Raabe J. Hydro power - the design, use, and function of hydromechanical, hydraulic, and electrical еquipment
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Fig. 3.4.4. Alternatives to spiral distributor of vertical multi-nozzle PTs a) Pine-tree-design, plant
El
Toro, Chile.
H
=
5-15 m;
11
=
333,3
rprn;
P
=
I
16,2
MM1.
b) Ramification of
2
branches in parallel,
plant Mauranger, Norway.
H
=
825 n~;
11
=
500 rpm;
P
=
126.8 MW. Note only
1
shut down valve
far
2
neighbouring sets (Drawing courtesy Vevey Charmilles Engineering Works).
Fig.
3.4.5. Cross section of
the underground power
house and valve chamber
at Nendaz,
Rhone, Switzer-
land.
Horizolital 2-whccl,
I
-no;r.zlr:
PT.
II
=
1001 m;
11
=
500 rpm;
P
=
6.64
MW. Space re-
quired per set 8250
m'
(Drawing Vevey Charmilles
Engineering Works).
In some rare cases
of
a hydropneumatizcd Pelton
T
with
a
wheel chamber submerged under a
~llanging tail water level (e.g. the occan by tides), the then pressurized tail water tunnel has
a
ceiling
that dcsccrlds in streamwise direction. This is made with the aim of separating and then returning
the air into the wheel chamber as much as possible by virtue of buoyancy. This is found in
the
N~rwcgi:ln plant Tysso, built hy Sulzer Escher Wyss (3.113; 3.1141.
97
Fig.
3.4.6.
a)
Cross
section of outdoor power house Sib. Austria (owner 'l'irolcr CVasserkr,lft\~crke.
Innsbruck). Two kcrtical, 6-nozzlc
Prs.
Power
house
of tall hall desien uith thc marti
crauc
i,i
ik
in!erior. Total
wight
of
the rotating parts of one
set
366
tons, tohl \\cifht of o:ic
sc'[
!022
ions.
11.
Cross
flow
turbines type Michell-Banki:
Preferably
in I'/Iicro Pour;.r pla~:ts (scc
Cap.
2.5).
To date mainly existir~g as the Ossberger design, mith
heads
below
100
m
and
using rivers with often strongly varying discharge and hence also largely varying tail
water level.
To use also the then varying elevation of the rotor above the
tail~vater level, the wheel
chamber of this
impillst: turbine is equipped with a draft tube accorci~ng
!o
Ossbergcr (see
Fig.
3.4.S).
By means of
a
"snifting valve" the wntcr level in
the
draft
i!~bt.
is
antom,~tically
kept at a distance from the \vheel so as to avoid immersion
of
the loner
ivllcel
edge
in
the water and hence to prevent disk friction. Now the jet passii~g the bladed ~\fhcel twice
underneath t!le shaft, expands against
n
pressure, that is bd:!ow ihat
oti
the
hi:
water
by
the draft tube water column
[3.115].
Thus the suction
head
of
illis
columr;
is
not lost.
Dividing
the
whecl
chamber
by
disks into seprate sections, into which
the
water is
tijmitted by differently adjusted guide vanes, the discharge may cliange
in
a
wide range
due to
op:imum
efficiency.
The dcsisn
is
noted far great sitnplic~ ty of construction (cylindrical runner vanes from
plates,
all
welded).
b)
Elevation of one set,
n
=
500 rpm,
H
=
1238,5
to
1257,5 nl, with 2 sets
P
=
233,3
10
244,3
MW,
with
1
set
P
=
259,9 to 264,8
MW
(in consequence of penstock loss, a smaller output with 2 sets
Operating) wheel,
D
=
2.85
m,
flow admission similar
Fig.
3.4.4.b.
PT
built by Sulzer Escher Wyss.
Fully
water cooled alternator. (Drawing courtesy Tiroler Wasserkrafiwerke, Innsbruck).
Fig.
3.4.7.
PT
needle drive inside nozzle. No external linkage. No reaction foroc on the pipe wall or
surrounding concrete. No disturbance of the needle control by rod elasticity.
2-stagc compcns~t;on
piston without a spring to equalize the adjusting forcc nlol~g the
ncedle
travel. Sulzcr
Esther
Wyss
desig~.
a
IIOZLIC
pipe
with guide fins. b nozzle; c jet deflector;
d
needle head detacl;ablt.; e necdle rod;
f
servon~otor cylinder;
g
piston;
h
oil head; i feed back;
k
re;icving piston
(Courtesy
Salzer Escher
Wyss).
Fig.
3.4.8.
Cross scction
berger design;
1
control
water level;
4
draft ttibe
West Germany).
of
a
Michell-Banki turbine of Oss-
vane;
2
silifting valve;
3
draft tube
(Courtesy
Ossberger Weissenburg,
Typical superstructures of the Ossberger turbinz are shown in the Figs. 3.4.9 and 10.
111. Reaction turbines. Here the following types are used: Ka~lan turbines (KT), tubular
turbines
(TT)
with their variant of bulb turbine
(BT)
and Straflo turbine
(Sl')
or turbine
with rim generator, Francis turbine
(FT),
diagonal turbine (DT) after
Derinz
and
Kvintkovsky
[3.116; 3.1 171. There the following typical designs of superstructure and
machinery may be distinguished.
a)
Wall turbine with horizontal shaft (in general
FT)
in
a
free surface chamber (see
Fig.
3.4.1
1
a), flow admission without spiral casing with inside regulation of gates. Over-
hung design of runner, elbow draft
tube traversing the head tank
[3.11Y;
3.1191.
Fig.
3.4.9.
Superstru~turc of largcr hl~ni power plant cqu~pped \v~[h li.111'~ l-O\\bcrgcr
t
111-~IIICZ.
Drouct, Haiti;
3
sets:
H
=
9,7
m;
n
=
120
rprn;
P
=
0,55
hlW;
2
sets:
H
=
I_'
I5
In;
rl
=
135 rprn;
P
=
0,69
MW.
Bclt-driven speed governor with control linkage; step up bpur gcar; high spccd
alternator (Photograph coilrtcsy Ossbcrgcr, Weissenbt~rg, \Vest Germany)
Fig. 3.4.10. External vicw of a high
head
Ossberger turbine. Totora-Epizana (Bolivia).
)I
=
150
m;
"
1500
rpm;
P
=
95
kW.
The size of governor and direct coupled generator in relation to the
lurbine casing reveals the power density of the "high hccld" crossflow turbine type Ossberger.
(Drawing courtesy Ossberger,
W.
Germany).
Fig.
3.4.1
1.
a) Francis wall-turbine with horizontal shaft b) Francis pit-turbine with vertical shaft.
Botn supplied by open head race tank. (Drawing courtesy Voith)
b)
Pit
turbines with vertical shaft (see Fig. 3.4.1
1
b), admission, regulation and runner as
a),
elbow draft tube in concrete, FT or
KT
[3.120; 3.1211.
a)
and
b):
Clleap
but bnd innow.
c)
Turbine with vertical shaft, runner as a), admission
by
semi-spiral casing in concrete
(see
Fig.
3.4.12)
with underground potver house (see Fig. 3.4.13) or open air power house
(see
Fig.
3.4.14), external gate regulation. Usually
KT.
ti)
Turbine with ce~ tical shaft, admission by spiral casing of concrete, steel-lined, riveted
or welded and
embedded
in
reinforced concrete or made of cast iron. For high head
KT,
FT or DT (see 1-igs. 3.4.15 to 3.4.16).
e)
Turbine wit11 horizontal shaft, adrnissior! by spiral casing of cast iron or steel, welded
ol-
riveted. For
high
head
KT
or
FT
of wide head range (see Figs. 3.4.17; 18).
f)
TT
with rim generator, horizc~ntal or slightly inclined shaft, traversing the power house
of
a
submersible plant (see Fig. 3.3.3), recently as the Straflo turbine
(ST).
In the original
version with an axial distributor and normally fixed runner vanes (see Fig.
3.4.19).
In
the
Fig.
3.4.i2.
Plan of semi-spiral casing and elbow draft tube of vertical shaft KT. Plane joint
of
neighbouring concrcte blocks. Excentric
flow
admission in spiral
compensated
by
curved draft tube
centre line. Tongue about
30"
upstream
of
turbine axis. Before tocgue generation of cirulation only
by stay vanes
a.
(From Voith)
~ig.
3.4.13.
High hcrld
KT
pirttikoski,
Finland
in
un-
derground
power house
(A
scandinavian ftat~~rc).
H
=
27
m;
n
=
115,4
rpm;
P
=
2
.66
M
W.
KTs
built
by
Sulzcr Escher Wyss. Stop
logs
in
draft tube. Higher
head stresses stay vanes by
tension, which is transmitted
into concrete by tie rods.
1
maximum,
2
rnininiuln tail-
race level
(Drawing
courtesy
Sulzer Esclier Wyss).
ST
version mainly with adjustable runner vanes and a conical distributor, also useful for
tidal power (see Fig.
3.4.20) [3.122].
g)
BT with ahernator in a bulb upstream of the runner and directly coupled to it. double
regulated. To mount the generator rotor, diameter
D,,
the following possibilities exist:
1) The bulb in an open flume accessible by
a
portal crane, a possibility for river and tidal
plants in
t!le open air (see Fig. 3.4.21). Generator easily accessible, rarely found.
2)
The bulb with a hatch
on
its top for the generator rotor (Fig. 10.2.1
1).
Expensive but
easy access to the generator.
3)
The bulb with access through a bore from the side of the runner, diameter
D
>
D,,
(regular case). Then only one hatch, accessible by the main crane, is required for the
runner and the generator rotor (Fig. 3.4.22)
[3.123], generator badly accessible.
The design
2)
and 3) result in
2
guide bearings for an output
P
<
40
M
W
(Fig. 3.4.23),
and
in
3
guide bearings for
an
output up to 60 n/lW (Fig. 10.2.10). Both the last types
2)
and
3)
can also be used in tidal power plants (Fig. 3.4.24).
h)
BT, usually double regulated and with conical distributor, alternator with high ratio
planetary gear, the shaft horizontal or inclined. The alternator
rnay be dismantled and
assembled or access obtained to it through a hollow stream-lined access shaft to the bulb;
the draft tube crosses the power house, split into pieces, hence the runner is accessible and
may be dismantled by
rr
crane within or outside the power house, for river power plants
(see
Fig. 3.4.25) and for tidal power plants (see Fig. 3.4.26), cspecinlly suitable for the
Fig.
3.3.14.
a)
Lateral section of adjacent blocks of vertical KTs, Feldkirchen, West German-
Austrian Inn. (German owner Innkraftwerke
.4G, Toging)
H
=
9
m:
n
=
90,9
rpm;
P
=
3
-
38
M
W;
KT
Dvilt by Voith. Asymmetric draft tube for plane joirit of ncighbouring
sets.
b) Longitudinal
section. Outdoor pit power house. Main crane outdoors,
lrlso for stoplogs. Trash rack rake. Access
door
ta draft tube from spiral. Supporting pillar in the dralt tube past the bend. Once stoplogs
inserted,
the
drainage of the spiral into
the
draft tube and then into the sump of the drainage pumps.
(Drawing courtesy Voith)
lowest head range and output
up
to
15
MW,
according to the abilities of the gear
"
manufacturers
[3.124].
i)
TT.
single or double regulated, with
a
horizontal or inclined shaft crossing the draft
tube bend, the generator directly coupled or gear
-
driven in
the
power
house (Fig.
3.4.271,
or, as the cheapest variant, in tlie open air (see Fig.
3.4.28),
so called S-turbine. This type
Fig.
3.4.1
5.
Longitudinal section of power house and set, Rosshaupten, Lech, West Germany (owner
Rayerische Wasserkraft AG
BAWAG,
Miinchen). Vertical
KT
with its spiral casing in concrete,
steel-lined. At inlet
a
butterfly valve and y-fitting.
H,
=
40 m;
n
=
200
rpm;
P
=
2
-
24
M
W.
Runner
7
blades. (Drawing courtesy Voith)
of
machine may also have a vertical shaft, passing a bend or an open flume before the
runner inlet. The bend in the draft tube reduces the efficiency.
j)
TT,
11oll adjustable, with inclined shafi and draft tube bend as a siphon for convenient
shut
down and a head below
3
m,
also useful as a free stream turbine to diffuse the kinetic
energy of river rapids (see Fig. 3.4.29). For small units.
k)
TT
with a horizonla1 shaft of the
BT
design, the generator outside and driven by
a
bevel gear and a shaft passing through a hollow stay vane (see Fig. 3.4.30) (gear limits
Output).
1)
K'I'
with a vertical shaft, admission by a semi-spiral chamber of siphon design, the
generator directly coupled, or with spur gear (see Fig. 3-4-31), or bevel gear. (Output limit
gear-condi tioned.)
ln)
Turbine with conical distributor as a diagonal turbine after Deriaz
(Fig.
3.4.32), a
vertical shaft
KT
(Fig. 3.4.33), or a tubular turbine of different design
(BT,
Straflo,
S-turbine).
Fig. 3.4.16. Seciional view of vertical
FT
Cabora Rassa, Zambesi, Mozambique, Africa (owner State
power board of Mozambique).
H
-
1
13,5
m,
11
=
107
rpm:
P
=
5
.4!5
MW.
One of the most power-
ful
FT
sets ever built in Western Europe
by
the collaboration of Neyrpic, Grenoble, France
and
Voith, Heidenheim, West Germany. Parallel plate stay ring with guide rolls. Hcnce reduced outer-
most diameter
of
the spiral casing. Concrete around the spiral reinforced in the meridian between
the stay rings (Drawing courtesy Voith).