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30
NC2 0 - Manual - 01 - 2015
FUNCTION CHARACTERISTICS
Direct
Frequency. The measure of period is taken preferably from voltage inputs; when all voltage are
missing the input current are employed.
Samples are processed by means DFT (Discrete Fourier Transform) algorithm and the phase and
amplitude of fundamental are computed:
Phase currents (RMS value of the fundamental and harmonic components) I
L1
,
I
L2
,
I
L3
Phase currents (RMS value) I
L1RMS
,
I
L2RMS
,
I
L3RMS
Phase voltages (RMS value of the fundamental component) U
L1
,
U
L2
,
U
L3
Unbalanced neutral current (RMS value of the fundamental component) I
N
•
•
•
•
•
F.ai
(Hz)
(Hz)
u
L1
u
L2
U
L1
U
L2
ACQUISITION
VT
≈
≈
u
L3
U
L3
I
L1
I
L2
CT
I
L3
≈
i
L1
i
L2
≈
≈
i
L3
≈
f
T
f
T
F.ai
(Hz)
(Hz)
u
L1
u
L2
U
L1
U
L2
ACQUISITION
VT
≈
≈
u
L3
U
L3
I
L1
I
L2
CT
I
L3
≈
i
L1
i
L2
≈
≈
i
L3
≈
f
T
f
T
IL1.ai
(I
n
)
ACQUISITION
i
L1
, i
L2
, i
L3
DFT
CT
≈
DFT
DFT
I
L1
, I
L2
, I
L3
I
L1-2nd
, I
L2-2nd
, I
L3-2nd
I
L1-11th
, I
L2-11th
, I
L3-11th
IL1.ai
(I
n
)
ACQUISITION
i
L1
, i
L2
, i
L3
DFT
CT
≈
DFT
DFT
I
L1
, I
L2
, I
L3
I
L1-2nd
, I
L2-2nd
, I
L3-2nd
I
L1-11th
, I
L2-11th
, I
L3-11th
IL1RMS.ai
(I
n
)
I
L1RMS
I
L2RMS
I
L3RMS
I
L1
I
L1RMS
= √(I
L1
2
+ I
L1-2nd
2
+... I
L1-11th
2
)
I
L2RMS
= √(I
L2
2
+ I
L2-2nd
2
+... I
L2-11th
2
)
I
L3RMS
= √(I
L3
2
+ I
L3-2nd
2
+... I
L3-11th
2
)
I
L2
I
L3
IL1RMS.ai
(I
n
)
I
L1RMS
I
L2RMS
I
L3RMS
I
L1
I
L1RMS
= √(I
L1
2
+ I
L1-2nd
2
+... I
L1-11th
2
)
I
L2RMS
= √(I
L2
2
+ I
L2-2nd
2
+... I
L2-11th
2
)
I
L3RMS
= √(I
L3
2
+ I
L3-2nd
2
+... I
L3-11th
2
)
I
L2
I
L3
UL1.ai
ACQUISITION
u
L1
, u
L2
, u
L3
DFT
VT
≈
U
L1
, U
L2
, U
L3
(E
n
)
UL1.ai
ACQUISITION
u
L1
, u
L2
, u
L3
DFT
VT
≈
U
L1
, U
L2
, U
L3
(E
n
)
IN.ai
(I
Nn
)
ACQUISITION
i
N
DFT
CT
≈
I
N
I
N
IN.ai
(I
Nn
)
ACQUISITION
i
N
DFT
CT
≈
I
N
I
N
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