NOVAR 2100/2200 Operating Manual
n ........... number of samples per measurement cycle ( 1280 / 1152 )
Ui
1
, Ii
1
… sampled values of voltage and current
The data for the longer measurements are aggregated from these measurement cycles.
4.5.3 Harmonics and THD Evaluation Method
Entire spectrum of harmonic components and THD is evaluated periodically from 10 / 12 mains cycles
long signal according to IEC 61000-4-7 ed.2 as harmonic sub-groups (H
sg
).
Following quantities are evaluated :
Harmonic components of voltage and current up to 50
th
order :
Uih
1
, Iih
1
( i …. order of harmonic component )
Absolute angle of voltage harmonic component phasor :
φUih
1
Current harmonic component phasor angle relative to phasor Ufh
1
:
φIih
1
Relative angle between correspondent voltage and current phasors :
Δφi
1
Total harmonic distortion of voltage :
THD
U
1
=
1
U
1
h
1
√
∑
i
=
2
40
Uih
1
2
∗
100 %
Total harmonic distortion of current :
THD
I
1
=
1
I
1
h
1
√
∑
i
=
2
40
Iih
1
2
∗
100 %
4.5.4 Power and Power Factor and Evaluation Method
Power and power factor values are calculated continuously from the sampled signals according to
formulas mentioned below. The formulas apply to basic type of connection – 1Y3.
Active power :
P
1
=
∑
k
=
1
40
U
k
,1
∗
I
k
,1
∗
cosΔφ
k
,1
Reactive power :
Q
1
=
∑
k
=
1
40
U
k
,1
∗
I
k
,1
∗
sinΔφ
k
,1
where : k … harmonic order index, odd components only
U
k,1
, I
k,1
… the k
th
harmonic components of voltage and current ( of phase 1 )
Δφ
k,1
... angle between the k
th
harmonic components U
k,1
, I
k,1
( of phase 1 )
( these harmonic components of U and I are evaluated from each measurement cycle )
Apparent power :
S
1
=
U
1
∗
I
1
Power factor :
PF
1
=
|
P
1
|
S
1
Three-phase active power: :
∑
P
=
P
1
∗
3
Three-phase reactive power :
∑
Q
=
Q
1
∗
3
Three-phase apparent power :
∑
S
=
S
1
∗
3
57
