Thytronic NG10 - Page 27

FUNCTION CHARACTERISTICS
27
NG10 - Manual - 04 - 2022
Direct
Samples are processed by means DFT (Discrete Fourier Transform) algorithm and the phase and
amplitude of fundamental are computed:
• Phase currents I
L1H
, I
L2H
, I
L3H
, I
L1L
, I
L2L
, I
L3L
,
• Residual current I
E
Calculated
By means vector addition of direct measures the following are calculated (RMS value of fundamen-
tal components):
• Phase compensated currents - side H I
L1cH
, I
L2cH
, I
L3cH
and side L I
L1cL
, I
L2cL
, I
L3cL
• Stabilization currents (87 element) I
SL1
, I
SL2
, I
SL
• Differential currents (87 element) I
dL1
, I
dL2
, I
dL3
IL1.ai
(I
nH
, I
nL
)
i
L1H
, i
L2H
, i
L3H
i
L1L
, i
L2L
, i
L3L
DFT
≈
I
L1H
, I
L2H
, I
L3H
I
L1L
, I
L2L
, I
L3L
ACQUISITION
IE.ai
(I
En1
, I
En2
)
ACQUISITION
i
E1
, i
E2
DFT
≈
I
E1
, I
E2
ILC.ai
i
L1H
i
L3H
i
L2H
i
L1L
i
L3L
i
L2L
i
L1cH
, i
L2cH
, i
L3cH
I
L1cH
, I
L2cH
, I
L3cH
i
L1cL
, i
L2cL
, i
L3cL
i
L1cH =
i
L1H·
P
H·
M
H·
C
H
i
L2cH =
i
L2H·
P
H·
M
H·
C
H
i
L3cH =
i
L3H·
P
H·
M
H·
C
H
i
L1cL =
i
L1L·
P
L·
M
L·
C
L
P
H
,P
L
: Polarity matching
M
H
,M
L
: Magnitute matching
C
H
,C
L
: Phase and Ciclic sequence and zero sequence matching
i
L2cL =
i
L2L·
P
L·
M
L·
C
L
i
L3cL =
i
L3L·
P
L·
M
L·
C
L
(I
nref
)
DFT
I
L1cL
, I
L2cL
, I
L3cL
(I
nref
)
DFT
ISL.ai
i
L1cH
,i
L1cL
i
L2cH
,i
L2cL
i
L3cH
,i
L3cL
i
SL1
, i
SL2
, i
SL3
I
SL1
, I
SL2
, I
SL3
i
SL1 =
{i
L1cH+
sign[i
L1cL·
i
L1cH
]
·
i
L1cL
}/2
i
SL2 =
{i
L2cH+
sign[i
L2cL·
i
L2cH
]
·
i
L2cL
}/2
i
SL 3 =
{i
L3cH+
sign[i
L3cL·
i
L3cH
]
·
i
L3cL
}/2
sign[a·b]=+1 se a·b ≥ 0
sign[a·b]=-1 se a·b < 0
(I
nref
)
DFT
IdL.ai
i
L1cH
,i
L1cL
i
L2cH
,i
L2cL
i
L3cH
,i
L3cL
i
dL1
, i
dL2
, i
dL3
I
dL1
, I
dL2
, I
dL3
i
dL1 =
i
L1cH+
i
L1cL
i
dL2 =
i
L1cH+
i
L1cL
i
dL3 =
i
L1cH+
i
L1cL
(I
nref
)
DFT