ABB RELION REF615R, Technical Manual

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Peak-to-peak with peak backup
The peak-to-peak with peak backup measurement principle is selected with the
Measurement mode setting using the value "P-to-P+backup". It is similar to the peak-to-
peak mode, with the exception that it has been enhanced with the peak backup. In the peak-
to-peak with peak backup mode, the function starts with two conditions: the peak-to-peak
value is above the set pickup current or the peak value is above two times the set
Pickup
value . The peak backup is enabled only when the function is used in the DT mode in high
and instantaneous stages for faster operation.
12.6 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 44)
The residual voltage is calculated from the phase-to-ground voltages when the VT
connection is selected as “Wye” with the equation:
Vo V V V
A B C = + +
( )
GUID-4E68CD47-9DBB-4DAD-A092-BD69DA5863F3 V1 EN
(Equation 45)
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 46)
I I a I a I
A B C 1
2
3
= + ⋅ + ⋅
( ) /
GUID-02E717A9-A58F-41B3-8813-EB8CDB78CBF1 V2 EN
(Equation 47)
I I a I a I
A B C 2
2
3
= + ⋅ + ⋅
( ) /
GUID-80F92D60-0425-4F1F-9B18-DB2DEF4C2407 V2 EN
(Equation 48)
The phase-sequence voltage components are calculated from the phase-to-ground
voltages when
VT connection is selected as “Wye” with the formulae:
V V V V
A B C 0
3
= + +
( ) /
GUID-49CFB460-5B74-43A6-A72C-AAD3AF795716-ANSI V1 EN
(Equation 49)
1MRS240050-IB C
Section 12
General function block features
REF615R 619
Technical Manual