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मानक
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Whereas the Parliament of India has set out to provide a practical regime of right to
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in order to promote transparency and accountability in the working of every public authority,
and whereas the attached publication of the Bureau of Indian Standards is of particular interest
to the public, particularly disadvantaged communities and those engaged in the pursuit of
education and knowledge, the attached public safety standard is made available to promote the
timely dissemination of this information in an accurate manner to the public.
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“प0रा1 को छोड न' 5 तरफ”
“The Right to Information, The Right to Live”
“Step Out From the Old to the New”
Mazdoor Kisan Shakti Sangathan
Jawaharlal Nehru
IS 12800-1 (1993): Guidelines for selection of turbines,
preliminary dimensioning and layout of surface
hydro-electric power houses, Part 1: Medium and large power
houses [WRD 15: Hydroelectric Power House Structures]
“!ान $ एक न' भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
“Invent a New India Using Knowledge”
“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता ह”
है”
ह
Bhartṛhari—Nītiśatakam
“Knowledge is such a treasure which cannot be stolen”
IS 12800
(‘Part 1 ) : 1993
( Reaffirmed 2003 )
Indian Standard
GUIDELTNBSFOR SELECTJONOFTURBINES,
PRELIMINARYDIMENSIONINGAND
LAYOUTOFSURFACEHYDRO-ELECTRIC
POWERHOUSES
PART
1 MEDIUM AND LARGE POWER
UDC
HOUSES
627.85 : 621.224~2
o BIS 1993
BUREAU
MANAK
August 1993
OF
BHAVAN,
INDIAN
9
BAHADUR
STANDARDS
SHAH
NEW DELHI I 10002
ZAFAR
MARG
Price Group 8
Hydro-electric
Power House Structures
Sectional Committee,
RVD 15
FOREWORD
This Indian Standard ( Part 1 ) was adopted by the Bureau of Indian Standards, after the draft finalized
by the Hydro-electric Power House Structures Sectional
Committee had been approved by the River
Valley Division Council.
So far as to generate electrical energy from Hydroelectric
Power Houses, Selection of Turbines,
Preliminary Dimensioning and Layout is necessary in designing of such Power Houses, requirement
Requirements are, therefore,
will be different from large, medium and micro ( small ) Power Houses.
laid down separately for large and medium Power Houses and small Power Houses. This standard is,
therefore, formulated into three parts - Part 1 covering Medium and Large Power Houses, Part 2
covering Storage Power Houses and Part 3 Mini and Micro Power Houses.
Guidelines covered in this standard are applicable after fixing the data with regard to the capacity,
type, number of units and discharges.
Departure from the guidelines will be necessary to meet such
special requirements and condition of individual site based on judgement and experience.
_
For the purpose of deciding whether a particular requirement of this standard is complied with, the
final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in
accordance
with IS 2 : 1960 <Rules for rounding off numerical values ( revised )‘. The number of
significant places retained in the rounded off value should be the same as that of the specified value in
this standard.
IS 12800 ( Part 1 ) : 1993
Indian Standard
GUIDELINESFORSELECTION OFTURBINES,
PRELIMINARY DIMENSIONING
AND
LAYOUTOFSURFACEHYDRO-ELECTRIC
POWER HOUSES
PART
MEDIUM AND LARGE
1
POWER
HOUSES
1 SCOPE
3.1 Specific Speed ( n, )
This standard (Part 1) lays down guidelines
for preliminary dimensioning for surface hydroelectric power houses with reaction
turbines
having vertical shaft arrangement.
It is the speed in r.p.m. at which a turbine of
homologous design would operate, if the runner
were reduced to a size which would develop one
metric horse power under one metre head. tt is
given by:
NOTE - These guidelines
will generally
unit capacities from 5 MW to 500 MW.
apply
to
2 REFERENCES
The Indian Standards listed below are necessary
adjuncts to this standard:
Title
IS No.
Glossary of terms relating
4410
( Part 10 ) : 1988 to river valley projects :
10 Hydro-electric
Part
including
station
power
system
conductor
water
(first
revision )
5496 : 1969
preliminary
Guide
for
dimensioning
and layout of
elbow type draft tubes for
surface hydel power stations
7418 : 1991
Criteria for design o’ spiral
casing ( concrete and steel )
(first
7326
( Part 1 ) : 1992
12837 : 1989
7332
( Fart 1 ) : 1991
revision )
Penstock and turbine inlet
butterfly
valves for hydropower stations and systems:
Part 1 Criteria for structural
and hydraulic design
for
Hydraulic
turbines
and large hydromedium
houses - electric
powel
Guidclincs for selection
Spherical valves for hydropower stations and systems:
Part 1 Criteria for structural
and hydraulic design
3 TERMINOLOGY
3.0 For the purpose of this standard, the definitionsgiven in IS 4410 ( Part IO ) : 1988, IS 7418 :
1991 and following should apply.
where
IZS=
specific speed of turbine in revolutions/
minute,
Yl= rated speed of turbine in revolutions/
minute,
turbine output in kW, and
P=
H=
rated head in metres.
3.2 Minimum Tail Water Level
It is the water level in the tail race
at the exit
end of the draft tube corresponding
to a
discharge required to run one machine at no
load.
4 MAlN PARAMETERS
OF TURBINE
4.1 Type of Turbine
The selection
in accordance
of type of turbine should be made
with TS 12837 : 1989.
4.2 Speed
4.2.1 Rated head and output
per machine being
known,
suitable
speeds
rrom
economical
considerations
may be decided in consultation
with the manufacturer.
4.2.2 Alternatively, speed can be detcrmi~~etl by
the following steps.
4.2.2.1 Determine trial specific speed by Fig. I
corresponding to available rated head of site.
4.2.2.2 After ascertaining trial specific speed as
mentioned in the foregoing para. trial synchro110~s speed/rotational
speed II’ can bc computed
from the following formula:
.
IS 12800 ( Part 1 ) : 1993
4.2.3 After determining
the rated speed as
mentioned
above, the specific speed can be
determined by the formula given in 3.1.
where
II,’ =
trial specific speed.
: 000
4.2.4 If on . account of heavy silt abrasion is
apprehended
then a lower value may be
adopted.
600
4.3 Turbine Setting
500
4.3.1 In reaction turbines, the setting of turbine
with respect of minimum tail water level should
be fixed from the consideration
of cavitation.
The suction height of distributor
centre line
above the minimum tail water level can be
determined from the following formula:
400
*
w
200
H, < H,, -- oH -
g
z
100
Ha s
Hb =
Suction head in metres;
Barometric
pressure in
water column;
H, = Vapour pressure; and
9
I
.
2
s!
e
50
G
(r
40
Hv
where
metres
of
( In the absence of specific data the
value of Hb - H, can be determined
30
from Fig. 2 for a given altitude above
mean sea level and for a given temperature which is generally taken as 30°C. )
20
0=
Thoma’s cavitation coefficient, which
can be obtained from Fig. 3A and
Fig. 3B.
10
The positive value of Hs indicates that the
1 cm
200
300 400 500
100
50
centre line of the distributor may be placed
up to Ha metres above the minimum tail water
SPECIFIC
SPEED (ns~
level. The negative value of Hs indicates that
FIG.
1 REL.~TIONSHIPBETWEENSPECIFIC SPBED the centre line of the distributor is to be placed
at an elevation of at least HB metres below
AND RATBDHEAD
minimum tail water level.
4.2.2.3 The rotational/synchronous/rated
speed
of the turbine in revolutions
per minute is
determined from the following formula:*
Hated speed in r.p.m, II -
60 x f
~--P
where
.f = frequency
ia cycles per second ( In
Indian
Power systems, frequency 50 cycles per second ), and
]J - number of pairs of pOkS.
The selection of
formula is subject
rated speed by the above
lo the
following considera-
$
a.5
%
5
a
‘;
$
7
lions:
-; 65
a) An even number of pairs of poles should
be preferred for the generator,
through
standard generators with odd number of
pairs of poles are also available; and
If
h) the head is expected to vary less than
10% from the design head, the next
greater speed should be chosen. A head
varying in excess of 10% from the design
head suggests the next lower speed.
6
~~~~;~
r
7
7.
<\1
ALflTClDE
ABOVESEA LEVEL (metres)
FIG. 2 HEIGHT OF BAROMETRIC:
WATER COLUMN
AT DIFFERENTTEMPERATURES
OF WATERAND
ALTITuDBS Anov~ SRA L~VFI.
z!
2
g
IS 12800 ( Part 1 ) : 1993
600
60
':04
006
008
01
02
03
THOMA’S COEFFICIENT
FIG. 3A
THOMA’S COEFFICIENTAT DIFFBRL~NT
SPECIFICSPEEDFOR FRANCIS TURBINE
ooc
800
600
500
400
0.3
04
06
05
THOMAS
FIG. 3B
COEFFICIENT
08
07
(0
09
10
1
THOMA’S COEFFICIENTFOR DIPFBRBNTSPECIFICSPEEDFOR KAPLAN TURBINES
is shown
4.3.2 In case the turbine setting, to have a
cavitation free runner at a given specific speed,
is found to be very low resulting in uneconomical construction
of power house, the specific
speed may be reduced by decreasing the speed
of rotation.
Fig. 6 for
in Fig. 5 for Kaplan
Francis turbines.
and in
4.4.2 The other runner dimensions of Francis
turbine indicated in Fig. 4 may be obtained
with respect to the diameter D3 and specific
speed 17~ from the curves shown in Fig. 7.
4.4 Runner
4.5 Spiral Casing
4.4.1 The runner discharge diameter LJ~ for
Francis turbine and runner diameter & for
Kaplan turbine ( shown in Fig. 3 ) are both
determined by the peripheral
velocity cocfficient K,, which is defined a’s:
4.5.1 Mefallic Spiroi Ccrsitrg
Metallic spiral casing should bc ur;ecl for gross
heads generally above 30 metrcs.
The major
dimensions of the spiral casing indicated in
Fig. 8 may be obtained as a function of YIP,
refcrrcd to runner diameter I>, or D!: from the
curves shown in Fig. 9 and 10.
x D I18
where D is & ia case of Francis turbine
in case of Kaplan turbine.
turbines
and D,:
Concrete spiral
casing shouid bc designed in
accordance with lS 7418 : 1991. ‘l‘hc radius I( OF
the
inlet portion and the \l;idth B of the open
portion of the casing, indicxtcd in Fig. 1 I can
The relationship between specific speed ( 11,) of
machine and peripheral vclocit>’ coefficient ( KU )
3
X$ 12800 ( Part 1 ) : 1993
KAPLAN
FIG. 4
-lbRBINE
TYPICAL SHAPES OF REACTION TURBINE RUNNERS
22
2.0
18
1.6
14
1.2
300
FIG. 5
400
500
fml
7OCJ
SPECIFIC
SPEED
800
900
1000
11x
rli
RELATIONSHIP BETWEEN SPECIFIC SPEED ( nH) AND PBRIPHERAL VHL()~~TY
COEFFICIENT k',,
FOR KAPLI\N TURBINE
IS 12800 ( Part 1 ) : 1993
06
0
FIG. 6
100
20Q
300
SPECIFIC SPEED ns
RELATIONSHIP BETWBEN SPECIFIC
COEFFICIENT K,
400’
500
SPBED ( ns ) AND PBRIPHBRAL VBLOCITY
FOR FRANCIS TURBINE
2.0
18
16
14
12
10
0.8
0.6
0.4
02
0.0
50
200
150
250
SPECIFIC SPEED n,
FIG. 7
RUNNBR DIMBNSIONS WITH
RESPWT
TO THE DIAMETER L+ AND SPBCIFIC SPEED
FOR FRANCIS TURBINE
5
IS 12800 ( Part 1 ) : 1993
5 MAIN PARAMETERS
GENERATORS
5.1 Air Gap Diameter
OF HYDRO-
( D, )
5.1.1 The air gap diameter
( see Fig. 13 and 14 )
can be determined from the following criteria:
a) The air gap diameter D, should be large
enough to allow the turbine runner top
cover to pass through the stator bore.
This condition is likely to be limiting
only with large Kaplan turbines of low
speed where a clearance of at least 5 cm
should be allowed.
‘3 The maximum value of air gap diameter
D, is governed by the maximum permissible stresses in the rotor parts and rim and
these are directly linked with the peripheral
velocity
on runaway
speed.
Assuming the runaway ratio to be 1.85 to
2.3 for Francis turbine and 2.3 to 3.2 for
Kaplan turbine ( higher speed ratio for
lower head ) the value of maximum
peripheral
rotor
velocity V, at rated
speed can be read from Fig. 15.
I-
++----I
:
-
D-1
5-J
FIG. 8 MAJOR DIMENSIONSOF THE SPIRAL
CASING
be determined by the following formula:
R = 1.6 D1, and
B =
R + KD1.
where
&
m
g
5
5
2.6
2.4
22
20
5
16
I
1.4
:0
5
2
u
12
10
0.8
OGL
50
16
a
K = 0.95 for # = 180” to 200”, and
K = 1.1 for 4 = 200” to 225’.
03
A
I
I
100
150
200
2%
SPECIFIC
SPEtD
71s
150
200
250
/
I
300
350
'cjr,
:;,r)
The equation of semispiral is given below:
P = K1 -
KI -8’
where
P=
radius of curvature of the semispiral at an angle 8 in radians, and
KI, K, = constants.
The values of constants K1 and K,
evaluated by the following conditions:
P =
P-
can be
14
R at 0 =
O”, and
0.5 x stayvane outside
0 = 4.
Stayvane outside
from Fig. 10.
diameter
12
w
at
0,
5
4'
cc
7
diameter is ‘F’ as determined
10
08
06
50
4.6 Draft Tube
100
SPFCIFIC
Major dimensions of the draft tube are given in
Fig. 12 and should be determined in accordance
with IS 5496 : 1969.
FIG,
9
SPEED -:
SPIRAL CASING DINENSIONS WII II
RESPECT TO RUNNER DIAMETERD, OR I),( AND
SPECIFIC:SPEED 11~
6
IS 12800 ( Part 1 ) : 1993
This curve relates to sheet steels having a yield
point of 525 N/mm*. For better quality steels
peripheral velocity be increased in direct ratio
of yield strength. The peripheral velocity thus
settled,
the value of D, in metres can be
obtained from the following formula:
&=60x
v,
12
TE
where
velocity
peripheral
v, = maximum
metreslsec, and
n = rated speed of machine in r.p.m.
a
&
3.0
2
2.8
2
2.6
L
2.4
6
2.2
z!
2.0
i
in
1
-+-----I
1.8
1.6
ii
H = Depth of the draft tube
L = Length of the draft tube
B = Width of the draft tube
1.4
4
1.2
ii
a
ul
OF GUIDE APPARATUS
----_-__
1.0
50
100
150
200
SPECIFIC
SPEED ns
250
300
FIG.
350
12 MAJOR DIMENSIONSOF DRAFT TUBE
5.2 Outer Core Diameter ( D, )
Outer core diameter Do of the stator ( see Fig.
13 and 14 ) can be determined by the following
formula:
r\
r:
8
1.1
0)
g
0.9
1.0
g
L
0.7
0.8
zi
I
ii
0.5
D,, =
D, (1
+-$-)metres
where
p = number of pairs of poles.
0.6
;
0.4
0
03
$-f
0.2
n
U?
50
100
I
I
150
200
250
SPECIFIC
SPEED
I
300
350
ns
10 SPIRAL CASING DIMENSIONS WITH
RESPECTTO RUNNER DIAMETER& OR Dn AND
SPECIFICSPEEDns
FIG.
FIG. 11 CONCRETESPIRAL CASING
FIG. 13 SUSPENDED
TYPE CONSTRUCTION
7
.
IS 12800 ( Part 1) : 1993
can be determined
IO the stator frame
i.e.
D, =
=
Db =
=
,
I I
i i
by adding 2.3 to 2.8
across flat dimensions
( D, + 2.3 to 2.8 ) metres
( D, + 3-S to 4.0 ) metres
( De + l-6 to 2.0 ) metres
( D, + 2.8 to 3.2 ) metres
I
5.5 Core Length of Stator
( L, )
5.5.1 Core length
of stator
and 14 ) can be determined
formula:
where
W =
Rated
5.3 Stator Frame Diameter
( Do +
5.4 Inner Diameter
( Df )
Lt =
FIG.
15
determined
1.5 to 1.6 ) metres.
of Load Bearing Bracket ( h, )
Height
of load
bearing
bracket
Hj
13 and 14 ) can be determined
by the
following formula:
C see Fig.
hj =
__-.
K V’ Df for suspended
tion,
barrel
across
barrel )
NUMaER
and
be
5.7.1
Barrel ( DI, )
5.4.1 Inner
diameter
( DI, ) of generator
( see Fig. 13 and 14 - Inner dimensions
aat faces in case of polygonal
shaped
( L, +
5.7 Height
1.2) metres.
of Generator
to
Fig. 13
following
Length of stator frame Lf ( see Fig. 13 and 14 )
can be determined
by adding I.5 to I.6 metres
to the length of stator core i.e.
5.3.1 Stator
frame
diameter
Df ( see Fig. 13
and 14 ) ( across
flat dimension
in case of
polygonal
shape ) can be determined
by adding
1.2 metres to the outer core diameter,
D, i.e.
Df =
( see
of Stator Frame ( Lr )
5.6 Leogth
UMBRELLA/SEMI-UMBRELLA TYPE
CONSTRUCTION
L,
by the
KVA of machine,
K, = Output
coefficient
from Fig. 16.
FIG. 14
metres
( Df )
II~ =
OF PAIRS OF POLES
type construe-
and
K 4 Dgfor
tion.
umbrella
type
(P,
MAXIMUM PEIUPHBRALROTOR VELOCI,~Y If, AT RATED SITED
8
construc-
IS 12800 ( Part 1 ) : 3993
5.10 Weight of Generator Rotor
where
K =
0.65 for load of less than
arm of the bracket,
50 tonnes
per
KG
0.75 for load of 50 to 100 tonnes
arm of the bracket, and
0.85 for a load of 100 tonnes
above per arm of the bracket.
per
K I
Load per arm of the bracket
as given hereunder.
to
be
5.11 Weight
and
determined
5.8 Number of Arms of Brackets
The number
of the arms of the bracket
are to
be decided on the basis of the total load on the
thrust bearing that is maximum
hydraulic
thrust
of the turbine
runner
and weight of rotating
parts. Generally
4 to 8 arms of the bracket
are
taken.
Axial hydraulic
thrust P,< on ihe turbine
runner
may be determined
by the following formula:
in tonnes.
where
K=
a constant
to be determined
Fig. 17A and Fig. 17B,
of runner
in
D1 = inlet diameter
and
H max = maximum head in metres.
from
metres,
OUTPUT
171~;. 16
of Turbine
Weight
of turbine
from Fig. 19A and
Runner
runner
19B.
can
be
determined
5.12 Weight of machine rotating parts comprises
the weights
of rotor and runner.
Total
axial
load for use in the determination
of height and
number
of
load
bearing
brackets
should
comprise
the hydraulic
thrust and the weights
of rotor and runner.
6 OVERALL
HOUSE
DIMENSIONS
OF POWER
6.1 The overall
dimensions
of
mainly depend upon the following:
5.9 Axial Hydraulic Thrust
PH = K D,‘J H,,,
Weight W?: of generator
rotor in relation
with
air gap diameter
DR and active core length LC
can be determined
from Fig 18.
house
turbine,
draft
a) Overall
dimensions
tube and scroll-case;
of
b) Overall
dimensions
of the generator;
c) Number
of units
in the power house;
d) Size of the erection
the
power
2nd
bay.
NOTE -- Provision for inlel valve, erection 01‘ , otor
and untanking
of transformers
should be made in
such a \vay that the space required is minimum without impairing
the operational
and maintenance
requirements.
COEFFICIENT,
l<o
DETERMINATIONOF OUTPUT COBFFICIENT
IS 12800 ( Part 1 ) : 1993
0.40
0 35
0.30
0.25
0.20
0.15
0.10
0 05
0
100
50
150
SPECIFIC
FIG. 17A
SPEED
300
250
200
350
(n s)
DETERMINATION OF AXIAL HYDRAULIC THRUST COEFFICIENT FOR FRANCIS TURBINE
1
I
I
-
i-
)L
FIG. 17B
DETERMIXATION
OF AXIAL HYDRAULIC TI~RIJS~.COEFPXCIENT
FOR KAPLAN
T~JRRINH
IS 12800 ( Part 1 ) : 1993
10
8
6
4
2
AIR GAP DIAMETER
FIG. 18
12
14
it‘
(D Q ) IN METRES
WEIGHT DkI OF GENERATOR ROTOR IN RELATION WITH AIR GAP DIAMETER
D,
AND
ACTIVE CORB LENGTH L,
axis of the machine. For determining the outer
dimensions of the generator barrel,- the inner
diameter of the generator barrel may be increased by 0.5 to 15 m depending upon the size of
the machine. A clearance of l-5 to 2.0 m should
be added on either side of the extremities of
the above drawn figures to determine the unit
spacing. These clearances should be such that
a concrete thickness on either side of scroll
case should be at least 2.0 to 2.5 m in case of
concrete
scroll cases and 1.0 IO I.5 m in
case of fully-embedded steel scroll cases.
6.2 Length of Power House
It depends upon the unit spacing, length of
erection bay and the length required for the
E.O.T. crane to handle the last unit.
6.2.1
Unit
Spacing
For determining
the distance
between the
centre lines of the successive units? a plan
showing the overall dimensions of the spiral
casing, the draft-tube and the hydro-generator
should be drawn with respect to the vertical
I
FIG.
19A
I
J
(1
RUNNER
DIAMETER
5
(Dl)
tl
RELATIONSHIP kk'WREN RUNNERWI-IGHT
FRANCIS TURBINE
11
I
a
IN METRES
AND
RUNNER
DIAMETER FOR
IS 12800 ( Part 1 ) : 1993
C
1
3
2
4
5
RUNNER DIAMETER
6
7
6
(Dl) IN METRES
FIG. 19B RBLATIONSHIPBETWBBNRUNNER WEIGHT AND RUNNBRDIAMETERFOR KAPLAN TURBINES
On the upstream side provision should be made
for the following:
6.2.2 The length of erection bay may be taken
as 1.0 to 1.5 times the unit bay size as per
erection requirements.
62.3 The total length L of the power
can then be determined as follows:
a) A clearance of about I.5 to 2-O m for
concrete the upstream of scroll case;
houses
b) A gallery of 1.5 to 2~0 m width
approaching the draft tube manhole;
L = No x ( unit spacing ) + LB + K
for
cl In
case the main inlet valve is also
accommodated in the power house, a valve
pit of appropriate size should have to be
provided as per IS 7326 ( Part 1 ) : 1992
and IS 7332 ( Part 1 ) : 1991;
where
N,, = Number of units,
L, =
Length of erection
bay, and
d) A clearance of about l-5 to 2.0 metres
for pressure relief valve in the scroll case,
if required; and
K = Length required for the E.O.T. crane
to handle the last unit. Depending
upon the number and size of the E.O.T.
crane, this length is usually 3.0 to
5.0 metres.
NOTE - IZ)lle to special
topographical
tail
conditions it may become necessary to provide
tionzl unloading bay at different levels.
e) The spaces as indicated against item (a)
to (d) are supposed to be sufficient for
accommodating
the auxiliary equipment
also but may have to be reviewed considering the layout of essential equipment
and operational requirements.
water
addi-
6.3 Width of Power House Super structure
6.3.1 The inlet valve gallery, if provided, can be
utilized for approaching the draft-tube man-hole
also and hence no separate gallery is needed for
this purpose.
For determining the width of the power house
superstructure,
the overall dimensions of the
spiral casing and the hydrogenerator
may be
drawn with respect to the vertical axis of the
columns should be
machine.
Superstructure
clear of the downstream
extremities of the
above drawn figure by about 2.0 to 2.5 metres.
6.3.2 The cirteria laid down in 6.3 gives the
internal width of the Power Honse ( exclutiing
column width ).
12
.
IS 12800 ( Part 1) : 1993
6.4 Height of Power House
6.4.1 The
height of power house from the
bottom of the draft-tube to the centre line of
the spiral casing H, ( see Fig. 20 ), can be
determined
in accordance with IS 5496 : 1969.
The thickness of the concrete below the lowest
point of draft-tube may be taken from 1.0 to
2.0 m depending upon the type of foundation
strata, backfill conditions and size of the power
house.
6.4.2 The height of power house from the
centre line of the spiral-casing up to the top of
the generator H2 ( see Fig. 20 ) can be determined, as follows:
6.4.3 The height of the machine hall above the
top bracket of the generator depends upon the
E.O.T. crane hook level and the correspondmg
E.O.T.
crane rail level, and the clearance
required between the ceiling and the top of the
crane. Further the height should depend upon
the height of the service bay floor from where
the equipment is to be handled.
6.4.3.1 The E.O.T. crane hook level and the
corresponding
crane rail level are determined
by
providing
adequate
clearance
for the
following cases:
a) Hauling moving major items of equipment viz. turbine runners assembly, rotor
assembly
and
even entire generator
stator.
H, = Lt + hj + K
Lt and hj have been defined in 5.6 and 5.7.1
respectively.
The value of K may be taken as
5.5 to 7.0 depending upon the size of the
machine.
b) Hauling
the main
transformer
with
bushing into the erection bay under the
E.O.T. crane girder.
c) Clearance
required
transformers.
for
untaking
of
d) Unloading of largest package from the
trailors. A height of 7 to 8.5 metres between the top erection bay floor and the
highest hook level may be sufficient.
6.4.3.2 The height of the power house ceiling
above the highest level of the E.O.T. crane
hook may generally vary from 4 to 6.5 m depending upon the width of the power house superstructure and capacity of E.O.T. crane. Keeping
a clearance of O-3 metre between the highest
part of the gantry crane and the ceiling of the
power house. A typical example for calculating
FIG. 20 CROSS SB~TION THROUGH GENERATING the overall dimensions of the power house is
given in Annex A.
UNIT
ANNEX
A
( Clause 6.4.3.2 )
TYPICAL
A-l
EXAMPLE
FOR CALCULATING
THE OVERALL
POWER HOUSE
DATA
Type of Machine
Total Number of Machines
Unit Capacity
Maximum Head
Rated Head
Minimum Head
DIMENSIONS
Barometric Pr-essure at Power
House site
Vapour Pressure
at Power
House site
Power Factor
Francis Turbine
4
100 MW
105 111
100 m
75 m
13
OF
IO m
0.4 m
0.9
A-2 SYNCHRONOUS
SPEED
From Fig. 1, specific
be taken as 205.
speed of machine
may
.
IS 12800 ( Part 1 ) : 1993
Synchronous
speed of machine
ns . Hbl4
=L/ P x l-358-
[ Same as adopted
by IS 12800 ( Part 2) : 1989 1.
where
n, =
205 r.p.m.,
H =
100 m, and
P=
100 xl
OOOkW
A-5 DIMENSIONS
:. Trial synchronous speed machine
205 x 1005/r
- v 106 x 1.358
= 176 r.p.m.
Synchronous
speed for 18 pairs of poles
60 x 50
zzz = 166.7 r.p.m.
18
Synchronous
speed for 16 pairs of poles
60 x 50
16
= 187.5 r.p.m.
As the head variation from the rated head is
mOre than 10% lower synchronous speed i.e. a
synchronous
speed of 166.7 r.p.m. is being
adopted.
:. Corrected
specific speed
166.7 4 106:358 ._
= ____.~.
1005/4
cI 194
A-3 TURBINE SETTING
Hs <
Hb-
aH-HH,
Here
Hb =
10 m,
H,
O-4 m
=
H =
105 m,.and
G m from Fig. 3 corresponding
speed of 194 = 0.12
:. Hs < IO < -
a specific
0.12 x 105 - 0.4 m
3-O m.
With a further margin of 0.5 met% the centre
line of the distributor should be set 3-O + 0.5
= 3.5 metres below minimum tailrace level as
defined in 3.2.
A-4 SIZE OF RUNNER
Discharge
diameter,
where
H = 105 m,
n = 166.7, and
Ku = from Fig. 6 corresponding to a specific
speed of 194 = 0.71
o3 60 ( 2 x 9.81 x 105 )O*t
_-.- x 0.71
:*
~-2.14
x 166.7
= 3.69 m.
Say 3.7 metres.
& =- 6o ( 2 gH)“‘6~& as in
7xI1
IS 12800 ( Part 2 ) : 1989.
OF SPIRAL CASE
As the gross head above the turbine is more
than 30 metres, metallic spiral casing should be
used. The main dimensions of the spiral casin
as determined
in accordance
with Fig. 8, f
and 10 work out to be as shown below:
A = I.1
x 3.7 = 4.07 m
B = 1.39 x 3.7 = 5.14 m
I.57 x 3.7 = 5.81 m
c=
D = 1.74 x 3.7 = 6.44 m
E = 1.29 x 3.7 = 4.77 m
F = 1.65 x 3.7 = 6.11 m
G = I.38 x 3.7 7 5.11 m
x 3.7 = 4.44 m
H 6 1.2
I- O-235 x 3.7 = 0.87 m
L = 0.98
x 3.7 - 3.63 m
M = O-61 x 3.7 = 2.26 m
A-6 SIZE OF DRAFT-TUBE
The various dimensions of the draft-tube shown
in Fig. 12 as determined
in accordance with
IS 5496 : 1969 should be as below:
end
draft-tube
at
exit
Height
of
h = 0.94 0s to 1.32 &.
As the specific speed of the turbine is on the
lower side, ‘h’ will be on the higher side.
Taking it _ 1.25 J!&, h = 1.25 x 3.7 =
4.65 m
Depth of draft tube ‘Iit’ for Francis Turbine
= 2.5 to 3.0 Dy.
Taking H1 5 2.75 D3, NL = 10.2 m.
Length of draft-tube Z_ = 4 to 5 &.
Taking L = 4.5 Dj, L r 4.5 x 3.7 =
16.70 m.
Cleat width ‘B’ of the druft-tube at exit end
= 2.6 to 3.3 Da.
Since the clear width of the draft-tube is cxcessive, a pier til‘ 1.5 metros \vidth shuulti be
introduced in the cenlrc of the drnft-tube.
The
total width of the ciraft-tub:
n.iII.
t!l~.l.,,
be
12.5 m.
Since, power 111kW :: 9.R x Q x i/ :c .,.,
14
IS 12800 ( Part 1 ) : 1993
where
W
K. Dg’ I,
A-7.5 Core length of stator ‘Lc) =
Q = discharge in cumecs,
H=
rated head in metres, and
r) = efficiency of machine.
where
W =
K,, =
Assuming efficiency of machine to be 0.9,
100 x 1__---_
000
= 113.5 cumecs
e = -!GG_._
x 100 x 0.9
Dg =
II =
:. Velocity at the exit end of draft-tube,
V, = -a-&$-ic
= 2.219 m/set.
Vc”
___ i e i_?f??.F
’ ’ 2 x 9.81
2g
Keeping bed slope 1 vertical to 10 horizontal at
the bottom of the draft-tube, the exit end of
draft-tube will be 1.67 metres above the bottom
of draft-tube.
:. Top of exit end of draft-tube will be
1.67 + d1.65 = 6.32 m above the bottom
of the draft-tube.
Since height of draft-tube below centre line of
guide apiaratus is 10.2 metres and the centre
line of guide apparatus itself is 3.5 metres below
minimum tail water level, the top of the exit
end of draft-tube will be ( 3.5 + 10.2 - 6.32 )
= 7.38 metres below minimum tail water level,
which is in order.
PARAMETERS
A-7.1 Air Gap Diameter ‘DR’
Total number of pair of poles = 18
= 100 000/o-9
Rated kVA of generator
= 111 000.
From Fig. 15, Da = 8-i m
A-7.2 Outer core diameter
I);
D,
( 1 + -5
_ 8.1
A-7.6 Length of stator frame ‘~~9
c L, + 1.5 to 1.6 m
E 1.5 + 1.5 = 3.0 m
A-7.7 Axial
in tonnes,
PH = KD$ Hmax
K =
0.19 from Fig. 17,
3.7 m, and
105 m.
:. PlI = 0.19 x 3.7 x 105 = 273 tonnes.
A-7.8 Weight of generator rotor Wn 1.5 tonnes ( from Fig. 18 ) - 338 tonnes
A-7.9 Weight of
( from Fig. 19 ).
turbine
225 x
runner = 23 tonnes
A-7.10 Height of load bearing bracket ‘hi’ =
Total weight of rotating parts + axial thrust
= 338 + 23 f 273 w 634 tonnes.
Let there be 6 arms in the bearing bracket,
634
Load on each arm - 6
= 105.7
Say 106 tonnes.
Height of load bearing bracket ‘hj = K J-i%
for suspended type construction,
and
= JKZ,
for umbrella type construction
where
K0.85 ( see 5.7.1 ).
= 2.64 for suspended type
:. hj = 0.85 dlO
construction, and
-_.
= 0.85 4 8.1 == 2.42 for umbrella type
construction.
= 8,807 m
A-7.3 Stator frame diameter Df
= D, + 1.2 metres
= 8.8 t_ l-2 = IO.0 m.
barrel Db
D, + I.6 to 2.0 m
of generator
-
thrust
Ds =
H max -
) metres
1 1. _.XP
2x18)
’
hydraulic
where
Say 8.8 metres.
A-7.4 Inner diameter
11 000
6.6 x (8.1)’ x 166.7 = 1’54m
Say 1.5 m
-_ O-251 nl
Say 0.3 m.
G
8.1 metre
166.7 r.p.m.
:. L, =
IO accordance with 2.5 of IS 5496 : 1969, minimum submergence at the outlet end of drafttube should be greater than 0.3 metre, or
A-7 GENERATOR
11000 kVA,
6.6 ( from Fig. 16 ),
_: IO.0 + l-8 = 11.8 m.
A-8 OVERALL DIMENSIONS
STATION
OF POWER
in accordance
A-8.1 From Fig. 21 drawn
with 6.2.1, the extremities
of scroll case/draft
tube/generator
in longitudinal direction are at
15
IS 12800( Part 1 ) : 1993
7-l 15 on spiral inlet side and 6.5 m on opposite
generator barrel ) + 4.00 ( For accommodating
control valve; the same space can also be used
for approaching draft-tube ) = 10.5 m.
side of the transverse centre line of the machine.
Adding l-5 to 2 metres to these dimensions, the
size of the unit bay in longitudinal direction or
unit spacing work out to be 17 metres.
Length of erection bay = 0.7 to
unit bay size = 1 x 17 = 17 m.
A-8.2 Total height of machine ( see Fig. 20 )
= HI + H,
From the size of draft-tube
ted in A-6, HI - 10.2 m.
I.5 times the
Space required for the E.O.T. crane to handle
the last unit will depend upon the number and
size of the crane.
For preliminary
purpose
assuming it to be 3 to 5 metres ( 4 metres in the
present case).
Total length of power
+ 4 = 89 m.
station
calcula-
Hz = Lr + hi + K ( see 6.4.2 ).
As already
calculated,
Lr = 3.0 metres
hj = 2.69 ( For suspended type machine ).
K =
= 4 x 17 + 17
and
5.5 to 7.0, Say 6.0 m.
:. H, = 3.0 + 2.69 + 6 :-= 11.69 m.
From Fig. 21 and 22 and 6.3, the distance of the
inner face of downstream
columns from the
longitudinal centre line of machine works out
to be 6.5 + ( 1.5 to 2.0, Say 2.0 ) = 8.5 m.
:. Total height
21.89 m.
All dimensions
of machine
IO.2 -i- 1 I.69 -
A-8.3 Total height of machine hall will depend
upon type of foundation,
height of E.O.T.
crane, size of assemblies, type of roof and can
be determined accordingly.
Distance of the inner face of upstream columns
from the longitudinal centre line of machine
= 6.5 ( extremity
of draft-tube/scroll-case/
FIG. 21
as already
in millimetrrs.
PLAN SHOWING MAIN DIMENSIONS OF UNIT BAY
16
IS 12800 ( Part 1 ) : 1993
--lo75o~-+.-d35oo
--13500--y
SPIRALCASING
n
<ENSTOCK
’ Y
All dimensions
FIG. 22
CROSS
in millimetres.
SECTIONOF POWERHOUSE
17
_~~~~ ___..
~_..
_
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