Resumo:
Power supplies for electronic devices are increasingly a significant segment of total load in
power systems, many of which can impact on the power quality, as well as can suffer from the
disturbances present in it. Thus, many standards and recommendations been and are being
developed to improve the compatibility between power systems and electronic devices,
including standards that define limits for harmonic distortions and voltage sags.
In this bias, this work shows some standards and recommendations pertinent of harmonic
distortion, as well standards for immunity tests of devices submitted to voltage sags. In face
this, experimental tests were realized with computers power supplies in controlled
environment laboratory, where the basic parameters were recorded to permit detailed analysis
of the power condition under different voltage excitations. Thus, in first step was checked the
compatibility and immunity this equipment under test up high levels of voltage harmonic and
posteriorly, this phenomena associated to voltage sag up 50% of the nominal voltage.
Based on temperature, output voltage (DC), consumption current and function of power
supplies, this work proves that this device can supported harmonic voltage distortion much
larger than commons limits recommended (up 10 times more). Beside was certificated that the
power supplies with power factor corrector (PFC) supported much more high voltage
distortion levels, besides to have better performance and consumption less harmonic current
than traditional design of power supplies. The results show that different waveform can affect
the performance of load, principally when occur concomitantly the voltage sags, however any
failure was observed for this case.
From this work is feasible to think that the regulations, principally those concern the harmonic
distortion, need more frequently studies and updates, considering the existence of many
models of devices, in addition the better design in it. Also stay clear the necessity more
investigation with different kinds and topology of power supplies for the comprehensive
evaluation their performance, besides to evaluate the compatibility with the standards and
recommendations, considering that the present harmonic distortion limits can be considerate
much severe as to the evaluated objects.
