Turbine governing steam turbines
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TURBINE GOVERNING SYSTEM
PRESENTATION BY
M DEENADAYALAN
C M NIKHIL
B VASANTH KUMAR
TOPICS OF DISCUSSION
INTRODUCTION
CONCEPT OF GOVERNING SYSTEM
FEATURES OF KWU GOVERNING SYSTEM
GOVERNING SYSTEM DEVICES
WORKING OF GOVERNING SYSTEM
HYDRAULIC AND ELECTROHYDRAULIC SYSTEM
PROTECTIVE DEVICES IN GOVERNING SYSTEM
QUERIES
WHAT IS GOVERNING SYSTEM ?
Turbine Governing system is meant for regulation of turbine
speed under no load and varying load condition.
To regulate the steam control valve position and hence load
generated.
To control the initial run up and synchronization of the
machine
To assist in matching the power generated to that demanded
by responding to the network frequency changes.
SALENT FEATURES OF 200 MW KWU TURBINE
GOVERNING SYSTEM
KWU 200 MW turbine is a throttle governed machine.
Two governors, electro-hydraulic and hydraulic are
incorporated. Both the governors are connected in
parallel.
Only one governor can be selected at a time through the
process of hydraulic minimum selection.
The control valve opening depends on secondary oil
pressure and there is a definite relationship between the
opening of HP control valve and IP control valve.
Between 40 to 200MW the turbine load is varied by
changing the HP control valve throttling alone.
HYDRAULIC GOVERNOR SALIENT FEATURES
Hydraulic governor is having only one control
loop called speed controller.
Machine speed is measured and indicated as
primary oil pressure.
Range of speed control is 2800-3210 rpm.
Speed regulation range (droop) of HG is 7%.
HG acts as a back-up to the EHG.
HG can not be isolated mechanically like EHG
and HG is considered to be the primary
governor of the KWU turbine
ELECTRO-HYDRAULIC GOVERNOR SALIENT
FEATURES
EHG consists of three control loops for speed, load and
pressure.
EHG optimizes the turbine life by conservative operation with
the aid of TSE.
Faster response and precise frequency control.
Actual speed of the turbine is measured by using hall probes
Range of speed control is wider (0-3210) rpm.
Speed regulation (Droop) can be changed from 2.5% to 8% in
a step of 0.5% even when the machine runs on load. The usual
setting of droop in EHG is 5%.
EHG can be mechanically isolated by closing the secondary oil
line from the local.
GOVERNING SYSTEM DEVICES
Remote trip solenoids
Turbine trip gear
(Main trip valve)
Starting and load limiting
device
Speeder gear
Auxiliary follow-up piston
Follow-up piston
Hydraulic amplifier
Electro-hydraulic
convertor
Sequence trimming device
Solenoid for load shedding
relay
DIFFERENT OILS USED IN KWU TURBINE
Control oil (source oil)
Auxiliary start-up oil
Start-up oil
Auxiliary trip oil
Trip oil
Auxiliary secondary oil
secondary oil
Test oil
Primary oil
Lube oil
Jacking oil
REMOTE TRIP SOLENOIDS
TURBINE TRIP GEAR
Trip gear is the main protection mechanism of the turbine. It diverts
the control oil coming from the RTS in to TRIP OIL and AUX.TRIP
OIL. Aux.trip oil keeps the trip gear spool valve in open condition so
that uninterrupted trip oil pressure is ensured. Aux.trip oil is also
connected to three hydraulic safety devices namely Over speed , Low
vacuum &Thrust bearing Trip Devices.
STARTING AND LOAD LIMITING DEVICE
USED FOR RESETTING THE TURBINE AFTER TRIPPING
FOR OPENING THE STOP VALVES AND RELEASING THE CONTROL
VALVES FOR OPENING
STARTING DEVICE AT 0% POSITION
BELLOWS COMPRESSED (CONTROL VALVE CLOSED POSITION)
AUX STARTUP OIL RESETS TRIP DEVICES
STARTUP OIL RESETS STOP VALVES (ESVs AND Ivs)
PILOT VALVE(STARTING DEVICE) POSITION RAISED
START-UP OIL AND AUXILIARY START-UP OIL CIRCUITS ARE DRAINED
ESVS OPEN AT 42% AND IVS OPEN AT 56% POSITIONS OF THE STARTING
DEVICE
SPEEDER GEAR
ASSEMBLY OF A BELLOW AND A SPRING
BELLOW COMPRESSION CONTROLLED BY
STARTING DEVICE POSITOIN
SPEEDER GEAR POSITION (ALTERS SPRING TENSION)
PRIMARY OIL PRESSURE
OPERATED FROM UCB OR LOCAL
PRIMARY OIL PRESSURE (SPEED FEEDBACK)
AUXILIARY FOLLOW UP-PISTONS
TEST VALVES
HP/IP STOP VALVES RECEIVE TRIP OIL THROUGH
THEIR RESPECTIVE TEST VALVES
PORT OPENINGS FOR BOTH TRIP OIL AND
START-UP OIL
USED IN RESETTING OF STOP VALVES AFTER
TURBINE TRIP
VALVE CAN BE OPERATED WITH HANDWHEEL
WORKING OF GOVERNING SYSTEM
SPEEDER
GEAR
STARTING
DEVICE
AFUP
HYRAULIC
CONVERTER
FUP
TRIP VALVE
AUX START UP OIL
TO RESET TRIP V/V
EHC
FUP
EHC INPUT
IP SECONDARY OIL
HP SECONDAY OIL
TRIP OIL
TRIP OIL
CONTROL
OIL
AUX TRIP OIL
LOW VACUUM
TRIP DEVICE
OVER SPEED
DEVICE
THRUST
BEARING DEVICE
HP/IP
STOP VALVE
RESET
CONTROL
OIL
TRIP OIL
AUX
TRIP OIL
CONTROL OIL
FROM RTS
