ABB REL650 - Unblocking Scheme

12.1.3.5 Unblocking scheme
Set Unblock = Restart
(Loss of guard signal will give both trip and alarm
Choose NoRestart if only trip is required)
Set
tSecurity = 0.035 s
12.1.3.6 Intertrip scheme
Set Operation = Enabled
Set SchemeType = Intertrip
Set tCoord 50 ms (10 ms + maximal transmission time)
Set tSendMin = 0.1 s (0 s in parallel line applications)
Set Unblock = Disabled
Set tSecurity = 0.015 s
12.2 Current reversal and WEI logic for distance protection
3-phase ZCRWPSCH (85)
12.2.1 Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Current reversal and WEI logic for
distance protection 3-phase
ZCRWPSCH - 85
12.2.2 Application
12.2.2.1 Current reversal logic
If parallel lines are connected to common buses at both terminals, overreaching
permissive communication schemes can trip unselectable due to current reversal. The
unwanted tripping affects the healthy line when a fault is cleared on the parallel line. This
lack of security results in a total loss of interconnection between the two buses.
To avoid this kind of disturbances, a fault current reversal logic (transient blocking logic)
can be used.
1MRK 506 334-UUS A Section 12
Scheme communication
399
Application manual