This document provides an overview of hydel power plants. It begins with an introduction explaining how hydel power plants convert the kinetic energy of falling water into electricity. It then discusses the history of hydel power, from ancient water wheels to modern hydroelectric plants. The working principles and typical layout of a hydel plant are explained, including components like the reservoir, dam, penstock, turbine, generator and tailrace. Hydel plants are classified based on head of water. The main turbines - Pelton, Francis and Kaplan - are depicted in diagrams. Advantages include renewability while disadvantages include high initial costs and variable power production. In conclusion, hydel power is encouraged with environmental impacts weighed against development needs.

1. HYDEL POWER
PLANT
SUBMITED BY
V.ILLAYARAJA
1

2. CONTENTS
• INTRODUCION
• HISTORY OF HYDEL POWER PLANT
• WORKING PRINCIPLE
• DIAGRAM
• LAYOUT OF HYDEL POWER PLANT
• CLASSIFICATIONS
• TURBINES DIAGRAMS
• ADVANTAGES
• DISADVANTAGES
• CONCLUSION
• REFERENCES
2

3. INTRODUCTION
• Hydroelectric power plants convert the kinetic energy contained in
falling water into electricity. The energy in flowing water is
ultimately derived from the sun, and is therefore constantly being
renewed. Energy contained in sunlight evaporates water from the
oceans and deposits it on land in the form of rain. Differences in
land elevation result in rainfall runoff, and allow some of the
original solar energy to be captured as hydroelectric power
• Hydropower is currently the world's largest renewable source of
electricity, accounting for 6% of worldwide energy supply or about
15% of the world's electricity. Figure 1 shows a ranking of top
hydro generating counties. Traditionally thought of as a cheap and
clean source of electricity, most large hydro-electric schemes
being planned today are coming up against a great deal of
opposition from environmental groups and native people.
3

4. HISTORY OF HYDEL POWER
PLANT
• - Nearly 2000 years ago the Greeks used water wheels to
grind wheat into flour
• - In the 1700's, hydropower was broadly used for milling of
lumber and grain and for pumping irrigation water
• - Appleton, Wisconsin became the first operational
hydroelectric generating station in the United States, in 1882,
producing 12.5 kilowatts (kW) of power
• - The total electrical capacity generated was equivalent to 250
lights
• - Within the next 20 years roughly 300 hydroelectric plants
were operational around the world
• - The invention of the hydraulic reaction turbine created the
sudden expansion of hydropower
• - 40% of the United States' electricity was provided by
hydroelectric power in the early 1900's
4

5. Hydro electric (Hydel) Power Plant
• Working principle
• Potential energy is the energy
which a substance has due to
its position or state. The water
behind a dam has potential
energy because of its position.
The water can fall from this
position and exert a force over
a distance and therefore do
work.
• In a Hydro-electric power plant
the force is used to drive a
turbine, which inturn drives the
electric generator.
• Because gravity provides the
force which makes the water
fall, the energy stored in the 5
water is called gravitational

6. 6

7. 7

8. 8

9. Layout of Hydro electric power plant
• Water reservoir:
• 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.
• Dam :
• 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 9
available.

10. Layout of Hydro electric power
plant…
• Spillway:
• 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.
• Gate :
• A gate is used to regulate or
control the flow of water from the
dam.
• Pressure tunnel:
• It is a passage that carries water
from the reservoir to the surge
tank.
10

11. Layout of Hydro electric power
plant…
• 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 :
• The water hammer is defined as the
change in pressure rapidly above or
below normal pressure caused by 11
sudden change in the rate of water

12. Layout of Hydro electric power
plant…
• Penstock:
• Penstock is a closed pipe of steel
or concrete for supplying water
under pressure to the turbine.
• Inlet valve :
• Water from the penstock flows to
the turbine through the inlet valve.
The valve may be partially closed or
open thereby regulating the
pressure of water flowing to the
turbine.
• Hydraulic turbine(Prime mover) :
• The hydraulic turbine converts the
energy of water into mechanical
energy. The mechanical
energy(rotation) available on the
turbine shaft is coupled to the shaft
of an electric generator and
electricity is produced. The water
after performing the work on turbine
blades is discharged through the
draft tube. 12
• The prime movers which are in

13. Layout of Hydro electric power
plant…
• Draft tube:
• It is connected to the outlet of the turbine.
• It allows the turbine to be placed above the tail
water level.
• Tail water level or Tail race:
• 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.
13

14. Classification of Hydro electric powe
plants
• Hydro –electric power plants are usually classified according to the
available head of water.
High head power plants : Head of water is more than
500 metres. The turbine used in such plants is Pelton wheel.
Medium head power plants : Head of water ranges
from 80 to 500 metres. The
turbine used in such plants is Francis turbine.
Low head power plants : Head of water ranges from
1.5 to 80 metres. The
turbine used in such plants is Kaplan turbine and
Francis turbine.
14

15. Pelton wheel or Pelton turbine
15

16. Francis turbine
16

17. Kaplan turbine
17

18. Advantages of hydel
power plant
• Water is a renewable energy source.
• Maintenance and operation charges are very low.
• The efficiency of the plant does not change with age.
• In addition to power generation, hydro-electric power plants are
also useful for flood control, irrigation purposes, fishery and
recreation.
• Have a longer life(100 to 125 years) as they operate at
atmospheric temperature.
• Water stored in the hydro-electric power plants can also be
used for domestic water supply.
• Since hydro-electric power plants run at low speeds(300 to 400
rpm) there is no requirement of special alloy steel construction
materials or specialised mechanical maintenance.
18

19. Hydro electric (Hydel) Power Plant…
• Disadvantages of hydel power plant :
• The initial cost of the plant is very high.
• Since they are located far away from the load centre, cost of
transmission lines and transmission losses will be more.
• During drought season the power production may be reduced
or even stopped due to insufficient water in the reservoir.
• Water in the reservoir is lost by evaporation.
19

20. CONCLUSION
• Should hydroelectric power be encouraged? I believe the answer to be a
• cautious ‘Yes’.
• Weighing up the benefits and environmental disadvantages is difficult. Until
• recently, projects deemed to be for ‘the greater good’ of the country were
• carried out regardless of the local human and environmental cost. This has
• changed recently, but it is still very difficult to balance. For example, Egypt’s
• communities have benefited from receiving electricity, yet the effect of building
• the Aswan dam has been to starve the farming communities of nutrient-rich silt
• that used to be brought down on the floods each year.
• The benefits of electricity are undisputable for both economic and social
• development, and if the balance is between providing electricity that reduces
• the human mortality rate and protecting the environment, the former must be
• chosen. To choose the latter is arrogance on our part, sitting in well-lit comfy
• buildings, legislating for an effect that will never harm us.
• The theoretical amount of hydroelectric power available world-wide is about four
• times more than has been exploited at the present time (Lamark et al., 1998). It
• is clear that the actual amount of hydroelectricity generated will be much less
• than this total, due to the growing anxiety about environmental costs and the
• economic cost of developing many of these sites.
• Although it is feasible for large scale hydroelectric power projects to be
• developed I do not believe this to be desirable because of the huge
• environmental impact. However an increase in SHP schemes should be
• encouraged to meet local needs.
20

21. REFERENCES
• Diesendorf, M. (2004) "Comparison of employment potential of the coal
and
• wind power industries" Int. J. Environment, Workplace, and Employment,
• 1, 82-90.
• Fearnside, P. M. (2002) "Greenhouse Gas Emissions from a Hydroelectric
• Reservoir (Brazil's Tucurua Dam) and the Energy Policy Implications"
• Water, Air, & Soil Pollution, 133, 69-96.
• Fearnside, P. M. (2004) "Greenhouse Gas Emissions from Hydroelectric
Dams:
• Controversies Provide a Springboard for Rethinking a Supposedly
• "Clean" Energy Source." Climatic Change, 66, 1-8.
• Graham-Rowe, D. (2005) In New Scientist.
• Hoey, J. and Postl, B. (1998) "Determinants -- and determination" CMAJ,
158,
• 1467-1468.
• IHA. 2003. Greenhouse Gas Emissions from Reservoirs. International
• Hydropower Association
21

22. THANK YOU
22