METREL Energy Master MI 2883, Instruction Manual

Page: 140 / 172

MI 2883 Energy Master Theory and internal operation
140

U
Swel l
– 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 S (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 5.10 and Figure 5.9),

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.
Figure 5.12:Voltage interrupts related screens on the instrument