00:00:00
[Laughter]
00:00:03
[Music]
00:00:47
so in the last few classes we are
00:00:50
talking about thermal power
00:00:52
plants and as you know the
00:00:57
load is a load means
00:01:00
we are consuming all the time consuming
00:01:02
electricity all the time and that
00:01:05
electricity consumption is continuously
00:01:07
varying why because when the Institute
00:01:11
starts say about
00:01:14
8:30 all the lights will be switched on
00:01:18
the industry start at around say 9:30
00:01:20
10:00 all the machines will be switched
00:01:22
on again at about 5:00 the machines will
00:01:25
be switched off so naturally the load
00:01:28
that the power stations have to carry
00:01:30
will be weing load okay again in the
00:01:33
evening all the lights will be on in the
00:01:36
summer all the fans are on in the winter
00:01:39
fans are not on so you have a varying
00:01:41
load in general if you plot it the
00:01:45
variation of the load against time it's
00:01:48
called the load
00:01:49
curve uh say we start
00:01:53
from uh midnight
00:02:02
and 1 2 3 4 5 6 7 8 9 10 11 12 again the
00:02:14
same thing continues right you have to
00:02:16
plot 24 hours
00:02:18
so 1 2 3 4 all that so at midnight you
00:02:25
would obviously expect very low load so
00:02:28
you can start from a very low
00:02:30
load period and then it will it will be
00:02:34
expected to increase around this time
00:02:38
right so around say 8:00 9:00 the lights
00:02:44
will be on the offices will will will be
00:02:47
turned on so you can expect something
00:02:49
like this right and then it goes
00:02:54
down uh it may not be exactly like this
00:02:57
though because that varies from season
00:02:59
seon to season that varies from City to
00:03:01
city city or rural area it depends on
00:03:04
that but what I am trying to point out
00:03:06
is that the load is continuously
00:03:09
varying and there is a particular
00:03:12
time normally that comes in the evening
00:03:15
like say 7:00 to 9:00 Prime Time when
00:03:19
the load is the highest there is a peak
00:03:21
power Peak load necessary so the whole
00:03:25
power generation has to satisfy this
00:03:27
varying power load how do you do that
00:03:31
now as you have understood the structure
00:03:34
of the power
00:03:35
plant there a
00:03:38
huge uh boiler is there that is
00:03:40
producing the Steam and that steam is
00:03:43
going into the turbine and the turbine
00:03:45
is rotating thereby producing the
00:03:49
power in order to change the amount of
00:03:52
power produced yes you can increase or
00:03:56
decrease the amount of steam that goes
00:03:59
into the turbine
00:04:00
okay you can do that that's a short-term
00:04:03
thing but after all the steam is coming
00:04:06
from the boiler and in order to change
00:04:09
the the steam production of the boiler
00:04:12
the coal production has to be coal input
00:04:15
has to be changed obviously you can feel
00:04:18
that in such a huge thing that whole
00:04:20
thing will be very slow Affair you
00:04:22
cannot really change the steam output
00:04:25
very
00:04:26
fast moreover such a such a big plant
00:04:29
can cannot be started very fast because
00:04:32
suppose such a five story building that
00:04:34
is a boiler it has to be heated up to
00:04:37
the temperature and then only the coal
00:04:40
starts firing and only when the
00:04:43
temperature reaches a certain level you
00:04:45
you get the steam output so the and
00:04:47
steam also has to reach that particular
00:04:49
pressure so that process takes
00:04:52
hours in very big power plants even
00:04:55
days maybe of the order of a day
00:05:00
so this
00:05:02
variation it is rather difficult for big
00:05:05
power plants to
00:05:07
take
00:05:08
okay big power plants normally can work
00:05:11
more or less at the same power level and
00:05:15
small variations are allowed all right
00:05:17
but not much relatively smaller power
00:05:21
plants can vary relatively faster
00:05:23
obviously because of the size is smaller
00:05:25
but nevertheless there is a limitation
00:05:27
to it so meeting the peak load meeting
00:05:31
the whole varying load demand is
00:05:34
normally a
00:05:35
problem how to meet that
00:05:38
problem you can meet that problem only
00:05:41
with that kind of a resource which can
00:05:44
be varied very
00:05:46
fast and one of the resources that can
00:05:48
be very very very fast is hydroelectric
00:05:51
power that is why in those states which
00:05:55
have a even uh balance between Coal
00:06:00
Fired thermal power plants and
00:06:01
hydroelectric power plants they are very
00:06:03
well off they can easily meet their
00:06:06
demands while the states that depend
00:06:10
more or less completely on thermal power
00:06:13
plant there they have a reasonable
00:06:16
amount of difficulty in meeting the peak
00:06:18
load right so normally you would say
00:06:21
that here is the the amount of
00:06:24
load this amount of load here is a
00:06:28
load that means power power demand this
00:06:31
is the base
00:06:33
right so this is called the base
00:06:38
load about this is called the
00:06:40
intermediate load and about this is
00:06:42
called the peak load and Peak load comes
00:06:46
for a period of say 2 to three hours per
00:06:48
day intermediate load comes more and
00:06:52
base load is always on so that is the
00:06:55
basic
00:06:56
idea in general the the large thermal
00:07:01
power plants CER to the base
00:07:04
load the medium size thermal power
00:07:08
plants get to the uh intermediate load
00:07:11
and pig load is a problem which I'll
00:07:13
come to a little later but where you
00:07:16
have the availability of hydroelectric
00:07:19
power there you can use that for the
00:07:22
peak loading
00:07:24
purpose also if you have hydroelectric
00:07:28
power hydroelectric power after all
00:07:30
comes from the rain and the rain is
00:07:33
varying all the time so if you have a
00:07:37
rain season you have huge amount of
00:07:39
water available and then that can be the
00:07:43
same water can be used to CER to the
00:07:45
base load because it's there anyway we
00:07:47
have
00:07:48
it so that the majority of the power
00:07:53
production can be shifted to
00:07:54
hydroelectric in those periods and
00:07:57
during the lean periods you may use it
00:07:59
only for the peing purpose okay so you
00:08:02
can easily see that a good balance
00:08:04
between the hydroelectric power
00:08:06
availability and the thermal power
00:08:09
availability makes a power
00:08:12
system rather sound
00:08:15
okay now Hydro power is not available
00:08:19
everywhere for example near kakur you
00:08:23
you have more or less seen the place our
00:08:25
place and the places around it have gone
00:08:28
on bicycle around
00:08:30
yes
00:08:31
obviously uh you have notice that there
00:08:33
is no place where you can really
00:08:35
generate hydr
00:08:36
power nearby okay because the land is
00:08:41
rather flat in order to generate Hydro
00:08:44
power you need elevated water which is
00:08:46
allowed to come down losing its
00:08:49
potential energy and thereby you can
00:08:50
generate so in Flat Lands it's rather
00:08:53
difficult unless you have got a
00:08:54
reasonably sized river that has already
00:08:57
a flow and that flow can be utilized
00:08:59
we'll come to those CL things
00:09:01
later the point that I'm trying to drive
00:09:03
home is that hydrac power is not
00:09:06
available
00:09:08
everywhere core fire power plants are
00:09:11
not also not uh economical
00:09:14
everywhere why because coal is available
00:09:16
in certain
00:09:18
spots and if you have to carry that coal
00:09:21
across the country to another place it
00:09:23
becomes rather
00:09:25
uneconomical so for the whole country it
00:09:28
is advantages to have the coal fire
00:09:32
power plants where there is availability
00:09:34
of number one the coal number two water
00:09:36
also it is water a lot of lot of it in
00:09:39
the for the cooling
00:09:41
purpose and the hydroelectric plants
00:09:44
where the availability is there and
00:09:47
naturally the whole system has to be
00:09:49
interconnected so that the places where
00:09:53
Excess hydr power is produced they can
00:09:56
transport that power to the places where
00:09:58
it is required
00:10:00
and where the cool fired power plants
00:10:02
are there they can transport the the
00:10:04
that power to the place where they are
00:10:06
required that is why the whole
00:10:09
country's uh electric power network is
00:10:12
interconnected it is called the power
00:10:15
grid okay the whole country's uh power
00:10:19
system is interconnected all the loads
00:10:21
are there all the machines all the the
00:10:25
generators are all
00:10:27
interconnected except for those those
00:10:30
isolated cases like the an on where
00:10:33
obviously you cannot have a connected
00:10:34
power there has to be a it is an island
00:10:37
therefore the power grid is also
00:10:40
islanded so my point is that in order to
00:10:44
run the the whole system properly you
00:10:46
need to have hydroelectric power so the
00:10:49
next topic that we'll discuss is
00:10:51
hydroelectric
00:10:56
power now in hydroelectric power what
00:10:59
what are you actually doing you are
00:11:00
actually
00:11:01
using the energy that is available in
00:11:05
stored
00:11:07
water in the form of it's potential
00:11:11
energy
00:11:12
okay either you can use that potential
00:11:15
energy
00:11:17
directly
00:11:18
in converting that potential energy
00:11:21
directly into the kinetic energy of the
00:11:23
rotating Shaft or you can first convert
00:11:27
it into kinetic energy of the Rushing
00:11:28
Water
00:11:29
through a nozzle allow it to impinge on
00:11:32
something make it rotate there right so
00:11:35
you have the options of either using the
00:11:38
potential energy
00:11:39
directly or converting first into
00:11:42
kinetic energy of the water and then
00:11:45
utilizing it directly and you can also
00:11:47
have a mixture of the
00:11:49
two and
00:11:52
these categorize the different types of
00:11:55
turbines that are
00:11:56
used but essentially you need number one
00:12:00
a flow of
00:12:02
water a difference in level from where
00:12:06
it is Flowing to where it is
00:12:08
going okay that is called the head
00:12:12
remember it's not this head the head is
00:12:15
the the difference between the two
00:12:17
levels from where it is coming and to
00:12:20
where it is going so you need to have a
00:12:23
level difference that's the head and you
00:12:26
need to have a certain amount of
00:12:30
water that is coming in and what is the
00:12:32
total quantity of energy available
00:12:36
MGH okay so energy
00:12:57
available now we are often more
00:13:01
concerned with
00:13:02
power rather than
00:13:05
energy so power is the rate
00:13:09
of
00:13:10
mass and the and the water's water is
00:13:15
generally measured in volume not in
00:13:18
kilogram right so we will need to write
00:13:21
it in the form of row G row is the
00:13:26
density of water G is the acceleration
00:13:28
due to gas gravity and the
00:13:31
Q which is the discharge flow rate and
00:13:37
H now how are they expressed
00:13:40
the um so this is p power is this power
00:13:47
is then the
00:13:57
hydroelectric in whats
00:14:01
normally we would write it in mega
00:14:02
though I'm writing only the basic
00:14:05
unit G
00:14:13
is there no row is the density of water
00:14:18
which
00:14:21
is you know
00:14:24
that is
00:14:33
all right and you have the Q is the
00:14:42
discharge it is mq per second
00:14:46
right and you have the H which is the
00:14:54
head so if these are known you can find
00:14:58
out the power
00:15:04
right now in
00:15:08
deciding on
00:15:10
a whether a particular site is suitable
00:15:14
for hydr power generation or
00:15:18
not and in order to decide whether
00:15:22
decide the the okay what will be the
00:15:25
design criteria I'll come to that later
00:15:27
but you need to plan certain
00:15:31
things you see a river a flow some kind
00:15:35
of a elevated place where you have some
00:15:37
amount of uh energy available it's not
00:15:41
difficult to see that in order to have
00:15:42
power generation you have to have water
00:15:45
and that water has to be all the time
00:15:47
available it is either a perennial kind
00:15:50
of River or the water is available only
00:15:54
during seasons and it has to be stored
00:15:57
and then only it can be made use of at
00:16:00
all times so obviously there are certain
00:16:03
things you can easily see that you need
00:16:04
to understand number one how much is the
00:16:07
water
00:16:09
available what is the the seasonal
00:16:14
variation of the water
00:16:17
availability depending on that how much
00:16:20
will be the storage
00:16:23
capacity depending on that how much will
00:16:25
be the capacity of water Carriage that
00:16:28
that means there has to be a tube
00:16:31
designed and its diameter will depend on
00:16:33
how much water you expect to flow which
00:16:35
will again depend on the capacity of the
00:16:38
terbine you need to decide
00:16:41
that the amount that will not be able to
00:16:43
flow here will have to be diverted
00:16:47
through something called a Spiel way
00:16:48
that means the during the rainy season
00:16:51
you cannot allow all the water to pass
00:16:53
through the turbine there will be excess
00:16:54
water which has to be Spilled Out so all
00:16:57
these amounts need to be designed
00:16:59
right so we'll now take up this this
00:17:01
particular problem if you suppose chance
00:17:05
upon a place which looks like a feasible
00:17:08
site how do you make these
00:17:11
decisions this is the essential
00:17:13
engineering
00:17:14
problem okay
00:17:17
so what we'll need to know
00:17:20
essentially are a few things one
00:17:36
the quantity of water
00:17:40
available two
00:18:03
the quantity of water that can be
00:18:06
economically
00:18:08
store a noris might claim that all the
00:18:11
water that is coming will store it no it
00:18:13
is not visible obviously the storage
00:18:15
will depend on the availability of a
00:18:18
particular type of site in general the
00:18:21
the geographical location has to be such
00:18:23
that in most sites it is it is
00:18:25
surrounded by some kind of a hilly
00:18:27
terrain so that you don't have to conr a
00:18:29
dam in one side you construct a dam so
00:18:31
that you enclose a certain amount of
00:18:32
water so all these geographical
00:18:35
consideration has to be taken into
00:18:36
account in order to decide
00:18:39
this then we need to understand the head
00:18:43
of
00:18:56
water which can be utilized
00:19:01
then we need to understand
00:19:18
the distance of the site from the low
00:19:20
Center because many of the hydroelectric
00:19:23
power SES are situated in a very far off
00:19:28
place
00:19:29
and in that case
00:19:31
the the transport of the power from that
00:19:34
place to the load Center is also
00:19:36
economical consideration so this needs
00:19:38
to be
00:19:39
understood and
00:19:49
then the physical ACC accessibility if
00:19:52
it is very inaccessible
00:19:54
place but a a very good site then it it
00:19:58
may not be considered a very good site
00:20:00
because people have to be there people
00:20:02
have to be transported there so the
00:20:05
availability of Transport is also
00:20:06
important consideration just imagine the
00:20:08
situation where you have a very good
00:20:10
hydroelectric power plant but people
00:20:11
have to be transported by helicopter
00:20:13
obviously that will not be a very good
00:20:16
consideration because of the expense in
00:20:18
that so accessibility of the site will
00:20:21
be another consideration then you have
00:20:25
to also consider the cage
00:20:45
imagine the situation where you have
00:20:47
created a
00:20:48
dam but the rock underneath is very
00:20:52
pervious so that water does SIP through
00:20:55
which means that the the amount of water
00:20:57
that is stored will not be there it will
00:20:58
sip through go away so such this is
00:21:01
geographical geological consideration
00:21:04
this
00:21:12
see this has to be also consider so
00:21:15
these are the issues one needs to take
00:21:18
into account while U at least making the
00:21:21
initial plan whether a particular site
00:21:24
is feasible for that purpose or not
00:21:29
also there is another
00:21:31
Factor the
00:21:33
region where you are planning to to have
00:21:37
that hydric power plant that is after
00:21:40
all using the water that has been
00:21:43
received over a certain catchment
00:21:46
area Okay so for every hydroelectric
00:21:49
power plant or for every river there is
00:21:51
a catchment area in which the rain
00:21:55
coming in flows through and flows into
00:21:58
to that particular river which you
00:22:00
finally use for your hydric power
00:22:02
generation so you need to consider the
00:22:04
catchment area also the amount of
00:22:06
catchment area and what is the rain
00:22:09
characteristic rainfall characteristic
00:22:10
of that
00:22:12
area uh for
00:22:14
example
00:22:16
one uh cm of
00:22:21
rain how much water is
00:22:24
that you know that in every place the
00:22:26
meteorological Department says that so
00:22:28
much how much rainfall was there in what
00:22:29
unit is it expressed
00:22:31
ctim so how much water is that
00:22:35
physically huh yeah it has to be
00:22:37
multiplied by the area so how does it
00:22:40
translate this will be about 10^ 4
00:22:46
kg
00:22:52
per
00:22:54
okay so this amount of water will be
00:22:57
available if there is a 1 cm of
00:22:59
rain
00:23:01
and in that rain some amount of rain
00:23:05
will go away as uh
00:23:09
evaporation some amount of rain will
00:23:12
percolate through the soil into the
00:23:14
subsoil water
00:23:16
groundw only the amount the rest rest of
00:23:18
the amount will flow through the uh from
00:23:21
the various channels into that river
00:23:24
which will be available okay so you have
00:23:26
to consider these aspects how much of
00:23:28
this amount will actually be available
00:23:31
for power
00:23:35
generation okay
00:23:39
so at the at the beginning of the study
00:23:43
suppose you are sent to a particular
00:23:44
place where you are undertaking the
00:23:47
study whether a particular site is
00:23:48
feasible or
00:23:50
not there are a a a few stages of that
00:23:55
study number one
00:23:58
the
00:24:02
stages you see a hydr plan means a huge
00:24:06
expenditure and one does not really make
00:24:09
that expenditure unless you have a
00:24:12
properly planned
00:24:14
system and
00:24:16
plan is naturally done in stages first
00:24:20
you have to decide whether you really go
00:24:21
for a good planning or
00:24:23
not if planning means that also incur
00:24:25
expenditure you have to do many
00:24:27
measurements so the first stage is
00:24:30
called
00:24:41
the recognizance
00:24:44
study which is essentially a very
00:24:47
preliminary estimate of whether a site
00:24:51
is suitable or
00:24:52
not
00:24:55
okay that means in order to actually
00:24:58
undertake a feasibility study in general
00:25:01
the feasibility study of a particular
00:25:02
site is given to Consultants which
00:25:04
actually cost a lot so first one has to
00:25:07
decide whether a feasibility stud is
00:25:09
necessary at that stage at this stage
00:25:12
that is the absolutely preliminary stage
00:25:14
you go to a place and see that okay this
00:25:16
may be a good place this maybe will be
00:25:19
dependent on a few uh uh
00:25:23
numbers first you need to know the
00:25:27
average
00:25:34
annual
00:25:35
flow okay
00:25:59
the discharge available during the low
00:26:01
flow period that's more important
00:26:03
because you want a continuous power
00:26:05
output so the amount of dis that is
00:26:08
available when there's no
00:26:10
rain that is also an important
00:26:13
factor that you need to consideration
00:26:16
and then the
00:26:22
head so with this you can more or less
00:26:25
make an estimate whether the site
00:26:28
whether you should really go for the
00:26:31
site but this is definitely not
00:26:34
sufficient in order to make a plan for
00:26:37
the actual
00:26:38
installation so the next stage is
00:26:41
something more detailed that is called
00:26:43
the feasibility
00:26:44
study stage two
00:27:02
uh I'll I'll come to what exactly are
00:27:07
the things necessary in order to make
00:27:08
the feasibility study but at this
00:27:11
stage we essentially make the decision
00:27:33
should an investment commitment be
00:27:36
made because this is a a a big
00:27:39
investment in every hydroelectric power
00:27:41
plant it is basically the initial
00:27:43
investment that is
00:27:44
there in a coal F power plant there's a
00:27:47
continuous purchase of coal in hydrac
00:27:49
power plant there's none so the initial
00:27:52
investment is the main thing main
00:27:53
component so this decision has to be
00:27:55
made now this decision has to be
00:27:58
dependent in addition to the things that
00:28:02
we needed at the stage of the
00:28:04
recognation study will be the
00:28:06
variability
00:28:08
of the rainfall or the availability of
00:28:11
water during the
00:28:14
year uh how that is used I'll come to
00:28:17
that later how actually that that
00:28:19
information is used but in the
00:28:21
feasibility study stage you use that in
00:28:23
order to make an estimate of supposing
00:28:26
so much water is available
00:28:30
how big should be the the actual size of
00:28:34
the
00:28:35
turbine if it is small then the
00:28:38
investment is small but then a small
00:28:41
amount of water is
00:28:43
used if it is small then the amount of
00:28:47
the the size of the dam that you need to
00:28:49
create is also
00:28:51
small if it is large then you need to
00:28:53
create a larger Dam in order to have
00:28:55
that water availability all through the
00:28:57
year so at this stage we need to make
00:29:00
the actual planning of how big should be
00:29:03
the dam how big should be the how much
00:29:05
should be the water retention capacity
00:29:07
how big should be the turbine how big
00:29:09
should be the pain stock and all
00:29:11
that and finally the third stage is
00:29:26
the so this is actually the complete
00:29:30
detail planning of the
00:29:34
system I'll I'll I'll come to the the
00:29:36
details a little
00:29:40
later
00:29:46
so now let us come to the classification
00:29:49
of various types of hydric power plants
00:29:52
the classification is actually done from
00:29:54
two
00:29:55
angles number one
00:29:58
how big is the water retention
00:30:02
capacity uh if you ask that
00:30:05
question
00:30:08
uh num number
00:30:16
is water flow
00:30:19
regulation from this angle there are
00:30:22
three types
00:30:23
of hydric power PL really one are called
00:30:28
The
00:30:31
Run
00:30:34
of river power
00:30:37
plants this
00:30:45
is as the water comes you utilize it and
00:30:48
don't store anything many of the micro
00:30:52
hydal power plants that are situated in
00:30:54
the Himalayas for example the ones that
00:30:57
are now being installed in Assam in
00:30:59
megala in Manipur these places these are
00:31:02
of this type really you do not have much
00:31:05
of storage capacity when the water comes
00:31:07
utilize it that's
00:31:09
it these have obviously less
00:31:12
installation uh cost but then obviously
00:31:15
you do not have uh Power Generation some
00:31:18
of the times power generation
00:31:20
varies then
00:31:37
run of reer plants with small
00:31:40
storage again most of the hydro
00:31:44
hydroelectric plants that are situated
00:31:46
in elevated uh locations you do not have
00:31:49
scope of very large storage so you have
00:31:51
this
00:31:52
kind um have you ever visited any of the
00:31:56
Hill stations
00:31:59
huh most of you have right have you seen
00:32:02
any of these small hydroelectric power
00:32:05
plants most of the H sttion have because
00:32:08
there are small reviews small amount of
00:32:11
water available even that is enough for
00:32:14
generating power because of the high
00:32:15
head right very large head available and
00:32:18
therefore you can us utilize
00:32:20
that and the third type is the large
00:32:34
LGE T this type
00:32:36
PL for example the ones that are in myON
00:32:40
Panet U these are of this type right
00:32:44
within West
00:32:45
Bengal Bakr
00:32:47
angal the the one that is now being a
00:32:50
center of
00:32:52
controversy s Ser basically the ones on
00:32:55
NADA these things are the large stor
00:32:59
type
00:33:03
P so this is one kind of
00:33:06
classification the large power plants
00:33:08
are generally of this type and these two
00:33:10
are essentially the microh
00:33:13
hydal uh mini hydal or microh hydal
00:33:19
class the second classification comes
00:33:23
from the
00:33:24
head the
00:33:29
so in this you
00:33:37
have these are generally in the upper
00:33:40
reaches of the
00:33:41
Himalayas High head plants and you have
00:33:51
the plants and the
00:34:01
why is this classification needed
00:34:02
because in the high head plants normally
00:34:05
you will have them in the the upper
00:34:07
reaches of the Himalayas of the Hill
00:34:10
terrains you have a large head available
00:34:13
and in such cases it becomes
00:34:16
advantageous to First convert that into
00:34:19
the water's kinetic energy and utilize
00:34:21
that kinetic
00:34:22
energy in medium in in lwh head plants
00:34:25
you cannot really convert it into
00:34:26
kinetic energy
00:34:28
right if you put it in a nozle it will
00:34:30
only fall because low head the pressure
00:34:33
is low so in that case you have to
00:34:36
directly utilize the
00:34:37
pressure without converting into kinetic
00:34:40
energy so they these three types require
00:34:43
different types of turbines that is why
00:34:46
you have this different classification
00:34:48
mostly these things will have the class
00:34:50
of turbines that are called impulse
00:34:52
turbines so here you have impulse
00:34:55
turbines
00:35:01
where the water is FL allowed to pass
00:35:06
from a high head to the normal pressure
00:35:09
the atmospheric pressure through a
00:35:11
nozzle and that is allowed to impinge on
00:35:13
some you know cup like shapes that is
00:35:16
placed on the surface of the turbine and
00:35:18
the turbine rotates these are the
00:35:20
standard impulse
00:35:22
turbines these
00:35:23
are they have to use the reaction of the
00:35:27
directly without converting into kinetic
00:35:29
energy these are called the reaction
00:35:38
termines and in the medium head you have
00:35:41
certain special class of turbines that
00:35:44
are mean for medium head so uh called
00:35:49
Francis
00:35:50
turbines but the point is that if there
00:35:53
are very low head power plants then you
00:35:56
have also the
00:36:01
the then you have special class of
00:36:04
turbines which I'll deal with later when
00:36:07
we actually deal with the the subject of
00:36:11
tidal power generation which have very
00:36:12
low head then these are called the
00:36:17
the bulb
00:36:20
turbines or tube turbines
00:36:31
but at this stage it will make sense to
00:36:33
give you some idea about the
00:36:35
structure for example the impulse
00:36:37
turbines will have the structure
00:36:39
something like this you have got
00:36:42
a a circular shape and you have got
00:36:46
those cup like things
00:36:51
huh and there is a
00:36:55
nozzle which allows
00:36:59
the water to come out at high speed and
00:37:01
impinging on the wheel on the on the
00:37:02
cups which makes it
00:37:06
l okay so this is the standard structure
00:37:09
of the impulse
00:37:20
turbine
00:37:25
okay the standard structure of the the
00:37:28
reaction turbine is something like a fan
00:37:30
for example you can imagine it's it's uh
00:37:34
it's something like this
00:37:59
okay and you have the shaft of the
00:38:02
generator
00:38:03
there I'm drawing very simplified
00:38:06
diagram just to give you an idea in any
00:38:09
book on the turbines you will get a
00:38:11
better picture of it but presently I'm
00:38:13
trying to give you the essential feature
00:38:15
it's like a fan so as the water comes
00:38:17
and
00:38:19
flows the fan rotates and therefore you
00:38:22
can see that the fan is always in touch
00:38:25
with the water and you are not using the
00:38:28
kinetic energy water really you are only
00:38:30
using the pressure of the water flow of
00:38:34
the water to to make the turbine
00:38:40
rotate okay so this is generally used
00:38:43
for the low head and in for the medium
00:38:46
head there are a little bit of
00:38:48
complicated construction which is not
00:38:49
subject matter of this course because
00:38:51
most of you will learn
00:38:54
uh such structures in details in
00:38:57
mechanical
00:38:58
courses but you see here also you need
00:39:02
this amount of head in order to allow
00:39:05
the water to pass through because it is
00:39:08
placed
00:39:10
vertically and in very low head power
00:39:12
plants which are placed almost in plain
00:39:16
land there the amount of head available
00:39:18
is only a meter or
00:39:21
two in those cases obviously you cannot
00:39:23
have even this much
00:39:25
of height difference between the two
00:39:27
sides in those cases you have as we
00:39:31
called the bulb or tube turbines
00:39:35
where here the problem is that the thing
00:39:38
is placed in water but it has to be
00:39:41
connected to the shaft which is placed
00:39:44
has to be placed outside the water
00:39:45
because it has to be it is how generator
00:39:47
it has to be connected to the
00:39:48
generator so the generator has to be
00:39:50
placed outside the
00:39:52
water in this this particular design it
00:39:55
is vertically aligned so so that the
00:39:57
generator is placed up
00:40:00
here
00:40:02
but uh as I told you that if the hit is
00:40:06
too low then you cannot have even that
00:40:08
in that case what do you do you have a
00:40:10
straight flow
00:40:13
Channel and you can have say water is
00:40:16
Flowing this
00:40:22
way you can have the prop kind structure
00:40:24
like this
00:40:28
but then where do you place the
00:40:30
generator generator has to be placed in
00:40:32
the same
00:40:34
shaft which will be inside the water so
00:40:37
one creates a bulb like
00:40:46
structure in which the generate is
00:40:49
placed it is
00:40:53
uh this is completely um
00:40:57
uh water tight so that water does not go
00:41:01
in okay so that is why this is called
00:41:03
the bulb
00:41:18
turbine for very lwh head power plants
00:41:20
you have turbines of this kind of
00:41:24
shape these are called the bulb turbines
00:41:31
uh tube turbines are the ones where you
00:41:35
have the you allow the water to flow
00:41:38
through a channel place like
00:41:41
this place
00:41:43
the turbine
00:41:46
here and you make a shaft that goes
00:41:52
up and place the generator here
00:41:59
okay there another way to to have
00:42:08
it so this will be the structure of the
00:42:10
tube
00:42:22
terine clear that is why you had these
00:42:27
three classifications
00:42:32
of these four classification of
00:42:35
the the power plants depending on the
00:42:38
head because you need different types of
00:42:40
turbines for this
00:42:44
purpose I copied the
00:42:51
tuine now as we have
00:42:55
seen the hydr power can be used both
00:42:58
both as a b base load
00:43:00
plant as well as a peak load
00:43:03
plant so you might plan it to be used as
00:43:07
a Bas load plant because you have got
00:43:09
huge water availability I want to to use
00:43:11
all the water so that it is used as Bas
00:43:13
load
00:43:14
plant you may also use it as a peak load
00:43:17
plant right what will be the
00:43:20
difference suppose in a particular place
00:43:22
you have certain quantity of water
00:43:24
available all through the year and and
00:43:27
you have planned it to be a base load
00:43:29
plant and in another CL case you have
00:43:31
planned it to be a peak load plant what
00:43:33
will be the essential difference in in
00:43:35
in the planning it is that in case of
00:43:38
the Bas load plant it will be running
00:43:40
all the
00:43:41
time in case of the peak Lo plant it
00:43:43
will be tring only for say 20% of the of
00:43:46
the
00:43:47
day now this is expressed in a quantity
00:43:50
called the load Factor load factor means
00:43:54
load factor of power plant means uh
00:43:58
in the numerator it's it's a fraction in
00:44:00
which you have in the numerator the
00:44:02
amount of energy that is actually
00:44:04
generated in the denominator you have
00:44:07
the amount of energy that could have
00:44:09
been generated if it ran at full load
00:44:12
for the whole
00:44:13
time have you understood the so in case
00:44:16
of a base load plan what will be the
00:44:18
load Factor
00:44:20
100 100 one 100% in case of a peak load
00:44:25
plan it will be something like 20%
00:44:28
okay so the load Factor will be
00:44:32
different often you will find you'll
00:44:34
find referred the load Factor referred
00:44:37
in literature on power plants like this
00:44:40
power plant ran at something like6 load
00:44:42
Factor what does it mean it means that
00:44:45
even though it could have produced so
00:44:47
much power it did not because of certain
00:44:49
reasons either outage or some leakage or
00:44:52
some something due to which its actual
00:44:54
total energy production was less so the
00:44:57
that that was the load rate now suppose
00:45:00
let's let's do a simple uh
00:45:04
problem Suppose there is a
00:45:07
dam that has a sufficient water capacity
00:45:12
water retention capacity so that it can
00:45:16
produce
00:45:19
200
00:45:22
million kilowatt
00:45:24
hour per year
00:45:30
okay suppose you have got a dam that
00:45:33
retains sufficient amount of water so
00:45:35
that this amount of energy can be
00:45:37
produced per
00:45:38
year in one case you are designing a
00:45:41
base load plant in another case you are
00:45:44
designing a weak load
00:45:46
plant now if it is designed as a b base
00:45:50
load
00:45:51
plant what will be the power this is
00:45:55
energy what will be the power
00:45:59
so
00:46:01
if it
00:46:14
is then the
00:46:21
power it will be 200 million into 10^ 6
00:46:27
divided by the number of hours per year
00:46:32
which is do you know how much it
00:46:37
is 8760 is the number of years per
00:46:42
and this will be expressed
00:46:46
in kilow you like to express in
00:46:48
megawatts so divide
00:46:52
by how much will it be because you see
00:46:55
here the Ro factor is
00:46:58
one huh
00:47:00
so this is just the total amount of
00:47:03
energy divided by the
00:47:05
time how much is this can
00:47:08
calculate it will approximately come to
00:47:13
23
00:47:16
Mez okay it will approximately come to
00:47:19
23
00:47:22
Mez now if
00:47:27
check
00:47:29
that yeah 22.8 something
00:47:33
right as a peak load
00:47:40
plant
00:47:48
with load Factor
00:47:52
0.2 then how will we calculate that
00:47:58
power no not it not it will not be into
00:48:02
point2 yes so this will now
00:48:07
be this will now
00:48:13
be into five right how the same thing
00:48:20
23
00:48:24
now this will have to be multiplied by
00:48:27
100 by
00:48:30
20 so this will approximately be how
00:48:39
much so you see if you plan it as a peak
00:48:42
load plant it has it has to have much
00:48:44
more power capacity which means the
00:48:47
turbine should be larger which means the
00:48:50
the pen stock should be more will have
00:48:52
more diameter so all these will be
00:48:55
necessary that means a peak Lo plant if
00:48:57
you plan it as a peak load plant it will
00:48:59
have larger
00:49:00
investment it will require a larger
00:49:03
larger investment but still most
00:49:07
hydroelectric plants other than the
00:49:09
areas where it is huge amount of water
00:49:13
is available other than those areas uh
00:49:16
things are designed as Peak Lo plants
00:49:19
why because the advantage
00:49:22
is during the lean period you use it as
00:49:25
Peak Lo plant all right
00:49:27
but the same thing during the rainy
00:49:29
season can be used as a Bas load
00:49:31
plant right the same thing you have
00:49:33
already installed it you have already
00:49:35
installed it and during the rainy season
00:49:37
huge amount of rain is available so same
00:49:40
thing you run as a Bas Lo plant so that
00:49:43
the amount of cool that you use will be
00:49:46
less
00:49:47
overall that is why even though the
00:49:51
power produced the power necessary power
00:49:53
capacity necessary for a peak Lo plant
00:49:55
is so much larger there still we we use
00:50:00
most of the hydroelectric plants as Peak
00:50:02
Lo plants that means these are run only
00:50:06
during a part of the day when the peak
00:50:10
becomes the the load becomes goes to a
00:50:13
peak only at the time these hydric
00:50:16
plants are
00:50:17
run but in the rainy season they run all
00:50:20
the
00:50:21
time that clear that is how most of the
00:50:24
power plants run
00:50:29
one more thing before we stop today that
00:50:34
is the the structure of the plant then
00:50:37
would be that there are some
00:50:40
hills and you construct a
00:50:46
dam so that water
00:50:49
is stored
00:50:52
here then you have
00:50:55
a a tube running through which is called
00:50:58
a pain
00:50:59
stock the the water that goes through
00:51:03
and then at at at some
00:51:06
uh height below you have got the
00:51:10
turbine and the this discharge water
00:51:13
actually goes through the river these
00:51:15
are the essential
00:51:17
components you can understand the the
00:51:20
basic things from
00:51:22
this now you see
00:51:26
that there are various types of uh
00:51:29
various ways of creating the dam in very
00:51:31
crude uh microh hydral plants you can
00:51:34
this can even be simply some Boulders
00:51:36
placed with Clay but in most places you
00:51:38
have got concrete structures in any case
00:51:41
the the point is that the amount of
00:51:44
energy
00:51:52
available so here is the turbin
00:51:59
and this is the PIN
00:52:05
stop the energy available is as we have
00:52:09
seen it is Q
00:52:13
times uh the unit weight of water which
00:52:17
was GH so let's call it w times we set
00:52:22
the age
00:52:24
right h we had then missed out a
00:52:28
particular uh issue that is the
00:52:30
efficiency of the
00:52:33
system so the efficiency has to be
00:52:35
multiplied that is actually the energy
00:52:37
available but there's a point
00:52:41
here
00:52:43
here
00:52:45
now the difference in head from here to
00:52:51
here is the available head so let's call
00:52:54
it the the the gross
00:53:00
head let us call it this
00:53:03
HG but then because water goes through
00:53:07
this pain stock some amount
00:53:09
of head is lost there right in the sense
00:53:13
that uh after all when there's some loss
00:53:17
there and that loss there's a loss in in
00:53:21
getting into the pen stock there's a
00:53:23
loss in going through the pen stock
00:53:24
there's a loss in getting out of the pen
00:53:26
stock and then in the nozzle so all
00:53:28
these losses can be taken together as
00:53:30
some some kind of a loss of
00:53:32
head so the
00:53:36
the head
00:53:41
lost let's call it HF then this H is
00:53:47
actually HG minus HF so the actual
00:53:52
difference does not really translate
00:53:55
into power it will be be slightly
00:53:57
less and that less is the collection of
00:54:01
the losses in all the
00:54:03
systems right so when we calculate this
00:54:07
we'll have to take that into account
00:54:08
also clear okay so that is all for today
00:54:12
let us continue with this tomorrow
