ELEMENTS

1. ELEMENTS OF Hydraulic POWER PLANTS
D. KANAKARAJA
ASST. PROFESSOR
AITS
TIRUPATI

2. Hydraulic Machines

3. Initially the water of the river is in Catchments Area.
From catchments area the water flows to the dam.
At the dam the water gets accumulated . Thus the potential
energy of the water increases due to the height of the dam .
When the gates of the dam are opened then the water moves
with high Kinetic Energy into the penstock.
Through the penstock water goes to the turbine house.
Since the penstock makes water to flow from high altitude
to low altitude, Thus the Kinetic Energy of the water is again
raised.

4. In the turbine house the pressure of the water is controlled by the
controlling valves as per the requirements.
The controlled pressurized water is fed to the turbine.
Due to the pressure of the water the light weight turbine rotates.
Due to the high speed rotation of the turbine the shaft connected
between the turbine and the generator rotates .
Due to the rotation of generator the ac current is produced.
This current is supplied to the powerhouse .
From powerhouse it is supplied for the commercial purposes.

5. No fuel charges.
Less supervising staff is required.
Maintenance & operation charges are very low.
Running cost of the plant is low.
The plant efficiency does not changes with age.
It takes few minutes to run & synchronize the plant.
No fuel transportation is required.
No ash & flue gas problem & does not pollute the atmosphere.
These plants are used for flood control & irrigation purpose.
Long life in comparison with the Thermal & Nuclear Power Plant.

6. The initial cost of the power plant is very high.
Takes long time for construction of the dam.
Generally, Such plant’s are located in hilly area’s far away from
load center & thus they require long transmission lines & losses in
them will be more.
Power generation by hydro power plant is only dependant on
natural phenomenon of rain .Therefore at the time of drought or
summer session the Hydro Power Plant will not work.

7. PURPOSES OF MULTIPURPOSE
HYDROPROJECT
For irrigation of agricultural land.
For navigation.
For fisheries and tourism.
For flood control.
For civil water supply.
For generation of electricity.

8. Components of hydel scheme
The principal components are:
1. Forebay
2. Intake structure
3. Penstocks
4. Surge tank
5. Turbines
6. Power house
7. Draft tube
8. Tail race

9. PRIMARY ELEMENT’S
CATCHMENTS AREA
RESERVOIR
DAM
PRIME MOVERS
DRAFT TUBES
POWER HOUSE &
EQUIPMENT
SAFETY DEVICE’S
SPILL WAY’S
SURGE TANK
TRASH RACK
intake house.
water way.
Tail race or outlet water way.

10. BASIC ELEMENTS OF HYDEL POWER PLANT
• Reservoir
• Dam
• Trace rack
• For bay
• Surge tank
• Penstock
• Spillway
• Turbine
• Powerhouse

14. The whole area behind the clam training into a stream as river
across which the dam has been built at suitable place is called
catchments area

15. A reservoir is employed to store water which is further utilized to
generate power by running the hydroelectric turbines.
In a reservoir the water collected from the catchment area is stored
behind a dam.
Catchment area gets its water from rain and streams.
The level of water surface in the reservoir is called Head water level.
Note : Continuous availability of water is a basic necessity for a
hydro-electric power plant.

16. A dam is a barrier which confines or raise water for storage or diversion to create a hydraulic
head.
Dam’s are generally made of concrete, Stone masory, Rockfill or Timber
The purpose of the dam is to store the water and
to regulate the out going flow of water.
The dam helps to store all the incoming water. It
also helps to increase the head of the water. In
order to generate a required quantity of power it is
necessary that a sufficient head is available.

17. • Dam are classified based on following factors:
a) Function
b) Shape
c) Construction material
d) Design
a) Based on function the dam may be called as storage dam,
diversion dam or detention dam.
b) Based on the shape the dam may of trapezoidal section &
arch type.
c) The materials used for constructing dams are earth, rock
pieces, stone masonry.
d) According to structural design the dam maybe classified as:
i. Gravity dam
ii. Arch dam
iii. Buttress dam

18. Types of Dam:
1. Masonry Dams.
2. Earth Dams.
The masonry dams are of three major classes:
a) Gravity dam.
b) Buttress dam.
c) Arched dam.
d) Gravity dam:
Resist the pressure of water by its weight.
Construction of material used for his dam, is solid masonry or
concrete.

19. Types of Dam:
1. Masonry Dams.
2. Earth Dams.
The masonry dams are of three major classes:
a) Gravity dam.
b) Buttress dam.
c) Arched dam.
d) Gravity dam:
Resist the pressure of water by its weight.
Construction of material used for his dam, is solid masonry or
concrete.

20. b) Arch dam:
It resist the pressure of water partly due to its
weight and partly due to arch action.
c) Buttress dam:
• Buttress supporting a flat slab.
• When cost of reinforced concrete is high such
type of dam is selected.

21. Arch Dams
• Arch shape gives strength
• Less material (cheaper)
• Narrow sites
• Need strong abutments

22. Arch Dam
Monticello Dam impounds Putah Creek west of Sacramento,
California. The solid concrete structure stands 93 m (304 ft) tall.
The dam’s arched upstream face transfers some of the pressure
from its reservoir, Lake Berryessa, onto the walls of the canyon.

23. Multiple Arch Dam
Bartlett Dam impounds the Verde River northeast of Phoenix, Arizona. Like
all multiple arch dams, Bartlett Dam makes use of a series of arches
supported by buttresses to withstand the pressure of the water in its
reservoir, Bartlett Lake. Each of the dam’s 10 concrete arches has a 7-m (24-
ft) radius and measures 2 m (7 ft) at the base and just 0.6 m (2 ft) at the
crest. The thick base provides additional strength at the bottom of the
reservoir, where the water pressure is most intense.

24. Concrete Gravity Dams
• Weight holds dam in
place
• Lots of concrete
(expensive)

25. Flat Slab Buttress Dam
Lake Tahoe Dam impounds the Truckee River in northern California. Like all
flat slab buttress dams, it has a flat slab upstream face supported by a
series of buttresses on the downstream side. Lake Tahoe Dam measures
5.5 m (18 ft) tall and 33 m (109 ft) long. It was completed in 1913 to raise
the water level in Lake Tahoe, a natural lake, to provide additional water
for crop irrigation.

26. Buttress Dams
• Face is held up by a
series of supports
• Flat or curved face

27. EARTH/ Embankment Dams
• Earth or rock
• Weight resists flow of
water

28. Intake structure
• Water conveyed from forebay to penstocks
through intake structures.
• Main components are trash rack and gate.
• Trash rack prevent entry of debris.

30. .
1. Water ways are the passages, through which the water is conveyed to the
turbines from the dam. These may include tunnels, canals, flumes,
forebays and penstocks and also surge tanks.
2. A forebay is an enlarged passage for drawing the water from the
reservoir or the river and giving it to the pipe lines or canals.
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31. 5 August 2015 31
Excess accumulation of water endangers the stability of dam
construction. Also in order to avoid the over flow of water out of
the dam especially during rainy seasons spillways are provided.
This prevents the rise of water level in the dam.
Spillways are passages which allows the excess water to flow
to a storage area away from the dam.

32.  A gate is used to regulate or control the flow of water
from the dam.
• Modern dams use (1) vertical lift gates, (2) traitor (radial)
• gates, (3) wheeled gates, (a) roller gates, (b) drum or cylindrical
• gates and (c) butterfly valves etc.
 It is a passage that carries water from the reservoir to the
surge tank.
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1. Crest control
2. Crest gates
3. Sluice gates and valves.

38. Surge tank
• additional storage for near to turbine, usually provided in high
head plants.
• located near the beginning of the penstock.
• As the load on the turbine decreases or during load rejection by
the turbine the surge tank provides space for holding water.

39. Surge Shaft
• Surge shaft is located at the end of tunnel .
• It is a well type structure of suitable height
and diameter to absorb the upcoming and
lowering surges in case of tripping and
starting of the machine in the power house.
• The surge shaft is provided with gates to stop
flow of water to the penstock if repairs are to
be carried out in the penstock or inlet valves.

40. Surge tank:
 A Surge tank is a small reservoir or tank in which the water level rises or
falls due to sudden changes in pressure.
Purpose of surge tank:
 To serve as a supply tank to the turbine when the water in the pipe is
accelerated during increased load conditions and as a storage tank when the
water is decelerating during reduced load conditions.
 To reduce the distance between the free water surface in the dam and the
turbine, thereby reducing the water-hammer effect on penstock and also
protect the upstream tunnel from high pressure rise.
Water-hammer effect :
o The water hammer is defined as the change in pressure rapidly above or below normal
pressure caused by sudden change in the rate of water flow through the pipe, according
to the demand of prime mover i.e. turbine
40

41. • surge tank over comes the abnormal pressure
in the conduit when load on the turbine falls
and acts as a reservoir during increase of load
on the turbine.

42. Penstock
• Penstocks are the water conductor conduit of suitable
size connecting the surge shaft to main inlet valve
• It allows water to the turbine through main inlet valve.
• At the end of the penstock a drainage valve is provided
which drains water from penstock to the draft tube.
• In case of long penstock and high head, butterfly valve
is provided just before the penstock.
• It takes off from the surge shaft in addition to spherical
valve at the end of the penstock acting as the main inlet
valve.

43. Penstock thickness:
• The thickness of penstock depend on water head and hoop
stress allowed in the material.
t =
𝑝.𝑑
2𝑓𝜂
Where,
t= Penstock thickness
d= Dia of penstock
𝑓= Permissible stress
p= Pressure due to water including water hammer.

44. Number of penstock
A hydro Power Plant uses a number of turbine which are to be
supplied water through penstock.
• To use a single penstock for the whole a plant.
• To use on penstock for each turbine separately.
• To provide multiple penstock but each penstock supplying water
to at least two turbine.
Factors for Selecting number of penstocks:
• Economy.
• Operational safety.
• Transportation facilities.

45. Penstock Protection Valve
The Penstock protection valves are provided
after the surge shaft to facilitate maintenance
of the penstocks. The valves are of butterfly
type. The BF valve are operated hydraulically
with provision of pressure accumulators in
case of power failure.

46. Forebay
• Enlarged body of water provided in front of
penstock.
• Provided in case of run off river plants and
storage plants.
• Main function to store water which is rejected
by plant.
• Power house located closed to dam penstock
directly take water from reservoir, reservoir
act as forebay.

47. Water Intake Structure
• It consists of gated structure at the
dam/Barrage to control the flow of water and
provided with gates along with hoisting
arrangement.
• Normally these gates remain open and allows
water to flow to the tunnel /channel as the
case may be until and unless water conductor
system is taken under shut down for repair
and maintenance.

48. Pressure Shaft
• When the water conduits in the Surge shaft
and Main Inlet valve are not exposed to the
atmosphere and buried in the
ground/concrete due to its high pressure,
these are called Pressure shaft.

49. Main Inlet Valve
• Main inlet valve works as the gate
valve/isolating valve in the water conductor
system.
• It is located before turbine and allows water
flow from penstock to turbine.
• MIV acts as closing valve and cuts the flow of
water during an emergency trip.
• They are of following type.
• Butterfly valve (upto 200 m head)
• Spherical valve (more than200m head)

50. BUTTERFLY VALVE

51. BUTTERFLY VALVE

52. SPHERICAL VALVE

53. Turbines
• turbines are used to convert the energy water of
falling water into mechanical energy.
• water turbine is a rotary engine that takes energy
from moving water.
• flowing water is directed on to the blades of a
turbine runner, creating a force on the blades.

54. • Since the runner is spinning, the force acts
through a distance n this way, energy is
transferred from the water flow to the
turbine.
• The principal types of turbines are:
1) Impulse turbine
2) Reaction Turbine

57. Kaplan
Francis

58. Draft tube
• is a pipe or passage of gradually increasing
cross sectional area, which connect to the exit
to tail race.
• it reduces high velocity of water discharged
by the turbine.
• draft tube permits turbines to be installed at a
higher level than the tail race level, which
help the maintaince and repair of turbines.

59. Draft Tube
• Draft tube is located between lower ring of turbine
and tail race . It conveys water after discharge from
runner to tail race tunnel.
• Draft tube (DT) gates are provided for isolating the
Power house and tail pool before taking
maintenance of the turbine.
• The DT gates are provided with hoisting
mechanism.
• The DT gate may be a single piece or a combination
of more than one piece

60. Draft Tube:
Reaction turbines must be completely enclosed because a
pressure difference exists between the working fluid (water) in
the turbine and atmosphere. Therefore, it is necessary to
connect the turbine outlet by means of a pipe known as draft
tube upto tailrace level.
Types of Draft Tubes
(1) Conical Draft Tube.
This is known as tapered draft tube and used in all reaction
turbines where conditions permit. It is preferred for low specific
speed and vertical shaft Francis turbine. The maximum cone
angle of this draft tube is limited to 8° (a = 4°). The hydraulic
efficiency of such type of draft tube is 90%.

61. 2- Elbow Type Draft Tube.
The elbow type draft tube is often preferred in most of the power
plants, where the setting of vertical draft tube does not permit
enough room without excessive cost of excavation.
3- Moody Draft Tube.
This draft tube has an advantage that its conical portion at the
center reduces the whirl action of water moving with high velocity
centre reduces.

62. Spill Way’s is a kind of canal provided besides the dam.
Spill Way’s is used to arrange the excess of accumulation of
water on the dam because excess accumulation of water may
damage the dam structure
1. Over flow spillway
2. Chute or trough spillway
3. Side channel spillway
4. Shaft spillway
5. Siphon spillway'.

65. The amount of electricity that can be generated by a
hydropower plant depends on two factors:
• flow rate - the quantity of water flowing in a given
time; and
• head - the height from which the water falls.
The greater the flow and head, the more electricity
produced.
Flow Rate = the quantity of water flowing
Head = the height from which water falls
Power generation

66. Power House.
The power house is a building in which the turbines, alternators
and the auxiliary plant are housed. Some important items of
equipment provided in the power house are as follows:
i. Turbines
ii. Generators
iii. Governors
iv. Relief valve for penstock setting
v. Gate valve
vi. Transformer
vii. Switch board equipment and instruments
viii. Oil circuit breaker
ix. Storage batteries
x. Outgoing connections
xi. Cranes
xii. Shops & offices

67. The surface power house has been broadly divided into three
subdivisions which is separated
from the intake as mentioned below :
(a) Substructure ;
(b) Intermediate structure ;
(c) Super-structure.

68. Tail water level or Tail race:
o Tail water level is the water level after the discharge from the
turbine. The discharged water is sent to the river, thus the level of
the river is the tail water level.
Electric generator, Step-up transformer and Pylon :
 As the water rushes through the turbine, it spins the turbine shaft,
which is coupled to the electric generator. The generator has a
rotating electromagnet called a rotor and a stationary part called a
stator. The rotor creates a magnetic field that produces an electric
charge in the stator. The charge is transmitted as electricity. The
step-up transformer increases the voltage of the current coming
from the stator. The electricity is distributed through power lines
also called as pylon.

69. GENERATOR
• Hydro generator is coupled to the turbine and converts the mechanical
energy transmitted by the turbine to electrical energy
• Generators can be of:
• Suspended type
• Umbrella type
• Main Generator components include:
• Stator
• Rotor
• Upper Bracket
• Lower Bracket
• Thrust Bearing & Guide Bearings
• Slip Ring & Brush Assembly
• Air Coolers
• Brakes & Jacks
• Stator Heaters

70. GOVERNOR
• Used for controlling the guide vanes by
detecting turbine speed & its guide vane
opening in order to keep turbine speed stable or
to regulate its output.
• The performance of the governor dominates the
controllability of the power plant and quality of
electrical power produced .

71. AUXILIARIES ATTACHED WITH HYDEL
POWER PLANT.
(A)Electrical instruments
• Generator
• Exciter,transformers
• Switch gears
• Other instruments of
control room
(B)Mechanical instruments
• Shaft coupling,journal
bearings,thrust bearings
• Lubricating oil system
• Cooling system
• Brake system for
generator-turbine shaft

73. Because water delivery is the first priority, electricity produced at Arizona Falls is used
mainly to supplement high electricity demands in the summer.

74. Hydropower is an important renewable
energy source world wide...

75. we can experience new,
renewable technologies with
the power of water!
Even here
in our desert home,

76. Advantages of hydropower
It is a clean and safe source of energy
They are self sustaining
They create habitat for more types of fish
They can act as a flood controller
They are the most efficient energy source
running from 90-95% efficiency
Other forms of Hydropower
Tidal power: electricity generated by turbines
moved by the tides. This is still in experimental
stages.
Ocean thermal power: power generated by the
thermal expansion of the ocean. This can only
be used in a location like the Gulf stream.
Geothermal power: natural steam is used
underground to turn turbines. This is limited to
location which have these phenomenon.
Advantages of hydropower
It is a clean and safe source of energy
They are self sustaining
They create habitat for more types of fish
They can act as a flood controller
They are the most efficient energy source
running from 90-95% efficiency

77. 1 Itaipu Brazil/
Paraguay
12,600 1984
2 Guri Venezuela 10,300 1968
3 Grand Coulee United
States
6,480 1942
4 Sayano-
Shushensk
Russia 6,400 1980
5 Krasnoyarsk Russia 6,000 1968
6 La Grande 2 Canada 5,328 1982
7 Churchill Falls Canada 5,225 1971
8 Bratsk Russia 4,500 1964
9 Ust-Ilim Russia 4,500 1974
10 Tucurui Brazil 4,245 1984
Rank Name of Dam Location
Rated
Capacity
(Megawatts)
Year of
Completed
World’s Largest Dams
By Power Generating Capacity

78. 1 Owen Falls Uganda 204,800 1954
2 Kariba Zimbabwe
/Zambia
180,600 1959
3 Bratsk Russia 169,270 1964
4 Aswan High Egypt 168,900 1970
5 Akosombo Ghana 148,000 1965
6 Daniel Johnson Canada 141,852 1968
7 Guri
(RaulLeoni)
Venezuela 136,000 1986
8 Krasnoyarsk Russia 73,300 1967
9 W.A.C. Bennett Canada 70,309 1967
10 Zeya Russia 68,400 1978
Rank Name of Dam Country
Storage
Capacity
Cubic
Meters
Year of
Completed
World’s Largest Dams
By Storage Capacity

79. 1 Rogun Tajikistan 335 1989
2 Nurek Tajikistan 300 1980
3 Grand Dixence Switzerland 285 1961
4 Inguri Georgia 272 1980
5 Boruca Costa Rica 267 1990
6 Vaiont Italy 262 1961
7 Chicoasen Mexico 261 1980
8 Manuel M.
Torres
Mexico 261 1981
9 Alvaro
Obregon
Mexico 260 1946
10 Mauvoisin Switzerland 250 1957
Rank Name of Dam Country
Height
(m)
Year of
Completed
World’s Largest Dams
By Height