ABB Relion 670 Series Applications Manual page 394

Section 14
Scheme communication
14.1.3.6 Intertrip scheme
Operation
Set
SchemeType
Set
Set tCoord
tSendMin
Set
Unblock
Set
tSecurity
Set
14.2 Current reversal and Weak-end infeed logic for distance
protection 3-phase ZCRWPSCH (85)
14.2.1 Identification
Function description
Current reversal and weak-end
infeed logic for distance protection
3-phase
14.2.2 Application
14.2.2.1 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.
The unwanted operations that might occur can be explained by looking into Figure
Figure 188. Initially the protection A2 at A side will detect a fault in forward direction and send a
communication signal to the protection B2 at remote end, which is measuring a fault in reverse
direction.
388
Enabled
=
Intertrip
=
50 ms (10 ms + maximal transmission time)
= 0.1 s (0 s in parallel line applications)
Disabled
=
= 0.015 s
IEC 61850
identification
ZCRWPSCH
IEC 60617 ANSI/IEEE C37.2
identification device number
- 85
1MRK 511 358-UUS A
M13869-62 v4
IP15751-1 v4
M15073-1 v5
IP15023-1 v1
M13895-4 v5
187 and
Application manual