Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, 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.

इंटरनेट मानक

“!ान $ एक न' भारत का +नम-ण”Satyanarayan Gangaram Pitroda

“Invent a New India Using Knowledge”

“प0रा1 को छोड न' 5 तरफ”Jawaharlal Nehru

“Step Out From the Old to the New”

“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan

“The Right to Information, The Right to Live”

“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam

“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 12800-1 (1993): Guidelines for selection of turbines,preliminary dimensioning and layout of surfacehydro-electric power houses, Part 1: Medium and large powerhouses [WRD 15: Hydroelectric Power House Structures]

IS 12800 (‘Part 1 ) : 1993

Indian Standard

GUIDELTNBSFOR SELECTJONOFTURBINES, PRELIMINARYDIMENSIONINGAND

LAYOUTOFSURFACEHYDRO-ELECTRIC POWERHOUSES

PART 1 MEDIUM AND LARGE POWER HOUSES

UDC 627.85 : 621.224~2

o BIS 1993

BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI I 10002

August 1993 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 will be different from large, medium and micro ( small ) Power Houses. Requirements are, therefore, 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 1 MEDIUM AND LARGE POWER HOUSES

1 SCOPE

This standard (Part 1) lays down guidelines for preliminary dimensioning for surface hydro- electric power houses with reaction turbines having vertical shaft arrangement.

NOTE - These guidelines will generally apply to unit capacities from 5 MW to 500 MW.

2 REFERENCES

The Indian Standards listed below are necessary adjuncts to this standard:

IS No.

4410 ( Part 10 ) : 1988

5496 : 1969

7418 : 1991

7326 ( Part 1 ) : 1992

12837 : 1989

7332 ( Fart 1 ) : 1991

Title

Glossary of terms relating to river valley projects : Part 10 Hydro-electric power station including water conductor system (first revision )

Guide for preliminary dimensioning and layout of elbow type draft tubes for surface hydel power stations

Criteria for design o’ spiral casing ( concrete and steel ) (first revision )

Penstock and turbine inlet butterfly valves for hydro- power stations and systems: Part 1 Criteria for structural and hydraulic design

Hydraulic turbines for medium and large hydro- electric powel houses - - Guidclincs for selection

Spherical valves for hydro- power stations and systems: Part 1 Criteria for structural and hydraulic design

3 TERMINOLOGY

3.0 For the purpose of this standard, the defini- tionsgiven in IS 4410 ( Part IO ) : 1988, IS 7418 : 1991 and following should apply.

3.1 Specific Speed ( n, )

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:

where

IZS =

Yl=

P= H=

specific speed of turbine in revolutions/ minute, rated speed of turbine in revolutions/ minute,

turbine output in kW, and 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 of type of turbine should be made in accordance 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 synchro- 110~s speed/rotational speed II’ can bc computed from the following formula:

.

IS 12800 ( Part 1 ) : 1993

where

II,’ = trial specific speed.

: 000

4.2.3 After mentioned determined

4.2.4 If on

determining the rated speed as above, the specific speed can be by the formula given in 3.1.

account of heavy silt abrasion is . apprehended then a lower value may be adopted.

4.3 Turbine Setting 600

500

400

* 200 w

g

z 100 9

I .

2 s! e 50 G (r 40

30

20

10

50 100 200 300 400 500 1 cm

SPECIFIC SPEED (ns~

FIG. 1 REL.~TIONSHIP BETWEEN SPECIFIC SPBED AND RATBD HEAD

4.2.2.3 The rotational/synchronous/rated speed of the turbine in revolutions per minute is determined from the following formula:*

60 x f Hated speed in r.p.m, II - ~--- P

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:

where Ha s Hb =

H, =

0=

H, < H,, -- oH - Hv

Suction head in metres; Barometric pressure in metres of water column;

Vapour pressure; and

( In the absence of specific data the value of Hb - H, can be determined from Fig. 2 for a given altitude above mean sea level and for a given tempera- ture which is generally taken as 30°C. )

Thoma’s cavitation coefficient, which can be obtained from Fig. 3A and Fig. 3B.

The positive value of Hs indicates that the centre line of the distributor may be placed up to Ha metres above the minimum tail water level. The negative value of Hs indicates that the centre line of the distributor is to be placed at an elevation of at least HB metres below minimum tail water level.

where

.f = frequency ia cycles per second ( In $ a.5

Indian Power systems, frequency - % 50 cycles per second ), and 5

a

]J - number of pairs of pOkS.

The selection of rated speed by the above ‘; formula is subject lo the following considera- $ 7 lions:

a)

h)

An even number of pairs of poles should be preferred for the generator, through standard generators with odd number of

-; 65

6

pairs of poles are also available; and z! g If the head is expected to vary less than

~~~~;~ - r 7 7. <\1

10% from the design head, the next ALflTClDE ABOVE SEA LEVEL (metres)

greater speed should be chosen. A head varying in excess of 10% from the design

FIG. 2 HEIGHT OF BAROMETRIC: WATER COLUMN

head suggests the next lower speed. AT DIFFERENT TEMPERATURES OF WATER AND

ALTITuDBS Anov~ SRA L~VFI.

2

600

60

IS 12800 ( Part 1 ) : 1993

': 04 006 008 01 02 03

THOMA’S COEFFICIENT

FIG. 3A THOMA’S COEFFICIENT AT DIFFBRL~NT SPECIFIC SPEED FOR FRANCIS TURBINE

ooc

800

600

500

400

0.3 04 05 06 07 08 09 10

THOMAS COEFFICIENT (0 1

FIG. 3B THOMA’S COEFFICIENT FOR DIPFBRBNT SPECIFIC SPEED FOR KAPLAN TURBINES

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 uneconomi- cal construction of power house, the specific speed may be reduced by decreasing the speed of rotation.

4.4 Runner

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 cocffi- cient K,, which is defined a’s:

x D I18

where D is & ia case of Francis turbine and D,: in case of Kaplan turbine.

The relationship between specific speed ( 11, ) of machine and peripheral vclocit>’ coefficient ( KU )

3

is shown in Fig. 5 for Kaplan turbines and in Fig. 6 for Francis turbines.

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.

4.5 Spiral Casing

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.

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

X$ 12800 ( Part 1 ) : 1993

KAPLAN -lbRBINE

FIG. 4 TYPICAL SHAPES OF REACTION TURBINE RUNNERS

22

2.0

18

1.6

14

1.2

300 400 500 fml 7OCJ 800 900 1000 11x

SPECIFIC SPEED rli

FIG. 5 RELATIONSHIP BETWEEN SPECIFIC SPEED ( nH ) AND PBRIPHERAL VHL()~~TY

COEFFICIENT k',, FOR KAPLI\N TURBINE

IS 12800 ( Part 1 ) : 1993

06

0 100 20Q 300 400’ 500

SPECIFIC SPEED ns

FIG. 6 RELATIONSHIP BETWBEN SPECIFIC SPBED ( ns ) AND PBRIPHBRAL VBLOCITY

COEFFICIENT K, FOR FRANCIS TURBINE

2.0

18

16

14

12

10

0.8

0.6

0.4

02

0.0 50 150 200 250

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

I- ++----I : D-1 - 5-J

FIG. 8 MAJOR DIMENSIONS OF THE SPIRAL CASING

be determined by the following formula: R = 1.6 D1, and B = R + KD1.

where

K = 0.95 for # = 180” to 200”, and

K = 1.1 for 4 = 200” to 225’.

The equation of semispiral is given below:

where

P=

KI, K, =

The values

P = K1 - KI -8’

radius of curvature of the semi- spiral at an angle 8 in radians, and

constants.

of constants K1 and K, can be evaluated by the following conditions:

P = R at 0 = O”, and

P- 0.5 x stayvane outside diameter at 0 = 4.

Stayvane outside diameter is ‘F’ as determined from Fig. 10.

4.6 Draft Tube

Major dimensions of the draft tube are given in FIG, 9 SPIRAL CASING DINENSIONS WII II Fig. 12 and should be determined in accordance with IS 5496 : 1969.

RESPECT TO RUNNER DIAMETER D, OR I),( AND SPECIFIC: SPEED 11~

6

5 MAIN PARAMETERS OF HYDRO- GENERATORS

5.1 Air Gap Diameter ( D, )

5.1.1 The air gap diameter ( see Fig. 13 and 14 ) can be determined from the following criteria:

a)

‘3

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. The maximum value of air gap diameter D, is governed by the maximum permissi- ble stresses in the rotor parts and rim and these are directly linked with the peri- pheral 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.

& 2.6 m 2.4 g 22 5 20 5 16

5 16

I 1.4

0 : 12

5 10 2 0.8 u OGL A I I / I a 50 100 150 200 2% 300 350 03

SPECIFIC SPEtD 71s

w 12 0,

5 10

4' 08 cc 7 06

14

50 100 150 200 250 'cjr, :;,r)

SPFCIFIC SPEED -:

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, TE 12

where

v, = maximum peripheral velocity in 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 1.8

ii 1.6

4 1.4

ii

1.2

a 1.0

ul 50 100 150 200 250 300 350

SPECIFIC SPEED ns

r\

r: 8 1.1

0) g 0.9 1.0

L g 0.7 0.8

zi 0.6 I ii 0.5

; 0.4

0 03

-f $ 0.2

I I I n U? 50 100 150 200 250 300 350

SPECIFIC SPEED ns

FIG. 10 SPIRAL CASING DIMENSIONS WITH RESPECT TO RUNNER DIAMETER & OR Dn AND

SPECIFIC SPEED ns

FIG. 11 CONCRETE SPIRAL CASING

IS 12800 ( Part 1 ) : 1993

1 OF GUIDE APPARATUS ----_-__

-+-----I H = Depth of the draft tube L = Length of the draft tube B = Width of the draft tube

FIG. 12 MAJOR DIMENSIONS OF 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:

D,, = D, (1 +-$-)metres

where p = number of pairs of poles.

FIG. 13 SUSPENDED TYPE CONSTRUCTION

7

.

IS 12800 ( Part 1) : 1993

i i , I

I I

FIG. 14 UMBRELLA/SEMI-UMBRELLA TYPE CONSTRUCTION

5.3 Stator Frame Diameter ( Df )

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 = ( Do + 1.2) metres.

can be determined by adding 2.3 to 2.8 metres IO the stator frame across flat dimensions ( Df ) i.e.

D, = ( D, + 2.3 to 2.8 ) metres

= ( D, + 3-S to 4.0 ) metres

Db = ( De + l-6 to 2.0 ) metres

= ( D, + 2.8 to 3.2 ) metres

5.5 Core Length of Stator ( L, )

5.5.1 Core length of stator L, ( see Fig. 13 and 14 ) can be determined by the following formula:

where

W = Rated KVA of machine, and

K, = Output coefficient to be determined from Fig. 16.

5.6 Leogth of Stator Frame ( Lr )

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.

Lt = ( L, + 1.5 to 1.6 ) metres.

5.7 Height of Load Bearing Bracket ( h, )

5.7.1 Height of load bearing bracket Hj C see Fig. 13 and 14 ) can be determined by the following formula:

5.4 Inner Diameter of Generator Barrel ( DI, )

5.4.1 Inner diameter ( DI, ) of generator barrel ( see Fig. 13 and 14 - Inner dimensions across aat faces in case of polygonal shaped barrel )

__-. hj = K V’ Df for suspended type construe-

tion, and

II~ = K 4 Dgfor umbrella type construc- tion.

NUMaER OF PAIRS OF POLES (P,

FIG. 15 MAXIMUM PEIUPHBRAL ROTOR VELOCI,~Y If, AT RATED SITED

8

where

K = 0.65 for load of less than 50 tonnes per arm of the bracket,

KG 0.75 for load of 50 to 100 tonnes per arm of the bracket, and

K I 0.85 for a load of 100 tonnes and above per arm of the bracket.

Load per arm of the bracket to be determined as given hereunder.

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.

5.9 Axial Hydraulic Thrust

Axial hydraulic thrust P,< on ihe turbine runner may be determined by the following formula:

PH =

where

K=

D1 =

H max =

K D,‘J H,,, in tonnes.

a constant to be determined from Fig. 17A and Fig. 17B,

inlet diameter of runner in metres, and

maximum head in metres.

IS 12800 ( Part 1 ) : 3 993

5.10 Weight of Generator Rotor

Weight W?: of generator rotor in relation with air gap diameter DR and active core length LC can be determined from Fig 18.

5.11 Weight of Turbine Runner

Weight of turbine runner can be determined from Fig. 19A and 19B.

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 DIMENSIONS OF POWER HOUSE

6.1 The overall dimensions of power house mainly depend upon the following:

a) Overall dimensions of the turbine, draft tube and scroll-case;

b) Overall dimensions of the generator;

c) Number of units in the power house; 2nd

d) Size of the erection 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 with- out impairing the operational and maintenance requirements.

OUTPUT COEFFICIENT, l<o

171~;. 16 DETERMINATION OF OUTPUT COBFFICIENT

IS 12800 ( Part 1 ) : 1993

0.40

0 35

0.30

0.25

0.20

0.15

0.10

0 05

0

50 100 150 200 250 300 350

SPECIFIC SPEED (n s)

FIG. 17A DETERMINATION OF AXIAL HYDRAULIC THRUST COEFFICIENT FOR FRANCIS TURBINE

I -

i-

)L

1 I

FIG. 17B DETERMIXATION OF AXIAL HYDRAULIC TI~RIJS~.COEFPXCIENT FOR KAPLAN T~JRRINH

IS 12800 ( Part 1 ) : 1993

2 4 6 8 10 12 14 it‘

AIR GAP DIAMETER (D Q ) IN METRES

FIG. 18 WEIGHT DkI OF GENERATOR ROTOR IN RELATION WITH AIR GAP DIAMETER D, AND

ACTIVE CORB LENGTH L,

6.2 Length of Power House axis of the machine. For determining the outer

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

dimensions of the generator barrel,- the inner diameter of the generator barrel may be increa- sed 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.

I I J (1 5 tl I a RUNNER DIAMETER (Dl) IN METRES

FIG. 19A RELATIONSHIP kk'WREN RUNNERWI-IGHT AND RUNNER DIAMETER FOR FRANCIS TURBINE

11

IS 12800 ( Part 1 ) : 1993

C 1 2 3 4 5 6 7 6

RUNNER DIAMETER (Dl) IN METRES

FIG. 19B RBLATIONSHIP BETWBBN RUNNER WEIGHT AND RUNNBR DIAMETER FOR KAPLAN TURBINES

6.2.2 The length of erection bay may be taken On the upstream side provision should be made as 1.0 to 1.5 times the unit bay size as per for the following: erection requirements.

62.3 The total length L of the power houses can then be determined as follows:

L = No x ( unit spacing ) + LB + K

where

a)

b)

cl

N,, = Number of units,

L, = Length of erection bay, 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.

d)

e)

NOTE - IZ)lle to special topographical tail water conditions it may become necessary to provide addi- tionzl unloading bay at different levels.

6.3 Width of Power House Super structure

A clearance of about I.5 to 2-O m for concrete the upstream of scroll case;

A gallery of 1.5 to 2~0 m width for approaching the draft tube manhole;

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;

A clearance of about l-5 to 2.0 metres for pressure relief valve in the scroll case, if required; and

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 con- sidering the layout of essential equipment and operational requirements.

For determining the width of the power house 6.3.1 The inlet valve gallery, if provided, can be

superstructure, the overall dimensions of the utilized for approaching the draft-tube man-hole

spiral casing and the hydrogenerator may be also and hence no separate gallery is needed for

drawn with respect to the vertical axis of the this purpose.

machine. Superstructure columns should be 6.3.2 The cirteria laid down in 6.3 gives the clear of the downstream extremities of the above drawn figure by about 2.0 to 2.5 metres.

internal width of the Power Honse ( exclutiing column width ).

12

.

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 determi- ned, as follows:

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.

FIG. 20 CROSS SB~TION THROUGH GENERATING UNIT

IS 12800 ( Part 1) : 1993

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 equip- ment viz. turbine runners assembly, rotor assembly and even entire generator stator.

b) Hauling the main transformer with bushing into the erection bay under E.O.T. crane girder.

c) Clearance required for untaking transformers.

d) Unloading of largest package from trailors. A height of 7 to 8.5 metres tween the top erection bay floor and highest hook level may be sufficient.

the

of

the be- the

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 depen- ding upon the width of the power house super- structure 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 the overall dimensions of the power house is given in Annex A.

ANNEX A

( Clause 6.4.3.2 )

TYPICAL EXAMPLE FOR CALCULATING THE OVERALL DIMENSIONS OF POWER HOUSE

A-l DATA

Type of Machine

Total Number of Machines

Unit Capacity Maximum Head

Rated Head

Minimum Head

Francis Turbine

4

100 MW 105 111

100 m 75 m

13

Barometric Pr-essure at Power IO m House site

Vapour Pressure at Power 0.4 m House site

Power Factor 0.9

A-2 SYNCHRONOUS SPEED

From Fig. 1, specific speed of machine may be taken as 205.

.

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

:. 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 - 18

= 166.7 r.p.m.

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 = ____.~. ._ cI 1005/4 194

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 a specific speed of 194 = 0.12

:. Hs < IO - 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, & =- 6o ( 2 gH)“‘6~& as in 7x I1

IS 12800 ( Part 2 ) : 1989.

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.

A-5 DIMENSIONS 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 c= I.57 x 3.7 = 5.81 m 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

H 6 1.2 x 3.7 = 4.44 m I- O-235 x 3.7 = 0.87 m L = 0.98 x 3.7 - 3.63 m

M = O-6 1 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:

Height of draft-tube at exit end 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 cxces-

sive, 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 111 kW :: 9.R x Q x i/ :c .,.,

14

IS 12800 ( Part 1 ) : 1993

where

Q = discharge in cumecs,

W A-7.5 Core length of stator ‘Lc) = K. Dg’ I,

H= rated head in metres, and r) = efficiency of machine.

Assuming efficiency of machine to be 0.9,

e 100 x 1 000 _._ __---_ = 113.5 cumecs

= -!GG x 100 x 0.9

where

W = 11000 kVA, K,, = 6.6 ( from Fig. 16 ), Dg = 8.1 metre

II = 166.7 r.p.m.

:. Velocity at the exit end of draft-tube,

V, = -a-&$-ic = 2.219 m/set.

L, 11 000

:. = 6.6 x (8.1)’ x 166.7 = 1’54m

Say 1.5 m

IO accordance with 2.5 of IS 5496 : 1969, mini- mum submergence at the outlet end of draft-

A-7.6 Length of stator frame ‘~~9

tube should be greater than 0.3 metre, or c L, + 1.5 to 1.6 m

Vc” ___ i e i_?f??.F -_ O-251 nl E 1.5 + 1.5 = 3.0 m

2g ’ ’ 2 x 9.81 A-7.7 Axial hydraulic thrust PH = KD$ Hmax Say 0.3 m. in tonnes,

Keeping bed slope 1 vertical to 10 horizontal at where the bottom of the draft-tube, the exit end of draft-tube will be 1.67 metres above the bottom

K = 0.19 from Fig. 17,

of draft-tube. Ds = 3.7 m, and

:. Top of exit end of draft-tube will be H max - 105 m.

1.67 + d1.65 = 6.32 m above the bottom :. PlI = 0.19 x 3.7 x 105 = 273 tonnes. of the draft-tube.

Since height of draft-tube below centre line of A-7.8 Weight of generator rotor Wn - 225 x 1.5 tonnes ( from Fig. 18 ) - 338 tonnes

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.

A-7.9 Weight of turbine runner = 23 tonnes ( from Fig. 19 ).

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

A-7 GENERATOR PARAMETERS

A-7.1 Air Gap Diameter ‘DR’

Total number of pair of poles = 18

Rated kVA of generator = 100 000/o-9 = 111 000.

From Fig. 15, Da = 8-i m

A-7.2 Outer core diameter D,

G I); ( 1 + -5 ) metres

_ 8.1 1 1. ’

_.XP 2x18) = 8,807 m

Say 8.8 metres.

A-7.3 Stator frame diameter Df

= D, + 1.2 metres = 8.8 t_ l-2 = IO.0 m.

A-7.4 Inner diameter of generator barrel Db - D, + I.6 to 2.0 m _: IO.0 + l-8 = 11.8 m.

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

K- 0.85 ( see 5.7.1 ).

:. hj = 0.85 dlO = 2.64 for suspended type construction, and

-_. = 0.85 4 8.1 == 2.42 for umbrella type

construction.

A-8 OVERALL DIMENSIONS OF POWER STATION

A-8.1 From Fig. 21 drawn in accordance 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 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 I.5 times the unit bay size = 1 x 17 = 17 m.

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 station = 4 x 17 + 17 + 4 = 89 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.

Distance of the inner face of upstream columns from the longitudinal centre line of machine = 6.5 ( extremity of draft-tube/scroll-case/

generator barrel ) + 4.00 ( For accommodating control valve; the same space can also be used for approaching draft-tube ) = 10.5 m.

A-8.2 Total height of machine ( see Fig. 20 )

= HI + H,

From the size of draft-tube as already calcula- ted in A-6, HI - 10.2 m.

Hz = Lr + hi + K ( see 6.4.2 ).

As already calculated, Lr = 3.0 metres and hj = 2.69 ( For suspended type machine ).

K = 5.5 to 7.0, Say 6.0 m.

:. H, = 3.0 + 2.69 + 6 :-= 11.69 m.

:. Total height of machine IO.2 -i- 1 I.69 - 21.89 m.

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.

All dimensions in millimetrrs.

FIG. 21 PLAN SHOWING MAIN DIMENSIONS OF UNIT BAY

16

IS 12800 ( Part 1 ) : 1993

--lo75o~-+.-d35oo

--13500--y SPIRALCASING

n

<ENSTOCK

’ Y

All dimensions in millimetres.

FIG. 22 CROSS SECTION OF POWER HOUSE

17

_~~~~ _ __.. ~_.. _

Standard Mark The use of the Standard Mark is governed by the provisions of the Bureau of Indian

Standards Act, 1986 and the Rules and Regulations made thereunder. The Standard Mark on products covered by an Indian Standard conveys the assurance that they have been produced to comply with the requirements of that standard under a well defined system of inspection, testing and quality control which is devised and supervised by BIS and operated by the producer. Standard marked products are also continuously checked by BIS for con- formity to that standard as a furlher safeguard. Details of conditions under which a licence for the use of the Standard Mark may be granted to manufacturers or producers may be obtained from the Bureau of Indian Standards.

ISareaa of Indian Standarda

BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promote harmonious development of the activities of standardization, marking and quality certification of goods and attending to connected matters in the country.

Copyright

BIS has the copyright of all its publications. No part of these publications may be reproduced in any form without the prior permission in writing of BIS. This does not preclude the free use, in the course of implementing the standard, of necessary details, such as symbols and sizes, type or grade Enquiries relating to copyright be addressed to the Director ( Publications ), BIS.

designations.

Review of Indian Standards

Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewed periodically; a standard along with amendments is reaffirmed when such review indicates that no changes are needed; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standards should ascertain that they are in possession of the latest amendments or edition by referring to the latest issue of ‘BIS Handbook’ and ‘Standards Monthly Additions’. Comments on this Indian Standard may be sent to BIS giving the following reference:

Dot : No. RVD 15 ( 1345 )

Amendments Issued Since Publication

Amend No. Date of Issue Text Affected

BUREAU OF INDIAN STANDARDS

Headquarters:

Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi 110002 Telephones : 331 01 31, 331 13 75

Telegrams : Manaksanstha ( Common to all offices )

Regional Offices 3 Telephone

Central : Manak Bhavan, 9 Bahadur Shah Zafar Marg 331 01 31 NEW DELHI 110002 331 13 75

Eastern : l/14 C. I. T. Scheme VII M, V. I. P. Road, Maniktola 37 84 99, 37 85 61 CALCUTTA 700054 37 86 26, 37 86 62

Northern : SC0 445-446, Sector 35-C, CHANDIGARH 160036 i 53 38 43, 53 16 40 53 23 X4

Southern : C. I. T. Campus, IV Cross Road, MADRAS 600113 i i

235 02 235 15 19, 16, 235 235 04 23 42 15

Western : Manakalaya, E9 MIDC, Marol, Andheri ( East ) j 632 92 95, 632 78 58 BOMBAY 400093 I. 632 78 91, 632 78 92

Branches : AHMADABAD. BANGALORE. BHOPAL. BHUBANESIIWAR. COIMBATORE. FARIDABAD. GHAZlABAD. GUWAHA'I‘I. I [YDERABAD. JAIPUR. KANPUR, LUCKNOW. PATNA. 1 H~IIUVAN,~~NTI-IAPURAM.