User's Manual

PC Software for 1740 Series
PQ Log Feature Reference
43
Voltage Variations
The column Maximum value displays the maximum and minimum deviation in
percentage in relation to the nominal voltage. In the 95 %-value column, the upper and
lower limits indicate that 95% of all measurement values are between the positive and the
negative values.
Note
The absolute value of the voltage deviation is used to calculate the 95 %
value. However, the information about the sign is lost. Therefore, there is
only one 95 %-value.
With symmetrical limit values (example,
± 10 %), the 95 %-value is given
under Maximum, if the maximum interval value is not below the 95 %-
value; otherwise, the maximum interval value is given. And, the 95 %-value
is given under Minimum, if the minimum is not above the 95 %-value;
otherwise, the minimum interval value is given.
With unsymmetrical limit values (example, +6 % / - 10 %), the individual
measurement values are scaled according to the limit values, and the 95 %-
value is recalculated based on the scaled values. This takes into account
that, example, 103 % V
n
have a greater impact than 97 % V
n
, if the limit
value is +6 % / -10 %
The number of interruptions per phase, number per phase is given,
although there is no 95 %-value given.
Events (Voltage Dips and Swells)
Details such as the number per phase are displayed. There is no 95 %-value given.
Harmonics
In this field, amplitude of the harmonic, interharmonic, or thd which has the highest
95 %-value, that is closest to the limit value, or exceeds it the most, is given for each
phase. If the most critical result is the same for all three phases, only one column is
displayed; otherwise, two or three are displayed.
Only those harmonics/interharmonics, or thd can be analyzed that have a defined limit
value, and that have actually been measured. The EN 50160 only defines limit values up
to the 25
th
harmonic. Use the cumulative frequency representation for more detailed
examination. Select a limit value file with limit values for all harmonics, for example
50160_61000-2-2.gwd.
Flicker
The maximum values and the 95 %-values are given for each phase.
Unbalance
The maximum value and the 95 %-value are given.
Signaling Voltages
The signaling voltage of each phase is given that has the most critical 95 %-value. If the
most critical signaling voltage is the same for all three phases, only one column is
displayed; otherwise, two or three are displayed.