MI 2892 Power Master
Theory and internal operation
162
50
100
150
200
Uc,k
Uh
1
Uh
2
Uh
3
Uh
4
Freqency
Uih
1
Uih2
Uih3
Figure 5.9: Illustration of harmonics / interharmonics subgroup for 50 Hz supply
The K factor is a factor that is developed to indicate the amount of harmonics that the load
generates. The K rating is extremely useful when designing electric systems and sizing components. It is
calculated as:
K - factor:
50
1
2
50
1
2
)
(
n
n
p
n
n
p
p
h
I
n
h
I
K
, p: 1,2,3
(64)
5.1.9
Signalling
Standard compliance: IEC 61000-4-30 Class A (Section 5.10)
Signalling voltage is calculated on a FFT spectrum of a 10/12-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 neighbouring frequency bins if signalling frequency differs from the power
system bin frequency (for example, a ripple control signal with frequency value of 218 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 10/12 cycle interval are used in alarm and recording procedures.
However, for EN50160 recording, results are aggregated additionally on a 3 s intervals. Those values are
used for confronting with limits defined in standard.
5.1.10
Flicker
Standard compliance: IEC 61000-4-30 Class A (Section 5.3)
IEC 61000-4-15 Class F3
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 below.
