Four Step Residual Overcurrent Protection, Zero, Negative Sequence Direction Ef4Ptoc - ABB REQ650 Applications Manual

1MRK 505 291-UEN A
6.6
Application manual
A
Z
~ A
Fault
IED
IEC09000025 V1 EN
Figure 58: Two parallel lines. Influence from parallel line to the through fault
current: I
The minimum theoretical current setting (Imin) will in this case be:
³ , ,
I m in M A X I ( I I )
fA fB M
EQUATION287 V1 EN
Where:
I and I have been described for the single line case.
fA fB
Considering the safety margins mentioned previously, the minimum setting (Is) is:
I ³
1.3.I
s m in
EQUATION288 V2 EN
Transformer inrush current shall be considered.
The setting of the protection is set as a percentage of the base current (IBase).
Operation: set the protection to On or Off.
IN>>: Set operate current in % of IBase. IBase is a global parameter valid for all
functions in the IED.
Four step residual overcurrent protection, zero,
negative sequence direction EF4PTOC
Line 1
C B
Z
L1
M
Z
L2
I
M
Line 2
M
Section 6
Current protection
Z
B ~
IEC09000025-1-en.vsd
(Equation 27)
(Equation 28)
115