Calibration of analog inputs
SEMOD54417-293 v5
Measured currents and voltages used in the CVMMXN function can be calibrated
to get 0.5 class measuring accuracy. This is achieved by amplitude and angle
compensation at 5, 30 and 100% of rated current and voltage. The compensation
below 5% and above 100% is constant and linear in between, see example in
figure
263.
IEC05000652 V2 EN-US
Figure 263: Calibration curves
The first current and voltage phase signal, in the group signals will be used as
reference. The amplitude and angle compensation will be used for other related
input signals.
Low pass filtering
SEMOD54417-233 v4
In order to minimize the influence of the noise signal on the measurement it is
possible to introduce the recursive, low pass filtering of the measured values for P,
Q, S, U, I and power factor. This will make slower measurement response to the
step changes in the measured quantity. Filtering is performed in accordance with
the following recursive formula:
1MRK 505 394-UEN A Section 15
Monitoring
Line differential protection RED650 2.2 IEC 527
Technical manual
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