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May 24, 2012 PMI Revision 00 1

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Presentation outline

Overview of Plant Controls

Functions of ATRS

Structure of ATRSProgram Structure of ATRS and

Turbine protection

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OPERATOR

INSTRUMENTATION & CONTROL

PLANT

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UNIT CONTROL

BOILER TURBINE GENERATOR

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MEASUREMENT

CLOSE-LOOP

CONTROL

OPEN-LOOP

CONTROL

PROTECTION

MONITORING

INSTRUMENTATION

ANDCONTROL

INSTRUMENTATION

ANDCONTROL

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ADVANTAGES OF AUTOMATION

OPERATING PERSONNEL FREED FROM ROUTINE TASKS.

INCORRECT INTERVENTIONS IN THE PROCESS AVOIDED.

STRESS ON EQUIPMENT REDUCED.

PLANT OPERATIONS GEARED FOR MAXIMUM

EFFICIENCY.

INCIPIENT FAULTS RECOGNISED QUICKLY.

ON FAULT OCCURRENCE, IMMEDIATE AND LOGICAL

INTERVENTION POSSIBLE.

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A. CONTROL SYSTEM:

ANALOG(CLOSE LOOP)

- ELECTROHYDRAULIC CONTROLLER (EHC)- TURBINE STRESS EVALUATOR (TSE)

- LOW PRESSURE BYPASS CONTROLLER (LPBPC)

- GLAND STEAM PRESSURE CONTROLLER (GSPC)

BINARY(OPEN LOOP)

- AUTOMATIC TURBINE RUN UP SYSTEM (ATRS)- AUTOMATIC TURBINE TESTER (ATT)

B. MONITORING & MEASUREMENT SYSTEM

- TURBINE SUPERVISORY INSTRUMENTATION (TSI)

- MEASURMENT OF PARAMETERS LIKE, TEMP.,PRESS.,LEVEL etc.

C. PROTECTION SYSTEM

TURBINE C&I PACKAGE CONSISTS OF THE FOLLOWING SYSTEMS:

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HIERARCHY OF CONTROL

UNIT

CONTROL

GROUP CONTROL(WHEN, HOW MANY,WHICH)

SUB-GROUP CONTRL-1 SUB-GROUP CONTRL-2

CONTROL INTERFACE

SWITCH GEAR (MCC)

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TASKS PERFORMEDTASKS PERFORMED:

SWIFT,ACCURATE AND OPTIMUM STARTUP ( INCLUDING

SYNCHRONISATION AND LOADINING) OF TURBINE

MAINTAINING OIL SUPPLY

BUILDING UP AND MAINTENANCE OF VACUUM

FEATURES :FEATURES : BASED ON FUNCTIONAL GROUP CONTROL PHILOSOPHY

EACH FUNCTIONAL GROUP ORGANISED AND ARRANGED IN SUB-GROUP CONTROL,

SUB-LOOP CONTROL, AND CONTROL INTERFACE

OPERATING MODES AVAILABLE:

- MANUAL MODE ( OPERATOR GUIDE)- AUTOMATIC MODE

- STEP BY STEP MODE

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ATRS

STRUCTUREOIL SYSTEM, VACUUM SYSTEM, TURBINE etc.

GC

SGC SGC

SLC SLCSLC

CI

SGC

CI

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GROUP CONTROL: Decides WHEN, HOW MANY & WHICH SGC

shall be operating and stopped.

SUB GROUP CONTROL: Contains the sequential logics for switching

drives ON and OFF. Perform sequence in STEPS, issue commands and

get Checkbacks.

SUB LOOP CONTROL: can be switched ON & OFF manually.Receive commands from GC, SGC and also Manual

CONTROL INTERFACE: Standard Interface between the command

transmitters and receivers in the plant, undertakes all necessary signal

processing and monitoring.

SYSTEM OPERATION MODES:

AUTOMATIC,SEMI AUTOMATIC,OPERATOR GUIDE

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ADVANTAGES OF ATRSADVANTAGES OF ATRS

ELIMINATES HUMAN ERROR PROVIDES MAXIMUM PROTECTION AGAINST MALFUNCTIONS

OPERATORS TASK LESS ARDUOUS

ENABLES SAFE, SMOOTH, STRESS CONSISTANT AND OPTIMUM

WARM-UP, ROLLING AND SYNCHRONISATION OF TURBINE IN

LEAST POSSIBLE TIME INCREASES PLANT AVAILABILITY

REDUCES STARTING TIME WITHOUT IMPAIRING LIFE

MEETS EMERGENCIES AUTOMATICALLY

ALL PLANT OPERATING CONDITIONS CATERED TO BY CRITERIA

DEPENDANT PROGRAMMING

INCREASED OPERATING FLEXIBILITY, SAFETY AND RELIABILITY

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Start up and Shutdown sequence performed in reliableway

Protect drives and related auxiliaries

Uniform and sequential information to operator aboutthe process

Distinct information about the nature and location offaults

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STEP 01

STEP 02

&

START DRIVE A

DRIVE A ON

MONITOR &

BLOCKING TIME

MONITOR &

BLOCKING TIMEOPEN DMPR A

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AUTOMATIC TURBINE RUN-UP SYSTEM

SUB GROUP CONTROL ( SGC):

SGC executes commands to bring the equipment upto a particular

defined status.

The commands are executed in a predefined sequence in the form of

steps.

Desired number of criteria act as preconditions before the SGC can

take off or execute its defined sequence. The functional group continues to function automatically all the time

demanding enabling criteria based on the process requirements and

from other FGs, if required.

In case the desired criteria is not available, the system would

automatically act in such a manner as to ensure the safety of the mainequipment.

The sequence is programmed in the processor. The process signals

are acquired through the input modules and are available on the bus.

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WAITING AND MONITORING TIME FOR STEPS:WAITING AND MONITORING TIME FOR STEPS:

Waiting Time :

It implies that the subsequent step will not be executed unless the

specified time elapses. If no waiting time is specified, the next step

gets executed as soon as the enabling criteria are fulfilled.

Monitoring Time :

It is the time required for executing the command of any step as well

as the time required for appearance of criteria for the next step.

Under healthy conditions it should happen within the specified time,

otherwise an alarm is initiated. Whenever there is uncertainty

regarding the time required for completing a particular task, such

as warming-up, pulling vacuum etc., the monitoring time is blocked.

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02

FROM STEP 1STEP CRITERIA FOR STEP -2

BYPASS CRITERION

PROGRAM LOOP

WAIT

50s

MO TIME

20sCOMMAND

1

2

&

&

1

&

STEP 2 ( START UP PROGRAM) WITH 2 STEP CRITERIA, 2 COMMAND

OUTPUTS AND A MONITORING & WAITING TIME .

WITH ADDITIONAL PROGRAM LOOP CONTROL AND A BYPASS

CRITERIA FOR STEP 1

WAITING OR MO TIME CAN BE PROGRAMMED FOR 0.1 SEC TO 999

MIN.

NOS. 1-49 USED FOR START-UP, 51 TO 99 FOR SHUTDOWN PROGRAM.

EXAMPLE

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WAITING AND MONITORING TIME FOR STEPS:

ATRS can be switched on at any stage after

completing certain tasks manually, if so desired. In

such cases, the SGC program quickly scans throughthe steps and starts executing from the stage upto

which the tasks have been completed manually.

This is achieved by incorporating suitable

overflow /bypass conditions in the logic.

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ATRS CONTROLS:11. ATRS is organised in the following four Sub-Groups :

Oil supply

Evacuation

Turbine

HP CONTROLFLUID

2. SGC issues commands either to the SLC or directly to

the drive through the Control Interface.

3. Each of these SGCs has its subordinate SLCs and CI

modules. These SGCs in conjunction with the turbinegoverning system , TSE and the auto-synchroniseraccomplish the function of start-up of the TG set.

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CONTROL INTERFACE (CI) :

Each remote controlled drive has a dedicated CI module which acts asa standard interface between the transmitters and receivers in the plant

and undertakes all necessary signal processing and monitoring.

The CI module receives manual commands from the process

keyboard/inserts, active protection signals and enabling signals from

the protective logic, as well as automatic control commands from the

SGC/SLC. It interlocks the input commands according to their priority and

validity and then passes actuation signals to the interposing relays in

the switch-gear.

The status checkbacks received from the switchgear or actuators are

monitored, processed and transmitted to VDU/desk tiles, the protective

logic and the SGC.

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CONTROL INTERFACE (CI) : (Continue--)

These modules have the firmware which defines the standard

function of the module and its signalisation mode as well as the

programmable logic for the drive protection and the permissive

interlocks. The drive level automation tasks related to the respective

drive is realised through the programmable logic.

The module has hardwired inputs and outputs for connection of

feedback signals and commands to the switchgear together with local

bus interface for signal exchange via the system bus.

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ATRS STRUCTURAL SYSTEMATRS STRUCTURAL SYSTEM::

ATRS IS ORGANISED IN THREE SGCs :

1. SGC-TURBINE :

SGC Turbine acts directly on the following systems :SGC Turbine acts directly on the following systems :

Sub-loop Control (SLC) Drains.

Warm up Controller.

Starting Device of turbine governing system.

Speed & Load Setpoint devices of turbinegoverning

system.

Auto-synchroniser.

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2. SGC-OIL SUPPLY :

SGC oil supply directly acts on the following systemSGC oil supply directly acts on the following system :

Sub-loop control (SLC) turning gear.

SLC auxiliary oil pump 1.

SLC auxiliary oil pump 2.

SLC emergency oil pump. SLC jacking oil pump.

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3. SGC-CONDENSATE & EVACUATION :

SGC- Condensate & Evacuation directly acts on the following systems :

Sub-loop Control (SLC) condensate extraction

pumps.

Starting ejector, if provided.

Main ejectors / vacuum pumps (as applicable). Vacuum breaker.

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3. SGC-HPCF :

SGC- HPCF acts on the foll :

Sub-loop Control (SLC) HPCF

SLC HPCF pumps

HPCF pumps

HPCF re-circulation pumps LPCF temp control valve

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3. SGC-HPCF :

Both CF PUMPS GET SWITCHED ONTHRU SLC. IN CASE

RUNNING PUMP DOES NOT DEVELOP THE REQUIREDPRESS, THE STANDBY PUMP GETS SWITCHED ON

AFTER GETTING THE REQUIRED CF PRESS SLC

HEATING IS PUT ON & CF CIRCULATION PUMP WHICH

FEEDS THE REGENERATION CKT IS ALSO PUT ON. TEMP

CONTOL VLV IS PUT IN AUTO MODE TO REGULATE THETEMP.

CF TEMP IN THE TANK IS MAINTAINED BETWEEN 55 TO

57 C BY SWITCHING ON/OFF THE CF HEATER THRU

THE SLC. IN CASE CF TEMP IN HTR EXCEEDS > 65 C

THE HEATER IS SWITCHED OFF IN SHUTDOWN PROG ALL THE PUMPS ARE SWITCHED

OFF AND SLC IS PUT OFF. SLC HEATING IS KEPT ON TO

MAINTAIN THE TEMP REQUIRED FOR THE NEXT

STARTUP.

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TURBINE START-UP / SHUT-DOWN CONTROL,

OVERVIEW

SUB-GROUP ( TURBINE START-UP / SHUT-DOWN)SUB-GROUP ( TURBINE START-UP / SHUT-DOWN)

SUBLOOP

DRAIN

VALVE

SUBLOOP

LP-WATER

INJECTION

MECHANICAL

HYDRAULIC

CONTROL(MHC)

ELECTRO-

HYDRAULIC

CONTROL(EHC)

SEAL

STEAM

CONTROL(SSC)

TURBINE

TRIP

SYSTEM(TTS)

TURBINE

STRESS

EVALUATOR

LP WATER

INJECTION

AUTOMATIC

SYNCHRONIZER

DRAIN

VALVES

GENERATOR

MAIN CKT.

BREAKER

THYRISTOR

VOLTAGE

REGULATOR(TVR)

CRITERIA

CRITERIA

AUTO-ON/OFF

AUTO

ON/OFF

AUTOON/OFF

MANUAL

ON/OFF

MANUALON/OFF

MANUALOPEN/CLOSE

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4 6 8 7 5

1

3

2

1. PUSHBUTTON SHUTDOWN

2.PUSHBUTTON STARTUP OR OPERATION

3.PUSHBUTTON AUTOMATIC ON/OFF

4.LAMP SHUTDOWN PROGRAM5.LAMP STARTUP OR OPERATION PROGRAM

6.LAMP AUTOMATIC OFF

7.LAMP AUTOMATIC ON

8.LAMP FAULT

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2 3 4

1. PUSHBUTTON MANUAL ON/OFF

2.LAMP SLC OFF

3.LAMP FAULT

4.LAMP SLC ON

1

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3 4 5

1. PUSHBUTTON OFF (CLOSE)

2. PUSHBUTTON ON (OPEN)

3. LAMP OFF (CLOSE)

4. LAMP FAULT

5. LAMP ON (OPEN)

1 2

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PROTECTION SYSTEMFOR

STEAM TURBINE

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TURBINE PROTECTION SYSTEM

TASK PERFORMEDTASK PERFORMED :

PROTECTS TURBOSET FROM INADMISSIBLE OPERATING

CONDITIONS

PREVENTS DAMAGE IN CASE OF PLANT FAILURE

FAILURE OCCURRENCE REDUCED TO MINIMUM

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ADVANTAGESADVANTAGES :

DETECTION OF UNIT IRREGULARITIES

PREVENTION OF UNIT OVERSTRESSING DUE TO TRIPS

RELIEF OF OPERATING PERSONNEL FROM QUICK AND

CORRECT DECISION TAKING

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TURBINE PROTECTION SYSTEMTURBINE PROTECTION SYSTEM

HYDRAULIC

TRIP SYSTEM

ELECTRICAL

TRIP SYSTEM

EXTENDED

TURBINE PROT.

PROT. CRITERIA

FROM OTHER AREA

- OVER SPEED

TRIP DEVICE1/2

- VACUUM TRIPDEVICE

- HAND TRIPLEVER(LOCAL)

1/2

- MANUAL

REMOTE TRIP( UCB)

- LOW VACUUM

TRIP

- LOW LUBE OIL

- FIRE PROT.

TRIP-BRG METAL

TEMP

-AXIAL SHIFT

-HP/IP TOP/BOT

DIFF TEMP HI

- LP EXH. STM.

TEMP. > MAX

-GENERATOR

PROTECTION

- MASTER FUEL

TRIP RELAY

ENERGISED

- BOILERPROTECTION

OPTD.

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GENERALGENERAL :

The electrical trip system comprises of two identical and independent

relay based trip channels viz. electrical trip channels 1 & 2.

Both channels are connected to different (two) trip solenoid valves.

All command signals for turbine trip are hooked up with both the

channels.

Actuation of any of the channels energises the respective trip solenoid

which in turn trips the turbine.

Each channel is realized in a local bus. Both the local buses are

completely independent of each other and input modules, processor

module and output modules reside on each.

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GENERALGENERAL :

Trip signals from the sensors / field instruments are conditioned anddistributed to both the channels (local buses) via hardwired modules.

Realisation of 2 out of 3 trip logic is carried out in the local bus. On

detection of a fault in any one of the input signals to a channel, the

configuration for that channel changes from 2 out of 3 to 1 out of 2 and is

annunciated. Further failure in a channel changes the configuration to 1out of 1.

Trip signal from each of the local buses acts on 3 relays in 2 out of 3

combination.

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TRIPPING CRITERIATRIPPING CRITERIA:

1. CONDENSER VACUUM VERY LOW :

This is a back up protection to the hydraulic low vacuum trip

device.

The protection acts if absolute pressure in the condenser rises

above 0.3 Kg/cm2 (abs).

2. LUBE OIL PRESSURE LOW :

The protection acts if the lube oil pressure before thrust bearing

decreases to 1.2Kg/cm2 . The trip signal is initiated by three pressure transmitters in 2-out-of-3-

logic.

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3. FIRE PROTECTION :

The protection acts in the event of any of the following

conditions :

i) Fire protection switch, either in unit control room

or in

machine hall, operated.

ii) Level in main oil tank falls to a very low value,

indicating

substantial leakage of oil from the system.

The command signal under condition (ii) is initiated from

three level transmitters in 2-out-of-3 logic cofiguration.

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4. HP EXHAUST STEAM TEMPERATURE HIGH :

The HP exhaust steam temperature protection circuit causes the exhaust

sections of the turbine, the blading and the extraction points against

overheating. Under extreme operating conditions the HP turbine can be run at low flow rate

and simultaneous relatively high back pressure. This prevents the steam from

expanding, which causes the exhaust steam temperature to rise ( > 5000C).

The temperature is measured by means of three thermocouples and protection

criteria is derived in 2 out of 3 logic.

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7. GEN. PROTECTION OR MFT- RELAY ENERGISED :

In the event of generator faults under Class-B trip both the turbine trip

channels are actuated to trip the turbine. In such a case the generator

protection acts through Reverse Power Relays.

In the event of generator faults under Class-A trip or in the event of boiler

"Master fuel trip relay" energised, command signal for turbine trip shall

act simultaneously and independent of other equipment trip out sequence.

8. OPERATION OF REVERSE POWER RELAY :

The command signal is initiated with a time delay of 10 seconds after any of

the two reverse power relays have operated.

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