Raabe J. Hydro power - the design, use, and function of hydromechanical, hydraulic, and electrical еquipment

Fig. 10.3.7. b) Sectional drawing of vertical shaft

FT

at Guri, 2nd polvcr house, Rio Carorli.

\lcnczuela (owner

Corporation

Vcnezolana dc Guayana, Republic of \lcnc~~~cla) built by

Hit;~s;hi

Ltd, Japan.

H

=

11

l

to 146

m,

P

=

476 to 730 MW continuous, temporary output

767

Mi\'.

n

=

112,5 rpm. After previous designs, commissioncd bctwccn 1968 and

1977

\vith outpt~ts

of

P

=

218 to 400

M

W

at heads of

H

=

11

5

m to 136

m,

thesc 10 units. commisioned

198

1

arc at

present the

most potverful

FTs

built in Japan. Simplified design \vith par:tllc.l p1;1ic spiral c;ising.

conical hub, slag-welded shaft. The runner is a onc-piece casting of 13

%

Cr

-

1

"/o

Ni stainless stes!.

Iodate the largcst of this kind in the \vorld of 7,17 n1 outermost diametcr, and a tveight of

130

tonr.

For these machines the hcad of the Guri plant has becn increascd from

11

1

m

to

146

m

by increasing

the crest height of the concretc gravity dam. The submergence equals that of the prcvious design,.

According to the author's in~pression on sitc, the 400 MW FTs showed bad cavitation pitting after

one

ycar of full load operation under the smaller hcad of

11

I

m. (Drawing courtesy Hitachi, Ltd.

Japan.)

Fig.

10.3.7. a) Sectional drawing of vertical shaft FT at Hbrspranget, 1,ulc river: Swedcn (owncr

Swedish state power board) 4th unit built

by

KaMeWa

AB,

Kristineham, Stvcdcn.

H

=

103

m.

P

=

182,8

MW,

n

=

166,7

rpm. Runner throat diameter Dl

=

4,235 m. For I~ighest reliability the

stay vanes were inscrtcd into corresponding holcs

of

the stay rlng weldcd from steel plater. ant1 tlrcr!

connected with thc wetted face of the stay ring on both sides by means of a corner \veld. When

commissioncd in 1952 thc

average

annual prodxtion of 2020 GWh of Hirsprangct made a contri-

bution of

more than

2G%

o: Sweden's electricity production. With an extension in

1974

to

SO

the

Production of Hirsprangct ;:.as raised to 2240 GWh and the installed capacity to

935

hIW.

Thc

lasi

and

5th

unit then installed by KaMcWa

had

an output of

P

=

450

bIW

(n

=

83.3 rpm) with an axial

tons, and was since that time the most

powcrful hydro turbine in Europe. The water

s usual in Sweden) of a vertical penstock to the underground power station

and

a

very

1

tailrace

tunnel with an upstream gate. A 400

kV

AC

transnlission linc

with

a Icngth

first of its kind in the world was built in 1952 from Hirsprangct to central Swedcn.

locatio~l (north of thc Arctic Circle) and the need

fo;

expcrienccd and skilled

town with the ncccssary social

scrvices had

13

be built at sitc. Thc town

m"sistcd of houses for 1200 employees and their families in all 2200 people. as well as shops,

bs~itnls, post

and

police station, other social services such as sport and leisurc htcilitics and church.

'Dr

wing courtesy KaMcWa

AB,

Kristincham, Sweden.)

p

Fig. 10.3.8. Elcv:~tion

of

tl;c

IT

1tap;iric;l. rio Siio I~rnnciscc, 13rnzil lowncr Colnpanhia tIidroe1C.c.

[ricn tlo

Siio

Franciscc.)

In

sets (design I-l).dronrt. hliian).

11,

=

53,2

m;

ti

=

Y

1.8 rpnl;

P,

=

264

MW.

Spirai casing p:~ral!cl pliltc

rype

ol'stccl plates \veldcd

on

site, inlet cliutncter

'1.5

ni. Kunncr made

up

by

ncldin!; \vith ccp;i::l!c c:~rbo!l stccl b!arlus,

7.925

ni ili;~rnetcr, weight

IS@

tolls. Thrnst bearing:

1600 tons load.

\.ia tr~~ricated cone on [lie licad cover, with high prcssurc oil i~~jcction. (Drawing

courtcyy CIydroart. \,lilan, Italy.)

the ranner

vanc

channels. especially the inlet edge of the runner vaces. In a

PT

such

dal-rlage

is

restricted

tc

the mouth of the nozzle, the point of the niedle and the cutting

edsz

anti

the jet crltout of the bucket. As these mcrnbers are much easier to get at any

revision is

~nuch casier in a PT.

Thc dismantlins

and

cxchi~nge of

a

PT's wheel need much less time than that of a

FT

runner. Also thc repairs of

a

PT,

e.g.,

the wclding and the buildirig up welding and

grindi!~g

of

a bucket of

~1

PT

is m~lch easier to carry out and to check tllari the correspond-

ing repair on a FT runner.

d)

I11

the case of very small output the application of a

FT

would lead to rotational speeds

above the upper limit of

a

two-pole alternator. The reciuction gear then needed would

raise the price of

a

FT

set, whence

a

PT

with its red~iced speed is preferably employed.

Sorile

S~IC~L

ill1

I.CUI(~I-~S

~*oi~c~c~rniit,q

Peltnil

rlrl-bines:

The

Peltori turbine. not especially treated here, is usually considered a safe machine. But

it

certainly has some problems. One problem, namely sand erosion occurs mainly on

needle and nozzle

anti can be attributed to the high velocities there. It increases roughly

with the

2nd to 3rd power of the head, and with the occurrence of hard ingredients

in

the

water such as quartz.

In some cases sand erosion cannot

bc

eliminated even by means of sand separators

at

the

fig.

l().3.T

I'rojcct

of

n

high

hcatj

l,.r;l~~cis pt~~nl>-turl,il~c

1000

rn.

Xl;~chinc in

I31

.-

I

tank:

cylindric;ll

pier

From

11:

dlric,

or

ul.:

Single-

2nd multi-st:lge

pump-turhines for high

head

storagc plants. Paper

,4~31E

Pump turbinc

$hcmcs.

171uids E~ginecring

conf.,

Niagara Falls,

New

I'ork

1979.

110.1

533

(Draw-

,

courtesy Sulzcr

Escher

mc

\\'J'~~.)

~ntrtke. In this casc the sand particles are so small as to be kept suspended by Brownian

motion of the

surrcunding liquid

e.g.,

glaciated rock.

Another

problcm

is

the erosion by

a

droplet impact. It corresponds essentially to that

by

avitation. Moreover droplcts increase disk friction, when they impinge on the wheel with

r

slip

in

the tangential direction

(Cap.

5.5).

An

erosive droplct impact prcferably occurs on the back of the buckets, close to the cut

oul.

This originates from the wheel's overtaking slow droplets. Such detrimental droplets

rcsult

from

:

I)

slow fluid particles at the outer edge of the jet, especially when the bucket cut out

is

100

narrowly spaced,

3

droplets that are discharged from neighbouring buckets in the case of more than one

it,

1)

droplets that are reflccted from a casing

wall

too near to the wheel.

0

droplcts reflected from a tailwater surface which is not sufficielltly away from the

bottom

of the wheel.

the laiter factors increase their detrimental influence decisively with the flow rate and

@mewhat

wvjth the hcad, but also when the bucket's cut out edges are too close to the

of

the jlet.

e free height of

a

Pclton wheel and the spacing of its casing should

be

the number of jets, and with the jet to wheel diameter ratio.

kuse dthe two bcnds in series and in different planes, upstream of the nozzle within

hmain'of a

PT

with vertical shaft, the formation of a streamwise vorticity in the main

459

Fig. 10.3.10. Elevation of a FT in thc peak load and pumped storage plant Kosshag, Zemm, Tyrol,

Austria (owner

Taucrnkraftwerke

AG,

Salzburg)

4

scts (FT design Sulzcr Escher Wyss and hlaschi-

nenLlbrik lindritr, Graz, Austria). Shaft end passing the draft tube bend, during pumping engaged

\\.it11 the 2-stage single

flow

storage pump

by

a gear coupling and torque converter (design Voith).

H,.,

-

672 m;

r=

750 rpm:

1:

=

55,2

MW.

Spiral czsing welded plate design, welded on cast stay

vane

ring. Gate with stem in

2

bearings, overhung design. Integrally cast runner of stainless steel

CrjNi with staged and staged comb labyrinths. Labyrinth teeth in the comb labyrinth on the shroud

with larger

cienrance towards thc shdft for damping the bendilig oscillations of thc latter. Due to a

bad weather.

da~nmaging the sand trap of

a

tunnel feeder, the distributor has been badly eroded.

Henceforth

its walls were lined with resistant material. On the one hand the through-shaft to storage

pump decreases the efficiency only slightly (small value of

Kc:,),

on the other hand it stops the

formatioa of surging draft tube vortex. (Drawing courtesy hlaschinenfabrik Andritz and Sulzer

Escher Wyss.)

-

-"rZruF.-T-d

?y

--

yx-vc=

.

*./zY=--

'-.

-33-

>'

/

'

-2'

92

O

<..

=,Y

-*

1

,s,

I

+

-'a;-

:3

,'

,,>,.

.'<-

.

,.,;

4;

-,

//,/J

.,-

*;

.

.;y

,>

=@..

'-\

i

,

',','*

f

'

..a,

%.

*>

3

*-.-y-

-,

,

*-,\

1

I

>

,t

%

-

1

"-

.-

3

<,,

3

.

%

':

1):

-

"

rX

..

?

-

;

-.

'?

rt'

,

i

;

'+,--

.

>

-1

\

-\_

?

!

I

i

I

I,

-

*

-I

1

i

I,

.

-

p

'

i

1

...

'I

.

..,

1'

.

'-

..

i

2.

A.

>

#.

,

.

i

i;

I

-t

'.,

-a.

.

-

.--

.

\

%'

i

*.''%.

--;-.

-

'

-.

-*

L.

_

i

--*a*---

,

-

.

.z~---~

-

#.

-

-'

Fig.

10.3.1

1.

Model runner of the

FT

at tliiuslinp, Ziller, Tyrol, Austria (o\vner Taucrnkraftwerke

AG,

Sallburg)

2

sets peak load and pumped storage plant, FTs built

by

Sulzer Escher Wyss,

Switzerland. Data of prototype:

H

=

620 to

744

m;

n

=

600 rpm;

P

=

180

MW.

Runner:

D

=

2,767

rn.

To

date the

FT

\+ith the highest hcad in the world.

,I

.

H

-

P

amounts only

PO0/0

of

that

d

Wehr (Fig.

10.3.12),

but is

380%

that of Rosshag.

The

product

n

-

H

.

P

of Wehr is 160% that of

Grand

Coulee Ill, and 330% that of Churchill Falls. Scroll casing of rolled steel plates with high

Ykld point, spot-welded on integrally cast 10-vane stay ring of stainless stcel. Pseudo parallel plate

design

as

in Fig. 1.6.4

b.

(Photograpti courtesy Sulzer Escher Wyss arid Andritz.)

flow

of the nozzle is favoured (Cap.

7.2).

Thereby the acceleration of flow in the nozzle

Urains the streamwise vortex filaments. This increases the kinetic energy of the latter, lost

for

shaft

work.

Thereforc eflorts should

be

made in the design to ~ninimizc this effect by

avoiding too strong a curvature of the main in planes inclined to each other and by

aequate flow admission (Cap.

3.4).

he

above mentioned loss in the nozzle of an impulse turbine seems to be the reason for

a

negative scalc effect in the overload range (Cap.

5.5).

Hence

a

prototype's efficiency

YY

drop below that of the model, but curiously usually only at overload.

me

Cross

flow

on the bucket (Cap.

5.5)

as mother source of this loss behsviour should

Fig.

10.3.12. Horizonial high head

FT

of thc ternzry pumpcd storagc plant Wchr, Wehra, West

Gcrmnny (owncr Scliluclissc

AG,

Freiburg).

4

sets with FTs built by Sulzer Esclicr Wyss and

4

2-?!age

tlouble flo..v storage pumps with torclue converters built by Voith (see Fig. 1.6.4

a).

Horizon-

tal

shalt, dctachablc during pi~niping by means of an overriding clutch.

FT

for

H,,

=

645

m;

rr

=

6OU

rpm;

=

257.5

XIW.

Runner:

D

=

2,685

m. To date the FT with tlic largest

H

.

n

.

P.

/llt~rn:i~o: with air-cooled rotor and water-coolcd stator. Initial troubles with stator laminations

hcattxl too ~nucli. ;~nd 11;11rlj1ic cracks in the stay vanc'part hint at

3

limiting hydro-clcctric design

in 1972. Thc v;~ryin= span of the stay vanes rcquircs a carefill strcss calcuiation also with respect to

frlrig~~e cffcct. sce

Greiir

[10.127]. Bccausc of the high vclocitics, wcar of wctted parts cncountcred

by

c;3rcl'ul niatcrial selcction. Runner

1

and rotary labyrinth rings: integrally cast of Cr/Ni 1314 steel.

Stationary

eschanpnble lining around runner in rcgions

01

high velocity: cast of Cr/Ni 1311 bteel.

Components in the regions of lower velocity: Cast iron, Ni, Mo-alloyed. Gate vanes: Forged Cr/Ni

13/4 stcel:

protective

laycr on thc gate vane channel wall of<:r/Ni by built up welding. Spiral casing8

linc gr;~in stcel, welded from platcs

of

3600 bar yicld point. Stay ring: CrjNi

171.1

cast steel; stay vane

surlilce: metal spray layer of Ni-AI-13 Cr steel. Through shaft

2

lined with hard chromium layer,

ncccssriry to decouplc turbine duricg punlping by means of a special self shifting synchronizing

ovcrriding clutch, type

SSS.

Because of the pump, minimum subrnergcnce about 70 m. Tailrace

tunncl

1.5

km

long with 2-chamber surge tank. Maximu~n working pressure-90 bar. Fly-whecl

mo:ncnt so that start up time

T,

=

7,8

s. Rclativc overspeed after load rejection 50%. Fron special

ixsue. Scliluchsecwerk

3,4

bearings,

5

covers,

6

gate,

7

gate ring,

9

draft tube,

10

sh:~ft seal,

11

clutch

adjustmcnt. (Drawing courtesy

Sulzer Eschcr Wyss, Switzer.land.)

be

kept

in

limits.

Therefore the initial curvature of the bucket cross section close to the

inlet

edge should

be

as small as

possible.

In a limiting design, in consequence of stress concentration and wear near the cutting edge of a

bucket, the unit outplit per bucket can be increased only by blunting the edge at the cost of efficiency.

.Modern trends in the design of PTs are given in

(10.621.

Recent designs

arc

shown

in

the

Figs. 10.3.13 to

15.

Fig. 10.3.13. a) Wheel pit of the Pelton turbines of Sy Sima plant. Norway.

5

nozzle vertical

PT

in

operation since spring 195

1

and since that time the world's most powerful Pelton turbine.

H

=

885

In:

rt

=

3110 rprn;

P,

=

315 MW;

e,

=

350

MW,

built by Kvaerner I3rugg

A/S,

Oslo.

Nor\vay. b) From thc same manufacturcl-,

2

Pelton turbines

of

thc

Lang

Sima plant under erection,

in

operation since 1980. They are vertical 5-nozzle units with

I],,

=

1

151

m;

rl

-

428

rpm;

W

(rated value

H,

=

1006

m.

=

260

MW).

In

this plant, at highest head the

11

.

If

.

P

of Sy Sima

plant,

and

175%)

that

of

Wehr. Note thc bridge

of

jct

deflector, bucket

cut-out, Vuckct

edge,

and stiffening ribs on the back of bucket. (Photograph courtcsy Kwaernc-r

Brugg

S/+,

Oslo, Norway.)

Fig.

10.3.14.

Elevation

of

5

jet vertical

PT

L'Eau

d'Olle, France (Owner

EdF).

Plant

is

the

upper

stage

o

the barrage Grand'Maison,

an

earth-fill gravity

dam,

crest

height

140

m.

width

550

m.

live

stora~

vole

1

a--.....

-

- --

.

.-

-

..I-

rr

O~T

+

n??

4-A

Fig.

10.3.1 5. a) Cross section through one of the

5

horizontal shaft sets with ?-wheel. 2-nozzle

PT

,I

prutz, Knunertnl, Austria (o\vner Tiroler Wasserkraftwerkc, Innsbruck) built by

J.

XI.

I*i)it/i.

H

=

890 m, n

=

500 rpm,

P

=

7S,8

MW.

Sm;ill dcflcction ariglc of y-fitting and small curv:iturc of

the

pipe at the ends of the y-bra~iches diminish disturbances of uniformity in thc flow admission to

~hc

nozzles (so called "tongs design"). Whccl of intcgr;~lly cast stair~less stcel,

D

=

2,31

m,

nccctlc

servo motor in the nozzle pipe with fcedback linkage of both the nozzles joined together. Ivhich givss

acertain position of the jet deflector via a carn to a given ncedle position. Both

jet

deflectors operated

\:ia linkage by

a

common servo nio!or. Smnll brake nozzlc between the

2

main noz~les. jet splittcr

on

the

top of lo\icr nozzle to minimizc jet disturbnncc from the other jct. C.ising cquippcd I\-ith guicic

plates to deflcct jct towards the tailwatcr in the case of runaway. Occasi~nally Dndly snndcroded by

fatigue-conditior~cd failure of the surgc tank lining. (Drawing courtcsy

J.

I!!.

I'birh.)

-

-.

.

-

--

-

..

-

--

-

--

.

Fig. 10.3.1 5.

b)

Cross section of I-wheel, I-jet horizontnl shaft

PT

Salanfe Mii\.illc. S\vitzerlai;d built

by

Vcvey-Charniilles

Engineering

Works, Switzcrlnnd. Straight admission pipe, necdlc scrvoniotor

in the nozz e pipe, jet prcsser, brake no7.zlc. Because of thc high l~ead, sm;lll jct tvhccl diametcr ratio.

H

=

1447

,

rr

=

500

rpm,

P

=

35,2

MW.

This is the 3 rd higl~cst hcnd of the tvorlri iisecl

by

tr

PT.

i

PTs

ith the highest !,cads in the world, n;llncly Chandolinc. Grancie Discncc. Switzcrlanti

(H

=

1710

/n,

I'

=

36.6

M

W)

and Reisscck, Austria

(ti

=

1765 m.

P

=

22,8

h,W)

arc also

of

the

I

nobzlc type and wcrc built also by Vcvcy Charniillcs Enginwring \+'orks. S\vitzcrland.

(Dri1wing cdllrtcsy Vcvcy Charmillcs Engineering Works.)

10.3..3.

'l'lle

litnits

of

a

F7'

in

the

lower

Ilcad

range

Accorrling to the expcricncc of Sul~cr 1scllt.r Wyss, tI1c1-c exists also

a

Lone

of over]

%%&

OP

;;1

with thc K;lpl;ln tt~rbinc

(KT).

This r:lni.,e has npprorini:ltsly :tn llppr limit

:lt

a

head

of

ahout 70

rn.

Son~e

KT

l)l:~nts

with

:111

upper he;ld limi! :~bovc this figlire are usually

locatcd

at

tile

base of a dani storing their tailwatcr and

needing

no

esscnti:~l

excavation

'

3

for su bniergence.

f

In th'e range of low flows between

1.5

and

2.2

m3/s

up to

n

Itcad of 23

in,

the upper head

*

limit

IE(m)

of this zone rcads (Fig 10.3.16):

111

H

=

1.33

t

2.42

111

Q,

Q

in rn3/s. In the head

:

'-34

range between

23

m

to 67

m

and the flow range between

2,2

m3/s to 13 mJ/s this litnit is

%

given by:

Irl

H

=

2,55

+

0,672

In

Q.

b

2

In the head rarlge below

70

m

and

a

flow above 27 m3/s thc limit between

FT

and

KT

"

follows from

In

H

=

0,665

In

Q.

These formulas reflect only the actual state of the art. This changes

in

coilrse

of

time

so

-

as to raise the output and head limit for a

KT

in

thc

fiiturc. This holds especially for lower

flows between 13 to 350

rn3/s.

Tile

causes for this evolution may be traced to the following

reasons:

First the low-head

FT

with hig1:est specific speed has

a

strongly hook-forrnecl

q

(P)

graph

'

OWs

1

2

5

10

20

50

100 200

500.

1000

Fig.

10.3.16.

Range of applicdtion for

the

various hydro turbomachines on

a

Q(H)-graph according

to

Sulzer Escher Wyss.

Raabe J. Hydro power - the design, use, and function of hydromechanical, hydraulic, and electrical еquipment

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