MOT Centrifuge : Operation

MOT Centrifuge

1. Drain the anti flood tank and close the drain valve after draining.

2. Ensure water level in heater is adequate

3. Check that level in gear box is normal.

4. Ensure make-up water for the heater tank and seal water is available.

5. Ensure MOT oil level is > minimum

6. Line up oil from MOT (clean oil section or dirty oil section) to centrifuge suction.

7. Ensure the manual valve in air locking unit (adjacent to MOT) is open.

8. Open the manual valve in return line from centrifuge to MOT

Operation

1. start the Centrifuge

2. Put all Heater in auto

3. Open seal water line when Centrifuge speed is stable: for 2.5 minutes to make seal

4. after sealing is achieved, close sealing valce

5. Open suction valve of centrifuge

6. Check centrifuge oil outlet pr>1 ksc to 1.5 ksc, if not throttle outlet valve to maniatain it

HP & LP Bypass Operation and Protection

HP & LP Bypass Operation and Protection

Purpose

• Boiler operation independent of the turbine
• Minimum steam flow through SH & RH tubes during start-ups, low load operation & sudden unloading of unit
• Utilized or building up of steam parameters
• Avoiding the boiler trip on Reheat protection
• No steam flow through Boiler steam tubes will lead to starvation & thereby overheating and lead to premature failure of tubes 
• The capacity of HPLP bypass is 60% of full load turbine steam flow 

Reheat Protection:

RH protection (delay=10 sec) will act if

1. TURBINE HP V/V & HPBP CLOSED [ either turbine HP stop v/v or HP CV in both HP line closed ] & [ both HP BP <2%]             OR
2. TURBINE IP V/V & LP BP closed [ Either IP stop v/v or IP CV v/v in both IP line closed ] & [ Either LP BP stop v/v or LP BP C/V in both LP line is closed] OR  
3. Generator ckt bkr open & [both HP BP closed OR both LP BP closed

HPBP Oil Supply Unit Interlocks:

• Pump Auto off Oil Press high >160ksc
• Pump Auto on Oil Press Low <120ksc
• Pump Auto off Oil Temp high >70 DegC
• Pump Auto off Oil Level low <18 Lit
• Alarm Oil Press too high >170ksc
• Alarm Oil Press too Low <90ksc

Pressure Mode:

Stg-2 Mode of Operation 

• Initial Pressure Mode  -
  Importance to the load 
• Fixed Pressure Mode -
  Importance to the Health of turbine.

HP BP Protection:

BP Valve Priority Close Conditions:

• Condenser Vacuum Low (<-0.6 ksc)
• Bypass Downstream Temp very high (>380 degC) 

                    Under these conditions 

• Steam Press Controller Switches to Manual from Auto 
• spray water valve will close
• This protection will override the Fast opening signal & open push button operation

HP Bypass Fast Opening Conditions 

• Generator Circuit Breaker Opening & Boiler on & no priority close
• Turbine Trip & Boiler on & no priority close
• Turbine Load Shedding Relay Operation
• HP BP Pressure Controller Deviation > 8 ksc
• Pressing the Fast Opening Button

BP Valve Auto Blocking Conditions  

• Bypass valve priority close command
• BP position transmitter failed 
• OSU-1 &  2 Oil Pressure <90 ksc
• Main steam Pressure transmitter failed

HP BP Interlocks:

BPE Valve Conditions  

• Steam Bypass Valves BP1 or BP2<2 % Auto Close Command to ensure positive shut off
• Steam Bypass Valves BP1 or BP2<2 % Spray Water Pressure Control Valve (BD Valve) close
• Steam Bypass Valves BP1 or BP2>2 % Spray Water System (BPE1, BPE2, BD Valve) will switch over to Auto

BPE Valve Auto Blocking Conditions  

• Bypass Downstream Temp very high (>380 degC)
• BP auto command blocking
• BPE valve position transmitter failed 
• BPE Temp transmitter deviation high 
• Therefore, it is necessary to make proper set values for Spray Water Header Pressure & HP BP downstream temperature before operating the Steam Bypass Valves

LP Bypass:

Functions of LP Bypass System are:

• Maintaining minimum Steam Flow through Re-heater
• Maintaining desired Steam Pressure in the Re-heater
• Providing an alternative path for dumping the steam (not accepted by the IP & LP Turbines) into the condenser

LP BP System comprises of : 

• Steam Pressure Control Loop
• Valve Position Control Loop
• Automatic Control Interface (ACI)
• Condenser Temperature Protection
• Tracking Unit

LPBP Protections:

Close LP Bypass under following conditions:

1. Condenser Vacuum Low (<-0.6 ksc)
2. Spray Water Pressure Low (<8 ksc)
3. Condenser Wall Temperature High ( > 90 DegC)
4. LPBP Down Steam Pressure High (>19 ksc)
5. Spray Water valve open command at Steam pressure before bypass valve >6.8 ksc 

Boiler Start-Up After BTL

Boiler Start-Up After BTL

• Boiler is out for 1-2 days due to BTL. HP Casing Temp in b/w 300-400 Deg
• One HFO i/s. HFO charged with >110 Deg upto Boiler Front
• Start ID and FD fan. Purge Boiler (5 min cycle)
• Check SH/RH vents Open. APH Soot Blowing lined up.Charge Oil Carry over Probe.
• Turbine on Barring. Start AB all 4 guns(Atom Steam Pr in b/w 6-7 ksc)
• Take Another gun CD(all 4). HFO Prssure~8-10 ksc. Drum Metal Temp Rise~2 Deg/min
• APH Soot Blowing(10-12 ksc Pr) to be done non-stop.
• Drum  Pr~2 ksc. Close SH/RH Vents. Open HPBP Warm-Up valves. Open BSV bypass valves.
• Drum Pr~5 ksc. Open BSVs. Open HPBP~10%. Close HPBP Warm up Valves. 
• Close SH/RH Header drains at ~ 14 ksc(Drum Pr). Put HPBP spray on Auto.
• FG path of PA fan through. Start one PA Fan and one Seal Air Fan
• MS Pr~80 ksc & MS Temp~365 Deg. HRH Pr~12 ksc & HRH Temp~325 Deg. Maintain using HPBP and LPBP valves.
• Float A mill(charge air). Cut in A mill ~ min flow 17 TPH.
• No SH/RH spray till now. Secondary Air Temp~175 Deg. 1st Mill Before synchronization.
• Reduce firing accordingly to control Temp Rise
• Turbine Running ~ 3000 rpm. Synchronise Machine. Take ~50 MW Block Load. 
• Ensure Closing of HPBP and LPBP valves with spray on Auto. Increase HPBP set point. 
• Float 2nd Mill(B). Charge all ESP Fields. Increase Mill-A firing.
• Firing to maintained ~1.5 T/min upto 250 MW to limit any abrupt Temp Rise for that spray is required.
• Load~60 MW. MS~60 ksc. Load Controller in action. Charge LPH-2 & 3 with Level controller in Auto. 
• Charge Deaerator Pegging by CRH Ext. Cut in all Auto controllers. Cut in 2nd Mill.
• Load ~110 MW. MS~80 ksc. Charge PRDS from CRH. Cut HP Heaters and Level controller in auto. Cut in 3rd Mill.
• Load~150 MW. MS (100 ksc/435 Deg). Start 2nd PA fan(FG & Air Path available)
• Control MS & RH Temp by spray if Required. Cut in 4th Mill. Check Scanners,'
• Load~250 MW. MS~125 ksc/450 Deg.  Cut in 5th Mill. Roll 1st TDBFP & Put on Load.
• Cut-off Oil Support Completely. Cut in 6th Mill if required. 
• Change MDBFP with TDBFPs. And stop MDBFP.
• Load~350MW. MS~140ksc/480 Deg. Increase Set point of SH/RH Spray to achieve rated SH and RH Temp
• Load~500 MW and Scan all Parameters/ Loops/ Controllers.

Safe Shut Down Procedure-StageII 500 MW Rihand

1	MDBFP – Available & Standby
2	Oil gun: HFO Pr/Temp=16 ksc/>110 Deg , Atom Steam: 6.5ksc/>220 Deg (Open steam drains @AB elevation)
3	Turbine on LP mode, Boiler Master in Manual(Manual Mode)
4	Isolate PRDS from CRH for this unit, Increase the set point to other units @ 13.5 ksc/ Temperature >280 deg
5	Open GS supply line drain to atmosphere
6	Charge APH soot blowing line from PRDS
7	Load-500 MW with 6 Mills(Roughly @ 55 tph each)
8	Cut feeding in top mill & Stop mill, other 5 mills >=40 tph/ load ~325 MW,In b/w reduce ThrotPr- 170 to 150 ksc
9	Take AB & CD elevation gun/ Start APH Soot blowing
10	Start MDBFP in Manual(cold) & Load/ unload anyone TDBFP(<=3500 rpm), MDBFP-auto & FW master-Auto
11	Switch off ESP fields as guns been taken & proved
12	Cut feeding in Bottom Mill & stop it/ Now 4 mills/ Ms Pr ~130 ksc/ load <=300 MW (Reduce feed in top mill too)
13
14	Load~225 MW with 3 Mills+ 2 elev oil guns/ Unload TDBFP, keep load on MDBFP(Off CRH block v/v of TDBFP)
15	Trip the other TDBFP/ Reduce feed in bottom mill/Load~175 MW/ Unload one PA fan/ Reduce MsPr~90-100 ksc
16	Changeover UT to ST / Trip 2nd TDBFP
17	Trip bottom mill/ Load 140 MW/ 2 Mills +AB1324 CD13 or CD24 guns / only MDBFP in service
18	Bring load ~80 MW by cutting upper mill & opening HPBP further
19	Maintain drum at least +50mm to +100mm before hand tripping turbine(to avoid boiler trip on drum level Lo-Lo)
20	Hand Trip Turbine/ Turbine tripped (1 mill +6 guns i/s + MDBFP i/s)
21	Maintain TG lube oil temp>50 deg/MAL drain open/AOP starts @2850rpm/close all S/ RH spray v/vs
22	Stop mill, Stop guns/ boiler will Trip on Loss of all fuel/ All PA, HOTV/LOTV
23	Depressurise boiler to 45-50 ksc before closing boiler stop valve thru HP/LP bypass
24	Close Boiler stop valve/ De pressurise MS/HRH line thru HP/Lp BP/ after that close HPLP bypass/ Close manual of HPBP spray v/v
25	Purge boiler for 10 min(2 cycles)
26	Stop one set of ID and Fd fans after purging
27	cool boiler furnace Pr(= -10 to -20 mm)/ Monitor rate of ccoling by following BCW suction manifold temp<87 deg/hr
28	Drum level to be maintained as such till drum metal temp reaches 100 deg

PA Fan : Stg-II : Operation & Important

PA Fan : Stg-II : Operation & Important

Important Information :

• Capacity: 700 TPH
• Total Head Devleoped: 1200 mm WC
• Speed: 1480 rpm
• Rating: 2.775 MW and 11 KV
• Full Load current: 169 Amp
• Overload alarm: 180 Amp (TD 20 sec)
• Overload Trip: 192 Amp
• Normal Header Pressure: 820 mm WC
• Current: 90 Amp
• Blade-Pitch: 60 %
• Blade Pitch Locking: 85 %
• Trip : Low =650 mmWC(TD-5 sec) | Low-Low=550 mmWC(Instant)

Prestart checks & Loading:

• Check air path is available .  At least one PAPH is ON and air path of the APH available (APH air I/L & O/L dampers are open), for second PA fan both PAPH must be on 
• Remote / local selector switch of blade pitch mounted on the actuator is selected in remote and the blade pitch is in minimum position. 
• Check that the outlet (discharge) damper is in closed position and in remote 
• Check the PA fan discharge duct drain valve is in closed position .After shut down with
  air preheater water washing this duct drain should be opened first to check any water
  accumulation inside fan casing, before taking PA fan into service.
• Keep cold air gate damper of at least two mills open so that minimum air flow is assured 
•  Start the fan with blade pitch minimum position and ensure opening of discharge damper fully. Then gradually increase the blade pitch position to load the fan.  

STARING OF SECOND PA FAN:-  

• Both PAPH must be ON and its inlet and outlet damper open 
• At least three mills be in service 
• Put blade pitch of 1st PA fan in CAS and PA header pr. In auto with set point 850 mmwcl – 900mmwcl. 
• Start 2nd PA fan and put blade pitch of 2nd PA fan a command of 10-15% as the discharge damper starts opening and close feed back disappears. 

Trip:   

• PA Header Pr Low =650 mmWC(TD-5 sec) | Low-Low=550 mmWC(Instant)
• Vibration: 20 mm/sec for 120 sec OR 28 mm/sec for 5 sec

PTW Preparing steps

PTW Preparing steps

• Use T-code WCLE
• Enter Planning Plant-1005
• Set filter- Operational WCDs
• Select Prepared  WCDs
• Enter- Valide From and TO Date
• Select " Reference Object" tab
• Type " cr2" in train blank place
• click " Execute" button (clock button)
• Select  PTWs to be prepared(Using Checks)
• Click " Hierarchy" Button
• Click "Switching Screen" (gear shape)
• Click " Select all Button"
• Click " tag" button
• Click " continue" button
• Click " Edit/ Print/ Operational List/ tagging List
• Click "Print Preview" button
• Click back button
• Click " tagged" button
• Click back button
• Click " Operational WCD/ function/Print
• Check Information below.

PTW Closing steps

PTW Closing steps

• Use T-code WCLE
• Enter Planning Plant-1005
• Set filter- Operational WCDs
• Select CLOSED (green) WCDs
• Enter- Valide From and TO Date
• Select " Reference Object" tab
• Type " cr2" in train blank place
• click " Execute" button (clock button)
• Select  PTWs to be closed(Using Checks)
• Click " Hierarchy" Button
• Click "Switching Screen" (gear shape)
• Click " Select all Button"
• Click " Untag" button
• Click " continue" button
• Click " Edit/ Print/ Operational List/ Untagging List
• Click "Print Preview" button
• Click back button
• Click " Untagged" button
• Click back button
• Click " Operational WCD/ function/Close
• Check Information below.

Boiler Hydro Checklist

Equipment availability:

• CW duct charged
• ACW pump available,ACW strainer boxed up
• ECW pump available
• ECW tank filled.
• DM/CST pump available.
• Boiler fill pump available.
• Wet Lay up pump, NH3, N2H4 pump available.
• Condenser Hotwell normal level.
• CEP available, DA level C/V, Isol. Valve operation OK
• CPU one stream available.
• Deaerator boxed up, level normal.
• MD BFP’C’ available, lined up.
• Feed line vented upto FRS.
• FRS LOW range C/V, Isol. Valve opn OK OK
• LPH, HPHs bypass valve available & lined up.
• Eco inlet valve E2 open (Operation) OK
• Eco R/C valve E18, E20 Opn OK.
• Boiler drum clearance.
• Low point drains header valve clearance.
• SH header valves clearance.
• SH spray valve clearance & all valve closed.
• All CC pumps cavity filled.
• Boiler stop valve (L&R) opn checked, Integral bypass opn OK
• EBD, CBD, IBD valve cleared, opn checked.
• SH drain valve before Blr. Stop valve opn OK.
• SH air/startup vents opn OK.
• Drum vents Opn OK.
• Soot blowing steam Isol. (Manual) valve closed.
• RH spray main block valve close.
• Main steam strainer drain & MS line drain open.
• CRH line drain open.
• HP bypass spray line manual valve close.

SAFETY PRECAUTIONS:

• Lighting on all boiler elevations are available.
• All scrap materials/Insulation materials removed & areas cleaned.
• All permits on required equipment/valve cleared & clearance given.
• The fire water pump is running.
• The healthiness of all supports & hangers are checked.
• Hydrostatic test plugs/gags were fitted on all the boiler safety valve.

Following systems Readiness/Trial was taken:

• DM Tank/CST tank flushed, water quality ensured.
• DM plant informed for Hyd. Test.
• Hotwell flushing done on______ & filled to normal level.
• ECW tank flushing done on______& filled upto normal level.
• D/A flushing done on_______& filled upto high level.
• D/A level, level switches alarm OK.
• CW ducts are charged by opening ICV on__________
• ACW trial taken on_________ kept I/s.
• DMCW pump trial taken on_________kept I/s.
• CEP Protection/Interlock checked, Trial taken on_________.
• MD BFP’C’ protection & interlocks checked & trial taken on________
• Boiler drum level Tx, hydrastep, PG/ pr.Tr for drum & MS line before ESV charged & made available.
• CC pump filling completed on  

Drum Filling Procedure

• Blr. Filling clearance from O/H group on -----.
• Blr. Stop valve, Int. bypass valve fully closed.
• Startup vents, SH vents, Drum vents are fully open.
• SH header drain individual valves open & master drain closed.
• Boiler water sample line is closed.
• Low paint drain header lined up through Bottom ring header.
• CBD, EBD, IBD valve, SH header drain valve before ESV closed.
• FRS low range is lined up, Eco inlet valve open.
• PO4 dosing line valve, SB manual valve closed.
• All SH/RH spray valve closed.
• MS strainer & MS line drain, CRH line drain valve open.
• Boiler fill pump started & kept on R/C.
• NH3, N2H4 dosing soln. ready & lined up for BFP.
• Start wet lay Pump.
• Start filling the Boiler through SH filling line for back flushing.
• MD BFP’C’ is started & in R/C.
• Maintain water quality by running NH3 & N2H4 pump, Wet lay p/p.
• Start taking water through BFP’C’/TDBFP.
• When drum level becomes normal, isolate filling line & stop BFP.
• When water starts coming out through Drum vents SH vents, closed all vents at 2KSC drum pr.
• Close SH start up vents after closing all air vents.
• Drum level high, high high alarm checked.

BOILER PRESSURISATION:

• Boiler is pressurized slowly upto desired pr. (as per requirement of Blr. Inspector or maintenance).
• Drum Pr. high, high high alarm appeared.
• Pr. maintained for 10 mts. at required pr.
• Boiler pr. reduced to 120 KSC.
• Inspection of boiler pr. parts, Drums, CC pumps carried out.
• Leakages observed.
• Rate of pr. drop observed.
• Boiler depressurized & drum/SH vents opened at 2KSC,
• SH,W/W,Economizer drained.
• Drum level low/low low alarm appeared.
• Remark:

BOILER HYDRO TEST CHECKLIST1. WORK IN BOILER STEAM & WATER CIRCUIT COMPLETED.
2. BOILER DRUM BOXED UP.
3. RING HDR MANHOLES BOXED UP.
4. DRUM VENTS,SH VENTS/START UP VENTS AVAILABLE
5. SH DRAIN(18 NO) + MASTER DRAIN BOXED UP.
6. SH FILLING LINE CONNECTION TO SH DRAIN HEADER COMPLETED
7. ALL V/V’S IN LOW POINT DRAIN HDR ALONG WITH MASTER DRAIN
BOXED UP.
8. CBD/EBD/IBD ISOLATING V/V’S AT DRUM LEVEL CLOSE
9. SOOT BLOWER STEAM LINE Ist ISOLATING V/V TOWARDS BOILER
CLOSE
10. PHOSPHATE DOSING ISOLATING V/V CLOSE,
11. CC P/PFILL&PURGE COMPLETED/ANY ONE CC P/P DISCH V/V OPEN
12. BOILER DRUM & SH SAMPLING LINE ISOLATING V/V CLOSED
13. MDBFP AVAILABLE.
14. D/A & FST AVAILABLE FILLED UPTO NORMAL LEVEL.
15. BOILER FILL P/P’S AVAILABLE
16. ALL BFP’S SH & RH SPRAY LINE ISOLATING V/V’S CLOSE.
17. BD V/V’S MANUAL ISOLATING CLOSED
18. MS 1,2,3,4,5&6 CLOSED TIGHTLY & SUPPLY ISOLATED.
19. MS 9 & 10 CLOSED( SUPPLY ISOLATED). THEIR MANUAL ISOLATING
V/V CLOSED.
20. E2 & E2A AVAILABLE –OPEN
21. E20 ( ECO RECIRCULATION )AVAILABLE.
22. ALL TURBINE SIDE (MS/HRH/CRH) LINE ATMOSPHERIC DRAINS FULL
OPEN.
23. MS/HRH STRAINER DRAIN TO IBD TANK OPEN.
24. HP/IP STOP V/V’S GAGGED IN CLOSE POSITION.
25. HYDRASTEP & DRUM PR. TRANSMITTERS AVAILABLE.
26. MS PR. GAUGE( BEFORE STOP STOP V/V’S) AT DRUM LEVEL AVL.
27. HP HEATERS FW CIRCUITS & FRS V/V’S AVAILABLE.
28. MS PRDS MANUAL V/V AT PRDS TIGHTLY CLOSD.
29. ECW/DMCW SYSTEM AVAILABLE WITH ATLEAST ONE DMCW P/P I/S
FOR MDBFP COOLING WATER.
30. ATLEAST ONE CLCW P/P I/S(OPTIONAL)
31. ATLEAST ONE PHE CHARGED FROM DMCW/CLCW SIDE.
32. WETLAY P/P AVAILABLE(LINED UP TO LOW POINT DRAIN HDR.
33. CHEMICAL SOLUTION AT DOSING TANKS( HYDRAZINE/AMMONIA)
AVL.
34. CC P/P CAVITIES FILLED/ FILL PURGE COMPLETED.
35. ERV(MS LINE) MANUAL V/V CLOSED.

500 MW BOILERS

CHECKLIST FOR HYDRO – TEST

UNIT:                                                                                                                                 DATE:
S.N. DESCRIPTION RESP. STATUS REMARKS

01. CC Pumps cavity filled. Opn.
02. MS stop valves & equalisers closed. Opn.
03. MS ERVs isolating valves closed. Opn.
04. Soot blowing station isolated. Opn.
05. CBD root valve closed. Opn.
06. SH attemperation valves from all BFPs Opn.
Closed.
07. RH attemperation valves from all BFPs Opn.
Closed.
08. SH / RH attemperation station cleared. PP
09. HP Bypass spray valves & manual Opn.
Valve closed.
10. PRDS spray, manual valves closed. Opn.
11. Condensate system cleared & charged. TM/Opn.
12. Feed water system cleared & charged. TM/Opn.
13. CEP, MDBFP P&I checks completed, C&I/Opn.
Pumps started & kept in service.
14. HP Bypass valves & main turbine TM/Opn.
Stop valves are closed.
15. MS line drains are kept open. Opn.
S.N. DESCRIPTION RESP. STATUS REMARKS
16. MS and Drum safety valves are gagged PP
(for pressures above 180 KSC).
17. Necessary C&I indicators and recorders C&I
are available.
18. Men & material removed from Boiler PP
first and second pass.
19. Men & material removed from bottom AHM
ash hopper and economiser hoppers.
20. Clearance for boiler filling obtained, PP
from Pressure Parts.CLEARANCESS.N. DEPARTMENT SIGNATURE REMARKS
01. Pressure Parts (PP)
02. Turbine Maintenance (TM)
03. C&I Maintenance (C&I)
04. Ash Handling Maint. (AHM)
05. Opn. / Recommissioning
HYDRO-TEST DETAILSINTERNAL:Date / Time :
Pressure (KSC) :
Leakages, if any :
Result :EXTERNAL:Date / Time :
Pressure (KSC) :
Leakages, if any :
Result :Signatures:Pressure Parts Opn./ Recommissioning

220V DC FAILURE

220V DC FAILURE

IDENTIFICATION:

• Boiler and Turbine will trip.
• 220V DC failure alarm will appear in facia & DCDB voltage will read 0V
• Generator will start motoring & motoring alarm will appear.

CONSEQUENCES:

•  Boiler will trip on “220V DC failure” protection by FSSS.

1. HOTV & LOTV will close.
2. All running mills CAD’S & HAG’S will close.
3. All running mills feeders will trip.
4. SADC will full open.
5. All HT (11kv & 3.3kv) drives will continue to run.
6. All mills, PA fans, CC pumps, ID&FD fans will continue to run.

• Turbine will trip on boiler trip protection through MFT.

1. all stop valves & control valves will close.
2. TDBFP A&B will trip.
3. MDBFP if not in service will not take start.
4. Extraction FC NRV will close.
5. Vacuum breaker remains close.

• Generator will start motoring & will not trip (All electrical protection will not work)
• Field breaker inoperative.
• All HT breakers protection is not available.
• All DC oil pumps & scanner air fan are not available.
• Generator breaker DC is from SY hence Breaker is operable from UCB but “DO NOT OPEN GEN BREAKER”. This will cause:

1. BA,BB & CA bus dead as UT to station change over will not takes place.
2. All critical equipments AOPS, JOP, Seal oil pump, AC scanner air fan Power supply will not be available.

ACTIONS:

1. Start DG set from UCB.(DG set control supply (DC) is not available)
2. Rush to local, trip emergency SWGR normal incomer breaker & close tie from DG set
3. Trip UT incomer breaker from local.
4. Start TG AOP#2, TDBFP’sAOP#2, and seal oil pump #2 from UCB.
5. AC scanner air fan will continue to run.
6. Trip generator breaker.
7. Switch off De-excitation switch at AVR panel.
8. Switch off field breaker from AVR panel.
9. Start jop#1 at TG speed of 510 RPM.
10. Restore DC as quick as possible.  

Post Shutdown Instructions for UCE

POST SHUTDOWN IMMEDIATE UCB OPN 

1. Check & ensure GCB IS open.
2. Check & ensure Starting of AOP of main turbine after 2850 RPM.
3. Ensure HPT evacuation valve opens after turbine tripped provided condenser vacuum is better than -
0.4ksc and closes at 2000 rpm.
4. Put FRS low level controller in service and maintain drum level. In case of difficulty in maintaining drum
level or at low CC pump DPs, CC pumps may be tripped .
5. Maintain Furnace Pressure & Put Master in auto.
6. Check & ensure All ESVs, & IVs and HPCVs & IPCVs get closed.
7. Maintain Seal Steam Pressure for maintaining Vacuum. Close Leak-off bypass if open. Keep watch on seal
steam temperature.
8. Raise turbine oil temperature set point to 60 oC during turbine coasting down & maintain temp. If
needed, isolate MOT cooler.
9. Check & ensure CRH NRV and All Extraction V/Vs get closed.
10. Maintain Hot well & D/A levels.
11. Check & ensure Starting of JOP (510RPM) and Barring gear opening (210RPM). DC-JOP starts if JOP 1
discharge pr is < 110 ksc. Ch/over to AC JOP and ensure SLC is ON.
12. Charge MS PRDS from other unit & maintain seal steam I/L temp in 280 oC to 320 oC.
13. Check & ensure Closing of PAPH-A,B FG outlet control dampers.
14. Check & ensure HOTV,LOTV and All HONVs, LONVs get closed. Mill & feeders trip.
15. Instruct for closing HPBP/SH/RH Spray manual isolating valves, RECORD COMPLIANCE. ENSURE CRH
DRAIN POT DRAIN: CRHV-101 & DRAIN BEFORE CRH-NRV: MAL-65 manual valves are kept OPEN.
16. Reduce D/A Pressure by closing control v/v from PRDS gradually with Maintaining PRDS pressure.
17. Switch-off ESP fields.
18. Reduce OAC make-up flow at appropriate level.
19. Isolate fuel oil station from firing floor.  

Main Turbine Oil Injection Procedure

Main Turbine Oil Injection Procedure

• Communicate to senior persons such as AGM(O) & AGM(MM) regarding the test plan.
• Ensure the presence of TMD person near Governing rack at 17 Mtr.
• Rotate the knob of Governing rack filter (daily once in Evening shift)  
• Open the Top cover of pilot valves KA02 and KA03 of MAX62AA001.
• Press the pilot valve KA02 fully and observe the Aux. start-up fluid pressure is developing or not. lf pressure is ok , slowly release the valve. If the pressure does not build-up, abort the test. Release the valve after checking.Inform to TMD.
• Press the pilot valve KA03 fully to isolate the Auxiliary trip fluid (going to over speed bolts through over speed trip test device) from main trip valve and keep in pressed down till the completion of the test. Note down the Auxiliary trip fluid pressure
• Rotate the hand wheel KA01 of over-speed trip test device in clockwise direction for
  admitting the test fluid to the over speed Bolts.  
• The actuation of over speed bolt is indicated on the test rack by lamps for limitswitches MAY10CG001 and MAY10CG002, provided on the LHS of front bearing
  pedestal.
• Check whether Auxiliary trip fluid pressure goes to zero.
• Note down the test oil pressure / Turbine sped / Primary oil pressure , when overspeed striker bolts 1 & 2 acted and ensure alarm in UCB / SOE/ Local Governing Rack panel.
• Confirm physically that both over speed bolts have operated.
• Rotate the hand wheel KA01 of over-speed test unit in the anticlockwise direction where the test fluid gets cut off to the over speed bolts.
• Ensure test oil pressure showing zero value.
• Press the Pilot valve KA02 of over-speed test device to reset over speed bolts 1 and 2.Check whether Auxiliary trip fluid pressure builds up and it is as per the recorded value. Slowly release Pilot valve KA02 of over speed test device. Aux start up fluid Pressure become to zero.
• Repeat previous step to ensure resetting of over-speed trip device bolts.
• Confirm physically that both over speed bolts have resetted & also take confirmation from TMD also.
• Wait for some time & allow auxiliary trip fluid pressure to be steady at around 5 Kg/cm2. Slowly release the knob of pilot valve KA03, of over-speed test device & observe rise in AUX TRIP FLUID PRESSURE.
• Press the pilot valve KA03 fully, of over-speed test device if any drop in Auxiliary trip oil pressure or Load during the releasing of pilot valve KA03.  

TDBFP Oil Injection Test Procedure

TDBFP Oil Injection Test Procedure

• Communicate to senior persons such as AGM (O) & AGM (TMD) regarding the test plan.
• Ensure the presence of TMD person near TDBFP Governing rack at 17 Mtr.
• Ensure that MDBFP is in auto and its start permissive is available.
• TDBFP speed should be greater than 5300 rpm and it may be increased through biasing. During biasing care has to be taken that other TDBFP may not get unloaded.

• First of all Press the Test Valve lever and lock it by rotating hand wheel in clockwise direction. It will isolate the trip fluid (going to over speed bolts through the test valve) from main tripping device and keep in pressed condition till the completion of the test  
• Open the manual isolating valve of test oil line. Now slowly increase the test oil
  pressure through test oil regulating valve.
• When test oil pressure increases above 2.5 ksc, increase it slowly further and note
  down the test oil pressure at which Fly bolts operate. The downward movement of Its
  lever, confirms the actuation of tripping device.  
• Reduce test oil pressure by closing test oil regulating valve.
• Close the manual isolating valve of test oil line.
• Now unlock the test valve by rotating the hand wheel in anti-clockwise direction and
  slowly release it. First start up oil pressure will build up & it will reset the trip device.
  After resetting, release the test valve completely & observe trip oil pressure.  

PAPH OIL SYSTEM

BCW Pump scheme

VAM

Protection Rack

Governing Rack

ESV & HPCV CF Scheme

LPBP Rack

Legend of Governing system

Heat Balance 500 MW

Overspeed : Oil Injection & Actual

PROCEDURE FOR PERFORMING OVERSPEED TRIP OIL INJECTION TEST FROM LOCATION:

STEP-1: Press the RHS knob and ensure build up of startup oil pressure (>8.5 ksc), Note down and release the lever.

STEP-2: Press the LHS Knob and hold it in the pressed condition till completion of test. Not down Aux trip fluid pressure (>5.0 ksc).

STEP-3: Rotate the testing device hand wheel in clock wise direction to build test oil pressure.

STEP-4: Note down the test oil pressure at which the Over speed trip device strikers act, Aux trip fluid pressure (0 ksc) and primary oil pressure.

STEP-5: Rotate the testing device hand wheel in anti clock wise direction to reduce test oil pressure till 0 ksc.

STEP-6: Press the RHS knob to buildup startup oil pressure and reset the trip device and then release it after ensure resetting of both strikers.

STEP-7: Release the LHS knob and note down Aux. trip fluid pressure (>8.5 ksc). Resp: UCE

PROCEDURE FOR ACTUAL OVERSPEED TEST-MAIN TURBINE

6.1: PRECAUTIONS

6.1.1 The persons carrying out the test must be aware of the maximum speed at which the prime mover may be run and the need to limit over speeding to the minimum duration.

6.1.2 Before carrying out an over speed test on a turbine generator, precautions must be taken to ensure that the field breaker is open and the machine is in de-excited condition. Resp: UCE

6.1.3 Check that the healthiness of the overspeed trip device has been ensured earlier by performing oil injection test within a period of 30 days. Resp: UCE

6.1.4 Ensure that oil injection test (onload testing equipment) was not carried out immediately before the actual overspeed test to avoid freeing of the gear giving an artificial result. Resp: UCE

6.1.5 Before carrying out any overspeed test, precautions must be taken to limit the supply of steam or fuel to the minimum necessary machine should be warmed up sufficiently so that casing expansion are at least 80% of full load expansion. Expansion readings are taken and logged. Resp: UCE

6.1.6 During an overspeed test, two independent speed indicators are desirable and both must be watched for any sign of malfunction. Resp: C&I

6.1.7 The turbine desk should be manned and the turbine should be hand tripped above 3330 RPM. Resp: UCE

6.1.8 The manual emergency trip must be manned by a person who can see clearly the speed achieved and who will trip the prime mover if the maximum permissible speed is exceeded or it the prime mover shows signs of distress. This person must be in direct communication with the person controlling the speed of the prime mover. Resp: UCE

6.2: PROCEDURE FOR DOING ACTUAL OVERSPEED TEST DURING SHUTDOWN:

6.2.1: During load reduction take the turbine control to hydraulic by reducing speeder gear at about 50MW in Stage-I and 150 MW in Stage-II and close the EHC isolation valves. (Applicable to stage-I only: Changeover 6.6 KV Unit bus supply to Station Supply). Resp: UCE

6.2.2: Reduce boiler firing and load gradually. Resp: UCE

6.2.3: Charge HP/LP bypass and reduce throttle pressure to 50 ksc, while avoiding steep drop in temperature. Resp: UCE

6.2.4: Reduce load further after bringing the boiler load to minimum with 02 consecutive mills in service preferably C & D with 01 elevation of oil guns. Resp: UCE

6.2.5: Reduce the load to zero MW and then desynchronize the machine, open field breaker. Resp: UCE

6.2.6: Cross check the speed measurement with an offline digital instrument. Resp: MTP

6.2.7: Increase electrical over speed protection set point to 3330 rpm. Resp: C&I

6.2.8: Bring turbine speed to 3000 RPM by operating speeder gear / Starting device. Further raise the speed and ensure maximum speed reached with both Starting device and Speeder gear at 100% is around 3210 rpm. Resp: UCE

6.2.9: After ensuring that all the precautions are met, raise the turbine speed from local by rotating the over speeding knob. Resp: UCE

6.2.10: Note the speed at which the turbine trips, along with the corresponding primary oil pressure and record it. Resp: UCE

6.2.11: Normalise Electrical overspeed setpoint. Resp: UCE/C&I

NOTE: The maximum permissible speed at which the test is to be carried out should be decided before doing the test, and informed to all persons involved in the test.

6.3: PROCEDURE FOR DOING ACTUAL OVERSPEED TEST DURING STARTUP AFTER OVERHAUL:

6.3.1 Before the turbine is rolled, its Stop valves operation, Governing characteristics, CRH NRV operation and Extraction lines FCNRVs operation must be checked for smooth operation over the maximum travel practicable in such circumstances. Resp: Re-commissioning Incharge / TMD

6.3.2 Before the turbine is rolled its governor should be set to commence controlling the speed at the lowest speed possible. Operation of the governor, control gear and all valves must be observed for signs of sticking or other malfunction. Resp: Re-commissioning Incharge / C&I / TMD

6.3.3: Before rolling the turbine Turbine tripping (Closure of Stop valves) must be ensured through Remote HMI trip, Local Governing rack trip lever and also through electrical over speed protection by simulation as part of Protection & Interlock checking, Protocol must be signed. Resp: Re-commissioning Incharge

6.3.4: When the turbine generator is being returned to service, the steam tightness of the Steam Control Valves must be proved by ensuring the turbine does not accelerate from the barring gear speed when the Turbine stop valves are opened and control valves are in closed condition. Resp: Re-commissioning Incharge /TMD

6.3.5: During first run-up after overhaul, Shaft speed should be measured with a digital Tachometer and speed indicator readings compared with Tachometer reading. Resp: Re-commissioning Incharge / MTP

6.3.6: After the turbine has been rolled to 3000 rpm, perform oil injection test (preferably before electrical testing of generator) and ensure both strikers act, record Primary oil pressure and Test oil pressure at which the strikers act. Resp: Re-commissioning Incharge Resp: Re-commissioning Incharge

6.3.7: Allow the overall expansion to reach 80% of full load expansion. During the course of electrical testing, the steam temperatures may be increased gradually to achieve the expansions. Resp: Re-commissioning Incharge

6.3.8: Cross check the speed measurement with an offline digital instrument. Resp: MTP

6.3.9: Increase electrical over speed protection set point to 3330 rpm. Resp: Re-commissioning Incharge / C&I

6.3.10: Bring turbine speed to 3000 RPM by operating speeder gear / Starting device. Further raise the speed and ensure maximum speed reached with both Starting device and Speeder gear at 100% is around 3210 rpm. Resp: Re-commissioning Incharge / TMD

6.3.11: After ensuring that all the precautions are met, raise the turbine speed from local by rotating the over speeding knob. Resp: Re-commissioning Incharge / TMD

6.3.12: Note the speed at which the turbine trips, along with the corresponding primary oil pressure and record it. Resp: Re-commissioning Incharge

NOTE: The maximum permissible speed at which the test is to be carried out should be decided before doing the test, and informed to all persons involved in the test.

7.0: PROCEDURE FOR ACTUAL OVERSPEED TEST OF TDBFP DRIVE TURBINE

7.1 Oil injection test to be done before stopping TDBFP as per the procedure given below:

Step-1: Open control oil supply v/v to test oil generating device.

Step-2: Push & hold lever of over speed test device downwards completely. This will ensure stop v/v in open condition.

Step-3: Holding lever downward, rotate hand wheel slowly in clockwise direction to generate/increase test oil. Note test oil pressure at which over speed protection device operates.

Step-4: Rotate hand wheel anticlockwise completely to reduce test oil pressure.

Step-5: Energise Remote trip engage to reset the device. Release the lever and De-energise Remote trip engage after device resets.

Step-6: Close control oil supply v/v to test oil generating device.

7.2 Record test oil & speed in protect check register. If oil injection test is not satisfactory, reason is to be investigated. If speed cannot be raised to 5400 rpm (approximately) due to low load conditions, then at least try to ensure buildup of test oil pressure. Resp: UCE/ TMD

Preparation for Overspeed test:

7.3 TDBFP is to be stopped as per shutdown procedure & kept on barring. TDBFP to be isolated from steam side. Both vacuum p/p can be taken in service if required. Resp: UCE

7.4 When turbine casing temperature reaches less than 120 degree, stop barring of TDBFP .TDBFP is to be isolated from oil side and permit to be issued for decoupling of turbine from main pump & gearbox (BP) side. Resp: UCE /TMD

7.5 After decoupling of turbine, charge oil system & put TDBFP on barring. Adjust turning gear valve to maintain barring speed 500 rpm (approx). Resp: UCE /TMD

7.6 TDBFP governing characteristic to be checked. Resp: TG desk engr/TMD/C&I

7.7 Ensure closing of control valves before opening ESV. Resp: TG desk engr

Procedure for Overspeed test:

7.8 Ensure tripping of turbine (closure of stop valves) through Local trip gear, Remote HMI trip and electrical overspeed protection (by reducing setpoint below barring speed). Resp: TG desk engr/C&I

7.9 Charge TDBFP from steam side with aux PRDS v/v as per procedure. Charge Extraction source also if available (i.e If Main turbine is in service).Resp: TG desk engr.

7.10 During speed rising, close monitoring is required for control valve opening, if control valve is not opening as per speed control output, trip BFP and investigate reasons. Resp: UCE/TMD

7.11 Roll TDBFP turbine as per the allowed rate and soak at 2000, 4000 and 5400 rpm for 30 min each. Offline speed to be measured by MTP at above speeds. Turbovisory parameters also to be observed. Soak the turbine at this speed till casing temperature reaches 200 deg C. Resp: TG desk engr /MTP

7.12 Carry out Oil Injection test three times to ensure the healthiness of over speed trip device and consistency in test oil pressure at which bolt acts is to be established. Procedure for oil injection test given in 7.1 to be followed. Resp: UCE/MTP/TMD

7.13 Turbine electrical protection set point to be raised 6100 from 6000 rpm & Speed reference blocking to be increased to 6100 rpm from 5800rpm. “OS Test” Push button to be pressed (Turns green) to remove blocking of Nrtd at 5800 rpm. Resp:UCE/ C&I

7.14 Before going for actual over speeding ensure Remote trip engage is in De-energised condition as this will not let the device act. Resp: UCE/C&I

7.15 Turbine speed to be increased in steps of 100rpm till 5900 rpm & later in step of 50 rpm. Operation executive/TMD executive should be present in local to trip TDBFP if speed goes beyond 6100 rpm. MTP engineer should be present in local to measure speed offline. Turbovisory parameters to be kept under observation. Resp: HOD operation /HOD TMD /HOD(C&I)MTP

7.16 Note the speed at which turbine trips. Maximum TSI parameter to be noted. Resp: UCE/TMD

7.17 Restore OS protection setpoint to 6000 rpm and Speed reference blocking to 5800 rpm. Press the “OS test” button in mimic (Turns Red) to restore 5800 rpm limit on Nrtd. Resp: UCE/C&I

8.0 FREQUENCY OF ACTUAL OVERSPEED TEST

A Turbine on which on load oil injection test being carried out successfully on monthly basis, shall be given an actual overspeed test at intervals of 24 months or as per manufacturer's recommendation whichever is less.

If the on load overspeed test mechanism by oil injection is not functioning, then the actual overspeed should be carried out while stopping the machine for planned shut down or before taking the machine again in to service

If, for any reason, it is not possible or practicable to carry out an actual overspeed test at least once every 12 month, then this should be reported to the Director of Operation, and formal dispensation sought on each and every occasion.

Boiler Start-up Procedure (Cold)

Boiler Start-up Procedure (Cold)

• Open-Drain Bef MSV, RH & SH Vents, RH & SH Drains, Drum Vents |  Close- MSV 
• Time: 00 ' | Charge AB HFO (all 4 burners) (Oil Pr~8-10 ksc) | Drum Mtm <2 Deg/Min 
• Time: 30 ' | Charge CD HFO (keep in Min 2 Deg/Min Mtm) | Atom. Steam Pr~ 6 ksc
• Charge & Operate APH Soot Blowing (Pr~10-12 ksc) | Keep Open Eco R/c Till 30 % BLI
• Open HPBP Warm-up valves
• Time: 60 ' | Drum Pr~2 ksc | Close SH, RH Vents | Open MSV Bypass Valves |MS. CRH. HRH will get warmed up
• Time: 100 ' | Drum Pr~5 ksc | Open MSVs | Open HPBP Valves 8-10% | Close SH, RH  drain at Drum Pr ~ 14 ksc | Close HPBP warm up valves
• MS Pr~50 ksc MS Temp ~350 Deg | HRH Pr~12 ksc | HRH Temp~350 Deg | Soaking of  Turbine @ 360 rpm
• Raise to 3000 rpm |Maintain MS, HRH Pr and Temp by controlling firing |
• Turbine @ 3000 rpm |Electrical Testing | Oil  Injection Test
• Switch ON Field Breaker |AVR on auto | synchronise | Raise Speed Set Point |Pick Load -50 MW | Increase HPBP Set Point (Ensure HPBP, spray valves closing)
• Close Turbine Drains |
• Load 50 MW | MS Pr~54 ksc, HRH~12 ksc, Temp`350 Deg | Start PA & SA Fans (Ensure Path is Clear for FG and Air) | Take !st Mill | BLI >200 TPH | 
• Ready SH, RH spray | Start Second set of ID, FD fans | Ensure switching on of Load Controller at Load > 60 MW | Cut in LPH-2,3 | Cut in all auto controllers | 
• Load : 110 MW | MS~70 ksc/370 Deg , HRH~18 ksc/360 Deg | Charge APRDS from CRH | Ensure energizing of solenoid in Trimming device at load >=100 MW | Cut in 2nd Mill | Limit firing of coal @ 1.5 Tons/ Min
• Load : 160 MW | MS~90 ksc/380 Deg, HRH~20 ksc/380 deg | BLI~580 TPH | Furnace-WB DP> 75 mm WC | Charge HP Heaters | Put Level controllers on auto | start 1st TDBFP and 2nd CEP | cut in 3rd Mill 
• Load : 250 MW | MS~120 ksc, 410 Deg, HRH~26 ksc/400 Deg | BLI ~820 TPH | Start 4th Mill |Start 2nd PA fan
• Load : 320 MW | MS ~125 ksc/420 Deg, HRH ~28-30 ksc/420 Deg | BLI~1040 TPH |start 5th Mill | cut off Oil support | start 2nd TDBFP & Switch off MDBFP
• Load : 405 MW | MS Pr~170 ksc/475 Deg | HRH Pr~40 ksc/475 Deg |BLI~1310 TPH | Cut in 6th Mill |Maintain SH, RH Metal Temp by spray
• Load : 500 MW |MS Pr~170 ksc/535 Deg HRH~42 ksc,535 Deg | BLI~ 1570 TPH