KBR multimess D9-PQ
20144 EDEBD
A0228-5023-1_EN
82
THD – PWHD – K factor
Total harmonic content, calculated using the following formula in accordance
with IEC61000-4-7.
Calculating the THD values of the voltages and signal sampling:
The voltage and current inputs are filtered with an anti-aliasing filter and
digitized with a 24-bit converter.
The sampling rate is at the nominal frequency 40.96 kSamples/s.
The aggregation of the measurements is based on IEC61000-4-30 for Class A
devices.
RMS values of the voltages and currents, min. / max. values
U eff / I eff
The interval value of the voltage or current is the mean of the RMS values of the
length of the selected interval.
U min / max; I min / max
Per measurement period, the highest and lowest 10 ms voltage or current RMS
value is saved in addition to the average.
Flicker levels Pst / Plt
The Short term flicker levels Pst (10 min) and Long term flicker levels Plt (2 h)
are calculated for the star and delta voltages. Pst and Plt are defined in EN
61000-4-15: 2010.
The measuring interval of the Pst is set to 10 minutes fix and is independently
from the free intervall.
Formula for Plt calculation:
P
P
lt
st i
i
=
=
∑
1
12
3
1
12
3
,
Measurement data – measurement methods