Unit Overhaul

7/31/2019 Unit Overhaul

1/23

NTPC/VINDHYACHAL

UNIT OVERHAULS

6X210 MW & 4X500 MW UNITSOF

VINDHYACHAL SUPER THERMAL POWER PROJECT,

NATIOANAL THERMAL POWER CORPORATION LTD.,P.O. : VINDHYANAGAR, DISTT.: SIDHI (M.P.), PIN:486885


2/23

NTPC/VINDHYACHAL

UNIT OVERHAULS PHILOSOPHY

210 MW ( LMW ) UNITS

TYPE OF OVERHAUL MAIN AREAS IDENTIFIED PERIOD OF FREQUENCY

FOR OVERHAUL OVERHAUL

A BOILER & AUX. 20 DAYS EVERY YEAR

TUR. BRGS. INSP.

X BOILER & AUX. 21 DAYS EVERY 3rd YEAR

GENERATOR ROTOR THREAD OUT

D BOILER & AUX. 35 DAYS EVERY 6th YEAR

ALL TURBINE CYLINDERS O/H



3/23

NTPC/VINDHYACHALUNIT OVERHAULS PHILOSOPHY

500 MW ( KWU ) UNITS

TYPE OF OVERHAUL MAIN AREAS IDENTIFIED PERIOD OF FREQUENCY

FOR OVERHAUL OVERHAUL

E BOILER & AUX. 15 DAYS EVERY YEARTUR. BRGS. INSPECTION

F BOILER & AUX. 25 DAYS EVERY 3rd YEAR

LP TURBINE INSPECTION

G BOILER & AUX. 35 DAYS EVERY 8th YEAR

HPT / IPT O/H



4/23

NTPC/VINDHYACHAL

UNIT OVERHAULS - PHILOSOPHY

210 MW ( LMZ ) UNITS

TO CONTROL THE O&M COST FOLLOWING ARE THE ACTIONS:

SEQUENCE OF O/H FOR THE STATION ARE SO ADJUSTEDTHAT NOT MORE THAN TWO MAJOR O/Hs (TYPE D)

TAKEN UP IN A YEAR.

WHENEVER TWO MAJOR O/H COMMENCES IN A STATION

IN A YEAR, SITE TAKES DECISION, DEPENDING ON BOILERCONDITIONS, TO RESTRICT THE O/H DURATION OF BOILER

SUITABLY TO 17 DAYS AND 15 DAYS FOR 200 MW AND 500

MW UNITS RESPECTIVELY.


5/23

NTPC/VINDHYACHAL

OBJECTIVES OF UNIT OVERHAULS

TO MAXIMIZE PLANT AVAILABILITY

TO MINIMIZE MAINTENANCE COST THROUGH

OPTIMIZATION OF RESOURCE UTILIZATION

TO CREATE SAFETY IN WORK, EQUIPMENT AND

ENVIRONMENT


6/23

NTPC/VINDHYACHAL

AIMS OF UNITS OVERHAUL

TO IMPROVE AVAILABILITY OF EQUIPMENT & SYSTEM

TO IMPROVE QUALITY & INSPECTION OF MAINTENANCE JOBS

TO IMPROVE MONITORING & REPORTING OF O/H PROGRESS

TO REDUCE OVERHAUL DURATION

TO IMPROVE THE RE-COMMISSIONING INTERFACE

TO PROVIDE A RECORD OF WORK CARRIED OUT

TO MINIMIZE ISOLATION RESTRICTIONS

TO REDUCE DUPLICATION OF ENGINEERING EFFORTS TO ENSURE STATUTORY REQUIREMENT OF BOILER LICENCE


7/23

NTPC/VINDHYACHAL

CATEGORIZATION OF

UNIT OVERHAUL PROCESS

PLANNING

UNIT SHUT DOWN COOLING DOWN OF MACHINES

DISMANTLING

INSPECTION FOR CONDITION

REPAIR & RECTIFICATION

ASSEMBLY

TESTING & INSPECTION

REVIVAL OF EQUIPMENT & SYSTEM

REVIVAL & RECOMMISSIONING OF UNIT


8/23

NTPC/VINDHYACHAL

IMPROVEMENT AREAS IDENTIFIED

BARRING GEAR STOPPAGE TIME CONDENSER VACUUM GENERATOR AIR TIGHTNESS TEST TIME AIR INGRESS IN BOILER

SCOPE OF WORK OF GENERATOR OVERHAUL ELECTRICAL TESTING TIME REVIVAL TIME OF UNIT AFTER UNIT OVERHAUL-HFO

CONSUMPTION SCOPE OF IN SITU TESTS DURING UNIT OVERHAUL SCAFFOLDING ERECTION & DISMANTLING TIME PERCENTAGE AREA OF TUBES COVERED FOR D-METERING BOILER SAFETY VALVES SETTING TIME

ULTIMATELY LEADING TO IMPROVEMENT IN PLANT

AVAILABILITY, RELIABILITY & REDUCTION OF O&M COST


9/23

NTPC/VINDHYACHAL

PLANNING OF UNIT OVERHAULS


10/23

NTPC/VINDHYACHAL

CLASSIFICATION OF PLANNING ACTIVITIES

PRE OVERHAUL ACTIVITIES

DURING OVERHAUL ACTIVITIES

POST OVERHAUL ACTIVITIES


11/23

NTPC/VINDHYACHAL

PRE OVERHAUL ACTIVITIES

PLANNING & APPROVAL OF EIGHT YEAR ROLLING PLAN

OF UNIT OVERHAULS

PLANNING & APPROVAL OF NEXT FINANCIAL YEAR PLANFOR UNIT OVERHAULS

PLANNING & APPROVAL OF MAJOR WORKS TO BE

CARRIED OUT DURING UNIT OVERHAULS

IDENTIFICATION, REQUIRED QUANTITY PROJECTIONAND REVIEW OF STATUS OF CONSUMABLES ( STOCK

ITEMS) ON MONTHLY BASIS FOR UNIT OVERHAULS


12/23

NTPC/VINDHYACHAL

CONTD

IDENTIFICATION OF CRITICAL MATERIALS REQUIRED

FOR UNIT OVERHAULS AND REVIEW ON MONTHLY BASIS.

PREOVERHAUL MEETING FOR REVIEW OF CONSTRAINTS& PREPAREDNESS INVOLVING ALL.

PRE OVERHAUL CONDITION MONITORING REPORT

PREOVERHAUL UNIT SURVEY

UNIT OUTAGE ANALYSIS FROM LAST OVERHAUL

FEED BACK OF UNIT FROM FIRST SYNCHRONIZATION

REVIEW OF STATUS & COORDINATION OF WELDING

SUPPLY, LIGHTING, LIFTS, HOISTS, CRANES ETC.


13/23

NTPC/VINDHYACHAL

CONTD

PAST OVERHAULS AT A GLANCE (HISTORY OF UNITS)

PREPARATION OF MILESTONES (PLANNED)

COMPILATION OF UNIT DEFECT LIST

PRE OVERHAUL SPRAY VALVES CHARACTERISTICS

WORK REQUIRED TO BE CARRIED OUT AS PER

OPERATION REQUIREMENT

EFFICIENCY REQUIREMENT

CHEMISTRY REQUIREMENT

TRIPPING COMMITTEE RECOMMENDATIONS

C&I REQUIREMENT


14/23

NTPC/VINDHYACHAL

CONTD

BOILER TUBE LEAKAGE COMMITTEE RECOMMENDATIONS

OS RECOMMENDATIONS

CONDITION MONITORING GROUP RECOMMENDATIONS

SAFETY REQUIREMENT

R&M REQUIREMENT

PREPARATION OF: PTW & CLEARANCE BOOKS FOR BOILER & AUX.

PTW & CLEARANCE BOOKS FOR TG & AUX.

CLEARANCE & RECOMMISSIONING BOOK FOR VALVES,

DAMPERS, IGVs, SOOT BLOWERS & LRSBS


15/23

NTPC/VINDHYACHAL

CONTD...

CHECK SHEET FOR MOTOR TRIALS, EQUIPMENT

RECOMMISSIONING & PROTECTION CHECKING

CHECK SHEET FOR VALVES REQUIRED FOR CONDENSER

FLOOD TEST

CHECK SHEET FOR VALVES REQUIRED FOR BOILER

HYDRO TEST

COMMUNICATION LOG BOOK


16/23

NTPC/VINDHYACHAL

DURING OVERHAUL ACTIVITIES

PREPARATION OF DISPLAY BOARD FOR

COMMUNICATION OF OVERHAUL PLANNING

COORDINATION IN ISSUE OF PERMITS

MONITORING OF WORK PROGRESS / COMPLETION

COORDINATION OF REGULAR UNIT OVERHAUL MEETING

AT 5:30 PM IN O&M CONFERENCE HALL

PREPARATION & DISTRIBUTION OF RECORD NOTES

FEEDBACK TO WRHQ & CC-OS FOR WORK PROGRESS


17/23

NTPC/VINDHYACHAL

MONITORING & REVIEW OF CRITICAL VALVES STATUS AS

PER CHECK SHEETS REQUIRED FOR CONDENSER FLOOD

TEST & BOILER HYDRO TEST

MONITORING & REVIEW OF CLEARANCES AVAILABLE &

RECOMMISSIONING PROGRESS ( MOTORS TRIALS /

EQUIPMENT TRIALS)

COORDINATION IN

FURNACE AIR TIGHTNESS TESTS

CONDENSER FLOOD TESTS

BOILER HYDRO TESTS


18/23

NTPC/VINDHYACHAL

POST OVERHAUL ACTIVITIES

PREPARATION OF UNIT-WISE UNIT OVERHAUL REPORTIN BOOK FORM HARD COPY FOR LIBRARY & ISO

PREPARATION OF UNIT OVERHAUL REPORT IN CD-

FORMAT POST OVERHAUL REVIEW OF WORKS PLANNED AND

ACTUALLY COMPLETED.

POST OVERHAUL REVIEW OF IMPROVEMENT IN

PARAMETERS & EFFICIENCY POST OVERHAUL PLAN Vs ACTUAL DEVIATION SHEET


19/23

NTPC/VINDHYACHAL

PROCESS IMPROVEMENTS

BOILER EXTERNAL WATER WASHING WAS CAUSINGDAMAGE TO INSULATION AND DELAY IN START OFOVERHAUL ACTIVITIES, DRY BOILER CLEANINGSTARTED.

QUICK ERECT SCAFFOLDING IS BEING USED FOR BOILERINTERNAL CLEANING & INSPECTION

HIGH PRESSURE WATER JET CLEANING IS BEING DONEFOR BOILER TUBES

ALL PA FANS & MILL MOTORS VIBRATION MEASUREMENTALSO STARTED DURING UNIT OVERHAULS

ALL HT MOTORS TRIAL RUN IS BEING TAKEN FOR 8 HRSAND LT MOTORS FOR 4 HRS


20/23

NTPC/VINDHYACHAL

PROCESS IMPROVEMENTS

CONDENSER TUBE CLEANING IS BEING DONE USINGCONCO BULLETS

INVOLVEMENT OF FQA IS INCREASED IN MAIN TURBINE &GENERATOR AREA

BOILER DRUM FILLING USING HOT WATER STARTED

BOILER TUBES D-METERING SCOPE INCREASED UPTO25000 LOCATIONS.

24-VOLT HAND LAMPS ARE BEING USED

PREOVERHAUL / DURING OVERHAUL SAFETY SURVEYBEING CARRIED OUT


21/23

NTPC/VINDHYACHAL

ADDITIONAL RESPONSIBILITIES

DRAWING SECTION: O&M DRAWING SECTION IS PIONEERIN DEVELOPMENT OF DRAWINGS IN AUTO CAD.MANPOWER: TWO DRAFTMENTRAINED IN AUTO-CAD

PRINT ROOM: O&M PRINT ROOM COPE UP THE DAY TODAY REQUIREMENT OF

PHOTCOPYING, CYCLOSTYLLING & AMMONIA PRINTINGOF DRAWINGS REQUIRED FOR INDENTING PURPOSES.MANPOWER: ONE ATTENDANT

DISPLAY ROOM: O&M DISPLAY ROOM LOCATED ATSERVICE BUILDING O MR IS BEING MAINTAINED AND

UPDATED REGULARLY


22/23

NTPC/VINDHYACHAL LONG TERM PLANNINGCONSTRAINTS

UNIT OVERHAUL REPORTS: INSPITEOF ALL BEST POSSIBLEEFFORTS, PROBLEM IS BEING FACED TO GET THE FEEDBACKFROM OTHER DEPARTMENTS FOR THE JOBS COMPLETED,MEASUREMENTS TAKEN AND EXPENDITURE INCURRED

DURING UNIT OVERHAULS, WHICHCAUSES DELAY INCOMPILATION OF UNIT OVERHAUL REPORTS.

OVERHAUL COST: PRESENTLY IT IS DIFFICULT TO GET THEFINANCIAL DATA i. e. UNIT OVERHAULS COST (THE

EXPENDITURE INCURRED DURING RESPECTIVE UNITOVERHAULS). CONTINUOUSLY THESE DATA ARE BEINGASKED BY CC & WR.

ISSUE OF MATERIALS: MATERIALS PROCURRED FOR UNITOVERHAULS MUST BE TAGGED BY STORES AND NOT TO BE

ISSUED TO ANY OTHER DEPARTMENT WITHOUT CONSENT.


23/23

NTPC/VINDHYACHAL

THANK YOU

Documents

Unit Overhaul