MI 2893 / MI 2892 / MI 2885
Measurement methods
197
Figure 161:Voltage dip related screens on the instrument
A voltage dip is characterized by following data: Dip Start time, Level (U
Dip
) and Dip duration:
U
Dip
– residual dip voltage, is the lowest U
Rms(1/2)
value measured on any channel during the dip.
It is shown in Level column in the Event Table on the instrument.
The Dip Start time is time stamped with the time of the start of the U
Rms(1/2)
of the channel that
initiated the event. It is shown in START column in the Event Table on the instrument. The Dip
End time is time stamped with the time of the end of the U
Rms(1/2)
that ended the event, as
defined by the threshold.
The Dip Duration is the time difference between the Dip Start time and the Dip End time. It is
shown in Duration column in the Event Table on the instrument.
Voltage swell
Standard compliance: IEC 61000-4-30 Class A (Sections 5.4.1 and 5.4.3)
The Swell Threshold is a percentage of nominal voltage defined in CONNECTION menu. The swell
threshold can be set by the user according to the use. Swell Hysteresis is difference in magnitude
between the Swell start and Swell end thresholds. Instrument event evaluation in Event table screen
depends on Connection type:
On single-phase system (Connection type: 1W) , a voltage swell begins when the U
Rms(1/2)
voltage
rises above the swell threshold, and ends when the U
Rms(1/2)
voltage is equal to or below the
swell threshold plus the hysteresis voltage.
On poly-phase systems (Connection type: 2W, 3W, 4W, Open Delta) two different view can be
used for evaluation simultaneously:
o
Group view
with selected ALL
INT
view: A swell begins when the U
Rms(1/2)
voltage of
one or more channels is above the swell threshold and ends when the U
Rms(1/2)
voltage
on all measured channels is equal to or below the swell threshold plus the hysteresis
voltage.
o
Phase view Ph.: A swell begins when the U
Rms(1/2)
voltage of one channel rises above the
swell threshold, and ends when the U
Rms(1/2)
voltage is equal to or below the swell
threshold plus the hysteresis voltage, on the same phase.
A voltage swell is characterized by following data: Swell Start time, Level (U
Swell
) and Swell duration:
U
Swell
– maximum swell magnitude voltage, is the largest U
Rms(1/2)
value measured on any channel
during the swell. It is shown in Level column in the Event Table on the instrument.
The Swell Start time is time stamped with the time of the start of the U
Rms(1/2)
of the channel
that initiated the event. It is shown in START column in the Event Table on the instrument. The
Swell End time is time stamped with the time of the U
Rms(1/2)
that ended the event, as defined by
the threshold.
The Duration of a voltage swell is the time difference between the beginning and the end of the
swell. It is shown in Duration column in the Event Table on the instrument.
