Power Plant Familiarization1. Where the Latent & Superheat is added to Thermal Power Plant?

Ans] The Latent Heat is added in the Combustion chamber when the boiler drum water passes through the riser. Super heated heat is added in the low temperature super heater & the Platen & the final super heater.

2. Auxiliary chart of main condensate & feed water cycle?

Ans] Main condensate cycle:-a] CEP, Main ejector, gland steam cooler 1 , Condensate regulating valve, LP heater number 1, Gland steam cooler 2, LP Heater no.2 to LP Heater no.4, Vent condenser, deaerator.

Feed water Cycle:- Feed storage tank, Booster Pump, Boiler Feed Pump, HP heaters including Suction Discharge and Bypass valves, Feed station, economizer & boiler drum. From Boiler drum to down comer, bottom ring header, risers, upper ring header & boiler drum.

3. Draw coal handling cycle from wagon tippler to coal bunkers?

GENERAL LAYOUT OF CHP

Wagon tippler Crusher

House

Bunkers

Tripper Trolley

Conv. Belts

Vibrating Screens

Crushers

Feeders Surge Hopper

4. Calculation of Open cycle G.T & C.C.G.T Plant?5. Differentiate between Carrnot & Rankine Cycle?6. Why steam is condensed after expansion?7. Describe natural & Forced Convective heat transfer?8. Calculate LMTD Condenser Problem?

9. Draw the flow diagram of flue gas cycle, primary and secondary air cycle of 210MW, Koradi Plant?

10. What is the advantage of Unit Auxiliary Transformer against station transformer?

Ans] Unit Auxiliary transformer is having the auxiliaries of that particular unit, hence the auxiliaries of that unit is taken in service before this step up transformer, otherwise if we use the station transformer, then the power of the auxiliaries required for that particular unit will be first sent to the grid, through the step up transformer & then again taken back from the grid through the station transformer. This will unnecessarily increase the capacity of the step up transformer.

11. Which type of water is used in general service system?

Ans] A soften water is used in the general service systems, so that there will not be any type of deposition in the cooler surface area or bearing cooling area.

12. Draw the cycle of G.S hot water & G.S water system?

13. Four laws of thermodynamics?14. Definition of Boiler?

15. Draw main steam flow cycle of Turbine?

16. WBT, ABT, Range approach of C.T?17. Specific answer of evaporative cooling?

18. Write the purpose of POR & DPR in Generator seal oil system?

Ans] POR means trace oil regulator. Its value is from 1.2KG/per Sq.cm to 1.8Kg/per Sq.cm. POR press the Seal Babbits of the seal bearing. If the POR pressure increases there is a possibility of rise in the seal babbits temperature & if The POR is pressure is less, there is a possibility of leaking of Seal oil in the generator.

DPR means Differential pressure regulator. DPR Maintains seal oil pressure .08Kg/per Sq.cm above the hydrogen pressure, so that the sealing of the hydrogen to be done properly. Hydraulic damper tank, which is a storage device of the seal oil, so that the same oil can be used in case of total AC failure & non availability of DC seal oil pump, as Hydraulic damper tank is approximately six meter above the DPR, & as its pressure is .08 Kg/per sq.cm above the hydrogen pressure. Hence, the seal oil can easily be filled in the damper tank.

19. Write short note on turbine gland seal system?

Ans] Turbine gland seal system is used for sealing the glands of HPT, IPT & LPT. Practically the gland steam pressures of HPT & IPT are in the pressurized form & that of LPT is in vacuum form. Therefore, we have to seal the glands of the turbine, so that there will not be any leak steam from the HPT & IPT glands and there will not be any type of in grace of air, in case of LPT turbine glands.

20. Summary about thermal Power Plant?

21. What is the use of HP/LP Bypass system?

Ans] HP-LP bypass station is mainly used for the conditioning of the main steam & the hot rate temperature & pressure. Its second use is load throw of device in case of tripping of TA set.

22. Write short note of starting interlock of HPLP Bypass system?

Ans] Starting interlock of HP-LP bypass station are as follows:-

A] Vacuum of the condenser must be above 570mm of Mercury.

B] Step up transformer breaker must be in off position.

23. How will you purge the H2 in case of total AC Failure, if D.C system is not available?24. NPSH, Cavitations, 25. Reheating

Generator1. Why hydrogen is used as a cooling medium is generator?

Ans] Hydrogen is used as a cooling medium in Generator because of the following reasons:-

1] It is a very good cooling medium. 2] Density Less. It is a light gas; it can go to any corner of Stator /Rotor. 3] Windage losses are less. 4] It is mono-oxidizing agent, so less corrosion in the internal part of stator & Rotor.

2. Why the stator of a generator is made of Lamination?

Ans] The stator of a generator is made of Lamination in order to reduce iron loss in stator. The hyton loss is reduced due to small thickness of Lamination.

3. The air gap Flux will decide following parameter in Generator?

Ans] The air gap flux decides the following parameter in Generator:-

1] Voltage 2] Stability of Generator 3] connected to System

4. What is the Function of Pilot Exciter, Main exciter?

Ans] To Supply excitation D.C Power to Power To generator rotor Coils.

5. What is the advantage of using excitation transfer furnace over D.C. Exitor?

Ans] Being a transformer it has less possibility of failure, due to no moving parts, it has high, hence less loss, less maintenance.

6. Why generator is less stable when operating on leading power factor?

Ans] generator is less stable when operating on leading power factor because the flux in air gap is controlled by armature reaction which depends upon load & is subject to abrupt variations making the generator unstable.

7. What are the main functions of AVR?

Ans] As per the name of AVR, the main function of automatic voltage regulator is to regulate the generating voltage as per grid system.

8. Why unbalanced load is harmful for generator?

Ans] The unbalance load creates heating of rotor due to negative sequence components in supply system, which may damage retaining rings.

9. What is the advantage of Brushlus excitation system?

Ans] There are minimum contact by eliminating, slip rings, commutator, brushes etc. hence reliability increases.

10. At the time of synchronization the incoming machine should be faster – Why?

Ans] At the time of synchronization the incoming machine should be faster, otherwise there is a chance that the reverse power may operate.

11. Can you synchronize the generator, if its frequency is exactly equal to grid? Give reason?

Ans] No, we cannot synchronize the generator, if its frequency is exactly equal to grid, because the synchroscope will not work.

12. What are the effects of wrong synchronization?

Ans] The effects of wrong synchronization is damage to turbo generator, due to mechanical shocks and power grid disturbances.

Boiler1. Q1] 3000 K cal/Kg coal, find the heat rate, the specific coal consumption is respectively 1] .90

Kg/KWH 2] .80 Kg/KWH 3] 0.75 Kg/KWH 4] .55 Kg/KWH.

Ans] I] Specific coal consumption- 0.90 Kg/ KWH, Plant capacity 30MW,

Heat rate= 3000 * K Cal/Kg *Kg/KWH

= 2700 K Cal / KWH.

II] 0.8 Kg /KWH, Plant Capacity= 60MW

Heat Rate= 3000 * 0.8

=2400 K Cal/KWH.

III] 0.75 Kg/KWH, Plant capacity= 100MW

Heat rate= 8000* 0.75

= 2250 K Cal/KWH

IV] 0.70 Kg/KWH, Plant capacity = 210 MW

Heat Rate= 0.70 * 3000

= 2100 K cal/ KWH

V] 0.60 Kg/KWH, Plant Capacity = 500MW

Heat Rate= 0.60* 3000

= 1800 K Cal /KWH

VI] 0.55 Kg/KWH, Plant Capacity = 660MW

Heat Rate = 3000 *0.55

= 1650 K cal /KWH.

2. Draw the boiler diagram and show the heating surfaces?Ans]

3. Shows drum internals?Ans]

4. Why the economizer is so called?

Ans] As the economizer takes the waste heat from the fuel gas & increases the feed water temperature causing reduction in coal consumption during heating of the feed water for converting heat into steam. By this process we save the fuel & the economy of the plant is increased. Hence, it is called as economizer.

5. Short notes:-

A] Tangent Tube Construction:-

This construction consists of water wall placed side by Side nearly touching each other. An envelope of thin sheet of steel called “SKIN CASING” is placed in contact with the tubes, which provides a seal against Furnace leakage. Refer pg no. 43 for the diagram of your NTPC book.

B] Membrane Wall:-

In this type a number of tubes are joined by a process of fusion welding or by means of steel stripes called fins. This offers many advantages: - 1] Increases in Efficiency 2] Better load response 3] Heat transfer is better 4] Erection is made easy. Refer pg no. 43 of your NTPC Book.

6. Draw schematic balanced draft diagram from F.D Fan to Chimney?

7. Draw a neat figure of Bowl mill and name the important parts?

8. Draw the neat diagram of drag chain feeder?

9. Lube oil system for coal mill?

10. Write conditions for starting of F.D Fans?

11. Draw all logic diagrams done in the class + Logic diagrams for CEP & FWP?

Turbine

1. Write down the function of the following: - a] Axial Guide Key b] Transverse Key c] Vertical Exp.Key d] Difference between 210MW LMW/KMU Turbine.

2. State functions of condenser?3. State material of Condenser Tubes?

Ans] The material of Condenser Tubes is Cupro Nickel & Brass.

4. How do you suspect Tube leakage in condenser?5. Write down difference between Lubricating oil system for 210MW LMW & KWU Turbine?6. Write down why FRF System is used in 500MW KWU Turbine?7. What is the difference between 210MW LMW & 210MW KWU Turbine gland seal system?

Balance of plant

1. What is the most important criteria of major concern of CHP?2. What is gravity take up of Pulley?3. What is the rate of unloading of wagon on rotary wagon tippler?4. What are the protections used in CHP?5. Short note on a] Flocculation b] coagulation c] Filtration6. State impurities in water & there effects?7. Explain application of chlorine in pretreatment of water?8. Draw a neat diagram of DM Plant & explain DM water production with reactions?9. Define corrosion?10. Explain electrochemical corrosion?11. What is electrode potential?12. Short note: a] concentration cell b] Pitting corrosion c] intergranular corrosion?13. Waterline corrosion?14. What are the ways & means combating corrosion?15. State the steps of process of chemical cleaning of steam generation system?16. State importance of Alkali boiling out?17. Why circulating acid solution drain under nitrogen gas capping?18. What for soda ash solution circulated for 8 to 10 hrs?19. Which chemicals are used for post operation chemical cleaning? State reactions?20. Explain wet preservation?21. Explain Osmosis & Reverse osmosis?