii) Pressure part erection: Crane: All erection will be done with help of winches. For unloading of material 75 MT crane will be located on RHS of each boiler. Tentative Duration: from 6th to 18th month from BES of each unit Material feeding: Unit-3- From Storage yard / pre assembly area by road though Unit-4 (either between mill bay-M row and boiler rear) then on rail to boiler cavity in case of first pass and through boiler rear in case of second pass. After drum lifting of unit- 4 is over the materials can be fed on temporary rail through boiler-4 Unit-4 – From Storage yard / pre assembly area on road then on rail to boiler cavity in case of first pass and through boiler rear in case of second pass. iii) For balance component like roof structure, silencer, duct, air pre heaters, fans (FD and PA) erection: Unit-3 LHS – Crane: Manitowoc –250MT (6th to 10th month ) , LS 248H (10th to 18th month) Tentative Duration: from 6th to 18th month from BES of unit-3 Material feeding: From Storage yard/ pre assembly area by road though Unit-4 (between mill bay-M row and boiler rear or between mill bay N row and ESP) Unit-3 RHS – Crane: FMC LS718 –350MT ( 6th to 12th month ) , Manitowoc –250MT ( 12 th to 18th month ) Tentative Duration: from 6th to 18th month from BES of unit-3

Page 128 of 175

Material feeding: From Storage yard/ pre assembly area by road though Unit-4 (between mill bay-M row and boiler rear or between mill bay N row and ESP) Unit-4 LHS – Crane: Manitowoc –250MT (6th to 18th month from BES of Unit-4) Material feeding: From Storage yard/ pre assembly area on road though Unit-4 (between mill bay-M row and boiler rear or between mill bay N row and ESP) Unit-4 RHS – Crane: FMC LS 718 – 350 MT (6th to 18th month BES of Unit-4) Material feeding: From Storage yard/ pre assembly area by road. iv)Mill erection: Unit-3 Crane: KH-500 Tentative Duration: 14th to 20th month from BES of unit-3 Material feeding: From Storage yard / pre assembly area on road though Unit-4 ( between mill bay-M row and boiler rear or between mill bay N row and ESP) unit-4 Crane : KH-500 Tentative Duration: 14th to 20th month from BES of unit-4 Material feeding : From Storage yard / pre assembly area on road v) ESP erection: Crane movement / Parking: all around ESP island Crane: 75MT , KH500 Tentative Duration: 1st to 18th month from ESP erection start of each unit Material feeding : Unit-3 – From Storage yard/ pre assembly area on road though Unit-4 (between mill bay N row and ESP & between ESP and ID fan)

Unit-4 From Storage yard/ pre assembly area on road

HOLDS ON CIVIL FOUNDATIONS / OTHER CONSTRUCTION :

a) Civil Foundations: S15L&R, S16L&R, S17, S18, S19L&R, S20L&R, S21, Mill bay M row columns 2nos at center and FD fan –B (RHS) in each boiler This is required for erection crane movement / parking inside boiler cavity and for ceiling girder pre assembly as explained in erection sequence.

Page 129 of 175

Hold lift – Hold shall be lifted as soon as crane is moved out after ceiling girders erection i.e. 5th month from boiler erection start. Agency to act: NTPC b) Other Construction: i) Mill bay ‘M’ & ‘N’ – row structure in each unit

This will be required for FMC entry / exit and parking during boiler structure erection in each unit.

Hold Lift: Hold shall be lifted as soon as crane is moved out after ceiling girders erection i.e. around 5th month from boiler erection start. Agency to act : NTPC

ii) Inter Connecting Duct / platform between boiler and mill bay in each unit :

This is required for moving out erection crane parked on LHS of boiler for erection of roof structure / fans / APH Hold Lift: the hold is planned to be lifted in 12 th to 14 th month from BES. Agency to act: BHEL

iii) Duct support structure between mill bay and ESP in each unit:

This will be required to facilitate crane movement for Mill heavier components and ESP erection. Hold lift: the hold is planned to be lifted progressively from 18th month from BES

Agency to act: BHEL iv) Duct support structure between ESP and ID fan:

This is required to facilitate crane movement for ESP erection and ID fan heavier component erection. Hold Lift: Hold is planned to be lifted progressively from 14th month from Boiler erection start.

Agency to act: BHEL v) Mill bay N row bracings :

This will be required to facilitate crane approach for erecting mill heavier components. The particular bracing items need to be hold will be decided at site in consultation with NTPC. Hold Lift: hold is planned to be lifted progressively from 14th month of BES Agency to act : NTPC

ADDITIONAL INPUTS (Not Envisaged Originally ) TO BE TIED UP :

By NTPC : a) Hold on foundations / structure as mentioned above b) Finished flooring in / around boiler island and below ESP c) Finished flooring / consolidated area for laying temporary rail By BHEL :

a) Temporary rail / sleepers etc. b) Bolt for omega lugs c) Temporary structure for drum lifting

Page 130 of 175

d) DESH Link temporary Dummy plates for non drainable HT e) DG set 500KVA for Induction Heating m/c

By erection agencies: a) Construction Power Distribution board b) Construction power cables c) Cable trays for above d) Portable Cutting Gas cylinder skid e) Cutting gas cylinder transportation trolley f) Small workshop g) Walkie talkies for winch control h) Urinal arrangement on boiler

TENTATIVE ERECTION PLAN : With all above we shall complete erection of boiler package as per the plan enclosed . ERECTION STRATEGY IS A BASIC DOCUMENT TO BE FOLLOWED HOWEVER FOLLOWING CHANGES ARE MADE BASED ON ERECTION FEEDBACKS AND SITE CONDITIONS:

1. Proposed temporary rail track between boiler columns no. S8-S9 through and through both boilers and up to pre assembly yard (refer annexure 6) was restricted to cover the boiler cavity of each boiler between column S8 & S9, since inter connection between two boilers and boiler 4 to pre assembly yard was obstructing the erection work of civil agencies.

2. For unloading of boiler drum for unit#3, 2 nos 75MT and 1 no 150MT (KH700) cranes were used instead of 1 no 150MT (LS248) and 250MT ( Manitovoc) cranes.

MASTER LIST OF QUALITY DOCUMENTS SL. NO.

DOC. TITLE UNIT DOC. NO. CUST. DOC. NO.

1. FQP FOR BOILER & AUX. (STORAGE & PRESERVATION

1230-001-QVG-G-1001

2. FQP FOR STG. & AUX. (STORAGE & PRESERVATION

1230-001-QVG-G-1031

3. BOILER STRUCTURE 1230-001-QVG-G-1002 4. PRESSURE PARTS 1230-001-QVG-G-1003 5. SOOT BLOWERS & FINE FITTINGS 1230-001-QVG-G-1004 6. VALVES (BOILER HPBP, TG & AUX) 1230-001-QVG-G-1005 7. FUEL FIRING SYSTEM 1230-001-QVG-G-1006

8. C & I OF STATION & BOILER & AUX. ST AND TG

1230-001-QVG-G-1046

9. COAL PULVERIZER 1230-001-QVG-G-1007 10. AIR PRE HEATER AND SCAPH 1230-001-QVG-G-1008 11. BOILER FANS (ID, FD & PA FANS) 1230-001-QVG-G-1009 12. IGNITOR, SCANNER & SEAL AIR FAN 1230-001-QVG-G-1010 13. SGWC PUMP 1230-001-QVG-G-1011

Page 131 of 175

SL. NO.

DOC. TITLE UNIT DOC. NO. CUST. DOC. NO.

14. ELECTROSTATIC PRECIPITATOR 1230-001-QVG-G-1012 15. DUCTS, DAMPERS, GATES & EXP. JOINTS 1230-001-QVG-G-1013 16. LINING AND INSULATION 1230-001-QVG-G-1014 17. PULVERISER FUEL PIPING 1230-001-QVG-G-1015 18. GRAVIMETRIC FEEDER 1230-001-QVG-G-1016 19. POWER CYCLE PIPING 1230-001-QVG-G-1017

20. STEAM TURBINE AND AUX. INCL. HEATERS, CEP & DEAERATOR

1230-001-QVG-G-1032

21. GENERATOR & AUX. 1230-001-QVG-G-1033 22. LP PIPING 1230-001-QVG-G-1081 23. BOILER FEED PUMP (MOTOR & TUR. DRIVE) 1230-001-QVG-G-1034 24. DRIVE TURBINE FOR BFP 1230-001-QVG-G-1035 25. BUSDUCT – 21 KV 1230-001-QVG-G-1058 26. MV BUS DUCT 1230-001-QVG-G-1059

27. TRANSFORMERS (GENERATOR, STATION, UAT, POWER)

1230-001-QVG-G-1060

28. SWITCHYARD 1230-001-QVG-G-1061 29. HT MOTORS 1230-001-QVG-G-1062 30. EFFULUENT TREATMENT SYSTEM 1230-001-QVG-G-1082 31. COMPRESSED AIR SYSTEM 1230-001-QVG-G-1083 32. VACUUM CLEANING SYSTEM 1230-001-QVG-G-1084 33. CONDENSATE POLISHING UNIT 1230-001-QVG-G-1085 34. CRANES – EOT & MISC. 1230-001-QVG-G-1086 35. FIRE PROTECTION SYSTEM 1230-001-QVG-G-1087 36. FUEL OIL SYSTEM 1230-001-QVG-G-1088 37. MILL REJECT HANDLING SYSTEM 1230-001-QVG-G-1089 38. PASSENGER CUM GOODS ELEVATORS 1230-001-QVG-G-1090 39. TANK & VESSELS 1230-001-QVG-G-1091 40. HVAC 1230-001-QVG-G-1092 41. AUX. TRANSFORMER – DRY TYPE 1230-001-QVG-G-1063 42. AUX. TRANSFORMER – OIL FILLED 1230-001-QVG-G-1064 43. CABLING (HT/LT, CONTROL CABLE) 1230-001-QVG-G-1065 44. DC SYSTEM 220/24 V BATTERY 1230-001-QVG-G-1093 45. BATTERY CHARGER 1230-001-QVG-G-1094 46. HT SWITCHGEAR 1230-001-QVG-G-1066 47. GENERATOR CIRCUIT BREAKER 1230-001-QVG-G-1067 48. DG SET 1230-001-QVG-G-1095 49. LT BUSDUCT 1230-001-QVG-G-1068 50. LT SWITCH GEAR 1230-001-QVG-G-1069 51. NEUTRAL GROUNDING SYSTEM 1230-001-QVG-G-1070 52. STATION LIGHTING SYSTEM 1230-001-QVG-G-1096 53. 132 KV CABLE LAYING & JOINTING 1230-001-QVG-G-1071 54. FLUE GAS CONDITIONING UNIT 1230-001-QVG-G-1018 55. FABRIC EXPANSION JOINT 1230-001-QVG-G-1019 56. DIVERTER DAMPER 1230-001-QVG-G-1020

57. CONDENSER ONLOAD TUBE CLEANING SYSTEM

1230-001-QVG-G-1036

58. TURBINE INSULATION 1230-001-QVG-G-1037 59. CONDENSATE STORAGE TANK 1230-001-QVG-G-1097

Page 132 of 175

LIST OF CE T&P AND SPECIAL EQUIPMENT T & P BEING PROVIDED BY BHEL :

SL. NO.

Description of Equipment

Qty. Range/ Capacity

Accuracy Work area

MM Package A Fire Retardant/PVC

Tarpaulins 100 10 x 8

B Erection Package 1. Telco TFC-280 Crane 1 75T NA Boiler Erection

2. Telco TFC-280 Crawler Crane

1 75T NA ESP-1

3. Telco 955 ALC Crawler Crane

1 75T NA Boiler

4. Telco 955 ALC Crawler Crane

1 75T NA BOP

5. Telco 955 ALC Crawler Crane

1 75T NA ESP-II

6. Link-Belt LS-718 with Ringer (FMC)

1 325T NA Boiler

7. Telco KH-500 Crawler Crane

1 100T NA Mills / Rot. M/C.

8. Manitowoc M-250 T Truck Crane

1 250T NA Str. / Roof top.

9. Passenger Cum Goods Lift 1 T

1 1T NA Boiler – I

10. Passenger Cum Goods Lift 1T

1 1T NA Boiler – II

11. E/O Pipe Bending M/c.

2 4” NA Boiler / Piping

12. Electric Scraper 2 NA Blr./PCP/TG

13. Hydraulic Test Pump 2 600 Kg./CM2

NA Boiler

14. Hydraulic Test Pump 1 450 Kg. NA Boiler/PCP

15. Induction Heating Equipment

6 125 KW/3 MHZ

NA Boiler / PCP

16. Fogging M/c. 1 NA ESP 17. E/O Winch with rope 2 15T NA Boiler Drum

18. Multi Sheave Pulley Block 15 Sheave.

4 300/200T NA Boiler Drum

19. Single Sheave Pulley Block

10 10T NA Boiler

20. Acid Cleaning Pump with control Panel

7 200TPH NA Boiler

21. Huck Bolting M/c. 4 NA ESP.

Page 133 of 175

RIHAND UNIT-3 & 4

0

10000

20000

30000

40000

50000

60000

70000

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33

MONTHS

MT

BOILER ERECTION MONTHS CUMU U-3CUMU U-4 CUMU U-3+4

Page 134 of 175

LOCATION OF CEILING GIRDER PRE-ASSEMBLY

12 L

(L)

(R)

CEILING GIRDER - B

CEIL

ING

GIR

DER

- D

CEIL

ING

GIR

DER

- E

CEIL

ING

GIR

DER

- C

1 R

6 L

5 L

4 L

3 L

2 L

1 L

6 R

5 R

2 R

3 R

4 R R10

12 R

11 R

7 R

13 R 13 L

7 L

8 L

9 R

10 L

11 L

18

8 R

9 R

( R

)

( L)

( R

) (

L)

Page 135 of 175

C.G. - A C.G. - B C.G. - C C.G. - D 2ND PLACE C.G. - E C.G. - F 3RD PLACE 1ST PLACE 4TH PLACE ‘’ OPTIMUM POSITION OF FMC CRANE WITH 330 ft. BOOM FOR TOTAL GIRDERS, COLUMN TOP PIECESS & SILENCER STRUCTURES ERECTION.”

1 R

6 R

5 R

2 R

3 R

4 R

13 R 13 L

22.5 M22.5 M

22.5 M

22.5 M

22.5 M

22.5 M

12 L 6 L

5 L

4 L

3 L

2 L

1 L

10 R

12 R

11 R

7 R 7 L

8 L

9 R

10 L

11 L

8 R

9 R

18

Page 136 of 175

KEY PLAN 14 R 14 L 15 R 15 L 16 R 16 L

12 L

1 R

6 L

5 L

4 L

3 L

2 L

1 L

6 R

5 R

2 R

3 R

4 R 10 R

12 R

11 R

7 R

13 R 13 L

7 L

8 L

9 R

10 L

11 L

18

8 R

9 R

26 R 26 L

24 L 24 R 29 L

27 L

29 R

28 R

27 R 19 L

20 L

21

22 L 22 R

19 R

20 R 23 R 25 R 23 L 25 L 28 L

Page 137 of 175

KEY PLAN OF BOILER COLUMNS

1 R

6 R

5 R

2 R

3 R

4 R

13 R 13 L

12 L 6 L

5 L

4 L

3 L

2 L

1 L

10 R

12 R

11 R

7 R 7 L

8 L

9 R

10 L

11 L

8 R

9 R

18

Page 138 of 175

PRE ASSEMBLY OF COL. S 18 (6th & 7th pcs) WITH 4 nos VERTICAL POST, TIE BEAMS & VERTICAL BRACINGS

1812R 12L

+ 61.068 EL

+ 73.768 EL

+ 79.768 EL

+ 88.450 EL CEILING GIRDER - F CEILING GIRDER - F

POST POST

+ 67.468 EL

Page 139 of 175

PRE ASSEMBLY OF S 16 L&R WITH TIE BEAMS & BRACINGS

+9.718

+23.268

+37.518

16 R 16 L 10 L 10 R 4 R 4 L

I st

II nd

Page 140 of 175

PRE ASEEMBLY OF 4 nos VERTICAL BRACING WITH TIE BEAM

12 R 18 12 L

+ 9.718 EL

+ 23.268 EL

+ 37.518 EL

Page 141 of 175

PRE ASSEMBLY OF 3 nos VERTICAL BRACING WITH TIE BEAMS

12 R 18 12 L

+ 38.550 EL

+ 44.818 EL

+ 48.318 EL

Page 142 of 175

PHOTO

GALLERY

Page 143 of 175

RIHAND STAGE –II DEDICATION TO THE NATION

Mr Sushil Kr Shinde, Honourable Cabinet minister of power,

Government of India dedicated Rihand STPP (Stage-II 2X500MW) to the nation on 09.08.2006. On this occasion Mr Mulayam Singh Yadav

Chief Minister of UP was also present.

Page 144 of 175

EVOLUTION OF 2X500MW RIHAND STAGE-II

16.06.2003

24.11.2003

06.01.2004

28.01.2004

12.09.2004 18.07.2005

Page 145 of 175

20.09.2005 08.03.2006

06.04.2006 14.04.2006

03.06.2006 16.12.2006

Page 146 of 175

TG HALL

GENERATOR SIDE TURBINE SIDE

Page 147 of 175

BOILER#3

13.05.2003

12.11.2003

11.12.2003 26.07.2005

Page 148 of 175

BOILER DURING ERECTION

BOILER PASS ‘A’

BOILER PASS ‘B’

DRUM FLOOR

Page 149 of 175

BOILER DRUM FLOOR

DRUM LIFTING 29.03.2003 DRUM LIFTING 11.07.2003 UNIT#3 UNIT#4

Page 150 of 175

UNIT#4 BOILER DRUM BEFORE LIFTING

BOILER DRUM OF UNIT#4 LIFTED IN THE PRESENCE OF MR ANANT

GEETE, HONOURABLE POWER MINISTER, GOVT. OF INDIA

Page 151 of 175

ID FAN ERECTTION

DUCT TO CHIMNEY

MILL BASE BEING ERECTED AIR PRE HEATER

BOTTOM RING HEADER CEILING GIRDER BEING LIFTED

Page 152 of 175

BOILER#4

13.05.2003 CEILING GIRDER ERECTION

11.12.2003 18.02.2004

Page 153 of 175

17.03.2005 05.03.2006

Page 154 of 175

ESP DURING ERECTION

ESP#3

13.05.2003 18.02.2004

ESP#4

13.05.2003

18.02.2004

ESP FROM BACK SIDE ESP TOP VIEW

Page 155 of 175

ACID CLEANING ARRANGEMENTS OF BOILER

DM WATER & ACID STORAGE TANKS

ACID PUMPS

BOILER FILL PUMPS

Page 156 of 175

80 MVA TRANSFORMER UNIT#3

ERECTION STAGE BUS DUCT ERECTION

80 MVA STATION TRANSFORMER READY FOR CHARGING

Page 157 of 175

214 MVA GENERATOR TRANSFORMERS (3 NOS) WITH 80MVA STATION TRANSFORMER IN CHARGED CONDITION

220V DC BATTERY ROOM 24V DC BATTERY ROOM

Page 158 of 175

ELECTRICALLY OPERATED TOWER CRANES

EOT FOR UNIT#3 UNDER LOAD TEST (19.06.2003)

EOT FOR UNIT#4 READY FOR LOAD TEST (19.01.2004)

Page 159 of 175

COOLING WATER LINE DURING ERECTION

CW PIPE AT Y PIECE UNIT#3

ALL 4 LINES NEAR UNIT#4

CW PIPE – EAST NALA CW PIPE AFTER Y PIECE

CW PIPE AT Y PIECE UNIT#4 CW PIPE IN CT AREA

Page 160 of 175

24.11.2003 15.10.2003

AUXILIARY COOLING WATER

ACW PIPING START ACW ARRANGEMENT

Page 161 of 175

MAIN TG EQUIPMENTS

TOP OF TG HALL FIRST SYNCHRONIZATION #3

UNIT#3 01.02.2005 UNIT#3 19.07.2005

UNIT#4 19.07.2005 TG HALL

Page 162 of 175

CONDENSER ERECTION

BOTTOM PLATE FABRICATION

CONDENSER TUBING

TUBE PLATES LPH-1 ERECTION

TURBINE ERECTION

LPT ROTOR LP OUTER CASING

Page 163 of 175

BEARING PEDESTALS PLATE HEAT EXCHANGER

HP HEATER ERECTION

HP HEATERS IN POSITION HP HEATER PIPING

BOILER FEED LINE

BFD LINE ERECTION FLUSHING ARRANGEMENT

Page 164 of 175

CRITICAL PIPING FROM BOILER CW PIPE FROM CONDENSER

TANKS

CONDENSATE STORAGE TANKS LDO TANK

Page 165 of 175

GENERATOR STATOR LIFTING

ARRIVAL OF STATOR PORTAL CRANE INSIDE TG HALL

STATOR LIFTING IN PROGRESS PORTAL CRANE OUTSIDE HALL

Page 166 of 175

GENERATOR EXCITER ERECTION

DURING COMMISSIONING

SMOKE OF INITIAL LIGHT UP FIRE FROM BOILER PEEP HOLE

MD BFP MOTOR HEATING ASH BUILD UP IN ESP DURING INITIAL COAL FIRING

Page 167 of 175

SITE CONDITIONS DURING RAINY SEASONS

ESP BACK SIDE

CW LINE IN WATER

BOILER#3 LEFT SIDE MAIN APPROACH TO BOILER

Page 168 of 175

BOILER IN WATER

BOILER#3 APPROACH BETWEEN ESP & BOILER

CRANE MOVEMENT DIFFICULT DURING RAINS

Page 169 of 175

BETWEEN BOILER & BUNKER BAY TRANSFORMER BAY APPROACH

Page 170 of 175

DELAYED CIVIL FRONTS

LEFT BUNKER#4 ON 08.04.2005 RIGHT

BUNKER#3 RIGHT 08.04.2005

BUNKER#4 RIGHT 18.07.005

CONDENSER#4 FDN

APPROACH PROBLEM (01.04.2004)

CEP FDN#3 IN WATER 15.10.2003

Page 171 of 175

COVERING OF TG #3 HALL 21.01.2004 TG DECK # 3 WITHOUT APPROACH 13.05.2003

TG DECK#4 APPROACH 19.02.2004

TG HALL #4 COVERING 31.01.2004

CPU BUILDING 12.09.2004 COMPRESSOR ROOM – NO COVERING

Page 172 of 175

TG HALL IN WATER 01.04.2004 FDNS BACK SIDE OF ESP#4

SERVICE BUILDING ON 06.03.2006

Page 173 of 175

BUNKER BAY BEAMS DAMAGE DUE TO ACCIDENT OF CIVIL AGENCY’S CRANE KH-700 (CRANE LEFT LOAD FROM HEIGHT 70 MTR), ITS JIB

ALSO DAMAGED

TATA TFC-75 TOPPLED WHILE LIFTING THE CONTAINER

Page 174 of 175

CIVIL AGENCY DISPOSED OFF THE LEFT OUT EXPLOSIVES BELOW THE CABLE TRESTLE FOR COOLING PUMP HOUSE/

COOLING TOWER AREA, RESULTED EXTENSIVE DAMAGE TO POWER/ CONTROL CABLES ON 15.06.2005

Page 175 of 175

OFF SITE PACKAGES

COOLING TOWERS BY M/S PAHARPUR

COAL HANDLING PLANT BY ISG BANGALORE

400KV SWITCH YARD BY TBG BHOPAL