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New features of 660 MW UnitsNew features of 660 MW Units
Sipat Super thermal power project
Turbine Maintenance
New features of 660 MW units
• Constructional features
• Operational features
• Lube oil system
• Governing system
• Feed water system
• Turbine Auxiliaries
Specifications• Make OJSC Power machines, Russia
• Design LMZ, Russia
• Type K-660-247Four Cylinder, tandem compound, Reheat, Condensing
TurbineSpring deck foundation
• Stages HPT, reverse flow, 17 (1-control stage,16 Reaction stages)
IPT 11 X 2 impulse stages.
LPT 2 nos. - 5 X 2 impulse stages.
• No of HP Control Valve 4• No of IP Intercept valves 2 • No of IP Governing valves 4• Over all length of turbine 35.8 Mtr• Direction of Rotation Clockwise (Viewed from front
pedestal towards Generator)
Main features• Turbine: HPT, IPT, LPT1 and LPT2
• Two condensers for Main Turbine
• TG Bearings: 12
• Turbine Stop Valves: 04 (HPSV-1&2, IPSV-1&2)
• Turbine Control Valves: 08 (4 HPCV & 4 IPCV)
• CRH Check Valves: 02 ( With Bypass lines for warm up)
• IP Turbine has throttle governing – all four control valves open simultaneously
• HP Turbine has nozzle governing – all four control valves open in preset sequence
• LP heaters – 1a, 1b, 2, 3 & 4
• HP heaters – 6A, 6B, 7A, 7B, 8A & 8B
• Steam coolers – one each for HPH 6A & 6B
• 2 MDBFP (2 X 30%)
• 2 TDBFP (2 X 50%)
• Separate condensers and vacuum pumps for TDBFPs
GoverningBox
HP Turbine IP Turbine LP Turbine # 1 LP Turbine # 2
MS CRH HRH
HPH#8A
HPH#7A
HPH#6A
CR
H
LPH#4
LPH#3
LPH#2
LPH#1LPH#1
Deareator
HPH#8B
HPH#7B
HPH#6B
Steam cooler
HPH#8A
HPH#7A
HPH#6A
LPH#4
LPH#3
LPH#2
LPH#1bLPH#1a
Deareator
HPH#8B
HPH#7B
HPH#6B
Steam cooler
540ºC 247 KSc
349ºC 68.8 KSc
298ºC 47.9 KSc 565ºC 43.1 KSc
Main parametersParameters Units Value
Live steam consumption, HPT inlet t/h 2023.7
Rated total pressure of live steam, HPT inlet MPa (kgf/cm 2 abs) 24.2 (247)
Live steam rated temperature °С 537
T after HPT exhaust °С 297.8
P after HPT exhaust MPa (kgf/cm 2 abs)4.8 (47.9 kgf/cm2)
Steam absolute pressure before IP SV MPa (kgf/cm 2 abs)4.3 (43.1 kgf/cm2)
Live steam consumption , IPT inlet t/h 1678.5
steam temperature before IPSV °С 565
steam absolute pressure in condenser MPa (kgf/cm 2 abs) 0.105
Inlet condenser CW temp °С 33
cooling-water consumption m3/h 64000
Extraction Steam parametersLocations Pressure (bar) –
AbsoluteTemperatures (oC)
Initial steam HPT inlet 247 537
HP cylinder exhaust 48 298.50
IP cylinder stop valve Inlet 43.20 565
Extraction 8 (HPT 13th stage to HPH 8) 68.8 349
Extraction 7 (CRH to HPH 7) 45.6 295.62
Extraction 6 (IPT 3rd stage to HPH 6 & TDBFP)
21.7 470
Extraction 5 (IPT 6rd stage to Deareator) 11.34 374.28
Extraction 4 (IPT 8th stage to LPH 4) 6.25 301
Extraction 3 (IPT 11th stage to LPH 3) 2.97 214
Extraction 2 (LPT 2nd stage to LPH 2) 0.624 0.79% / 89
Extraction 1 (LPT 4th stage to LPH 1) 0.264 4.38% / 68
LP cylinder exhaust 0.105 7.84%
Operational features
• Turbine rolling by IPT
• HPC & IPC flange heating system
• IP Turbine rotor cooling system
• Turbine motorized barring gear
• Jacking oil for bearing shell & rotor
• No Main oil pump
• Separate governing box in front pedestal
• High pressure governing system
• Pressurized damper tanks with no separate air / h2 seal oil pumps
• HP / LP Bypass control system similar to 500 MW unit HP Bypass
system
HP Turbine
• Reverse flow turbine (1 – 9 stages: left flow, 10 -17
stages: right flow)
• 17 stages (1 control stage + 16 reaction stages.
• Type of Casing: Horizontally split inner & outer casing
• Four main steam inlet and two cold reheat outlet
• No balance drum / balance piston arrangement
• Extraction steam from HP Casing in 13th stage to HP
Heater # 8.
• Stationary blades are fixed in casing. No diaphragms in
HPT
• Flange heating system from HRH source.
HP Turbine
HP Turbine
Material:
– HP outer casing: 15Cr1Mo1V
– HP blade carrier/casings: 15Cr1Mo1V
– HP shaft: 25Cr1Mo1V
– HP Turbine Moving Blades first stage (1-5): 18Cr11MoNiVNb
– HP Turbine Moving Blades stages (6-17): 15Cr11MoV
– HP Turbine Fixed Blades first stage (1-5): 18Cr11MoNiVNb
– HP Turbine Fixed Blades stages (6-17): 15Cr11MoV
– HPT Casing Joint Bolts: 20Cr1Mo1V1TiB, 25Cr1MoV,
18Cr12WMoNbVB
– Shaft Couplings: 25Cr1MoV
– HP Labyrinth Seals: 20CrMo, 15CrMo
IP Turbine
• Double flow turbine (2 X 11 impulse type)
• Type of Casing: Horizontally split inner & outer casing
• All four HRH steam inlet from bottom side
• IP Turbine stationary blades (1st & 2nd stages) cooling
system from CRH & HRH source.
• Flange heating system from HRH source.
• Stationary blades are fixed in diaphragms
• Balance holes: 10 holes / ST (2nd stage to 11th stage)
IP Turbine
IP Turbine
IP Turbine
Material:
– IP outer casing: 15Cr1Mo1V
– IP Inner casing: G-X 12CrMoVNbN9-1
– IP shaft: 26CrNi3Mo2V
– IP Turbine Moving Blades first stage (1-3): 18Cr11MoNiVNb
– IP Turbine Moving Blades stages (4-11): 15Cr11MoV
– IP Turbine Fixed Blades first stage (Ist ST): 18Cr11MoNiVNb
– IP Turbine Fixed Blades stages (2-11): 15Cr11MoV
– IPT Casing Joint Bolts: 20Cr1Mo1V1TiB, 25Cr1MoV,
– 18Cr12WMoNbVB
– Shaft Couplings: 25Cr1MoV
– IP Labyrinth Seals: 20MnSi
No of LP Turbine: 2
Type of turbine cylinders: Double flow
Type of Casing: Horizontally split inner & outer casing
No of Stages: 2 X 5 (impulse)
Last Stage Blade height: 1000 mm
Extraction Steam at 2nd stage & 4th Stage
Last stage – locking shrouded blades with lacing wire
LP Turbine # 1 & 2
LP Turbine 1 & 2
LP Turbine
Material:
– LP inner & outer casing: Steel 3
– LP shaft: 26CrNi3Mo2V
– LP Turbine Moving Blades first stage (1-2, 3-4): 20Cr13,
– 15Cr11MoV
– LP Turbine last stage moving blades: 13Cr11Ni2W2MoV
– LP Turbine Fixed Blades first stage (1-4): 12Cr13
– LP Turbine Fixed Blades stages (5): 08 Cr13
– LPT Casing Joint Bolts: Steel 25
– Shaft Couplings: 25Cr1MoV
– LP Labyrinth Seals: 26CrNi
LP Turbine
Flange heating system
To condenser
From HRH
From HRH
1. Put into operation by operator during cold and warm start-ups of the turbine
2. To decrease differential temperature of HPC and IPC flanges, and to prevent inadmissible relative extensions of HPC and IPC rotors
3. Without flange heating system turbine can be started up but the start up time shall be increased by 30-60 minutes
HPC Flange heating
• HPC flange heating is put into operation when relative expansion of
rotor > +3.0 mm or differential temperature across the width of any
HPC flanges > 40 ºC.
• Conditions for putting in operation:– Steam pressure in hot reheat pipeline is above 6.0 kg/cm2
– Steam temperature in hot reheat pipeline is above 150 ºC
– Pressure in main turbine condensers is below 0.5 kg/cm2 (abs).
• Supply header temperature > 150 ºC and 35 ºC above outer surface
temperature of any flange.
• In auto mode initial 15 min the pressure is maintained at 0.5 Ksc
• After 15 mins, pressure is increased to 5 Ksc and drain valve is
closed.
HPC Flange heating
• HPC flange heating is put out from operation when
– Relative expansion of rotor < - 1.0 mm or
– Temperature difference between outer surface temperature of any
HPC and HPC top or bottom > 80 ºC or
– if the HPC top metal temperature exceeds 350 ºC
• HPC flange heating is put out from operation by
– The gate valve closes on the HPC flange heating steam supply
line.
– Control valve closes and drain opens
IPC Flange heating
• IPC flange heating is put into operation when relative expansion of
rotor > +1.0 mm or differential temperature across the width of any
HPC flanges > 40 ºC.
• Conditions for putting in operation:– Steam pressure in hot reheat pipeline is above 6.0 kg/cm2
– Steam temperature in hot reheat pipeline is above 150 ºC
– Pressure in main turbine condensers is below 0.5 kg/cm2 (abs).
• Supply header temperature > 150 ºC and 35 ºC above outer surface
temperature of any flange.
• In auto mode initial 15 min the pressure is maintained at 0.5 Ksc
• After 15 mins, pressure is increased to 5 Ksc and drain valve is
closed.
IPC Flange heating
• IPC flange heating is put out from operation when
– Relative expansion of rotor < - 1.0 mm or
– Temperature difference between outer surface temperature of any
IPC and IPC top or bottom > 80 ºC or
– if the IPC top metal temperature exceeds 350 ºC
• IPC flange heating is put out from operation by
– The gate valve closes on the IPC flange heating steam supply line.
– Control valve closes and drain opens
IP Rotor cooling system
• IP Turbine rotor cooling system is provided from HRH and CRH source.
Screw Jacks
HRH Strainer
660 MW Turbine casings
Bearing No 2
Bearing No 3
LUBE OIL SYSTEM
• Turbine oil is ISO VG 32
• MOT Capacity : 58 m3
• 2 AC Lube oil pumps
• 1 DC lube oil pump
• Deaeration screen + fine mesh screen
• Duplex filters fineness: 25 µm• fine cleaning filter with fineness of 12-15 µm
• Oil draining to Emergency lube oil tank in case of
emergency
• PCV Bypass with throttling orifice which provides lubrication even at fully closed control valve
Equipment Capacity (m3/hr)
Head (Ksc)
AC Lube oil pump 300 4.3
DC Lube oil pump 250 2.0
TG LUBE OIL SYSTEM
M M M M
M
M
GENERATORECT
M
M
COOLER ACOOLER B
DUPLEX FILTER A
DUPLEX FILTER B
DMCW O/LDMCW INLET
HPCIPCLPC1LPC2
HEATER
R/C PUMP
OIL TRAP
VAP.EX.FAN
MAIN OIL TANK
MOP A MOP B EOP A EOP B
PCV
LUBE OIL RETURN HEADER
LUBE OIL SUPPLY HEADER
FROM TOP UP OIL TANK
FRO
M S
EA
L O
IL S
YS
TE
M
FRO
M P
UR
IFIE
R U
NIT
TO
SE
AL O
IL SYS
TE
M
TO
PU
RIFIE
R U
NIT
TO EOT
TO
JAC
KIN
G O
IL SYS
TE
M
TO TRANSFER PUMP
VAPOUR LINE
FILTRATION UNIT
• Bearings
HPT Front N1 (Multi wedge Tilting type JB)
HPT Rear N2 (Multi wedge Tilting type JB)
IPT Front (TB) N3
IPT Rear N4
LPT-1 Front N5
LPT-1 Rear N6
LPT-2 Front N7
LPT-2 Rear N8
Generator Front N9
Generator Rear N10
Exciter Front N11
Exciter Rear N12
Turbine Bearings
Lube oil return
Lube oil supply
Vapor exhauster line
HPC FRONT BRG
Bearing & Pedestals
Lube oil return line
Lube oil supply
Vapour exhauster
BEARING PEDESTAL CONNECTIONS
Oil inlet to Bearing chamber
Shell N Dia of orifice to standby tank
Dia of orifice to shell
Pressure at stand by tank
N1 39 20 0.9 Ksc
N2 39 20 0.9
N3 39 39 0.4
N3 Shell holder ---- ---- ----
N4 39 29 1.0
N5 39 29 1.05
N6 30 29 0.95
N7 30 29 0.95
N8 33 29 0.95
N9 29 29 0.75
Barring gear Barring speed 1.05 rpm
Installed in the bearing between
Brg No.4 & Brg No.5
Cut in 800 rpm / cut out 1200 rpm
Components:
Barring gear motor
3-stage reducer and free
wheel clutch (on turbine rotor)
For Hand barring special
handle is provided at first
stage of Reduction gear. (15-
20 min by 180 deg manually)
Reduction gear & Free wheel clutch system
Barring gear motor (30 KW, 735 rpm,)
Hand drive for hand barring
Reduction gears (3 stages)
Free wheel clutches
Rotor shaft, 1.05 rpm
1
2
3
TG ROTOR JACKING OIL SYSTEM
GENERATOR
M M
AC ROTOR JOP
DC ROTOR JOP
LUBE OIL COOLER OUT LET
BRG1
HPCLPC 1 IPCLPC 2
BRG2BRG3BRG4
BRG5BRG6
BRG7BRG8BRG9
BRG10
FROM MOT
H= 120 ksc
rRotorRotor Jacking oil
Oil outlet points
Oil inlet from JOP discharge header
TG ROTOR JACKING OIL SYSTEM
ROTOR JOP(AC) PROTECTIONS & INTERLOCKSRotor oil jacking pump (AC) starts automatically if
o Speed becomes lower than 800 rpm(but not zero i.e >3 rpm) &
o Vacuum breaking valves are closed
Rotor oil jacking pump (AC) stops automatically if
o Speed becomes higher than 1200 rpm (OR)
o Oil Pr at p/p suction decreases down to L=0.8 ksc (OR)
o After pump start oil pressure in the discharge header < LL=20 ksc (Td=60 sec).
o Any Fire Key activated.
Remotely from CCB motor can be started if
Pump suction is higher than 0.8 ksc
Fire key not activated.
ROTOR JOP(DC) PROTECTIONS & INTERLOCKS
Rotor oil jacking pump (DC) starts automatically with Time delay 10sec , if
o Oil pressure in the rotor discharge jacking oil header < 45 ksc.&
o Speed becomes lower than 800 rpm(but not zero) &
o Vacuum breaking valves are closed &
o Turbine stop valves are closed
Rotor oil jacking pump (DC) stops automatically if
o Oil Pr at p/p suction decreases down to L=0.8 ksc (OR)
o After pump start oil pressure in the discharge header is lower than LL=20 ksc (Td=60 sec).
o Any fire key activated.
Remotely from CCB motor can be started if
Pump suction is higher than 0.8 ksc
Fire key not activated.
TG BEARING JACKING OIL SYSTEM
GENERATOR
M
AC BRG.JOP
FROM OUT LET OF COOLER
BRG1
HPCLPC 1 IPCLPC 2
BRG2BRG3BRG4BRG6
BEARINGHOUSING
ORIFICEBRG5BRG7BRG8
BRG9BRG10
FROM MOT
JOP suction Header
Jop Discharge header
Bearing jacking oil
During turbine start-up and unit load
variation conditions the rotor neck
displacement occurs in the bearing
inserts.
To level the position relative to the
rotor necks the bearing jacking oil
pump starts.
The rotor neck displacement(X-Y) in
the inserts < 0.1mm Bearing JOP
stops.
No Standby Bearing JOP.
Brg Jacking oil
Bearing jacking oil
BEARING INSERT JOP PROTECTIONS & INTERLOCKS
Bearing insert JOP starts automatically if
Rotor neck displacement > 0.1 mm relative to the inserts of any of
bearings 4-9.
provided – 1. Rotor JOP Header Pr >45 ksc.(OR)
2. Speed is higher than 1200 rpm.
Bearing insert JOP stops automatically with time delay of 30 sec if
Rotor neck displacement < 0.1 mm relative to the inserts of any of
bearings 4…9
Oil Pr at p/p suction decreases down to L=0.8 ksc (OR)
After pump start oil pressure in the discharge header is lower than LL=20
ksc (Td=60 sec).
Any fire key activated
GOVERNING SYSTEM
• High pressure governing & a very compact governing & a
concealed governing.
• High pressure governing : Advantages: Faster response of
systems & smaller sizes of the systems
• Disadvantages: leakages from seals & failure of devices.
• Governing block located at turbine bearing pedestal no. 1
• Electro Hydraulic governing only
• 4 Nos HP control valves , 4 Nos IP control valves with individual
EHCs ie 8NOS. of EHC
• HPT – Nozzle governing , IPT – Throttle Governing
COMPONENTS OF 660 GOVERNING SYSTEM
• Oil supply
• Spring loaded Accumulator
• Governing block
• EHC (Electro hydraulic converter)
• Stop valve servomotors
• Control valve servomotors
• Pilot valves
• Extraction stop v/v
• CRH FCNRVs.
• CF regeneration system – Resin based Vacuum dehydrator
cum filtration units
M
M
M
M M
VAP.EX.FAN
FROM GOV BOX
FROM CF PURIFIER
FROM CLEAN CF TANK
MAIN CF TANK V= 6.9 M3
FROM GOV SYSTEM
TO CF PURIFIER
CF TRANSFER PUMP
TO CLEAN CF TANK
TO CF DRAIN TANK
TO CF DRAIN TANK
CF PUMP A
CF PUMP B
DUPLEX FILTER
CF COOLER
STABILIZED PR. LINENON-STABILIZED PR. LINE
ACCUMULATOR
TODRAINHEADER
CF SEPARATOR
OIL SUPPLY UNIT
• Two motor driven centrifugal pumps (2 x 100%) are of 30.5
T/hr. design capacity and 50ksc head with one in standby
located at 0m height.
• Discharge of oil to system via two headers :
– Stabilized pressure header (50ksc).
– Unstabilized pressure header (50 ksc).
– Stabilized header (50NB) provides control oil to all SVs &
EHCs through governing block.
• Non stabilized header (125NB) feeds oil to servomotor of all
SV & CV.
• Spring loaded mechanical type having working vol :40L
connected to Non stabilized pressure header
SCHEME OF 660 MW Governing System
GOVERNING BOX
• Location : Bearing pedestal 1.
• Components in governing box
– Control gear
– Over speed governor
– Trip solenoids
– Test electromagnets
– Manual trip buttons.
– Intermediate shaft.
– Intermediate shaft lever.
– Pressure limiting device.
– Test valve.
Control gear
Intermediate shaft lever
Test valve
GOVERNING BOX
GOVERNING BOX
Stabilized oil (50 ksc)
To SV
To EHC
CONTROL GEAR
• Acts like a starting device.
• Inlet supply : 50 ksc stabilized oil from pump.
• It generates oil for
1. Resetting (cocking) of overspeed
governor(OG) slide valve(50 ksc).
2. Line of protection (50 ksc) to OG & trip
solenoids
3. Signal oil for stop valve (50 ksc) via OG.
4. Control line to EHC through pressure limiter
(35 ksc).
• The generation of oil carried out while rotating
Control gear from its position 00 to 900 either
by operator command or hand wheel.
OVERSPEED GOVERNOR• Heart of governing system.
• Main purpose to cut in & cutoff
signal oil supply to all S.V.
• Ensures draining of S.V signal oil
and EHC signal oil at the time
turbine protection action.
• Signal oil enters in 111% OG and
comes out from 110% OG.
• In case of protection oil is drained,
results pressure drop in protection
line and due to pressure in
cocking line & Inlet SV line OG
pilot valve moves down which cuts
the oil supplying to S.V & EHC
and connects it to drain.
111% OVERSPEEDING
OG2
110% OVERSPEEDING
OG1
TEST VALVE
• Ensure 50ksc oil supply to fly
bolts under oil injection testing.
• Oil supply done under two
conditions:
1. Load condition.
2. Idle running condition
INTERMEDIATE SHAFT LEVER
TEST VALVELEVER
INTERMEDIATE SHAFT
• A device which links fly bolts to OG pilot valves.
• Three position linking mechanism
– 1. when pressed : OG1(110%) switched out.
– 2. when pulled : OG2(111%) switched out.
– 3. At mid position : OG1 & OG2 are in service.
• Play role in :
– Overspeeding (110% & 111%).
– Oil injection testing.
INTER
MED
IATE S
HA
FT
Turbine main shaft
O.G
Fly bolts @ 1800
OG2
OG1
OG 1 IN SWITCHED OUT CONDITION
OG 2 IN SWITCHED OUT CONDITION
OG2
OG1
Test electromagnets
box
Trip Solenoid 1With manual trip button
Trip Solenoid 2With manual trip button
ONE SET OF MS STOP & CONTROL V/V
STABILISED OIL(50ksc)
UNSTABLISED OIL STREAM
CONTROL OIL FOR EHC(35ksc)
CONTROL OIL FOR STOP V/V
CONTROL OIL FOR CRH NRVS
Head oil I/L
Drain oil above piston
Head oil I/L to servomotor
Drain oil above piston
Tie rods Pilot v/v
HP STOP VALVE IP STOP VALVE
Head oil I/L
Drain port
Control oil I/L
Head oil I/L
CAMATT LEVER
FEED BACK LEVERS
TIE RODS
HP CONTROL VALVE
EHC (ELECTRO HYDRAULIC CONVERTER)
• It consist of EMC and summator
• EHC’s are used for controlling Control
valve for HPT & IPT.
• Control oil for EHC(35ksc) and
stabilized oil(50ksc) are used for the
operation of EHC.
• For ‘0’ signal from Turbine controller
output pressure is equal to 0, because
of draining.
• Output pressure signal also goes for
opening CRH FCNRV.
• Loss of control oil pressure(35ksc)
results zero output pressure from EHC
to CONTROL V/VS.
HEAD OIL/STABILISED OIL I/L (50 KSc)
I/L CONTROL OIL PR FROM GOV BLOCK (35 KSc)
O/L CONTROL OIL / SECONDARY OIL
Control oil/secondary oil from EHC : 1&2 for CRH NRVS
Head oil/un stablised oil
CRH FCNRV
ATT• TESTING OF STOP VALVE
– Testing of SVs is carried with a drive of AC motor mounted on SVs.
– Load range for testing of full closing SV : 30%-75%.– Load range for testing of partial closing SV : 30%-
100%.– Test of full or partial closing is carried out separately
for each SV.– As per OJSC’s guidelines:
• Full closing test carried out once in a month• Partial closing test carried out once in a week.
ATT• TESTING OF CONTROL VALVE
– Test for partial closing and opening of the CV is performed
from the turbine controller i.e. EHC signal.
– Test only carried out on fully open CV.
– Turbine load range during testing : 40%-100%.
– During testing EHCs are controlled by test program.
– As per OJSC’s guideline testing of partial closing of CV is
carried out once in a week.
– Test of partial closing is carried out separately for each
CV.
ATT• TRIP SOLENOID TESTING
– The test program for trip solenoid is used to monitor
operation of solenoid protection valves during turbine
operation.
– Trip solenoid gets isolated from main circuit by the help of
corresponding test electromagnet for testing.
– As per guideline testing of trip solenoids carried out once
in a month.
– In case of any protection acts during testing ; testing
program is stopped and testing mechanism set into initial
position.
Governing System
• HPT control valves open only after achieving preset load (12% of 660 MW)
• Opening time of control valve is 1.5 sec
• Closing time of Stop valve in case of operation of protection is 0.3 sec
• Turbine maximum speed is restricted to 108% in case of generator disconnected from grid
• Over speed protection system stops steam supply in HPC in < 0.5s
• Speed Controller Droop is adjustable from 2.5% to 8% (with dead band of 0.04%)
Rolling Speed Gradient CurveSpeed gradients as per Manufacturer’s start up curve are as follows:
Rolling Condition Target Speed Preset Time Min. Halt Time
Cold Startup ( > 72 H )
3 - 500 rpm 150 sec 300 sec
1200 rpm* 550 sec 300 sec
3000 rpm 630 sec --------
Between 36H – 72H
3 - 500 rpm 75 sec 120 sec
3000 rpm 240 sec --------
Between 8H – 36H 3 - 3000 rpm 360 sec --------
Between 2H – 8H3 - 3000 rpm 300 sec --------
Control Valve Opening Curve
Turbine Start Up Sequence• Start Turbine rolling with Speed Control on from barring speed to
500 rpm
• After achieving desired criteria, raise speed set point to 1200 rpm*
and subsequently to 3000 rpm
• After synchronization Load Controller gets switched On – raise
load > 80MW when “HPC ON” signal is generated
• Turbine Pressure Control will be automatically switched On
• After HPCV demand crosses 80%, switch ON Position controller
to hold 80% as the o/p to control valves for raising pressure to
rated value
• Switch ON Pres. Controller to raise load to rated value
• Switch ON Load Control after load reaches the rated value
START UP CURVES OF TURBINE AFTER SHUTDOWN OF THE UNIT
Start Up Curves Nomenclature• To – S.H Live steam temperature.
• Trh – R.H steam temperature
• Po – S.H outlet steam pressure
• Prh – R.H. steam pressure
• Go – Electrical Load of TG
• Ne – Live steam flow from boiler
• N – Turbine rotor speed
• A – Steam Admission
• B – Synchronization
• C – HPC switch on
• D – HPCV open with 20% Throttle reserve & Loading with constant
HPCV position & HP heaters charged
• E – HPCV no-3 opening. Throttle pressure reduced
• F – Full Load
START UP CURVES OF TURBINE AFTER SHUTDOWN OF THE UNIT
START UP CURVES OF TURBINE AFTER SHUTDOWN OF THE UNIT
Turbine Protection System
Hydraulic Protection: Apart from the Electrical Trip, Turbine is equipped with the following Hydraulic Protections:
1. Local Manual Trip (1V2)
2. Over speed Trip #1 at 110% of rated speed
3. Over speed Trip #2 at 111% of rated speed
4. Governing oil pressure < 20 Ksc
CONDITIONS OF TRIPPING THROUGH TRIP SOLENOID
HOTWELL 1 HOTWELL 2
CEP-A CEP-CCEP-B
CPU
GSC
LPH1.1
LPH1.2
LPH 2LPH 3LPH 4
DEAERATOR
DRIP P/P-A
DRIP P/P-B
CEP-A
DRIP P/P-ADRIP P/P-ADRIP P/P-A
CONDENSATE SYSTEM
Feed water system
• 2 X 50 % TDBFP– Separate Condenser, CEP, Vacuum pump system
• 2 X 30 % MDBFP
• HP Heaters 6A/6B, 7A,7B, 8A/8B and two steam coolers
for 6A/6B.
• 3 way quick closing bypass valves system for HP Heater
feed water isolation.
Boiler feed pump’s• MDBFP’s ( 2 x 30 % )• TDBFP’s ( 2 x 60 %)
BFP combintaion LOAD
02 TDBFP 100 %
01 TDBFP & 02 MDBFP 100%
01 TDBFP & 01 MDBFP 95%
01 TDBFP 65%
02 MDBFP 60%
01 MDBFP 30%
MDBFP No of stages -07 Tapping stage for RH spray -02 Capacity- 769.95 T/hr Head- 3654.47 m Tapping flow & press – 48.12 T/hr , 112.2 ksc BP inlet/outlet- 14/21 ksc , 186.2 ºC Shut off head- 4830m Rated motor power -11.5 MW Full travel time of scoop tube- 8 sec Critical speeds – 8548/10122 operating speeds-BP/MP- 1490/6275 Min R/C flow -220 T/hr Double piston balancing device with segmental tilting pad
thrust bearing
FST
BP
MAIN PUMP
Warm up line
From other BP’s
Boiler fill pump
sAmmonia.hydraineOxygen
RH spray Hdr BFP Dish Hdr
2nd stage
7th stage
Strainer cooling system
BFP warm up scheme
TDBFP
No of stages-7
Capacity- 1283.14 T/Hr
Tapping flow & press – 80.12 T/hr , 113.7 ksc
BP inlet/outlet- 14/28 ksc , 186.2 ºc
Total head- 3654 m
Rated speed MP/BP- 4678/2098
Rated power -13.5 MW
Min R/C flow -365 T/hr
Critical speed of MP- 6086/7621
TDBFP turbine
No of stages -09
Split casing design
Dual steam admission
Steam inlet – IPT-6th stage/ 21 ksc, 469 ºc.
Steam flow -61.4 T/hr
Operating speed- 4678 rpm
Critical speeds – 1899/6196 rpm
Throttle governing
01 stop valve & 02 control valves
HP HEATERS
HPH-6 HPH-7 HPH-8
Source of steam IPT- 3rd stage
CRH HPT – 13th stage
Inlet Press (ksc) & temp (ºC)
21
309
45.65
296
69.85
351
Quantity (T/HR) 41 93.18 79
Drip outlet temp (ºC) 200 223.64 265.42
Fw inlet /outlet temp 190/213 213/255 255/285
No of passes 03 03 03
HPH-6 & Its Desuperheater
TO HPH-7A
HPH-6
FROM BFP’s
TO DEA
FROM IPT-3rd STAGE
TO HPH-8 OUTLET
FROM HPH-8 OUTLET
22.7/224.5/231.3
373.6/196/1135
22.7/470/41.78
22.7/308/41.78373.6/215/1135
373.6/287.3/100
373.6/316/100
(Ksc/ºc/T/hrr)
CONDENSOR
DEAERATORCASCADE DRIP & VENT SYSTEM
HPH-8 HPH-7 HPH-6
HP bypass spray
100 % BYPASS
50% BYPASS
HPH-8A HPH-7A HPH-6A
To TDBFP AUX PRDS SPRAY
HPH-8A HPH-7A HPH-6A
ECO INLET
TO SH SPRAY
3-WAY VALVE
BFP dish header
TO DRAIN
BYPASS
TO BOILER
FROM BFP
HP HEATERS
Change over line
close
INITIAL FILL LINE
close
DRAIN LINE
BYPASS
TO BOILER
FROM BFP
HP HEATERS
DRAIN LINE
Change over line
close
open
INITIAL FILL LINE
HPH LEVEL HI-HI
MOT CentrifugeSelf cleaning type
Model: S 871Make: Alfa laval
Unit # 4 Overhauling
Overhaul was carried out by 5S- Individual almirah for individual bearings- Racks- Aluminium Boxes and trays- Tilting Drums for metallic and non metallic Scraps
Which saved valuable time in retrieval of spares and materials during box upand avoided un necessary mess up due to intermixing and loss of materials
Completed in 21 days and saved 3 days of original schedule
Thank you