47113964.2.023РЭ
12
Table 8 Formulas for the calculation of parameters of three-phase four-wire system
Name of parameter
Designation
Formula
True RMS value of line-to-line
voltage
U
AB
U
BC
U
CA
(
)
,
1
1
0
2
∑
−
=
−
=
N
i
Bi
Ai
AB
u
u
N
U
(
)
,
1
1
0
2
∑
−
=
−
=
N
i
Ci
Bi
BC
u
u
N
U
(
)
∑
−
=
−
=
1
0
2
1
N
i
Ai
Ci
CA
u
u
N
U
Average value of line-to-line
voltage
U
AV
(
)
CA
BC
AB
AV
U
U
U
U
+
+
=
3
1
True RMS value of line-to-
neutral voltage
U
A
U
B
U
C
∑
−
=
=
1
0
2
1
N
i
PHi
PH
u
N
U
Average value of line-to-
neutral voltage
U
AVph
(
)
C
B
A
AVph
U
U
U
U
+
+
=
3
1
True RMS value of zero-
sequence voltage
U
0
(
)
∑
−
=
+
+
=
1
0
2
0
1
3
1
N
i
Ci
Bi
Ai
u
u
u
N
U
True RMS values of phase cur-
rent
I
A
I
B
I
C
∑
−
=
=
1
0
2
1
N
i
PHi
PH
i
N
I
Average values of phase cur-
rent
I
AV
(
)
C
B
A
AV
I
I
I
I
+
+
=
3
1
True RMS value of zero-
sequence current
I
0
(
)
∑
−
=
+
+
=
1
0
2
0
1
3
1
N
i
Ci
Bi
Ai
i
i
i
N
I
Active power, per phase
P
A
P
B
P
C
∑
−
=
⋅
=
1
0
1
N
i
PHi
PHi
PH
i
u
N
P
Active power of three-phase
system
P
C
B
A
P
P
P
P
+
+
=
Apparent power, per phase
S
A
S
B
S
C
PH
PH
PH
I
U
S
⋅
=
Apparent power of three-phase
system
S
2
2
2
2
2
2
C
B
A
C
B
A
I
I
I
U
U
U
S
+
+
⋅
+
+
=
Reactive power, per phase
Q
A
Q
B
Q
C
∑
−
=
⊥
⋅
=
1
0
1
N
i
PHi
PHi
PH
i
u
N
Q
Reactive power of three-phase
system
Q
C
B
A
Q
Q
Q
Q
+
+
=
Reactive power, per phase
(modulus)
Q
FA
Q
FB
Q
FC
2
2
PH
PH
FPH
P
S
Q
−
=
