modulating control(operating procedure)

8/9/2019 Modulating Control(Operating Procedure)

1/32

B N G P K O N G

3 4 M O D U L T IN G C O N T R O L S

O P E R T I N G P R O C E D U R E S

C O N T E N T S

CONTENTS INS 210392

1

UNIT MASTER

2 AIR

FLOW

3

FLUE GAS 02 AND

CO CONCENTRATION

4

GAS

FUEL

FLOW

5

OIL

FUEL

FLOW

6

GOVERNOR

POSITION

7

FURNACE PRESSURE

ID

FAN

DAMPERS

8 ID FAN SPEED

9

DRUM LEVEL MOTOR BOILER FEED PUMPS

1

DRUM LEVEL TURBINE BOILER FEED PUMPS

11

DEAERATOR

LEVEL

CONDENSATE PUMPS

12

CONDENSER LEVEL

13

SECONDARY SUPERHEATER OUTLET TEMPERATURES

14

TERTIARY [FINAL] SUPERHTR OUTLET

TEMPERATURES

15

REHEAT

STEAM

TEMPERATURE

[GAS RECIRC]

16

REHEAT

STEAM

TEMPERATURE

[SPRAYS]


2/32

B A N G

P A K O N G

3 4

D C I S

O P E R A T I N G

M O D U L A T I N G

P R O C E D U R E

:

U N I T M A S T E R

C O N T R O L S

MASTER.INS

030992

--------------------------------------------------------------------

SYSTEM

BOILER-TURBINE COORDINATION

CON .T VARIABLE

MEGAWATTS, PRESSURE

CONTROL DEVICE

GOVERNOR, FUEL AND AIR SUBLOOPS

SET

VALUE

REQUIRED UNIT OUTPUT AND PRESSURE

GSM

PB

UNIT

MSTR

GROUP

DISPLAY

001

UNIT MASTER

TX DEVN DISPLAY

089

MASTER & AIR XMTRS

A ) P E R M I S S I V E S

(1)

Coordinated

Mode:

Air Flow,

Fue l

Flow, Governor ,

Main

Steam

Temperature ,

Feedwater Flow

and

Condensate Flow cont ro l s se lec ted to AUTO

(2)

Boiler

Follow Mode: Air Flow, Fuel Flow and Governor (opt ional) se lec ted

to

AUTO

(3)

Base

Input Mode:

Air Flow,

Fuel Flow and Governor (opt ional) se lec ted

to

AUTO

(4) Manual Mode: None.

[Air

flow

may

be on AUTO].

B)

(1)

O P E R A T O R A C T I O N

Pre -se lec t

r equ i r ed

sub loops to AUTO

Procedure].

[Refer to r e levan t Operating

(2) Select Group Operation

Display

001 [ UNIT MSTR ]

and

ENABLE a l l

subwindows.

(3) Select

the

requi r ed mode. The subwindow disp lays the se lec ted mode. I f

the required permiss ives a re not complete, PERMISSIVE LOSS will be

indicated. Any

f au l ty t r ansmi t te r a f f ec ting

the

Unit Master

o r Fue l /Air

Deviat ion condi t ion

will force the

Unit Master to

remain

in Manual Mode.

(4) After about 5 seconds the mode se lec t ion subwindow ind ica tes the mode

ac t ive condit ion.

I f

the system remains in t he

mode

se lec ted s t a tu s it

means t h a t one of the sub loops i s not cor rec t ly

in i t i a l i zed

[balanced].

This

can

be

caused

by

excess ive

a i r flow,

signi f icant

change

in

fue l

heat ing value or f au l ty

t r ansmi t te r

ca l ibra t ion.


3/32

-2 -

5) The Pressure

Set Point

in i t i l i zes

a t

the ex i s t ing pr e s su r e . Th e

pressure may be s e t to the des i r ed value a f t e r auto

opera t ion

achieved

.

Alternat ively

se lec t

s l id ing

pressure

by se lec t ing AUTO on the

pressure s e t poin t subwindow. Sliding pressure i s

avai lable in

Coordinated

Mode

or Boiler

Follow Mode

with Governor AUTO.

6) The

Targe t

Load

Set Poin t

in i t i a l izes

a t

the exis t ing MW for CO

and

BF

Modes and a t

Fuel

Flow

for BI Mode.

Set

the des i r ed MW load

a t the

Target Load Set Poin t

Subwindow.

7)

Set

the

Minimum

and Maximum

Load

a t

the appropr ia te

subwindows.

This

f ci l i ty

i s mainly

to

l imit t he

load

range

under

Automatic Dispatch

System [ADS] control .

The se t t ing

i s

determined by the number of

burner s in service and any other opera t iona l cons t r a in t s .

8) Set

the r equ i r ed

load

change

r a t e

in MW/MIN a t the Rate subwindow.

Then

se lec t

AUTO a t th i s

subwindow

to permit the

load

change to s ta r t .

9) f ADS control of the

Target Load

i s requi red se lec t AUTO on the

Targe t

Load

subwindow.

ADS

control

i s

avai lable in the CO

Mode only.

C)

C O M M E N T S

1) The maximum load is

l imited

by the auxi l ia ry plant

capaci ty.

[PID:

COAW408]

This i s

calcu la ted from

the

number of

Fans

Feedpumps

Condensate Pumps and oiler

Circu la t ing Water

Pumps in

se rv ice

as

follows:

Each

FD

Fan

360

MW

Each ID

Fan

360 MW

Each MDBFP 90 MW

Each TDBFP 360

MW

Each Cond

Pump 350

MW

Two BCWP 360

MW

Three BCWP

600 MW

The lowest value from the

four

auxi l ia ry

groups

is selected ; for

example one TDBFP and one

MDBFP

would

l imit the t a rge t load to 450

MW

.

The maximum

value

of Auxi l iary

Plant Capacity [APC] i s 635 MW

2)

The

Required

Output

[COAY400]

i s

calcu la ted

from

the

Target

Load

Rate

Se t t e r , Minimum

and

Maximum Limits .

and the

Auxil iary

Plant

Capacity.

The

Required Output

[RO]

i s the se t

poin t

for

Governor Fuel

and

Air

control loops.

3)

f

an

auxi l ia ry t r i p causes the

APC

to

drop

below the ex i s t ing RO

a

RUNBACK

is in i t ia ted. This causes

the

RO to

decrease

as a f a s t r a t e

to

the new value determined by

the

APC. The Unit Master is

automat ical ly

t r ansfe r red

to BI

Mode before

the Runback s ta r t s .

4) The major flow loops a re checked for abnormal devia t ion from t ~

required

value.

This appl ies to

Fuel Air

Governor

Feedwater and

Condensate.

f the aux i l i a ry p lan t

is unable

to

fol low

the

load demand

for

any reason

a

flow

devia t ion

occurs . For

example

fuel

valve

a t

maximum

causes

a

fuel flow low

condi t ion.

Any increase

in

RO is

blocked

and

af te r

a shor t

t ime

delay

the

RO is reduced

unt i l the

devia t ion is

within l imits .


4/32

- 3 -

5) Modes:

MANUAL The t a rge t

load

and requi red

output

t r acks fuel

flow.

The

Air Flow and Oxygen controls may be

placed

on

AUTO The

Air

Demand follows Fuel

Flow

when

above the minimum air flow limit Manual

Mode

s

normally

used

a t

uni t

s t a r t

up

unt i l

s t ab le f i r ing

condit ions

a re achieved.

BASE INPUT The boi ler energy

i npu t [fuel

and air] s se t by the

Target Load. The

re su l t ing MW depends

on the fuel

hea t ing value.

Pressure i s control led to a

f ixed

se t point

i f

the Governor s on

AUTO

[Turbine

Follow]. f the governor i s not auto the

pressure

is

propor t ional to f i r ing r a t e and inverse ly propor t ional to governor

posit ion. Changes in governor posi t ion causes

t rans ien t

change to

MW

Base Input

Mode

s used

when stable boi le r

operat ion s

required.

BOILER FOLLOW The boi ler input i s determined

by

the turbine energy

demand. This s calcu la ted

from

Fi rs t

Stage

Pressure Throt t le

Pressure

and Pressure Set

Point.

Pressure cor rec t ion s

made by

adjus t ing t

boi ler inputs [fuel and air] .

The

governor may

be

on automatic c

manual opera t ion . I f the

governor s on

AUTO i t

controls

MW a t t he

Target Load se t t ing [para 2)]

and

sl id ing

pressure

s

permitted. The

Boiler

Follow

Mode

allows r espons ive

control when the

governor

i s

not

avai lab le

for automatic operat ion.

COORDINATED The boi ler inputs

[fuel

and air] and the governor

respond to a common demand s igna l Required Output. Refer to

Paragraph 2). Sliding pressure and

ADS

control s avai lab le in th is

mode.

The governor is adjus ted

to

cont rol MW and the boi le r

inpu t s

are

regula ted to

maintain pressure . The Coordinated Mode s the

normal

method

of

opera t ion .


5/32

B A N G

P A K O N G 3 4 D C I S

O P E R A T I N G

M O D U L A T I N G

P R O C E D U R E

C O N T R O L S

2

C O M B U S T I O N

A I R F L O W

AIRFLOW.INS 030992

--------------------------------------------------------------------

SYSTEM

COMBUSTION AIR

CONT VARIABLE

TOTAL COMBUSTION AIR FLOW

PID

: SGBF409

CONTROL DEVICE

FD FAN BLADE

PITCH

ANGLE

3SGB-CDR-1,2

SET VALUE

CALCULATED

BY BOILER

MASTER

GSM

PB

COMB AIR

GROUP

DISPLAY

002

COMBUSTION

AIR

TX DEVN

DISPLAY

089

MASTER & AIR XMTRS

A ) P E R M I S S I V E S :

(1)

Fan

se l ec t ed fo r au to operat ion

ON

[ running) .

(2)

Pi tch con t r o l

o l pr e s s u r e 28 Bar.

(3}

No Fuel /Air

Transmit te r

devia t ion .

(4) One o r both ID fan damper AUTO.

B) O P E R A T O R A C T I O N :

(1) Selec t group opera t ion

d isp lay

002 [GSM

COMB

AIR ) and ENABLE t he

subwindows

for

FD fans blade

pi tch .

(2) Check t ha t t he

ind ica ted

Air

Demand

[SV]

i s

a reasonable va lue for t he

ex i s t ing

load condi t ion . [e.g.

for 300MW, should be

approximate ly

50%.

The

minimum

i s

33%]

The

PV and SV

i nd ica t ions

on

Fan

lA

subwindow

should be al igned, ind ica t ing t racking ' balance .

(3) Set b ias se t t ing on Fan lA to ze ro

[cen t re-scale) .

(4) Selec t AUTO for

f ans in

se rv ice .

(5) Adjus t b ia s s e t t e r i f required .


6/32

-2 -

C) C O M M E N T S :

1) The

bas ic

Air

Demand equals

t he

Required

Output [RO]

calcula ted by

the

Boiler Master . When the Boiler Master

i s

n MAN mode the RO equals

Fuel Flow.

(2) The

excess

a i r s

calcula ted

from the .

RO

and the

02 se t

point . The

excess

a i r component

s added

to the bas ic [s tochiometric] a i r demand.

Refer to

02

control notes.

(3) Air flow

control should be

se lec ted

to au to before l ight-of f ;

th i s

ensures tha t the

flow

i s mainta ined above the minimum a i r flow required

for purge. [The minimum a i r flow

i s

se t a t

33 ECR

flow.]

(4)

Boiler Trip

[MFT]

t r i p s

a i r

flow to manual. I t

may

be r e s e t

a f t e r

one

minute.

(5) After

se lec t ing Air Auto

AUTO wil l

be indica ted

on t he subwindow

i t

permiss ives

a re OK The

MAN indica t ion

will remain

on

unt i l

boile

·

master permiss ives

and

in i t i a l iza t ion check i s

complete

[WAITING]. This

takes about 5 seconds. f

MAN remains

on

a i r

flow

may be excess ive

for

f i r ing ra te , or boi le r master permiss ives not

complete

o r ID fan

damper

Not

Auto

.

f a i r flow i s excess ive t he

PV

and

SV

arrows

on

Fan

lA

subwindow

will not al ign and the f lue gas

02

indica t ion will be

higher than the se t poin t

.

Reduce a i r flow unt i l t racking

balance

s

achieved.

(6) Pi tch o l

pressure low

[


7/32

B A N G

P A K O N G

3/4

M O D U L A T I N G

C O N T R O L S

O P E R A T I N G

P R O C E D U R E

3

F L U E G A S O X Y G E N

&

C A R B O N M O N O X I D E

02ANDCO.INS 030992

--------------------------------------------------------------------

SYSTEM

COMBUSTION AIR

CONl' VARIABLE

FLUE GAS 02

&

CO CONCENTRATION

CONTROL DEVICE

EXCESS AIR DEMAND

SET VALUE

CALCULATED BY AIR FLOW CONTROL

GSM

PB

COMB AIR

GROUP

DISPLAY

002

COMBUSTION

AIR

TX DEVN DISPLAY

089

MASTER

& AIR

XMTRS

A)

P E R M I S S I V E S

Flue

Gas

02

(1) No

02

t r ansmi t te r

devia t ion . [Monitor

ON.]

(2)

Air

Flow

Contol

se lec ted

to

AUTO.

(3)

Air

Flow

grea te r

t han minimum f low [33% ECR].

Flue Gas

co

(1) No CO t r ansmi t te r devia t ion .

[Monitor

ON.]

(2) 02 cont ro l

AUTO.

B)


Flue

Gas

02

(1) Check 02 t r ansmi t te r s [4] for reasonable value . [Display 089]. f l l

OK,

se lec t Transmit te r

1

for Eas t

and West s ide s with monitor ON.

(2) Select

group

opera t ion

d i sp lay 002

[Combustion Air] and ENABLE

subwindows

3

and

4.

With

CO cont ro l

in MAN, s e t

output

[MV]

of

CO

subwindow

to

zero. [Centre-scale . ]

(3) Check

02

s e t

value

on

subwindow

3 SV. This i s calcu la ted from

boi le r

load.

I f

a di f fe ren t

value

is requi red

manual ly

ad jus t CO con t ro l

ou tpu t MV [subwindow 4] to ob ta in t he

des i r ed

s e t value

on the

Z

cont ro l subwindow SV. The range of adjus tment is l imited to / 2 02.

(4) Select AUTO

on

02

subwindow.


8/32

-2 -

Flue Gas CO

1) Check

CO

t ransmit te rs

for

reasonable

value . [Display 089]. f both OK

se lec t t ransmit te r 1 with monitor ON.

2)

Selec t

group

opera t ion display

002

[Combustion

Air}

and enable

subwindow

4.

Adjust

t he

se t value SV to t he r equ i r ed value.

3)

Select

AUTO on CO

subwindow .

C ) C O M M E N T S

1) Manual adjus tment of

excess a i r

s

made

from t he

02

subwindow MV

in

MAN mode.

The

02

MV can only

be ad jus ted

when

combustion a i r control

[FD

fans] s

in

AUTO mode.

2)

When 02 cont ro l

i s

suspended

because

t he i r flow i s

a t m ~ n ~ m u m

both

AUTO

and

MAN indica t ions show

on

the

02

subwindow [WAITING].

3) The

rea l time

t r end

for a i r flow fuel flow 02 and CO

should

be checked

f requent ly for normal

combustion condi t ions.


9/32

B A N G P A K O N G

3 4

D C I S

M O D U L A T I N G C O N T R O L S

O P E R A T I N G P R O C E D U R E

4

G A S

F U E L F L O W

GASFUEL.INS 030992

SYSTEM GAS FUEL

CONT

VARIABLE

GAS

FUEL

FLOW

FGAF408

CONTROL DEVICE CONTROL VALVES

3FGA-ACV-l ,

SET VALUE

CALCULATED BY BOILER MASTER

GSM PB FUEL

GROUP DISPLAY

004 FUEL

TX

DEVN

DISPLAY

090

FUEL

FLOW XMTRS

A )

P E R M I S S I V E S :

(1)

Any burner l eve l se lec ted fo r GAS f i r i ng

(2) Tr ip Valve open; header

p ressu re

>

0.11

Bar.

(3)

No Fue l /A i r

t ransmi t te r

dev ia t ion

4) No Heat Release/Metered

Fue l

Flow deviat ion

(5) Fue l /A i r Rat io normal.

(6) M.F.T. reset

(7) Combust ion

Ai r selected

to

AUTO.

(8) Boi le r Master

Mode

selected [CO, BF

o r BI] .


10/32


11/32

B A N G P A K O N G

3 4

D C I S

M O D U L A T I N G

C O N T R O L S


O I L

F U E L

F L O W

OILFUEL.INS 030992

SYSTEM

OIL FUEL

CONT

VARIABLE OIL FUEL

FLOW

FOBF407

CONTROL DEVICE

CONTROL

VALVES

3FOB-ACV-7,8

SET

VALUE CALCULATED BY BOILER MASTER

GSM PB

FUEL

GROUP

DISPLAY

004

FUEL

TX

DEVN DISPLAY

090 FUEL FLOW XMTRS


1) Any burner l e ve l selected

f o r

o l f i r i ng

2) Tr ip Valve open; header

p ressu re

> 6.5 Bar.

3)

No

Fue l /A i r

t ransmi t te r

dev ia t ion

4) No Heat Release/Metered Fuel

Flow

dev ia t ion

5) Fuel /A i r Rat io normal.

6) M.F.T. reset

7)

Combust ion Ai r selected to AUTO.

8) Boi le r Master

Mode

selected [CO,

BF o r BI] .


12/32l..

2

B : : l

O P E R A T O R

A C T I O N

[OIL

O N L Y

FIRING]

(1)

Select

Group Operat ion Display 004 (FUEL) and ENABLE

subwindow

of

the

fuel o l control

valve requi red for auto operat ion . [Only

ONE

valve

of

pa i r

ACV-7/ACV-8

permit ted on

auto a t same

time; each

valve s

>100

capaci ty] .

(2)

Check fuel flow

PV

s

reasonable

value for the exis t ing load condition.

Note

tha t

SV t r acks fuel .

(3) Select

AUTO for

t he

r equ i r ed valve.

(4)

Note AUTO indica t ion

on;

a t th i s

s t age

MANUAL indica t ion also

on.

[WAITING]

If

no

AUTO, check

permiss ives

A)

and t rack ing .

(5)

Select

BOILER MASTER Group Operat ion Display 001.

(6) Select

Governor

mode

[Auto/Manual],

Coordinated Control

mode

[BI,

BF

or

CO]

and Pressure mode [Sl iding/Fixed].

{Refer

to

separa te

procedure f

Boiler Master.}

(7) After

in i t i a l iza t ion and balance

check

[5

seconds] , the

se lec ted boi le r

master

mode

becomes

ac t ive

and t he fuel ,

(as well

as a i r and governor)

go to Auto Mode. The

subwindow MANUAL ind ica t ion s now off.

B2

C O M B I N E D F I R I N G

(1) Refer

to

Fuel Gas Operat ing Procedure for permiss ives for Gas f i r ing.

(2) If

AUTO opera t ion

of gas

fuel required,

se l ec t requi red

gas

valve to

AUTO.

(3) Set

Oil Ratio

Set te r

to

requi red

percentage

o l

flow.

[The Oil

Ratio

Set te r t r acks

the

percentage o l

fuel

i f BOTH fuels a re NOT

auto.]


(1)

Oil fuel

flow

control

funct ions

between burner

header

p res su re

l imits

7.5

to

21.0

Bar.

I f

a

l imit

s

reached,

the fuel

o l

flow

control

t rans fe rs to pressure

control .

An

.

alarm

i s

in i t i a ted to advise Oil

Limited condit ion

exis ts . If

gas

i s

on auto,

the oi l er ro r s

t rans fer red to

the

gas control .

(2)

Each o l fuel control valve i s

>100

capac i ty and

only

one can be on

AUTO

a t one

time. If

opera t ing

condi t ions requ i re the second valve

to

be

opened

i t

must

be under

manual

control .


13/32 .

BANG PAKONG

3 4

MODULAT ING

CONTROLS

O P ERAT I NG

PROCEDURE

6 GOVERNOR

POSITION

GOVERNOR.INS

030992

--------------------------------------------------------------------

SYST M

TURBINE GOVER'NOR

CONT VARIABLE

GOVERNOR

VALVE

POSITION

CONTROL

DEVICE

DEH GOVERNOR

LOAD

SETTER

SET VALUE

CALCULATED BY UNIT MASTER

GSM PB

UNIT MSTR

GRP OPN DISPLAY 001

UNIT

MASTER

TX

DEVN DISPLAY 089

MASTER

AIR

XMTRS

A)

P E RM IS S IV E S

(1) DEH Auto Permiss ive ON [MHI]

(2) DEH IMP Contro l OFF [MHI]

(3) No

t ransmi t te r

deviat ion:

F i rs t

Stage

Pressure [P1]

Thro t t le Pressure

[Pt]

Megawatt

(4) MW/P1 comparison agree.

{5) Uni t Master Mode Selected : [CO, BF o r BI].

B)

OPERATOR ACT I ON

(1) Select Fuel

and

Ai r AUTO [ r e fe r

re levan t

Operat ing Procedure] .

(2)

Select

Group

Operat ion Disp lay 001 (UNIT

MSTR) and ENABLE Subwindow 7,

Governor

Posi t ion

Demand .

(3)

Check PV and

SV [Governor

Demand] are t rack ing and

a t reasonable

value

fo r ex is t i ng load. [e.g. a t 300MW,

PV

= 50 )

(5) Select Governor AUTO.

-

(6) Note AUTO

i nd i ca t ion ON; a t t h i s

stage MAN i nd ica t ion is

a lso

ON

[WAITING].

If no AUTO,

check

permissives and t rack ing .


14/32

-2 -

7) Select requi red Unit Master

Mode.

[Refer

Procedure

1)

{Note: f

Boiler

Follow or Base Input Mode already operat ing , the

Governor may be se lec ted to AUTO a t any time

without re se lec ting the

opera t ing

mode.}

8)

After

in i t i a l iza t ion

and

balance

check,

[5

seconds)

t he se lec ted

Unit

Master mode becomes ac t ive and the governor as

well as

a i r and

fuel)

go

to

Auto Mode. The

Governor

subwindow

MANUAL indica t ion

goes OFF

when

the

DEH accepts

AUTO condit ion from the DCIS. f t he DEH does

not

accept

AUTO

t he

Unit

Master

governor control r e j ec t s

to

MAN. [Refer

to

DEH Operat ing

Ins t ruct ion.

C)

C O M M E N T S

1) In BF

and

CO

Modes,

the governor controls the W

output

to the

value

se t

a t

t he Target

Load

subwindow. In BI Mode, the governor cont ro l s

pressure to the

value

s e t a t the

Pr e s su r e

Set Poin t

subwindow.

2)

Governor

INCREASE i s blocked when

DEH on

Load Limit ON

or

Pressure

is

LOW.

Governor

DECREASE

is

blocked when Pressure

s

HIGH. Refer

also

to

Required

Output

block condit ions, Ins t ruc t ion 1 [Unit Master] Section

C-4.

3)

MANUAL

cont ro l

of governor

va lves i s NOT avai lable from the Unit Master

Governor

subwindow.

MANUAL

CONTROL OF THE GOVERNOR IS ONLY AVAILABLE FROM THE MHI

DEH

GOVERNOR PANEL.


15/32

B A N G P A K O N G 3 4 D C I S M O D U L A T I N G

C O N T R O L S


7 - F U R N A C E

P R E S S U R E

ID F A N D A M P E R S

IDFDAMP.INS 030992

--------------------------------------------------------------------

SYSTEM

INDUCED DRAFT.

CONT VARIABLE:

FURNACE PRESSURE

PID: SGAP401

CONT DEVICE:

ID FAN

INLET DAMPERS

CDR-127

CDR-128

SET VALUE - )

20

mm

GSM PB

FURN GAS

GROUP

DISPLAY

003

FURNACE

GAS

TX

DEVN DISPLAY 089 MASTER & AIR XMTRS


(1)

Fan

se lec ted

for

Auto

operat ion

ON

[running]

(2) No Furnace Pressure

Transmitter

Deviat ion

[Monitor ON]

B)

O P E R A T O R

A C T I O N

1) Selec t Group Operat ion Display

003.

[Press GSM FURN GAS )

and

ENABLE

subwindows for

ID Fan

dampers.

(2) Check furnace pressure s e t point. [Normally -20

mm

WG].

3)

Set BIAS

adjustment

on Fan

1B subwindow

a t

zero [cent re -sca le ] .

4)

Select

AUTO

for

ID

Fans

in

serv ice .

Note

tha t

the

Blue

AUTO

ind icat ion

i s ON.

(5) Observe

furnace pressure t rend for

s t ab le

operat ion.


16/32

2

c)

COMMENTS

1)

Either

or both

fans may

be

selected for

automatic

control

.

AUTO mode

should

be

selected immediately af te r

fan

s ta r t .

2) A separa te sub-window [003-1] is provided

for

the se t point .

3) ID Fan speed control

i s

normally in AUTO mode. I f MANUAL adjust speed

to produce

about

60-70 damper opening a t

requi red load.

4)

I f the actual

pressure

i s

more

t han

/

25mm from

the s e t point ,

damper

movement which increases the

error magnitude is

blocked. This

appl ies

in MANUAL

and

AUTO

modes.

5)

The control led var iable i s the median value from th ree t ransmit ters .

6)

Display

a

rea l

time

t rend

of

furnace

pressure

a t

l l

t imes and check

frequently for abnormal pat terns .

[PID: SGAP401]. ·


17/32

B A N G P A K O N G 3 4 D C I S

M O D U L A T I N G

C O N T R O L S

O P E R A T I N G

P R O C E D U R E

8

ID

F A N S P E E D

IDSPEED.INS

030992

SYSTEM INDUCED DRAFT

CONT VARIABLE

ID FAN

SPEED

CCES009,CCES010

CONTROL DEVICE ID FAN HYDRAULIC COUPLING 3CCE-FAN-1A,

lB

SET VALUE

C a l c u l a t e d

f rom FD a v e r a g e b l a d e p i t c h

GSM PB

FURN GAS

GROUP

DISPLAY

003 FURNACE GAS

TX DEVN

DISPLAY N/A


(1) Fan

se l ec t ed

for Auto

operat ion

i s

ON

[ running] .

(2) No

Furnace

Pressure Transmit te r Deviat ion [Monitor ON].

(3) Hydraul ic coupl ing

se l ec t ed to

REMOTE.

B)


(1) Selec t

Group

Opera t ion

Display 003

[ FURN GAS ] and ENABLE subwindows

for

ID Fan

hydaul ic

coupl ings .

(2) Adjus t

BIAS se t t ing

on Fan lB

subwindow to

zero [cen tre - sca le ] .

(3) Selec t

UTO

for

ID

Fans

in se rv ice .

(4) Adjus t b ia s se t t i ng i required .


18/32

2

C) COMMENTS

(1) Either or both fans may

be

se lec ted for

automatic control . Control

may

be

selected

to

UTO

immediately

af te r

fan

s ta r t .

(2) I f furnace pressure s more than

/-

25

mm

from the

s e t

point any

speed change

command in

the·

direc t ion which increases the er ro r

magnitude s blocked.

This appl ies

n

M NU L and UTO modes.

(3)

The Process Variable s the average speed demand with time constant to

s imulate

actua l

speed response.

·

Transfer

to UTO

s

bumpless

the

speed

will

slowly go to the calculated

se t

point.

(4) The

m n mum speed

under

auto control s

40 . Do not

opera te a t lower

speeds as ins tabi l i ty

[hunting]

may occur.


19/32 c

B A N G

P A K O N G 3/4 D C I S

O P E R A T I N G

M O D U L A T I N G

P R O C E D U R E

C O N T R O L S

M O T O R

B O I L E R

F E E D P U M P S

MDBFP.INS 030992

--------------------------------------------------------------------

SYSTEM

FEEDWATER [MOTOR DRIVEN PUMPS]

CON

.T VARIABLE

DRUM

LEVEL

CONTROL DEVICE

MDBFP 3A, 3B HYDRAULIC COUPLING SPEED

SET VALUE

0 mm

GSM PB

FEED

WTR

GROUP

DISPLAY

010

FEEDWATER

TX DEVN

DISPLAY

092

CNDS FEEDWATER XMTRS

A)

P E R M I S S I V E S :

(1)

Pump

se lec ted for au to

operat ion ON [Running).

(2) No

t r ansmi t te r

deviat ion:

B)

feedwater flow h i range]

f i r s t

s tage pr e s su r e

drum l eve l [east ,

west]


(1) Select group opera t ion

disp lay

010 [FEED

WTR] and

ENABLE subwindow

of

pumps required

on AUTO.

(2)

Check

drum l eve l s e t point . [Normally 0 mm).

Check

l eve l

ind icat ion

aga ins t

Hydrostep. Check

feedwater

flow PV and SV on

Pump

3A

subwindow

for

t r ack balance and reasonable value

for

ex is t ing load

condi t ion.

(3) Set BIAS se t t ing on

pump

3B

to

zero [cen t re-scale] .

(4) Select AUTO for Motor Pumps in serv ice . [Note: The pump speed demand

will go to the

minimum

value r equ i r ed for

pumping a t

the p reva i l ing

drum pressure .

(5)

Adjust bias

se t t e r

i f

required.


20/32

-2 -


(1) The drum leve l

is normally

the average

of the medians

of the

eas t and

west

sides

The

leve l ind icat ion i s densi ty

compensated

over the range

0 -

220

Bar. A

sepa ra te

subwindow i s

provided

for the drum l eve l se t

point.

(2} The feedwater demand FWAF431 i s t he steam flow

f i rs t

stage pressure}

plus drum leve l correct ion.

When s team

flow i nc reases

or decreases ,

the

feedwater flow

f i r s t goes

n t he oppos i te

direct ion to the steam

flow to

compensate

for

drum

l eve l

swel l / shr ink

effect . The feedwater

demand i s the s e t value (SV}

disp layed on

pump 3A subwindow. The flow

range

i s

0-125 ECR.

(3} The feedwater flow (PV) i s

indicated

on

both

pump subwindows.

The

pump

control le r adjusts pump speed so

t ha t

feedwater flow

always

equals

feedwater demand (SV). The 3B pump subwindow SV i s BIAS, range / 20

speed.

(4) The pump speed range i s 2100-7000

r.p.m.

for 0-100

contro l

outpu t

A minimum pump speed bias s calculated from boiler drum pressure .

This fac tor i s added

to

the

speed demand in

auto mode. When

a

pump i s

se lec ted

to

auto,

the

speed demand

immediately

goes

to the calcu la ted

minimum

value.

At th is

minimum speed

the pump pressure

i s

almost

equal

to the drum pressure and

the

pump can immediately

contr ibute flow.

The

second pump may

be

se lec ted to auto a t any speed; balancing s

automatic and bumpless.

(5) When turbine

dr iven

pumps

a re

a l so

se lec ted to

AUTO, the motor

dr iven

pumps follow the turbine pump

control le r

output . Because of dif fer ing

pump

character is t ics ,

the

percentage

flow

may

not

be

the

same

for

turbine and motor pumps.

(6) f

i t s

necessary

to use

manual control for

drum

level , f i r s t make a

t rend

disp lay

showing drum l eve l (SGFL407}, feedwater flow (FWAF419}

and

steam

flow (TGFP400). When leve l s decreasing, INCREASE the flow; when

leve l

s increasing, DECREASE the

flow.

DO

NOT wait for

leve l

to reach

the

se t point before

reve rs ing the

flow. Try to

est imate the average

flow

for

the

exis t ing load

and work

around

tha t

point .


21/32

B A N G P A K O N G 3/4 D C I S

M O D U L A T I N G

C O N T R O L S


10

T U R B I N E

B O I L E R

F E E D P U M P S

TDBFP.INS

030992

--------------------------------------------------------------------

SYSTEM

FEEDWATER [TURBINE DRIVEN PUMPS]

CONT VARIABLE

DRUM

LEVEL

CONTROL DEVICE

TDBFP 2A, 2B

DEH GOVERNOR SPEED

SETTING

SET VALUE

0 mm

GSM PB

FEED

WTR

GROUP DISPLAY

010

FEEDWATER

TX DEVN DISPLAY

092

CNDS & FEEDWATER XMTRS

A) P E R M I S S I V E S :

(1)

Pump

se lec ted for au to operat ion

ON

[ running] .

(2) No t r ansmi t te r deviat ion:

Feedwater flow h i range]

Fi r s t

s tage

pressure

Drum l eve l [east /west]

(3)

DEH

in

Auto [Remote] mode

(TGFZ541

ON)

B)

O P E R A T O R

A C T I O N

(1) Select group opera t ion disp lay

010

[FEED

WTR] and

ENABLE

subwindow of

pumps required

on AUTO.

(2)

Check drum

l eve l

s e t

point .

[Normally

0

mm].

Check

l eve l

ind icat ion

aga ins t Hydrostep. Check ·

feedwater

flow PV and SV on Pump 2A

subwindow

for

reasonable value for ex is t ing load condit ion.

(3) Set BIAS

se t t ing on

pump

2B

to zero

[cen t re scale] .

(4) Select

AUTO

for Motor Pumps in serv ice . The pump speed demand

MV)

will

go

to the

minimum

value r equ i r ed for

pumping

a t the p reva i l ing

drum

pressure .

(5) Adjust b ias

se t t e r i f

required.


22/322

- 2 -

C ) C O M M E N T S :

(1) The

drum level

i s

normally t he

average of

the medians of the eas t and

west

sides

The

leve l ind ica t ion

is

densi ty

compensated

over

the

range

0 -

220 Bar.

A sepa ra te

subwindow

i s

provided for the

drum

leve l se t

point .

(2) The feedwater demand FWAF431

is the steam

flow

f i rs t s t age pressure)

plus

drum l eve l

cor rec t ion.

When

steam

flow i nc reases

or decreases ,

the

feedwater flow f i r s t goes in

the oppos i te d i r ec t ion to the steam

flow

to

compensate

for

drum l eve l swel l / shr ink effect .

The

feedwater

demand i s the s e t value (SV)

displayed on pump

2A subwindow. The flow

range

is

0-125%ECR.

(3) The feedwater flow (PV) i s

indica ted on both

2A and 2B subwindows. The

pump

cont ro l l e r ad jus t s

pump

speed

so tha t

feedwater flow

always

equals

feedwater

demand

(SV).

The

2B

pump

subwindow

SV

i s

BIAS, rang

/

20% speed.

(4) The

pump

speed range

is

2700-5600

r.p.m. for 0-100 control output

(MV).

A

minimum pump

speed

bias

i s

calcula ted

from

boi le r

drum

pressure .

This fac tor i s added to the

speed demand in

au to mode.

When a

pump i s

se lec ted

to auto, t he speed

demand goes to

t he

calcula ted minimum

value.

At th i s minimum speed the

pump pressure

i s almost equal to the drum

pressure

and

the

pump

can immediately

cont r ibu te flow.

The second

pump may be

se lec ted

to

auto a t any speed;

balancing

i s

automatic

and

bumpless.

(5) A

tu rb ine dr iven

pump

cannot

be

control led

from

the

DCIS

[auto

or

manual]

unless

DEH

AUTO [Remote] s igna l

i s

received. When

a

pump is

NOT DEH

AUTO ,

the

subwindow

outpu t [MV] t racks t he

DEH

in te rna l speed

reference

[FWAS031,

030].

(6)

Motor dr iven pumps may

be opera ted

on AUTO in para l le l

with

the

tu rb ine pumps. Because of dif fer ing charac ter i s t ics , the

percentage

flow may

not

be the

same

for

turbine and motor pumps.

(7)

f

i t

is

necessa ry to

use

manual control for

drum

level , f i r s t make

a

t r end

display

showing drum level

(SGFL407), feedwater flow (FWAF419)

and

steam

flow (TGFP400). When l eve l

i s

decreasing, INCREASE t he flow; when

leve l

is increas ing,

DECREASE

the

flow. DO

NOT

wait for l eve l

to reach

the se t point before reversing the flow. Try to es t imate

t he

average

flow for

the

ex i s t ing load

and

work

around tha t

point .


23/32

B A N G

P A K O N G 3 4

D C I S

O P E R A T I N G

M O D U L A T I N G

P R O C E D U R E

11

D E A E R A T O R

L E V E L

C O N T R O L S

DEALVL.INS

030992

--------------------------------------------------------------------

SYSTEM

CONDENSATE

CONT VARIABLE

DEAERATOR LEVEL

CONTROL DEVICE

CONDENSATE PUMP

SPEED

3FWC-P-1A,

lB, lC

SET VALUE

LEVEL:

70% 2132 mm]; PRESSURE: 5

b a r

GSM PB

DEA & CNDS

GROUP DISPLAY

014

DEA & CONDENSATE

TX DEVN DISPLAY

092

CNDS & FEEDWATER XMTRS


(1) Selec ted Condensate

Pump

ON

(2) No

Condensate Flow t ransmit ter devia t ion

(3) No Deaera tor

Level t ransmit ter devia t ion

B) O P E R A T O R

A C T I O N

(1)

Select group

operat ion d isp lay 014

and

ENABLE subwindow of

pumps

r equ i red

on

AUTO.

(2) Check s e t poin t for

deaera tor

leve l and condensa te

pressure .

(3) Set bias se t t ings to zero [cen t re-scale] .

( 4) Select AUTO for pumps in serv ice .

5)

Adjust bias s e t t e r s i required .

(

C ) C O M M E N T S :

1}

The minimum

speed

demand for au to operat ion i s 30% speed.

(2)

Under

normal condi t ions, t he

condensa te

pr e s su r e will be

gr e a t e r

t han

the

minimum

s e t point . I f the

pressure fa l l s below

the

minimum

pressure , the

l eve l

cont ro l

s suspended

and the pump

speed s

adjus ted to mainta in

the r equ i r ed pressure .

(3) I f deaera to r

l eve l i s

grea te r

t han

90% [2525 mm],

the deae ra tor high

l eve l con t ro l le r opens overf low valves

ACV-170, 173

and dumps t he

excess condensa te to

the

condenser . The high l eve l

control

s always

in

auto mode. [GSM: DEA MISC ]


24/32

B N G

P K O N G

3/4 D C I S

O P E R T I N G

M O D U L T IN G

P R O C E D U R E

12 C O N D E N S E R L E V E L

C O N T R O L S

CONDLVL.INS

030992

--------------------------------------------------------------------

SYSTEM

CON.T

VARIABLE

CONTROL DEVICE

SET VALUE

MAKEUP

SET VALUE DUMP

GSM

PB

GRP OPN

DISPLAY

TX DEVN DISPLAY

CONDENSATE

CONDENSER

LEVEL

NORMAL MAKE UP-VALVE

ACV-54

EMERGENCY

MAKE-UP

VALVE ACV-57

CONDENSATE DUMP VALVE

ACV-63

70

90%

DEA CNDS

014

DEA

CONDENSATE

098

HEATER

LEVEL

XMTRS

A)

P E R M I S S I V E S

(1) No

condenser l eve l

t ransmi t ter

devia t ion [Moni tor

ON].

B)

O P E R T O R

C T I O N

(1)

Check

l eve l

t ransmi t ters fo r reasonable value

[Tx

Disp lay

098].

f both

OK

select

t ransmi t te r 1

and

moni tor ON.

(2)

Select Group

Operat ion

Display

014 [DEA CONDENSATE] and ENABL

Subwindows

6,7,8. [ACV-54, 57, 63]

(3)

Adjust

set po in ts [SV] to requi red value.

(4)

Select

AUTO f o r the three valves

[ACV-54,

57, 63]

C) C O M M E N T S

(1) Under

normal

operat ing

condi t ions,

condensate

losses

wi l l be made

up by

valve

ACV-54. Valves ACV-57 and ACV-63 wi l l be

shut. Emergency

Makeup Valve ACV-57 wi l l open i high water l oss causes ACV-54

to

be

100

open.

(2)

Changes

in

operat ing

condi t ions

can

cause a

t rans ient

i nc rease o f

condenser

l eve l

The

make-up

valves

ACV-57

and

ACV-54

close

as

the

l eve l

approaches the

se t

value. Above the

se t

value, both

make-uo

valves

are closed. f the l eve l is grea te r the dump se t value,

the

dur

valve ACV-63 opens. The opening s propor t i ona l

to

the l v ~ devia t ion


25/32

B A N G P A K O N G 3/4

M O D U L A T I N G

C O N T R O L S


13

S E C O N D A R Y

S U P E R H E A T E R O U T L E T

T E M P E R A T U R E

SECSHO.INS

030992

--------------------------------------------------------------------

SYSTEM

MAIN STEAM

CONT

VARIABLE

SECONDARY SUPERHTR OUTLET TEMPERATURES

2A,2B

CONTROL

DEVICE

1ST STAGE DESH

lA lB lC lD SPRAY CONTROL

VALVES

lC: ACV-357 & ACV-362

lD: ACV-368 & ACV-373

1A: ACV-227 & ACV-232

lB: ACV-319 & ACV-325

SET

VALUE

CALCULATED FROM

BOILER LOAD.

[Refer B(3)]

GSM PB

SSHA SPRAY [TO

STEAM LINE 2A FROM DESH 1C, 1D]

SSHB SPRAY [TO STEAM

LINE

2B

FROM

DESH 1A, 1B]

GROUP DISPLAY

TX DEVN

DISPLAY

006

SEC

SH TO 2A LINE

007 SEC SH TO 2B LINE

094

STEAM TEMP

XMTRS 1

A) P E R M I S S I V E S

(1) No

thermocouple deviat ion [Monitors

ON]

(2) No

f i r s t stage

pressure deviat ion

[Monitor

ON]

(3)

Modulate permit from

BVI

logic ON

(4) No

CLOSE VALVE

command

from

BVI logic

B)

O P E R A T O R

A C T I O N

(1)

Check thermocouples [Display 094] for reasonable

values

and

pair

agreement.

(2)

Select group operation display 006 [GSM: SSHA

SPRAY].

ENABLE

subwindows for

se t

value

and for valves

required

for operation.

(3)

Select AUTO

on

se t point subwindow

[1].

I f manual

se t

point required,

select MAN

and

adjust

se t

value

to the required

temperature.

(4) Select

AUTO

for

DESH

1C,1D

required spraywater valves.

(5)

Select

group

operation display

007

[GSM:

SSHB

SPRAY].

subwindows

for valves required for

operation.

(6)

Select

AUTO

for DESH

1A,1B

required spraywater valves.

ENABLE


26/32

-2 -

C )

C O M M E N T S

(1)

There

are

th ree

sec t ions

of

main steam superhea t ing; PRIMARY

uncontrolled),

SECONDARY

control led by

the

f i r s t stage desuperheaters

lC,lD,1A,lB)

and

TERTIARY [FINAL]

control led by the second s t age

desuperheaters A and

2B).

(2) . The

steam

l ines from each s ide of t he secondary superhea te r ou t l e t

header CROSS OVER before

going

to the second stage desuperheaters A

and

2B. [DESH 1C,1D > 2A; 1A,1B > 2B]

(3) A sepa ra te con t ro l system i s provided for each side

of

the secondary

superheater .

The same

se t

value s used

for

each system.

(4)

Each desuperheater

has

two

100 spray

valves. Only ONE valve can be

AUTO

a t

the

same

time.

(5) The

se t poin t

subwindow

appear s on

group

opera t ion displays

006 ana

007. Either

may be used.

(6) A sepa ra te ins t ruc t ion

s

provided

for t he

t e r t i a ry

superhea te r

out le t

temperature control .


27/327

B A N G P A K O N G

3/4 M O D U L A T I N G C O N T R O L S


14 T E R T I A R Y

F I N A L )

S U P E R H E A T E R

O U T L E T

T E M P E R A T U R E

TERSHO.INS 030992

--------------------------------------------------------------------

SYSTEM

CONT VARIABLE

CONTROL DEVICE

SET

VALUE

GSM PB

GROUP DISPLAY

TX DEVN DISPLAY

MAIN

STEAM

TERTIARY SUPERHTR OUTLET

TEMPS

(WEST,EAST)

2ND STAGE

DESH

2A,2B SPRAY CONTROL VALVES

2A: ACV-215 ACV-220

2B :

ACV-330 ACV-336

CALCULATED

FROM

BOILER

LOAD

[R e fe r

B ( 3 ) ]

TSH

SPRAY

008 TERTIARY

SH

094,095

STEAM

TEMP XMTRS

1, 2

A) P E R M I S S I V E S

1) No

thermocouple

dev ia t ion

[Moni tors

ON].

(2} No f i r s t

stage

pressure dev ia t i on

[Moni tor

ON].

(3} Modulate

permi t

f rom

BVI logic ON

(4}

No CLOSE

VALVE

command

f rom

BVI logic

B)

O P E R A T O R

A C T I O N

(1) Check thermocouples [D isp lay

094,095]

fo r reasonable values and

pa i r

agreement

.

(2)

Select group

opera t i on d isp lay 008 [GSM: TSH SPRAY ]. ENABLE

subwindows

f o r

se t va lue and

fo r va lves

requ i red

f o r

operat ion.

(3)

Select AUTO on

se t

po in t

subwindow

[1]. If manual set po in t requ i red ,

se lec t MAN

and ad jus t

set value to the requ i red temperature [Usual ly

540 deg].

(4)

Select

AUTO fo r DESH 2A,2B requ i red spraywater va lves .


28/32

2

C) C O M M E N T S

(1)

There are

th ree sec t ions of main s team superhea t ing; PRIMARY

uncontrolled),

SECONDARY

control led

by

t he

f i r s t

stage desuperheaters

lC,lD,lA,lB) and

TERTIARY [FINAL] control led

by

the second s t age

desuperheaters

A

and 28).

(2) The steam l ines from

each

side of the

secondary superhea te r

out le t

header

CROSS OVER before oin to the second s t age desuperhea te r s A

and 2B. [DESH lC,lD > 2A; lA,lB > 2B] The second s t age

desuperheaters 2A,

B

control the

t e r t i a ry

superhea te r

out le t

tempera tures

[West,

East].

(3) A separa te cont rol system

s

provided for each side of the

t e r t ia ry

[final] superheater . The

same

s e t value

s

used for each

system.

(4) Each

desuperheater has two

100 spray valves . 0nly ONE valve can

AUTO a t the same

time.

(5) A sepa ra te ins t ruc t ion

s provided for

the secondary superhea te r out le t

temperature control .


29/32

B A N G

P A K O N G

3 4

D C I S M O D U L A T I N G

C O N T R O L S


15 R E H E A T S T E A M T E M P E R A T U R E

[ G A S

R E C I R C U L A T I O N ]

GASRECRCT.INS 030992

SYSTEM

REHEAT

STEAM

CONT

VARIABLE

REHEAT

STEAM

TEMPERATURE

CONTROL DEVICE

GAS

RECIRCULATION

FANS 2A, 2B

CDR-125,

CDR-126

SET VALUE 540 DEG

SM

PB

RE HTR

GROUP

DISPLAY

009 REHEATER

TEMP

TX DEVN DISPLAY

095 STEAM TEMP XMTRS #2


{1) No thermocouple dev ia t ion;

West/East.

2)

No

F i rs t

Stage

Pressure

t ransmi t te r

dev ia t ion

{3) No Boi ler Tr ip

4)

Selected

fan ON [Running].

B)

O P E R A T O R

A C T I O N

{1)

Check

thermocouples

[D isplay

095} f o r reasonable

value

and pa i r

agreement.

{2)

Select Group

Operat ion

Disp lay

009 [ RE HTR ]

and ENABLE subwindows

fo r

Burner T i l t and Gas

Rec i rcu la t ion

Fans.

{3) Adjust BIAS

se t t i ng

on Fan 2B

subwindow

to

zero [ cent re scale] .

{4) Adjust reheat steam

temperature

se t

po i n t

on Fan 2A t o requ i red value

[540 Deg

a t

normal

load].

5) Select AUTO on Burner T i l t subwindow.

6) Select AUTO on

Gas

Reci rcu la t ion Fans

subwindows.

7) Adjust R

Fan

bias

se t te r

i requi red


30/32

-2 -

C )

C O M M E N T S

1)

The

maximum rehea t

steam se t point reduces as boi ler load decreases.

This maximum value

overr ides

the

opera tor

se t point . Refer

function

genera tor FG 78.

2) The

GR

Fan inle t vanes have a minimum posi t ion when in UTO mode. The

minimum var ies with load.

3) . The maximum

in le t

vane

posi t ion

is l imited by motor

current; the

maximum

value

i s

100

Amps. The maximum

current control overr ides

temperature control.

4)

Burner t i l t posi t ion

i s

control led as

a

function

of

boi ler load and

percentage o l fuel.


31/32

B A N G

P A K O N G 3 4

D C I S

M O D U L A T I N G C O N T R O L S

O P E R A T I N G

P R O C E D U R E

16

R E H E A T

S T E A M

T E M P E R A T U R E [ S P R A Y S ]

RHSPRAYS.INS

030992

--------------------------------------------------------------------

SYSTEM

REHEAT

STEAM

\.

CONT VARIABLE

REHEAT STEAM

TEMPERATURE

CONTROL DEVICE REHEAT DESH

3A,

3B

[ACV-241,246,257,262]

SET VALUE 540

DEG

[+5 DEG

when

GR Fan AUTO]

GSM PB

RE HTR

GROUP DISPLAY

009

REHEATER TEMP

TX DEVN DISPLAY

095

STEAM

TEMP

XMTRS

2


(1)

No

thermocouple

deviat ion [Monitor ON]

(2)

Modulate permit

from BVI

Logic ON

(3)

No

CLOSE

command

from

BVI

Logic

B)


(1) Check thermocouples

for

reasonable

value

and

pair

agreement

(2) Select Group Operation Display 009. [Press

GSM

RE HTR ] and

ENABLE

subwindows for

required

control valves.

(3) Check

se t

point

[Gas

Recirculation

Fan

A subwindow]

(4)

Set

BIAS

adjustment

on

RH

spray

bias

subwindow

a t

zero.

(5) Select AUTO

for

requi red

RH spray

valves

(6) Adjust bias

se t t e r if required.


32/32

2

C)

C O M M E N T S

(1) Under

normal

condit ions

the

Reheat

temperature

i s

control led by the

Gas

Recirculation

Fans.

The

s e t

point for

the

rehea t sp ray

valves

control ler

i s 5

deg higher than the GR

fans and

the valves are normally

closed. .

I f

the temperature i s more

than

5 deg above

the

se t point

the

spray

valves

open to provide back-up control. I f the

GR

fans are

manual the 5 deg bias

i s

removed and the sp rays

control

to the se t

point.

2)

Both desuperheaters

3A

and 3B must be selected to AUTO

valve of each pai r can

be

AUTO

Only

ONE

modulating control(operating procedure)

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