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3
3.2 Formulas and Calculation of Derived Quantities
45
Power Meter SICAM P 7KG7750/55, Manual
E50417-B1076-C340-A6, Edition 09.2013
Line Derived
Quantity
Formula
Note
18 System
frequency
P
T
N
f
=
Refer to note 1
19
Active energy demand
0
1
>
=
∑
=
P
for
P
W
ν
ν
The active energy demand will
be calculated every second.
20
Active energy supply
0
1
<
=
∑
=
P
for
P
W
ν
ν
The active energy supply will
be calculated every second.
21
Active energy without sign
∑
=
=
1
ν
ν
P
W
Calculation without sign
22
Active energy net demand
∑
=
=
1
ν
ν
P
W
Calculation with sign
23
Asymmetrical voltage U or
current I
M
G
V
=
Refer to note 2
Range is 0 to
∞
, avoid division
by 0!
24 THD
voltage,
current
1
1
−
=
M
M
THD
tot
Refer to note 3
25
Harmonics
From Fourier transformation