Turbine Operation

April 8, 2023 H K Sethi 1

POWER PLANT OPERATIONTURBINE &

AUXILIARIES


Presentation outline

CEP Starting

BFP Starting

VACUUM PULLING

HP, LP BYPASS CHARGING

TURBINE ROLLING


CEPFor starting first CEPChecks at LOCAL No maintenance staff is working.• CEP suction valves are OPEN.• Hot well level is ADEQUATE • Bearing temperature of CEPs is NOT HIGH 60 0 C.• Condensate pump gland sealing water isolating valve is OPEN.• Condensate pump priming (pressure equalizing) valve is OPEN.• CEP bearing cooling water line isolating valve is OPEN.• CEP bearing oil level is adequate.• Emergency push button is released.• ENSURE condensate system is lined up before starting CEP.• Main ejectors inlet/outlet- valves are OPEN & Bypass valve is closed. • Gland steam cooler inlet/outlet valves are open and bypass valve is

CLOSED.• LPHs (1-2-3) inlet/outlet valves are CLOSED.• LPHs (1-2-3) bypass valves are OPEN.• LPHs are bypassed initially to minimise corrosion.


CEP START the CEP motor.• CEP starting current comes down to 20A after 5 sec.• CEP discharge pressure increases to 25 Kg/cm2. Approx. • CEP's discharge valves open 100%.• CLOSE the air vents on condensate lines. • LOAD the condensate pump by opening V/V on condensate to D/A line.• INSTRUCT the local operator to check bearing temperatures and

vibrations.• CHECK that the second condensate pump is ready for starting and is

available on STANDBY.• Breaker control switch is on Normal • Pump OK standby - All permissive are SATISFIED.• All local line ups are COMPLETE


CEPFor starting first CEP

Checks at UCB

• CHECK if all start permissive for starting CEP is satisfied.• Hot well level is ADEQUATE (UCB Indicator).• Bearing temperature of CEPs is NOT HIGH 60 0 C.) UCB indications. • CEP re-circulation valve is OPEN.• Hotwell level controller output is zero.• CEP electrical supply is AVAILABLE.• Deaerator inlet valve is OPEN.• CEP header vents and line vents OPEN.• HW level controller, DA level controller and cycle make-up controller

valves are CLOSED. • Bypass valves of HW, DA and cycle make-up controllers are also

CLOSED.• Local operator intimated prior to starting of pump.


BOILER FEED PUMPFor starting first BFPChecks at LOCAL No maintenance staff is working. All control and measuring instruments are in place. Check availability of compressed air for pneumatically operated valves. Check that Deaerator level is normal. Make local check and confirm by

draining the gauge glass and recharging it. BFP suction v/v is fully open. BFP booster pump suction pressure is ADEQUATE (>3.0 KSC).• BFP motor air box cooling water-inlet/ outlet manual valves are OPEN.• BFP suction strainer DP is not more than 0.2 Kg/cm2 BFP manual re-circulation valves at the Deaerator are 100% OPEN. Check that oil level in lub. oil tank is normal. Take out EPB of auxiliary lub. oil pump. Confirm that it starts and develops

required lub. oil pressure. Check lub. oil flow through drain line is normal. Check that both lub. oil and working oil coolers are charged from water as well as oil side.

Check BFP discharge valve & its bypass valve is closed. All air vents on suction and discharge lines of BFP and feed regulating station

are OPEN. Check that drain valves are closed. Take out EPB of main pump and give clearance to UCB for starting.


BOILER FEED PUMPFor starting first BFPChecks at UCB No PTW is pending. Check feed pump gauges in UCB are in proper working order. Check all remote operated valves have been given power supply &

confirm their proper operation with local operator. Check D/A level is normal. Check lub. oil pressure is O.K. Check all the protection and interlocks of the pump have been

checked and found O.K. Check feed water line has been properly lined up.• Feed regulating station control valve are in CLOSED position. Check the valve indications (OPEN/CLOSE) are O.K. BFP pneumatic recirculation valve is 100% OPEN. Check scoop tube is in minimum position. Get electrical supply for the pump. Check all the flag relay provided for the pump are reset. Check that the boiler requires feed water. Announce for feed pump starting &. ask local operator to be near

pump.


BOILER FEED PUMPSTART BFP Check starting current and time. Check that recirculation valve opens and proper suction flow in

maintained. Check electrically operated cooling water valve opens & proper

cooling water flow is established. Check warm up valve has closed. Check auxiliary lub. oil pump has stopped. Check feed pump vibration are normal (local check) Check balancing leak off’ chamber pressure is normal. Check bearing temperatures of main pump, motor and hydraulic

coupling bearings are normal. INSTRUCT Local operator to check bearing vibration and

temperatures locally Command is given for opening of main pump discharge valve

first integral bypass v/v Opens and their after main v/v opens up. the feed pump

Suction flow increases to 150 T/Hr. approximately.


BOILER FEED PUMP RAISE BFP scoop tube position to get desired feed water. BFP discharge pressure rises. If on auto BFP scoop tube can be

operated through BFP master. Re-circulation valve auto release becomes available, if BFP flow

exceeds 150 T/Hr.• OPEN feed regulating station low range controllers isolating

valves.• Open feed regulating station control valves as per the feed water

requirement in the boiler.


BOILER FEED PUMP• WHEN ONE PUMP IS RUNNING• CHECKS before starting the second BFP.• All pre-start checks are OVER.• All BFP start Permissive is AVAILABLE.• BFP main discharge valve OPEN.• Aux. oil pump is ON and lub oil pressure is ADEQUATE.• BFP scoop tube position is MINIMUM• BFP selector switch is on NORMAL.• START the BFP motor.• BFP scoop tube controller transfers to auto and follows master controller

output.• Motorised cooling water valve, open up.• BFP aux. oil pump trips automatically as the main oil pump takes over.• Re-circulation flow control transfers to auto.• ADJUST scoops of the two running BFPs to equalise loads.• ADJUST BFP bias to 50% and ADJUST BFP master controller equal to

BFPs scoop tube position.• TRANSFER running BFP SCOOP control to auto.


BOILER FEED PUMP• BFP SHUTDOWN PROCEDURE• TRANSFER scoop control of the BFP to manual.• BFP master also transfers to manual.• REDUCE scoop tube controller of the BFP to minimum

position.• BFP discharge pressure and flow start decreasing• STOP the BFP motor.• BFP motor breaker opens. • BFP re-circulation valve opens 100%• Motorised cooling water valve starts closing.• If no other BFP is in service the discharge valves of all BFPs

start closing.• Close the BFP suction valve and rack out breaker if any

maintenance to be carried out.


VACUUM PULLING• CHECK before starting vacuum pulling operation.• Auxiliary steam header charged and its pressure

ADEQUATE.• Ejector PRDS is CHARGED and Ejector steam pressure is

ADEQUATE ( 7.5 Kg/cm2)• At least one condensate pump is ON.• Main ejectors and GSC CHARGED from the waterside.• Condenser air valve air valves to main ejectors are OPEN.


VACUUM PULLING• CHECK before starting vacuum pulling operation.

• Surge tank level ADEQUATE. • Condenser siphon filling COMPLETED.• Condenser vacuum breaker valve must be CLOSED. Water

sealing done.• Condenser inlet & outlet valves are CLOSED.• Steam line drains to flash tank, are CLOSED• MOT level is NORMAL and "MOT level low" alarm is

RESET.• At least one MOT vapour extractor fan is ON.• Generator hydrogen pressure must be 3.5 Kg/cm2.• Generator hydrogen purity > 97%.


VACUUM PULLING• CHECK before starting vacuum pulling operation.

• Hydrogen seal oil pressure should be more than 4.8 Kg/cm2.

• Seal oil to hydrogen DP is ADEQUATE, 1.2-1.5 kg/cm2.

• START AOP and one JOP.• "Control oil pressure low" and "Lub. Oil pressure

low" alarms get cleared off.• Control oil pressure increases to 6.8 Kg/cm2.• Jack oil pressure increases up to 130 Kg/cm2.

"Jacking oil pressure low" alarm clears off.


VACUUM PULLING• SWITCH-ON SLCs of AOPs, JOPs, EOP, Gate valve

gearing and the Lub. Oil temp controller.• Turbine starts barring at 110 rpm approximately.• Lub oil temperature controller modulates to maintain set lub

oil temperature.• CHARGE condenser priming ejector from steam & airside.

Condenser water box priming initiated.• INSTRUCT local operator to start one CW pump and

CHARGE both condensers 50 % approx., to curb CW power consumption.

• CW header pressure increases, slightly.• Condenser inlet & outlet valves are partially opened.• Condenser flow starts increasing.


VACUUM PULLING• CUTOUT the priming ejector after CW water starts coming from the air

vents of priming ejector.• Priming ejector's steam airside valves are closed.• OPEN seal steam line and header drains & CHARGE gland sealing

steam into the turbine glands.• Gland seal steam control opens up and gland steam header pressure

starts increasing.• TRANSFER seal steam control to auto.• CHARGE starting ejector by opening ejector’s steam supply & air

suction valve.• Condenser vacuum starts increasing to 0.7 Kg/cm2.• OPEN steam supply valve to any one main ejector as per desired

vacuum.• Vacuum builds up to 0.92 Kg/cm2 i.e 72 mm Hg (approx)• Turbine barring speed increases up to 220-RPM approx.• "Condenser vacuum low" alarm gets cleared off.


VACUUM PULLING• ISOLATE starting ejector by closing air suction

valve first and then steam supply valve.• MAINTAIN rated condenser vacuum of 73 mm Hg

(back pressure) • Condenser vacuum is maintained at 0.92 Kg/cm2.


HP AND LP BYPASS CHARGINGCHECK before charging HP/LP bypass system.

• M S pressure 12 Kg/cm2 CRH and HRH steam line drains are OPEN.

• HP bypass oil unit's oil level NORMAL, its Pump ON and its pressure ADEQUATE.

• LP bypass rack is LINED UP and all setting & tripping values checked.

• HP bypass downstream temperature set point is at 200 O C approx.

• HP bypass spray pressure set point: 70 Kg/cm2.• All isolating valves before the spray pressure controller are

OPEN.• HP bypass upstream• pressure (main steam pressure) set point is at 10 Kg/cm2.


HP AND LP BYPASS CHARGING• TRANSFER LP bypass control to auto and SWITCHON the Automatic

Control Interface (ACI).• HRH fixed set point comes to 3 Kg/cm2.• TRANSFER HP BP control to auto.• HP bypass valves (BP-1/BP-2) start opening if MS pr. is more than the

set point.• CRH pressure starts increasing.• HP bypass temp controller and spray pressure controller transfer to auto

and maintain set values of downstream temp & spray pressure.

• ADJUST main steam pressure set point to obtain desired MS pressure.

• HP bypass valves open or close, depending on whether set point is less or more than the MS pressure respectively.


CRITERIA FOR COLD WARM AND HOT STAR UP

15MW/M10MW/MIN5MW/MINLOAD GRADIENT

10 MIN15 MIN1HRSOAKING TIME

85KSC

485C

60 KSC 400C50KSC 350CROLLING STEAM PARAMETER

MS Pr and Temp.

<8HR>48 HR>5 DAYSHUT DOWN TIME

>350150-350<150HPC/HPS TEMP 0 C

HOTWARMCOLDPARAMETER


TURBINE START- UP• CHECK that all the turbo-Supervisory instrumentations are

functional. • All UCB indicators and recorders are functional and healthy.• All recorders are inked and all instruments are calibrated.• CHECKS before starting the turbine run-up• Electro-hydraulic controller for turbine is ON.• EHC isolating valves on sec oil lines to control valves are

open.• Electro-hydraulic controller's output is zero.• "EHC control fault" and "EHC Plunger coil off" alarms do not

appear in the UCB.• Speed reference set point for the Speed Controller is zero or

less than the barring speed.


TURBINE START- UP• Load reference set point for the Load Controller and the

load limiter output are zero.• Speeder gear position is 100%.• Starting device is at 0% position.• The alarms "TSE influence off" "Turbine stress effects off"

and "Turbine stress cubicle fault" are not on.• TSE influence is ON. • Unit trip relay (A & B) are in RESET condition• "Turbine Trip" and "Turbine Trip gear operated" alarms are

not on and Trip oil pressure > 5 Kg/cm2

• All differential expansions of the turbine are NORMAL and within the alarms values.


TURBINE START- UPAlarm Trip

HPT +4.5mm +5.5mm-2.5mm -3.5mm

IPT +5.0mm +6.0mm-2.0mm -3.0mm

LPT +25 mm +30 mm- 5 mm - 7mm

• Condenser vacuum is NORMAL. 0.92 Kg/cm2 approx.• Turbine SLC Drains is ON and NOT FAULTED. "SLC Drains fault" Alarm is not

ON.• Turbine stop valves (ESV-1&2, IV-1&2). Control valves (HPCV-1&2), IPCV- 1&2).

Extraction block valves (ES-1,2,3,7,5,6) are CLOSED.• Extraction NRV's (A2, A3,A4, A5) and CRH line NRV's L/R are CLOSED.• The turbine is on BARRING and there is no abnormal sound from the turbine &

bearings.• The Speed of rotation of shaft is between 200 and 220 rpm.• Turbine "Control oil pressure" is greater than 5 Kg/cm2• Turbine lub oil temperature after coolers is normal i.e. 45oC. • Lub oil pr. is normal at 3.5 Kg/cm2 before coolers.• Main oil tank level is NORMAL.• Thrust bearing oil filters are NOT CHOKED.


TURBINE START- UP• CHECK that the entire turbine MS strainer drains CRH drains HRH

strainer drains and ESV & IV before seat drains are open.• CHECK that the generator seal oil and stator water system are in

service and healthy Generator hydrogen pressure is NORMAL, more than 3 Kg/cm2 Seal oil pressure (turbine and exciter side) is more than 4.8 Kg/cm2 Seal oil to hydrogen DP is NORMAL (1.2 Kg/cm2) Stator water flow is more than 23 m3/Hr. Stator water specific conductivity is less than 1 micro mho/cm. Stator water pressure is NORMAL. (2.8 Kg/cm2) Generator and field breakers are in RESET condition.


TURBINE START- UP• TURBINE ROLLING PROCEDURE• CHECK turbine startup criteria as determined from the X-curves.• Main steam, at the turbine inlet should have minimum of 50 oC superheat.• M.S. pressure is 30 KSC approx. & temp. 280oC Criteria for Opening the

ESVs. • Max/Min. SH steam temp depending upon mid wall temp. of HPCV. (Start-

up curves X- 1, X-2 and X-3.)• Rolling to warm-up speed of 600 rpm. Max. MS temp depending upon

saturated steam temp and mid body temperature of HP casing/ shaft. (Start-up curves X-4 and X- 5.)

• Rolling up to rated speed of 3000 rpm.• Required minimum mean metal temp of H.P Shaft depending upon available

MS temp. (Start-up curve X-6)• Loading the turbine after synchronisation.• Required minimum mean metal temp of IP shaft, depending upon the

available HRH steam temp. (Start-up curve X-7)


CRITERIA CURVE X1,X2,X3,X4,X5

• X1 CURVE IS STEAM TEMP BEFORE HPBYPASS/MIDWALL HPCV

• X2 CURVE IS MAIN STEAM TEMP BEFORE HPCV/MIDWALL HPCV

• X3 CURVE IS STEAM TEMP BEFORE HPCV/ MAINSTEAM

SATURATION TEMP

• X4 CURVE IS MAIN STEAM TEMP BEFORE HPESV/MIDWALL

HPCASING

• X5 CURVE IS HRH TEMP BEFORE LP BYPASS/MIDWALL IP SHAFT

• X6 CURVE IS MAIN STEAM TEMP BEFORE HP BYPASS/MIDWALL

HPCASING

• X7 CURVE IS HRH TEMP BEFORE LP BYPASS/MIDWALL IP CASING


DESCRIPTION UNIT HP HEATER IN

NCR 210 MW

SAT STEAM TEMP. IN DRUM °C 348

STEAM TEMPERATURE AT LTSH OUTLET °C 400

STEAM TEMPERATURE AT SH PLATEN OUTLET °C 510

STEAM TEMPERATURE AT FINAL SH OUTLET °C 540

STEAM TEMP. AT RH INLET °C 337

STEAM TEMP. AT RH OUTLET °C 540

WATER TEMP. AT ECO INLET °C 244

WATER TEMP. AT ECO OUTLET °C 274

AMBIENT AIR TEMPERATURE °C 35

AIR TEMPERATURE AT AH OUTLET (PRI. SIDE) °C 354

AIR TEMPERATURE AT AH OUTLET (SEC. SIDE) °C 348

FLUE GAS TEMPERATURE AT SH PLATEN INLET °C 1165

FLUE GAS TEMPERATURE AT RH FRONT INLET °C 1016

FLUE GAS TEMPERATURE AT RH REAR INLET °C 868

FLUE GAS TEMPERATURE AT SH FINISH INLET °C 753

FLUE GAS TEMPERATURE AT LTSH INLET °C 638

FLUE GAS TEMPERATURE AT ECO INLET °C 473

FLUE GAS TEMPERATURE AT AH INLET °C 379

FLUE GAS TEMPERATURE AT AH OUTLET °C 146


TURBINE ROLLING PROCEDURE

• Maintain boiler side steam parameters as required for turbine start-up.

• The MS/HRH temp and pressures are within the determined ranges.

• HRH steam pressure should not be more than 15 Kg/cm2 during rolling.

• RAISE starting device to 70% gradually.• Start-up oil pr. Falls to 1.8 KSC and HP ESVs (1&2)

open 100% at 42% position of starting device.• Interceptor stop valves (1&2), open 100% at 56%

position of starting device.• Start-up oil pre. = 0 at 70% of starting device position.

Aux Sec oil pressure increases up to 4 KSC.



• SWITCH ON SLC "Warm-up controller“ is required (during cold rolling)• Drains before HP control valves, (HPCV-1/2), start opening, 100%.• HP ESVs and control valves, heating starts and their respective temp.

start increasing. • Surface and mean temp start rising.• Wait until the mean temperatures of HPCVs come to min. 200 - 250 oC. • Min. temp requirement for HPSV/HPCV is only for absolute cold

startups • Upper TSCmargin for admission channel starts droping slowly & after

minimum temp are attained, starts improving again.• Maintain all TSE margins of Admission channel > 30 K.• The metal temperatures of ESV/CV body are within 30oC of the MS

temp preferably.• The heating-up of stop/control valves is complete.• RAISE speed reference set point to 600 rpm.• EHC starts increasing from its initial zero position.• Speed controller is in action during turbine rolling.



• HP CVs start opening.• Turbine speed starts rising to 600 rpm at a rate selected by TSE.• The gate valve for turbine barring starts closing when turbine speed

comes to 240 rpm. "Gate valve gearing not closed" alarm starts flashing and resets after the valve gets fully closed.

• The JOP trips in auto as the turbine speed comes to 540 rpm.• MAINTAIN turbine speed and soak till required HP shaft temp is

attained.• DT (MS temp. – Mean HP shaft temp) becomes less than the value

specified by turbine start-up curve X-6.• Maintain all TSE margins more than 30 K.• RAISE turbine speed reference set point to 3030 rpm.• Turbine EHC's output starts increasing slowly.• Turbine control valves (HPCV & IPCV) start opening more.


• Turbine speed starts increasing gradually at a rate decided by turbine stress evaluator.

• Ensure TSE margins to ensure a min. speed gradient of > 108 rpm /minute to avoid DN/DT protection.

• Critical speeds 1370, 1544, 2125 RPM • "Turbine/Gen. bearing vibration high" and "Turbine absolute shaft

vibration high" alarms flash when turbine speed crosses 1400 rpm and 2200 rpm

• (approx.) and vibration levels increase appreciably and again become normal.

• Bearing temperatures display an upward trend If vibrations are already on higher side before the critical speeds, DO NOT ROLL and soak at 600 for some more time until vibrations become normal.

• MAINTAIN turbine speed. • Soak until required IP shaft temp is reached and SET load reference at

20-40 MW (to ensure speed controller transfers to load controller after• Synchronising). Load limiter set point must be more than load ref.• Load gradient at 10 MW /Minute (Max) Load controller is set at 20-40

MW.



• DT (HRH steam temp- Mean IPS temp) becomes less than the value specified by turbine startup curve X-7.

• CHECK all the turbine / generator parameters before synchronisation.• All bearing pedestal vibration is less than 35 microns.• All relative shaft vibrations are less than 150 microns• All bearing babbit metal temp are less than 80 oC• Bearing return oil flow is normal and temp < 77 oC.• All casing absolute expansions are within normal range. HPT - < 15 mm.

IPT - < 10 mm.• Thrust bearing oil filters are clean (not choked).• Axial shift < + 0.3 mm.• Turbine casing top/ bottom temperature is< 30 oC.• Condenser vacuum is normal at 0.92 Kg/cm2• Gen hydrogen pressure is normal at 3.5 KSC• Stator water flow is More than 27 m3/Hr.• Stator water specific conductivity is less than 5 micro mho/cm.• Seal oil to hydrogen DP is normal (1.2-1.50 Kg/cm2).



THANK YOU

Turbine Operation

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