Winter difficulties in the operation of the Dniepr sequence of hydroelectric stations

Conclusions

• 1. When designing a hydro development it is necessary to study thoroughly the winter regime of the river in order to predict possible ice difficulties and to work out measures for controlling them (electrical heating of the trash racks of the turbine and TWS system intakes, mechanization of the operations involved in raising and cleaning the racks, construction of a boom for holding back snow slush).

• 2. Hydroelectric stations must be equipped with measuring devices for timely assessment of the meteorological situation: a GM-6 hydrometeorological station, GR-21 or GR-41M electrical thermometers, and a PGP-type remote-controlled instrument for measuring the head differential of the intake racks.

• 3. If the power system operating conditions do not permit creating tranquil water conditions in the reservoir for the formation of an ice cover in front of the station intake, the most effective way of combating shuga and snow slush is to raise the upper sections of the rack to allow passage of the shuga and snow slush through the turbines. However, in this case it is necessary to eliminate the possibility of the entry of foreign objects into the turbines, for which purpose the space in front of the intake should be cleaned of driftwood and other submerged objects.

• 4. The TWS system should be supplied from two intakes located in zones with different regime conditions; for example, one intake in the upper pool beyond the zone of influence of the stream approaching the intakes and the other on the lower pool side.