{"id":2706,"date":"2025-05-23T16:38:49","date_gmt":"2025-05-23T14:38:49","guid":{"rendered":"https:\/\/pqs.com.pa\/?page_id=2706"},"modified":"2025-05-23T16:41:57","modified_gmt":"2025-05-23T14:41:57","slug":"flicker-and-voltage-fluctuations","status":"publish","type":"page","link":"https:\/\/pqs.com.pa\/en\/flicker-and-voltage-fluctuations\/","title":{"rendered":"Power Line Flicker and Voltage Fluctuations for enhanced power quality"},"content":{"rendered":"
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Flicker refers to the perceived fluctuation in light intensity that occurs when voltage fluctuations impact lighting systems. It is often caused by rapidly changing loads in the electrical network. It can be visually discomforting and can affect the performance and lifespan of sensitive equipment, especially in industries that rely heavily on precise lighting conditions or use sensitive equipment.<\/p><\/div>

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\"What<\/span><\/div>
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Flicker is characterized by voltage variation typically within the range of \u00b110%. These voltage fluctuations occur multiple times over a specific period, resulting in perceptible changes in light output. The variations can happen at irregular intervals and may differ in duration and intensity. The frequency of the variation, often measured in cycles per second or hertz (Hz), determines the rapidity of the flickering effect. A higher frequency of voltage fluctuations can lead to more pronounced flicker, which can be particularly noticeable in lighting systems where rapid changes in brightness can be visually disturbing.<\/p><\/div><\/div><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Flicker Effects<\/h2><\/div>
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Headaches\/Visual Effects<\/p>

Neurological Effects<\/p>

Seizures in photosensitive epileptics<\/p>

Unperceived neurological effects<\/p>

Unperceived retinal effects<\/p>

Visual Effects<\/p><\/div>

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Source of Flicker<\/h3><\/div>

Low frequency fluorescent<\/p>

Amplitude-moderated flickering light<\/p>

Various<\/p>

Light-emitting diode<\/p>

Various<\/p>

Computer monitor<\/p><\/div>

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Frequency (Hz)<\/h3><\/div>

100<\/p>

20-75<\/p>

Various<\/p>

Up to 200 Hz<\/p>

76-162<\/p>

70-110<\/p><\/div>

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Source: R. Inger el al. PLoS One, 2014<\/em><\/p><\/div>

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Flicker Measurement<\/h2><\/div>

In accordance with the international electro-technical standard IEC 61000-4-15, the specifications for flicker measurement equipment are meticulously outlined. This standard establishes the framework for evaluating voltage flickering, ensuring a consistent and universally accepted method.<\/p>

A flicker meter comprises multiple functional blocks designed to replicate the characteristics of a 230V\/60W incandescent lamp (referred to as the reference lamp) and the intricate dynamics of the human perception system, modeled on the eye-brain interface.<\/p><\/div>

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The assessment of flicker involves deriving momentary values, from which Perceptibility Short Term (PST) is calculated using a statistical process over a standardized 10-minute observation interval. Simultaneously, the long-term flicker (PLT) is calculated as the cubic mean of multiple PST values over a standardized two-hour period. The calculation and scaling algorithm for the perceptibility value are intentionally crafted. A PST value of 1.0 is strategically aligned to a level at which 50% of test subjects perceive the flicker to be both noticeable and irritating. This ensures that the measurement is not only objective but also reflective of the human experience with flickering.<\/p><\/div>

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\"Quantifying<\/span><\/div>
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As seen in the equations for PLT and PST, both the voltage variation and the number of switches (denoted as \u201cr\u201d) have an impact on the level of flicker. Voltage Variation (V): The voltage variation, expressed as a percentage, represents the magnitude of the voltage fluctuations within a given time period. A higher voltage variation can result in more significant effects, as the changes in voltage levels have a more noticeable impact on the lighting system. Number of Switches (r): The number of switches, denoted as \u201cr\u201d refers to the frequency or rate at which the voltage fluctuations occur. A higher number of switches indicates that the voltage is changing more frequently, potentially leading to a more pronounced flicker effect.<\/p><\/div>

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\"Quantifying<\/span><\/div>
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The timing and duration of these switches can impact the perceived flicker characteristics. Both the voltage variation and the number of switches contribute to the overall flicker level. While the voltage variation determines the magnitude of the fluctuations, the number of switches influences the frequency and pattern of the flicker. It is important to consider both aspects when evaluating and mitigating flicker issues in lighting systems to ensure a comfortable and visually stable environment for users.<\/p><\/div>

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