MI 2883 Energy Master
Theory and internal operation
137
Nom
RMS
Nom
Nom
RMS
i
RMS
i
Over
U
U
U
U
U
U
U
)
12
/
10
(
)
12
/
10
(
),
12
/
10
(
,
if
if
(54)
Aggregation is performed on the end of recording interval as:
%
1
2
,
Nom
n
i
i
Under
Nom
Under
U
n
U
U
U
(55)
%
1
2
,
Nom
n
i
i
Over
Nom
Over
U
n
U
U
U
(56)
Underdeviation and overdeviation parameters may be useful when it is important to
avoid, for example, having sustained undervoltages being cancelled in data by
sustained overvoltages.
Note:
Underdeviation and Overdeviation parameters are always positive values.
5.1.12
Voltage events
Measurement method
Standard compliance: IEC 61000-4-30 Class S (Section 5.4)
The basic measurement for event is U
Rms(1/2)
.
U
Rms(1/2)
is value of the RMS voltage
measured over 1 cycle, commencing at a fundamental zero crossing and refreshed
each half-cycle.
The cycle duration for
U
Rms(1/2)
depends on the frequency, which is determined by the
last 10/12-cycle frequency measurement. The
U
Rms(1/2)
value includes, by definition,
harmonics, interharmonics, mains signalling voltage, etc.
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
-375
-250
-125
0
125
250
375
Dip Duration
U
Rms(1/2)
1-cycle long
U (Voltage)
U
Rms(1/2)
Dip Threshold
Dip Hysteresis
Figure 5.9:U
Rms(1/2)
1-cycle measurement
