ABB RELION 670 Series Technical Manual page 170

Section 6
Differential protection
BLKUNRES
IdUnre
IDMAG_A
IBIAS
BLOCK
BLKRES
Cross Block
from B or C
OpCrossBlock=Yes
ANSI07000020 V3 EN-US
Figure 58: Generator differential logic diagram 1
Neg.Seq. Diff
Current
Contributions
OpNegSeqDiff=On
IBIAS
Constant
BLKNSSEN
BLKNSUNR
BLOCK
PU_A
PU_B
PU_C
ANSI07000021 V2 EN-US
Figure 59: Generator differential logic diagram 2
164
a
b>a
b
AND
2nd and
5th
Harmonic
AND
Internal/
External
Fault
discrimin
ator
a
b>a
b
OR
AND
AND
NOT
OR
AND
AND
AND
en07000021_ansi.vsd
1MRK 502 066-UUS B
TRIPUNRE_A
PU_A
TRIPRES_A
Cross Block
To B or C
ANSI07000020-3-en.vsd
INTFAULT
TRNSSENS
Technical manual