Small Decentralized Hydropower Program National ... - Cd3wd.com
Small Decentralized Hydropower Program National ... - Cd3wd.com
Small Decentralized Hydropower Program National ... - Cd3wd.com
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longitud total de estos vertederos debe ser, en<br />
lo posible, igual o mayor de 10s siguientes<br />
valores:<br />
Ll = 20 m por cada m31s de1 caudal<br />
por captar.<br />
L2 = 0.50 m. por cada m3;s. de1 caudal de<br />
mkima avenida siendo el nivel de 10s<br />
puentes etc. 5 1.50 encima de la cresta<br />
de 10s vertederos 6:<br />
L3 = 0.20 m. por cada m31s. de1 caudal mkximo,<br />
si el nivel de 10s puentes es 1.2.50 m.<br />
encima de las crestas de Vertederos.<br />
Los Vertederos Aliviadores pueden ubicarse<br />
en 10s siguientes sitios:<br />
- Encima de1 Barraje Principal (1)<br />
- Al borde de la Ante&mara (4)<br />
En la zona de CaptacGn, antes de la reja<br />
(3)<br />
Los Vertederos de esta zona quedar8n todos<br />
al mismo nivel, sumfindose sus longitudes para<br />
llegar al valor deseado.<br />
8. Desripiadores y Desurenadores<br />
Los rios provenientes de la Sierra peruana<br />
traen casi todos acarreo fuertes, tanto de fondo<br />
<strong>com</strong>a en suspensibn, debido a la falta de<br />
vegetaci6n. Por la misma razbn, generalmente<br />
son escasos 10s cuerpos flotantes en estos rios.<br />
Tambien en el curso de 10s canales entran en<br />
muchos cases, cuerpos s6lidos que son arrastrados<br />
por el agua hacia las Gmaras de<br />
carga y a las turbinas si no hay dispositivos de<br />
decantaci6n en esta c&mara.<br />
Para centrales con Turbinas Pelton y<br />
Francis, se re<strong>com</strong>ienda eliminar todos 10s<br />
granos de arena de diametro mayor O-.3 mm, 6<br />
sea 10s que tienen una velocidad de decantaci6n<br />
en aguas tranquilas de 4 cm/s. 6 m&s. Adem&,<br />
debe inhibirse la decantacidn de arena en 10s<br />
canales, eliminando :os granos mayores ya en la<br />
regi6n de la bocatoma.<br />
Se@ las condiciones locales, tanto en el rfo<br />
<strong>com</strong>a en la zona de1 canal y la turbina, se<br />
dispondrkn por consiguiente 10s desarenadores<br />
en Toma y en Taza (Cgmara de Carga) en una<br />
de las <strong>com</strong>binaciones siguientes:<br />
1. Desarenador Preliminar o solamente<br />
Desripiador en la Toma y Desarenador<br />
<strong>com</strong>plete en Taza.<br />
2. Desarenador Completo en Toma y Auxiliar<br />
en Taza.<br />
148<br />
7. To eliminate the excess water during high<br />
water season, spillways are constructed in<br />
the intake area to limit the maximum level<br />
of water so that the level is kept under the<br />
gate manipulatio? bridges and so ac-<br />
cessways and other parts of the installa-<br />
tion which are kept above floods. The total<br />
length of these spillways should be kept to<br />
the extent possible equal to or above the<br />
following values:<br />
L.l = 20 m for each m% of water to be<br />
diverted through the intake.<br />
L.2 = 0.50 m for each ma/s of the max-<br />
imum amount of high water, the level<br />
of the control bridges, etc. being<br />
more than 1.50 m above the crest of<br />
the spillways, or<br />
L.3 = 0.20 m for each ma/s of the max-<br />
imum amount of water, if the level of<br />
the control bridge is more than 2.50<br />
m above the spillway crest.<br />
The spillways may be placed in the<br />
following sites:<br />
- Above the main dam (1)<br />
- At the edge of the antechamber (4)<br />
At the intake area, before the trash rack<br />
- (3)<br />
The spillways in this zrea should all be at<br />
the same level. Their lengths should be ad-<br />
ded to get to the desired valrle.<br />
8. Sand traps<br />
Almost all of the rivers <strong>com</strong>ing down<br />
from the Peruvian Sierras bring heavy<br />
material along the bottom, as well as in<br />
suspension, due to the lack of vegetation.<br />
For the same reason, there is little floating<br />
debris in these rivers. Along the canals<br />
solid materials frequently enter and are car-<br />
ried by the waters toward the load<br />
chambers and to the turbines when there<br />
are no measures taken to prevent sedimen-<br />
tation in these chambers.<br />
For stations using Pelton and Francis<br />
turbines. elimination of all sand grains of<br />
over 0.3 mm is re<strong>com</strong>mended, that is, those<br />
with sedimentation speed in still waters of<br />
4 cm/s or more. Sedimentation sb,luld also<br />
be inhibited at the intake of the canals,<br />
eliminating the bigger grains of sand<br />
already at the intake region.