| dc.description.abstract | A transformer is an electrical device that can transfer and convert electrical
energy from one or more circuits to another through magnetic coupling and based
on the principle of electromagnetic induction. The performance of the transformer
is also limited by the magnetic flux of the iron core. For the core of ferromagnetic
transformer, we must pay attention to the saturation limit of the core.
Understanding the influence of materials and manufacturing parameters on the flux
density distribution will enable transformer design designers to improve core
performance. Magnetostriction is a property of ferromagnetic materials that
changes their geometric dimensions when exposed to a magnetic field. There are
several factors that cause damage or disturbance to the transformer due to
magnetostriction, namely heat, vibration, noise and harmonics. Transformer
disturbance starting from the transformer core lamination will occur a
magnetostriction phenomenon, causing vibration and noise, heat, then will produce
Total Harmonic Distortion (THD) above the threshold value. This study
investigates the distribution of flux density in the transformer core layer and its
contribution to harmonics, vibration and emitted core noise. Investigations were
carried out experimentally on the layers of the transformer core construction and
then the results were verified analytically with an equation approach on a
theoretical basis, as well as with the measurement results. When the transformer is
no-load, the effect of magnetostriction on the harmonics of the ITHD percentage is
high when the flux density of 0.9 Tesla is 92.21% and fluctuates up and down, in
the lowest range of ITHD 47.43% when the flux density is 1.5 Tesla. The dominant
harmonics are in the 1st, 3rd and 5th order. Against vibration, at a magnetic flux
of 1.4 until 1.6 Tesla, the vibration reaches its peak before the transformer is
saturated, and the vibration will decrease after saturation. Against noise and
magnetic flux of 1.4 until 1.6 Tesla, magnetostriction in the core layer is
characterized by increasing noise levels then at 1.7 until 1.8 Tesla the noise level
drops sharply to 77.5 dBA and 76.9 dBA. So this research will provide a reference
in the design of the transformer core in order to improve the performance of the
transformer. | en_US |
