MI 2792 PowerQ4 Plus
Theory and internal operation
107
Signalling voltage is calculated on a FFT spectrum of a 10-cycle interval. Value of mains
signalling voltage is measured as:
RMS value of a single frequency bin if signalling frequency is equal to spectral
bin frequency, or
RSS value of four neighboring frequency bins if signalling frequency differs from
the power system bin frequency (for example, a ripple control signal with
frequency value of 218,1 Hz in a 50 Hz power system is measured based on the
RMS values of 210, 215, 220 and 225 Hz bins).
Mains signalling value calculated every 10 cycle interval are used in alarm and
recording procedures. However, for EN50160 recording, results are aggregated
additionally on a 3s intervals. Those values are used for confronting with limits defined
in standard.
5.1.10 Flicker
Standard compliance:
IEC 61000-4-30 Class S (Section 5.3)
IEC
61000-4-15
Flicker is a visual sensation caused by unsteadiness of a light. The level of the
sensation depends on the frequency and magnitude of the lighting change and on the
observer.
Change of a lighting flux can be correlated to a voltage envelope on figure bellow.
¸¸
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
-400
-300
-200
-100
0
100
200
300
400
time (s)
voltage(V)
Figure 5.6: Voltage fluctuation
Flickers are measured in accordance with standard IEC 61000-4-15 “Flicker meter-
functional and design specifications”. It defines the transform function based on a
230V/60W lamp-eye-brain chain response. That function is a base for flicker meter
implementation and is presented on figure bellow.
