KBR multimess D9-PQ
20144 EDEBD
A0228-5023-1_EN
85
Harmonics / Interharmonics
The determination of the harmonics and interharmonics interval values
displayed using the methods of the IEC61000-4-30 Class A standard based on
10/12 period values.
The multimess D9-PQ recognizes for all voltage and current channels, respec-
tively, the harmonics up to the 50th ordinal. To evaluate the interharmonics,
harmonic subgroups are created. 50 subgroups are recorded for all current and
voltage channels.
harmonic
subgroup n+1
harmonic
order
DFT
output
n
n+1
n+2
n+3
interharmonic
subgroup n+2,5
Example:
„IH1“ is the first interharmonics group and evaluated the frequency range from
5 Hz to 45 Hz.
The harmonics for n = 0...50 are calculated.
Voltage harmonics (standardized, 10/12 periods):
nom
N
n
N
n
k
k
n
U
C
U
∑
+
⋅
−
⋅
=
−
⋅
=
1
1
2
12
/
10
2
1
Current harmonics:
∑
+
⋅
−
⋅
=
−
⋅
=
1
1
2
12
/
10
2
1
N
n
N
n
k
k
n
C
I
Measurement data – measurement methods