Meshed Network With Parallel Line - ABB REL650 Applications Manual

1MRK 506 334-UUS A
7.2.3.2
Application manual
I
F
A
Z
~
A
IED
ANSI10000275 V1 EN
Figure 84: Fault current: I
The IED setting valuePickup is given in percentage of the primary base current value,
IBase. The value for Pickup is given from this formula:
Is
= ×
Pickup 100
IBase
ANSIEQUATION1147 V1 EN

Meshed network with parallel line

In case of parallel lines, the influence of the induced current from the parallel line to the
protected line has to be considered. One example is given in figure
are connected to the same busbars. In this case the influence of the induced fault current
from the faulty line (line 1) to the healthy line (line 2) is considered together with the two
through fault currents I
fA
parallel line for the IED in figure
open.
A fault in C has to be applied, and then the maximum current (I
the healthy line (this applies for single-phase-to-ground and two-phase-to-ground faults)
is calculated.
Z
L
Fault
F
and I mentioned previously. The maximal influence from the
fB
85 will be with a fault at the C point with the C breaker
Section 7
Current protection
B
Z
~
B
ANSI10000275-1-en.vsd
85 where the two lines
) seen from the IED on
M
(Equation 102)
177