Sequence components
The phase-sequence current components are calculated from the phase currents
according to:
I
I
I
I
A
B
C
0
3
=
+
+
(
) /
(Equation 208)
I
I
a I
a
I
A
B
C
1
2
3
=
+ ⋅
+
⋅
(
) /
(Equation 209)
I
I
a
I
a I
A
B
C
2
2
3
=
+
⋅
+ ⋅
(
) /
(Equation 210)
The phase-sequence voltage components are calculated from the phase-to-earth
voltages when
VT connection is selected as “Wye” with the equations:
U
U
U
U
A
B
C
0
3
=
+
+
(
) /
(Equation 211)
U
U
a U
a
U
A
B
C
1
2
3
=
+ ⋅
+
⋅
(
) /
(Equation 212)
U
U
a
U
a U
A
B
C
2
2
3
=
+
⋅
+ ⋅
(
) /
(Equation 213)
When
VT connection is selected as “Delta”, the positive and negative phase
sequence voltage components are calculated from the phase-to-phase voltages
according to the equations:
U
U
a
U
AB
BC
1
2
3
=
−
⋅
(
) /
(Equation 214)
U
U
a U
AB
BC
2
3
=
−
⋅
(
) /
(Equation 215)
The phase-to-earth voltages are calculated from the phase-to-phase voltages when
VT connection is selected as "Delta" according to the equations.
U
U
U
U
A
AB
CA
=
+
−
(
)
0
3
/
(Equation 216)
U
U
U
U
B
BC
AB
=
+
−
(
)
0
/ 3
(Equation 217)
1MRS757644 H
General function block features
620 series
Technical Manual
1167
