Large capacity supercritical steam turbines can improve overall efficiency through increasing steam parameters like pressure and temperature. The document discusses 660MW supercritical steam turbines, which have higher steam inlet pressures up to 300 bar and temperatures above 374°C. This allows significant efficiency gains over subcritical units and lowers emissions. Details are provided on the construction and configuration of the high, intermediate, and low pressure turbine modules, materials used, governing systems, lubrication systems, and other components of 660MW supercritical steam turbines.

1. Large capacity supercritical sets

2. • Over all Efficiency can be improved by:
 Improving internal efficiency
 Adoption of advance steam parameters
Improving thermal efficiency

3. Improvement in efficiency with Increasing inlet
parameters for Steam turbines

4. Parameters for Critical State
• Steam Pressure > 221.2 Bar
• Steam Temperature > 374.15 Deg C
Ultra Supercritical Pressure  300 BAR
Increase in steam parameters results in significant improvement in efficiency
With higher cycle efficiency, the supercritical cycle offers lower emission &
lesser pollutants – SOX , NOX & CO2
0
5
10
15
20
25
30
35
40
45
500 MW 660 MW
Sub critical
170 ata / 537 °C / 537 °C
Super Critical
247 ata / 565 °C / 593 °C
Improvement
4.3 %
Entropy
Temperature
Supercritical Cycles

5. Details of Super-Critical Units in 10th , 11th , 12th &13th 5 Year Plans
Sub Critical
(MW)
660
MW
(No.)
800
MW
(No.)
Super Critical
(MW)
TOTAL
MW
10th Plan 9620 0 0 0 9620
11th Plan 45470 7 1 5420 50890
12th Plan 18270 25 33 42,900 61,170
13th Plan 4000 36 36 52,560 56,560
Power Projections
Comparison between SubCritical & SuperCritical (MW)
9620
45470
18270
4000
0
5420
42,900
52,560
0
10000
20000
30000
40000
50000
60000
10th Plan 11th Plan 12th Plan 13th Plan
Total Subcritical (MW) Total Super critical (MW)

6. Introduction of large capacity super critical
Steam Turbines with power output 660MW

7. HPT IPT LPT
Cross sectional arrangement of
500 mw Steam turbine

8. Cross sectional arrangement of
660 mw Steam turbine

9. Cross sectional arrangement of
800 mw Steam turbine

10. Module 500MW 660MW 800MW
HP Turbine H30-100 H30-100 (H70-V4) H30-100 (H70-V4)
IP Turbine M30-63 M30-63 (I50-V2) M30-100 (I60-V2)
LP Turbine N30-2x10 N30-2x12.5 (L2x12.5) N30-4x8 (L4x8)
HP Valves 2xFV320 2xFV250 2xFV250
IP Valves 2xAV560 2xAV560 2xAV560
Steam Turbine module configuration

11. PARAMETERS UNIT
SUBCRITICAL SUPERCRITICAL
500 MW 660 MW 800 MW
MS PRESSURE ATA 170 247 247
MS TEMPERATURE oC 537 565 565
MAIN STEAM FLOW T/HR 1500 2000 2425
REHEAT PRESSURE ATA 40.5 54 54
RH TEMPERATURE oC 537 593 593
REHEAT FLOW T/HR 1335 1740 2090
FINAL FEED WATER TEMP. oC 253 271 290
CONDENSATE FLOW T/HR 1180 1515 1860
Comparison of parameters

12. Overview of a Large capacity set with
super critical parameters

13. Constructional details of
HP turbine

14. Inner Casing
Inlet
Outer Casing-Barrel type
Exhaust
Shaft Seal-Front
Shaft Seal-Rear
• Single flow
• Double shell casing
– Inner casing axially split
– Outer casing barrel type &
axially divided
– Single exhaust in L/H
• Mono block rotor
• First stage diagonal blading
• Provision for extraction
• Over load valve
• Casing mounted valves
• Transported as single unit
• Single flow
• Double shell casing
– Inner casing : axially split
– Outer casing: Barrel type
– Single exhaust in L/H
• Mono block rotor
• Reaction blading with Integral
shroud
• Casing mounted valves
• Transported as single unit
HP Turbine
500 MW
660 MW

15. HP Turbine

16. HP Turbine

17. HP Turbine
For Over load valve
Extraction Chamber

18. Overload valve

19. HP Turbine

20. Section through HP admission with
sealing between HP inner and outer
shell
Section through HP admission
without sealing between HP inner
and outer shell
500 MW 660 MW
HP Turbine

21. HP Turbine Additional Features

22. Outer Casing (rear)
G17CrMo5-10
HW 19582
G-X12CrMoVNbN9-1
X22CrMoV12-1
HW 10687
Rotor
Inner Casing
HP Moving & Guide
Blades (rear) X12CrMoWVNbN10-1-1
HW19488
G-X12CrMoVNbN9-1
Outer Casing (front)
X12CrMoWVNbN10-1-1
HP Moving & Guide
Blades (front)
Materials of HP turbine

23. HP Turbine with Breech-Nut connection
Breech Nut

24. Constructional details of
IP turbine

25. • Double flow
• Double casing design with horizontal
split
• Inlet from Lower half
• Single Exhaust from upper half
• Extraction connections from lower
half
• Admission blade ring with cooling
Inner Casing
Inlet
Exhaust
Outer Casing
Extraction
Inlet
Rotor
• Double flow
• Double shell casing with horizontal
split
• Mono block rotor
• Reaction blading
• Inlet from Upper & Lower halves
• Two exhaust in L/H
• Extraction connections from Upper
& lower half
IP Turbine
Inlet
Exhaust
500 MW
660 MW

26. IP Turbine –Inlet Ring

27. •Reduction in wall temperature of
the Rotor
•Reduction in Creep damage
•Reduction of Cracking
•Increase of Life cycle time
IP Turbine –Inlet Ring

28. Outer Casing
GGG 40.3
HW 19793
G-X12CrMoVNbN9-1
Rotor
Inner Casing
X12CrMoWVNbN1011
HW19488
HW19688
Guide Blades:
X19CrMoVNbN111
IP Moving (initial stg.) :
NiCr20TiAl
Materials of IP turbine
Guide Blades:
X19CrMoVNbN111
IP Moving (rear stg.) :
NiCr20TiAl

29. IP Turbine with Casing mounted valves

30. Constructional details of
LP turbine

31. • Double flow
• Three shell casing
• Horizontally split
• Mono block rotor
• Reaction blading
• Rigid coupling
• Double flow
• Double shell casing
• Single admission from top half
• Outer Casing & condenser rigidly
connected
• Push rod arrangement to minimize
axial clearances
• Mono block rotor
• Inner / Outer casing fabricated
LP Turbine

32. LPT
LP Turbine - 500MW LP Turbine - 660 MW
LP Turbine

33. EXHAUST
DIFFUSER
ROTOR
LP INNER
INNER CASING
LP INNER OUTER
CASING
GUIDE BLADE
CARRIERS
LP LONGITUDINAL
GIRDER
LP FRONT WALL
ATMOSPHERIC RELIEF
DIAPHRAGM
LP Turbine - 500MW

34. LP Turbine – 660MW
EXHAUST
DIFFUSER
ROTOR
LP INNER OUTER
CASING
LP SIDE WALL
LP END WALL
ATMOSPHERIC RELIEF
DIAPHRAGM
CASING UPPER
PART

35. LP Turbine – 660MW

36. Arrangement of thrust bolt for minimizing
axial clearances

37. 26NiCrMoV14-5
HW 19373
X20Cr13
HW 10786
Rotor
Inner Casing
LP Moving & Guide
Blades Drum Stages
X10CrNiMoV 12-2-2
HW 19392
Last Stage
Moving Blade
X2CrNi12
HW 18802
Hollow Guide
Blades
Fabricated
ST 37-II
AA10401/10119
Outer Casing
Materials for LP turbine
Fabricated
ST 37-II
AA10401/10119

38. Arrangement of thrust bolt for minimizing axial
clearances

39. Banana type guide blade
Last stages of LPT
Improved cylindrical profile blade (TX)
HPT / IPT middle & LPT initial stages
Twisted profile blade (F)
HPT / IPT rear stages
3 Dimensional blade (3 DS)
HPT / IPT initial stages
Turbine Blading

40. Fabricated bearing pedestals Cast bearing pedestals
GGG-40.3 Nodular Casting
Bearing Pedestals

41. Governing System
660 MW steam
turbine equipped
with high pressure
electro-hydraulic
governing system
Advantage:
• Compact design
• Less control fluid piping
• Less erection and commissioning
time

42. Characteristics 500 MW
(Low Pressure Gov.)
660 MW
(High Pressure Gov.)
Operating Pressure 8/32 Bar 160 Bar
IP valves Suspended Casing mounted
Control signal to
Actuator
Hydraulic Electronic
Size of Actuators Bulky Compact
Control & Protection
Elements
Hydraulic / Electro-
hydraulic
Electronic
Governing System

43. Advantages of high pressure EHA based governing system
• Bulky servomotors replaced with compact
actuators leading to compact layout in TG hall
• Governing & protection racks replaced by
electronic systems
• Faster response due to state of art electronic
control and protection systems
• Reduced manufacturing time at shop
• Turbine driven MOP replaced with motor driven
pump
• Mechanical Emergency governor replaced by
electronic protection system, eliminating actual
over speeding at site

44. Additional features
• Less noise because of latest features hence no
cleading up to 85 db
• Hydraulic turning wheel for barring replaced by
Hydraulic turning motor at front bearing pedestal
similar to 250 MW
• Steam strainer elements built in the valves resulting
in elimination of strainer housings

45. LP Bypass valve
Advantages:
1. Considerable reduction in overall space
2. Use of just one actuator, lower control fluid
consumption and simplified C&I. Small
sized HPSU
3. Overall weight of valve assembly will be
less
4. Less number of O&M Spares needed
5. Procurement and O&M cost will be much
less
In 500 MW LP Bypass, combined
stop & control valve is used
For 660 MW, single stem LP
Bypass valve having both stop
& control function will be used

46. Lub oil system in 500 MW set consists of
• Main Oil Tank
• Main Oil Pump (Turbine Driven)
• Auxiliary Oil Pump (2X100%)
• Emergency Oil Pump
• Jacking Oil Pump (2X100%)
• Oil Vapour Exhausters (2X100%)
• Oil Coolers (2X100%)
• Duplex Oil Filters (Lub Oil & Jacking Oil)
• Seal Oil Storage Tank
• Temp control valve, butterfly, pressure limit
valves

47. LUB OIL MODULE
el. temperature
control valve,
Toil=50°C
2x100%
lube oil pumps,
centrifugal pumps, 6 bar
Emergency oil pump,
220V battery voltage
2x100%
lifting oil pumps,
vane pumps,
max. 175bar,
switch off at 9s-1
oil vapor
demister,
acc. to german
regulations
(TA-Luft)
main throttle,
min. flow
lube oil
double filter
(2x100%, 25µm)
return line
2x100%
plate heat exchanger,
controlled by oil side
2x100%
lifting oil filter 25µm,
pressure control valve
tank
module design exemplary
Off-line-filter
OLF60, 3µm
Lub Oil Module in 660 MW

48. OIL MODULE
example
Lub Oil Module in 660 MW

49. • Turbine driven main oil pump in 500
MW set is replaced by motor driven
lub oil pump in 660 MW
Advantage:
1. Injectors in system are avoided
2. Interconnecting pipe between injectors &
MOP is no more required
3. Smaller main oil tank
Main Oil Pump

50. • Electric actuators of angle drain
valves replaced by pneumatic
actuators
Advantage:
In case of loss of control air, valves
move immediately in the defined fail
safe position.
A motorised valve remains in the actual
position in case of power loss and need
to be operated manually
Drain Valves

51. Steam Strainers
Steam strainers in 660
MW unit are located
inside turbine valves
(ESV & IV) and hence
separate strainer
housings in MS & HRH
lines are eliminated.

52. Thanks ……

53. STEAM TURBINE Unit 1 Unit 2
1 H. P. Turbine SAG SAG
2 I. P. Turbine SAG BHEL
3 L. P. Rotor SAG BHEL
4 L. P. Inner casing SAG BHEL
5 L. P. Outer casing BHEL BHEL
6 Cross Around Piping SAG BHEL
7 FB Pedestal SAG BHEL
8 HP Pedestal SAG BHEL
9 IP Pedestal SAG BHEL
10 LP Pedestal SAG BHEL
11 ESV & CV SAG BHEL
12 IVCV SAG BHEL
13 LPBP Valve BHEL BHEL
14 Governing Control Rack NA NA
15 LPBP Control Rack NA NA
16 Valves (CRH NRV, EXTRACTION NRVS,
OVERLOAD VALVES)
SAG BHEL
17 Instruments & Rack SAG SAG
18 Tools & Tackles SAG NA
19 TG Dec Embedments BHEL BHEL
20 Oil Module BHEL BHEL
21 Piping and Mounting Accessories (Turbine
Integral Piping System)
BHEL BHEL
25 Base Plate Assembly BHEL BHEL
800 MW TG SETS
660 MW BARH TG SETS
Division of Work

54. 660 MW TG SETS
AVAILABILITY OF DOCUMENTS:
-The schedule given by Siemens indicates documents flow starting
Oct’ 2009 up to end of 2010.
-This does not suit BHEL
e.g. – LP outer casing is to be supplied by BHEL by February 2011
while Siemens’ date of supply of document is Oct’ 2010. Similar case
exists for other assemblies for set no.-2 (in BHEL scope).
- Preponment of 6-12 months required.
- Detailed letter being sent to Siemens by 10th July 2009.
- Documents for HP module shall be available from Siemens after
signing of TCAE3.

55. 660 MW TG SETS
MANUFACTURING FACILITIES FOR TURBINES:
• Facility planned for weld overlay for HP / IP rotors.
• No other special facility is required for manufacture of these
turbines.
• Machining facilities had been evaluated on the basis of 660 MW
documentation received for Swarzpumpe project.
• Documentation for Barh project is yet to be received. It is envisaged
that being a modular design, major changes necessitating new
machines are not expected.