CLASSIFICATION OF SMALL HYDROELECTRIC STATIONS AND STANDARDIZATION OF THEIR UNITS.

One of the most effective ways of reducing costs is to eliminate individual designing of technological equipment and to use at small hydros unified series-produced equipment, standardization of layouts, types, and structural elements of turbines and, on the whole, of the turbine-generator units, since in this case the cost of equipment is reduced and the quality of manufacture and efficiency of operation increase. To increase the economic efficiency of the equipment being used, it is expedient to examine the use of overdrive transmissions between the turbine and generator. For medium-head plants the most suitable is a mixed-flow turbine with a horizontal or vertical shaft and fixed or adjustable gate apparatus. Sometimes overdrives can be used for increasing the rotational speed of the generator. Pelton wheels are used for high heads. As a result of the studies the four most widespread types and layouts of turbine equipment were established with consideration of possible unification: vertical propeller with fixed adjustment of the runner blades; horizontal axial with a S-shaped draft tube and outlying horizontal generator; horizontal axial straight-flow with an outlying vertical generator; vertical mixed with a curved draft tube and vertical generator.