ABB Relion 670 Series Technical Reference Manual page 288

Section 9
Multipurpose protection
Bin input: BLKUC1TR
Selected current
StartCurr_UC1
Operation_UC1=On
Bin input: BLKUC1
IEC05000750 V1 EN
Figure 145: Simplified internal logic diagram for built-in first undercurrent step that is, UC1 (step UC2 has
the same internal logic)
Selected voltage
StartVolt_OV1
Operation_OV1=On
BLKOV1
IEC05000751 V1 EN
Figure 146: Simplified internal logic diagram for built-in first overvoltage step OV1 (step OV2 has the same
internal logic)
282
a
b>a
b
AND
DEF time
selected
a
a>b
b
AND
Inverse time
selected
AND
DEF
DEF
OR
Inverse
1MRK 505 208-UEN B
TRUC1
STUC1
en05000750.vsd
BLKTROV1
TROV1
AND
STOV1
en05000751.vsd
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