High Frequencies in AC Distribution Lines: a New Technical Challenge.

In the last ten years it has been observed a considerable growth of non lineal electrical charges. The number of devices, such as PC or compact fluorescent lamps, has dramatically increased due to the lack of proper regulations when the power is under 100 W. As a result, the scientific and technical community has agreed on the possible problems related to massive use of these non lineal charges.
A problem in electrical pollution problem, not widely documented, is the presence of high frequency currents in AC distribution lines. These currents occur when a chopper or inverter configuration is connected through a rectifier to an AC line, without a suitable filter. The choppers, normally used to compensate the power factors, is another typical source of this problem. Therefore, it is possible to detect signals in which the amplitude reach the 50 % of the 50/60 Hz amplitude signal with frequencies that range between 20 kHz and 100 kHz.
In this work, the results of a study of different street led lamps
with electronic drivers from different manufacturers are presented. These lamps have an elevated level of high frequencies in the first quarter of each semicycle.
The spectrum analysis indicates a different content, depending on the samples mode of high sample rate instruments.
The results of measurements with power analyzer show a high power factor and low harmonic distortion, but they do not show any evidence of the presence of these currents.
As a conclusion, the increment of high frequencies currents in AC line adds a new level of electrical pollution, more difficult to detect and measure and whose effect will be the subject of study.