New features of 660 MW Units Turbine Maintenance Sipat Super thermal - - PowerPoint PPT Presentation

New 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-660-247 Four Cylinder, tandem compound, Reheat, Condensing Turbine Spring 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

Governing Box HP Turbine IP Turbine LP Turbine # 1 LP Turbine # 2 MS CRH HRH HPH#8A HPH#7A HPH#6A CRH LPH#4 LPH#3 LPH#2 LPH#1 LPH#1 Deareator HPH#8B HPH#7B HPH#6B Steam cooler HPH#8A HPH#7A HPH#6A LPH#4 LPH#3 LPH#2 LPH#1b LPH#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 parameters

Parameters 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 parameters

Locations Pressure (bar) – Absolute Temperatures (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
• f 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 GENERATOR ECT M

M

COOLER A COOLER B DUPLEX FILTER A DUPLEX FILTER B DMCW O/L DMCW INLET HPC IPC LPC1 LPC2 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

FROM SEAL OIL SYSTEM FROM PURIFIER UNIT TO SEAL OIL SYSTEM TO PURIFIER UNIT TO EOT TO JACKING OIL SYSTEM 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 HPC LPC 1 IPC LPC 2 BRG2 BRG3 BRG4 BRG5 BRG6 BRG7 BRG8 BRG9 BRG10

FROM MOT

H= 120 ksc

r

Rotor

Rotor Jacking oil Oil outlet points Oil inlet from JOP discharge header

TG ROTOR JACKING OIL SYSTEM

ROTOR JOP(AC) PROTECTIONS & INTERLOCKS

• Rotor oil jacking pump (AC) starts automatically if
• Speed becomes lower than 800 rpm(but not zero i.e >3 rpm) &
• Vacuum breaking valves are closed
• Rotor oil jacking pump (AC) stops automatically if
• Speed becomes higher than 1200 rpm (OR)
• Oil Pr at p/p suction decreases down to L=0.8 ksc (OR)
• After pump start oil pressure in the discharge header < LL=20 ksc

(Td=60 sec).

• 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

• Oil pressure in the rotor discharge jacking oil header < 45 ksc.&
• Speed becomes lower than 800 rpm(but not zero) &
• Vacuum breaking valves are closed &
• Turbine stop valves are closed

Rotor oil jacking pump (DC) stops automatically if

• 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.

 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 HPC LPC 1 IPC LPC 2 BRG2 BRG3 BRG4 BRG6 BEARING HOUSING ORIFICE BRG5 BRG7 BRG8 BRG9 BRG10

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.

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. LINE NON-STABILIZED

• PR. LINE

ACCUMULATOR TO DRAIN HEADER 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 VALVE

LEVER

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.

INTERMEDIATE SHAFT

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 1

With manual trip button

Trip Solenoid 2

With 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

• il above

piston Tie rods Pilot v/v

HP STOP VALVE IP STOP VALVE

Head oil I/L Drain port Control

• il I/L

Head oil I/L CAM ATT 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

• peration of EHC.
• For ‘0’ signal from Turbine controller
• utput pressure is equal to 0, because
• f draining.
• Output pressure signal also goes for
• pening 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

• peration of solenoid protection valves during turbine
• peration.

– 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 Curve

Speed 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 – 8H

3 - 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

Recirculatio n to Condenser

HOTWELL 1 HOTWELL 2

CEP-A CEP-C CEP-B

CPU GSC

LPH1.1 LPH1.2 LPH 2 LPH 3 LPH 4

DEAERATOR

DRIP P/P-A DRIP P/P-B CEP-A DRIP P/P-A DRIP P/P-A DRIP 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

• ther

BP’s Boiler fill pump s Ammonia. hydraine Oxygen 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 22.7/308/41.78 373.6/215/1135 373.6/287.3/100 373.6/316/100 (Ksc/ºc/T/hrr)

CONDENSOR DEAERATOR CASCADE 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

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INITIAL FILL LINE

HPH LEVEL HI-HI

MOT Centrifuge

Self cleaning type Model: S 871 Make: 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 up and 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