ABB Relion 670 Series Technical Reference Manual page 127

1MRK 505 208-UEN B
TRZONE
tripZoneA from Bay01
tripZoneA from Bay02
tripZoneA from Baynn
SensDiffOper = On
ENSENS
SensIinBlock
SensOperLevel
BLKST
ZA Diff Algorithm
I
d
I
in
CheckZoneSup = Off
CZTrip
BLOCK
Operation = On
RSTTRIP
DiffTripOper = Latched
IEC06000072 V1 EN
Figure 55: Simplified Zone internal trip logic for one phase
Technical reference manual
OR
3s
I a
t
in
a>b
b
I
a
d
a>b
b
OR
tTripHold
AND t
AND
Dual monitoring of differential protection status is available. The first monitoring
feature operates after settable time delay when differential current is higher than
the user settable level. This feature can for example be used to design automatic
reset logic for previously described open CT detection feature. The second
monitoring feature operates immediately when the busbar through-going current is
OR
tSensDiff
t
AND
OR
AND
OCTBlock
S
AND
AND
R
Differential protection
TREXTZ
TREXTBAY
TRSENS
TRIPLX
OR
OR
AND
TRIP
OR
ZATrip-cont.
en06000072.vsd
Section 5
121