Unblocking Scheme - ABB REL650 Applications Manual

1MRK 506 334-UUS A
12.1.3.5
12.1.3.6
12.2
12.2.1
12.2.2
12.2.2.1
Application manual

Unblocking scheme

Unblock Restart
Set =
(Loss of guard signal will give both trip and alarm
Choose
tSecurity
Set = 0.035 s
Intertrip scheme
Operation Enabled
Set =
Set SchemeType = Intertrip
tCoord
Set 50 ms (10 ms + maximal transmission time)
tSendMin
Set = 0.1 s (0 s in parallel line applications)
Unblock Disabled
Set =
Set tSecurity = 0.015 s
Current reversal and WEI logic for distance protection
3-phase ZCRWPSCH (85)
Identification
Function description
Current reversal and WEI logic for
distance protection 3-phase
Application
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.
NoRestart if only trip is required)
IEC 61850 IEC 60617
identification identification
ZCRWPSCH
Section 12
Scheme communication
ANSI/IEEE C37.2
device number
- 85
399