PPt on Mark Vi Control

OVER VIEW OF GTG PLANT AND CONTROL OF TURBINE

MAIN GB

ALTERNATOR

COMPRESSOR

TURBINE & COMBUSTOR

AUX GB

STARTING DE

LUBE OIL PUMP

Gas Turbine principle Heat added

2

Compressor

1

Heater

cooler

3

Turbine

4

Heat rejected

Description   



At point 1 cold gas enter a compressor to raise pressure At point 2 the gas passes to the heater where temperature of gas is raised At point 3 the hot gas enters the turbine where it expands to a lower pressure. The shaft work developed by turbine flows in two direction. At point 4 the exhaust gas flows to cooler where heat is rejected and gas is restored in initial position

Brayton /Joule cycle 2

3

Pressure

1

4

Volume Two reversible adiabatic or isentropic processes (1-2 and 3-4) Two constant pressure processes (2-3 and 4-1)

Rankine cycle 2

3

Pressure

1

1-2 (BFP) 2-3 (Boiler) 3-4 (Turbine) 4-1 (Condenser)

4 Volume

Open cycle gas turbine Fuel 2

Compressor

Combustion chamber

1

Air from atmosphere

3

Turbine

4 Product of combustion to atmosphere

Salient points    

The source of energy is normally the combustion of fuel in air In closed cycle, gas turbine also product of combustion of fuel and air may be passed through the heater In open cycle cooler is not required The heater is replaced by combustion chamber and fuel is burnt directly in air stream

Open cycle gas turbine (With heater) Heat exchanger 2 Compressor

1

Fuel Combustion chamber 3

Turbine

4 Product of combustion to atmosphere

Air from atmosphere

CONTROL SYSTEM

    

A control scheme of a gas turbine attempts to control the following SPEED TEMPERATURE (COMBUSTOR OUTLET) LOAD START UP CHARACTERISTICS ACCELERATION CONTROL Above characteristics are achieved by modulating fuel flow. Control signal ultimately acts on the fuel valve

CONTROL SYSTEM 



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SPEED: The speed control loop controls the speed of the turbine by controlling the fuel flow . Speed control have speed sensing as input to the controller. TEMPERATURE: Materials used in the hot gas path of gas turbine are stretched much closer to their limits than any other machine. The control system takes design temperature of hot flue gas path material as set point. LOAD: The control loop takes the MW as the set point. The control loop also interferes when rate of loading exceeds a certain point as turbine is loaded fast the damage of the component may occur

CONTROL SYSTEM  START UP CHARCTERISTIC: The control

system brings the gas turbine from zero speed to operating speed using preset level of fuel flow through automatic sequencing of control signals to the accessories, starting device and fuel control system

CONTROL SYSTEM  ACCELERATION CONTROL: One critical

component of the turbine start sequence is the acceleration to synchronous speed. A design acceleration rate must be maintained throughout start up to limit stress on turbine parts.

MARK VI CONTROL SYSTEM  The main function of mark VI control

system are  Speed control during start up  Turbine load control during normal operation on the grid  Protection against turbine over speed on loss of load  Automatic generator synchronization

MARK VI CONTROL SYSTEM  

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It runs on PC based work station using MS window client server architecture. HMI provides operator display and control for mark VI turbine controller HMI contains a number of product feature Dynamic graphics Alarm display Process variable trending Point control display (For maintenance) HMI access security

COMMUNICATION

DCS ETHERNET MODBUS

HMI SERVERNODE

DCS ETHERNET GSM

PLANT DATA HIGHWAY

I/O BOARD

UCVx CONTROLLER

UNIT DATA HIGHWAY

MARK VI TMR CONFIGURATION To other GE control sys Ethernet

TO DCS Backup Protection Primary Controller < P> PROT MOD < R> CONTL MOD PS

Software Voting

< S> CONTL MOD

X

PS < T> CONTL MOD

Y

PS Z Ethernet- IONet

Primary Controller  Control  Protection  Monitoring , , are Control processor Backup Protection  Emergency over speed  Synchro check protection  , , are back up processor

MARK VI BOARDS       

I/O Terminal Board I/O Board Processor Card Communication Card Protective Processor , , Rack Power Supply Power Distribution Board

MARK VI I/O General Purpose I/O  Contact Input  Relay Output  Analog I/O  Thermocouple Inputs  RTD inputs Turbine specific I/O  Vibration Inputs  Speed Inputs  Servo channels for control valves (LVDT or LVDR )  Flame Inputs  Automatic Synchronizing

MARK VI COMMUNICATION External Communication  HMI to Mark VI  HMI to DCS Internal Communication  VCMI & Control processors  DCMI to I/O boards  I/O signal flow  Unit data Highway (UDH)  Ethernet network between controllers and HMI  Plant data Highway (PDH)  Connects HMI server with printers DCS etc

IONET  IONet is Ethernet network used to

communicate data between the VCMI communication board in control module, the I/O boards and three independent sections of protection module  IONet also communicate data between controllers in TMR system

CONTROL SYSTEM TOOLBOX          

Window based application used to configure & maintain Mark VI control equipment Primary function includes Graphical based editor for configuring application code Block macros and module library support Live data block flow diagrams On line code change On line help files I/O configuration & monitoring Signal management and signal trending Report Generation

PASSWORD ADMINISTRATION  

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 

0-Level: Read only like view, monitor live data 1-Level: All function allowed in 0-Level and Change Controller Variables and signals and drive advanced maintenance like change the value of variable, force signals in a controller 2-Level: All function allowed in 0 & 1 Level and full controller access and drive advanced maintenance like make code change, download,put in database and get from data base 3-Level: Drive Block Area and Menu maintenance like alter block area and change application menu structure 4-Level: Fuull Drive access like change GE parameter,edit hardware

CIMPLICITY 

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

Cimplicity is a graphical interface made up of one or more screens used to monitor and control the turbine operation Cimplicity servers allows operator to directly interface to the mark VI controller (UDH) using graphical screen The cimplicity server interface to the mark VI is done by the cimplicity project. This project is controlled by a project file using cimplicity work bench program

TROUBLE SHOOTING TOOLS  Finder/Signal Browser