Hydropower and nuclear power are the most important sources of energy in
Sweden. Half of Sweden's total energy production is produced in the
hydropower plants along the Swedish rivers. The size of the hydropower
units in these power plants varies. The biggest hydropower unit in Sweden,
Harsprånget G5, has a rotating structure that weighs over 1000 ton and
generates almost 500 MW. Hydropower units use the kinetic energy of the
falling water and transform it to electrical energy. In a hydropower unit
as big as the G5, approximately 500 m3 water passes through the turbine each
second. The enormous flow of water through the turbine and the enormous
mass of the rotating structure results in huge loads on the bearings that
supports the rotating structure.
The characteristics of generator bearings and the loads acting on it has
been analysed in this thesis. A method to determine bearing data from
measured loads and displacements in the generator bearing has been
developed and evaluated. The loads are measured with a method that allows
bearing loads to be measured without disassemble the bearing. Disturbances
that affect these measurements has also been analysed. MATLAB were used for
mathematical computation and analysis.
Data measured at the hydropower units were analysed and some disturbances
were found. Most of the measured data were affected by 50 and 100 Hz
disturbances. To avoid the influence of these disturbances appropriate
filters should be used. Some strange frequency characteristics were also
found in the measurements performed with the inductive displacement
sensors. The huge magnetic field that surrounds the hydropower unit probably
affects the inductive displacement sensors. Inductive displacements sensor
should therefore be avoided in displacement measurements near generators at
hydropower units. It is possible to calculate the bearing data for the
generator bearing if the displacements and loads in the generator bearing
are measured correctly. The bearing data for the generator bearing is
calculated in the generator axles static position. The static posit...
