User manual

UMG 96RM
6
General
Explanations of the measured values
Measured value
• Ameasuredvalueisaeffectivevaluewhichisformedoveraperiod(measuringwindow)of200ms.
• Ameasuringwindowis10periodsinthe50Hznetworkand12periodsinthe60Hznetwork.
• Ameasuringwindowhasastarttimeandanendtime.
• Theresolutionbetweenthestarttimeandendtimeisapproximately2ns.
• Theaccuracyofthestarttimeandendtimedependsontheaccuracyoftheinternalclock.
(Typically +- 1 minute/month)
• Inordertoimprovetheaccuracyoftheinternalclock,itisrecommendedthattheclockinthedeviceiscompared
with a time service and reset.
n Mean time / seconds
0 5
1 10
2 15
3 30
4 60
5 300
6 480
7 600
8 900
Mean value of measured value
• Foreachmeasuredvalue,aslidingmeanvalueiscalculatedovertheselectedaveragingtime.
• Themeanvalueiscalculatedevery200ms.
• Youcantakethepossibleaveragingtimesfromthetable.
Max. value of measured value
• Themax. value of the measured value is the largest measured value which has occurred since the last deletion.
Min. value of measured value
• Themin. value of the measured value is the lowest measured value which has occurred since the last deletion.
Max. value of mean value
• Themax. value of the mean value is the largest mean value which has occurred since the last deletion.
Nominal current, voltage, frequency
• Thelimitvaluesforeventsandtransientsaresetbythenominalvalueinpercentage.
Nominal current I
rated
• TheIratedisthenominalcurrentofthetransformersandisrequiredforcalculationoftheK-factor.
Peak value negative
• Highestnegativesamplingvaluefromthelast200msmeasuringwindow..
Peak value positive
• Highestpositivesamplingvaluefromthelast200msmeasuringwindow.
Crest factor
• Thecrestfactordescribestherelationbetweenthepeakvalueandeffectivevalueofaperiodicquantity.Itservesas
a characteristic value for general description of the curve form of a periodic quantity. The distortion factor is another
example of a quantity for characterization of the difference from the pure sinusoidal form.
• Example
A sinusoidal change voltage with an effective value of 230 V has a peak value of approx. 325 V.
The crest factor is then 325 V / 230 V =1.414 .