User's Manual

1760
Reference Manual
5-8
The maximum permissible number of voltage events (dips, swells, and interruptions) is
defined here. This number is used in the EN50160 overview graph to scale the height of
the events bar.
Unbalance occurs if the 3 phase voltage system is not symmetric (that is, phase angles
differ from the nominal 120° or magnitudes of the phase voltages differ from each other).
This is the limit for 95 % of the 10 min values during the measurement period.
EN50160 hxx
nominalandlimits_enhxx.bmp
Harmonics are components of the supply voltage with integer multiple (order) of the
fundamental of the supply voltage. A limit value can be assigned for each harmonic with
orders between 2 and 25, including THD (total harmonic distortion). The statistical
evaluation of the harmonics is based on 10 minute mean values.
Rapid Voltage Changes
Rapid voltage changes are fast transitions from one steady state to the other. The Steady
voltage tolerance defines the allowable variation for a steady state. The voltage must stay
within the tolerance band for at least the Minimum steady time for the state to be
classified as steady. The Minimum Voltage difference is the minimum required voltage
step, which triggers a rapid voltage change event. The voltage difference is either
computed from two consecutive steady states or from the difference between the
maximum values in the unsteady time and the steady state. The latter complies to the
Norwegian FoL requirement. Select the desired behavior with the Minimum Voltage