ABB RED650 - Page 105

Start L1
Start L3
Start L2
St L1 IdMinHigh
St L3 IdMinHigh
St L2 IdMinHigh
Diff curr L1 2
nd
harm
Diff curr L3 2
nd
harm
Diff curr L2 2
nd
harm
Diff curr L3 5
th
harm
Diff curr L2 5
th
harm
Diff curr L1 5
th
harm
Line energizing
AND
AND
AND
CrossBlockEn
External fault
Internal fault
OR
tIdMinHigh
t
OR
OR
OR
OR
OR
OR
Trip unrestrained L3
Trip unrestrained L1
Trip unrestrained L2
OR
OR
OR
OR
OR
AND
AND
IEC05000295-3-en.vsd
TRIP
TRL1
TRL2
TRL3
OR
OR
OR
OR
OR
OR
AND
AND
AND
AND
AND
AND
AND
NegSeqDiffEn
IEC05000295 V3 EN-US
Figure 36: Simplified block diagram
Remembering that current values plotted above the characteristic formed by IdMin
and the dual slope in Figure 35 are said to give a start, the output logic can be
summarized as follows:
•
A start in one phase, gives a trip under the condition that the content of the 2
nd
and the 5
th
harmonic is below the set level for these harmonics in the phase
with start, if CrossBlockEn = OFF. If CrossBlockEn = ON, then all phases
with their start signals set, must be free of their respective harmonic block
signals; otherwise no trip command is issued. Otherwise it is blocked as long
1MRK 505 394-UEN A Section 6
Differential protection
Line differential protection RED650 2.2 IEC 99
Technical manual