Permit to work systemDifferent types of Maintenance of Power Plant and its cost effectiveness

Maintenance PlanningPower Plant Operation

Permit to Work SystemPTW is a printed form and issued to

employee before they may work on specified equipment.

Objective is to ensure safety of employeePTW is Guarantee of Safety

Steps/ Arrangement while issuingPTWPTW 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 issuingPTW …….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 issuingPTW …….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 WorkMaintenance 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 equipmentSafety of PersonsGeneration of Electricity at economic costKeeping generation within the declared

scheduleStart 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 MakingCost Effectiveness in Present Scenario (ABT

- UI)

Grid Discipline Grid Discipline is given a priority in ABTIncentive and penalty in form of UI to

maintain Grid FrequencyPenalty when actual generation is less

than scheduledIncentive when actual generation is

more than scheduled generation when frequency is less

It is a new challenge for operation engineer

U I RateEach 0.02 Hz step is equivalent to 8.0

paise/kwh in the range of 49.8-50.5 HzPenalty is 18.0 paise/kwh in the range of 49.0-

49.8 Hz for each 0.02 Hz stepIncentive 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

STEPSPre Start Up/Light Up ChecksStarting AuxiliariesLight UpRolling and SoakingSynchronizationLoadingOff LoadingShut Down

Type of StartCold StartHot Start

AuxiliariesBoiler Auxiliaries

Milling SystemDraft SystemESP

Turbine Auxiliaries PumpsFeed HeatersDearator

Generator AuxiliariesSeal Oil SystemHydrogen Cooling SystemStator 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 etc1.2 SCRAPPER/SLAG CRUSHER IN SERVICE1.3 BIGGER SIZE OIL GUN TIPS

2. BOILER LIGHTUP2.1 START PA FANS : FLUE GAS TEMP>350

2.11 START MILLING SYS AND PC FEEDER

2.2 START SEAL AIR FAN3. 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 DRAINS6. OPERATE BOILER LPDS AT 10 KSC DRUM PRESS.

6.1 START COND VACC PULLING6.2 CHARGE SEALING STEAM ; 150 mm Hg

Take GSC-1 7. CHARGE HP/LP BYPASS/APRDS MS 30 KSC/330

CELSIUS7.1 READY RESPECTIVE BAY FROM S/YARD7.2 UAT BREAKERS SERVICE REMOTE7.3 AC/DC FIELD FLASHING SUPPLIES ON

8. TPL HEATING DRAINS OPEN8.1 STG-I MS-9,10 OR BYPASS ESV 60%

OPEN8.2 STG-II LOCK IV OPEN ESV=60% MS-5,6

OPEN

START UP PROCEDURE FOR STAGE-I AND II UNITS9. STOP TPL HEATING/NORMALISE

LOCKING10. MANNING OF SEAL OIL SYSTEM

10.1 LINEUP FOR FLANGE/STUD HTNG

10.2 OPEN HPC AND IPC CYL DRAINS11. START ROLLING 500 RPM12. ROLLING 1100 RPM13. ROLLING 3000 RPM

13.1 STOP SOP13.2 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 PRDS15.1 RAISE LOAD TO 50 MW : TAKE UATS IN

SERVICE15.2 OPEN AS-30 STG-I15.3 CHARGE LPHS START DRIP PUMP

STG-I15.4 NORMALISE DEAERATOR EXT –

IN ;HTNG –STOP15.5 CLOSE ALL TURBINE SIDE DRAINS15.6 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 MW18. TAKE AS-49/11 ATA IN SERVICE19. CHARGE ESP ZONES20. ISOLATE FLANGE/STUD

HEATING/STARTING EJECTOR

PLANNED SHUTDOWN OF STAGE-1 UNITS1. REDUCE THE LOAD ALONGWITH OIL

GUNS TO 30-35 MW2. ISOLATE LPHs FROM STEAM AND WATER

SIDE 3. STOP DRIP PUMP4. UAT CHANGEOVER /MAINTAIN PC LEVEL5. TRIP THE UNIT AROUND 20 MW/MS

TEMP=480-450.6. START SOP .LATER ON C/O TO AC LOP

AND AC SEAL OIL PUMP7. CLOSE AS-30 SPINDLE LEAKOFF TO D/A

PLANNED SHUTDOWN OF STAGE-1 UNITS8. PUT TG SET ON B/GEAR. CLOSE SYPHON

FILLING V/V9. KILL THE COND VACUUM.CLOSE AS-9

AND D/A DOME HEATING V/V

10. BOILER LPD OPERATION AT 10 KSC DRUM PRESS

11. RACK OUT UAT BRKR ,OPEN BAY ISOLATOR

12. SWITCH OFF AC/DC FIELD FLASHING SUPPLIES

PLANNED SHUTDOWN OF STAGE-1 UNITS

13. TAKE LOCAL TG SET ECC. START TSI LOGGING

14. SWITCH OFF EP ZONES15. CLOSE FO-116. ISOLATE 11ATA V/V AND OPEN DRAINS17. 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 UNITSPRECAUTIONS:BOILER DRAININGAT DRUM METAL

TEMP<120STOPPING OF B/GEARHPT T/B

TEMP<120 APPROX 129 HRSGEN CASING DEPRESSURISED.SEAL OIL

ISOLATEDSTOP CW PUMPS AT EXHAUSTHOOD

TEMP<60

FrequencyFrequency UI Rate (+)UI Rate (+) UI Rate (-)UI Rate (-) Variable ChargesVariable Charges

49.049.0 406406 10001000 130.168130.168

49.149.1 406406 910910 130.168130.168

49.249.2 406406 820820 130.168130.168

49.349.3 406406 730730 130.168130.168

49.449.4 406406 640640 130.168130.168

49.549.5 406406 550550 130.168130.168

49.649.6 406406 460460 130.168130.168

49.6649.66 406406 406406 130.168130.168

49.749.7 370370 370370 130.168130.168

49.849.8 280280 280280 130.168130.168

49.949.9 240240 240240 130.168130.168

50.050.0 200200 200200 130.168130.168

50.150.1 160160 160160 130.168130.168

50.250.2 120120 120120 130.168130.168

50.350.3 8080 8080 130.168130.168

50.450.4 4040 4040 130.168130.168

50.550.5 00 00 130.168130.168