ABB RELION 611 Series Technical Manual page 222

Section 4
Protection functions
216
GUID-1AB5D686-3B9C-413F-9D0A-215BFCA224B4 V1 EN
Figure 100: Phase-segregated bus differential protection based on high-
impedance principle
CT secondary winding resistances (R
also shown in Figure 101.
Figure 101 demonstrates a simplified circuit consisting only of one incoming and
outgoing feeder. To keep it simple, the voltage-dependent resistor (R
The wiring resistances are presented as total wiring resistances R
R is the maximum wiring resistance concerning all incoming feeder
m1
sets, whereas R
outgoing feeder sets.
The lower part of Figure 101
system and no CT saturation.
) and connection wire resistances (R
in
is the maximum wiring resistance concerning all
m2
shows the voltage balance when there is no fault in the
1MRS757454 D
/2) are
m
) is not included.
u
and R .
m1 m2
611 series
Technical Manual