ABB REF615 L - Section 13 IED physical connections; Protective earth connections; Binary and analog connections

11.6 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 110)
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 111)
Sequence components
The phase-sequence current components are calculated from the phase currents
according to:
I I I I
A B C0
3= + +( ) /
GUID-2319C34C-8CC3-400C-8409-7E68ACA4F435 V2 EN (Equation 112)
I I a I a I
A B C1
2
3= + ⋅ + ⋅( ) /
GUID-02E717A9-A58F-41B3-8813-EB8CDB78CBF1 V2 EN (Equation 113)
I I a I a I
A B C2
2
3= + ⋅ + ⋅( ) /
GUID-80F92D60-0425-4F1F-9B18-DB2DEF4C2407 V2 EN (Equation 114)
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= + +( ) /
GUID-49CFB460-5B74-43A6-A72C-AAD3AF795716 V2 EN (Equation 115)
U U a U a U
A B C1
2
3= + ⋅ + ⋅( ) /
GUID-7A6B6AAD-8DDC-4663-A72F-A3715BF3E56A V2 EN (Equation 116)
U U a U a U
A B C2
2
3= + ⋅ + ⋅( ) /
GUID-6FAAFCC1-AF25-4A0A-8D9B-FC2FD0BCFB21 V1 EN (Equation 117)
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= − ⋅( ) /
GUID-70796339-C68A-4D4B-8C10-A966BD7F090C V2 EN
(Equation 118)
U U a U
AB BC2
3= − ⋅( ) /
GUID-C132C6CA-B5F9-4DC1-94AF-FF22D2F0F12A V2 EN (Equation 119)
1YHT530004D05 D Section 11
General function block features
615 series 841
Technical Manual