Rr420102 Hydro Power Engineering

Set No. 1

Code No: RR420102

IV B.Tech II Semester Supplimentary Examinations, May 2008 HYDROPOWER ENGINEERING (Civil Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) What are the various sources of energy for generation of power? (b) How would you estimate waterpower potential?

[8+8]

2. What do you understand by run-off-river plants? What are the parts and arrangements of such plants? Draw a neat sketch the plant and explain. [16] 3. (a) What do you mean by pumped storage power plant? Explain in detail. (b) At a pumped storage plant, the two reversible pump-turbines that have been used have the following rating during the pumping operation Speed 225 rpm Head 230 m Discharge 86 m3 /s Determine the approximate submergence necessary. [7+9] 4. (a) Explain with sketches, spherical valves and butterfly valves used in the hydro electric installation. (b) A penstock, with an internal diameter of 1.3 m, supplies water at a head equivalent to 17.6 kg/cm2 . There is a possibility of 22 per cent increase in the pressure due to transient conditions. The design stress and the efficiency of the joint may be assumed to be 1020 kg/cm2 and 85 per cent respectively. Calculate the approximate wall thickness of the penstock required. [8+8] 5. (a) Describe with neat sketch about differential surge tanks. (b) A rectangular channel 2 m wide has a flow with a velocity of 2 m/s and a depth of flow of 1.25 m. The rate of flow at the downstream end is suddenly decreased such that the depth of flow is increased to 2 m. Find the absolute velocity of the resulting surge and the corresponding new discharge. [8+8] 6. What are the various steps involved in the design of a Pelton turbine runner. [16] 7. (a) Enumerate the different types of draft tubes and draw them neatly (b) What is canitation. What is Thomas canitation factor and what is its significance for water turbines. [8+8] 8. (a) Give in detail various advantages of underground power house. (b) Compare and contrast surface power station and underground power stations. [8+8] ⋆⋆⋆⋆⋆ 1 of 1

Set No. 2

Code No: RR420102

IV B.Tech II Semester Supplimentary Examinations, May 2008 HYDROPOWER ENGINEERING (Civil Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. A common load is shared by two stations, one being a base load plant with 25 MW installed capacity and other being a standby station with 30 MW capacity. The yearly output of the standby station is 10.5 ×106 kWh and that of the base load plant is 125 ×106 kWh. The peak load taken by the standby station is 15 MW and this station works for 2500 hours during the year. The base load station takes a peak of 22.5 MW. Find out: (a) Annual load factors for both stations. (b) Plant use factors for both stations. (c) Capacity factors for both stations.

[16]

2. Why hour-to-hour or day-to-day fluctuations occur in supply or demand to the turbine? How do you cater for the same? [16] 3. Following is the record of average yearly flow in a river for 15 years. If the available head is 15 m, construct the flow-duration curve and power-duration curve for the river. S.No. Year Flow (cumecs)

1 2 3 4 5 6 7 1956 1957 1958 1959 1960 1961 1962 905 865 1050 1105 675 715 850

8 9 10 11 12 13 14 15 1963 1964 1965 1966 1967 1968 1969 1970 775 590 625 810 885 1025 1150 925 [16] 4. Explain in detail various methods for determining economical diameter of penstock. [16] 5. What are the functions of a surge tank? Describe with neat sketches the behavior of various types of surge tanks. [16] 6. (a) What is a turbine and what are the various types of turbine? Discuss. (b) What do you mean by inward and outward flow turbine. Give few examples for each case. [8+8] 7. (a) Explain constant speed characterestic curves of turbines.

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Set No. 2

Code No: RR420102

(b) A water turbine develops 130 kW at 230 rpm under a head of 16 m. Determine the scale ratio and the speed of a similar machine which will generate 660 kW when working under a head of 25m. [8+8] 8. Explain in detail about the unit bay, loading bay and control bay of the super structure. [16] ⋆⋆⋆⋆⋆

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Set No. 3

Code No: RR420102

IV B.Tech II Semester Supplimentary Examinations, May 2008 HYDROPOWER ENGINEERING (Civil Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. How are the load factor, capacity factor and utilization factor interrelated? What is the significance of diversity factor? [16] 2. (a) What are the various important parts of a valley dam plant? Explain. (b) What do you mean by pier head power station arrangement of run off river plant. [16] 3. It is contemplated to develop a run-off-river plant on a river. The variation of discharge with head was recorded as follows. Plot the power duration curve. Discharge (cumec) 100 180 215 260 325 370 460 600 700 Head (m) 13.0 12.0 11.75 11.5 11.25 11.0 10.0 9.5 9.25 [16] 4. What are penstocks and of which material can they be manufactured? Under what circumstances each material can be used? [16] 5. What is meant by the celerity of wave in power canals? Derieve an expression for the same. [16] 6. Design a Pelton wheel for a head of 80 m and speed 300 rpm. The Pelton wheel develops 103 kW shaft power. Take Cv = 0.98, speed ratio = 0.45 and overall efficiency = 0.8. [16] 7. (a) Explain how the best performance curve can be obtained with the help of characteristic curves of a reaction turbine. If the turbie has to work at a given head and develop given power at maximum efficiency, how this curve can be used to determine the running speed, gate opening discharge and efficiency. (b) A 14 scale turbine model is tested under a head of 12m. The prototype turbine is required to work under a head of 30 m at a speed of 425 rpm. At what speed the model be run and if it develops 100 Kw and uses 1.14 m3 /sec of water at this speed, what power will be obtained from the prototype turbine, assuming that its efficiency is 3% better than that of the model. Also indicate the type of runner used in this turbine. [8+8] 8. (a) What are the various ways of locating of underground power stations? (b) What are the limitations of underground power house. ⋆⋆⋆⋆⋆ 1 of 1

[8+8]

Set No. 4

Code No: RR420102

IV B.Tech II Semester Supplimentary Examinations, May 2008 HYDROPOWER ENGINEERING (Civil Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. A common load is shared by two stations, one being a base load plant with 25 MW installed capacity and other being a standby station with 30 MW capacity. The yearly output of the standby station is 10.5 ×106 kWh and that of the base load plant is 125 ×106 kWh. The peak load taken by the standby station is 15 MW and this station works for 2500 hours during the year. The base load station takes a peak of 22.5 MW. Find out: (a) Annual load factors for both stations. (b) Plant use factors for both stations. (c) Capacity factors for both stations.

[16]

2. Make a neat sketch of a hydropower plant and show clearly the various elements. Also explain the purpose for which they are provided. [16] 3. (a) Describe the basic features of the pumped storage power plant. (b) A closed cycle pumped storage power plant with a gross head of 350 m, has a head race tunnel 4 m dia and 700 m long. The Powerhouse discharges directly in the lower reservoir. The flow velocity is 6.5 m/s and the friction factor f = 0.018. If the overall efficiencies of pumping and generation are 85 % and 88 % respectively, estimate the plant efficiency. [8+8] 4. What do you mean by anchor block? Explain in detail various ways of design of the anchor blocks. [16] 5. (a) Derive the expression for the water hammere pressure in case of rigid pipe. (b) A power canal, bed width 15 m, may be assumed to be rectangular in shape with a steady state depth of flow of 3 m. The canal supplies water to a power house with three turbines, each turbine rated at a discharge of 30 m3 /s. If the load in the power house is suddenly thrown off so that two of the turbines have to be shut down, what would be the height of the surge in the canal? [8+8] 6. (a) What is a turbine and what are the various types of turbine? Discuss. (b) What do you mean by inward and outward flow turbine. Give few examples for each case. [8+8] 7. (a) Explain constant efficiency curves of turbines.

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Set No. 4

Code No: RR420102

(b) A model turbine has a runner of diameter 0.61m. It develops 50 Kw under a head of 30m at a speed of 4000 rpm. Compute NS and Nu for this model. It is required to build a similar turbine to develop 155 Kw a head of 36m. Calculate the required diameter. [8+8] 8. Explain in detail about the unit bay, loading bay and control bay of the super structure. [16] ⋆⋆⋆⋆⋆

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