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SICAM Q80 7KG8080
Power Quality Recorder SICAM Q80 7KG8080, System manual
E50417-H1076-C420-A2, Release 12.01.2015
3.2.3
Rapid fluctuations of the RMS-value
Rapid changes in the RMS-values of voltage and current are recorded in the
curve plots
. For this purpose, a
patented procedure called
Transitional Recording
is used.
Fig 3-1 Curve plot of a voltage outage
The figure shows a voltage outage with data reduction. The crosses mark the sampled points of which the reduced
curve plot consists.
A "
transition
" always refers to a change from a stationary amplitude state to a new state, where
state
can also mean
a stretch of constant increase or decrease in amplitude. By comparing the slopes appearing within the curve to be
reduced, sudden changes of the curve's course can be detected. The procedure is designed to limit the resulting
curve plot's maximum deviation from the original signal.
The classic algorithm has been slightly modified for
SICAM Q80 7KG8080
. Thus, within a tolerance band of 5 %
around the nominal voltage, the algorithm works at its default accuracy of
1,5 %
, while outside of this band it works at
twice that level, namely
0,75 %
. The values can be edited via the user interface. As a result, events such as voltage
dips are represented in very high precision while within the uninteresting "passing" region, the data is strongly
reduced. By extending the data format to 64 bits the bufferable time range between two points is increased so that for
a constant voltage, an obligatory data point must be recorded only after approx. 23 hours.
These steps increase the achievable reduction factor al the way to
1:20,000
without sacrificing relevant information.
Ideally, if the network is free from disturbances, there would be
eight data points per week
: one per day plus the
initial point. By contrast, any disturbances are recorded with time resolution of one-half period. In any case:
no
threshold values
need to be set.