Electrical Power Generation, Transmission and Distribution Explained

ELECTRICAL POWER
GENERATION, TRANSMISSION
AND DISTRIBUTION
KN. Chandrabose
Asst.Professor
EEE Dept. GEC
Sunday, August 05, 2012 1KN. Chandra Bose, Asst. Professor, GECT

Over View of Syllabus
Objectives:
 To understand the various energy sources.
 To understand about transmission and Distribution
schemes.
 To evaluate the performance of power system.

Sources
• Power generated is the compliments of our
natural resources.
• Renewable and Non‐renewable.
– A renewable resource is a natural resource with the
ability to reproduce through biological or natural
processes and replenished with the passage of time.
Renewable resources are part of our natural
environment and form our eco‐system.
– Solar radiation, tides, winds, geothermal, biomass and other natural
elements.

Sources cntd…
• Power generated is the compliments of our
natural resources.
• Non‐renewable.
– Nonrenewable energy‐Energy that is impossible to re‐
make.
– Natural resources such as coal, petroleum (crude oil)
and natural gas take thousands of years to form
naturally and cannot be replaced as fast as they are
being consumed.

Sources cntd…
• Eventually natural resources will become too
costly to harvest and humanity will need to find
other sources of energy.
• Natural gas is a mixture of gases, the most
common being methane (CH4). It also contains
some ethane (C2H5), propane (C3H8), and
butane (C4H10).

MODULE ‐ 1
 Hydro electric
 Thermal
 Diesel
 Nuclear
 Solar
 Wind
 Tidal
 MHD
 Geothermal
 Fuel cells
 CONVENTIONAL SOURCES OF
ENERGY
 NON‐CONVENTIONAL
SOURCES OF ENERGY

MAIN GOAL:
 To provide an adequate and efficient natural
source of energy without burning of fossil fuels.
 To harness the energy of moving water.
 To provide a cheap source of energy.

CONVENTIONAL SOURCES OF ENERGY
Hydro electricity:
• Hydro‐electric power is the power from the
energy of falling water.
• Hydro‐electric plant is the power plant utilizing
the potential energy of water at a height.
• Most widely used form of renewable energy and
is produced in about 150 countries.
• Accounting for 16% of global electricity consumption,
and 3,427 terawatt‐hours of electricity production in
2010.

CONVENTIONAL SOURCES OF ENERGY …
• Asia‐Pacific region generating 32% of global hydropower
in 2010.
• China is the largest hydroelectricity producer, with 721
terawatt‐hours of production in 2010, representing
around 17 percent of domestic electricity use.
• There are now three hydroelectricity plants larger than
10 GW: the
1. Three Gorges Dam in China (22.5 billion kilowatts)
2. Itaipu Dam in Brazil (14 billion kilowatts) and
3. Guri Dam in Venezuela (10.2 Billion Kilo Watts)

• Reasons for extensive development of water power.
– Tremendous increase in demand of electricity
– High cost of fuels
– Limited resources
– Projects are multipurpose
• India has hydel potential of 600 billion units of firm
annual energy.
• Only 23% of this has been utilized so far.

• The average cost of electricity from a hydro plant, larger
than 10 megawatts is 3 to 5 U.S. cents per kilowatt‐hour.
• The water flowing in the river possesses two type of
energy: the kinetic energy due to flow of water and
potential energy due to the height of water.
• In hydroelectric power plant, potential energy of water is
utilized to generate electricity.
• The total power that can be generated from water in
hydroelectric power plant is
Where w – specific wt of water in kg/m3 , Q – rate of flow of water in m3/s,
H – Height of fall in meter's , – overall efficiency

• In hydro‐electric power station, water head is created by
constructing dam across a river.
Factors to be considered:‐ before a project site is
considered.
– Capital cost of plant
– Capital cost of erecting and maintaining the transmission lines,
and annual energy loss in transformation and transmission of
power.
– Energy generation cost compared with those in case of steam,
oil or gas plants, which can be conveniently set up near the load
centre.

SELECTION OF SITE (HYDRO‐ELECTRIC PLANT):
• Select site with natural storage and with large catchment
area.
• High average rain fall, steep gradients, and suitable place
for constructing reservoir.
FACTORS TO BE CONSIDERED:
1. Availability of water: ‐
– Potential energy of water fall or kinetic energy of flowing
stream is utilized for generation of power.
– Hence station should construct based on availability of
water head.

– Estimation of availability of energy from a stream or river
is estimated on the discharge flow and its variation with
time over a number of years.
2. Water storage:
– Storage of water in a suitable reservoir at a height is
essential in order to have continuous supply during dry
season.
– A careful study of geology and topography of the
catchment area is required, before the construction of
dam.
3. Water Head:
– Water head depends on the topography of the area.
– Availability of head has considerable effect on the cost and
economy of power generation.Sunday, August 05, 2012 14KN. Chandra Bose, Asst. Professor, GECT

4. Distance from load centre:
– Distance to be considered for economical transmission of
power.
5. Accessibility of the site:
– Adequate transportation facilities must be available.
6. Water pollution:
– Polluted water must be eliminated from the site.
– Pollution may cause excessive corrosion and damage to the
metallic structures.
7. Sedimentation:
– Gradual deposition of silt may reduce the capacity of reservoir.
– Which may cause damage of turbine blades.

• 8. Large catchment area:
– Must have large catchment area, so that level of water in the
reservoir may not fall below the minimum.
• 9. Availability of land:
– Available land should be cheap in cost.
– Rocky in order to withstand the weight of water, large buildings
and machinery.

How it Works:
 Build a dam on a large river that has a large drop
in elevation.
 The dam stores lots of water behind it in the
reservoir.
 Near the bottom of the dam wall, there is a water
intake.
 Gravity causes it to fall through the penstock
inside the dam.
 At the end of the penstock, there is a turbine
propeller which is turned by the moving water.

 The shaft from the turbine goes up into the
generator, which rotates the armature, producing
power.
 Power lines are connected to the generator that carry
electricity.
 The water continues past the propeller through the
tail‐race into the river past the dam.

Sunday, August 05, 2012 19
ELEMENTS OF HYDRO PLANT
1. STORAGE RESERVOIR
2. DAM
3. FOREBAY
4. SPILLWAY
5. INTAKE
6. SURGE TANK
7. PENSTOCK
8. VALVES AND GATES
9. TRASH RACKS
10. TAIL RACE
11. DRAFT TUBES
12. PRIME MOVERS/ WATER TURBINES
KN. Chandra Bose, Asst. Professor, GECT

1. STORAGE RESERVOIR
– Purpose is to store water during excess flow.
– Can be of natural and artificial.
– Natural reservoir is in the form of lake in high
mountains with large storing capacity.
– Capacity of reservoir depends on the difference
between run‐offs during high and lean (dry) flows.
2. DAM
– Function of dam is not only to raise the water
head, but also to provide the pondage, storage or
the facility of diversion into conduits.

– Dam is the most expensive and important part of
hydro project.
– Built of concrete, earth or rock fill.
– Choice of dam depends upon the foundation
condition, local materials and transportation
availability, occurrence of earth quakes and other
hazards.
– Concrete or masonry dams are of three types:
• Solid gravity
• Buttress
• Arch dam

– Solid gravity dam:
• Made of concrete and suitable for most sites.
• Height of dam cannot be very high, depends on the
strength of subsoil.
– Arch dam:
• It is a curved dam and transmits a major portion of its
water pressure horizontally to the abutments by arch
action.
• Arch dam is preferred, where eve a narrow canyon
width is available.
• It has inherent stability against sliding.

• Buttress dam:
– Buttress/deck dam has inclined up stream face.
– So that water pressure creates a large downward
force, provides stability against over turning or sliding.
3. FOREBAY
– Mainly forebay provided before the Penstock, acts as
water reservoir for medium head plants.
– Serves as a regulating reservoir storing water
temporarily during light load period.
– Provides same for initial increase on account of
increasing load.
– Mainly forebay provided before the Penstock, acts as
water reservoir for medium head plants.

• 4. SPILLWAY
– Act as a safety valve.
– A spillway is located at the top of the reservoir pool.
– Dams may also have bottom outlets with valves or
gates which may be operated to release flood flow.
– Two main types of spillways: controlled and
uncontrolled.
• A controlled spillway has mechanical structures or gates
to regulate the rate of flow.
• An uncontrolled spillway, in contrast, does not have gates;
when the water rises above the lip or crest of the spillway
it begins to be released from the reservoir.

5. INTAKE
– A penstock is a sluice or gate or intake structure that
controls water flow, or an enclosed pipe that delivers
water to hydraulic turbines.
– Intake structures are of two, High Pressure and small
pressure.
6. SURGE TANK
– Surge tanks are usually provided in high or medium‐
head plants.
– The main functions of the surge tank are:
• 1. When the load decreases, the water moves backwards
and gets stored in it.
• 2. When the load increases, additional supply of water
will be provided by surge tank.KN. Chandra Bose, Asst. Professor, GECT

– Change in load creates a very high pressure in the
penstock.
– Results in water hammer phenomenon, which may
leads to penstock bursting.
– Surge Tanks are placed near to the Turbine.
– The Height of Surge Tank is generally kept above the
maximum Water Level in the supply Level Reservoir.
• There are three important types of Surge Tanks used in
Hydro Electric Power Plant.
01)Simple Surge Tank
02)Restricted Orifice type Surge Tank
03)Differential Surge Tank.

– simple surge tank is of uniform cross section and is
open to atmosphere.
– Directly connected to penstock.
– Large in size with expensive proportions and sluggish.
– Not common in common practice.
– Restricted orifice surge tank is more efficient and
economical.
– Drawback is the sudden creation of accelerating and
retarding heads in the conduits, results in proportional
sudden fluctuations on the turbine.
– Differential surge tank is the best suited for practical
case.

7. PENSTOCK
– A closed conduit for carrying water to turbine.
– Penstocks are built of steel or reinforced concrete.
– Thickness must be adequate to withstand the
pressure.
8. Valves and gates
– Control the flow of water into turbine.

9. TRASH RACKS
– Built up from long, flat bars set vertically spaced in
accordance with minimum width of water passage
through the turbine.
– Prevent the ingress of floating and other material to
the turbine.
10. TAIL RACE
– Tail race is the path through which water is pumped
out of the hydro power plant after power generation.
11. Draft Tubes
– An air tight pipe of suitable diameter attached to the
runner outlet and conducting water down from the
wheel.

12. PRIME MOVERS/ WATER TURBINES
– Hydro plants uses water turbine as prime movers.
– Converting one form of energy into other.
– Turbines are of mainly three types
• Pelton wheel ‐ Impulse type
• Francis turbine ‐ Radial Flow
• Kaplan turbine ‐ Axial Flow
– Pelton wheel is an impulse turbine, suited for high head
and low flow plants
– Francis turbine is a reaction turbine, suited for medium
head and medium flow plants.
– Kaplan is a special type of propeller turbine having
adjustable blades and suited for low head and high flow
plants.

• Hydro‐electric Generator
– A low‐speed generator driven by water turbines.
– Hydrogenerators may have a horizontal or vertical
shaft.
– The horizontal units are usually small with speeds of
300–1200 revolutions per minute (rpm).
– The vertical units are usually larger and more easily
adapted to small hydraulic heads. The rotor
diameters range from 2 to 62 ft (0.6 to 19 m) and
capacities from 50 to 900,000 kVA.

Hydro‐electric Generator cntd…
– The generators are rated in kVA (kilovolts times
amperes).
– The normal power‐factor rating of small synchronous
generators is between 0.8 and 1.0 with 0.9 being
common.
– For large generators a rating of 0.9–0.95 is common
with the machines able to operate up to 1.0 when
the load requires.
– Fields are connected in series, supplied from a dc
source at 110/220/300 V.

– Recent generators uses static excitation system.

KERALA PROJECTS:
• KSEB has 23 Hydro Electric Projects, two Diesel power
plants and one Wind Farm . The total installed capacity
is 2229.6 MW. They are
• Hydro Electric Projects (1940.2MW)
– Idukki (780MW)
– Sabarigiri (335MW)
– Idamalayar (75MW)
– Sholayar (54MW)
– Pallivasal (37.5MW)
– Kuttiyadi (225MW)
– Panniar (30MW)
– Neriamangalam (77.65MW)
– Lower Periyar (180MW)
– Poringalkuthu & PLBE (48MW)
– Sengulam (48MW)
– Kakkad (50MW)KN. Chandra Bose, Asst. Professor, GECT

• Small Hydro Electric Projects(52.85MW)
– Kallada (15MW)
– Peppara (3MW)
– Malankara (10.5MW)
– Madupatty (2MW)
– Malampuzha (2.5MW)
– Lower Meenmutty (3.5MW)
– Chembukadavu ‐ 1 (2.7MW)
– Chembukadavu ‐ 2 (3.7MW)
– Urumi ‐1 (3.75MW)
– Urumi ‐2 (2.4MW)
– Kuttiyadi Tail Race (3.75MW)
• Thermal Projects (234.6MW)
– Brahmapuram Diesel Power Plant (106.6MW)
– Kozhikode Diesel Power Plant (128MW)
• Non‐conventional energy (2MW)
– Kanjikode Wind Farm (2MW)

Biggest Kerala project: (An Over view)
• The 'Idukki Dam' ‐ Asia's biggest Arch Dam of 555
feet height.
• Between the two mountains ‐ 'Kuravanmala' (839
meters) and 'Kurathimala' (925 meters ).
• Consists of three major dams.
• Idukki Dam was commissioned in 1976.
• Thickness of 19.81 m, at the deepest foundation &
7.62 m at top.
• Power House is located at Moolamattom which is
about 43 kms away from Idukki.

• A single reservoir spread over 36 miles on a
height of 2300 ft. m.s.l.
• falls through a drop of about 669.2 metres
(2195 feet) to the underground power.
• The Idukki Project was completed with the
economic and technological assistance of
Canada in accordance with the Colombo Plan of
Commonwealth Countries.
• Turbines, 6 x 130 MW Pelton‐type.
• Technically, the dam type is a concrete double,
curvature parabolic, thin arc.KN. Chandra Bose, Asst. Professor, GECT

•

Hydro Electric Projects of Kerala under KSEB
• Pallivasal Hydro Electtic Project‐ Dams‐Kandla,Madupetty River‐Palar/Periyar
• Sengulam HEP‐ Shengulam Dam River‐Mudriapuzha/Periyar
• Neriyamangalam HEP‐ Kallarkutty Dam River‐Mudriapuzha/Periyar
• Panniyar HEP‐ Dams‐Ponmudi,Anayirangal Rivers‐ Panniar/Periyar
• Idukki HEP‐ Dams‐ Idukki,Cheruthoni,Kulamavu Rivers‐ Periyar, Cheruthoni/Periyar, Kilivillithode
• Idukki Augmentation‐ Dams‐ Kallar, Erattayar, Azhutha, Vadakkepuzha, Vazhikkadavu Rivers‐
Perinjankutty/Periyar,Perinjankutty, Periyar..
• ldamalayar HEP‐ Idamalayar Dam‐ Rivers‐ldamalayar/Periyar
• Lower Periyar HEP‐ Dam‐ Lower Periyar‐ River‐Periyar
• Poringalkuttu HEP‐ Dam‐Poringalkuttu‐ River‐ Chalakudy
• Sholayar HEP‐ Dams‐ Sholayar‐Main Dam,Sholayar‐Flanking,Sholayar‐ Saddle Dam River‐
Chalakudy
• Sabarigiri HEP‐ Dams‐Kakki,Anathodu,Pampa Rivers‐ Kakki/Pamba, Anathodu/Pamba,Pampa
• Sabarigiri Augmentation‐ Dams‐ Upper Moozhiyar, Gavi, Kallar, Meenar I,Meenar II Rivers‐
Moozhiyar/Pamba,Gavi Ar/Pamba, Kallar/Pamba, Minar/Pamba, Minar/Pamba
• Kakkad HEP‐ Dams‐Veluthodu, Moozhiyar Rivers‐ Veluthodu/Pamba, Moozhiyar/Pamba
• Kuttiyadi HEP‐ Dams‐Kuttiyadi River‐Kuttiyadi
• Kuttiyadi Augmentation‐ Dams‐ Kuttiyadi Augn, Kosani Saddle,Near Kottagiri Saddle, Kottagiri
Saddle,Kuttiyadi Saddle River‐ Karamanthodu/KabaniKN. Chandra Bose, Asst. Professor, GECT

• Sizes and capacities of hydroelectric facilities

•Major Hydro‐electric Plants

Position of Country in hydro‐ generation

THERMAL POWER PLANT

Thermal ENERGY …
• A thermal power station is a power plant in which the
prime mover is steam driven.
• Water is heated, turns into steam and spins a steam
turbine which drives an electrical generator.
• After it passes through the turbine, the steam is
condensed in a condenser and recycled to where it was
heated; this is known as a Rankine cycle.
• The greatest variation in the design of thermal power
stations is due to the different fuel sources.
• In India 65% of total power is generated by the Thermal
Power Stations.
THERMAL PLANT

Thermal ENERGY …
• Almost all coal, nuclear, geothermal, solar thermal
electric, and waste incineration plants, as well as many
natural gas power plants are thermal.
• Steam power plants may be either condensing or non‐
condensing type.
• According to use, plants can be classified into:‐
– Industrial power plants or captive power plant.
– Central power plants or common plants.

Thermal ENERGY …
EFFICIENCY OF STEAM POWER PLANTS
• Thermal efficiency of plant is defined as the ratio of the
heat equivalent of mechanical energy transmitted to
the turbine and heat of combustion (about 30%).
• Over all efficiency is the ratio of heat equivalent of
electrical output to the heat of combustion (29%).
Losses in steam plant
• a) Boiler house losses
– i) dry flue gases 5%
– ii) moisture in gases 5%
– iii) ash and unburnt carbon 1%
– iv) radiation and leakage 2.5%
– v) unknown losses 2.5%
TOTAL 16%KN. Chandra Bose, Asst. Professor, GECT

Thermal ENERGY …
• b) Turbine losses
– Heat rejected to condenser 54%
– Alternator losses 01%
– Thus out put is 29%
• Thermal efficiency mainly depends on 3 factors –
– Pressure
– Temperature of the steam entering the turbine
– Pressure in the condenser
• Thermal efficiency increase with increase in temp and
pressure of steam entering the turbine.

Thermal ENERGY …
• Which effectively increased by decreasing the pressure in the
condenser and usually kept very low at 0.04kg/cm2.
• It can also increased by re‐heating the steam.
Classification
• Classified by the type of fuel and the type of prime mover
installed.
– By fuel
• Fossil‐fuel power stations
• Nuclear power plants
• Geothermal power
• Biomass‐fuelled power plants
• In integrated steel mills, blast furnace exhaust gas is a low‐cost, fuel.
• Waste heat from industrial processes is occasionally concentrated enough
to use for power generation.
• Solar thermal.

Thermal ENERGY …
– By prime mover
• Steam turbine
• Gas turbine
• Combined cycle
• Internal combustion reciprocating engines
• Microturbines, Stirling engine

Thermal ENERGY …
• Factors to be considered
– Nearness to the load Centre
– Supply of water
– Availability of coal
– Land requirement
– Type of land
– Transportation facilities
– Labour supplies
– Ash disposal
– Distance from polluted area
Selection of site for steam power plants

Thermal ENERGY …
• 1. Load centre: ‐
– Plant should be as near as possible to the load centre so that the
transmission cost and losses are minimum.
• 2. Supply of water: ‐ Large amount of water is required
• to raise the steam in the boiler
• for cooling purpose
• As carrying medium for ash disposal
• Drinking purpose.
– In plants approximately 1.26x106 k cals of heat per MW
per Hour has to be disposed off in the condenser.
– In direct circulation from source of water, 120m3 of
water is required per MW per hour.

Thermal ENERGY …
– Efficiency of direct cooled plant is 0.5% higher than that of plant
cooled by cooling towers.
– Hence saving is Rs.7.5lacs per year in fuel cost for a 2000MW
station.
– Hence plant should be located near sea, river or lake.
• 3. availability of coal: ‐
– huge amount of coal is required for raising steam – 20,000
tonnes per day for a 2000MW station.
– Govt. policy is to use only low grade coal with 30 to 40% ash
content for power generation.
• 4. Land requirement:
– For coal storage, cottage, and ash disposal etc.
– For a 2000MW plant, around 200 to 250 acres land is required.
– Consider future expansion while selecting land.

Thermal ENERGY …
• 5. Type of land:
– Should be of good bearing capacity.
– Over all load may come around 7kg per cm2
– Reasonably plain land is suitable.
• 6. Transportation
• 7. Labour supplies: ‐ skilled and un‐skilled
• 8. Ash disposal:
– Main waste from plant is ash which may come around 3.5 tonnes
per day.
– It may be used for building purpose or brick making.

Thermal ENERGY …
WORKING OF STEAM PLANT
• A coal based thermal power plant converts the chemical
energy of the coal into electrical energy.
• Achieved by raising the steam in the boilers, expanding it
through the turbine and coupling the turbines to the
generators which converts mechanical energy into
electrical energy.
• Steam after expansion, condensed and fed into boiler
again.
• Coal based thermal power plant works on the principal
of Modified Rankine Cycle.

Thermal ENERGY …

Thermal ENERGY …
• A deaerator is a device used for the removal of oxygen and other
dissolved gases from the feedwater.
• Dissolved oxygen in boiler feed water will cause serious corrosion,
damages the steam systems by attaching to the walls of metal
piping and other metallic equipment and forming oxides (rust).
• Dissolved carbon dioxide combines with water to form carbonic acid
that causes further corrosion.
• Most deaerators are designed to remove oxygen down to levels of 7
ppb by weight (0.005 cm³/L) or less as well as essentially eliminating
carbon dioxide.
• Types of deaerators:‐ the tray‐type and the spray‐type:
• The tray‐type (also called the cascade‐type) includes a vertical
domed deaeration section mounted on top of a horizontal
cylindrical vessel which serves as the deaerated boiler feedwater
storage tank.
• The spray‐type consists only of a horizontal (or vertical) cylindrical
vessel which serves as both the deaeration section and the boiler
feedwater storage tank.

Thermal ENERGY …

Thermal ENERGY …
Components of Coal Fired Thermal Power Station:
Coal Preparation
• i)Fuel preparation system:
– The raw feed coal from the coal storage area is first crushed into
small pieces and then conveyed to the coal feed hoppers at the
boilers.
– The coal is next pulverized into a very fine powder, so that coal
will undergo complete combustion during combustion process.
• ii)Dryers:
– Used in order to remove the excess moisture from coal.
– presence of moisture will result in fall in efficiency due
to incomplete combustion and also result in
CO emission. KN. Chandra Bose, Asst. Professor, GECT

Thermal ENERGY …
• iii)Magnetic separators:
– coal may contain iron particles. These iron particles may result in
wear and tear.
– so they are removed with the help of magnetic separators.
– The coal finally transferred to the storage site.
– There are two types of storage:
– 1. Live Storage(boiler room storage):
• This storage consists of about 24 to 30 hrs. of coal
requirements of the plant.
• The live storage can be provided with bunkers & coal bins.
• Bunkers are enough capacity to store the requisite of coal.
From bunkers coal is transferred to the boiler grates.

Thermal ENERGY …
– 2. Dead storage‐
• stored for future use.
• Mainly it is for longer period of time
• It is also mandatory to keep a backup of fuel for specified
amount of days depending on the reputation of the company.
Forms of storages are :–
• Stacking the coal in heaps over available open ground areas.
• Under cover or alternatively in bunkers.
• Allocating special areas & surrounding these with high
reinforced concerted retaking walls.
• A Boiler or steam generator essentially is a container into which
water can be fed and steam can be taken out at desired pressure,
temperature and flow.
Boiler and auxiliaries

Thermal ENERGY …
• The boiler should have a facility to burn a fuel and release the heat.
The functions of a boiler:‐
– 1. To convert chemical energy of the fuel into heat energy.
– 2. To transfer this heat energy to water for evaporation as well to
steam for superheating.
The basic components of Boiler are: ‐
• Furnace and Burners :‐ A furnace is a device used for heating.
• Steam and Superheating
• Bolilers are classified as:
1. Fire tube boilers :
– In fire tube boilers, hot gases are passed through the tubes and
water surrounds these tubes.
– Simple, compact and rugged in construction.
– Depending on whether the tubes are vertical or horizontal these
are further classified as vertical and horizontal tube boilers.

– In this since the water volume is more, circulation will be poor.
– So they can't meet quickly the changes in steam demand.
– High pressures of steam are not possible,
– Maximum pressure that can be attained is about 17.5kg/cm2.
– Due to large quantity of water in the drain it requires more time
for steam raising.
2. Water tube boilers :
– Here Water is inside the tubes and hot gases are outside the
tubes.
– Hot gases which surrounds these tubes will convert the water in
tubes in to steam.
– Attain pressure as high as 125 kg/sq cm and temperatures from
315 to 575 centigrade.

• Superheater :
– A device which removes the last traces of moisture from the
saturated steam leaving the boiler tubes and also heated
above its saturation temperature.
– The superheater may consist of one or more stages of tube
banks arranged to effectively transfer heat from the
products of combustion.
– Carbon steel – upto 950oF, stainless steel – 1200oF
– Superheaters are classified as convection , radiant or
combination of these.
Reheater :
– Reheater is also steam boiler component in which heat is
added to the intermediate‐pressure steam.
– The steam after reheating is used to rotate the second
steam turbine

Condenser :
– Steam after passing through turbine comes to condenser.
– Condenser refers to the shell and tube heat exchanger installed
at the outlet of every steam turbine.
– These are heat exchangers which convert steam from its gaseous
to its liquid state.
– Condensers are classified as (i) Jet condensers or contact
condensers (ii) Surface condensers.
Cooling Towers :
– The condensate (water) formed in the condenser after
condensation is initially at high temperature.
– It is a tower‐ or building‐like device in which atmospheric air
circulates in direct or indirect contact with warmer water.

Economiser :
– Flue gases coming out of the boiler carry lot of heat.
– Function of economiser is to recover some of the heat from the
heat carried away in the flue gases up the chimney and utilize for
heating the feed water to the boiler.
– Placed in the passage of flue gases in between the exit from the
boiler and the entry to the chimney.
– The use of economiser results in saving in coal consumption ,
increase in steaming rate and high boiler efficiency by 10 – 12%.
Prime Movers:
– Converts steam energy into mechanical energy.
– Reciprocating type or turbines, (common is turbines).
– Turbines gives high speed.

Steam turbines:
– There is no pistons, slide valves and no fly wheels.
– Classified into impulse and reaction type Turbine.
• In an Impulse turbine, steam expands in stationary nozzles and
there is no pressure drop over the blades or runner.
• Has high speed and ample clearance between runner and
stationary blades.
• In a reaction turbine, the steam does not expands in nozzle but
expands as flows over the blades.
• They are of low speed.
Control room:
– Houses all necessary measuring instruments for each
panel.
– Separate battery room and a motor generator set or a
rectifier is installed for control circuit.

Advantages:
• The fuel used is quite cheap.
• Less initial cost as compared to other generating plants.
• It can be installed at any place irrespective of the existence of coal.
• It require less space as compared to Hydro power plants.
• Cost of generation is less than that of diesel power plants.
• Suitable for rapidly changing loads and can operate under 25% over load
continuously.
Disadvantages:
• It pollutes the atmosphere due to production of large amount of
smoke and fumes.
• It is costlier in running cost as compared to Hydro electric plants.
• Requires huge amount of water.
Merits and Demerits of Steam Plant

 Diesel oil is used as fuel.
 Diesel plants are uneconomical owing to oil cost.
 Commonly installed, where other sources of fuel is not
available.
Selection of site:
 Distance from load centre
 Availability of land
 Availability of fuel
 Transportation facility
 Availability of water
 Distance from populated area
 Types of land
Diesel Electric Power Plant

 Diesel Engine
 Air filter and Supercharger :
 Exhaust system :
 Fuel System :
 Cooling System :
 Starting System :
 Governing System :
 Diesel Engine Generator :
Elements of Plant

Diesel Engine :
 which develops power.
 They may be 4 strokes or 2 stroke engine.
 4 stroke engines has lower fuel consumption, more flexibility, better
scavenging and higher efficiency than 2 stroke.
 Cylinders are arranged in V shape to make the engine more
compact.
 6 to 8 cylinders are commonly used.
 Speed is in the range of 500‐1000 rpm.
 The diesel engines are compression ignition type.
 Diesel engines are available in sizes from 75kW to 3750kW.

Air filter and Supercharger :
 The function of air filter is to remove the dust from the air.
 The function of supercharger is to increase the pressure of air
supplied to the engine to increase the power of the engine.
 The supercharger is driven by the engine.
Exhaust system :
 This includes silencer and connecting ducts.
 silencer is required in between the engine and the intake system.
 The temperature of exhaust gases are really high.
 Which can be used for heating the oil or air supplied to the engine.

Fuel System :
 This includes fuel storage tank, fuel pump, fuel transfer pump,
strainers and heaters.
 The fuel is supplied according to the load on the plant.
 Strainers are provided to remove the suspended impurities.
 Heaters are required to heat the oil, especially during winter
seasons.
Cooling System :
 Includes oil pumps, oil tanks, filters, coolers and connecting pipes.
 The function of the lubricating system is to reduce the friction of
moving parts and to reduce the wear and tear of the engine parts.
 The life of engine and its efficiency largely depends on the
lubricating system.

Starting System :
 Includes compressed air tanks.
 Function is to start the engine from cold by supplying the compressed air.
Governing System :
 Their function is to maintain the speed of the engine constant irrespective
of load on the plant.
 Done by varying fuel supply to the engine according to load.
Diesel Engine Generator :
 The generators is of rotating field, salient pole construction, speed
ranging from 214 to 1000 rpm.
 Capacities ranging from 25‐5000 kVA at 0.8 power factor lagging.
 Generators are coupled directly to diesel engine.
 Provided with voltage regulators to allow voltage regulation.
 Excitation is usually at 115 to 230 V from a DC exciter, usually coupled to
the engine shaft through a belt.

• The only purpose of a nuclear power plant is to produce
electricity.
• Power plant needs a source of heat to boil the water which
becomes steam and turbine turns an electrical generator.
• In a nuclear plant the source of heat is a nuclear reactor.
• Fuel for a nuclear reactor is uranium, but not just any
uranium.
• Most uranium atoms (99.3%) consist of a nucleus with 146
uncharged neutrons and 92 positively charged protons.
• Adding the number of neutrons and protons, these atoms
have a total of 238 neutrons and protons.
NUCLEAR POWER PLANT

HOW IT WORKS??
 However, not all uranium atoms have 146 neutrons;
0.7% have 143, so this is called U‐235.
 The most important difference is that U‐235
spontaneously splits, producing two smaller nuclei
plus 2 to 5 neutrons.

• To have U‐235 fission efficiently, the uranium fuel is enriched.
• Uranium has gone through a process to increase the content of U‐
235 from 0.7% to 3 to 4%.
PROCESS:
– Energy is released from uranium.
– Uranium atom is split into two.
– Energy released in the form
of radiation and heat.
– Uranium is first formed into
pellets and then into long rods.
– The uranium rods are kept cool
by submerging them in water.
– While they are remove from the
water, nuclear reaction takes place causing heat.
Nuclear Power Plant

 The amount of heat required is controlled by raising and lowering
the rods.
 If more heat is required the rods are raised further out of the water
and if less is needed they lower further into it.
 The most common nuclear fuels are 235U and 239Pu.
Nuclear Power Plant

Nuclear Power Plant
• • U235 + n → ﬁssion + 2 or 3 n + 200 MeV
 If each neutron releases two or more neutrons, then the
number of fissions doubles in each generation.
 In that case, in 10th generations there are 1,024 fissions
and in 80 generations about 6 x 10 23 (a mole) fissions.

 PLANT LAYOUT
Nuclear Power Plant

TYPES OF NUCLEAR RECATOR
BOILING WATER
REACTOR
PRESSURIZED WATER
REACTOR

PRESSURIZED WATER REACTOR

BOILING WATER REACTOR

Nuclear Power Plant
NUCLEAR REACTOR
 A nuclear reactor is a device in which nuclear chain reactions are
initiated, controlled, and sustained at a steady rate.
CONTROL RODS
 Control rods absorbs neutron's.
 The control rods essentially contain neutron absorbers like,
boron, cadmium or indium.
STEAM GENERATORS
 Convert water into steam from heat produced in reactor core.
Either ordinary water or heavy water is used as the coolant.

STEAM TURBINE
 Extracts thermal energy from pressurized steam, and converts it
into useful mechanical power.
 Various high‐performance alloys and super alloys have been used
for steam generator turbine.
COOLANT PUMP
 The coolant pump pressurizes the coolant to155bar.
 The pressure of the coolant loop is maintained almost constant.
Nuclear Power Plant

FEED PUMP
 Steam coming out of the turbine, flows through the condenser for
condensation and recirculate for the next cycle of operation.
 The feed pump circulates the condensed water in the working fluid loop.
CONDENSER
 Used to condense vapour into liquid.
 The objective of the condenser are to reduce the turbine exhaust
pressure.
 Which increases the efficiency and to recover high quality feed water in
the form of condensate & feed back it to the steam generator without
any further treatment.
Nuclear Power Plant

COOLING TOWER
 Transfer process waste heat to the atmosphere.
 Water circulating through condenser is taken to the cooling tower
for cooling and reuse.
Nuclear Power Plant

ADVANTAGES
 Fission is the most energy efficient process.
 Nuclear power generation does emit relatively low amounts of
carbon dioxide (CO2).
 The emissions of green house gases (global warming) relatively
little.
 It is possible to generate a high amount of electrical energy.
Nuclear Power Plant

DISADVANTAGES
 The problem of radioactive waste is still an unsolved one.
 High risks: It is technically impossible to build a plant with 100%
security.
 Uranium is a scarce resource, its supply is estimated to last only for
the next 30 to 60 years depending on the actual demand.
Nuclear Power Plant

DISADVANTAGES
 Nuclear power plants as well as nuclear waste could be preferred
targets for terrorist attacks.
 During operation radioactive waste is produced, which in turn can
be used for the production of nuclear weapons.
Nuclear Power Plant

Indian Nuclear Program: The
Constraints
• Uranium ore reserves only for 10,000MW for 40 years
• Slow growth of nuclear electric power: ~1000 MW
annually
• Major dependence on Pu and U233.
• Complex fuel technologies. Total capacity limited
Nuclear Power Plant

Nuclear Power: The Present Status
0
2000
4000
6000
8000
10000
12000
14000
1969 1973 1981 1984 1986 1991 1992 1993 1995 2000 2005 2006 2015
InstalledCapacity(MW)
Planned
Presently installed
Nuclear Power Plant

Indian Energy Scenarios: 2015
Coal
60.44%
Gas
14.49%
Diesel
0.48%
Nuclear
5.06%
Hydro
15.96%
Solar thermal
0.40%
Biomass
1.19%
Wind
1.99%
Gas
14.49%
Diesel
0.48%
Nuclear
14.60%
Hydro
15.96%
Solar thermal
0.40%
Biomass
1.19%
Wind
1.99%
Coal
50.90%
Same Fuel Mix as now Aggressive Nuclear Capacity Addition
• Reduction in annual coal consumption ~ 100 Million Tons
• Reduction in annual CO2 Emissions > 170 Million Tons
• ~ Total present CO2 emissions of Netherlands !
Nuclear Power Plant

Renewable energy
The Ultimate Renewable
Resources

 A renewable resource is a natural resource with the
ability to reproduce through biological or natural
processes and replenished with the passage of time.
 Renewable resources are part of our natural
environment and form our eco‐system.
Energy generated by using
wind
Tides
Solar
geothermal heat
biomass including farm and animal waste as
well as human excreta.
Renewable energy

 All renewable energy, ultimately comes from the sun.
 The earth receives 1.74 x 1017 watts of power (per hour) from the
sun.
 About one or 2 percent of this energy is converted to wind energy.
WIND POWER Renewable energy

Working:
 The terms wind energy or wind power describe the
process by which the wind is used to generate mechanical
power or electricity.
 Wind turbines convert
the kinetic energy in the
wind into mechanical
power.
 Gross wind power
potential of India is
estimated to be about
20,000 MW, wind power
projects of 970 MW
capacities were installed
till March. 1998
Renewable energy

Consists of three crucial parts:
 Rotor blades –
 When the wind forces the blades to move, it has transferred some of its
energy to the rotor.
 Shaft –
 Shaft is connected to the center of the rotor.
 When the rotor spins, the rotor transfers its mechanical, rotational energy to
the shaft.
 High‐speed shaft: Drives the generator.
 Low‐speed shaft: The rotor turns the low‐speed shaft at about 30 to 60
rotations per minute.
 Generator
• Anemometer:
– Measures the wind speed and transmits wind speed data to the
controller.
• Brake:
– A disc brake, which can be applied mechanically, electrically, or
hydraulically to stop the rotor in emergencies.
Parts of Wind Turbines
Renewable energy

• Controller:
– The controller starts up the machine at wind speeds of about 8
to 16 miles per hour (mph) and shuts off the machine at about
55 mph.
– Turbines do not operate at wind speeds above about 55 mph
because they might be damaged by the high winds.
• Gear box:
– Gears connect the low‐speed shaft to the high‐speed shaft and
increase the rotational speeds from about 30 to 60 rotations per
minute (rpm) to about 1000 to 1800 rpm.
• Nacelle:
– The nacelle sits at top of the tower and contains the gear box,
low‐ and high‐speed shafts, generator, controller, and brake.
Some nacelles are large enough for a helicopter to land on.
Renewable energy

Pitch:
– Blades are turned, or pitched, out of the wind to control the
rotor speed and keep the rotor from turning in winds that are
too high or too low to produce electricity.
Rotor:
– The blades and the hub together are called the rotor.
Tower:
– Towers are made from tubular steel, concrete, or steel lattice.
– Because wind speed increases with height, taller towers enable
turbines to capture more energy and generate more electricity.
Wind direction:
– This is an “upwind” turbine, so‐called because it operates facing
into the wind.
Renewable energy

Wind vane:
– Measures wind direction and communicates with the yaw drive
to orient the turbine properly with respect to the wind.
Yaw drive:
– Used to keep the rotor facing into the wind as the wind direction
changes
Yaw motor:
– Powers the yaw drive.
Renewable energy

Wind power
– The power in the wind is proportional to:
• the area of windmill being swept by the wind
• the cube of the wind speed
• the air density – which varies with altitude
– The formula:
Power =½(density of air x swept area x velocity cubed)
P = ½.ρ.A.V3
where, P is power in watts (W)
ρ is the air density in (kg/m3)
A is the swept rotor area in (m2)
V is the wind speed in (m/s)
Renewable energy

 Mean wind speed is from, 6 to 10 m/s.
Renewable energy

 It is a renewable source of energy.
 Wind power systems are non‐polluting.
 Wind energy systems avoid fuel provision and transport.
 On a small scale up to a few kilowatt, system is small.
 Wind energy available is fluctuating in nature.
 Wind energy needs storage capacity because of its
irregularities.
 Wind energy systems are noisy in operation.
 Wind power systems have a relatively high overall weight.
ADVANTAGES OF WIND ENERGY
DISADVANTAGES OF WIND ENERGY
Renewable energy

What is Tidal Energy?
– Tidal energy is the utilization of the variations in sea level caused
primarily by the gravitational effects of the moon, combined
with the rotation of the Earth.
• Tides generated by the combination of the moon and sun’s
gravitational forces
• Greatest affect in spring when moon and sun combine forces
• Bays and inlets amplify the height of the tide
• For energy production, the height difference needs to be at least 5
meters.
 India possesses 8000‐9000 MW of tidal energy potential.
Tidal Energy
Renewable energy

• Tidal Energy
Renewable energy

• Two types of tidal plant facilities.
– Tidal barrages
– Tidal current turbines
• Ideal sites are located at narrow channels and
experience high variation in high and low tides.
Renewable energy

Tidal Barrage •Two types:
• Single basin system-
Ebb generation: During flood tide
basin is filled and sluice gates are
closed , trapping water. Gates are
kept closed until the tide has ebbed
sufficiently and thus turbines start
spinning and generating electricity.
Flood generation: The basin is filled
through the turbine which generate
at flood tide.
Two way generation: Sluice gates and
turbines are closed until near the end
of the flood tide when water is
allowed to flow through the turbines
into the basin creating electricity. At
the point where the hydrostatic head
is insufficient for power generation
the sluice gates are opened and kept
open until high tide when they are
closed. When the tide outside the
barrage has dropped sufficiently
water is allowed to flow out of the
basin through the turbines again
creating electricity.
Double-basin system: There are two
basins, but it operates similar to en
ebb generation, single-basin system.
The only difference is a proportion of
the electricity is used to pump water
into the second basin allowing
storage.
• Utilize potential energy
• Tidal barrages are typically dams built
across an estuary or bay.
• consist of turbines, sluice gates,
embankments, and ship locks.
Basin

Tidal current turbines
• Extracts kinetic energy from
moving water generated by tides.
• Operate during flood and ebb
tides.
• Consists of a rotor, gearbox, and
a generator. These three parts are
mounted onto a support
structure. There are three main
types:
▫ Gravity structure
▫ Piled structure
▫ Floating structure

-Advantages and Disadvantages-
• Advantages
– The energy is free – no fuel needed, no waste
produced
– Not expensive to operate and maintain
– Can produce a great deal of energy
• Disadvantages
– Depends on the waves – sometimes you’ll get
loads of energy, sometimes almost nothing
– Needs a suitable site, where waves are
consistently strong
– Some designs are noisy. But then again, so are
waves, so any noise is unlikely to be a problem
– Must be able to withstand

-Environmental Impact-
– Noise pollution
– Displace productive fishing sites
– Change the pattern of beach sand
nourishment
– Alter food chains and disrupt migration
patterns
– Offshore devices will displace bottom-
dwelling organisms.

What is Solar Energy?
 Originates with the
thermonuclear fusion
reactions occurring in
the sun.
 Represents the entire
electromagnetic radiation
(visible light, infrared,
ultraviolet, x‐rays, and
radio waves).
Renewable energy
Solar Energy

How much solar energy?
 The surface receives about 47% of the total solar energy.
 Sun radiates energy of 3.5x1023kW into space and only
2x1014kW reaches the earth.
 Photovoltaic cells are capable of directly converting
sunlight into electricity.
 A simple silicon
Wafer converts
light energy into
Voltage.
 Produced based
on types of silicon
(n‐ and p‐types)
used for the layers.
Each cell=0.5 volts.
Renewable energy

• Battery needed as storage.
• No moving partsdo not wear out.
• Because they are exposed to the weather, their lifespan is
about 20 years.
 India gets more than 5,000 trillion kWh of Solar Energy
every year.
 Solar Energy is successfully used in residential and
industrial settings for cooking, heating, cooling, lighting,
space technology, and for communications among other
uses.
 Solar panels are one of the most important factors in the
generation of Solar Energy.
 On an average, 1 Sq. Ft. of Solar Panel generates 10.6 W
of power.
Renewable energy

 Efficiency of cells is up to 23%/ improving.
 Solar collectors are of mainly two types‐
 Flat plate collectors
 Focussing or concentrating collectors.
 Cylindrical parabolic concentrators
 Paraboloids, mirror arrays
Renewable energy


Renewable energy

Different Arrangements of Plant Renewable energy

Geo‐Thermal Energy:
• Geo‐thermal energy is the heat of the earth's interior. This
energy is manifested in the hot springs.
• India is not very rich in this source.
Energy from Biomass:
• Biomass refers to all plant material and animal excreta
when considered as an energy source.
• Some important kinds of biomass are inferior wood,
urban waste, farm animal and human waste.
Renewable energy


Renewable energy

Renewable energy

Advantages of Geothermal Energy
• Significant Cost Saving :
• Environmental Benefits :.
• Direct Use :
• Job Creation and Economic Benefits :
Disadvantages of Geothermal Energy
• Not Widespread Source of Energy :
• High Installation Costs :
 Can Run Out Of Steam
 Suited To Particular Region
 May Release Harmful Gases :
Renewable energy

 The field of MHD was initiated by Hannes Alfvén , for
which he received the Nobel Prize in Physics in 1970.
 Magneto hydrodynamics (MHD) (magneto fluid
dynamics or hydro magnetics) is the academic
discipline which studies the dynamics of electrically
conducting fluids.
 Examples of such fluids include plasmas, liquid metals,
and salt water.
Renewable energy
MAGNETO HYDRO DYNAMIC POWER
GENERATION (MHD )

 MHD power generation is a new system of electric power
generation which is said to be of high efficiency and low
pollution.
 In advanced countries MHD generators are widely used
but in developing countries like INDIA, it is still under
construction.
 An MHD generator is a device for converting heat energy
of a fuel directly into electrical energy without
conventional electric generator.
Renewable energy

• Conventional Gen: ‐ conductor moves across a magnetic
field, a voltage is induced in it.
• In MHD generator, the solid conductors are replaced by a
gaseous conductor, an ionized gas.
• If such a gas is passed at a high velocity through a
powerful magnetic field, a current is generated and can be
extracted by placing electrodes in suitable position in the
stream.
Renewable energy
PRINCIPLES OF MHD POWER
GENERATION

Renewable energy

• The flow direction is right angles to the magnetic fields
direction.
• An electromotive force (or electric voltage) is induced in
the direction at right angles to both flow and field
directions.
Renewable energy

 The conducting flow fluid is forced between the plates
with a kinetic energy and pressure differential sufficient to
over come the magnetic induction force Find.
 Ionization is produced either by thermal means.
 The atoms of seed element split off electrons.
 The presence of the negatively charged electrons makes
the gas an electrical conductor.
Renewable energy

 The conversion efficiency is around 50%.
 Still higher efficiencies are expected in future, around 60 –
65%.
• Large amount of power is generated.
• It has no moving parts, so more reliable.
• The closed cycle system produces power, free of pollution.
• It has ability to reach the full power level as soon as
started.
 It is possible to use MHD for peak power generations and
emergency service.
Renewable energy
ADVANTAGES

Economics of Power Generation
• The function of a power station is to deliver power
at the lowest possible cost per kilo watt hour.
(Practically not possible, explained by Economics of power Generation).
• The total cost is made up of fixed and operating
cost.
– Fixed cost consists:‐
• interest on the capital,
• taxes, insurance, depreciation
• salary of managerial staff
– operating expenses
• cost of fuels, water, oil, labor, repairs and maintenance
etc.Sunday, August 05, 2012 144KN. Chandra Bose, Asst. Professor, GECT

 The cost of power generation can be minimized by :
1. Selecting equipment of longer life and proper
capacities.
2. Running the station at high load factor.
3. Operation through fewer men.
4. Increasing the efficiency of plant.
5. Proper maintenance in time.
6. Keep efficient supervisors.
7. Using a plant of simple design that does not
need highly skilled personnel.

 Hence plant selection can be based on fixed and
operating cost.
 For nuclear plant fuel cost is relatively low and
fixed, operating, maintenance charges are high.
 For diesel, fuel cost is high
 For hydro, fixed charges are high (70 to 80%).
 Hence generation must be regulated according to
demand and plant should run at full load at which
they give max.η.

 Schedule the units to fit the load curve as
closely as possible.
 Demand is varying with time, hence
generation must meet the demand at any
time.
 In an electric power plant, the capital cost of
generating equipment's increase with an
increase in efficiency.

General terms in power station practice,
to run efficiently:
1. Load curve :
– Load curve is the plot of load in kilowatts versus time
usually for a day or a year.
2. Load duration curve :
– Is the plot of load in kilowatts versus time duration for
which it occurs.
3. Maximum demand :
– Is the greatest of all demands which have occurred during
a given period of time.
4. Average load :
– Is the average load on the power station in a given period
(day/month or year)

5. Base load :
– Is the minimum load over a given period of time.
6. Connected load :
– Is the sum of the continuous ratings of the load
consuming apparatus connected to the system.
7. Peak load :
– Is the maximum load consumed or produced by a unit
or group of units in a stated period of time.
– It may be the maximum instantaneous load or the
maximum average load over a designated interval of
time.

8. Demand factor :
– Is the ratio of maximum demand to the connected load
of a consumer.
9. Diversity factor :
– Is the ratio of sum of individual maximum demands to
the combined maximum demand on power stations

10. Load factor :
– Is the ratio of average load during a specified period to
the maximum load occurring during the period.
Load factor = Average Load / Maximum demand
11. Station load factor :
– Is the ratio of net power generated to the net maximum
demand on a power station.

12 . Plant factor :
– Is the ratio of the average load on the plant for the
period of time considered.
13. Capacity factor :
– Is the ratio of the average load on the machine for a
period of time considered, to the rating of the machine.
14. Demand factor :
– Is the ratio of maximum demand of system or part of
system, to the total connected load of the system.

15. Utilization factor :
– Is the ratio of maximum demand of a system or part of the
system, to the rated capacity of the system, or part of the
system, under consideration.
16. Firm power :
– Firm power is the power intended always to be available
even under emergency conditions.
17. Prime power :
– Prime power is the maximum potential power constantly
available for transformation into electrical power.
18. Cold reserve :
– Is the reserve generating capacity that is available for
service but not in operation.

19. Hot reserve :
– Is the reserve generating capacity that is in operation
but not in service.
20. Spinning reserve :
– Spinning reserve is the reserve generating capacity that
is connected to the bus and ready to take load.
21. Run of river station :
– Run of river station is a hydro‐electric station that
utilizes the stream flow without water storage.

– Split into two parts: fixed costs and variable costs.
(A) Fixed Cost :
– Fixed costs are to be borne by the plants irrespective of
the load.
These costs consist:‐
(i) Interest on capital :
– Capital includes the cost of land, buildings, equipment
installation, designing, engineering etc.
– Since the capital cost is fixed therefore interest on the
amount is considered as fixed cost.
(ii) Taxes :
– A power generating and distributing company has to pay
taxes to the Government.
– This amount is more or less fixed.
Cost of generation :

(iii) Cost of Transmission and Distribution :
– Involves huge capital expenditure.
– This involves cost of transmission lines, transformers,
substations and associated equipment. Interest on the
capital involved is considered as a fixed cost.
(iv) Depreciation:
– It is, decrease in value, caused by the wear due to
constant use of an equipment.

(v) Insurance :
– The plant and also life of some of workers working in
dangerous areas, has to be insured against various risks
involved.
– For this purpose a fixed sum is payable as premium for
the insurance cover.
vi) Salary for Managerial Staff :
– Irrespective of whether the plant works or not certain
managerial staff has to be retained by the organization.

(B ) Variable Cost :
– These costs vary in some proportion of the power
generated in a plant. Consist of:‐
(i) Cost of fuel :
– Cost of fuel is directly related with the amount of
power generated.
– For generating more power, more fuel is required.
– Cost of fuel may be 10% to 25% of the total cost of
production.
– In case of hydroelectric plants the cost of fuel is zero.

(ii) Maintenance and Repair Charges:
– To keep the plant in running condition, certain repairs
are always needed.
– Stock of some consumable and non‐ consumable items
has got to be maintained. All chargers for such staff are
considered as operating costs.
(iii) Wages:
– Salaries including allowances bonus, benefits etc. for
the workers.

A tariff is the rate of charge per kilowatt hour of
energy supplied to a consumer.
Requirements of a Tariff:
 It should be easier to understand
 Provides low rate for higher consumption
 Encourage the consumers having high load factor.
 It should take into account max. demand charges & energy
charges.
Tariff:

 Flat demand rate
 Straight line meter rate
 Step meter rate
 Block rate tariff
 Two part tariff
 Three part tariff
 Various type of tariffs can be derived from general equation
Y = DX+EZ+C
 Y = total amount of bill for the period considered
 D = Rate per kW of max demand
 X = max demand in kW
 E = energy rate per kW
 Z = Energy consumed in kWh during the given period
 C = Constant amount to be charged from consumer during each bill.
Types of Tariff:

1. Uniform Rate Tariff :
– A fixed rate per unit amount of energy consumed.
– This type of tariff accounts for all the costs involved in
the generation of power.
– Simplest tariff easily understood by consumers.
2. Two Part Tariff :
• The total charges are split into two parts –
– fixed charges based on maximum demand (in kW) plus
the charges based on energy consumption (in kWh).
– Additional provision is to be incorporated for the
measurement of maximum demand.
– Under such tariff, the consumers having 'peaked'
demand for short duration, are discouraged.
Types of Tariff cntd …

3. Block Rate Tariff :
– The fixed charges are merged into the unit charges for one
or two blocks of consumption.
– all units in excess being charged at low or high unit rate.
– Lower rates for higher blocks are fixed in order to
encourage the consumers for more and more
consumptions.
– This is done in case the plant has got larger spare capacity.
– Wherever the plant capacity is inadequate, higher blocks
are charged at higher rate in order to discourage the
consumers .
4. Three Part Tariff :
– An extension of the two part tariff.
– In this even if the consumer has got zero power
consumption, he has to pay some charges merely because a
connection has been provided to him.

5. Power Factor Tariff :
– In case the power factor of a consumer installation is low,
the energy consumption in terms of kW will be low.
– In order to discharge such consumers, power factor tariff is
introduced,
• which are of two types:‐
(a) Maximum kVA demand Tariff :
• In this instead of kW. the kVA consumption is measured and the
charge are Based partly or fully on this demand.
(b) Sliding Scale :
• In this case the average power factor is fixed say at 0.8 lagging.
• Now if the power factor of a consumer falls below by 0.01 or
multiples there of, some additional charges are imposed.
• A discount may be allowed in case the power factor is above 0.8.

 DEPRECIATION:
It is the deterioration of equipment's and decrease in
its value due to corrosion, weathering, and wear and
tear with use.
 Improvements in design and construction, obsolesce
factor rates the plants.
 Availability of better models with lesser over all cost in
generation, forces the old model to replace.
 Hence over all life span reduces, from what would be
normally expected.

 Methods used to calculate depreciation cost:
 Straight line method
 it is assumed that the property losses its value by the same
amount every year.

 A fixed amount of the original cost is deducted every year, so
that at the end of the utility period, only the scrap value is
left.
** Annual Depreciation, D = (original cost of the asset – Scrap
Value)/life in years
 Percentage method
 the property will lose its value by a constant percentage at
the beginning of every year.
** Annual Depreciation, D = 1‐(scrap value/original value)1/life in
year

 Sinking fund method
 the depreciation of a property is assumed to be equal to the annual
sinking fund plus the interest on the fund for that year.
 Unit method
 the property is studied in detail and loss in value due to life, wear
and tear, decay, obsolescence etc, worked out.
 Not calculating any fixed percentage of the cost of the property.
 Only experimental value can work out the amount of depreciation.

 The advantages of improved power factor:‐
 (i) reduction in load current
 (ii) increase in voltage level across the load,
 (iii) reduction in energy loss in the system (generators,
transformers, transmission lines and distributors) due to
reduction in load current.
 (iv) reduction in KVA loading of the generators and the
transformers which may relieve an over loaded system
or release capacity for additional growth of load
 (v) reduction in KVA demand charge for large
consumers.
ECONOMICS OF PF IMPROVEMENT

 ECONOMICS OF PF IMPROVEMENT
 Reduce expenditure on the power factor correcting
equipment.
 Result in reduction of maximum demand.
 thus affect an annual saving over the maximum
demand charge.
 the economical limit of power factor correction is
governed by the relative costs of the supply and power
factor correcting equipment.

 What is Power Factor ‐ and Why is it Important to My
Bottom Line:
 Electrical power is comprised of three components:
 real power (P),
 reactive power (Q)
 apparent power (S).
 Power factor is a measure of how
effectively electrical power is
being used.

 Reactive power, does not do any work but is
nonetheless needed to operate equipment.
 when a utility serves a facility that has poor power
factor, the utility must be capable of supplying higher
current levels to serve a given load.
 When a customer's power factor drops below the
minimum value, the utility collects a low power factor
revenue premium on their bill. Typically the lower the
power factor, the higher the premium.
 The most economical way to improve power factor is
by adding capacitors.

 capacitors serve as a leading reactive current
generator to counter the lagging reactive current in a
system.
 Maintaining a high power factor in a facility will yield
direct savings.
 As power factor of the system is improved, the total
current flow will be reduced ‐ which permits
additional loads to be added and served by the
existing system.
 Distribution losses can be reduced by the addition of
capacitors.
 Capacitors will also raise a circuit's voltage.

 capacitors act as a kVAR generator.
 the most efficient place to install them is usually
directly at an inductive load.
 Improvement of pf of 1 motor improves the plant's
overall reactive requirement.

THANKS

Electrical Power Generation, Transmission and Distribution Explained

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