User's Manual

Setting up a Measurement
Nominal/Limit Values 5
5-7
EN50160
In this section you set the limits for the statistical evaluation of the voltage measurement.
nominalandlimits_en50160.bmp
Slow voltage variations are often caused by load variations in the distribution network.
Enter the mains frequency
limit values for 95 % and for 100 % of the measurement time.
The evaluation is based on the 10 min mean values.
Fast voltage variations are often caused by load switching in the distribution network.
Enter the limit value for 95 % of the measurement time. The evaluation is based on half
cycle rms values or full cycle rms values updated every half cycle (whatever is
configured in the D - S - I panel).
Enter the mains frequency limit values for 95 % and for 100 % of the measurement time.
Please note that in unsynchronized “island” networks, the class for frequency variations
is different: 95 % instead of 99.5 % of the measurement period for interconnected
systems. A selection is provided.
Voltage fluctuations cause changes in luminance of lighting systems, which can create a
visual phenomenon which is called Flicker. The limit value for the long-term Flicker Plt
is defined in the standard EN50160 as 1.0. This is the perceptibility threshold of the
visual sensation.