ABB REL650 series Technical Manual page 192

Section 6
Impedance protection
186
ZCVPSOF can be activated externally from input BC and thus setting AutoInit is
bypassed.
The function is released during a settable time tSOTF.
The function can be blocked by activating the input BLOCK.
BLOCK
BC
AutiInit=Enabled
ZACC
IA
IB
IC
VA
UILevel detector
VB
VC
IphPickup
UVPickup
Mode = Impedance
Mode = VILevel
Mode = VILvl&Imp
ANSI09000398 V2 EN
Figure 87: Simplified logic diagram for Automatic switch onto fault logic, voltage and
current based.
OR
t
AND
t
tSOFT
tDLD
deadLine
tDuration
SOTFUILevel
t
AND
AND
OR
AND
1MRK 506 335-UUS A
15
t
AND
OR
ANSI09000398-2-en.vsd
Technical manual
TRIP