Turbine Generator Basics
1. Explain the principle of working of impulse steam turbine.
When steam enters the turbine it suffers a change in direction and momentum, which
gives rise to the rotation of the turbine. There will be no drop in pressure in impulse
steam turbine.
2. Mention the four processes involved in Renkine cycle.
Saturated liquid line.
4 1
Saturated vapour line.
3’
3 2
1 – 2 Expansion process.
2 – 3 Constant pressure heat rejection.
3 – 3’ Reverse adiabatic expansion.
3 – 4 and 4 – 1 Constant pressure heating.
3. What are the methods of removing moisture from turbine?
a. External method by moisture separator and reheater, which separates the moisture
and reheates the steam.
b. Internally by stainless steel mesh, which reduces moisture (water particles) to
1%.
c. By main steam reheat.
4. Define capacity factor.
Capacity factor can be defined as net power produced by the plant divided by perfect
net power that can be produced in the plant.
Capacity factor = Net power produced / Perfect net power produced.
5. What is the purpose of turbine governing system?
Turbine governing system governs the speed of the turbine with the help of
centrifugal governer. It reduces the steam inlet when turbine over speeds.
6. What are the benefits of feed water heating?
a. It improves the plant efficiency.
b. Feed water is heated nearer to saturation point thus thermal shock to boiler is
avoided.
7. Mention parameters monitored by turbovisory instruments.
a. Speed governing.
b. Eccentricity monitoring.
c. Vibration monitoring.
d. Valve position monitoring.
e. Temperature monitoring.
f. Pressure monitoring.
g. Level monitoring.
h. Gas leak monitoring.
i. Conductivity monitoring.
j. Flow monitoring.
8. What are the purposes of turning gear?
Turning gear is used to run the turbine from rest to low speed and from normal
running speed to low speed with the help of barring motor to eliminate the hogging
and sagging of turbine because of the high temperature.
9. Explain the differences between the two types of feed water heaters.
a. Open type: In which bleed steam and condensed water are mixes directly and there
is also dearation of steam.
b. Closed type (shell type): It has tubes and shell. The water passes through the tubes
and steam passes through shell. The heat exchange takes placcce through the
metal tubes.
10. Why condenser back-pressure must be low? How it is achieved?
Condenser back- pressure must be low, because steam should be dumped into the
condenser so as to recycle it to boiler through the recycle process. It improves
efficiency of the turbine, as the heat rejection is less. It is achieved by the help of
ejectors and also passing cold water in the condenser through the tubes of the
condenser so that maximum vacuum can be obtained.
11. What are the materials used for TG rotor and blades?
TG rotor is made up of alloy steel and blades are made up of stainless steel.
12. Define the term heat rate?
Heat rate is defined as the heat supplied in to the plant in Btu by power generated or
output by the plant in kWh.
Heat rate = Heat supplied in Btu / Power output in kWh.
13. What is the purpose of gland steam system?
Gland steam system is provided to arrest the steam leak from the turbine and to
protect the air ingress into the turbine.
14. Explain the main difference between impulse and reaction turbine.
When the inlet pressure of steam to the turbine is equal to outlet pressure of steam
from the turbine the turbine is called the impulse turbine. In this type the heat is
added is very less.
In reaction turbine the outlet pressure of steam is less than the inlet pressure of the
steam. There is reduction in pressure with the increase in kinetic energy.
15. What is meant by hydrodynamic film lubrication?
In high-speed turbines the lubricating oil will be at the sides and there is metal to
metal contact when turbine at rest. When the turbine speeds up there is pressure
pushing the oil through the metal to metal contact. When turbine finally achieves its
speed the oil film breaks the barrier and it takes the load on itself. This is
hydrodynamic lubrication.
16. How does the hydrostatic lubrication differ from hydrodynamic type?
In hydrostatic lubrication which is used in slow speed turbines the lubricating oil is
pressurised externally where as in hydrodynamic system it forms oil film by its speed
which pushes the lubrication oil to form film.
17. What are the functions of dearator?
Dearator removes non-condensable gases (O2), which gets added in the steam and it,
mixes steam with the condensed water for feed water heating. This is a contact type
feed water heater.
18. Why non-return valves are provided in the steam extraction lines?
Non-return valves are provided because when the turbine trips there will be an
instant drop in pressure inside the turbine. But there will be steam in feed water
heaters, which is at high pressure. These will rush in to the turbine and overspeed
will be there in turbine. So non-return valves are provided in steam extraction lines
to prevent over speeding of turbine.
19. What is the function of the steam traps?
During startup the steam traps will bypass turbine drains.
20. What do the term sensible heat and latent heat mean?
Sensible heat: We can measure the rise in temperature. When we add more heat to a
substance. Example – heat that added to water from 0º C to 100º C. This added heat
is measured as sensible heat.
Latent heat: Though there is addition of heat there will be no rise in temperature.
This is latent heat. Example – when water boils at 100º C though we added more
heat the temperature remains at 100º C till all water becomes steam.
21. How are the generator rotor and stator cooled?
Passing highly DM water through the hollow conductor of the generator cools
generator stator and rotor is cooled by hydrogen.
22. What is function of seal oil system?
Seal oil prevents the leakage of hydrogen from the generator casing to the
atmosphere, where it can form explosive mixture. Seal oil is at higher pressure than
hydrogen.
23. What are the base load and peak load power stations?
During certain periods the load demands are very high. Example the morning when
all factories operate. During these time certain power plants like thermal plants gives
this extra power required. These are the Peak load stations, which operates at certain
periods.
But during the rest of period that is when there is no peak power demand there are
some power stations, which cater to the base load always runs giving power to the
grid. These stations are producing power at constant rate. These stations can not be
easily stopped or restated. Nuclear power station comes under Base load power
station category.
24. What are two types of governing system.
Throttle governing system: In this a valve (just like tap water controlling) which
reduces the steam pressure controls the steam flow. This has very less efficiency.
Nozzle governing: In this the steam floe is reduced but the pressure remains the
same. This is achieved by four valves in which when one is closed to 25% of steam
is reduced. This is efficient way of governing.
https://www.youtube.com/channel/UC4_D50vMu1wbQrPaLFYo6Eg https://www.youtube.com/channel/UC4_D50vMu1wbQrPaLFYo6Eg RRB JE, SSC AE/JE UPSSSC JE, SSC JE, CIVIL ENGINEERING MCQs, ELECTICAL ENGINEERING MCQs, preavious year quesion papers, dmrc, lmrc, drdo,rrb ntpc, ntpc, pgcil, dsssb, states board, GATE IES EE, ESE, ECE, ME, CE, IT & CS EXAM MATERIALS & OLD PAPERS Electrical Engineering https://t.me/pravendrarajpoot Daily news & current affairs in hindi & english fully updated Daily current affairs https://t.me/newsdailypkr Engineering Discussion group for your upcoming exams, you can ask your any query regarding your problem,👇👇👇 https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA PKR ELECTRICAL ENGINEERING I am sure this is the best place for you guys subscribe and get success IF YOU WANT TO JOIN ME ON TELEGRAM FOR PDF @newsdailypkr AE/JE EE, ESE, ECE, ME, CE, IT & CS EXAM MATERIALS & OLD PAPERS Electrical Engineering https://t.me/pravendrarajpoot facebook page:- Pravendra Kumar Rajpoot https://t.me/newsdailypkr https://chat.whatsapp.com/5AS7dNFTP4H4vVsiWsqHrT https://t.me/srk50 https://t.me/pravendrarajpoot https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA https://t.me/pravendrarajpoot Daily news & current affairs in hindi & english fully updated Daily current affairs https://t.me/newsdailypkr Engineering Discussion group for your upcoming exams, you can ask your any query regarding your problem,👇👇👇 https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA PKR ELECTRICAL ENGINEERING I am sure this is the best place for you guys subscribe and get success IF YOU WANT TO JOIN ME ON TELEGRAM FOR PDF @newsdailypkr AE/JE EE, ESE, ECE, ME, CE, IT & CS EXAM MATERIALS & OLD PAPERS Electrical Engineering https://t.me/pravendrarajpoot facebook page:- Pravendra Kumar Rajpoot https://t.me/newsdailypkr https://chat.whatsapp.com/5AS7dNFTP4H4vVsiWsqHrT https://t.me/srk50 https://t.me/pravendrarajpoot https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA
1. Explain the principle of working of impulse steam turbine.
When steam enters the turbine it suffers a change in direction and momentum, which
gives rise to the rotation of the turbine. There will be no drop in pressure in impulse
steam turbine.
2. Mention the four processes involved in Renkine cycle.
Saturated liquid line.
4 1
Saturated vapour line.
3’
3 2
1 – 2 Expansion process.
2 – 3 Constant pressure heat rejection.
3 – 3’ Reverse adiabatic expansion.
3 – 4 and 4 – 1 Constant pressure heating.
3. What are the methods of removing moisture from turbine?
a. External method by moisture separator and reheater, which separates the moisture
and reheates the steam.
b. Internally by stainless steel mesh, which reduces moisture (water particles) to
1%.
c. By main steam reheat.
4. Define capacity factor.
Capacity factor can be defined as net power produced by the plant divided by perfect
net power that can be produced in the plant.
Capacity factor = Net power produced / Perfect net power produced.
5. What is the purpose of turbine governing system?
Turbine governing system governs the speed of the turbine with the help of
centrifugal governer. It reduces the steam inlet when turbine over speeds.
6. What are the benefits of feed water heating?
a. It improves the plant efficiency.
b. Feed water is heated nearer to saturation point thus thermal shock to boiler is
avoided.
7. Mention parameters monitored by turbovisory instruments.
a. Speed governing.
b. Eccentricity monitoring.
c. Vibration monitoring.
d. Valve position monitoring.
e. Temperature monitoring.
f. Pressure monitoring.
g. Level monitoring.
h. Gas leak monitoring.
i. Conductivity monitoring.
j. Flow monitoring.
8. What are the purposes of turning gear?
Turning gear is used to run the turbine from rest to low speed and from normal
running speed to low speed with the help of barring motor to eliminate the hogging
and sagging of turbine because of the high temperature.
9. Explain the differences between the two types of feed water heaters.
a. Open type: In which bleed steam and condensed water are mixes directly and there
is also dearation of steam.
b. Closed type (shell type): It has tubes and shell. The water passes through the tubes
and steam passes through shell. The heat exchange takes placcce through the
metal tubes.
10. Why condenser back-pressure must be low? How it is achieved?
Condenser back- pressure must be low, because steam should be dumped into the
condenser so as to recycle it to boiler through the recycle process. It improves
efficiency of the turbine, as the heat rejection is less. It is achieved by the help of
ejectors and also passing cold water in the condenser through the tubes of the
condenser so that maximum vacuum can be obtained.
11. What are the materials used for TG rotor and blades?
TG rotor is made up of alloy steel and blades are made up of stainless steel.
12. Define the term heat rate?
Heat rate is defined as the heat supplied in to the plant in Btu by power generated or
output by the plant in kWh.
Heat rate = Heat supplied in Btu / Power output in kWh.
13. What is the purpose of gland steam system?
Gland steam system is provided to arrest the steam leak from the turbine and to
protect the air ingress into the turbine.
14. Explain the main difference between impulse and reaction turbine.
When the inlet pressure of steam to the turbine is equal to outlet pressure of steam
from the turbine the turbine is called the impulse turbine. In this type the heat is
added is very less.
In reaction turbine the outlet pressure of steam is less than the inlet pressure of the
steam. There is reduction in pressure with the increase in kinetic energy.
15. What is meant by hydrodynamic film lubrication?
In high-speed turbines the lubricating oil will be at the sides and there is metal to
metal contact when turbine at rest. When the turbine speeds up there is pressure
pushing the oil through the metal to metal contact. When turbine finally achieves its
speed the oil film breaks the barrier and it takes the load on itself. This is
hydrodynamic lubrication.
16. How does the hydrostatic lubrication differ from hydrodynamic type?
In hydrostatic lubrication which is used in slow speed turbines the lubricating oil is
pressurised externally where as in hydrodynamic system it forms oil film by its speed
which pushes the lubrication oil to form film.
17. What are the functions of dearator?
Dearator removes non-condensable gases (O2), which gets added in the steam and it,
mixes steam with the condensed water for feed water heating. This is a contact type
feed water heater.
18. Why non-return valves are provided in the steam extraction lines?
Non-return valves are provided because when the turbine trips there will be an
instant drop in pressure inside the turbine. But there will be steam in feed water
heaters, which is at high pressure. These will rush in to the turbine and overspeed
will be there in turbine. So non-return valves are provided in steam extraction lines
to prevent over speeding of turbine.
19. What is the function of the steam traps?
During startup the steam traps will bypass turbine drains.
20. What do the term sensible heat and latent heat mean?
Sensible heat: We can measure the rise in temperature. When we add more heat to a
substance. Example – heat that added to water from 0º C to 100º C. This added heat
is measured as sensible heat.
Latent heat: Though there is addition of heat there will be no rise in temperature.
This is latent heat. Example – when water boils at 100º C though we added more
heat the temperature remains at 100º C till all water becomes steam.
21. How are the generator rotor and stator cooled?
Passing highly DM water through the hollow conductor of the generator cools
generator stator and rotor is cooled by hydrogen.
22. What is function of seal oil system?
Seal oil prevents the leakage of hydrogen from the generator casing to the
atmosphere, where it can form explosive mixture. Seal oil is at higher pressure than
hydrogen.
23. What are the base load and peak load power stations?
During certain periods the load demands are very high. Example the morning when
all factories operate. During these time certain power plants like thermal plants gives
this extra power required. These are the Peak load stations, which operates at certain
periods.
But during the rest of period that is when there is no peak power demand there are
some power stations, which cater to the base load always runs giving power to the
grid. These stations are producing power at constant rate. These stations can not be
easily stopped or restated. Nuclear power station comes under Base load power
station category.
24. What are two types of governing system.
Throttle governing system: In this a valve (just like tap water controlling) which
reduces the steam pressure controls the steam flow. This has very less efficiency.
Nozzle governing: In this the steam floe is reduced but the pressure remains the
same. This is achieved by four valves in which when one is closed to 25% of steam
is reduced. This is efficient way of governing.
https://www.youtube.com/channel/UC4_D50vMu1wbQrPaLFYo6Eg https://www.youtube.com/channel/UC4_D50vMu1wbQrPaLFYo6Eg RRB JE, SSC AE/JE UPSSSC JE, SSC JE, CIVIL ENGINEERING MCQs, ELECTICAL ENGINEERING MCQs, preavious year quesion papers, dmrc, lmrc, drdo,rrb ntpc, ntpc, pgcil, dsssb, states board, GATE IES EE, ESE, ECE, ME, CE, IT & CS EXAM MATERIALS & OLD PAPERS Electrical Engineering https://t.me/pravendrarajpoot Daily news & current affairs in hindi & english fully updated Daily current affairs https://t.me/newsdailypkr Engineering Discussion group for your upcoming exams, you can ask your any query regarding your problem,👇👇👇 https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA PKR ELECTRICAL ENGINEERING I am sure this is the best place for you guys subscribe and get success IF YOU WANT TO JOIN ME ON TELEGRAM FOR PDF @newsdailypkr AE/JE EE, ESE, ECE, ME, CE, IT & CS EXAM MATERIALS & OLD PAPERS Electrical Engineering https://t.me/pravendrarajpoot facebook page:- Pravendra Kumar Rajpoot https://t.me/newsdailypkr https://chat.whatsapp.com/5AS7dNFTP4H4vVsiWsqHrT https://t.me/srk50 https://t.me/pravendrarajpoot https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA https://t.me/pravendrarajpoot Daily news & current affairs in hindi & english fully updated Daily current affairs https://t.me/newsdailypkr Engineering Discussion group for your upcoming exams, you can ask your any query regarding your problem,👇👇👇 https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA PKR ELECTRICAL ENGINEERING I am sure this is the best place for you guys subscribe and get success IF YOU WANT TO JOIN ME ON TELEGRAM FOR PDF @newsdailypkr AE/JE EE, ESE, ECE, ME, CE, IT & CS EXAM MATERIALS & OLD PAPERS Electrical Engineering https://t.me/pravendrarajpoot facebook page:- Pravendra Kumar Rajpoot https://t.me/newsdailypkr https://chat.whatsapp.com/5AS7dNFTP4H4vVsiWsqHrT https://t.me/srk50 https://t.me/pravendrarajpoot https://t.me/joinchat/JObxeA7n6S4qvnegrGhTgA
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