Interlocks Protections of Boiler 4x600MW

PLANT INTERLOCK AND PROTECTION JPL (4 x 600 MW )

1. MASTER FUEL TRIP PROTECTIONS:

SL NO

PARAMTR TRIP CONDN

ALARM

TRIP TIME DELAY

REMARKS

1 Both ID Fans OFF -- -- -- 3 hardwired contacts for each ID fan (2/3)

2 Both FD Fans OFF -- -- -- 3 hardwired contacts for each FD fan (2/3)

3 Water wall Circulation Incorrect ON DELAY

5 sec4 UCP: EMG PB &

ReleasePressed together

-- -- --

5 Any OWS: EMG trip comd

Initiated & Confirmed

-- -- --

6 Furnace Pressure V LO -- 2/3 Pressure Switches7 Furnace Pressure V HI -- 2/3 Pressure Switches8 Drum Level V LO ON

DELAY 5 sec

2/3

9 Drum Level V HI ON DELAY 10 sec

2/3

10 Total Air Flow V LO -- < 30% -- Flow Transmitters11 Loss of Reheat

ProtectionActed -- -- -- Arming:

12 Unit 220V DC Not Avlbl 2 sec 220V DC for LOTV solenoids13 Unit 24V DC

(FSSS internal)Not Avlbl -- -- -- 24V for MFT Panel

Hardwired trip14 Less than FB & loss of

AC in any elevation in service

Loss of 110V AC

-- -- 2 sec 110V AC for nozzle valve solenoidsArming: All feeders off

15 Unit Flame Failure Trip

Activated -- -- -- Arming: Any feeder proven

16 Loss of All Fuel Trip Activated -- -- -- Arming: Any LO nozzle valve not closed

17 Both Air Heaters off OFF -- -- 5 sec for indiv SAH

Air Heater OFF = Main motor OFF & Air pressure Low

18 All BFP OFF 10 secNOTE: All Trip Conditions are individually sensed by each MFT panel.

Final 2/3 Logic for Master Fuel Trip is hardwired in Purge Panel.

1

PLANT INTERLOCK AND PROTECTION JPL (4 x 600 MW ) LOSS OF ALL FUEL TRIP (Arming: Any Nozzle valve Not closed )

Note: All conditions to be satisfied for trip

SN PARAMETER TRIP CONDN ALARM VAL TRIP VAL REMARKS

1. Loss of all fuel trip arming* AND 2. All feeders Off AND3. (LOTV Not Open) OR All EL.

LONV closed OR All Elevation Backup Trip

* Loss of all fuel Trip Arming is done when any elevation any nozzle valve not closed signal becomes true.

UNIT FLAME FAILURE TRIP (Arming: Any Feeder proven)

SN PARAMETER TRIP CONDN ALARM VAL

TRIP VAL REMARKS

Flame failure trip arming* & All Elevation A-H Voted no flame **

-- --

*Flame failure trip arming is done when any of the feeders is proven.** No flame VOTING LOGIC For Elevation A1. Feeder A STOP for More Than 2 sec OR2. EL AB Start And Loss of 110V AC Power for more than 2 sec OR3. EL AB 2/4 Light oil Nozzle V/V Not Proven & EL. AB 3/4 FB scan No flame.

LESS THAN FIREBALL OR LOSS OF AC IN ANY ELEV IN SERVICE

SN PARAMETER TRIP CONDN ALARM VAL

TRIP VAL REMARKS

1. All Feeders Off AND2. Any of the Oil EL.(AB, CD, EF, GH) Start and Loss of 110V AC ( ON TD 2 sec)

-- --

2


FSSS : PURGE PERMISSIVES:

S. No

PARAMETER REQ. STATUS SET VALUE

REMARKS

All PA Fans OFF --LOTV Closed --All Elevation All LONV Closed --All Feeders OFF --All Hot Air Gates Closed --All Elevations Discr Scanners

No Flame --

All Elevations Fireball Scanners

No Flame --

All Auxiliary Air Dampers Modulating Taken from inlet pressure switches for each damper

Total Air Flow > 30%< 40%

> Tph< Tph

100% = Total Air Flow at MCR =Tph

No Boiler Trip True MFT condition not present (but MFT Not reset)

NOTE: Purge Timer = 9 minutes, Post-Trip Purge Timer = 5 minutes.

LIGHT OIL TRIP V/V :

OPENING PERMISSIVES: AUTO CLOSING CONDITIONS:

1.1 Depress the LO trip valve OPEN pushbutton AND No MFT AND Light oil supply pressure adequate AND All LONV closed OR

2.1 Depress the LO trip valve OPEN pushbutton

AND 2.2 LFO Return oil trip valve OPEN

1.1MFT AND LO Return Trip valve not open

OR2.1 Atomizing air pressure very low AND any

light oil nozzle valve not closed AND No LO start/stop in any elevation AND LO Return valve not open

OR

2.2 LO header pressure very low AND any light oil nozzle valve not closed AND LO Return valve not open

3


OR2.3 Loss of 24V DC supply.

LO ELEVATION:

LO ELEVATION START PERMIT: LO ELEVATION TRIP CONDITIONS:

1. Light oil selected2. No MFT3. LOTV proven fully open4. Pulverizer start permit

4.1 Nozzle tilt horizontal AND air flow <40% MCR

OR4.2 Any oil elevation is in service

OR 4.3 Any feeder On.

AND 4.4 No MFT.

1. Master Fuel Trip Operated

OR 2. LOTV Not Opened

LIGHT OIL RETURN TRIP VALVE:

OPENING PERMISSIVES: AUTO CLOSING CONDITIONS:1. LFO return trip valve open PB pressed

AND2. All elevation LONV closed.

AND3. No auto closing conditions.

1. All El. LFO Nozzle valves not closed

OR2. LFO return trip valve close PB pressed

OR3. LFO Trip Valve closing command AND LFO

Return valve not closed

4


LIGHT OIL NOZZLE VALVE:

OPENING PERMISSIVES: AUTO CLOSING CONDITIONS1. The corner is not in scavenge

AND2. Atomizing air nozzle valve is proven open

AND3. None of the corner trip condition is present

AND4. HEA ignitor spark rod is in advanced position

AND5. Non existence of corner LO nozzle valve is

open

AND6. Non Existence of the condition in which LO

Nozzle valve open AND Discriminating scanner shows no flame

1. Scavenge start.

OR2. LO Nozzle valve open AND discriminating

scanners show no flame.

OR3. Light Oil Trip*

OR4. Loss of 24V DC in El. AB

AIR NOZZLE VALVE:

OPENING PERMISSIVES: AUTO CLOSING CONDITIONS1.1 HEA Rod advanced AND oil gun engaged

AND LO corner start AND EL. AB light oil selected AND Atomizing air manual isolation valve open AND scavenge valve closed.

OR1.2 Disc. Scanner Flame

AND2. LO nozzle valve closed AND Start scavenge

AND El. AB Light oil selected AND Light oil trip not available

Light oil Trip*

*Conditions for Light Oil Trip

5


1. Elevation AB back up trip OR LGM switch in off OR Oil gun not engaged

OR2.1 LO manual isolation valve not open OR Atomizing air manual isolation valve not open OR discriminating

scanner shows no flame.

AND2.2 LO corner not start AND Non availability of El. AB light oil selected and start scavenge.

OR 3.1 Atomizing air manual isolation valve not open OR LO nozzle manual isolation valve not open.

SCAVENGE NOZZLE VALVE:

OPENING PERMISSIVES: AUTO CLOSING CONDITIONS1. Light oil trip not present

AND2. Atomizing air nozzle valve open

AND3. Open scavenge valve signal available

1. Atomizing air nozzle valve not open

AND2. Close scavenge nozzle valve present.

6


SECONDARY AIR DAMPER CONTROL:

AUX. AIR DAMPER AUX. AIR DAMPER OPEN CONDITION: (APPLICABLE TO AB, BC, CD, DE, EF, FG, GH, AND HH)

AUXIALIARY AIR DAMPERS CLOSING CONDITION (For El. AB)

1. Both FD fans are OFF2. Both ID fans are OFF3. Master fuel trip exists.4. Loss of unit critical power (+24V DC)

1. MILL A & B Off &2. No MFT &3. *Boiler Load index >30 % &4. EL AB back up trip

OR5. El. AB Started AND El. AB start time not expired

AND Boiler load is not >30%.

* Once the Boiler Load Reaches > 30% the aux air dampers close in a timed sequence starting from top with a time delay of 10 Sec provided all other conditions for closing are satisfied.

Also the auxiliary air control loop is tripped to manual if any of the following conditions exist. DP transmitter deviation high. DP transmitter failed. Furnace to Wind box DP very high (> 240mm WCL).

FUEL AIR DAMPERS (A-K) & OFA DAMPER OPENING CONDITIONS:

FUEL AIR DAMPERS (A-K) OPENING CONDITION

FUEL AIR DAMPERS (A-K) CLOSING CONDITION

1. Both FD fans are OFF2. Both ID fans are OFF3. Master fuel trip exists.4. Loss of unit critical power (+24V DC)

1. Post trip purge time expiredAND

2. ID fan off OR FD fan off OR MFT not exist.

Fuel (coal) air damper control loop will be tripped to manual if any of the following conditions exist:

Feed rate signal failed Open fuel air damper command (From FSSS) Close fuel air damper command (From FSSS)

*The opening command is removed once the post purge time has expired and all opening conditions are removed instantaneously for fuel air dampers F-K and for A-E with 30 sec time delay. The close command is extended with a time delay of 50 sec after the corresponding feeder is out of service.

7


ID FAN : ID FAN VFD CHANNEL-1 DRIVE START PERMISSIVES:

Sl No

PARAMETER REQUIRED STATUS

SET VALUE

REMARKS

1. Ch-1 SRC Breaker Not Disturbed --2. Ch-1 SRC Breaker ON from SWGR --3. VFD Ch-1 No Alarm --4. VFD Ch-1 Ready --5. VFD Ch-1 Start Permissive Available -- From VFD6. ID Fan Ch-1 auxiliary Supply Healthy --7. Ch-1 No Fault --8. VFD System Aux Supply OK --

9. Reg. Damper Pos Min & I/L Gates Closed & O/L Gates Closed (OR) ID Fan VFD Ch-2 ON

10. Either LOP (A or B) ON --11. ID Fan Exciter Winding temp Not HI --12. Lub oil pressure OK ≥0.8 ata13. Fan/Mtr Brg temp. Not HI --14. Mtr Wdg temp. Not HI --15. Lub oil temp. at cooler O/L Not HI --16. Lub oil tank level Not LO --17. Flue gas path available OR Other ID Fan ON

ID FAN VFD CHANNEL-2 DRIVE START PERMISSIVES:

Sl No


SET VALUE REMARKS

1 Ch-2 SRC Breaker Not Distbd2 Ch-2 SRC Breaker ON3 VFD Ch-2 No Alarm4 VFD Ch-2 Ready5 VFD Ch-2 Start Permissive Available6 Ch-2 No Fault7 VFD System Aux Supply OK --8 Reg Damper Pos Min & I/L Gates Closed & O/L Gates Closed (OR) ID Fan VFD Ch-1 ON9 Either LOP (A or B) ON10 ID Fan Exciter Winding temp Not HI11 Lub oil pressure OK ≥0.8 ksc12 Fan/Mtr Brg temp Not HI13 Mtr Wdg temp Not HI14 Lub oil temp at cooler O/L Not HI15 Lub oil tank level Not LO16 Flue gas path available OR

Other ID Fan ON

8

PLANT INTERLOCK AND PROTECTION JPL (4 x 600 MW ) VFD CHANNEL-1 TRIP PROTECTIONS:

SL NO

PARAMTR TRIP CONDN

ALARM VAL

TRIP VAL REMARKS

1) VFD Ch-1 FAULT /VFD2) Ch-1 SRC Breaker Elect Trip3) Fan/Mtr Brg temp V HI4) Mtr Wdg temp V HI5) Fan/Mtr Brg

VibrationV HI ≥9.9 mm/s

6) IDF-A Post Purge TRIP /FSSS7) Fan ON* for 120 sec & ID fan A

outlet gate 1 & 2 closed*VFD Ch-1or 2 min speed achieved

8) Fan ON* for 120 sec & I/L gate 1 & 2 closed

*VFD Ch-1or 2 min speed achieved

9) Both ID and both FD ON(off time delay 5 sec) & FD-A trip

FD to ID inter trip

VFD CHANNEL-2 TRIP PROTECTIONS:

SL NO

PARAMTR TRIP CONDN

ALARM TRIP REMSET VAL SET VAL

1) VFD Ch-2 FAULT /VFD2) Ch-2 SRC Breaker Elect Trip3) Fan/Mtr Brg temp V HI4) Mtr Wdg temp V HI5) Fan/Mtr Brg

VibrationV HI ≥9.9 mm/s

6) IDF-A Post Purge TRIP /FSSS7) Fan ON* for 120 sec & ID fan A

outlet gate 1 & 2 closed*VFD Ch-1or 2 min speed achieved

8) Fan ON* for 120 sec & I/L gate 1 & 2 closed

*VFD Ch-1or 2 min speed achieved

9) Both ID and both FD ON(off time delay 5 sec) & FD-A trip

FD to ID intertrip

ID FAN LOP-A:

Sl No


SET VALUE REMARKS

START PERMISSIVES1) Lub Oil Tank Lvl Not Low2) ID fan A LOP A MCC Not Distbd.

AUTO STARTLOP-B Tripped From LOP-B logicID Fan lub oil pressure low AND <0.6 ata 5 sec on delay

9


LOP-B ONID fan LOP order START AND LOP-B off

STEP#1 To be checked in SGC

STOP RELEASE1) ID Fan OFF 30 min. delay2) IDF-A LOP:B- ON & Lub Oil Pr OK ( > 0.8

ksc) AUTO STOP1) LOP order STOP STEP#55 To be checked in SGC

ID FAN LOP-B:

**Note: Same as ID fan LOP A.

10

PLANT INTERLOCK AND PROTECTION JPL (4 x 600 MW ) FD FAN START PERMISSIVES:

Sl No


SET VALUE REMARKS

1 FD Fan OFF(From SWGR)2 Lube oil tank level Not Low Time Delay 2 sec3 FD Fan motor winding

temperatureNot HIGH

4 FD Fan Electric Trip Not Present5 Atleast One ID Fan ON6 FD Fan/Motor Bearing

temperature Not HIGH

7 FD Fan Control Oil Pressure OK >8ata8 FD Fan lube oil pressure OK <4 bar9 FD Fan Outlet Gate Closed10 Any of the LOP ON(MCC)11 FD Fan blade pitch Control Minimum(ACS)12 FD Fan blade pitch Control Manual13 SWGR Available14 SWGR not disturb

TRIP PROTECTION:

SNO PARAMTR TRIP CONDN ALARM VAL TRIP VAL

1 FD Fan post Purge trip From FSSS 2 FD fan /Motor Bearing

TemperatureVery HIGH T*+5 T*+10

3 FD Fan Motor Winding Temperature

Very HIGH T*+5 T*+10

4 FD Fan/ Motor Vibration Very HIGH 5 Both ID fan Off OFF(SWGR)

6 FD Fan ON (TD 5sec) AND FD Fan outlet Gate Closed

7 Both FD fan ON AND one ID fan OFF

11


FD FAN LOP-A:

S NO

PARAMETER REQ. STATUS

SET VALUE REMARKS

PERMISSIVE STARTPA Fan Lub Oil Tank Level Not low

AUTO STARTOther LOP Tripped LOP was running &OFF status appeared without

manual OFF command.Other LOP ON (TD 60 sec) & Control oil pressure LOW <5 barLOP Order start command When other LOP is OFF


AUTO STOPLOP Order STOP STEP#54 To be checked in SGC

PERMISSIVE STOPFDF OFF (TD 30 min)Other LOP ON AND FD Fan Control Oil Pressure OK

>8ata

FD FAN LOP-B:

**Note: Same as FD fan LOP A.

FD FAN OUTLET GATE:

Sl No


SET VALUE REMARKS

PROTECTION OPEN:Both FD Fans OFF 15 min pulse

AUTO OPEN:FD Fan ON for (T sec)FD fan O/L gate open STEP#53 To be checked in SGCFD fan O/L gate open STEP#5 To be checked in SGCFD fan O/L gate open From FD fan B

logicAUTO CLOSE: (Permissive: FD Fan OFF)

Other FD Fan ON &Other FD Fan Outlet gate Open &FD Fan OFF

PERMISSIVE CLOSE:FD fan O/L gate close STEP#52 To be checked in SGC

12


FD fan O/L gate close STEP#2 To be checked in SGCFD fan O/L gate close From FD fan B

logic

PA FAN START PERMISSIVES:

Sl No


SET VALUE REMARKS

1 PA- Fan OFF(From SWGR)2 PA Fan control oil pressure OK >25 bar3 PA Fan electrical trip Not present4 Lub oil tank level Not less than min5 Path for PA fan Available6 PAF Fan/motor vibration Not high7 PAF fan/motor bearing temp Not high8 PAF motor winding temp Not high9 Any of the LOP ON10 PAF start permissive from

FSSS11 PA Fan outlet air gate Closed12 PA Fan Blade Pitch control

damperMinimum(ACS)

13 PA Fan Blade Pitch control damper

Manual(ACS)

14 Both of the FD fan ON OR (Either FD FAN On & Other PA FAN Off)

15 SWGR Available16 SWGR not disturb

TRIP PROTECTION:

SNO PARAMTR TRIP CONDN ALARM VAL TRIP VAL

1 MFT operated(From FSSS)2 PA fan /Motor Bearing

TemperatureVery HIGH T*+5 T*+10

3 PA Fan Motor Winding Temperature

Very HIGH T*+5 T*+10

PA Fan/ Motor Vibration Very HIGH 6.3mm/s 9.9mm/s4 FD Fan A AND B OFF(SWGR)

13


5

PA Fan ON for 5sec AND PA Fan Discharge Air Gate Closed

*Actual Running Temperature observed

PA FAN LOP-A:

S NO


SET VALUE REMARKS

PERMISSIVE STARTPA Fan Lub Oil Tank Level Not low

AUTO STARTOther LOP Tripped LOP was running &OFF status appeared without

manual OFF command.Other LOP ON for 30 sec &Oil pressure after filter (time delay)

<15 barTime delay 30 sec

LOP Order start command When other LOP is OFF


AUTO STOPLOP Order STOP STEP#53 To be checked in SGC

PERMISSIVE STOPPAF OFF (TD 30 min) From SWGROther LOP ON from MCC AND PA Fan Control Oil Pressure OK

>25 bar

PA FAN LOP-B:

**Note: Same as LOP A.

PA FAN OUTLET DAMPER:

S NO


SET VALUE REMARKS

AUTO OPEN1 PA Fan ON(Time Delay

2sec)2 PA Fan outlet Air Gate

OpenSTEP#4 OR 5 To be checked in SGC

AUTO CLOSE1 PA Fan Outlet Air gate

CLOSESTEP#2 To be checked in SGC

2 PA Fan Outlet Air gate CLOSE


14


3 PA Fan Outlet Air gate CLOSE

From PAF B logic

4 PA Fan OFF (Time Delay 10sec)

From SWGR

SEAL AIR FAN A:

START PERMISSIVES SHUT DOWN CONDITIONS1. Seal air fan A start PB is pressed

OR2. Any PA fan ON AND Seal air header/Cold air DP

low for >10 sec

OR3. Auto Start Seal air fan A & not Seal air fan B

1. All PA fans off for 15 sec

OR2. Seal air fan A stop PB is pressed when

Seal air header/ cold air duct DP not low AND Seal air fan B stop push button not pressed AND Both seal air fans ON

OR3. Auto start Seal air fans A & B command

for more than 10 sec.

NOTE- One Seal air fan fails to start within 5 sec after receiving the start command; the other scanner fan will start automatically.

SEAL AIR FAN B: Note: Same as Seal air fan A.

SCANNER AIR FAN A:

START CONDITIONS SHUT DOWN CONDITIONS1. Scanner air fan start PB is pressed

OR2. No MFT AND Scanner duct/Furnace DP

low(<150mmWC) for 5 secOR

3. One scanner fan fails to start within 5 sec after receiving the start command; the other scanner fan will start automatically.

1. Scanner air fan stop PB is pressed whenScanner duct/Furnace DP low AND No MFT conditions are not present.

2. Both Seal air fans are tripped when Both PA fans are off for more than 15 sec.

3. Both Seal air fans are tripped when Both seal air fans have unsuccessful start command

15

PLANT INTERLOCK AND PROTECTION JPL (4 x 600 MW ) SCANNER AIR FAN B:Note: Same as Scanner air fan B.

AIR PRE HEATER:

START PERMISSIVES For AH-A:

Sl No PARAMETER REQUIRED STATUS

SET VALUE

REMARKS

1. AH-A off2. AH-A Elect motor MCC not disturbed3. AH-A support brg oil temp Not V. High4. AH-A guide brg oil temp Not V. High5. AH-A supp brg LOP-A MCC not disturbed6. AH-A supp brg LOP-B MCC not disturbed7. AH-A guide brg LOP-A MCC not disturbed8. AH-A guide brg LOP-B MCC not disturbed9. AH-a power supply for air motor

solenoid valveAvailable

10. AH –A air pressure before air motor solenoid

Not low >5Kg/cm2

11. EP Path Available

AH ELECTRICAL MOTOR:

Sl No


SET VALUE

REMARKS

ON RELEASE:AH-A GB oil temp Not V.HI <70 oCAH-A SB oil temp Not V.HI <70 oCAH-A electrical motor MCC not

disturbAUTO ON:

AH-A SGC Startup Sequence Step#04 -- To be checked in SGCAUTO OFF: (Rel always available)

AH-A SGC Shutdown Sequence Step#53 -- To be checked in SGC

AH AIR MOTOR:

Sl No


SET VALUE

REMARKS

ON RELEASE:AH-A GB oil temp Not HI <70 oC

16


AH-A SB oil temp Not HI <70 oCAH-A Elect Motor OFF --

AUTO ON:AH-A Elect Motor Tripped -- 5 sec pulse

AUTO OFF: (Rel always available)AH-A Elect Motor ON --AH-A SGC Shutdown Sequence Step#53 -- To be checked in SGC

AH SUPPORT BEARING LOP:

Sl No


SET VALUE

REMARKS

ON RELEASE:Support Bearing oil temp HighSupport bearing LOP-A MCC not

disturbedAUTO ON:

AH SGC Startup Sequence Step#01 -- Either SB LOP ONTo be checked in SGC

AH ON ANDAH support bearing oil temp is high ANDOther Support bearing LOP OFF (2 sec pulse)

--

AH ON AND Other SB LOP ON for 30 sec ANDSB Oil flow LowAH ON & Other SB LOP ON to OFF

--

AUTO OFF: (Rel always available)AH SGC Shutdown Sequence Step#56 -- To be checked in SGCAH SB Oil temp

Low 30 sec delay, 5 sec pulse

AH GUIDE BEARING LOP:

Sl No


SET VALUE

REMARKS

ON RELEASE:Guide Bearing oil temp high HighGuide bearing LOP-A MCC not

disturbedAUTO ON:

AH SGC Startup Sequence Step#01 -- Either GB LOP ONTo be checked in SGC

17


AH ON ANDAH Guide bearing oil temp is high ANDOther Guide bearing LOP OFF (2 sec pulse)

--

AH ON AND Other GB LOP ON for 30 sec ANDGB Oil flow LowAH ON & Other GB LOP ON to OFF

--

AUTO OFF: (Rel always available)AH SGC Shutdown Sequence Step#56 -- To be checked in SGCAH GB Oil temp

Low 30 sec delay, 5 sec pulse

AH FLUE GAS I/L DAMPER(1 & 2):

Sl No


SET VALUE

REMARKS

AUTO OPEN:AH FG I/L damper open OR Step#11 -- To be checked in SGCAH FG I/L damper open From AH-B

logicTo be checked in SGC

PROTECTION OPEN:AH-A ON for 5 sec AND MFT Operated

PERMISSIVE OPEN:AH SA O/L Damper open ANDAH SA I/L Path open ANDAH PA I/L Damper open ANDAH PA O/L Damper open ANDBoiler not ON.

AUTO CLOSE:AH Flue gas damper close Step#51 To be checked in SGCAH Flue gas damper close From AH-B


AH-A OFF AND AH-B AvailablePERMISSIVE CLOSE:

Both ID Fans off

AH FLUE GAS O/L DAMPER (1 & 2):

Sl PARAMETER REQUIRED SET REMARKS

18


No STATUS VALUEAUTO OPEN:

AH FG O/L damper open OR Step#10 -- To be checked in SGCAH FG O/L damper open From AH-B


PROTECTION OPEN:AH-A ON for 5 sec AND MFT Operated from FSSS

PERMISSIVE OPEN:Boiler fire not ON OR AH-A ON

AUTO CLOSE:AH Flue gas O/L damper close Step#51 To be checked in SGCAH Flue gas O/L damper close From AH-B


(AH-A OFF OR Tripped) AND AH-B Available

PERMISSIVE CLOSE:Both ID Fans off

AH PA I/L AND O/L* DAMPER:

Sl No


SET VALUE

REMARKS

AUTO OPEN:AH-A PA I/L damper open OR Step#5 -- To be checked in SGCAH-A PA I/L damper open From AH-B


PERMISSIVE OPEN:AH-A ON

AUTO CLOSE:AH-A PA I/L damper close Step#52 To be checked in SGCAH-A PA I/L damper close From AH-B


PERMISSIVE CLOSE:Both ID fans OFFAH-A FG I/L Damper 1 & 2 closed AND AH- B available AND (AH-A

19


OFF OR Tripped)PROTECTION CLOSE:

Both PA fans OFF From SWGR 900 sec pulse

* For PA O/L Damper control logic PA I/L Damper shall be replaced by PA O/L Damper.

AH SECONDARY AIR SCAPH-A I/L AND O/L** DAMPER:

Sl No


SET VALUE

REMARKS

AUTO OPEN:AH-A SCAPH-A I/L damper open OR Step#9 -- To be checked in SGCAH-A PA SCAPH-A I/L damper open From AH-B


PROTECTION OPEN:MFT Operated 900 sec. pulse

AUTO CLOSE:AH-A SA SCAPH-A I/L damper close Step#09 To be checked in SGC (Start

Sequence)AH-A SA SCAPH-A I/L damper close Step#52 To be checked in SGC

(Shutdown Sequence)AH-A SA SCAPH-A I/L damper close From AH-B

logicPERMISSIVE CLOSE:

AH-A SA SCAPH-A BP Damper openedAH-A FG I/L Damper 1 & 2 closed

**For SA SCAPH-A O/L Damper control logic SA SCAPH-A I/L Damper shall be replaced by SA SCAPH-A O/L Damper.

AH SECONDARY AIR SCAPH-A BP DAMPER:

Sl No


SET VALUE

REMARKS

AUTO OPEN:AH-A SCAPH-A BP damper open OR Step#9 -- To be checked in SGCAH-A PA SCAPH-A BP damper open From AH-B


PROTECTION OPEN:MFT Operated 900 sec. pulse

AUTO CLOSE:AH-A SA SCAPH-A BP damper close Step#09 To be checked in SGC (Start

20


Sequence)AH-A SA SCAPH-A BP damper close Step#52 To be checked in SGC

(Shutdown Sequence)AH-A SA SCAPH-A BP damper close From AH-B

logicPERMISSIVE CLOSE:

AH-A SA SCAPH-A I/L Damper opened ANDAH-A SA SCAPH-A O/L Damper openedAH-A FG I/L Damper 1 & 2 closed

AH SA O/L DAMPER:

Sl No


SET VALUE

REMARKS

AUTO OPEN:AH SA O/L damper open OR Step#5 -- To be checked in SGCAH SA O/L damper open From AH-B


PROTECTION OPEN:AH-A ON for 5 sec AND MFT Operated

PERMISSIVE OPEN:Boiler fire not ONAH-A ON

AUTO CLOSE:AH SA O/L damper close Step#52 To be checked in SGCAH SA O/L damper close From AH-B


PERMISSIVE CLOSE:Both ID Fans offAH-A FG I/L Damper 1 & 2 closed AND AH-B available AND(AH-A off OR tripped)

COAL MILL

START PERMISSIVE FROM PLOS AUTOMMATIC MILL TRIP CONDITION FROM PLOS

1. Lub oil temp adequate (>30oC) 1. Both lube oil pumps are not ON for more

21


2. Lub oil pump ON for more than 60 sec AND lub oil pressure a cooler outlet is NOT LOW (>0.8 bar)

3. Lube oil filter not dirty (< 2 bar)4. Lube oil flow to gearbox is NOT LOW

(>200LPM)5. Any bearing temperature of gearbox is within

alarm limits (<75oC)

than 2 sec2. Lub oil pump ON and lube oil pressure is

< 0.5 bar after cooler is very low with a time delay of 15 sec.

3. Lube oil temp after cooler is very high (>65oC)

4. Lube oil flow to gearbox is very low (<175 LPM)

COAL MILL : Start Permissive1 Mill Ready Conditions 1. Pulverizer/feeder start permit

2. Pulverizer discharge valve open3. Pulverizer outlet temperature not high4. Cold air gate open OR Pulverizer ON5. Tramp iron hopper valve open6. Primary air permit OR Pulverizer ON7. Pulverizer no unsuccessful auto start8. All burner isolation valve open9. Feeder switch in remote10. Pulverizer no trip11. Lube oil system healthy12. Feeder inlet gate OPEN13. Bunker outlet gate OPEN.

2 Mill Start Permissive 1. (Nozzle tilts horizontal AND Air flow is less than 40% MCR) OR Any oil Elevation in Service OR Any feeder ON.

2. No MFT

MILL PROTECTIONS:1 Mill Protections 1. Pulverizer failed to start >10 sec

2. Loss of PA fan- trip pulverizer H, G, F, E3. Electrical trip4. Pulverizer discharge valve not open5. Pulverizer ignition permit is not available AND support

ignition required6. Hot air gate closed AND cold air gate not open7. Seal air to pulverizer differential pressure low ( <125

mmwc) AND Pulverizer ON for more than 60 sec.8. Any burner isolation gate not open9. Loss of primary air10. Loss of unit +24V DC

22


11. Lube oil system failed

2 Loss Of Primary Air Conditions:

1. PA HDR Pressure very low 2. All PA or FD fans off and any Pulverizer on3. PA HDR pressure low (TD 5 sec)

3 Description Of PA Trip: (Applicable to Mills H, G, F, E Progressive time Delay of 2 sec starting from Mill H for which, trip is instantaneous)

5 or more MILL on & any one of the following Any FD fan offAny PA fan not off

MILL HOT AIR GATE: OPENING PERMISSIVES: AUTO CLOSING CONDITIONS:

1. Pulveriser ONAND

2. Close hot air gate not presentAND

3. Pulveriser auto start-open hot air gateORPulverizer manual mode AND Hot air gate open PB is pressed

1. Pulverizer offOR

2. Loss of 24 V DCOR

3. Close hot air gate with 30 sec delay ##[Hot air gate not closed OR Pulverizer outlet temp 100oCANDClose hot air gate auto command OR HAG close pulse OR Auto pulveriser unsuccessful start OR (Feeder ON too 5 sec AND Feeder OFF)]

MILL COLD AIR GATE:

OPENING CONDITIONS: AUTO CLOSING CONDITIONS:1. Mill outlet temp adequate (90oC) AND pulveriser

is ONOR

2. Cold air gate PB is depressed.

1. Pulveriser ON AND mill Outlet temp is low(75oC)OR

2. Pulveriser OFF AND CAG close PB is pressed.

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BCW PUMP : START PERMISSIVES:S N

PARAMETER REQ. STATUS SET VALUE REMARKS

1 Pump prot criteria Not present --2 Pump LP cooling water flow Not low >8TPH3 Diff Temp between BCW pump casing

& suction manifoldNot high < 50oC

4 Pump Motor Cavity temp OK >2oC &<63oC5 Pump Disch Valve Stem-1 Open --6 Pump Disch Valve Stem-2 Open --7 Pump Switchgear Available Remote & in service8 Boiler drum vent valves Closed --9 Pump Switchgear Not disturbed --10 CW supply to BCW pumps Normal Emergency CW tank

level OK

TRIP PROTECTIONS:

S N PARAMETER TRIP CONDN ALARM VAL

TRIP VAL REMARKS

1 Pump Motor Cavity temp V HI >63 oC 66 oC2 Pump Disch Valve Stem-1 Not Open -- --3 Pump Disch Valve Stem-2 Not Open -- --

PUMP AUTO START (in standby selection):

S N


SET VALUE

REMARKS

1 Any other running BCWP (B OR C) Tripped --2 BCWP-C ON for 30 sec & DP low (5 sec delay) * (18 psi for >60% MCR)3 BCWP-B ON for 30 sec & DP low for 10 sec &

BCWP-C Not ON (2 sec delay)* (18 psi for >60% MCR)

ECW PUMP (BOILER): START PERMISSIVES:S N PARAMETER REQ.

STATUSSET

VALUEREMARKS

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1 Boiler ECW pump suction header pressure Adequate2 Boiler ECW pump Suction Valve OPEN3 Boiler ECW Pump MCC Not disturbed > 2.5 Ksc 2 / 3 Logic(LVM)4 ECWP Selected Stdby & Its Discharge Valve Open OR

Its Disch.Valve Close

TRIP PROTECTIONS:

SNO

PARAMTR TRIP CONDN

ALARM VAL

TRIP VAL

REMARKS

1 ECW Pump ON and Off both commands from MCC

2 ECWP ON for 10 sec & Its Disch. Valve Not Open

TD= 2 sec

3 ECWP Disch. Hdr. Pr. V.HI4 ECWP Suct. Hdr. Pr. V.LOW

DIFFERENT LEVELS

DRUM LEVEL

( FROM HYFRASTEP )S No PARAMETER VALUE REMARKS

1 NORMAL LEVEL - 225 mm2 HIGH LEVEL ALARM + 125 mm 6th PORT FROM TOP3 HI HI LEVEL TRIP +250 mm 2nd PORT FROM TOP4 LOW LEVEL ALARM - 175 mm 6th PORT FROM BOTTOM5 LO LO LEVEL TRIP - 375 mm 2nd PORT FROM BOTTOM

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Documents

Interlocks Protections of Boiler 4x600MW