MI 2892 Power Master
Theory and internal operation
166
Voltage dip
Standard compliance: IEC 61000-4-30 Class A (Sections 5.4.1 and 5.4.2)
The Dip Threshold is a percentage of Nominal voltage defined in CONNECTION menu. The Dip Threshold
and Hysteresis can be set by the user according to the use. Dip Hysteresis is difference in magnitude
between the Dip start and Dip end thresholds. Instrument event evaluation in Event table screen
depends on Connection type:
On single-phase system (Connection type: 1W), a voltage dip begins when the U
Rms(1/2)
voltage
falls below the dip threshold, and ends when the U
Rms(1/2)
voltage is equal to or above the dip
threshold plus the hysteresis voltage (see Figure 5.12 and Figure 5.11),.
On poly-phase systems (Connection type: 2W, 3W, 4W, Open Delta) two different views can be
used for evaluation simultaneously:
o
Group view
with selected ALL
INT
view (in compliance with IEC 61000-4-30 Class A):
a dip begins when the U
Rms(1/2)
voltage of one or more channels is below the dip
threshold and ends when the U
Rms(1/2)
voltage on all measured channels is equal to or
above the dip threshold plus the hysteresis voltage.
o
Phase view Ph. (for troubleshooting): a voltage dip begins when the U
Rms(1/2)
voltage of
one channel falls below the dip threshold, and ends when the U
Rms(1/2)
voltage is equal to
or above the dip threshold plus the hysteresis voltage, on the same phase.
Figure 5.13: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:
