ABB Relion 670 series - Page 138

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