bhel seminar

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


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.


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)


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.


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


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


008

time

Measured value

Set point

Threshold of limiting device

Threshold for response of protective device


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.


028


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


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.


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


046

MS sat.temp. before ESV

HP ESV mid wall temp

Criterion fulfilled

DT (MS sat. Temp. / HP ESV mid wall tem. < X2


047

MS temp. before ESV

MS Sat. temp

Criterion fulfilled

DT (MS Temp. bef. ESV / MS sat. temp. > X4


048

MS temp. before ESV

HP shaft temperature

Criterion fulfilled

DT (MS Temp. bef. ESV / HP shaft temp. > X5


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

bhel seminar

Documents

turbine stress

esv criterion

ip amp

concept amp

ms sat

condamp

turbine protection

ms temp