Operation And Maintenance Of Power Plant

Permit to work system Different types

of Maintenance of Power Plant and its cost effectiveness Maintenance Planning Power Plant Operation

Permit to Work System PTW

is a printed form and issued to employee before they may work on specified equipment. Objective is to ensure safety of employee PTW is Guarantee of Safety

Steps/ Arrangement while issuing PTW  PTW

should be issued only against the presentation of an isolation request by maintenance Department Except in case of emergency.  Person presenting himself to collect PTW should be fully familiar with the job and details of work to be done  All Copies of PTW must be signed both at Receipt and Clearance  Receipt and Clearance signature must be made in presence of Shift Charge Engineer/ Unit incharge  PTW should be signed for clearance by the person who signed for receipt

Steps/ Arrangement while issuing PTW …….contd  Whenever a job is permanently transferred

from one person to another, the permit should be cancelled and reissued.  The PTW is cancelled and reissued when change in isolation become necessary  Work on medium/ low voltage equipments should be done when they are dead.  At least two isolation should be in service in case of electrical Permit  “Do Not Operate” caution board should be put on desk on control station of equipments under PTW

Steps/ Arrangement while issuing PTW …….contd  An emergency Job Card should be opened by

operation department giving details of work in case of Emergencies  Operation representative has to deliver the equipment to maintenance section ensuring all safety  Operation representative must ensure that job has been carried out properly before taking back the PTW.  Operation representative must ensure that there is no danger before charging the equipment/ System

At Work Maintenance person should must ensure

that PTW has been issued for their own safety It is responsibility of all persons on site to ensure that they do not start work on equipments for which a PTW is necessary untill PTW is issued.

Role of Operation Engineer Safety of equipment Safety of Persons Generation of Electricity at economic cost Keeping generation within the declared

schedule Start up and shut down of equipments in safe and systematic manner

Role of Operation Engineer ….Contd. Maintaining the parameters within

prescribed limit Physical Inspection of equipment to observe Noise, Vibration etc. Prompt Decision Making Cost Effectiveness in Present Scenario (ABT - UI)

Grid Discipline Grid Discipline is given a priority in ABT Incentive and penalty in form of UI to

maintain Grid Frequency Penalty when actual generation is less than scheduled Incentive when actual generation is more than scheduled generation when frequency is less  It is a new challenge for operation engineer

U I Rate  Each

0.02 Hz step is equivalent to 8.0 paise/kwh in the range of 49.8-50.5 Hz  Penalty is 18.0 paise/kwh in the range of 49.049.8 Hz for each 0.02 Hz step  Incentive is 18.0 paise/kwh in the range of 49.8-49.66 Hz for each 0.02 Hz step below 49.66 is fixed  UI rate is capped at 49.66 when actual generation exceeds the scheduled generation  UI rate goes up to Rs 10.0 per Kwh when actual generation is below scheduled generation

STEPS Pre Start Up/Light Up Checks Starting Auxiliaries Light Up Rolling and Soaking Synchronization Loading Off Loading Shut Down

Type of Start Cold Start Hot Start

Auxiliaries

Boiler Auxiliaries  Milling

System  Draft System  ESP

Turbine Auxiliaries Pumps  Feed Heaters  Dearator 

 Generator Auxiliaries  Seal

Oil System  Hydrogen Cooling System  Stator Water Cooling System

START UP PROCEDURE FOR STAGE-I AND II UNITS 0. RELAY RESETTING. 1. START ID AND FD 1.1 Deaerator tank Heating/AS-57 etc 1.2 SCRAPPER/SLAG CRUSHER IN SERVICE 1.3 BIGGER SIZE OIL GUN TIPS 2. BOILER LIGHTUP 2.1 START PA FANS : FLUE GAS TEMP>350 2.11 START MILLING SYS AND PC FEEDER 2.2 START SEAL AIR FAN 3. MAINTAIN TOTAL AIR FLOW >30% 4. DRUM PR =5 KSC CLOSE BOILER VENTS

START UP PROCEDURE FOR STAGE-I AND II UNITS

5. CLOSE SH HDR DRAINS 6. OPERATE BOILER LPDS AT 10 KSC DRUM PRESS. 6.1 START COND VACC PULLING 6.2 CHARGE SEALING STEAM ; 150 mm Hg Take GSC-1 7. CHARGE HP/LP BYPASS/APRDS MS 30 KSC/330 CELSIUS 7.1 READY RESPECTIVE BAY FROM S/YARD 7.2 UAT BREAKERS SERVICE REMOTE 7.3 AC/DC FIELD FLASHING SUPPLIES ON 8. TPL HEATING DRAINS OPEN 8.1 STG-I MS-9,10 OR BYPASS ESV 60% OPEN 8.2 STG-II LOCK IV OPEN ESV=60% MS-5,6 OPEN

START UP PROCEDURE FOR STAGE-I AND II UNITS 9. STOP TPL HEATING/NORMALISE LOCKING 10. MANNING OF SEAL OIL SYSTEM 10.1 LINEUP FOR FLANGE/STUD HTNG 10.2 OPEN HPC AND IPC CYL DRAINS 11. START ROLLING 500 RPM 12. ROLLING 1100 RPM 13. ROLLING 3000 RPM 13.1 STOP SOP 13.2 START CW BOOSTER PUMP

START UP PROCEDURE FOR STAGE-I AND II UNITS 14. SYNCHRONISE THE UNIT 15. OPEN MS-1,2 OR 9,10 AND ISOLATE HP/LP BYPASS OR PRDS 15.1 RAISE LOAD TO 50 MW : TAKE UATS IN SERVICE 15.2 OPEN AS-30 STG-I 15.3 CHARGE LPHS START DRIP PUMP STG-I 15.4 NORMALISE DEAERATOR EXT –IN ;HTNG –STOP 15.5 CLOSE ALL TURBINE SIDE DRAINS 15.6 PUT ALL PROT IN SERVICE

START UP PROCEDURE FOR STAGE-I AND II UNITS 16. START SECOND BFP RAISE LOAD 17. CHARGE HPHS AT 100 MW 18. TAKE AS-49/11 ATA IN SERVICE 19. CHARGE ESP ZONES 20. ISOLATE FLANGE/STUD HEATING/STARTING EJECTOR

PLANNED SHUTDOWN OF STAGE-1 UNITS 1. 2. 3. 4. 5. 6. 7.

REDUCE THE LOAD ALONGWITH OIL GUNS TO 30-35 MW ISOLATE LPHs FROM STEAM AND WATER SIDE STOP DRIP PUMP UAT CHANGEOVER /MAINTAIN PC LEVEL TRIP THE UNIT AROUND 20 MW/MS TEMP=480-450. START SOP .LATER ON C/O TO AC LOP AND AC SEAL OIL PUMP CLOSE AS-30 SPINDLE LEAKOFF TO D/A

PLANNED SHUTDOWN OF STAGE-1 UNITS PUT TG SET ON B/GEAR. CLOSE SYPHON FILLING V/V KILL THE COND VACUUM.CLOSE AS-9 AND D/A DOME HEATING V/V 3. 4. 5.

BOILER LPD OPERATION AT 10 KSC DRUM PRESS RACK OUT UAT BRKR ,OPEN BAY ISOLATOR SWITCH OFF AC/DC FIELD FLASHING SUPPLIES

PLANNED SHUTDOWN OF STAGE-1 UNITS 2. 3. 4. 5. 6.

TAKE LOCAL TG SET ECC. START TSI LOGGING SWITCH OFF EP ZONES CLOSE FO-1 ISOLATE 11ATA V/V AND OPEN DRAINS OPEN SH/DRUM VENTS AND STOP SLAGCRUSHERS.

PLANNED SHUTDOWN OF STAGE-2 UNITS      

REDUCE LOAD AS FAR AS POSSSIBLE WITH 4 MILL W/OUT OIL NORMALISE TURBINE SEALING (IF ADJUSTED) CONTROL TSI PARAMETERS CLOSE ALL FUEL /AUX AIR DAMPERS TAKE OIL AND CUT OFF LOWER MILLS TO MAINTAIN MS TEMP REDUCE LOAD TO 100 MW

PLANNED SHUTDOWN OF STAGE-2 UNITS       

ISOLATE HPH HEATERS. DO UAT CHANGEOVERS MAINTAIN TOTAL AIR FLOW> 30 % STOP ONE FD TO CONTROL OXYGEN/FURNACE HUNTING REDUCE LOAD FURTHER TO 30-40 MW .STOP ONE BFP TRIP THE UNIT.START SOP.CHECK COASTING TREND OF TG ISOLATE EXTRACTIONS .Give tripping commands to tripped brkr ENGAGE B/GEAR TAKE LOCAL TG ECC

PLANNED SHUTDOWN OF STAGE-2 UNITS        

KILL THE COND VACUUM..CLOSE AS-61 BOX UP THE BOILER. SWITCH OFF EP ZONES. OPERATE BOILER LPD AT 15 KSC DRUM PRESS OPEN BOILER/SH VENTS AT 5 KSC DRUM PRESS RACK OUT UAT BRKRS AND OPEN BAY ISOLATOR SWITCH OFF AC/DC FIELD FLASHING SUPPLY STOP LDO PUMP. ISOLATE 16 ATA AND OPEN DRAINS START LOGGING OF TSI /DRUM METAL TEMP

PLANNED SHUTDOWN OF STAGE-2 UNITS PRECAUTIONS: BOILER DRAININGAT DRUM METAL

TEMP<120 STOPPING OF B/GEARHPT T/B TEMP<120 APPROX 129 HRS GEN CASING DEPRESSURISED.SEAL OIL ISOLATED STOP CW PUMPS AT EXHAUSTHOOD TEMP<60

Frequency

UI Rate (+)

UI Rate (-)

Variable Charges

49.0

406

1000

130.168

49.1

406

910

130.168

49.2

406

820

130.168

49.3

406

730

130.168

49.4

406

640

130.168

49.5

406

550

130.168

49.6

406

460

130.168

49.66

406

406

130.168

49.7

370

370

130.168

49.8

280

280

130.168

49.9

240

240

130.168

50.0

200

200

130.168

50.1

160

160

130.168

50.2

120

120

130.168

50.3

80

80

130.168

50.4

40

40

130.168

50.5

0

0

130.168