Which type of load is most likely to create harmonic distortion?

Non-linear loads are significant sources of harmonic distortion in electrical systems. These types of loads do not draw current uniformly over the entire cycle of the waveform, resulting in a distortion of the voltage and current waveforms. Instead of producing a smooth sinusoidal wave, non-linear loads, such as computers, LED lighting, and variable speed drives, draw current in abrupt pulses rather than a continuous flow.

As the load draws current in this pulsed manner, it generates harmonics—additional frequencies that are integer multiples of the fundamental frequency (typically 60 Hz in North America). This can lead to various issues in the electrical system, including overheating of components, reduced efficiency, and interference with communications equipment.

In contrast, linear loads, including resistive and capacitive loads, draw current that is directly proportional to the voltage and tends to maintain the integrity of the waveform, making them less likely to introduce significant harmonic distortion. Thus, while certain other types of loads can affect system performance, it is the non-linear loads that primarily contribute to harmonic distortion.