ABB RELION REX640 Technical Manual page 1279

1MRS759142 F
Weak-end infeed (WEI) logic
The WEI logic is recommended to be used only in the permissive schemes.
Setting guidelines for current reversal logic
Reversal reset time : This setting can be set to the maximum reset time of the
communication channel. A minimum setting of 40 ms is recommended. A long
Reversal reset time setting increases the security against unwanted tripping, but
delays the fault clearing if the fault develops from one feeder to involve the other.
However, the probability of this type of fault is small.
Reversal time : Set the start delay reversal time below 80 percent of the breaker
operate time, but to a minimum of 20 ms.
Setting guidelines for Weak-end infeed (WEI) logic
The WEI logic returns the received carrier signal with the ECHO output when it
receives the carrier signal (CR) if no fault has been detected by the forward and
reverse directional measuring elements and the duration is longer than the
time coordination time delay setting. To prevent the spurious carrier receive signals
from activating the WEI logic and causing unwanted communication, the
time setting can be set to "0.010 s".
5.13.7 Signals
5.13.7.1 RCRWPSCH Input signals
Table 1206: RCRWPSCH Input signals
Name
URES
BLOCK
BLK_IRV
BLK_WEI1
BLK_WEI2
IRV
FF
Table continues on the next page
REX640
Technical Manual
Do not use the WEI function at both feeder ends. It can only be enabled
at the weak end.
Type
SIGNAL
BOOLEAN
BOOLEAN
BOOLEAN
BOOLEAN
BOOLEAN
BOOLEAN
Protection related functions
Default Description
- Residual voltage
0=False Block signal for acti-
vating the blocking
mode
0=False Block of current rever-
sal function
0=False Block of WEI Logic
0=False Block of WEI logic due
to operation of other
protections
0=False Activation of current
reversal logic
0=False Block of trip from
WEI logic through
fuse-failure function
Wei Crd
Wei Crd
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