TURBINE CONTROL LOGIC FOR “MAIN TURBINE(TD-0301)”

IN EPRU

By

V R N V PRASAD RAIDU CH

Topics

EPRU PLANT

TURBINE TD-0301

WOODWARD SYSTEM DESCRIPTION

CONTROL SCHEMES

TURBINE PROTECTION SYSTEM

WOODWARD SYSTEM HARDWARE DETAILS

Residue gas

compression

Inlet gas

compressionAminetreating

Amine Regeneration

MSDehydration

Cryogenicplant

C2 C3storage

Propylene Refrigeration

MSRegeneration

Inlet gas

Lean gas

EPRU PLANT

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TURBINE TD-0301

Manufacture : Siemens

Performance Details: Shaft:

Power: 21431 kWSpeed: 8932 Rpm

Inlet

Extraction 1

Extraction 2

Exhaust

Flow Pressure Temperature

149.9 T/Hr

18.83 T/Hr

74.57 T/Hr

104 kg/cm2

42.5 kg/cm2

3.5 kg/cm2

0.16 kg/cm2

490oC

370oC

150oC

57.1oC

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Woodward Micronet TMR control system

Used for

Turbine controlTuning gear controlTurbine trip signal generation

HMI systemOverview of pictures of the turbineAllows for alarm annunciationMonitoringTrendingManual operation

Serial communicationCPU-A : RS-232 communication for Citect systemCPU-B : RS-232 communication for DCS systemCPU-C: Woodward service tools

Control software moduleGAP

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Control schemes

1. Condenser pump logic scheme

2. Ratio limiter logic

3. IP/LP extraction enable logic

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Logic:

1. If the selection switch on LCP is selected for ‘Manual’ then pumps can be started and stopped from LCP

PB’s or from MMI PC in CR. Logic scheme does not come in line.

2. If selection switch on LCP is selected for ‘Auto’ then following logic scheme will be effective. One more

selection switch on LCP is provided for preference selection between pump 1 and pump 2.

When selection switch on LCP is changed over from ‘Manual’ to ‘Auto’ position, running pump/pumps

will stop. On LAH, selected pump will start automatically. On LAH preference selected pump will start automatically. The preference selected pump will remain in

running condition even after LAH reset(i.e. normal level) If under normal condition preference selected pump is running, then on LAH other pump will not start

automatically. However if electric fault feedback is received from MCC for preference selected (existing

running) pump then on LAH other pump will start automatically. ON LAHH both pumps will start automatically. If LAHH does not reset within 45 seconds then turbine

will trip. ON LALL both the pumps will trip. Both the pumps will remain in stop condition till LAH. ON LAH

preference selected pump will start automatically.

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RATIOLIMITER

Speed controllersignal

Extractioncontroller 1signal

Extractioncontroller 2signal

HP driver signal ( % )

IP driver signal ( % )

LP driver signal ( % )

SC

PCE1

PCE2

1. HP governor valve opening:

= 0.641*{(SC.PID+61.6)+((PCE1.PID-100)*0.714)+((PCE2.PID-100)*.098)}

2. IP governor valve opening:

=1.304*{(SC.PID+61.6)-81.6+((PCE1.PID-100)*(-0.2))+((PCE2.PID-100)*.098)}

3. LP governor valve opening:

= 1.379*{(SC.PID+61.6)-108.6+((PCE1.PID-100)*(-0.2))+((PCE2.PID-100)*.098)}

Ratio limiter

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HP driver signal from ratio limiter > 34.9 %

Speed > 6277 rpm

AndIP/LP Extraction enable

IP/LP Extraction enable:

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Turbine protection system

1. Casing temperature protection

2. Differential pressure protection

3. Turbine trips

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Average casing temperature of HP stage less than 160oC

Average temperature difference of the HP and IP stage > 40oC

Average temperature difference of the HP and IP stage < - 40oC

No failure of input signals

Reference speed > 1500 rpm

Reference speed < 2500 rpm

OR

AND

Casing temperature protection

Speedincreaseblocked

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LP stageupstreampressure

LP stageExtractionpressure

SUB

LP stageExtractionpressure

Characteristiccurve

P2

If (P1-P2)>0

P1

AND

No signal failure

Shutdown

Differential pressure protection ( LP stage )

HP stageupstreampressure

HP stageExtractionpressure

SUB

HP stageExtractionpressure

Characteristiccurve

P2

If (P1-P2)>0

P1

AND

No signal failure

Shutdown

Differential pressure protection ( HP stage )

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Turbine trips Power up Minimal two card failure All speed sensor fail TE-5936 Extraction temperature(HP side) high TE-5938 Extraction temperature(LP side) high TE-5934 Exhaust steam temperature high Protech 203 Over speed trip PS-5932 Turbine tripped pressure switch PSHH-5936 Exhaust pressure high high No speed/sticky rotor Micronet Over speed trip HP Redundancy Manager both I/H converters failure IP Redundancy Manager both I/H converters failure LP Redundancy Manager both I/H converters failure Differential Pressure IP side too high Differential Pressure HP side too high Condensate level high high HMI shutdown command

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AND

AND

AND

OR

Card A fail

Card C fail

Card C fail

Card A fail

Card B fail

Card B failShut down

Minimal two card failure

And

Speed signal SE5900A fail

Speed signal SE5900A fail

Speed signal SE5900A fail

Shut down

All speed sensor fail

And

Extraction temperature (HP stage ) greater than 445oC

No signal failure

Shut down

Extraction temperature(HP stage ) high

And

Extraction temperature (HP stage ) greater than 320oC

No signal failure

Shut down

Extraction temperature(LP stage ) high

And

Exhaust steam temperature greater than 170oC

No signal failure

Shut down

Exhaust steam temperature high

Speed > 10150 rpm Trip

Cause Effect

Protech 2o3 Overspeed trip

Trip oil pressure < 1.5kg/cm2

Trip

Cause Effect

Turbine tripped pressure switch

And

If Exhaust pressure > 0.6 bar

If Speed > 500rpm

If the above two conditionspersist for 2 or more seconds

Shut down

Exhaust pressure high high

If Hp valve opening > 30%

Speed < 400 rpmAnd

Shut down

No speed/sticky rotor

Micronet overspeed trip

Speed > 10178 rpm Trip

Cause Effect

OR

OR

AND

If position error(I/H#1)> certain configurablethreshold for a configurable time

When I/H #1 pressure signal fails

When I/H#1 actuator fails

When I/H#1 not available

If position error(I/H#2)> certain configurablethreshold for a configurable time

When I/H #2 pressure signal fails

When I/H#2 actuator fails

When I/H#2 not available

SD

Both I/H converters fail(HP/IP/LP)

AND

Condensate level > 700 mm

If above condition persist for more than 90 sec

Shut down

Condensate level high high

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Woodward system hard ware details

Inputs and out puts

Redundant inputs

Redundant outputs

Redundant sensors

Fault tolerant theory

Latent fault detection

CPU module

Real time SIO module

MPU and analog output module

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Field

wiring

FTM I/OMODULE

VMEMOTHERBOARD

CPU MODULEAND

APPLICATION

Fig: Input flow

CPU MODULEAND

APPLICATIONVME

MOTHERBOARD

I/OMODULE

FTM

Fig: Output flow

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FTM I/OMODULE

FTM I/OMODULE

Sensor 1

Sensor 2

Application

Redundant inputs

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CPU68040

Real time clock

PCMCIAMemory

card

Memory

Applicationmemory

EEPROM Boot upPROM

Switch

BusTime outgenerator

VME busarbitrator

Display port

Serial port

VMEBUS

Watch dogLow VccI/O lockFaultRun

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Thank you