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CHP ELECTRICITYBoiler

Cooling Tower

Coal Mines

GeneratorHP IP LPGT

WATER

STEAM

WELCOME

O.P. JINDAL SUPER THERMAL POWER PLANT (4*250 MW) TAMNAR , RAIGARH (C.G)

FURNACE SAFEGUARD SUPERVISOTY SYSTEM PURUSOTTUM KUMAR

O.P. JINDAL SUPER THERMAL POWER PLANT (4*250 MW) TAMNAR , RAIGARH (C.G)

FSSSThe Furnace Safeguard Supervisory System (FSSS) is designed to ensure the execution of a safe, orderly operating sequence in the start up and shutdown of fuel firing equipment.The FSSS shall be designed to perform the following functions -

Prevent fuel firing unless a satisfactory furnace purge has been completed.

Prevent start-up of the fuel firing equipment unless certain permissive & interlocks have been  completed.

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FSSSMonitor and control the correct

component sequencing during start-up and shut-down of the equipment.

Provide component condition feedback to the operator .

Provide flame supervision when fuel firing equipment is in service and effect of fuel trip upon certain unacceptable firing conditions.

Initiate a MFT of Unit when a certain abnormal operating conditions exist.

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FSSSThe following operational functions are included in FSSS -

Furnace purge supervision.

Secondary air damper modulation, On/Off control and supervision.

Light oil on-off control and supervision.

Heavy oil on-off control and supervision.

Pulveriser and Feeder on-off control and supervision.

Flame scanner intelligence and checking.

Overall Boiler flame failure protection.

Boiler trip protection.3/25/16 4

FSSSFURNACE PURGE-Before any fuel firing can take place (initially or after a Boiler trip) a successful furnace purge cycle must be completed. To start a furnace purge cycle proceed as follows –

Establish AC & DC power to FSSS and the related equipment.

Establish proper drum water level.Place at least one ID and one FD fan in service.Establish airflow between 30% to 40%MCR

through the furnace.

Then check “PURGE READY” light , If the PURGE READY” light does not come then check all purge permissive.

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PURGE PERMISSIVES All HONVs and HOTV Closed

All LONVs and LOTV closed

No Boiler Trip (MFT condition not present)

All Pulverizers Off.

All Feeders Off

All Flame Scanners Sense No Flame

Both PA fans Off

All Auxiliary Air Dampers Modulating

All HAGs Closed

Air Flow > 30 % to 40% of 1080TPH

Press purge PB

DELAY 300 SEC

MFT RESE

T

PURGE COMPL

ETE

PURGE COMPL

ETE

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AND

FURNACE PURGE- When the furnace purge cycle is started by the operator, by pressing “PURGE START” push button, a five minutes purge timer is energized as indicated by the “PURGING" light coming on.At the end of the five minutes, the boiler trip circuit is reset, provided no boiler trip command is present. The "PURGING" light goes out and yellow “PURGE COMPLETE” light comes on. Once the Boiler trip circuit is reset (on purging complete), the close circuits of H.O. trip valve and L.O. trip valve are de-energised permitting the operator to open it as described below -

FSSS

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HOTV

HOTV OPEN INTERLOCKSNo MFTHFO Header temperature satisfactory HFO supply pressure adequateAll HONV’s closedAtomising steam pressure adequateHORV openUnit 24V DC Power supply available

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AND

Open HOTV for HFO recirculating and firing

HOTV CLOSE INTERLOCKS Any HONV not closed

• HFO pressure low OR

• Atomizing steam pressure low

OR

• HFO Header Temperature Lo-Lo for > 2 secs

AND

MFT operated 2/3 logic

Loss of critical power (24V) > 2 Seconds

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OR

HORV OPEN INTERLOCKS

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H O RECIRCULATION VALVE CONTROL –

Before any main fuel can be fired the heavy oil must be brought to proper temperature.This is accomplished by recirculating H.O. through the oil recirculation system by means opening of the H.O.T.V and H.O. recirculation valves (HORV) .FSSS permits the opening of HOTV for oil recirculation purpose following a boiler trip and prior to starting a furnace purge cycle as follows:

1)Depressing the "H.O. recirculation valve open push button" will Open the Recirculation valve (long), provided all the H.O. nozzle valves are fully closed.

2)When the H.O.R.V. is fully open as indicated by the “HORV open “ light (red) being on, depress the "H.O.T.V. open push button". This will start the H.O. recirculation .

LOTV

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LOTV OPEN PERMISSIVE

24V DC power availableAtomising air pressure

adequateLDO header pressure

adequateAll LONVs closedNo auto closing conditions

presentNo MFT

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AND

Open LOTV for oil firing

LOTV CLOSE PROTECTION

• MFT 2/3 operated• LDO header pressure V. Low

.• Atomizing Air press V. Low

with time delay 5sec .AND. any LONV not closed

• Loss of 24V DC (unit critical power)

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OR

LIGHT OIL PAIR MODE START ( ELEVATION AB ) -

Light oil can be fired at elevation AB only and in pair basis Pair firing mode is selected when no feeder is in service. Pairs are

made for the opposite corners. (Pair 1-3 and Pair 2-4) Oil gun is engaged, corresponding scavenge valve is closed,

atomizing air and LO isolation valves are open. To place the light oil guns in service proceed as follows:

• Select light oil firing.• Establish light oil elevation start permit by the following conditions being satisfied.a) No master fuel trip.b) Light oil trip valve proven fully open.

When pair 1-3 start push button is pressed the following events take place 70 seconds counting period is started.

HEA ignitor advances and starts sparking. Atomising air valve opens. LO Nozzle valve for corner -1 opens LO catches fire and flame indication comes. After 15 seconds HEA Ignitor retracts. When the 30 second counting period expires command will go to

corner 3 and same events will take place. Corner 2-4 can also be placed exactly in the same manner.

FSSS

H O PAIR MODE START ( ELEVATION AB ,CD &EF) -

Heavy oil can be fired at elevation AB or CD or EF . Pair firing mode is selected when no feeder is in service. Pairs are

made for the opposite corners. (Pair 1-3 and Pair 2-4) Oil gun is engaged, corresponding scavenge valve is closed,

atomising steam and HO isolation valves are open. To place the heavy oil guns in service proceed as follows:

• Select Heavy oil firing.• Establish heavy oil elevation start permit by the following conditions being satisfied.a) No master fuel trip.b) Heavy oil trip valve proven fully open.

When pair 1-3 start push button is pressed the following events take place 70 seconds counting period is started.

HEA ignitor advances and starts sparking. Atomizing steam valve opens. HO Nozzle valve for corner -1 opens HO catches fire and flame indication comes. After 15 seconds HEA Ignitor retracts. When the 30 second counting period expires command will go to

corner 3 and same events will take place. Corner 2-4 can also be placed exactly in the same manner.

FSSS -

ELEVATION MODE START UP-

Elevation mode of operation is selected when adjacent

feeder is proven.

Oil elevation is placed in service when Pair 1-3 or Pair

2-4 start Push Button is pressed. In elevation mode

also the oil guns are proven on pair basis.

First command goes for placing Pair 1-3 into service

and Pair 1-3 is placed into service in the same way as

in the pair mode.

After the start command has gone to corner 3 a 30 sec.

counting period is started. When 30 sec. counting

period expires then start command goes for corner 2-4

and corner 2-4 are placed into service exactly in the

same manner as in the pair mode.

FSSS -

PAIR MODE SHUTDOWN- When pair 1-3 stop push button is pressed the following

events take placeA 30 second counting period is started

Oil Gun No-1 HONV closes. Scavenging and atomizing steam valve opens. HEA igniter advances and spark remains for 15 seconds. When atomizing steam valve is proven fully open, a 5

minutes counting period starts. When 5 minutes counting period expires scavenge valve

and atomizing steam valve closes and further closing command goes HFO nozzle valves to reinsure that they are fully closed.

When the 30 second counting period expires stop command will go to corner 3 and same events will take place.

Corner 2-4 can be shut-down exactly in the same manner.

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FSSS -

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Post purge excursion protection circuit has been designed in the Furnace Safeguard Supervisory System. It operates as described below:

• When all the following conditions are satisfied, a 5-minute counting period is started.• Light oil trip valve closed.• Elevation AB all LO nozzle valves closed.• Heavy oil trip valve closed.• All elevation all HO nozzle valves closed.• All Feeders off.• Air flow > 30 % MCR.• All scanners show “no flame”.• All Hot air gates closed.• All aux. air dampers modulating• All PA fans off.

• After 5 minute counting period expires, the “Post Purge Fan Trip” memory is set, if very high or very low furnace pressure exists, the post purge fan trip command is issued (for tripping of FD&ID fans). When any HO / LO valve is open, this is reset.

POST PURGE EXCURSION PROTECTION FSS

S -

BOWL MILL

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BOWL MILL

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MILL START PERMISSIVE

Mill start permissive

Mill motor SWGR available

Pulverizer Ignition permit

available

No MFT

Seal air Header to mill under

bowl DP satisfactory

Mill not ‘ON’

Mill ready conditions

Start permit from PLOS Any lube oil pump ON.Any bearing temp. < 65 OCLO tank temp <65 OCLOP discharge press > 0.8kscLO filter DP< 1.5kscTank level OK.LO flow> 120 LPM

Mill Ready Conditions:Bunker outlet gate open, Feeder inlet gate open,MDVs open in all four corners, Mill outlet temp <95 0 CCAG open, Tramp iron hopper valve openNo mill tripPA permit availableAll burner isolation gates openFeeder in remoteStart permit from PLOS

PA permit availablePA header pressure no lo-loFD Fan ON

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A N D

MILL ELEVATION IGNITION PERMIT FOR Mill A AB elevation 3/4 HONVs / LONVs proven open

Boiler load > 30 % and Feeder - B speed > 50 %.

For Mill B AB elevation 3/4 HONVs/LOTVs proven open

Boiler load > 30 % and Feeder A or Feeder C proven with load>50%

For Mill C CD elevation 3/4 HONVs proven open

AB oil elev 3/4 HONVs/ LONVs open and Feeder B at 50%loading

Boiler load > 30 % & either feeder B or Feeder D proven with >50% loading

For Mill D

CD elevation 3 / 4 HONVs proven open

Boiler load > 30 % and either Feeder- C or Feeder- E proven with >50% loading

For Mill EEF elevation 3/4 HONVs proven open

CD oil elev 3/4 HONVs open and Feeder D at 50%loading

Boiler load > 30 % & either feeder -D or Feeder- F proven with >50% loading

For Mill FEF elevation 3/4 HONVs proven open

Boiler load > 30 % & Feeder- E proven with >50% loading

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OR

OR

OR

O

R

OR

O

R

FSSS -By establishing Ignition energy available and pulverizer ready conditions for the respective pulverizer, it may be placed in service as follows:

• Start Pulverizer by pressing its associated "START” push button. First, seal air valve opens, after seal air to bowl DP adequate pulverizer will start.

• When the Pulverizer is proven on as indicated by the (Red) pulverizer "ON" light, open the hot air gate by pressing its "OPEN" button and allow the pulverizer to come up to the temperature.

• When the pulverizer comes up to temperature, (approximately 60 deg. C) Feeder O/L gate open and start the feeder by pressing its associated "START” push button. Coal flow must be proven either by the coal flow detector or satisfactory pulverizer current within 15 seconds, after the feeder is started.

• When the feeder is ON for 50 secs. the feeder speed is released to auto control and the fuel air dampers are opened to modulate as a function of feeder speed.

PULVERIZER START -

PULVERISER TRIP PROTECTION Any Pulverizer discharge valve not open.

Loss of unit critical power (24V DC).

Pulverizer ignition permit is not available .

MFT (See boiler trip section for details).

Loss of primary air (PA Header pressure Very low-390mmwc)

Seal air header to pulverizer differential pressure low (125 mm

WC) .AND. Pulverizer on for more than 60 secs.

Any coal burner of that elevation Manual Isolation Valve not

open.

Lube oil system failed.

Pulveriser failed to start for > 10 secs.

Electrical Trip.

All PA Fans tripped

All FD Fans tripped

When one PA fan or one FD fan trips and three or more pulverizers

are in service, each pulverizer with a 2 sec time delay a trip

command will be given starting from the top most elevation, until

the number of pulverizers remaining in service is reduced to

three.

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OR

FEEDER START PERMISSIVEPulveriser Ready is available

Feeder speed demand at minimum (5%)

Feeder in Remote

Pulveriser ignition permit available

No MFT

Pulveriser ‘ON’

Feeder SAV open

Feeder O/L gate open

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A N D

FEEDER TRIP CONDITION

Ignition energy removed within 180 seconds

of feeder start

Feeder not in Remote

Feeder SAV not open

Pulverizer OFF

MFT

No coal on belt

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OR

BOILER TRIP PROTECTION Both ID Fans Off – 2/3 hardwire contact for each fans from HT SWGR Both FD Fans Off - 2/3 hardwire contact for each fans from HT SWGR Both Emergency Push Buttons Pressed from UCP Furnace Pressure Lo-Lo (< -175 mmWC, 2 / 3 logic ) Furnace Pressure High-High (> + 150 mmWC, 2 / 3 logic) Drum Level Lo-Lo (< - 225 mm, delay 5 seconds, 2/3Tx) Drum Level High-High (> + 225 mm, delay of 10 seconds, 2/3Tx) Total air flow V. Low ( <30%, 324TPH, FT) Loss Of Reheater Protection (Acted 10sec arming) Loss Of unit 220 V DC For > 2 seconds, (LOTV, HOTV, HORV,

Scanner Emergency Damper) Loss of 24V DC -FSSS internal- MFT pannel hardwired trip) Loss of 110V AC 2sec (nozzle valve solenoids, arming-all feeders

off) Unit Flame Failure trip (arming any feeder proven) Loss Of All Fuel (Arming any HO/LO nozzle valves not closed.) Less than fire ball and loss of AC. All Air Heater off

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OR

When the Boiler trips the following events takes place .Boiler trip red

lamp comes on. MFT A ,B & C trip lamp comes on and reset lamp goes off. Cause of trip memory can not be reset till the furnace

purge is completed. F D Fans Control is transferred to manual. I D fans vane position is transferred to manual. Pulverizers and coal feeders are tripped. P A Fans are tripped. HFO & LDO trip valve closes. All HFO Nozzle valves closes. Auxiliary air damper opens and control is transferred to

manual. S/H and R/H spray block valves closes and can not be

opened unless furnace purge is completed. Turbine Trips

BOILER TRIPSFSSS

LOSS OF ALL FUEL TRIP

THE LOSS OF ALL FUEL TRIP CIRCUIT BECOMES ARMED ONCE ANY ONE NOZZLE VALVES LIFTS FROM CLOSED POSITION IN ANY ELEVATION.

ONCE THE TRIP CIRCUIT IS ARMED, LOSS OF FUEL TRIP WILL OCCUR,IF-

ALL FEEDERS ARE OFF.

AND LOTV/HOTV IS NOT OPEN. OR ALL ELEVATION LONV /HONV

CLOSED.

BOILER TRIP PROTECTIONFSSS -

12- UNIT FLAME FAILURE TRIP

RUNNING COAL ELEVATION ADJACENT FIRE BALL SCANNER ARE NOT SHOWING “2/4”FLAME & IT IS NOT SUPPORTED BY “ 3/4 ”OIL GUNS THEN THESE ELEVATION “ NO FLAME ”OR FLAME FAILURE OCCURED. IF THESE CONDITION OCCURED IN ALL ELEVATION THEN UNIT FLAME FAILURE.

BOILER TRIP PROTECTIONFSSS

BOILER TRIP CONDITIONS

ANY FEEDER PROVEN (FEEDER ON >50 SEC.)

FLAME FAILURE TRIP

ELEVATION AB NO FLAME VOTE

ELEVATION BC NO FLAME VOTE

ELEVATION CD NO FLAME VOTE

ELEVATION DE NO FLAME VOTE

ELEVATION EF NO FLAME VOTE

FSSS

REHEATER PROTECTION TRIP

REHEATER PROTECTAION TRIP LOGIC BECOME ARMED WHEN ANY COAL FEEDER PROVENONCE THE TRIP CIRCUIT IS ARMED, REHEATER PROTECTAION TRIP WILL OCCUR, IF

GENERATOR CB OPEN & MS PRESS.>20 KG/CM2 BOILER WILL TRIP AFTER 10 SEC. DELAY

ANY HPBP OR LPBP < 2 %

GENERATOR CB CLOSE BOILER WILL TRIP AFTER 10 SEC. DELAYANY HPCV & HPBP < 2 %

ANY IPCV & LPBP < 2 %

BOILER TRIP CONDITIONSFSSS-

FSSS -

Scanner fan “A” or “B” can be started manually by depressing the respective “START PB”.

Scanner fan “A” or “B” will start automatically whenever the scanner duct to furnace differential pressure goes low (250 mmwc). AND. No MFT .OR. When there is loss of unit critical power (24 V DC).

if one scanner fan fails to start within 5 secs. after receiving the start command, the other scanner fan will start automatically.

Scanner fans A or B can be stopped by depressing the respective “STOP PB” provided there is No start command .AND. Scanner duct to furnace differential pressure is more than the preset value.

When both the FD fans are off .OR. Loss of unit critical power (24 V DC), scanner emergency damper will open automatically. Damper closes automatically when any FD fan is ON.

SCANNER AIR FAN CONTROL -

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FSSS -

FSSS -SEAL AIR FAN CONTROL :-

There are two seal air fans that serve air for mill and feeder sealing, one working and one standby.

• Any seal air fan can be started manually by depressing its “START PB”. This action gives start command to the motor.

• The seal air fan which is not in service is started on Auto command if, Any PA fan is on .AND. Seal air header to cold PA header DP is low for > 10 secs

• The seal air fan “A” will start automatically 5 sec. after the seal air fan “B” trips or fails to start on receiving start command (SA fan “B” starts automatically if SA fan “A” fails to start).

• Any seal air fan can be stopped by depressing its “STOP PB”, provided the following conditions are satisfied.Seal Air Header / Cold Air duct DP not low.AND.Both Seal Air fans on

• Both Seal Air Fans are tripped once Both PA Fans are off > 15 Secs .

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FSSS -

SADC

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FSSS -

FUNCTION• The function of Secondary Air Damper Control System (SADC) is to

proportion the total secondary air around the firing elevation as per the criteria.

• The amount of fuel fired and the no of firing elevations decide the damper position.

• Each wind box assembly is divided into 13 compartments.• There are 6 elevations which houses coal nozzles for firing the main fuel.• There are 3 elevations which houses oil burner assembly• There are two nos. of over fire air compartment at the top of the windbox.

They are designated as OFA-L (Over fire air - Lower) and OFA-U ( Over fire air - Upper) respectively.

• If secondary air is admitted to a fuel compartment in service, it is referred as fuel air(FA).

• Secondary air is admitted to the furnace through air compartments and fuel compartments not in service, is termed as auxiliary air(AA).

• The auxiliary air damper control is separate from the fuel air damper control.

– Aux Air damper position changes to maintain windbox DP– fuel air damper positions versus the fuel feed rate is to be decided for the

type of coal used.

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FSSS -

AUXULIARY AIR CONTROL All elevations of the aux. air dampers will be automatically switched to modulation

control and then commanded to open 100%, if any one of the following conditions exist.

₋ All FD fans are off₋ All ID fans are off₋ Master fuel trip exists₋ Loss of Unit +24 V DC power

Also the auxiliary air control loop is tripped to manual if any of the following conditions exist.

– DP transmitter deviation high.– Windbox to Furnace DP very high (> 240mm WCL).

When the auxiliary air control is placed in the “Auto” mode of operation , the auxiliary air dampers modulate to control wind box to furnace differential pressure at a predetermined set point.

During the furnace purge cycle, all auxiliary air dampers modulate to maintain windbox to furnace differential pressure at a predetermined set point.

When the unit load exceeds 30% of MCR, the following events occurs : The wind box to furnace differential set point is gradually increased as the unit

load is increased. Conversely, the differential pressure set point is gradually decreased as unit load is decreased.

The rate of increase (or decrease) is controlled by the auxiliary damper controller.

The wind-box to furnace differential pressure set point reverts to its original value during putting in auto.

When the “Post Trip Purge Time Expired” command is established and all FD / ID fans are not off and a Master fuel trip” command doesn’t exist, then a 35 seconds counting period is started. After it expires, the “Open All Auxiliary Air Dampers” command is removed from memory.

The auxiliary dampers act as fuel (oil) air dampers when oil firing is taking place and is open to a preset position.

The fuel (oil) elevation dampers are selected to be closed if there is a back up trip in that elevation and adjacent pulverizers are off and “No Boiler Trip” signal is present.

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FSSS -

AUXULIARY AIR DAMPER CONTROLAbove 30% MCR boiler

load, the auxiliary air elevation associated with the main fuel elevation in service modulate to maintain the varying DP. Those not associated with any elevation in service are closed from top to bottom. The closing signal comes from FSSS. When the unit load is increased above 30% MCR, the Aux. air dampers of elev. AB, BC, CD, DE, EF & FF are closed in a timed sequence (10 sec. interval) provided the associated coal elevations are not in service and the associated oil elevations are not in service. The auxiliary air dampers are closed, starting from the top elevation, progressing towards the lowest elevation.

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FUEL AIR DAMPERS CONTROLAll elevations of fuel air dampers are

commanded to open 100% when any one of the following conditions exist. All FD fans are of All ID fans are of Master fuel trip exists . Loss of Unit +24V DC power

When a coal elevation is in service, the associated fuel air dampers modulate as a function of feeder speed as indicated by the associated coal elevation “MODULATING” light coming on.

When the coal elevation is shut down, the associated fuel air dampers are closed, as indicated by a “CLOSED” light.

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OFA DAMPER INTERLOCKS

The two elevations of the over fire air dampers will be automatically switched to “Manual” control and then commanded to open 100%, if any one of the following conditions exist:

• Master fuel trip occurs.• Loss of unit critical power .(+24 VDC)• Both FD fans are OFF.• Both ID fans are OFF.• WB To Furnace DP exceeds 240mm WCL.

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MODULATION OF OFA DAMPERS

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THANK YOU