ABB Relion 611 Series, Technical Manual

Page: 495 / 536

9.6 Calculated measurements
Calculated residual current and voltage
The residual current is calculated from the phase currents according to equation:
Io I I I
A B C
= − + +
( )
GUID-B9280304-8AC0-40A5-8140-2F00C1F36A9E V1 EN
(Equation 51)
The residual voltage is calculated from the phase-to-earth voltages when the VT
connection is selected as “Wye” with the equation:
Uo U U U
A B C
= + +
( ) / 3
GUID-03909E83-8AA3-42FF-B088-F216BBB16839 V1 EN
(Equation 52)
Sequence components
The phase-sequence current components are calculated from the phase currents
according to:
I I I I
A B C 0
3
= + +
( ) /
GUID-2319C34C-8CC3-400C-8409-7E68ACA4F435 V2 EN
(Equation 53)
I I a I a I
A B C 1
2
3
= + ⋅ + ⋅
( ) /
GUID-02E717A9-A58F-41B3-8813-EB8CDB78CBF1 V2 EN
(Equation 54)
I I a I a I
A B C 2
2
3
= + ⋅ + ⋅
( ) /
GUID-80F92D60-0425-4F1F-9B18-DB2DEF4C2407 V2 EN
(Equation 55)
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
= + +
( ) /
GUID-49CFB460-5B74-43A6-A72C-AAD3AF795716 V2 EN
(Equation 56)
U U a U a U
A B C 1
2
3
= + ⋅ + ⋅
( ) /
GUID-7A6B6AAD-8DDC-4663-A72F-A3715BF3E56A V2 EN
(Equation 57)
U U a U a U
A B C 2
2
3
= + ⋅ + ⋅
( ) /
GUID-6FAAFCC1-AF25-4A0A-8D9B-FC2FD0BCFB21 V1 EN
(Equation 58)
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
= − ⋅
( ) /
GUID-70796339-C68A-4D4B-8C10-A966BD7F090C V2 EN
(Equation 59)
U U a U
AB BC 2
3
= − ⋅
( ) /
GUID-C132C6CA-B5F9-4DC1-94AF-FF22D2F0F12A V2 EN
(Equation 60)
1MRS757454 D
Section 9
General function block features
611 series 489
Technical Manual