MI 2792 PowerQ4 Plus
Theory and internal operation
113
Figure 5.9: Synchronization and aggregation of 10 cycle intervals
For each aggregation interval instrument computes average value for measured
quantity. Depending from the quantity, this can be RMS (root means square) or
arithmetical average. Equations for both averages are shown below.
RMS average
N
j
j
RMS
A
N
A
1
2
1
Where:
A
RMS
– quantity average over given aggregation interval
A – 10-cycle quantity value
N – number of 10 cycles measurements per aggregation interval.
(28)
Arithmetic average:
N
j
j
avg
A
N
A
1
1
Where:
A
avg
– quantity average over given aggregation interval
A – 10-cycle quantity value
N – number of 10 cycles measurements per aggregation interval.
(29)
In the next table averaging method for each quantity is specified:
Table 5.3: Data aggregation methods
Group
Value
Aggregation method
U
Rms
RMS
THD
U
RMS
Voltage
U
cf
Arithmetic
I
Rms
RMS
THD
I
RMS
Current
I
cf
Arithmetic
Frequency
f Arithmetic
Power
P Arithmetic
