The document discusses hydroelectric power plants. It describes how hydroelectric power utilizes the potential and kinetic energy of water using components like dams, reservoirs, penstocks and turbines. It classifies hydroelectric plants based on available water quantity, head, and load served. Run-of-river and reservoir plants are described. Common turbine types like Francis, Kaplan and Pelton are mentioned for different heads. The document outlines the various components of hydroelectric plants including intake gates, penstocks, draft tubes and switchyards. Advantages like no emissions and lower operating costs are contrasted with disadvantages of location dependence and environmental impacts.

1. HYDRO ELECTRIC POWER PLANT

2. INTRODUCTION
 The energy of water utilized for hydro-power generation may
be kinetic or potential
 Kinetic energy of water is its energy in motion and is a
function of mass and velocity
 Potential energy is a function of the difference in water in
between two points
 Life of hydro power plant is higher than thermal and nuclear
power plants
 However capital cost for the construction and commissioning is
more than TPS and NPS
 It requires less man-power
 Less pollution
 Unit cost of production of energy is low, because main fuel is
water

3. HYDROLOGY
Precipitation: Water falls from atmosphere to the earth surface by
two ways
(i) Liquid precipitation (Rain fall)
(ii) Solid precipitation (snow, Hail)
 Some part of precipitation is lost due to evaporation, interception
and transpiration
Transpiration: Plants absorbing moisture and giving it off to the
atmosphere
• Stream flow = precipitation – losses
• Surface flow is also known as run-off.
Run-off: It is that portion of precipitation which makes its way
towards streams, lakes or oceans

4. HYDROLOGY
 First requirement – Q (discharge)
 Hydrology deals with occurrence and
distribution of water over and under earth’s
surface.
Surface Water Hydrology
Ground Water Hydrology
Watershed, catchment area or drainage area: length of
the river, size and shape of the area it affects, tributaries,
lakes, reservoirs etc.

5. OBJECTIVES OF HYDROLOGY
To obtain data regarding the stream flow of water that
would be available,
 To predict the yearly possible flow
 To calculate the mean annual rainfall in the area under
consideration from a record of the annual rainfall for a
number of years, say 25 to 30
 To note the frequency of dry years
 To find maximum rainfall and flood frequency

6. HYDROGRAPH
 It is a graphical representation between discharge
and time
 shows the variation of stream flow in m3/s with
time for a particular river site. The time may be
hour, week, month or a year.
 The area under hydrograph gives the total volume
of flow

7. Storage:
 to ensure water availability during deficient flow
and thus increasing the firm capacity
 Storage also results in more energy production
Pondage:
 Storing water in small ponds near the power
plant as the storage reservoir is away from plant
 To meet the power demand fluctuations over a
short period of time

8. SITE SELECTION FOR HYDROPOWER PLANTS
 Availability of Water: Run-off data for many years
available
• Water Storage: for water availability throughout the
year
• Head of Water: most economic head, possibility of
constructing a dam to get required head
• Geological Investigations: strong foundation,
earthquake frequency is less
• Water Pollution: excessive corrosion and damage to
metallic structures

9. SITE SELECTION FOR HYDROPOWER PLANTS
• Social and Environmental Effects: submergence
of areas, effect on biodiversity (e.g. western
ghat), cultural and historic aspects
• Access to Site: for transportation of construction
material and heavy machinery new railway lines
or roads may be needed
• Multipurpose: power generation, irrigation,
flood control, navigation, recreation; because
initial cost of power plant is high because of civil
engineering construction work

10. CLASSIFICATION OF HYDRO-ELECTRIC PLANTS
Hydro power plants are classified Based upon
(1) Quantity of water available
(2) Available Head
(3) Nature of load

11. classification of hydro-electric plants According to
water available
A. Run-off River plants Without Pondage
B. Run-off River plants With Pondage
C. Reservoir Plants

12. Run-off river plants without pondage
 It doesn’t store water, It uses water as it comes
 It uses water only when available
 Generating capacity primarily depending on the rate of
flow of water
 During rainy season some quantity of water wasted
without using for the generation of power
 During low run-off periods due to low flow rates , the
generating capacity of plant is low

13. Run-off river plants with pondage
 Usefulness of a run-off river plant is increased by
pondage
 Pondage permits storage of water during the off-peak
periods and use of this water during peak periods
 It is cope up by the size of the pondage
 This plant can be used on parts of the load curve
requirement, within certain limitations
 It is more useful than a plant without pondage or storage

14. RESERVOIR PLANTS
 Majority of the plants are this type.
 It permit carrying over storage from wet season to the
next dry season
 Water is stored behind the Dam and is available to plant
with proper control
 It has better capacity and can be used through out year
 It can be used as a base-load plant or peak load plant as
required
 It can also be used on any portion of the load curve as
required

15. Classification of hydro-electric plants According
to Available Head
a. Low head (2-30m)
b. Medium head (30-70m)
c. High head (71-500m)

16. LOW HEAD PLANTS
 Small dam is built across the river to provide the
necessary head(upto 30m)
 The excess water is allowed to flow over the dam itself
 Used turbines: Francis, Propeller or Kaplan turbine
 No surge tank is required

18. MEDIUM HEAD PLANTS
 Forebay is provided at the beginning of penstock serves
as water reservoir for such plants
 Generally in this plants water carried in open canals from
main reservoir to the forebay and then to the power house
through penstock. The forebay itselfs works as a surge
tank
 Prime mover or Turbines: Francis, Propeller and Kaplan

20. HIGH HEAD PLANTS
 All water is carried from the main reservoir by a tunnel
upto the surge tank and then from surge tank to the
power house through pen stock
 Heads more than 300 m
 Pelton wheel turbine preferred

22. Classification of hydro-electric plants According
to Nature of load
A. Base load plants
B. Peak load plants
C. Pumped-storage plants for peak loads

23. BASE LOAD PLANTS
 Such loads can take up the load on base portion of the
load curve
 In this type plants load is almost constant
 Load factor is high
 Run-off power plants without pondage can be used as
base load plant
 Similarly the plants which has storage also work as base
load plants

24. PEAK-LOAD PLANTS
 Run-off river plants with pondage can be used as peak-
load plants
 Reservoir plants with water storage back side dam may
be used as either base-load plant or peak load plant as
required
 Note: Plants used to supply the peak load of the system
corresponding to the load at the top portion of the load
curve are known as peak-load plants

25. pumped storage plants for peak-load
 Water after passing through the turbine stores in tail-race
pond, Where it may fed back to the head water pond
 Water send from tail-race pond to Head water pond during
off-peak period
 During peak load period water passes from Head water pond
to the penstock to operate the turbines
 It can recover 70% of the power by using pumping water
 By using reversible-turbine-pump unit a turbine can generate
power and a pump while pumping water to storage.
 The generator is worked as a motor during reverse operation
 So that efficiency is high
 The cost of reversible-turbine-pump sets increases
 It meets peak loads

27. COMPONENTS OF HYDRO ELECTRIC POWER
PLANT
The various components of HPP are as follows:
1. Catchment area
2. Reservoir
3. Dam
4. Spillways
5. Conduits
6. Surge tanks
7. Draft tubes
8. Power house
9. Switchyard for power evacuation

28. COMPONENTS OF HYDRO ELECTRIC POWER
PLANT
Dam
Develops a reservoir to store water
Builds up head for power generation
Trash Rack: It is provided to stop the entry of debris. Which
might damage the gates turbine runners or choking of nozzles of the
impulse turbines. It is placed across the intake

29. Spillway
To safeguard the dam when water level in the
reservoir rises

30. COMPONENTS OF HYDRO ELECTRIC
POWER PLANT
Intake
Contains trash racks to filter out debris which may
damage the turbine
Forebay
Enlarged body of water just above the intake

31. INTAKE OR CONTROL GATES
These are the gates built on the inside of the dam. The
water from reservoir is released and controlled through
these gates. These are called inlet gates because water
enters the power generation unit through these gates.
When the control gates are opened the water flows due
to gravity through the penstock and towards the turbines.
The water flowing through the gates possesses potential
as well as kinetic energy.

32. COMPONENTS OF HYDRO ELECTRIC
POWER PLANT
Conduits
Headrace is a channel which lead the water to the turbine
Tailrace is a channel which carries water from the turbine
A canal is an open waterway excavated in natural ground
following its contour.
A tunnel is a closed channel excavated through an obstruction.
A pipeline is a closed conduit supported on the ground.
Penstocks are closed conduits for supplying water “under
pressure” from head pond to the turbines.

33. The Penstock
 The penstock is the long pipe or the shaft that carries the
water flowing from the reservoir towards the power
generation unit, comprised of the turbines and generator.
The water in the penstock possesses kinetic energy due
to its motion and potential energy due to its height.
 The total amount of power generated in the hydroelectric
power plant depends on the height of the water reservoir
and the amount of water flowing through the penstock.
The amount of water flowing through the penstock is
controlled by the control gates.

35. SURGE TANK
A surge tank is a small reservoir in which the water level rises or falls to
reduce the pressure swings so that they are not transmitted to the
penstock.
Water Hammer
 Load on the turbine is suddenly reduced
 Governor closes turbine gates
 Sudden increase of pressure in the penstock
Negative Pressure
 Load on the generator is suddenly increased
 Governor opens the turbine gates
 Tends to cause a vacuum in the penstock
 When the gates are closed, water level rises in the surge tank
and when the gates are suddenly opened, surge tank provides
the initial water supply

37. Draft Tubes
The function of the draft tube is to
To reduce the velocity head losses of the water
To allow the turbine to be set above the tailrace to
facilitate inspection and maintenance

39. Tailrace:
A tailrace is required to discharge the water leaving the
turbine into the river.
The design of the tail race should be such that water has
a free exit.

40. TYPES OF HYDRAULIC TURBINES
1. According to the head and quantity of water
available
a. Low head (2-15m)
b. Medium head (16-70m)
c. High head (71-500m)
d. Very high head (>500m)
2. According to the name of the originator
a. Francis
b. Kaplan
c. Pelton

41. 3. According to the nature of working of water on blades

45. Example:
Find out the specific speed of a turbine of 10 MW capacity
working under a head of 500m and having the normal
working speed of 300 RPM.

46. 4. According to the direction of flow of water
a. Radial
b. Axial
c. Tangential (Deriaz)
5. According to the axis of the turbine shaft:
vertical, horizontal

47. COMPARISON OF TURBINES

48. SWITCHYARD
1. Step up transformers
2. Instrument transformers
3. Transmission lines

49. POWER HOUSE

50. POWER HOUSE
1. Hydraulic turbines
2. Electric generators
3. Governors
4. Gate valves
5. Relief valves
6. Water circulation pumps
7. Air ducts
8. Switch board and instruments
9. Storage batteries
10. Cranes

51. ADVANTAGES OF HYDROELECTRIC ENERGY
1) It is a non-polluting source of energy.
2) It has lower operational cost compared to fossil fuel-based
generation plants.
3) Can be easily transmitted through wires to long distances.
4) Dams made for generation of Hydroelectricity also help in
irrigation projects.

52. DISADVANTAGES
1) It can be generated only in areas with heavy rainfall and
sufficient supply of water.
2) Hydel power generation stations are to be located in hilly
mountainous terrains where waterfalls as well as ideal sites for
dams are located. In a region/country without hills hydel power
generation is not possible.
3) Loss during transmission is very high, sometimes up to 30%.
4) Dams are expensive to build.
5) Building a dam affects the environment and wildlife of
adjoining areas. Nearby low-lying areas are always under the
threat of floods.
6) Building of dam causes lot of pollution.
7) If rains are scarce, there might not be enough water to turn
turbines.

59. https://www.youtube.com/watch?v=Lx6UfiE
U3Q0
http://www.electricalquizzes.com/electric-
power-generation/electric-power-
generation-mcqs-3