ABB RET670 Applications Manual page 403

1MRK504116-UUS C
Application manual
IBase: Base current in primary A. This current is used as reference for current setting.
If possible to find a suitable value the rated current of the protected object is chosen.
OpModeSel: This parameter can be set to 2 out of 3 or 1 out of 3. The setting controls
the minimum number of phase currents that must be larger than the set operate current
Pickup for operation. Normally this parameter is set to 1 out of 3and will thus detect all
fault types. If the protection is to be used mainly for multi phase faults, 2 out of 3
should be chosen.
Pickup: Set operate current in % of IBase.
MultPU: The operate current can be changed by activation of the binary input
MULTPU to the set factor MultPU.
Meshed network without parallel line
The following fault calculations have to be done for three-phase, single-phase-to-
ground and two-phase-to-ground faults. With reference to figure 179, apply a fault in B
and then calculate the current through-fault phase current I
done using the minimum source impedance values for Z
impedance values for Z
B
A
Z
~ A
IED
ANSI09000022 V1 EN
Figure 179: Through fault current from A to B: I
Then a fault in A has to be applied and the through fault current I
calculated, figure 180. In order to get the maximum through fault current, the minimum
value for Z and the maximum value for Z
B
in order to get the maximum through fault current from A to B.
I
fB
Z
L
Fault
have to be considered.
A
Section 3
IED application
. The calculation should be
fB
and the maximum source
A
B
Z
~
B
ANSI09000022-1-en.vsd
fB
has to be
fA
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