Thermal Power Station | Power Systems - Electrical Engineering (EE) PDF Download

 Page 1


 
  
 
Thermal power stations introductions 
 
For generating EMF,the following are essential  
1.Conductor system 
2.Flux liness 
3.Relative motion  
 
Generation of electrical energy: 
 
   
 
Various sources of energy: 
 
1.Sun 
2.Wind 
3.water 
4.Fuel 
5.Nuclear forces 
 
1.Sun:It is the primary source for producing energy.In this the heat radiated from the sun is concentrated 
over a small area by using reflectors & that heat is used to raise the temperature of steam & is passed 
through the prime mover which converts it mechanical energy & that mechanical energy is passed 
through AC generator which converts it to electrical energy.   
 
Limitations:-  
1. Requires large area for generation of small amount of power. 
2. Cannot be used during night times & cloudy days 
3. Un economical 
Page 2


 
  
 
Thermal power stations introductions 
 
For generating EMF,the following are essential  
1.Conductor system 
2.Flux liness 
3.Relative motion  
 
Generation of electrical energy: 
 
   
 
Various sources of energy: 
 
1.Sun 
2.Wind 
3.water 
4.Fuel 
5.Nuclear forces 
 
1.Sun:It is the primary source for producing energy.In this the heat radiated from the sun is concentrated 
over a small area by using reflectors & that heat is used to raise the temperature of steam & is passed 
through the prime mover which converts it mechanical energy & that mechanical energy is passed 
through AC generator which converts it to electrical energy.   
 
Limitations:-  
1. Requires large area for generation of small amount of power. 
2. Cannot be used during night times & cloudy days 
3. Un economical 
 
Wind:-Wind flows for a considerable length of time to run the wind mill which drives a small generator. At 
the time of wind flowing the generator charges the batteries & these batteries will give supply at the time 
when wind is not flowing.     
Water:-It is stored at suitable places to possess potential energy because of head and is very popular 
because of low production & maintenance cost.   
Fuel:- 
Solid form-coal 
Liquid form-oil 
Gaseous form-natural gas 
Here,fuel energy is converted into mechanical energy by the prime movers such as steam 
engines,IC(internal) engines, steam turbine etc & is converted into electrical energy using alternator. 
Nuclear energy:-Large heat is liberated from fissioning of uranium & other nuclear products. 
?Heat liberated by 1 kg of nuclear fuel is equal to that of 4500 tons of coal. 
 
 
Property Water Fuel Nuclear 
Initial cost 
Running cost 
Reserves 
Cleanliness 
Simplicity 
reliability 
High 
Less 
Permanent 
Cleanest 
Simplest 
most 
Low 
High 
Exhaustable 
Dirtiest 
Complex 
less 
Highest 
Least 
In-exhaustible 
Clear 
More complex 
more 
        
 
I. Steam power station (or) Thermal power station 
 
?condensed means steam becomes water 
   
Heat from mechanical  electrical energy 
Coal combustion energy 
?A generating station which conterts heat energy of the coal combustion into electrical energy is known  
  as steam power station. 
?It works on the rankine cycle. Steam is produced in the boiler by receiving the heat from the       
Page 3


 
  
 
Thermal power stations introductions 
 
For generating EMF,the following are essential  
1.Conductor system 
2.Flux liness 
3.Relative motion  
 
Generation of electrical energy: 
 
   
 
Various sources of energy: 
 
1.Sun 
2.Wind 
3.water 
4.Fuel 
5.Nuclear forces 
 
1.Sun:It is the primary source for producing energy.In this the heat radiated from the sun is concentrated 
over a small area by using reflectors & that heat is used to raise the temperature of steam & is passed 
through the prime mover which converts it mechanical energy & that mechanical energy is passed 
through AC generator which converts it to electrical energy.   
 
Limitations:-  
1. Requires large area for generation of small amount of power. 
2. Cannot be used during night times & cloudy days 
3. Un economical 
 
Wind:-Wind flows for a considerable length of time to run the wind mill which drives a small generator. At 
the time of wind flowing the generator charges the batteries & these batteries will give supply at the time 
when wind is not flowing.     
Water:-It is stored at suitable places to possess potential energy because of head and is very popular 
because of low production & maintenance cost.   
Fuel:- 
Solid form-coal 
Liquid form-oil 
Gaseous form-natural gas 
Here,fuel energy is converted into mechanical energy by the prime movers such as steam 
engines,IC(internal) engines, steam turbine etc & is converted into electrical energy using alternator. 
Nuclear energy:-Large heat is liberated from fissioning of uranium & other nuclear products. 
?Heat liberated by 1 kg of nuclear fuel is equal to that of 4500 tons of coal. 
 
 
Property Water Fuel Nuclear 
Initial cost 
Running cost 
Reserves 
Cleanliness 
Simplicity 
reliability 
High 
Less 
Permanent 
Cleanest 
Simplest 
most 
Low 
High 
Exhaustable 
Dirtiest 
Complex 
less 
Highest 
Least 
In-exhaustible 
Clear 
More complex 
more 
        
 
I. Steam power station (or) Thermal power station 
 
?condensed means steam becomes water 
   
Heat from mechanical  electrical energy 
Coal combustion energy 
?A generating station which conterts heat energy of the coal combustion into electrical energy is known  
  as steam power station. 
?It works on the rankine cycle. Steam is produced in the boiler by receiving the heat from the       
  combustion. The steam is then expanded using prime prime mover i.e. steam turbine & is condensed in  
  a condenser to be fed into the boiler again. 
?The steam turbine drives the alternator which converts mechanical energy of the turbine into electrical  
  energy. This type of power station is suitable where coal & water are available in abundance & a large  
  amount of electric power is to be generated. 
Adantages:- 
1. The fuel (coal) used is quite cheap. 
2. Less initial cost as compared to other generating station. 
3. It requires less space as compared to the hydro electric power station. 
4. The cost of generation is lesser than that of diesel power station. 
5. It can be installed at any place irrespective of the existence of coal. 
6. The coal can be transported to the site of the plant by rail or road. 
Disadvantages:-    
1. It pollutes the atmosphere due to the production of large amount of smoke & fumes. 
2. It is costlier in running cost as compared to hydro electric plant. 
 
Schematic arrangement of steam power station:- 
 
 
Page 4


 
  
 
Thermal power stations introductions 
 
For generating EMF,the following are essential  
1.Conductor system 
2.Flux liness 
3.Relative motion  
 
Generation of electrical energy: 
 
   
 
Various sources of energy: 
 
1.Sun 
2.Wind 
3.water 
4.Fuel 
5.Nuclear forces 
 
1.Sun:It is the primary source for producing energy.In this the heat radiated from the sun is concentrated 
over a small area by using reflectors & that heat is used to raise the temperature of steam & is passed 
through the prime mover which converts it mechanical energy & that mechanical energy is passed 
through AC generator which converts it to electrical energy.   
 
Limitations:-  
1. Requires large area for generation of small amount of power. 
2. Cannot be used during night times & cloudy days 
3. Un economical 
 
Wind:-Wind flows for a considerable length of time to run the wind mill which drives a small generator. At 
the time of wind flowing the generator charges the batteries & these batteries will give supply at the time 
when wind is not flowing.     
Water:-It is stored at suitable places to possess potential energy because of head and is very popular 
because of low production & maintenance cost.   
Fuel:- 
Solid form-coal 
Liquid form-oil 
Gaseous form-natural gas 
Here,fuel energy is converted into mechanical energy by the prime movers such as steam 
engines,IC(internal) engines, steam turbine etc & is converted into electrical energy using alternator. 
Nuclear energy:-Large heat is liberated from fissioning of uranium & other nuclear products. 
?Heat liberated by 1 kg of nuclear fuel is equal to that of 4500 tons of coal. 
 
 
Property Water Fuel Nuclear 
Initial cost 
Running cost 
Reserves 
Cleanliness 
Simplicity 
reliability 
High 
Less 
Permanent 
Cleanest 
Simplest 
most 
Low 
High 
Exhaustable 
Dirtiest 
Complex 
less 
Highest 
Least 
In-exhaustible 
Clear 
More complex 
more 
        
 
I. Steam power station (or) Thermal power station 
 
?condensed means steam becomes water 
   
Heat from mechanical  electrical energy 
Coal combustion energy 
?A generating station which conterts heat energy of the coal combustion into electrical energy is known  
  as steam power station. 
?It works on the rankine cycle. Steam is produced in the boiler by receiving the heat from the       
  combustion. The steam is then expanded using prime prime mover i.e. steam turbine & is condensed in  
  a condenser to be fed into the boiler again. 
?The steam turbine drives the alternator which converts mechanical energy of the turbine into electrical  
  energy. This type of power station is suitable where coal & water are available in abundance & a large  
  amount of electric power is to be generated. 
Adantages:- 
1. The fuel (coal) used is quite cheap. 
2. Less initial cost as compared to other generating station. 
3. It requires less space as compared to the hydro electric power station. 
4. The cost of generation is lesser than that of diesel power station. 
5. It can be installed at any place irrespective of the existence of coal. 
6. The coal can be transported to the site of the plant by rail or road. 
Disadvantages:-    
1. It pollutes the atmosphere due to the production of large amount of smoke & fumes. 
2. It is costlier in running cost as compared to hydro electric plant. 
 
Schematic arrangement of steam power station:- 
 
 
 
Although steam power station, simply involves the conversion of heat of coal conversion into electrical 
energy, yet it embraces many arrangements of proper working an efficiency. 
?The schematic arrangement of a modern power station is shown in fig.& the whole arrangement is 
divided into the following stages. 
1. Coal and ash handling arrangement 
2. Steam generating plant 
3. Steam turbine 
4. Alternator 
5. Feed water 
6. Cooling arrangement 
1. Coal & ash handling plant: - The coal is transported to the power station by road on rail & is stored in 
the coal storage plant. Storage of coal is primarily due to protection against coal is primarily due to 
protection against coal strikes, failure of transportation and general coal shortages. From the coal 
storage plant, coal is delivered to the coal handing plant where it is pulverized (i.e. crushing into 
small pieces ) in order to increase its surface exposure for rapid combustion. 
?The pulverized is fed to the failure by belt conveyors. The coal is burnt in the boiler & the ash 
produced is removed to the ash handing plant & then delivered ash storage plant for disposal. The 
removal of the ash from the boiler furnace is necessary for proper burning of coal. 
?In modern thermal station of 100MW a 50% load factor may burn about 20,000 tonnes of coal per 
month & ash produced may be is the range of 10 to 15% of the coal fire i.e. 2000 to 3000 tonnes. In fact 
in a thermal station about 50 to 60% of the total operating cost consists of fuel purchasing & handling. 
2) Steam generating plant:-It consists of a boiler for the production of steam & other auxiliary equipment 
for the utilization of flue gases. 
a) Boiler:-The heat of combustion of coal in the boiler is utilized to convert water into steam at high 
temperature & pressure. The flue gases from the boiler make their journey through super heater, 
economizer, air pre-heater & are finally exhausted to atmosphere through chimney. 
b) Super heater:-The steam produced in the boiler is wet & is passed through a super heater where it is 
dried & super heated (i.e. steam temperature increased above that of the boiling pt.of water) by the flue 
gases in their way to chimney. This super heating provides two benefits.Firstly, the overall efficiency is 
increased.Secondly, too much condensation in the last stages of the turbine is avoided. The super heated 
steam from the super heater is fed to steam turbine through the main valve. 
c) Economizer:-An economizer is essentially a feed water heater and derives heat from flue gases .For 
this purpose. The feed water is fed to the economizer before supplying to the boiler. The economizer 
extracts a part of heat of flue gases to increase the feed water temperature. 
Page 5


 
  
 
Thermal power stations introductions 
 
For generating EMF,the following are essential  
1.Conductor system 
2.Flux liness 
3.Relative motion  
 
Generation of electrical energy: 
 
   
 
Various sources of energy: 
 
1.Sun 
2.Wind 
3.water 
4.Fuel 
5.Nuclear forces 
 
1.Sun:It is the primary source for producing energy.In this the heat radiated from the sun is concentrated 
over a small area by using reflectors & that heat is used to raise the temperature of steam & is passed 
through the prime mover which converts it mechanical energy & that mechanical energy is passed 
through AC generator which converts it to electrical energy.   
 
Limitations:-  
1. Requires large area for generation of small amount of power. 
2. Cannot be used during night times & cloudy days 
3. Un economical 
 
Wind:-Wind flows for a considerable length of time to run the wind mill which drives a small generator. At 
the time of wind flowing the generator charges the batteries & these batteries will give supply at the time 
when wind is not flowing.     
Water:-It is stored at suitable places to possess potential energy because of head and is very popular 
because of low production & maintenance cost.   
Fuel:- 
Solid form-coal 
Liquid form-oil 
Gaseous form-natural gas 
Here,fuel energy is converted into mechanical energy by the prime movers such as steam 
engines,IC(internal) engines, steam turbine etc & is converted into electrical energy using alternator. 
Nuclear energy:-Large heat is liberated from fissioning of uranium & other nuclear products. 
?Heat liberated by 1 kg of nuclear fuel is equal to that of 4500 tons of coal. 
 
 
Property Water Fuel Nuclear 
Initial cost 
Running cost 
Reserves 
Cleanliness 
Simplicity 
reliability 
High 
Less 
Permanent 
Cleanest 
Simplest 
most 
Low 
High 
Exhaustable 
Dirtiest 
Complex 
less 
Highest 
Least 
In-exhaustible 
Clear 
More complex 
more 
        
 
I. Steam power station (or) Thermal power station 
 
?condensed means steam becomes water 
   
Heat from mechanical  electrical energy 
Coal combustion energy 
?A generating station which conterts heat energy of the coal combustion into electrical energy is known  
  as steam power station. 
?It works on the rankine cycle. Steam is produced in the boiler by receiving the heat from the       
  combustion. The steam is then expanded using prime prime mover i.e. steam turbine & is condensed in  
  a condenser to be fed into the boiler again. 
?The steam turbine drives the alternator which converts mechanical energy of the turbine into electrical  
  energy. This type of power station is suitable where coal & water are available in abundance & a large  
  amount of electric power is to be generated. 
Adantages:- 
1. The fuel (coal) used is quite cheap. 
2. Less initial cost as compared to other generating station. 
3. It requires less space as compared to the hydro electric power station. 
4. The cost of generation is lesser than that of diesel power station. 
5. It can be installed at any place irrespective of the existence of coal. 
6. The coal can be transported to the site of the plant by rail or road. 
Disadvantages:-    
1. It pollutes the atmosphere due to the production of large amount of smoke & fumes. 
2. It is costlier in running cost as compared to hydro electric plant. 
 
Schematic arrangement of steam power station:- 
 
 
 
Although steam power station, simply involves the conversion of heat of coal conversion into electrical 
energy, yet it embraces many arrangements of proper working an efficiency. 
?The schematic arrangement of a modern power station is shown in fig.& the whole arrangement is 
divided into the following stages. 
1. Coal and ash handling arrangement 
2. Steam generating plant 
3. Steam turbine 
4. Alternator 
5. Feed water 
6. Cooling arrangement 
1. Coal & ash handling plant: - The coal is transported to the power station by road on rail & is stored in 
the coal storage plant. Storage of coal is primarily due to protection against coal is primarily due to 
protection against coal strikes, failure of transportation and general coal shortages. From the coal 
storage plant, coal is delivered to the coal handing plant where it is pulverized (i.e. crushing into 
small pieces ) in order to increase its surface exposure for rapid combustion. 
?The pulverized is fed to the failure by belt conveyors. The coal is burnt in the boiler & the ash 
produced is removed to the ash handing plant & then delivered ash storage plant for disposal. The 
removal of the ash from the boiler furnace is necessary for proper burning of coal. 
?In modern thermal station of 100MW a 50% load factor may burn about 20,000 tonnes of coal per 
month & ash produced may be is the range of 10 to 15% of the coal fire i.e. 2000 to 3000 tonnes. In fact 
in a thermal station about 50 to 60% of the total operating cost consists of fuel purchasing & handling. 
2) Steam generating plant:-It consists of a boiler for the production of steam & other auxiliary equipment 
for the utilization of flue gases. 
a) Boiler:-The heat of combustion of coal in the boiler is utilized to convert water into steam at high 
temperature & pressure. The flue gases from the boiler make their journey through super heater, 
economizer, air pre-heater & are finally exhausted to atmosphere through chimney. 
b) Super heater:-The steam produced in the boiler is wet & is passed through a super heater where it is 
dried & super heated (i.e. steam temperature increased above that of the boiling pt.of water) by the flue 
gases in their way to chimney. This super heating provides two benefits.Firstly, the overall efficiency is 
increased.Secondly, too much condensation in the last stages of the turbine is avoided. The super heated 
steam from the super heater is fed to steam turbine through the main valve. 
c) Economizer:-An economizer is essentially a feed water heater and derives heat from flue gases .For 
this purpose. The feed water is fed to the economizer before supplying to the boiler. The economizer 
extracts a part of heat of flue gases to increase the feed water temperature. 
d)Air preheater:-An air preheater increases the temperature of the supplied for coal burning by deriving 
air from the atmosphere by a forced draught fan and is passed through an air preheater extracts heat 
from the flue gases and increases the temperature of air used for coal combustion. The principle benefits 
of preheater are to increase thermal efficiency & to increase the steam capacity the square meter of the 
boiler furnace. 
3)Steam turbine:-The dried & super heated steam from the super heater is fed to the steam turbine 
through main valve. The heat energy of the steam when passing over the blades of the turbine is 
converted mechanical energy. After giving heat energy to the turbines, the steam is exhausted to the 
condenser which condenses the exhausted steam by means of cold water circulation. 
Alternator:-The steam turbine is coupled to an alternator. The alternator converts the mechanical energy 
of the turbine to electrical energy. The electrical output from the alternator is delivered to the bus bars 
through transformers circuit breakers and isolators. 
Feed water:-The condensate from the condenser is used as feed water to the boiler. Some water may be 
last in the cycle which is suitably made up from the external source. The feed water on its way to the 
boiler is heated by water heater & economizer. This helps is raising the overall efficiency of the plant. 
Coaling arrangement:-In order to improve the efficiency of the plant, the steam is exhausted from the 
turbine is condensed by means of acondenser.Water is drawn from a natural source of supply such as a 
river, canal or lake & is circulated over the condenser. The circulating water takes up the heat of the 
exhausted steam and itself becomes hot. This hot water coming out from the condenser is discharged at 
a suitable location down the river. In case the availability of water is not assured throughout the year, 
cooling, cooling towers are used. 
?During the scarcity of water in the river hot water from the condenser is passed on to the cooling 
towers where it is cooled. The cold water from the coaling tower is reused in the condenser. 
Selection of sites for steam power station:- Factors affecting the sites selection for thermal power 
station(TPS). 
1. Supply of the fuel:- (TPS) It should be located near the coal mines so that transportation cost of fuel 
is minimum.However,if it is installed anywhere at which coal is not available, care should be taken 
that adequate facilities should exit for the transportion. 
2. Availability of water:-As huge amount of water is required for the condenser, it should be located at 
the bank of a river (or) near to a canal to ensure the continuous supply of water. 
3. Transportation facilities:- The modern station ofter requires the transportation of material & 
machinery.Therefore,adequate transportation facilities must exit i.e.it should well connected to the 
other parts of the country either by road or rail etc. 
4. Cost and type of land:- IT should be located at a place where land is cheap & further extension is 
possible. The bearing of the ground should be adequate so that heavy equipment could be installed.