High-pressure penstocks for hydroelectric power stations, made from steel and reinforced concrete

Abstract

High-pressure penstocks are widely used to convey water to hydroelectric power stations. They usually involve special tunnels cut in the rock: this greatly adds to the cost of station construction.The most popular design for a penstock is a metal cylindrical casing of factory-rolled shells. The thickness of the metal casing depends linearly on the force per unit length ( Fig. 1),In present high-head stations, the diameters of the steel pressure pipes are usually limited by the thickness of the metal casing. For example, at the Krasnoyarsk hydroelectric station, each unit has two penstocks 7.55 m in diameter instead of one 10.9 m in diameter; at the Nurek station, 800-900 m of penstock passes through the rock to each unit, i.e., nine lines 6 m in diameter instead of three 10 m in diameter; at the Ingursk station, from the surge tanks to each unit special penstocks are also planned, five in all with a length of the order of 800 m. Joining the penstocks leads to such an increase in the parameters that it is practically impossible to make them of metal owing to the great thickness of the casing. Apart from bends and forks penstocks can also be made from steel wrapping. However, the technology of making steel pipes by wrapping sheets has not yet been developed in the USSP..