Harmonic distortion refers to the presence of unwanted frequency components in an electrical signal. Harmonics can appear in AC power systems due to non-linear loads, such as LED lighting systems that use electronic drivers (such as those found in switching-mode power supplies). These non-linear loads generate highly distorted current waveforms and result in a distorted AC voltage waveform with high Total Harmonic Distortion (THD).

The problem with high levels of harmonic distortion in an electrical system is that it can create inefficiency, overheating, and interference with other electrical equipment connected to the same system. These excessive harmonics can damage or reduce the lifespan of electronic equipment, increase energy consumption, and cause unexplained malfunctions in the system.

Taking mitigation steps to reduce harmonic distortion in an LED lighting system is important. A common method to correct high harmonics in AC power systems is to use filters or power conditioners to attenuate or eliminate the harmonics. Another solution is to use power supplies with Power Factor Correction (PFC) technology, as they provide a more linear input current that reduces harmonic content in the system.