Design of penstocks of pumped-storage stations

Autor: I. A. Polinkovskii, A. V. Egorov, S. A. Berezinskii, V. S. Lashmanova
Rok vydání: 1985
Předmět:
Zdroj: Hydrotechnical Construction. 19:180-187
ISSN: 1570-1468
0018-8220
DOI: 10.1007/bf01429267
Popis: When designing the penstocks of pumped-storage stations (PSSs) it is necessary to solve a wide range of new engineering problems. They include first of all the selection of the route of the penstocks with consideration of the engineering-geologic conditions and general layout of the station. As a rule, for the PSSs examined in this article the route of the penstocksruns along a slope composed~soil rather than rock. Traces of landslide phenomena are often found already during surveys. Therefore, when designing penstocks it is necessary to assess the stability of the slope and to develop engineering measures to increase it. Such measures include primarily flattening of the slope, control of the levels and drainage of groundwaters, and grading and stabilizing the slope with construction of a surface water drainage system. The general and decisive conditions for selecting the design of a penstock for the investigated type of PSS are: location of the open route of the penstocks on slopes composed of soils; averageslope of the route of the penstocks 1:6-1:10; the relatively small design head (90-120 m) for PSSs, which for units with an individual capacity of about 20OMWpredetermines the turbine discharge of up to 250 mS/sec and penstock diameter from 6.5 to 8 m. Here it is timely to examine the problem of the reliability of the designs of metal penstocks, on the one hand, and of reinforced-concrete and concrete-encased penstocks, on the other. Despite the fact that among construction materials metal is distinguished by a high homogeneity and stability of mechanical properties, metal structural elements of a penstock can have defects, which in individual cases cause its rupture. The occurrence of cracks in the penstock lead to its avalanche failure under a load, since in the design of a metal penstock there are no elements restraining the development of cracks. For this reason hydrotechnical construction practice and the construction regulations (SNIP 11-50-74) specify the need to take appropriate measures to protect the powerhouse from the consequence of failure of the penstock. Such measures include either a muta! arrangement of the station and route of the penstocks which provides diversion of the failure flow away from the powerhouse or the construction of a special structure deflecting the failure flow. It is obvious in this case that the failure flow also should not cause erosion along the route of the penstocks, reducing to naught the measures on deflecting the flow. In layouts with reservoir powerhouses
Databáze: OpenAIRE
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