ABB Relion 670 Series Technical Reference Manual page 138

Section 5
Differential protection
Trip unrestrained A
Trip unrestrained B
Trip unrestrained C
Pickup A
Pickup B
Pickup C
PU_A IdMinHigh
PU_B IdMinHigh
PU_C IdMinHigh
Internal fault
NegSeqDiffEn
External fault
Line energizing
nd
Diff curr A 2 harm
th
Diff curr A 5 harm
nd
Diff curr B 2 harm
th
Diff curr B 5 harm
nd
Diff curr C 2 harm
th
Diff curr C 5 harm
CrossBlockEn
ANSI05000295 V3 EN
Figure 54: Simplified block diagram
132
AND
OR
AND
OR
AND
OR
AND
tIdMinHigh
t
AND
OR
AND
OR
AND
OR
AND
OR
OR
Remembering that current values plotted above the characteristic formed by IdMin and
the dual slope in figure
summarized as follows:
OR
AND
OR
OR
AND
OR
OR
AND
OR
OR
OR
OR
AND
53 are said to give a pickup, the output logic can be
1MRK505222-UUS C
TRIP
OR
TR_A
TR_B
TR_C
ANSI05000295-3.vsd
Technical reference manual