Measured Value Acquisition And Processing - Siemens SIMEAS R-PMU Manual

6

6.1 Measured Value Acquisition and Processing

6.1 Measured Value Acquisition and Processing
AC signals Sam pling
D C signals Sam pling
Binary signals Sam pling
Figure 6-1 Measured value acquisition and processing
Sampling
AC and process signals of a data acquisition unit are digitized with a constant sampling rate of
192 sample values per nominal cycle. The binary signals are also read with a constant sampling
rate of 2 kHz and stored.
For further processing, the frequency is calculated first and then used to resample the sample
values.
This is not applicable for process values. Process values are zero-frequency values and are
therefore processed separately.
Nominal cycle duration
The nominal cycle duration T
With a nominal system frequency of, e. g., 50 Hz, the nominal cycle duration is 20 ms. The cur-
rently measured cycle may differ from the nominal cycle.
42
C alculation of half- cycle
rm s values
Frequency calculation
R esam pling
M ean value calculation
is the reciprocal of the nominal system frequency f
n
Digital Fault Recorder, SIMEAS R-PMU, Manual
Trigger value
M easured and
trigger values
M easured and
FF T
trigger values
M easured value
M easured and
trigger values
M easured value
M easured and
trigger values
: T
n
E50417-H1076-C360-A5, Release 10.2012
= 1/f .
n n