ABB RER615 - Page 829

Sequence components
The phase-sequence current components are calculated from the phase currents
according to:
I I I I
A B C0
3= + +( ) /
(Equation 91)
I I a I a I
A B C1
2
3= + ⋅ + ⋅( ) /
(Equation 92)
I I a I a I
A B C2
2
3= + ⋅ + ⋅( ) /
(Equation 93)
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 C0
3= + +( ) /
(Equation 94)
U U a U a U
A B C1
2
3= + ⋅ + ⋅( ) /
(Equation 95)
U U a U a U
A B C2
2
3= + ⋅ + ⋅( ) /
(Equation 96)
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 BC1
2
3= − ⋅( ) /
(Equation 97)
U U a U
AB BC2
3= − ⋅( ) /
(Equation 98)
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 99)
U U U U
B BC AB
= + −
( )
0
/ 3
(Equation 100)
1MRS758755 C
General function block features
REC615 & RER615
Technical Manual
829