1. STEAM TURBINE
LOSSES
SHIVAJI CHOUDHURY

2. Challenges
 Rising fuel costs which in most of
power generating companies are
passed through to customer ,caught
the attention to regulating agencies.
 Regulating agencies are now paying
more attention to efficiency of power
plants.

3. Heat Rate Definitions
 Heat rate is defined in units of
kJ/kWh and is simply the amount of
heat input into a system divided by
the amount of power generated by a
system.
 Less heat rate (less fuel) means more
efficient system.

4. BENEFIT -identification of losses
 Efficiency increase
 Green house gases emission decrease
 Particulate emission reduction
 Availability improvement
 Reduction in O&M cost
 Less capacity addition
 Increase profitability

5. Steam Turbine losses
 Symptoms
 HP/IP/LP section efficiency less than
design.
 Causes (any one or more than one)
 Change in internal conditions of turbine
 1.Mechanical damages
 2.Flow area decreases
 3.Flow area bypass
 4.Flow area increases
 Change in inlet conditions

6. 1.MECHANICAL DAMAGES
 Symptoms
 Sudden change in section efficiency.
 Sudden change in section pressure ratio.
 Cause
 Metallurgical defects.
 Maintenance practice.

7. Mechanical damages

8. 2.FLOW AREA DECREASE
 Symptoms
 Increase in pressure ratio
 Decrease in section efficiency
 Increase in up stream pressure
 cause
 Mechanical blockage
 Sudden increase in pressure ratio
 Sudden decrease in section efficiency
 Sudden increase in up stream pressure
 Blade deposits
 Gradual increase in pressure ratio
 Gradual decrease in section efficiency
 Gradual increase in upstream pressure

9. Mechanical blockage

10. BLADE DEPOSIT

11. DEPOSIT IN SINGLE STAGE
CASING TURBINE

12. SOLUBILITY TRENDS THROUGH
TURBINE

14. 3.FLOW AREA BYPASS
 Symptoms
 Decrease in section efficiency
 Decrease in pressure ratio
 Decrease in upstream pressure
 Cause
 Hp turbine bushing leakage
 Main steam stop valve leakage
 HP gland seal leakage
 IP stop/intercept valve leakage
 IP turbine bushing leakage

15. 4.Flow area increase
 Symptoms
 Decrease in pressure ratio
 Decrease in section efficiency
 Decrease in upstream pressure
 Cause
 Spill strip or packing leakage
 Erosion of turbine stages
 Solid particle erosion of nozzle block
 Blade mechanical damage

16. Spill strip or packing leakage
 Symptoms
 Increased down stream extraction temperatures
 Sudden decrease in stage efficiency
 Cause
 Thermal stress
 Rubbing
 Vibration
 Operating procedures

17. Solid particle erosion of nozzle
blocks
 Symptoms
 Increase in pressure down stream of first
stage
 Increase in ratio of first stage to throttle pressure
 Cause
 Cycling
 Exfoliation in boiler tubes
1. Condenser tube leak
2. Poor water chemistry

18. Erosion of turbine stages
 Symptoms
 Gradual decrease in pressure ratio
 Gradual decrease in section efficiency
 Gradual decrease in upstream
pressure

19. Blade mechanical damages
 Symptoms
 Sudden decrease in pressure ratio
 Sudden decrease in section efficiency
 Sudden decrease in upstream
pressure.

20. Cross section of turbine –showing
efficiency loss due to leakage
Leaking steam not
contribution to power
generation (in RED)

21. SOLID PARTICLE EROSION

22. TURBINE EFFICIENCY AND SURFACE FINISH OF
BLADE SURFACE

23. Impact of parameter deviation from design
parameters on HEAT RATE (210 MW ,KWU
Turbine )-operator controllable parameters..
SN PARTICULAR UNIT DESIGN
PARAMETERS
INCREASE in
HEAT RATE DUE
TO DEVIATION
from design
parameter (IN
KCAL/KWH )
MULTIPLICATIO
N
FACTOR
1 PARTIAL LOADING MW 210 24.7 PER 20 MW 1.235
2 MS PRESS KG/CM2 150 25.5 PER 20
KG/CM2
1.275
3 MS TEMP AT HPT INLET DEG C 535 7.5 PER 10 DEG
C
0.75
4 HRH TEMP AT IPT INLET DEG 535 6.6 PER PER
10 DEG C
0.66
5 CONDENSER VACUUM mmHg 660 23.4 PER 10 mm
Hg
2.34
6 FEED WATER TEMP DEG C 241 16 PER 20 DEG
C
0.8
7 RH ATTEMP FLOW T/HR 0 6.4 PER 10 T/HR 0.64
8

24. Turbine
cylinder
efficiency
TURBINE- 500 MW

25. Turbine cycle -500 mw
Controllable
losses
Impact of
Parameter deviation

27. LOSSES IN A THERMAL POWER
PLANT (CEA)

28. HP CYLINDER EFFICIENCY
KWU TURBINE 210 MW
S.N DESCRIPTION UNIT DESIGN OPERATING
1 POWER OUTPUT MW
210
210
2 INLET PRESS TO HP CYLINDER KG/CM2 150 139.7
3
INLET TEMP TO HP CYLINDER DEG C 535 537.8
4
OUTLET PRESS FROM HP
CYLINDER
KG/CM2 38.1 38.9
5
OUTLET TEMP FROM HP
CYLINDER
TEMP 334.8 361.3
6
ENTHALPY OF INLET STEAM KCAL/KG 814.73 819.25
7
ISENTROPIC ENTHALPY AFTER EXPANSION KCAL/KG 719.95 728.77
8
ACTUAL ENTHALPY AFTER EXPANSION KCAL/KG 730.88 746.15
9 CYLINDER EFFICIENCY
% 88.4
7
80.9
INCREASED

29. THANKING YOU