Turbine Start-Up

1. TURBINE START-UP
Presented By:
M.V.Pande
Dy.Director

2. General Operation Philosophy
➢Achieving and maintaining the required output of the unit
➢Maintaining plant conditions at their optimum efficiency
➢Inspection for plant deterioration by studying the operation trends of main
equipments and their auxiliaries (condition monitoring). The maintenance
logs can be generated from this information.
➢T
esting of stand-by plant auxiliaries, protective devices, alarms and
automatic cut-in feature.
➢Changing over of auxiliaries depending on their running hours.
➢Generation of shift logs, event logs, post trip logs etc.
➢Readiness to respond to abnormal conditions.

3. General Preparation for Start-up
• It should be ensured that all the repair works on turbine
system have been completed and all the permits are
are healthy and in
cancelled ensuring that equipments
operative condition
• First of all bring all the electrical equipments to a state of
readiness i.e., switch-on the necessary switchgear for
motors, valve actuators, controls protections and monitoring
system
• After this, carry out the necessary interlocks and protection
checks feasible under stationary condition of turbine.
Certain tests and checks require bypassing of certain
interlocks. All such deliberate bypassing of interlocks must
be prominently displayed in the control room during the test.
After the test, all interlocks and protections should be
brought to normal state

4. General Preparation for Start-up
• Various valves as per the scheme are to be kept in open
or close position. It must be ensured that these valves are
kept up in the required position. The isolating valves for all
measuring control and protective device should be kept in
fully open position
• Turbine oil quality should be checked for viscosity,
neutralization number, sludges etc. If required, the oil
should be drained from MOT and topped up with fresh oil
in order to restore the quality
• Condenser tube leakage should be checked by charging
the CW system and watching the increase in hot well
level. If good amount of leakage is noticed, then action
must be taken to plug the leaking tubes

5. Turbine Start-up Requirements
Turbine start-ups are classified as cold start-up, warm start-up and hot
start-up depending on the HP turbine metal temperature as follows:
If HPT metal temperature >350oC -Hot start-up
If HPT metal temperature between 150 - 350oC -Warm start-up If
HPT metal temperature < 150oC -Cold start-up
The start-up procedure decides following aspects:
• i) Steam parameters suitability viz. pressure and temperature & its
raising rates.
• ii) Soaking time for turbine and main valves
• iii) Turbine speed raising, loading rates
• iv) T
otal time required reaching the full load.

6. Turbine Start-up Requirements
❖ Generally absolute cold start-up of turbine takes 6 hours to
reach the full load
❖ The turbine after two hours shutdown may require only
half an hour to one hour to reach the full load (depending
on boiler load)
❖ The rate of rise of steam parameters and turbine
parameters, (speed, load) are specified by start-up curves
for the regime. Operators should provide necessary time
for proper soaking of turbine at specified speeds (600 and
3000 rpm), as shown by the curves, for permitting
expansions at normal rate. This will give good temperature
& load margins after synchronization

7. Cold Start-up Steps
1. Pre-start checks and testing of supplies
2. Establishing lube oil and jacking oil system
3. Putting turbine on barring gear
4. Warming of main steam pipe lines (steam line drains
and turbine SLC drains must be kept open)
5. Pulling-up vacuum in condenser by starting ejector
6. Establishing turbine gland sealing (at about 0.2
kg/cm2 vacuum)
7. Putting main ejector into service (at about 0.7 – 0.8
kg/cm2 vacuum) and withdrawing starting ejector.
Normal vacuum of 0.91 kg/cm2 is obtained.
8. Charging of reheater through HP-LP Bypass system
9. Building of steam parameters suitable to turbine
condition, viz. for cold start-up parameters are as
follows:

8. Cold Start-up Steps
M.S. H.R.H.
Pressure 30- 35 kg/cm2
T
emperature 320o – 350oC
Flow 95 –100 t/hr
10-12 kc/cm2
320o – 350oC
10. Warm-up of turbine stop valves (ESV & IV) to get the TSE
margins >30oK & fulfillment of steam pressure and
temperature criteria (X1, X2,X3)
11. Turbine trip resetting by bringing S.L.L.D. to zero
position.
12.Opening of stop valves (ESV & IV) by raising the SLLD
(starting device) to 42% and 56% respectively
13. Warming of HP control valves by opening warm-up
control drains valves through warm-up controller

9. Cold Start-up Steps
14. Fulfillment of steam temperature criteria with respect to mid wall
temperature of turbine metal to ensure that main steam temperature is
greater than turbine metal temperature & degree of superheat is >
50oC as recommended by criteria curves X4 and X5 respectively. TSE
margins are ensured greater than 35oK
15. Preparing the electro-hydraulic governing system ready for operation
by setting the speed & load controller reference values & keeping
hydraulic governor as back-up by raising speeder gear position to
100%
16. Turbine rolling to 600 rpm through speed controller
17. Soaking of turbine at 600 rpm to fulfilled X6 criterion (approx. 1 hr),
which ensures the proper warming of HP turbine with respect to main
steam temperature. Turbine parameters monitoring
18. Speed raising to 3000 rpm by setting speed reference value at 3000
rpm without stopping in between

10. X5 Criterion- M.S. Temperature

11. X5 Criterion- H.R.H. Temperature

12. Cold Start-up Steps
19.Soaking of turbine at 3000 rpm to fulfilled X7 criterion (approx. 45
min.), which ensures proper warming of IP turbine with respect to
HRH temperature. Monitoring turbine expansion and shaft/bearing
vibration trend
20.Ensuring TSE upper temperature margin of turbine greater than
35oK
21. Synchronization of generator to grid
22. Load raising to 10% (20MW) through speed reference setter.
23. Closing of all manual operated drains
24.Ensuring closure of HP-LP bypass valves by increasing pressure
set point above M.S. pressure
25. Check that load controller becomes active at about 20 MW.
26. Raising the M.S. pr. to 50 kg/cm2 by taking coal mill into service
and load is raised to 40 MW
27.Charging of LP heaters from steam side and putting the level
controllers of LPH 2 & 3 on auto

13. Cold Start-up Steps
28. T
aking second coal mill into service and raising steam pressure. Ensure
that HP bypass set point is kept at higher value than actual pressure
29.Raise the turbogenerator load to 100 MW. T
ake HP heaters into service.
30.Establish second air cycle, second BFP
, third coal mill and raise the
steam parameters
31.Changing over the deaerator pegging steam supply from CRH to
extraction-4 at about 55% load (when the NRVs release is obtained).
32.Raising the load to 150 MW
33. T
aking the fourth coal mill into service. Put at least two mills on Auto.
Stabilize the M.S. pressure at about 140 kg/cm2
34.Putting CMC in to service after adjusting the M.S. Pressure set point to
match with actual pressure
35.Raising the turbogenerator load to 210 MW through unit target load set
point at CMC
36.Monitoring of turbovisory parameters, viz. absolute expansion, differential
expansions, axial shift, bearing & shaft vibrations, casing temperatures at
admission and exhaust locations, bearing temperatures

14. Turbine Oil System
Check that:
➢ MOT level is normal ( 0+350 mm ) and basket
strainers are cleaned
➢ Fire protection shut-off valve is closed and solenoid is
reset at turbine floor and in MOT room.
➢ Readiness of Lube oil pumps and JOPs
➢ Sub-group control of oil system "Auto-ON"
➢ Ensure one of the lube oil coolers is in service from
oil side and water side.

15. Turbine Oil System

16. Turbine Oil System

17. Turbine Oil System
Operation :
• AOP and JOP can be started manually from PCR or on auto
through “SLC-ON” or through SGC "Auto-ON"
• T
ake the standby trial of AOP
, EOP and JOP
• Watch drop in MOT level after AOP is started (280 mm).
• Put temperature controller SLC "ON"
• Watch the oil temperature at oil cooler outlet and ensure that it is
maintains between 40o – 45oC by temperature controller
Watch following parameters :
-Discharge pressure of AOP : 6.5 kg/cm2
i)
ii)
iii)
-Oil Pressure before cooler
-Oil pressure after cooler
:
:
5.4 kg/cm2
4.8 kg/cm2
-MOT level
-Jacking Oil Pressure
:
:
+ 25 mm
120 kg/cm2

18. Turbine Oil System
When the turbine is running, check the bearing drain oil temperature and
babbit temperatures :
• Bearing drain oil temperature :
• Journal bearing babbit temperature :
• Thrust bearing babbit temperature :
•
•
•
•
•
•
•
•
•
•
•
< 60oC
< 90oC
< 110oC
Permissives for starting turning gear :
Seal oil to H2 DP
Seal oil pressure TE & EE
H2 gas pressure
H2 purity
Liquid in generator
:
:
:
:
:
> 1 kg/cm2
> 4.4 kg/cm2
> 3.3 kg/cm2
> 97%
Not present
Turning gear can be started by opening gate valve either manually or
through SLC. Observe that turbine speed on turning gear is as follows :
When no vacuum in condenser
At normal vacuum condition
:
:
110 – 120 rpm
150 – 160 rpm

19. Turbine Oil System
After turning gear is ON,AOP amperes will increase to 125Afrom 105A.
AOP
, JOP and turning gear trip and pick-up speeds are as follows :
➢ When MOP takes over, the discharge oil pressure will be 8.5 – 9.5
kg/cm2 depending on turbine speed.
➢ Interlocks ofAOP
, EOP & JOP
➢ The standby AOP (SLC ON) will pick-up if discharge oil pressure < 4.8
kg/cm2 or the runningAOP is OFF
➢ DC Emergency Oil Pump will pick-up when SLC is ON and if lube oil
pressure is < 1.1 kg/cm2
➢ The standby JOP (SLC ON) will pick-up if running JOP trips.
Trip Speed rpm Pick-up Spee
rpm
i) Turning gear 240 210
ii) J.O.P. 540 510
iii) A.O.P. 2850 2800

20. Condensate & Feedwater Line Charging

21. Vacuum Pulling and Gland Sealing Checks
• Line-up the steam ejectors
• Ensure 220 V DC supply to the solenoid of vacuum breaker
valve and it is closed
• Ensure water sealing to glands of all the valves in vacuum
circuit
• CW system is established
• Condensate system is established
• Ensure gland steam cooler siphone is filled-up
• Ensure electrical supply to the motors of seal steam leak-off
controller and seal steam supply controller. Their oil pumps
are working on auto to maintain oil pressure of 60 kg/cm2
• Check that valve AS301 (CRH Steam to glands) is in closed
position
• The turbine is put on turning gear

22. Vacuum Pulling and Gland Sealing

23. Vacuum Pulling and Gland Sealing Operation
• Charge the gland steam header by opening AS 378 valve and build up
the pressure 6 –6. 5 kg/cm2. Set the pressure 6.5 kg/cm2 and put the
ejector steam pressure control on auto.
• Start vacuum pulling through starting ejector by first opening steam
valve and then the air valve.
• Start one exhauster fan of gland steam cooler
• After building up 0.2 kg/cm2 vacuum, open the gland seal steam supply
valve and charge the header at pressure 0.01 kg/cm2(g).
steam pressure control on auto.
• After opening the steam supply valve, the header drain valve MAL-81
will close on auto.
• After establishing the gland sealing, the condenser vacuum will improve
at a faster rate
• When vacuum builds-up to 0.7 kg/cm2, take one main ejector in to
service by opening first its steam valve (AS02 or AS03) and then the air
Put the gland
valve. Cut-off the starting ejector by closing air valve and then steam
valve.
• Note the final value of vacuum at which it stabilizes (0.92 kg/cm2) and
also note HPT/IPT & LPT differential expansions

24. Warming of Steam Piping
Checks :
➢Ensure all the drain valves M.S., CRH and HRH lines are open
➢M.S. line to be charged when drum pressure is raised to
10 kg/cm2 after blow-down
Operation :
❖ Charge the M.S. line by opening the boiler outlet bypass valves
(MS 301A/302A)
❖ Ensure that there is no hammering in M.S. pipeline
❖ Watch the temperature rise of ESV mid wall
❖ Rate of heating of steam pipelines should not exceed 25o to 30oC
per 5 min.
❖ During heating of M.S. & R.H. steam pipelines; the temperature
difference between LHS & RHS pipelines should not exceed
15oC. But this difference should not exceed 10oC when the set is
on load

25. HP-LP Bypass System Charging
Checks :
• Ensure that HP Bypass control oil pumps are running on auto and
maintaining the pressure oil pressure 110 kg/cm2 and oil tank level is
normal
• All the oil supply/return/leak-off Sulzer valves are open and there is no oil
leakage in the system
• ESV and IVs are closed
• Cooling water to HP BP valve gland from CEP is open
• Isolating spray valve before BD valve is open and BD valve is closed on
auto. Ensure that it is not passing.
• All controls of HP bypass are on manual mode and all valves are closed.
• Ensure power supply to HP BP panel is normal
• Ensure that control oil pressure to LP bypass station is > 5.5 kg/cm2
• All manually operated & auto injection water valves (V1, V2, V3, V4) of LP
bypass station are closed.
• All the drain valves of HP &LP bypass are open
• Ensure condenser vacuum is > 0.75 kg/cm2
• BFP & CEP are running and discharge header pressures are adequate

26. HP-LP Bypass System

27. HP-LP Bypass System Charging
Operation :
✓ Set the fixed pressure set point of LPBP at 3 kg/cm2
✓ Put the LP Bypass controller on “Auto”
✓ Make the automatic control interface "ON"
✓ Ensure drain valves of CRH, HRH and Warm-up valves are
open
✓ Open HPBP warm-up valves locally.
✓ Set the pressure master set point at 35 kg/cm2
✓ Put spray water control valves BPE1 & BPE2 of HPBP on
“Auto”
✓ After warming up for 15 min. open HPBP valves BP-1 and
BP-2 about 5%.
✓ Increase the BP1 & BP2 position manually in a step of 5%
✓ Check that LPBP valves and injection water valves open on
auto to maintain HRH pressure

28. HP-LP Bypass System Charging
Operation contd… :
✓ Close LPBP warm-up valve
✓ When LPBP position goes to 25% increase the oil-firing rate in
boiler by taking into service CD oil elevation pairs 1-3 & 2-4.
✓ When the controller demand of HP BP matches with BP1 and BP2
actual position, put BP1 and BP2 on auto to maintain M.S. pressure
as per the set point.
✓ Automatic control interface of LP bypass will increase the fixed
pressure set point value to 12 kg/cm2 and then it will be off.
✓ Check the following parameters :
✓ HRH pressure which maintains at 10 –12 kg/cm2
✓ CRH temperature after attemperation which should rise
✓ M.S./HRH temperature should rise
The steam parameters suitable to turbine condition are build-up
through this process to get the required steam temperature and
flow at preset pressure before rolling of turbine

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30. Turbine Start-up
Turbine is ready for start-up