Protection of outlet channels of hydroelectric power stations
Depending on the water power plant construction technology used and the type of water turbines used, the water outlet is via a long outlet channel.
The speed the water reaches in the outlet duct is quite high. There is a dominant attraction current that attracts fish that want to swim upstream. When the outlet channels need to be closed, e. g. during inspections or due to turbine failure, it may occur that after the water is pumped out of the outlet channels, there may be very large quantities of fish. Usually access to these channels is quite limited and is usually done through small manholes or locks. Before carrying out any work in these channels, fish remains have to be cleaned, which prolongs the time of the plant’s downtime.