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30
NV10P - Manual - 01 - 2015
CHARACTERISTICS
Direct
Frequency. The measure of period is taken from voltage inputs.
Samples are processed by means DFT (Discrete Fourier Transform) algorithm and the phase and
amplitude of fundamental are computed:
Input voltages
U
L1
,
U
L2
,
U
L3
Residual voltage
U
E
Calculated
By means vector addition of direct measures the following are calculated (RMS value of fundamen-
tal components):
Calculated residual voltage
U
EC
Negative sequence voltage:
U
2
- Fundamental components of phase-to-phase voltages:
U
12
,
U
23
,
U
31
[1]
Nota 1 La misura delle tre tensioni concatenate è disponibile solo per le versioni con ingressi da sensori
•
•
•
•
•
•
F. a i
(Hz)
u
L1
u
L2
U
L1
U
L2
ACQUISITION
VT
≈
≈
u
L3
U
L3
U
L1
U
L2
U
L3
≈
f
UL2
T
(Hz)
f
UL1
T
(Hz)
f
UL3
T
F. a i
(Hz)
u
L1
u
L2
U
L1
U
L2
ACQUISITION
VT
≈
≈
u
L3
U
L3
U
L1
U
L2
U
L3
≈
f
UL2
T
(Hz)
f
UL1
T
(Hz)
f
UL3
T
U L 1 - e n . a i
ACQUISITION
u
L1
,
u
L2
,
u
L3
DFT
TV
≈
U
L1
,
U
L2
,
U
L3
(
E
n
)
U L 1 - e n . a i
ACQUISITION
u
L1
,
u
L2
,
u
L3
DFT
TV
≈
U
L1
,
U
L2
,
U
L3
(
E
n
)
U E - e n . a i
(
U
En
)
(
U
En
)
ACQUISITION
u
E
DFT (fundamental)
TV
≈
U
E
DFT (3rd harmonic)
U
E3H
U E - e n . a i
(
U
En
)
(
U
En
)
ACQUISITION
u
E
DFT (fundamental)
TV
≈
U
E
DFT (3rd harmonic)
U
E3H
U E C . a i
U
L1
U
EC
=
U
L1
+
U
L2
+
U
L3
U
EC
U
L3
U
L2
(
U
En
)
U E C . a i
U
L1
U
EC
=
U
L1
+
U
L2
+
U
L3
U
EC
U
L3
U
L2
(
U
En
)
U 2 . a i
U
L1
U
2
U
2
= (
U
L1
+ e
-j120°
U
L 2
+ e
+j120°
U
L 3
)
U
L3
U
L2
e
-j120°
= -
√3
j
1
2
2
-
e
+j120°
= -
√3
j
1
2
2
+
(
u
n
)
U 2 . a i
U
L1
U
2
U
2
= (
U
L1
+ e
-j120°
U
L 2
+ e
+j120°
U
L 3
)
U
L3
U
L2
e
-j120°
= -
√3
j
1
2
2
-
e
+j120°
= -
√3
j
1
2
2
+
(
u
n
)
U 1 2 . a i
U
L1
U
12
=
U
L1
-
U
L2
U
12
U
23
U
31
U
23
=
U
L2
-
U
L3
U
31
=
U
L3
-
U
L1
U
L2
U
L2
U
L3
U
L1
U
L3
(
U
n
)
(
U
n
)
(
U
n
)
U
L1
U
12
U
31
U
23
U
L3
U
L2
U 1 2 . a i
U
L1
U
12
=
U
L1
-
U
L2
U
12
U
23
U
31
U
23
=
U
L2
-
U
L3
U
31
=
U
L3
-
U
L1
U
L2
U
L2
U
L3
U
L1
U
L3
(
U
n
)
(
U
n
)
(
U
n
)
U
L1
U
12
U
31
U
23
U
L3
U
L2
