Reconstruction of dirt-keeping grates 2SCHP/1 of Nizhnekamsk Hydro- Power Plant

Dirt - keeping grates are designed for prevention of entrance of floating and snag (bulrush, wood, various technical wastes) in flowing part of the hydro-aggregates.

DKG in water reception hole undergoes vibration, resulting in fatigue breakdown of elements (rods, bushes, fixing pins, braces) of the construction.

During the flood the pressure front of the dam of hydro power plant gathers a lot of floating dirt, the area of which may reach 650 х 30 m and depth of 1 meter, part of this dirt clogs the rods of packages of dirt-keeping grate. Because of irregular passage of water through DKG construction, the dynamic load upon the carcass of DKG increases and the non-projected vibration of o\its elements occurs.

In 2002-2004 ITTS JSC "Trust Gidromontazh" (Moscow) researched and tested the operation of DKG and recommendations were given regarding vibration-stable construction of the grate for Nizhnekamsk hydro power plant.

Goal of reconstruction will be improvement of dynamic stability of package rods and braces of carcasses by changing the calculation scheme of DKG construction with withdrawal from resonance frequencies. This provides the long life of the rod packages and bearing carcass of DKG.

As a result of reconstruction we expect the increase of inter-repair period of dirt-keeping grate at least by twice. The duration of inter-repair period of dirt-keeping grate till reconstruction constituted 4 - 6 years, after reconstruction it will be 8 - 12 years.

In 2005 - 2006 according to capital construction plan of Nizhnekamsk hydro power plant the two DKG were reconstructed, of them 4 - in 2006.

Work continue.