Eurolight
In the lighting industry, Total Harmonic Distortion (THD) is a frequently mentioned concept. So, what exactly is THD? Simply put, harmonic distortion refers to the additional harmonic components that appear in the input signal, components that are not part of the original input signal. In the lighting field, THD is closely related to frequency, reflecting the content and impact of harmonics in the power system.
How are THDs generated?
1. Switching power supply characteristics: When the switching power supply of an LED lamp is operating, the current is input in pulses rather than flowing continuously, resulting in a non-sinusoidal current waveform and the generation of harmonics.
2. Nonlinear load: The voltage-current relationship of an LED is nonlinear; it only conducts when the voltage reaches a threshold, causing distortion in the current waveform and further generating harmonics.
The dangers of harmonics
1. Power Grid Impact: Harmonics cause voltage waveform distortion in the power grid, increase transmission line losses, and reduce the overall efficiency of power generation and transmission equipment.
2. Equipment Interference: Nearby electronic equipment may experience abnormal screen displays (such as snow), communication noise, or even malfunctions in protection devices, threatening the stability of the power system.
How to select the correct THD of LED lights?
LED lights THD are mainly caused by the characteristics of the driver power supply and the nonlinearity of the load, which may lead to increased grid losses and equipment interference. In this case, Therefore, in Nigeria, where electricity supply is unstable, choosing the appropriate THD for LED lighting fixtures is even more important.
For residential lighting with small quantities for a project, the THD for LED lights, such as LED downlights, it is ok to be 20% THD-30% THD.
But for commercial lighting like LED panel lights, with large quantities for a project, it should be less than 15% ( THD<15%), which will be better.
However, for high power LED lights which are more than 50W, such as LED high bay lights, outdoor LED street lights, floodlights, etc, the THD<10% or 15% will be the good choice.