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Control and Instrumentation for Steam Turbines in Power PlantsTRANSCRIPT
Turbines & Compressors EngineeringBharat Heavy Electricals LimitedHyderabad, India
Control and Instrumentation for Control and Instrumentation for Steam Turbines in Power PlantsSteam Turbines in Power Plants
001
Automation: Requirement, concept & Automation: Requirement, concept & SolutionsSolutions
002
• C&I play a major role in realising the following objectives of any power plant
•safety for plant and personnel
•increased plant availability
•longer equipment life
Automation: Requirement, concept & Automation: Requirement, concept & SolutionsSolutions
003
• Safe and Reliable operation of Steam Turbines places heavy demands on the equipment used for Automation and for implementation of dependable and economical solutions.
Automation: Requirement, concept & Automation: Requirement, concept & SolutionsSolutions
004
• The Proven concept of Automation meets the tasks involved in following three levels.•Regular Operation (Monitoring)
•Management of Disturbances (Control)
•Handling of Adverse events (Protection)
Automation: Requirement, concept & Automation: Requirement, concept & SolutionsSolutions
005
Regular Operation
Normal operation of the turbine is checked by supervisory devices such as analog controller, binary control elements and monitoring equipment.
E.g.:gland steam pressure controller, drive control interface for pumps, TSI etc.
Automation: Requirement, concept & Automation: Requirement, concept & SolutionsSolutions
006
Management of Disturbances
The limiting Devices detect deviations from normal operation and initiate counter measures to return the turbine to normal conditions
E.g.:Start-up of stand by pump on low lube oil pressure
Automation: Requirement, concept & Automation: Requirement, concept & SolutionsSolutions
007
Handling of Adverse conditions
Protective equipment shuts off the turbine or parts of the equipment in case of circumstances endangering persons or the turbine which cannot be maintained anymore within safe limits E.g.:Low lube oil pressure protection
Automation: Requirement, concept & Automation: Requirement, concept & SolutionsSolutions
008
time
Measured value
Set point
Threshold of limiting device
Threshold for response of protective device
Automation: Requirement, concept & Automation: Requirement, concept & SolutionsSolutions
009
Modern Digital I&C equipment features a modular design. Accordingly a safe and economical configuration can be customised for any application , tailored to the rating of the turbine.
Typical ConfigurationTypical Configuration
011
Plant information network
REMOTE I/O
FIBRE OPTIC LINK
ENGINEER’S STATION
REMOTE PROESSING UNITS
PLANT SUB-SYSTEMS
MAXLINK
MAXSTATIONS
Redundant 100 Mbps MAXNET
Principle Modules of AutomationPrinciple Modules of Automation
012
• Turbine Interlocks and Protection
• Electro Hydraulic Turbine Control (EHTC)
• Turbine Stress Evaluator (TSE)
• Seal Steam Control
• Turbine Supervisory Instrumentation (TSI)
• Automatic Turbine Run-up System (ATRS)
Turbine Protection: PurposeTurbine Protection: Purpose
013
• To detect incipient irregularities and initiate the safety shutdown
operations so as to minimise damage, repair costs and outages.
• Last link in a chain of measures to designed to prevent or minimise the
damage.
Turbine Protection: categorizationTurbine Protection: categorization
014
• Mandatory trips
• Optional trips
• Mechanical protections
Turbine ProtectionTurbine Protection
015
• Lube oil pressure Very low
• HP steam temperature Very low
• HP steam temperature Very high
• Control Oil Header Pressure Very Low
• Trip Oil Pressure Very Low
• Cond. pressure(vacuum) Very high
• Axial displacement Very high
Description Set Value
< 1.0 Kg/sq.cm
< 515 deg.c
< 4.5 Kg/sq.cm(g)
< 2.0 Kg/sq.cm(g)
> +/- 0.7 mm
> 550 deg.c
> -0.4 Kg/sq.cm(g)
Turbine ProtectionTurbine Protection
016
• Turbine Speed Very high
• Tur. & Gen. Shaft Vibration V. High
• Tur. & Gen. Brg. Temp. V. High
• Emergency Trip Push Button
• H R S G Trip Operated
Description Set Value
> 3300 rpm
> 240 microns
> 115 Deg C
• Generator Trip Operated
Operated
Operated
Operated
• Trip from ATRS Operated
Turbine Stress EvaluatorTurbine Stress Evaluator
016
• The steam temperatures inside the turbine vary with change in operating conditions( start-up,loading, load change, shutdown).The resulting temperature differences give rise to material stresses.• TSE provides the basis for operating
with maximum permissible thermal stress.
Turbine Stress Evaluator: DesignTurbine Stress Evaluator: Design
017
• The input parameters are the wall temperature sensors(thermocouples) measured at characteristic points of turbine like •Admission •Turbine shaft
Turbine Stress Evaluator: DesignTurbine Stress Evaluator: Design
018
Turbine Stress Evaluator: Design Turbine Stress Evaluator: Design TSE Limit curvesTSE Limit curves
019
Tm
DTallow
Seal Steam Pressure Control Seal Steam Pressure Control
020
Electro Hydraulic Turbine Control Electro Hydraulic Turbine Control (EHTC) (EHTC)
021
• High flexibility
• High operational safety & reliability
• Easy integration with TSE, ATRS.
Electro Hydraulic Turbine Control Electro Hydraulic Turbine Control (EHTC) (EHTC)
022
HP VLV. LIFT REF. SET.
SPEED CONTR
HP INLET PR.CONTROL
M
N
I
HP I/H CONV.
LP INJ. PR.CONTROL
IP INJ. PR.CONTROL SEL. LOGIC IP I/H CONV.
SEL. LOGIC LP I/H CONV.
EHTC: Speed control loop EHTC: Speed control loop
023
• Control speed during start-up and synchronisation
• Turbine stress margins limit the speed acceleration rate
Acceleration rate
TSE temperature margin
•Speed acceleration monitoring
EHTC: HP pressure control loop EHTC: HP pressure control loop
024
• Sliding pressure mode
• Limit pressure mode
EHTC: IP & LP Injection Pressure EHTC: IP & LP Injection Pressure control loop control loop
025
• IP injection pressure control maintains IP injection pressure• LP injection pressure control maintains
LP injection pressure
TSI monitors TSI monitors
026
•Relative shaft vibration
•Thrust position
•3500 Monitoring System
Automatic Turbine Runup System Automatic Turbine Runup System (ATRS) :Philosophy (ATRS) :Philosophy
027
•Subgroup Control (SGC)
e.g.:Oil system,condensate &evacuation system and Turbine system
•Subloop Control (SLC)
e.g.:Lube oil pumps etc.
•Control Interface(CI)
e.g:main oil pump,jacking oil pump etc.
Automatic Turbine Runup System Automatic Turbine Runup System (ATRS) :Philosophy (ATRS) :Philosophy
028
Automatic Turbine Runup System Automatic Turbine Runup System (ATRS) :Philosophy (ATRS) :Philosophy
029
• SGC Executes commands to bring the equipment upto a particular state and contains the start-up and shutdown programme of the particular group.
• The programme comprises of different steps
• SGC issues commands to SLC/CI at each step
• Provision for “monitoring time” and
“waiting time” at each step
Automatic Turbine Runup System Automatic Turbine Runup System (ATRS) :Philosophy (ATRS) :Philosophy
030
• OPERATOR GUIDE MODE:
In this mode data is received from plant but commands are not issued.Useful for commissioning and training.•STEP MODE:
In this mode programme is executed one step at a time.Useful when system criteria is met but cannot proceed because of switch/transmitter malfunctioning.
Automatic Turbine Runup System Automatic Turbine Runup System (ATRS) :Philosophy (ATRS) :Philosophy
031
• CONTROL INTERFACE:
It is the interface between SGC/SLC and MCC.It prioritises the commands from SGC/SLC and issues commands to MCC.
• SUB LOOP CONTROL:
It enables the process condition for automatic start-up of the drive.
Automatic Turbine Runup System Automatic Turbine Runup System (ATRS) :SGC oil system(ATRS) :SGC oil system
032
ATRS :Oil system OperationATRS :Oil system Operation
033
•STEP 1: Starting Step.
•STEP 2: SLC Main oil pumps ON.
•STEP 3: Oil temperature control auto mode.
•STEP 4: SLC EOP on and SLC JOP 1 & 2 on.
•STEP 5: Turning gear on.
•STEP 6: checking for speed > 540 rpm.
•STEP 7: checking for jacking oil pumps off.
•STEP 8: check for turbine speed < 510 rpm.
If not go to step-1.
ATRS :Oil system shutdownATRS :Oil system shutdown
034
•STEP 51: SLC Turning gear put off.
•STEP 52: check for turbine standstill.
•STEP 53: waiting
•STEP 54: SLC jacking oil pumps off.
•STEP 55: SLC oil pumps off.
ATRS :Cond&evac operationATRS :Cond&evac operation
035
ATRS :cond&evac OperationATRS :cond&evac Operation
036
•STEP 1: SLC CEP & GSCEF on.
•STEP 2: Check back for CEP & GSCEF on.
•STEP 3: Vacuum breaker valve close;
Gland steam controller close/manual
•STEP 4: Vacuum pump1 & 2 on.
•STEP 5: Air inlet valve 1 & 2 on.
•STEP 6: Gland steam controller put on auto.
•STEP 7: check for cond.press < 0.1 kg/sq.cm(a) and load >5%.
ATRS :cond&evac OperationATRS :cond&evac Operation
037
•STEP 8: switch off unselected vacuum pump.
•STEP 9: check for cond.press > 0.15 kg/sq.cm(a).
If yes go to step 1 / if not go to step 10
ATRS :cond & evac shutdownATRS :cond & evac shutdown
038
•STEP 51: switch off vacuum pump 1&2, air
inlet valves 1&2 close.
•STEP 52: Vacuum breaker valve open.
•STEP 53: Gland steam control close.
•STEP 54: SLC CEP and GSCEF off.
ATRS :Turbine operation release ATRS :Turbine operation release criteriacriteria
039
•position setpoint turbine controller<0%
•generator breaker off
•synchroniser off
•Vent before ESV not closed
•ESV closed
ATRS :Turbine operationATRS :Turbine operation
040
ATRS :turbine OperationATRS :turbine Operation
041
•STEP 1: SLC drains on.
•STEP 2: Check for cond. Pr, Trip Oil Pr & DT
casing top/bottom.
•STEP 3: no command.
•STEP 4: Check for X1 & X2 criterion.
•STEP 5: HP ESV open.
•STEP 6: check for HP ESV open.
•STEP7: Check for X4 & X5 criterion.
ATRS :turbine OperationATRS :turbine Operation
042
•STEP 8: raise the speed SP to warm-up speed.
•STEP 9:check for actual speed reached for warm-up speed .
•STEP 10: check for X6 criterion.
Check for TSE margin>30K
•STEP 11: no command.
•STEP 12: Raise Turbine speed to rated speed.
ATRS : turbine OperationATRS : turbine Operation
043
•STEP 13: Check for actual speed reached rated speed.
•STEP 14: AVR auto
•STEP 15: Waiting
•STEP 16: Synchroniser on.
Check for generator breaker on.
•STEP 17: load to auxiliary load.
ATRS :turbine shut-downATRS :turbine shut-down
044
•STEP 51: SLC drains on.
•STEP 52: HP, IP & LP control off.
•STEP 53: lower speed SP to 0% .
•STEP 54: actuate turbine trip channels
synchroniser off
generator field breaker open
•STEP 55: vent & drain before ESV open.
ATRS :turbine Operation ATRS :turbine Operation X1 criterionX1 criterion
045
MS temp. before ESV
HP ESV mid wall temp
Criterion fulfilled
DT (MS Temp. bef. ESV / HP ESV mid wall tem. > X1
ATRS :turbine Operation ATRS :turbine Operation X2 criterionX2 criterion
046
MS sat.temp. before ESV
HP ESV mid wall temp
Criterion fulfilled
DT (MS sat. Temp. / HP ESV mid wall tem. < X2
ATRS :turbine Operation ATRS :turbine Operation X4 criterionX4 criterion
047
MS temp. before ESV
MS Sat. temp
Criterion fulfilled
DT (MS Temp. bef. ESV / MS sat. temp. > X4
ATRS :turbine Operation ATRS :turbine Operation X5 criterionX5 criterion
048
MS temp. before ESV
HP shaft temperature
Criterion fulfilled
DT (MS Temp. bef. ESV / HP shaft temp. > X5
ATRS :turbine Operation ATRS :turbine Operation X7 criterionX7 criterion
049
MS temp. before ESV
HP shaft temperature
Criterion fulfilled
DT (MS Temp. bef. ESV / HP shaft temp. < X7
ConclusionConclusion
BHEL is capable of providing complete control and instrumentation solutions which shall be
Cost effectiveOf latest technology Meeting the customer’s specification
requirements
053