HYDROPOWER ENGINEERING AND GENERATION STATIONS Notes | EduRev

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: HYDROPOWER ENGINEERING AND GENERATION STATIONS Notes | EduRev

 Page 1


 
 
 
 
 
 
 
Module 
5 
  
HYDROPOWER 
ENGINEERING 
Version 2 CE IIT, Kharagpur 
 
Page 2


 
 
 
 
 
 
 
Module 
5 
  
HYDROPOWER 
ENGINEERING 
Version 2 CE IIT, Kharagpur 
 
 
 
 
 
 
 
LESSON  
3 
 
HYDROPOWER 
EQIUPMENT AND 
GENERATION STATIONS 
 
 
 
Version 2 CE IIT, Kharagpur 
 
Page 3


 
 
 
 
 
 
 
Module 
5 
  
HYDROPOWER 
ENGINEERING 
Version 2 CE IIT, Kharagpur 
 
 
 
 
 
 
 
LESSON  
3 
 
HYDROPOWER 
EQIUPMENT AND 
GENERATION STATIONS 
 
 
 
Version 2 CE IIT, Kharagpur 
 
Instructional objectives: 
 
On completion of this lesson, the student shall learn about: 
 
1. Equipment employed for converting water energy to electrical energy 
2. Different types of turbines 
3. Guidelines for selecting a specific turbine 
4. layout of power houses  
 
5.3.0 Introduction 
 
The powerhouse of a hydroelectric development project is the place where the potential 
and kinetic energy of the water flowing through the water conducting system is transformed 
into mechanical energy of rotating turbines and which is then further converted to electrical 
energy by generators. In order to achieve these functions, certain important equipments are 
necessary that control the flow entering the turbines from the penstocks and direct the flow 
against the turbine blades for maximum efficient utilization of water power. Other 
equipments necessary are couplings to link the turbine rotation to generator and 
transformers and switching equipment to convey the electric power generated to the power 
distribution system.  
A powerhouse also accomodates equipment that are necessary for regular operation and 
maintenance of the turbine and power generating units. For example, overhead cranes are 
required for lifting or lowering ofturbines and generator during installation period or later for 
repair and maintenance. For the crane to run, guide rails on columns are essentially 
required. The maintenance of a unit is done by lifting it by the crane and transporting it to 
one end of the power house where abundant space is kept for placing the faulty unit. A 
workshop nearby provides necessary tools and space for the technicians working on the 
repair of the units.  
A control room is also essential in a powerhouse from where engineers can regulate the 
valves controlling water flow into the turbines or monitor the performance of each unit to the 
main power grid. 
Power houses that receive water from a reservoir through a penstock may be termed as 
power generating units detached from head works. There is another class of powerhouse 
that utilize the water head directly from the water body. These are usually the run-of the 
river type power houses mentioned in Lesson 5.1, which are located as a part of a barrage 
in a river or those which utilize the head difference of a canal fall. 
The detached power houses may be surface or underground types depending upon its 
position with respect to the ground surface. In-stream or run-of-river power houses are 
mostly surface type. 
Turbines are of different types like reaction or impulse-types. They may also be divided as 
with horizontal or vertical axes. This lesson discusses all the salient features of a 
Version 2 CE IIT, Kharagpur 
 
Page 4


 
 
 
 
 
 
 
Module 
5 
  
HYDROPOWER 
ENGINEERING 
Version 2 CE IIT, Kharagpur 
 
 
 
 
 
 
 
LESSON  
3 
 
HYDROPOWER 
EQIUPMENT AND 
GENERATION STATIONS 
 
 
 
Version 2 CE IIT, Kharagpur 
 
Instructional objectives: 
 
On completion of this lesson, the student shall learn about: 
 
1. Equipment employed for converting water energy to electrical energy 
2. Different types of turbines 
3. Guidelines for selecting a specific turbine 
4. layout of power houses  
 
5.3.0 Introduction 
 
The powerhouse of a hydroelectric development project is the place where the potential 
and kinetic energy of the water flowing through the water conducting system is transformed 
into mechanical energy of rotating turbines and which is then further converted to electrical 
energy by generators. In order to achieve these functions, certain important equipments are 
necessary that control the flow entering the turbines from the penstocks and direct the flow 
against the turbine blades for maximum efficient utilization of water power. Other 
equipments necessary are couplings to link the turbine rotation to generator and 
transformers and switching equipment to convey the electric power generated to the power 
distribution system.  
A powerhouse also accomodates equipment that are necessary for regular operation and 
maintenance of the turbine and power generating units. For example, overhead cranes are 
required for lifting or lowering ofturbines and generator during installation period or later for 
repair and maintenance. For the crane to run, guide rails on columns are essentially 
required. The maintenance of a unit is done by lifting it by the crane and transporting it to 
one end of the power house where abundant space is kept for placing the faulty unit. A 
workshop nearby provides necessary tools and space for the technicians working on the 
repair of the units.  
A control room is also essential in a powerhouse from where engineers can regulate the 
valves controlling water flow into the turbines or monitor the performance of each unit to the 
main power grid. 
Power houses that receive water from a reservoir through a penstock may be termed as 
power generating units detached from head works. There is another class of powerhouse 
that utilize the water head directly from the water body. These are usually the run-of the 
river type power houses mentioned in Lesson 5.1, which are located as a part of a barrage 
in a river or those which utilize the head difference of a canal fall. 
The detached power houses may be surface or underground types depending upon its 
position with respect to the ground surface. In-stream or run-of-river power houses are 
mostly surface type. 
Turbines are of different types like reaction or impulse-types. They may also be divided as 
with horizontal or vertical axes. This lesson discusses all the salient features of a 
Version 2 CE IIT, Kharagpur 
 
hydropower generating station including the layout, structural components and mechanical 
parts. 
 
 
5.3.1 Hydraulic turbines 
 
These form the prime mover which transforms the energy of water into mechanical energy 
of rotation and whose prime function is to drive a hydroelectric generator. The turbine 
runner and the rotor of the generator are usually mounted on the same shaft, and thus the 
entire assembly is frequently referred to as the turbo-generator. 
Hydroelectric plants utilize the energy of water falling through a certain difference in levels 
which may range from a few meters to 1500m or even 2000m. To handle such a wide 
range of pressure heads, various turbines differing in design of their working is employed. 
Modern hydraulic turbines are divided into two class - impulse and reaction. An impulse 
turbine is one in which the driving energy is supplied by the water in kinetic form, and a 
reaction turbine is one in which the driving energy is provided by the water partly in kinetic 
and partly in pressure form. The basic types of impulse and reaction turbines are given in 
the following table. 
 
 
   Turbine types       Class Head range 
Propeller turbines:  
Fixed blade 
turbines 
Adjustable blade ( 
Kaplan turbine) 
    
    Reaction 
 
    Reaction 
         
     10-60m 
 
     10-60m 
Diagonal flow turbines 
 
    Reaction      50-150m 
Francis turbine     Reaction     30-400m (even up to 
     500 to 600m)  
Pelton turbine 
 
    Impulse    Above 300m 
 
Each turbine has a water passageway which incorporates a turbine casing, stay vanes for 
support, wicket gates for flow control, a runner that rotates the generator, and a draft tube 
or the exit channel downstream of the turbine. 
 
Figure1 shows the typical positioning of a reaction and impulse turbines with respect to the 
incoming water conducting system and the draft tube, which is the exiting duct of the 
flowing water.  
 
Version 2 CE IIT, Kharagpur 
 
Page 5


 
 
 
 
 
 
 
Module 
5 
  
HYDROPOWER 
ENGINEERING 
Version 2 CE IIT, Kharagpur 
 
 
 
 
 
 
 
LESSON  
3 
 
HYDROPOWER 
EQIUPMENT AND 
GENERATION STATIONS 
 
 
 
Version 2 CE IIT, Kharagpur 
 
Instructional objectives: 
 
On completion of this lesson, the student shall learn about: 
 
1. Equipment employed for converting water energy to electrical energy 
2. Different types of turbines 
3. Guidelines for selecting a specific turbine 
4. layout of power houses  
 
5.3.0 Introduction 
 
The powerhouse of a hydroelectric development project is the place where the potential 
and kinetic energy of the water flowing through the water conducting system is transformed 
into mechanical energy of rotating turbines and which is then further converted to electrical 
energy by generators. In order to achieve these functions, certain important equipments are 
necessary that control the flow entering the turbines from the penstocks and direct the flow 
against the turbine blades for maximum efficient utilization of water power. Other 
equipments necessary are couplings to link the turbine rotation to generator and 
transformers and switching equipment to convey the electric power generated to the power 
distribution system.  
A powerhouse also accomodates equipment that are necessary for regular operation and 
maintenance of the turbine and power generating units. For example, overhead cranes are 
required for lifting or lowering ofturbines and generator during installation period or later for 
repair and maintenance. For the crane to run, guide rails on columns are essentially 
required. The maintenance of a unit is done by lifting it by the crane and transporting it to 
one end of the power house where abundant space is kept for placing the faulty unit. A 
workshop nearby provides necessary tools and space for the technicians working on the 
repair of the units.  
A control room is also essential in a powerhouse from where engineers can regulate the 
valves controlling water flow into the turbines or monitor the performance of each unit to the 
main power grid. 
Power houses that receive water from a reservoir through a penstock may be termed as 
power generating units detached from head works. There is another class of powerhouse 
that utilize the water head directly from the water body. These are usually the run-of the 
river type power houses mentioned in Lesson 5.1, which are located as a part of a barrage 
in a river or those which utilize the head difference of a canal fall. 
The detached power houses may be surface or underground types depending upon its 
position with respect to the ground surface. In-stream or run-of-river power houses are 
mostly surface type. 
Turbines are of different types like reaction or impulse-types. They may also be divided as 
with horizontal or vertical axes. This lesson discusses all the salient features of a 
Version 2 CE IIT, Kharagpur 
 
hydropower generating station including the layout, structural components and mechanical 
parts. 
 
 
5.3.1 Hydraulic turbines 
 
These form the prime mover which transforms the energy of water into mechanical energy 
of rotation and whose prime function is to drive a hydroelectric generator. The turbine 
runner and the rotor of the generator are usually mounted on the same shaft, and thus the 
entire assembly is frequently referred to as the turbo-generator. 
Hydroelectric plants utilize the energy of water falling through a certain difference in levels 
which may range from a few meters to 1500m or even 2000m. To handle such a wide 
range of pressure heads, various turbines differing in design of their working is employed. 
Modern hydraulic turbines are divided into two class - impulse and reaction. An impulse 
turbine is one in which the driving energy is supplied by the water in kinetic form, and a 
reaction turbine is one in which the driving energy is provided by the water partly in kinetic 
and partly in pressure form. The basic types of impulse and reaction turbines are given in 
the following table. 
 
 
   Turbine types       Class Head range 
Propeller turbines:  
Fixed blade 
turbines 
Adjustable blade ( 
Kaplan turbine) 
    
    Reaction 
 
    Reaction 
         
     10-60m 
 
     10-60m 
Diagonal flow turbines 
 
    Reaction      50-150m 
Francis turbine     Reaction     30-400m (even up to 
     500 to 600m)  
Pelton turbine 
 
    Impulse    Above 300m 
 
Each turbine has a water passageway which incorporates a turbine casing, stay vanes for 
support, wicket gates for flow control, a runner that rotates the generator, and a draft tube 
or the exit channel downstream of the turbine. 
 
Figure1 shows the typical positioning of a reaction and impulse turbines with respect to the 
incoming water conducting system and the draft tube, which is the exiting duct of the 
flowing water.  
 
Version 2 CE IIT, Kharagpur 
 
 
 
For the reaction type of turbine, (Figure 1a), the turbine section is assumed to begin at the 
entrance to the turbine case (section A-A in the figure) and end at the exit from the draft 
tube (section B-B). It may be noted that this setting for a reaction turbine ensures the 
following characteristics: 
1. The wheel passage remains completely filled with water 
2. The water acting on the wheel vanes is under pressure greater than atmospheric 
3. The water enters all round the periphery of the wheel through the scroll case 
4. Energy in the form of both pressure and kinetic is utilized by the wheel 
In the Figure1, H
t 
is the head of water on the turbine and is the difference in water specific 
energy between beginning and end of the turbine section. 
For the impulse type turbine (Figure1b), the following characteristics of the turbine setting 
differentiates it from the impulse type of turbines: 
1. The wheel passages are not completely filled with water since a jet emanating from 
the penstock nozzle strikes the buckets of the runner 
2. The water acting on the vanes or buckets located at the wheel periphery is under 
atmospheric pressure 
3. The water impacts on the runner at one point or at a few discrete points, depending 
upon the number of nozzles 
Version 2 CE IIT, Kharagpur 
 
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