Flickering light and voltage fluctuations Importance, effects and measurement »»Do you have symptoms of dizziness in areas illuminated by artificial light? »»Your electrical and electronic devices turn off or do not work correctly?
Fliker and voltage fluctuations Flicker, otherwise known as the flickering light parameter, is directly related to fluctuations in the supply voltage. This parameter determines the degree of voltage fluctuations in power grids and allows to assess the impact on the human body. Where there are exceeded levels of the flicker specified in the standards, it is required to use mitigation techniques to limit the effects of voltage fluctuations. Voltage fluctuations have the greatest effect on incandescent lighting. Therefore, the importance of the flicker is lower at present because of the more common use of LED lighting, which is more stable and less sensitive to voltage fluctuations. In many countries, the measurement of a flicker is important for energy suppliers who have to meet the power supply parameters specified by the standards. Exceeding the parameters of standards is also related to the application of penalties, which makes flicker control more common.
What are voltage fluctuations and what causes them? Voltage fluctuations can be described as repetitive (periodic) or accidental changes in voltage envelope due to sudden load changes. In Figure 1, the shape of the voltage waveform shows changes, which is evident in the periodic envelope changes (here a sinusoid). In practice, the voltage envelope profile will depend on the type and duration of the load.
Figure 1. Voltage waveform with envelope. There are clear voltage fluctuations.
Loads that can cause voltage fluctuations include: 1. Installations with frequent engine starts 2. Motor drives with cyclical operation 3. Arc welding machines 4. Arc furnaces
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