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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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