ABB Relion 650 Series Technical Manual page 363

1MRK 506 326-UUS B
11.5.2 Functionality
The Current reversal and weak-end infeed logic for residual overcurrent protection ECRWPSCH
(85) is a supplement to Scheme communication logic for residual overcurrent protection ECPSCH
(85).
To achieve fast fault clearing for all ground faults on the line, the directional ground-fault
protection function can be supported with logic that uses communication channels.
The 650 series IEDs have for this reason available additions to scheme communication logic.
If parallel lines are connected to common busbars at both terminals, overreaching permissive
communication schemes can trip unselectively due to fault current reversal. This unwanted
tripping affects the healthy line when a fault is cleared on the other line. This lack of security can
result in a total loss of interconnection between the two buses. To avoid this type of disturbance,
a fault current reversal logic (transient blocking logic) can be used.
Permissive communication schemes for residual overcurrent protection can basically operate only
when the protection in the remote IED can detect the fault. The detection requires a sufficient
minimum residual fault current, out from this IED. The fault current can be too low due to an
opened breaker or high-positive and/or zero-sequence source impedance behind this IED. To
overcome these conditions, weak-end infeed (WEI) echo logic is used.
11.5.3 Function block
V3P*
BLOCK
IFWD
IREV
WEIBLK1
WEIBLK2
LOVBZ
CBOPEN
CRL
ANSI09000006 V1 EN-US
Figure 192: ECRWPSCH (85) function block
11.5.4 Signals
Table 292: ECRWPSCH (85) Input signals
Name
V3P
BLOCK
IFWD
IREV
WEIBLK1
Table continues on next page
Line distance protection REL650
Technical manual
ECRWPSCH (85)
IRVL
TRWEI
ECHO
CR
ANSI09000006-1-en.vsd
Type
GROUP
SIGNAL
BOOLEAN
BOOLEAN
BOOLEAN
BOOLEAN
© Copyright 2011 ABB Power Grids. All rights reserved
Default Description
- Three phase group signal for voltage inputs
0 Block of function
0 A signal that indicates a forward fault has been detected and will
block tripping if there was a pre-existing reverse fault condition
(IREV)
0 A signal that indicates a reverse fault has been detected and
activates current reverasl logic
0 Block of WEI Logic
Section 11
Scheme communication
M13928-3 v4
M13928-6 v2
M13928-8 v3
M13930-3 v5
PID-1622-INPUTSIGNALS v5
357