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

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Fig.

10.2.1.

Elevation of the

at Schaffhausen, Rhine, Switzerland (oS#ncr: EW Schaffl~auscn,

Switzerland), design Sulzer Eschcr Wyss

9,3

71,4

rpm;

14,5

hlW.

Widely wcldcd

dcsign, thrust bearing easily accessible after dismantling and lifting the connecting ring between thc

shaft

and

the gencrator rotor. Facilitated by leading

off

the tliruqt via

tall truncated cone and head

cover into the stay vancs without strcssing the concrete of the pit. This principle of shortest flux of

force is also implcmentcd by propping

pairs of oppositely locatcd gate servomotors (only

couple

the

gate operating ring) on the head covcr. Only

guide bearings thus loads statically determined.

Small high pressure runner servomotor underneath the blades shifts the runner's centre of gravity

towards that of the adjaccnt bearing. Servomotor piston bolted on the hub facilitates oil admission

horn

an oilhead abovc the rotor. Generator rotor of umbrella design, with

ccntre of gravity in the

plane of upper guide bcaring.

stay vane;

guidc vane bottom ring elliptically curved (otherwise

f'all and increased scnsitivity to cavitation of the outer part of the runncr bladc);

guide shicld with

Inspection window for thc runner shaft scal and "stand still" seal to renlove or inspcct the shaft scal;

@ate scrvornotors;

runner servomotor;

thrust bearing;

alternator rotor;

jacking and brake

for

the rotating parts; 9 exciter;

scal. (Drawing courtesy Sulzer Eschcr Wyss)

Fig.

10.2.2.

Elevation of tbc

KT,

at Jupia, Kio Parani, Brazil (owner Centrais Elcctricas dc

Sgo

Paulo

CESP).

14 KTs built by Sulzcr Esciier Wyss, Switzerland and Hydroart, hliian, Italy under

CIE as main contractor.

24.4 m;

78,3 rpm;

103

MW.

To date the largest block of

power bililt

thc West. Runner: 1311 Chrornium!Nickel stainless steel blades;

8,4

axial

thrust

2300

tons. Thrust bearing with balancing hydraulic chamber (Hydroart) well accessible below

eleciric rotur iikz that in

iiig.

10.2.1.

oil head, oil admission

the runner servomotor by te!escopie

tubes;

thrusr bearing;

alternator stator support

%ria

stiff arniour platc on the stay vanes; 4 pairs

of gate

rinp servomotors on the

head

cover;

beil-shaped permanently

lubricated

lower guide

bearing;

shalt ssal;

runner servomotor with piston screwcd on t!ie hub. (Drawing courtesy

Hydroart, Milan, Italy)

Fig.

10.2.3. Elevation of high head

Pirttikoski, Finland. 2 sets built by Sulzer Escher Wyss.

27 m; n

115,4 rpm;

66,3

MW.

Runner

5,8

blades. Good accessibility of t!le

Important parts such as the pivot of the gates and thrust bearing.

shaf:;

hub: 3 runner blade:

hladc drivc; 5 servomotor cylinder as part of hub;

piston; 7 oil supply by telescopic tubes;

oil

bad

and runner blade fecd back; 10 lower throat ring;

upper throat ricg removablc to dismantle

runner; 12 insert

ring dismantablc with

11;

13 bottom gate ring;

draft tube stecl lining;

Ws;

head cover;

bushing of gate stem;

guide vane lever; 20 stay vane ring: 21 stay vane

with long tic rods to transmit its tension into the concrete;

water guide shield with a man hole

arthe seal; 23 lower guide bearing;

shaft seal; 25 leakage pump;

gate operating ring; 27 link;

pairs of gate

servomotors;

29 supporting tube; 30 connecting ring betwecn shaft and generator

to facilitate easy revision of the thrust bearing;

support ring; 32 pads;

support

the

Juide bcaring 35; 36 oil pan; 37 thrust bearing case; 38 spider for guidc bcaring;

brake rlnd jacking

kvicc

for thc alternator rotor; 40 alternator rotor; 41 alternator stator; 42 spider

exciter:

"titer; 44 pendulum

generator;

45 throttle bush;

outlet pipc; 47

leak

oil chamber;

pressure

'dieving bore;49 leak oil chamber; 50 emergency shut down pendulum; 51 oil circulation pump for

thrust bearing; 52 ditto for the governor. (Drawing courtesy Sulzer Eschcr Wyss)

I.,?.

lO.?.-!. I'~L-\:~[~OII

K.1-

rl,.lr.

11;

.iil

(I-\\

ncr: hlc~idcs

JIIIIiUr)

(~)~:sI~II

Xibrpic).

llL3~

Ill

i3.4

h1~.

osl

po\\

1'111

\L'cbtcrn

I(')'.

~i,,.,-

plificcl \\~.ltlccl <lcsigri. Tlirusl

bear-

ing

cI<?3c

[<)

flic lic;~CI COVCI.;

"Wer

gilitlc bc;lsi~is

CIOSC

tIlc

run-

ncr;

si~islc

5~1.1

olnotors

for

g:,tcs.

~0111

l~sy Ncyrpic,

Gscnoblc. I-ri~ncc)

Fig.

10.2.5.

Sectional

drawing of KT Lilla Edet, Gota AIV, Swedcn (owner, Swedish state po\\cr

board), ordcrzd

1922

and

built by

KaMcWa

AB,

Kristinehanl. S~cdcn, data:

6.5

66,7 rpm.

p,,,

MW,

runner diameter

5.8

The first Kaplan turbine in the world of

I;lrge

dimensions,

dcsigncd by

0101-

Englesson,

chief cngincer of KaMcWa and active there bct\\cen

1906

and

1953.

Contrary to

K;tplan's patent with a stationary runner scrvonlotor operating rhc

runner blades via

s~ationary rocking lcvcr with blocks which axially ~novcd a grooved ring arcund

11ic shaft, thc runr~cr servomotor was arranged in the hub. Well informed about prcvious fr?ilures on

thc European continent, the S~cdish engineers paid the greatest attention to the cavitarion

problem.

speci;~l test tunnel

was

built and put to work in

1924.

This was, according to Hansson

probably thc first cavitation test stand in the world for cavitation research at a turbinc manutac-

lurer's shop. Efficiency tests, carricd out in 1926 by

Duhl,

showed a bcp

efficiency

of 92.5%, an

cficiency above

90°/0

between

3,5

and

10,5

and above

82,7%

berwcen

2,s

and

14,3

hlW.

Flow

admission by a semi-spiral casing of reinforced concrete with a

cylindcr as core,

stay vancs.

gates with shc;~r pins against ovel.stressing, runner chamber cast iron, hub of cast steel and of

cylindrical shape,

blades of cast steel attached by a bronze coated bearing, screwed on the hub

body. Inside the bearing ring arc crank pins bolted to the blade with

block, sliding in a groove of

the cross head "nderneath thc piston. The

cil

pressure of 20 bar is si~pplied through a steel pipe in

the central bore of the shaft.

The

control valve is located inside the piston and actuated from the

combinator cam on the top of the generator by means of the oil pipc. Thc lowcr part of the hub is

filled with low

pressure

oil, which is brought to cirulate through all bearings including

the

b!ade

pivoting bearings by mcans of a piston pump and by the movcmcnt of thc blade mechanism. At thc

blade flanges there arc doublc acting seals of leather which

effectively

prevent oil from leaking out

and water from entering the hub. The relatively long lower guidc bcaring is

lubricated

with self

circulating oil. The shaft scal of thc labyrinth typc. The thrust bearing is placed on a spidcr l~bove

Ihe alternator stator. Its load is carricd by

segment pads

supported

on a grcat number of coil

The

average oil pressure on tlie bearing surthce corresponding to the maximun~ axial thrust,

&25

bill. There is an external pump circulating tlle lubricating oil. Thc draft tube is of the elbow

type

ova1

sections

in the ot~tlct of tlic bend. It is made of rcinforccd concretc with

plate lining in

'Is

upper

conical part. (Dritwing courtesy KaMcWa

AB,

Kristineharn, Swcden)

Fis.

!O.Z.j.

Sectional dr~\\ing of a

at Solber~foss, Norway (owner Oslo Lyswerkcr). commi-

sioncd

it1

!?SI. Dntn

78.9

rpm,

106.7

hIW.

Runiicr

8,3

tlollow thin

\\alli.d ne1dr.d shaft with an

outermost

dinrncter equal to that

the thrust bcaring collar on tts lower

end.

hence

ki\our,iblz

IOU

ratio of wctght to torstonal stifiness. Thriibt bearing directly supported

\\eldcd

11:,1d

covcr. r\dcqitatc curvatitre

the nriter dcflect111g sliicld creates

spacious head

coler

\\it11

good

access to tllc

IOHC~

gltidc bearing. 'Thc latrer is

bcil

sliaped

and

subtncrscd in the

oil

pan,

f:lcilitati~?g start up

\\ili~

liquid friction. Stay vane iie rods to tr~nsmit its tension into the

concrzte surrounding the spiral casing. Runner servoclotor

the hub above the blades with

nlo: ~blc piston aftcr Englcsson. (Drawing courtesy KaMeWa

AB,

Kristineham, Sheden)

10.2.6.

I~lc\latinn

I'orto Primavera,

Fig.

Brnzll

(I>csig~i Ncyrpic).

IS,3 ni;

69,~

rpri~;

103

Itunnor servomotor

istoll

scrc\ved

on thc hub. Runner

blade

with

~clac~~;lblC pivot. (Drawing courtesy Neyrpic,

C;renobl~, Fraiice)

The latter is facilitated by wide vertical and streamlined admission shaft and a highly

geared and thus small generator (Figs. 10.2

and 13 b) usually equipped with a plane-

tary gear. This design is limited in output because of the

gear (about 15

MW).

Because of the flow-conditioned limited external diameter

the bulb in relation

the

turbine runner and the increasing diameter of the generator

with decreasing head,

direct

coupling is preferred at heads above 10

In.

In West Germany at present, because of some

troubles with planetary gears, there is partially a tendency to restrict use of this gear in

favour of direct coupling even in plants with heads below

Because of its radially limited bulb, the bulb turbine, with the generator inside the bulb,

has

rather small fly-wheel mass. This is contrary to the requirements of stable rzgula-

tion.

this respect all designs of TTs with the generator outside the water duct are

superior. These are, e.g. the bulb turbine with bevel gear, the so-called S-turbine (see

below), and above all, the Straflo turbine.

special feature of adjustable conical or axial gates (usually found in TTs) is the fact that

the

tight closure usually required, restricts a vane design with twist, needed for the

generation of a constant moment of momentum vs radius before the runner.

Since

the gate operating ring turns about the sllaft and the gates about a stem on

cone,

Le lillks between gate lever and gate operating ring require spherical joints.

l..ic. IO.? 7. l'lcv;11in11

y,.

11.,~11

(i.11~.

I)~ll1lll~~.

l~,ll,,;,l,i3,

YIII

R,II~I;II~~~III.

S~IS

YII~OS~;,,,~~~

st:~tc

~o:\.cI.

bt::~rit).

(~)~~i~~

[dclii~~sr;~d

;\ICI;II

Works

l-hlz-

IJSSR)

scts built

~~~i~~

Ku~n;~nin.

11,~

35.4b

rn;

rpm;

17s

N(>\V

I;krg~st

OU~,,,,~

fur

ti.['

tile

nrorId. Rotor:

bliid~~:

1),5

rn.

Servo-

motor

houscc!

the

hub

,\hO,zC

the bl;lclc. drivc with pl~11~~~~

pnssins through

the

cy\indtr

covcr. Thrust bearing slip-

portctl

truncatctl

cone

hcaJ L'OVCI-:

TOWS

of lilted

pads

lnl-;lllt:l.

Start

the

pads rct;~i!lcd by slide

dogs

th?: wtur slightly

hy-

draulic;\lly lifrcd

the

gcn-

er;\tor brake tlicn usetl

jack.

Smooth opcr:ltion. but serious

cavitation pittin&

blni!~ tip

after n:cr.lo,~d. (I1r:lwing cour-

tesy

Rcsit:.~ Works,

Rumania)

Thr:

2ener:itor

ci.:~

outsiile thc lilnin llo~, eitllcr driven by

bcvel 3e:eilr

(Fig.

3.4.10)

shait passinn the draft tube double curved

(Fig.

3.4.27), (S-turbines).

These v:t!-{ants :\re lirnitcd to small turbines. Tlie type ~vii!l a shaft passill:: through the

clraft tube also f'lilciiitntes the syphon design

(Fig.

3.4.29)

favourable for

quick

ancl simple

sh:~t

down

the

set

aeration.

Altllough iilc S-turbine desien lias an additional loss due to its extra beild and the

disturbance

of thc flow

the rotatins shaft, its generator is more easily accessible.

areas n-i!h !ow rainfall, not requiring

power house, with its

protective

roof for the

senerator.

e~iables :he lowest specific investment cost of

plant

(51.1.

fig.

3.4.25).

Another rnri;lr~t is

the

rim generator turbins (Figs. 10.2.17 and 3.4.30). This was dcsi~ned

bet\veen

1936

r~nd 1953 in

about

70 nearly equal turbines of about

1,s

the

firm

Escher \\:);ss (now Suizer Eacher

Wyss),

after an initiative of

Fischer,

011

the West

Gsrmnn rivers Iller. Lech, Saalach.

Hc;~

tllc

rotor of

tiit'

nlterilntor shrank on the rim of the runner is effxtivcly water-cooled

il~ld possisses

\he

desired high fly-wlieel mass.

Fip.

10.2.17

shows

the

decisive seal on

the

frant hces of

the

shroud (rim), that reduces the leakage

some

lis

(in case of about

SU~III;~

diameter). bur onl! proof iigainst water with no sand suspension.

Ziirrr~rr

[10.25]

reported good opetiitin: experiences but also initial troubles wi:h those ninchines during

service.

Fig.

10.3.9.

Co~np;irison

the

works

~C~H'CCII

vcr[ic;~I

K;I~I;III

zonti~l

bulb

unit,

frv~il

Ct:rillon

[3.

civil

.ill-hinc

1231.

vert~cal

shaft

Kaplan

turbine

bulb

unit

Except for orie double yeguiated turbine shown in Fig. 10.2.17, this design was ~~\r?cic with

fixed runner vanes. Since the runner blade adjustment

needs

radial clearance of the

outer pivot of the vane,

u,hich

must transmit the torque, a quiet running rim needs at least

a radial support by

guide bearing. This is found in the Straflo turbine

110.22;

10.29 to

10.321.

any

the axial thrust of the runner has to be transmitted from the thrust bearing

support in the bulb via stay vanes into the surrounding concrete by long anchors (because

the

ad~nissible shear stress between iron and concrete is only 2 bar).

an outer radial

support of

tlie rim generator is required for runner vane adjustment, it is also possible to

trcnsmit the axial thrust originating from the runner vano (at least partiaily) through the

latier to an axial thrust bearing on the rim. Hence the hub and its stay vanes, now

disloaded from the torque and possibly pa1 tially from the axial thrust may be designed

slim and usefully streamlined to the flow.

This was also the main idea of the "Straflo"

design of Sulzcr Escher WysS. Here the radial

aad ever~tualIy also the axial bearing

the rim consists of a number of water-lubricated,

self-adjtlsting hydrosta?ic water heads (supporting sources), uniformly dis!ributect over

the circumference. These water heads serve simultaneously also, in connection with

labyrinths and rubber

Iloses,

to repulse sand from the working water

(if

existing). See

Figs. 10.2.18 and

19 [10.29 to 10.311.

Fig. 10.2.20 shows the self adjustment of such a supporting water head in the case of any

disturbance

tilting.

obtain the same tangential force from all the outer blade

trunnions, these are linked to the

altcrnator rotor by nearly tangential oriented plungers.

The load

the latter is equalized

interconnecting their oil cylinders, which are

attached

the alternator rotor.