The presence of harmonics introduces disturbances and losses in electrical systems that cause malfunctions and inefficiencies. The harmonic emission levels are progressively increasing because the presence of non linear loads and distributed generation from renewable energy resource.
The assessment of the effects on electrical systems is an important goal for modern industries, where the disturbances cause both damage and inefficiencies. According to the Leonardo Power Quality Initiative (LPQI) and the research by the Electric Power Research Institute (EPRI), poor power quality is estimated to cost the European economy up to €150 billion annually and the U.S. sees losses ranging from $119 billion to $188 billion, when the 80 percent of power-quality disturbances are generated within a facility.
To evaluate the impact of disturbances and inefficiencies, several methods were presented, based on the definitions and indications contained in the standards such as the IEEE std 1459. These malfunctions and inefficiencies can be reduced with the use of filtering systems, such as passive filters. series.
To carry out the necessary measures to understand the effectiveness of the filters, it is possible to use measurements in the time domain which, carried out for limited periods, but with many repetitions, can offer a valid response to the efficiency achieved.