Warnick C.C. Hydropower engineering

Подождите немного. Документ загружается.

Pressure Control and Speed Regulation

Chap.

seed settin;

Wlcket gates

Relay valve Servomotor

Figure 10.1

Schematic drawing of isochronous governor

The sequence of governor operation consists of the action of the flyballs,

which respond to the speed change and transmit motion through the system of

floating levers to the pilot valve. The pilot valve equipped with relay valves causes

oil pressure to be transmitted to one side or the other of the servomotor. The

action of the piston of the servomotor in turn opens or closes the turbine wicket

gates and regulates the flow of water to change the speed.

The .speed of a turbine will deviate from normal

syncllronous speed for

certain percentage of load change. The amount of deviation of speed will depend

on (1) the time required to alter the flow of the hydraulic oil in the governor

system to correspond with action necessitated by the change in load,

(2)

the

amount of flywheel effect of the entire rotating mass of the turbine and generator,

and

(3)

the time required for the water flow to respond to action caused by the

change in the turbine operating point.

The simple governor and control system is shown in Fig. 10.16. The system

silown in Fig. 10.16 is known as an

isochrot~ous governor.

The isochronous governor

is inherently unstable, and although

some stabilization results from the characteris-

tics of the turbine and connected load, these are generally inadequate and an addi-

tional means of stabilization is required to overcome the unstabilizing effect of the

inertia of the water flow in the penstock. The necessary stability is provided by

feedback from the servomotor, which, by means of the

dashpot, temporarily

restores the control valve toward the null position, and thus dampens the servo-

motor movements. The

dashpot functions with a spring-loaded valve that is me-

chanically linked to the servomotor and to the controls from

the pilot valve and the

flyball mechanism.

diagram'of the operation of a dashpot governor is shown in

Fig. 10.17.

Speed Sensing

To control the turbine speed, the governor must sense the system speed and

compare it to a standard. In the case of a mechanical governor, the flyball mecha-

nisn~ is driven by a permanent magnet generator (PMG) attached to the generator

shaft, or by a potential transformer

(PT) so that any change in system speed results

in a change in

the flywheel mechanism's pcsition. In an electronic governor, the

line frequency may be sensed directly from a potential transformer or the output

Speed Control and Governors

Speed setting

Flyballs

Needle valve

I-

Pressure tank

Dashpot

Pilot valve

wicket

gates

Figure

10.17 Schematic drawing of dashpot governor.

frequency of a speed signal generator (SSG) attached to the generator. The output

frequency is compared to a standard and the difference is processed electronically

to drive a transducer-operator control valve.

Power

Unit

The power unit to operate the speed control is supplied by the oil pressure

system, which consists of a sump, oil pumps, accumulator tank or tanks, and an

air compressor. Oil is pumped from the

sump into an air-over-oil accumulator

tank(s) as needed to maintain the required pressure (see Fig. 10.17). The accumula-

tor tanks store the oil until needed in the control system. Pressure in the tank is

maintained by the air compressor which admits air to maintain the oil at the

required level.

There are many auxiliary controls which are normally a part of the modern

governor. Two of these which are necessary for proper operation are the speed level

and the gate limit controls.

Speed level.

The speed level allows for manually adjusting the governor

control speed

from the norn~al seiting. This adjustment is usually limited to

t10

to -15% and serves to load the unit. If the speed control is set below the line

190

Pressure Control

and

Speed

Regulation

Chap.

frequency, thc unit will tlrop load. If set above the line frequency, tlie unit will

pick up load.

Gate limit.

The gate

limit control allows for manually setting the niaxirnum

gate opening that the governor will allow. With the gate liniit set at any intermediate

value, and the speed adjustment at a positive setting, the gates will remain at tlie set

point. The turbine is then operating at what is known as

blocked load.

Speed Droop

two or more generating units are operating to govern a system, it is impos-

sible for

them to maintain exactly the same speed. The governor with the higher

speed will try to bring the system up to its speed, and take

on load until it either

achieves this or the turbine reaches full-gate position. If it is able to raise the system

frequency, the other governor will sense too

high

speed and begin to drop load.

The governors will therefore oppose each other. To avoid this situation,

governon

are built with a feature called

speed

droop.

Speed droop reduces the governor

sensing speed as the gate opening or load increases. It is defined as the difference

speed in percent permitted when tlie units are operating between zero gate opening

and 100% gate opening.

The action of speed adjustment and speed droop may best be visualized by

referring to Fie. 10.18. If the specd adjustment is set at 5% and the speed droop at

and 100% gate opening.

The action of speed adjustment and speed droop may best be visualized by

referring to Fig. 10.18. If the specd adjustment is set at 5% and the speed droop at

1076, the governor sensing speed is represented by line

AC.

Points to the left of

108

105

Line

100.

0 50 60 100

Load

Figure 10.18

Spccd adjustn~ent and specd droop sclicniatic

diagram.

Speed Control and Governors

191

point

are seen as an underspeed condition requiring an increase in turbine output,

and those to the right are seen as an overspeed requiring

decrease in output. At

point

the turbine is operating at 50% load. If the system deviates to

999

normal speed, the turbine output will increase 10 percentage points to 60% load.

Any change

the speed adjustment shifts the governor sensirlg speed without

changing its slope (see Fig.

10.15).

Raising tlie speed adjustment three percentage

points from 105 to 108% shifts the turbine operating point to

an output increase

30%.

With several units supplying the load, all set with a significant speed droop,

the

system frequency would vary greatly with load changes. It is normal therefore

set one unit with zero or very small speed droop. Tllis unit would then

effec-

tively govern the system.

the load change exceeds the capacity of

the

unit wit11 a

zero speed droop setting, other units would pick up or drop load

ill response to

their settings. In a large system, units may be operated with blocked

load. and with

speed droop, and one unit with zero speed droop for governing the system.

The

governing unit (with zero droop) should be of sufficient capacity to Iinndle the

expected load variations.

To explain the speed droop concepts, the following example is

preserlted.

Example

10.3

Given:

power plant containing four

25-MW

turbine generators is supplying

load

80MW. Three units are operating at three-fourths of capacity and nre

Let

with

a,-ra,.&:%!a

..---A

A--

7p of 10% and a speed adjustment of plus

7.5%.

Unit

1s operat-

Given:

power plant containing four

25-MW

turbine generators is supplying

load

80MW. Three units are operating at three-fourths of capacity and nre

Let

with

effective speed droop of 10% and a speed adjustment of plus

7.5%.

Unit

1s operat-

ing at zero droop and zero speed adjustment and is carrying the

remaining

load.

The

system load increases to 85

MW.

Speed droop characteristics for the three unlts is

shown in Fig. 10.1

d zero speed adjustment and is carrying the remaining load.

The

:s to 85

MW.

Speed droop characteristics for the three units is

Load

Figure 10.19 Speed

adjus:ment and spced droop

for

I<xnnlple

10.3.

Load

Figure 10.19 Speed

adjus:ment and spced droop

for

I<xnnlple

10.3.

192

Pressure Control and Speed Regulation Chap.

Required: Determine the change in the system frequency.

Analysis and solution:

The initial load on units

0.75

18.75 MW.

The initial load on unit

3(18.75)

23.75 MW.

increase of 5 MW cannot

be taken by unit

23.75

28.75

25. The final load on units 1 to

MW.

The percent load on units 1 to

With a 10% speed droop, the load

change for units

is from 75% to 80%,

resulting in a 0.5% speed decrease (see Fig. 10.1

9).

0.5%

change ANSWER

100

0.5

99.5% speed

System Governing

For proper frequency control the setting of the governor must conform to

electrical grid

system requirements. In an isolated system, with one generating unit,

dlop

speed would be inappropriate, as the system frequency would vary greatly

with luad changes. In this case the speed droop and the speed adjustment should be

set at zero to maintain the proper speed and line frequency.

Equipment is available for sharing the load between several units. This is

called

joint control and allovis

all

the units in a power plant to govern the system

(with zero speed droop) by electronically controlling the governors to share the

load equally.

it is necessary to maintain close average frequency over significant

time periods fur electric clocks, a system must include equipment to integrate the

nunlber of cycles and signal a correction for any deviation from the frequency-

time value.

Governor Theory and the Flywheel Effect

The basic mechanics of turbine speed change caused by change

load

recognizes that the work done in the closing operation must equal the change

kinetic energy of the rotating masses, which is given by the following equation:

where

efficiency of turbine

input of turbine, Ib-ft/sec or kg-m/sec

Speed Control and Governors

193

power demand of system, including generator losses, Ib-ft/sec or kg-m/

sec

elemental unit of time, sec

WR~/~

moment of inertia of the rotating mass, lb-ft sec2 or kg-m

sec2

weight of rotating mass, Ib or kg

radius of gyration of the rotating mass, ft or

acceleration of gravity

32.2

ft/sec2 or 9.81 m/sec2

initial speed of turbine before load change, rad/sec

highest (or lowest) speed due to the load change, rad/sec

=time during change of speed or time of closing or opening of turbine

gates,

sec.

Note that

where

APo

magnitude of change of load in the speed change, lb-ft/sec or kg-m/sec.

steady state when output from the turbine equals the generator load,

q,P,

and awlat

0. When turbine output is smaller than the demand load on the

generator,

qtPl

and awlat

0, and the turbine speed decreases. When the

turbine output is greater than the demand load on the generator,

qlPt

and

awlat

0 and the turbine speed increases.

It is

commori practice to use a term,

called the flywheel constant, which is

given by Jaeger (1970) as

Some authors define the flywheel constant as

where

power output, hp.

Jaeger (1970) simplifies Eq. (10.51) to the following forms:

)

for load rejection

(10.55)

nSI_

1--k-T 1790

APo

for load increase (10.56)

Jaeger points out that the

depends on pressure rise and pressure change resulting

from water

hammer action. For rejection of load when the time of.speed change

is smaller than thc pressure pipe period

2L/a,

Pressure Control and Speed

Regulation

Chap.

and for time of closure or speed change where

2L/a,

where

penstock lengths, ft

water velocity in pipelinc;ft/sec or m/sec

velocity of pressure wave, ft/sec or m/sec

steady-state head, ft or m.

The flywheel effect can be related to accelerating time,

Tm,

for the rotating

masses of the turbine by the following formula:

where

is in kg-m/sec. The

U.S.

Department of the Interior (1976) gives the

fly.

wheel effect equation in the following form:

where

is in pounds,

is in feet,

rpm, and

Php

is in hp. In metric form the

equation is

where

is in kg,

is in meters,

is in rpm, and

PkW

is in

kW.

For

the purpose of preliminary planning it is important to define two other

terms. The first is

Tw,

the starting time of water column related to the water ham-

mer action, which is given by the formula

where

T,,,

starting time of water column, in seconds, and other terms are as de-

fined for Eq. (10.58). The second parameter of time is

Tg,

the equivalent servo-

mot01 opening or closing time. Hadley (1970) has shown that these terms can be

related to each other and to pressure rise in the turbine water passage

a curvi-

linear relation. The ratio

TWITg

is a function of pressure rise or pressure decrease.

This relationship is shown in Fig. 10.20.

For practical use

Hadley (1 970) has shown that a simplification can be made

Eq.

(10.55) and written in terms

and

as follows:

Speed Control and Governors

195

Figure

10.20

Variation in pressure rise

and pressure drop with servomotor

opening and closing time.

SOURCE:

Hadley

70).

where

is a coefficient that is related to turbine characteristics and has been empir-

ically expressed by

Hadley as a function of the specific speed, as indicated in Table

10.2.

For

normal speed-sensitive governing.the flywheel effect required has been

estimated by

Hadley (1970) to have the following relationship between

T,,,

mini-

TABLE

10.2

Variation of the Governor Coefficient

with Specific Speed

n,,specific speed

20 35

100

125

150

175 200

N,,specificspeed

76.3 133.6 190.8

286.3 381.7

477.1 572.5 671.8

763.4

(metric)

Speed Control

and

Governors

Pressure Control

and

Speed Regulation

Chap.

mum starting time for the rotating of the turbine units, and

T,,

the starting time

the water column.

Pelton turbines

T,,,

2.5TW

Francis turbines with pressure relief valve

Francis and Kaplan turbines

3.0Tw

Hadley also gives a rule of thumb for estimating the starting time or accelerating

time of the rotating

mass

follows:

Empirically, the experience record of units furnished to the

U.S.

Bureau of Recla-

mation reported by the

U.S.

Department of the Interior (1976) indicates that

FVR~

can be estimated by the following formulas:

Turbine

l~~l

23,8OO($Si4 ib-ft system (10.65)

24,213(2)514

.3/2

kg-m system (10.66)

~VA

514

Nomlal generator

WR~

356,000(~) Ib-ft system (10.67)

kg-m system (10.68)

The flywheel effect is a stabilizing influence on the turbine speed and speed

change. Most of the flywheel effect for direct-connected turbine-generator units is

in the rotor of the generator. In practice,

the flywheel effect is tlic design responsi-

bility of the generator manufacturer guided by the governor design and

the turbine

design. It is possible for the generator manufacturer to add mass to the generator

rotor to help in providing better speed control.

Governor design is

heyond the scope of this book. However, Jaeger (1970)

provides an excellent explanation of the basic mechanics,

matllelnatics, and move-

ment requirements. Another excellent reference on tile topic of speed control

and

governon is a training manual of the

U.S.

Department of the Interior (1975).

Details on

the

requirements and design for the servomotor and oil pressure require-

nlents are given in Kovalev (1965). To understand the usefulness of the various

relationships presented

011

specd control of turbines, the following example prob-

lem is presented.

Example

10.4

Given:

hydropower development is to have a design output,

2680 hp, at an

estimated efficiency of

0.91, a design head of

36 ft, and a synchronous

speed

257 rpm. The penstock sewing the unit is 600 ft long and has a cross

section of

A,,

50 ft2.

Required:

(a) Determine the minimum starting time T, for accelerating the rotating

mass to a stable condition and the minimum flywheel effect

wR2 to give

stable governing conditions.

(b) If the design closing time,

Tg, for the servomechanism is 30 sec, estimate

the expected pressure rise and

the accelerating time Tm for accommodat-

ing the expected pressure rise when a speed rise of 10% for full-load

rejection is considered. What will be the corresponding minimum fly-

wheel effect to accommodate the 10% speed rise?

Analysis and solution:

(a) First the design discharge must be determined in order to calculate the

starting time

T,. Utilizing the fundamental power equation, Eq. (3.8),

Velocity in the penstock:

721.06

=-=--

14.42 ft/sec

Using

Eq.

0.62), solve for T,

600(14.42)

=-=

7.46 sec

gHo (32.3)(36)

Find the minimurn starting time for stable governing using the relation indicated

Hadley (1970), Tm

3.0Tw, so that

(3.0)(7.46)

22.38

sec

ANSWER

Thc

required minimum WR2 is obtained from Eq. (10.60):

Transposing gives

(1.6

1O6)p0T,,,

(1.6

1 06)(2680)(22.38)

WR~

(25712

Pressure Control and Speed Regulation

Chap.

h'~2

1.453

106 lb-ft2

ANSWER

(b) It is necessary to characterize the turbine and find specific speed

11,.

Using Eq. (4.17) gives us

To keep the relative speed

change

Anln

less than 0.10,

Eq.

(1 0.63) will apply.

From Table 10.2 for

150.9, Kz0.66. For Tg=30,

TWITg

7.46130

0.25,

and using Fig. 10.20 for

TWITg

0.25,

0.27.-Then

135 sec

ANSWER

Using Eq.

(1 0.62) again, we obtain

1.6

IO~P,T,,

(1.6

10~)(2680)(135)

WR~

(25712 (257)'

8.76

lo6

lb-ff2

ANSWER

REFERENCES

Allievi,

L.,

"Theory of Water Hammer,"

Halmes, trans.,

Proceedings, Atnerican

Society of

mechanical

Engineers,

1925.

Araki,

M.,

and

Kuwabara, "Analysis of Pump-Turbine System Including Pipe-

lines,"

Hifachi Review,

Vol. 24, No. 5, 1975.

Hadley,

B.,

"Governing of Water Turbines." Chapter V in

Hydro-electric Practice,

Vol. 2, 2d ed., G. Brown, ed. London: Blackie

Son Ltd., 1970.

Jacobson,

S., "Charts for Analysis of Surge Tanks in Turbines and Pump Installa-

tions,"

Report No.

104.

Denver, Colo.: U.S. Department of the Interior, Bureau

of Reclamation, 1952.

Jaeger,

C.,

"Governing of Water Turbines." Appendix 1 in

Hydro-electric Practice,

Vol. 2, 2d ed., G. Brown, ed. London: Blackie

Son Ltd., 1970.

Jordan, V., "Reverse Water Hammer in Turbine Draft Tubes,"

Water Power and

Darn Consfrttcfion,

Vol. 27, Nos. 2 and 3, 1975.

Joukovsky,

N.,

"Water Hammer,"

Simin, trans.,

Proceedings, American Water

IVorks Association,

Vol. 24, 1904.

Kerr.

L.,

and

Strowger, "Rksumk of Theory of Water Hammer in Simple

Conduits." In

Syrnposiutn on Water Han1tt:er.

New York: American Society of

Mechanical Engineers, 1933.

:hap.

Problems 199

:ovalev,

N.,

Hydrottlrbines-Design and Construction,

1961,

Segal, trans.

Jerusalem: Israel Program for Scientific Translation Ltd., 1965.

dcNown,

S., "Surges and Water Hammer." In

Engineering Hydraulics,

11. Rouse,

ed. New York: John

Wiley

Sons, Inc., 1950.

dosonyi,

E.,

and

H, B.

S. Seth, "The Surge Tank-A Device for Controlling Water

Hammer,"

Water Power and Datn Construction.

Vol. 27, Nos. 2 and

1975.

Ilechleba,

M.,

tlydraulic Turbines-Their Design and Equiptnent.

Prague: Artia/

London: Constable

Con~pany Ltd., 1957.

qemet,

A.,

"Mathematical Models of Hydraulic Plants,"

Escher 149~~s Ne\c.s,

No. 1,

1974.

'armakian,

J.,

Waterhammer Analysis.

Englewood Cliffs, N.J.: Prentice-Hall, Inc.,

1955.

Juick,

S., "Comparison and Limitation of Various Water Hammer Theories,"

Mechanical Engineering,

ASME, Vol. 49, No. 5a, 1927.

itreeter, V.

L.,

and E.

Wylie,

Fluid Mechanics,

7th ed. New York: McGraw-Hill

Book Company, 1979.

J.S. Army Corps of Engineers, "Water Hammer and Mass Oscillation

Sirrlulation

Program,"

Users Manual

CEG

002.

Washington, D.C.: Office of Chicf of

Engi-

neers, n.d.

J.S. Department of the Interior, "Welded Steel Penstocks,"

Er~pit~eerir~g il.lor~o-

graph No.

Denver, Colo.: U.S. Department of the Interior, Bureau of Reclama-

tion, 1967.

J.S.

Department

the Interior, "Training Course for Power Operating Personnel,

Lesson

111, Governors for Hydraulic Turbines." Denver, Colo.: U.S. Department

the Interior, Bureau of Reclamation, 1975.

J.S. Department

the Interior, "Selecting Hydraulic Reaction Turbines,"

Water

Resource Technical Publication,

Engineering Monograph No.

20.

Denver, Coio.:

U.S. Department of the Interior, Bureau of Reclamation. 1976.

'ROBLEMS

10.1.

turbine installation has a normal design head of 50 ft, a velocity in the pen-

stock of 6

ftlsec, and a length of penstock from closure valvc to an open

water surface of 500 ft. Assume that the pressure wave velocity,

is 3000

ftl

sec. Determine the relative preskre rise if closure is less than 0.1 scc. What is

the critical time of pressure wave travel? If the time of closure

sec. what

will be the expected pressure rise and pressure drop?

10.2.

Visit a hydropower plant and determine the method of controlling water

hammer. Report on closure time of closing vaives or gates.

0.3.

simplified problem for a hydro plant involves a penstock of length 2500 ft,

the velocity of the penstock is 6

ftlsec, the penstock area is 100 ft2, the surge

tank area is proposed to be 2000 ft2, and the friction hcad loss in the pen-

stock

ft. Determine the approximate maximum pressure surgc

the

surge tank and time from beginning of flow until

maxiniurn surge if the gate

valve is suddenly closed.

200

Pressure Control and Speed Regulation Chap.

10.4.

Three turbine generators of

MW capacity are supplying a load of

and the load suddenly increases to

MW. Two of thc units are set with

speed droop of

and speed adjustment of

6%.

The third unit is operating

at zero speed droop and zero speed adjustment. Determine the change in

system frequency due to the sudden load change. What will the speed change

he if the load increases to

MW?

10.5.

For a small hydropower plant with a proposed servomotor opening time for

the

gates of not to exceed 12 sec, select a suitable penstock diameter if the

penstock is

1000

ft long and the turbine operates under a 60-ft head with

expected output of

MW. Determine a suitable design starting time,

T,,

expected pressure rise, and the minimum flywheel requirement. Make any

necessary assumptions.

POkLBERHOUSES

RNB

FAClLlBlES

TYPES OF POWERHOUSES

Powerhouses for hydroplants usually consist of the superstructure and the substruc-

ture. The superstructure provides protective housing for the generator and control

equipment as well as structural support for the cranes. The superstructure may

provide for

erection bay that protects component assemblies during 'inclement

weather.

The substructure or

foundatiofis of the powerhouse consists of the steel and

concrete components necessary to form the draft tube, support the turbine

stay

ring and generator, and encase the spiral case.

control room is also included in

the powerhouse to isolate the control systems from generator noise and to provide

a clean and comfortable

environrr~nt for operators.

Conventional Installations

Conventional powerhouses differ depending on how they are oriented or con-

nected with the dam. Some are structurally connected to the dam; others are

located some distance from the dam and a penstock carries the water from the

intake to the powerhouse. Figure 11.1 is a

siniplified sketch of the general arrange-

ment for powerhouses of the conventional type. Different ways of connecting the

powerhouse to the impounding dam or the tunnel penstock are illustrated. Figure

11.2 is a plan layout and cross section for a typical powerhouse of the conventional

type showing the

arrangelnznt of the various components. The shaft of tlie runner

and generator is vertical and water flow is normal to the line of turbine units. Some

Powerhouse with earth

dam

owwhouse with

Figure

General arrangements for powerhouses for conventional hydropower

installations.

rypes of Powerhouses

Butterfly

Valve

L.1

fY'f

-I

,887

ax.

T.W.

El.

4507.3

502

498

Transverse section

thru

tunit

Glendo Powerplant

Figure

11.2

Plan layout and cross-section of conventional powerhouse.

SOURCE:

U.S.

Bureau of Reclamation.

powerhouses are oriented differently to accommodate excavation and site prepara-

tion problems. Figure 11.3 shows how the powerhouse at Elephant Butte Dam in

New Mexico is arranged, and Fig. 11.4 shows how the third powerhouse at Grand

Coulee

Dam

Washington was added to an existing dam to accornniodate the

discharge of water from the dam to the turbines. Each development

rnay require

ialem ioj @sap e smo11c

S!L~J,

'A[lcluoz!ioq palunolu air! slje~[s au!qrnl aql 'sl!un

ielnqnl pue sl!un qrnq Bu!z![!gn suo!~c~~c~str! iamodoipAq peaq-MO~ ql!~

.luc[d iamodoipAq jo adL1 rooplno-yras c jo qslays

leuo!lsas-ssois c smoqs

9'1

arnS!d 'slucld ia~od pr!aq-MO[ jo slsos asnpar

ue3

Spuanbaij pue lue~d ia~od aql jo ainsodxa 3!laylsae arour e 8u1p!nold jo a8eluenpe

aql ahey suo!lel[elsu! ysns

.JOOJ

ainlsrulsqns aqi u! s%u!uado ro says~ey @norql

sluauoduro:, l!un aql aAour ley1 sauei:, apqour

rogalxa autp!~ord pue sIaAaI ainl

-3rulsqns ayl u! luaurdpba IIe %u!]esd[ sanlohty uo!leIIelsty iooplno-!was

.@s!lserd are suo!lenelsu!

iooplno JaqlaqM alels!p suo!l!puos iayleaw arIJ; ~uo!lenelsu! rooplno ps!dAl

e jo yder8oloyd e s! s.1

ain%!~ 'uo!le[[el~u! iooplno ue ty papn[su! asway![

sl!un iaIIclus roj awls anqolu e pue sl!un ailre[

JOJ

suers

iooplno

.A[qmasse

iolciaua8 pue au!qinl aql slioddns arnlnnilsqns aqL .asnoqiamod roopino

pa[(es s! sq~ '[elaur jo 8uuanos jooid~aqlF!aM e ql!~ ioleiaua8 aql lsalord pue alnl

-snilsiadns ql!~ asuads!p 01 [es!urouosa s!

suo!lenelsu! iamodoipAq auros

suo!aelleisul ~ooprno-!was pue ~ooptno

.uo!leurelaax jo nearng

'sn

:33xnos

'UO~~U!~SCM 'urea aaln03 pucrn

1uaura8ue~~e asnoqrafiod

p'll

alnS!d

.X~qurassc iolcraua8 puc 'aqnl ~vip

'ZU!SC?

ICJ!~S

ayl

SJoualur ar[l

.IOJ

sun!suaryp

qs!unj 01 siain~scjnueur ioleiaua8 pue au!qinl at[$ 103 Aicruolst~s s!

~8!s3p

pug iod .sa!pnls Al![!q!scaj u! pasn aq ucs ~cql suo!suarrr!p Zu![[o~luo~ sane

raldey3 u! paluasaid Su!uo!suaru!p lnoAel ayl :sljcqs Ics!liaA aney 01 suo!~~[lelsu!

Alpedes 1a3ie1 103 as!lscrd Icnsn aql s! $1 .aqnl Ijelp aql jo varc la[lno alp pue

'8u!se3

~EJ!~S

aql 'rolcia~a8 aql alcpoururosoc 01 sluaural!nbai aL[l Aq paulano8

8u!ppnq ayl jo az!s ar[L .rrralqord [cinl>al!~lsrc puc [crnlsn.rls c /(picrrrud s!

asnoyla~od ayl jo u8!saa .uo!lsnilsuos

Smouosa lsaq arp u!e8 01 raplo u!

a)!s ayl ]e I(qdei8odol pm s8oloa% aq a]cpoururosse 01 s~ilarrradu~~~e pads

(0~61)

asnoq~amod.."

VUL

Powerhouses and Facilities Chap.

Types

of Powerhouses

Figure

11.5

Outdoor-type powerhouse arrangement. SOURCE: Idaho Power Co.

Figure

11.6

Semi-outdoor-type powerhouse arrangement.

Bulb

type

Figure

11.7

Low profile, powerhouse arrangements for tubular and bulb-type

hydro developments. SOURCE

KMW,

Sweden.

passages that can be accommodated in low-profile powerhouses to protect the

turbines and generators. For some installations no powerhouse has been required.

Figure

11.7

shows a cross-sectional sketch of two different types of turbines with

representative powerhouse designs. Normally, the powerhouse and civil works are

longer in the direction of flow and narrower than conventional vertical-shaft

mounted turbines and require less excavation depth to accommodate the turbine

equipment and water passages.

In special cases where space for powerhouses and spillway is critical, the

turbines and generators can be housed in the overflow spillway portion of a dam.

The gantry cranes and electrical facilities are accommodated on decks bridging

across the overflow spillway. Figure 11.8 shows a cross-sectional sketch of such

installation.

Underground Installations

To accommodate narrow canyon locations and to reduce environmental

impact, powerhouses can be built underground using tunnel construction. This

requires access tunnels to deliver equipment. Figure 11.9 gives

example of an

underground installation. The excavated volume should be kept to a

minimum and

all functions of air conditioning and ventilation adequately planned. Underground

powerhouses are very specialized in their design and thus beyond the scope of

this