7.4. Dips and Swells
Dips and Swells records Swells, Dips, Interruptions, and Rapid Voltage Changes.
Dips and Swells are fast deviations from the normal voltage. Magnitude may be ten up to one hundred of
volts. Duration may vary from a half cycle to a few seconds as defined in IEC61000-4-30. The Analyzer
allows you to choose nominal or sliding reference voltage.
During a dip the voltage drops, during a swell the voltage rises. In 3-phase systems, a dip begins when
the voltage on one or more phases drops below the dip threshold and ends when all phases are equal to
or above the dip threshold plus hysteresis. A swell begins when the voltage on one or more phases rises
up to the swell threshold and ends when all phases are equal to or below the swell threshold minus
hysteresis. The trigger conditions for dips and swells are threshold and hysteresis. Dips and Swells are
characterized by duration, magnitude and time of occurrence. The following pictures explains this:
Picture: Characteristics of a voltage dip
Picture: Characteristics of a voltage swell
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