April 10, 2023 1

POWER PLANT OPERATIONTURBINE &

AUXILIARIES

April 10, 2023 2

Presentation outline

CEP Starting

BFP Starting

Vacuum Pulling

HP, LP Bypass Charging

Turbine Rolling

April 10, 2023 3

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.

April 10, 2023 4

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.• CEP electrical supply is AVAILABLE.• Local operator intimated prior to starting of pump.

April 10, 2023 5

April 10, 2023 6

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.• All local line ups are COMPLETE

April 10, 2023 7

BOILER FEED PUMP

For starting first BFPChecks at LOCAL No maintenance staff is working. Check that De-aerator level is normal. 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 De-aerator 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 are OPEN. Check that drain valves are closed. Take out EPB of main pump and give clearance to UCB for starting.

April 10, 2023 8

BOILER FEED PUMP

For starting first BFPChecks at UCB No PTW is pending. Check feed pump gauges in UCB are in proper working order. 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. Check that the boiler requires feed water. Announce for feed pump starting &. ask local operator to be near

pump.

April 10, 2023 9

BOILER FEED PUMP

START BFP Check starting current and time. Check that recirculation valve opens and proper suction flow in

maintained. 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

April 10, 2023 10

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. • OPEN feed regulating station low range controllers isolating

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

requirement in the boiler.

April 10, 2023 11

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• START the BFP motor.• BFP scoop tube controller transfers to auto and follows master controller

output.• 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.

April 10, 2023 12

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%• 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.

April 10, 2023 13

VACUUM PULLING

• Ensure that BCW pumps are ON, BCW tank level is adequate and the air compressors are running

• SWITCH-ON SLCs of AOPs, JOPs, EOP, Gate valve gearing and the Lub. Oil temp controller.

• 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.• Turbine starts barring at 110 rpm approximately.• Lub oil temperature controller modulates to maintain set lub oil

temperature.• Start one CW pump

April 10, 2023 14

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 • At least one CEP is ON.• Main ejectors and GSC CHARGED from the waterside.• Condenser air valves to main ejectors are OPEN.

April 10, 2023 15

VACUUM PULLING

CHECK before starting vacuum pulling operation• Condenser vacuum breaker valve must be 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%.

April 10, 2023 16

VACUUM PULLING• 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 approx. 0.90 Kg/cm2

• Turbine barring speed increases up to 220-RPM approx.

• "Condenser vacuum low" alarm gets cleared off.

• ISOLATE starting ejector by closing air suction valve first and then steam supply valve.

• MAINTAIN rated condenser vacuum

• Condenser vacuum is maintained at approx. 0.9 Kg/cm2.

April 10, 2023 17

HP AND LP BYPASS CHARGING

CHECK before charging HP/LP bypass system

• MS pressure > 30 Kg/cm2, MS, CRH and HRH steam line drains are OPEN.

• Condenser vacuum is more than 0.8 kg/cm2• 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 OC approx. (for

cold start up)• HP bypass spray pressure set point: 70 Kg/cm2.• Open the HPBP downstream warm-up line valves.

April 10, 2023 18

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.• Open HP bypass valves (BP-1/BP-2) slowly while observing the Boiler

Drum level• CRH pressure starts increasing.• HP bypass temp controller and spray pressure controller transfer to auto

and maintain set values of downstream temp & spray pressure.

• LPBP water injection, Stop & Control valves will open as the re-heater

pressure rises.

April 10, 2023 19

CRITERIA FOR COLD WARM AND HOT START UP

15MW/M10MW/MIN5MW/MINLOAD GRADIENT

10 MIN15 MIN1HRSOAKING TIME

85 kg/cm2

485 ºC

60 kg/cm2

400 ºC

50 kg/cm2

350 ºC

ROLLING STEAM PARAMETER

MS Pr and Temp.

<8HR>48 HR>5 DAYSHUT DOWN TIME

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

HOTWARMCOLDPARAMETER

April 10, 2023 20

TURBINE START- UP

• CHECK that all the turbo-Supervisory instrumentations are functional. • All UCB indicators and recorders are functional and healthy.• CHECKS before starting the turbine run-up• 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.

April 10, 2023 21

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.• TSE influence is ON. • Unit trip relays 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.

Alarm Trip

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

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

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

April 10, 2023 22

TURBINE START- UP

• 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.

April 10, 2023 23

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 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.

April 10, 2023 24

TURBINE ROLLING

• Switch ON the ATRS programme• The various steps will get cleared as the criteria for the

steps get cleared according to the prevailing turbine component temperatures and the live steam conditions and other criteria as detailed in the ATRS programme logic diagram

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

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

April 10, 2023 25

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

April 10, 2023 26

MILESTONES DURINGTURBINE ROLLING PROCEDURE

• Starting device opens to 42% gradually.• Start-up oil pr. falls to 1.8 kg/cm2 and HP ESVs (1&2) open 100% at

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

of starting device.• Speed reference set point rises 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.

April 10, 2023 27

MILESTONES DURINGTURBINE ROLLING PROCEDURE

• 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 on 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.• Turbine speed reference set point rises to 3030 rpm.• Turbine EHC's output starts increasing slowly.• Turbine control valves (HPCV & IPCV) start opening more.

April 10, 2023 28

• 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.

MILESTONES DURINGTURBINE ROLLING PROCEDURE

April 10, 2023 29

MILESTONES DURINGTURBINE ROLLING PROCEDURE

• 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.

April 10, 2023 30

GRID FAILURE1.DC lighting ON

(Torch light must be available at least in night shift).

2. Ensure starting of emergency DC drives:

- DC Seal Oil pump of Generator

- DC EOP of main TG

- Scanner air fan

Then monitor battery voltage and current.

3. Ensure starting of air motors of APH’s.

4. Open vacuum breaker manually.

5. Close gland steam supply valve.

6. Ensure starting of DG set , charging of EMCC and then changing over of emergency drives.

7. If there is any delay/ problem in charging Emergency MCC from DG set, ensure hand cranking of barring gear.