MI 2892 Power Master
Theory and internal operation
167
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 (see Figure 5.12 and Figure 5.11),
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.
Voltage interrupt
Standard compliance: IEC 61000-4-30 Class A (Section 5.5)
Measuring method for voltage interruptions detection is same as for dips and swells, and is described in
previous sections.
The Interrupt Threshold is a percentage of nominal voltage defined in CONNECTION menu. Interrupt
Hysteresis is difference in magnitude between the Interrupt start and Interrupt end thresholds. The
interrupt threshold can be set by the user according to the use. Instrument event evaluation in Event
table screen depends on Connection type:
On single-phase system (1W), a voltage interruption begins when the U
Rms(1/2)
voltage falls below
the voltage interruption threshold and ends when the U
Rms(1/2)
value is equal to, or greater than,
the voltage interruption threshold plus the hysteresis (see Figure 5.12 and Figure 5.11),
On poly-phase systems (2W, 3W, 4W, Open Delta) two different view can be used for evaluation
simultaneously:
o
Group view
with selected
ALL
INT
view: a voltage interruption begins when the
U
Rms(1/2)
voltages of all channels fall below the voltage interruption threshold and
ends when the U
Rms(1/2)
voltage on any one channel is equal to, or greater than, the
voltage interruption threshold plus the hysteresis.
o
Phase view Ph.: a voltage interrupt begins when the U
Rms(1/2)
voltage of one channel
fall below the interrupt threshold, and ends when the U
Rms(1/2)
voltage is equal to or
above the interrupt threshold plus the hysteresis voltage, on the same phase.
