ABB RELION REX640 Technical Manual page 1265

1MRS759142 F
5.11.9 Technical data
Table 1196: RESCPSCH Technical data
Characteristic
Operate time accuracy
5.12 Current reversal and weak-end infeed logic
CRWPSCH (ANSI 85 21CREV,WEI)
5.12.1 Identification
Function description
Current reversal and weak-end in-
feed logic
5.12.2 Function block
Figure 716: Function block
5.12.3 Functionality
The current reversal and weak-end infeed logic function CRWPSCH can be used
when the scheme communication logic DSOCPSCH requires additional logics to
operate correctly in all power system conditions.
In parallel feeder applications, the fault current direction on the healthy feeder can
change when the circuit breaker on the faulty feeder opens to clear the fault. This
can lead to an unwanted operation of the distance protection on the healthy parallel
feeder when DSOCPSCH is used with the permissive overreach scheme. The main
purpose of the current reversal logic is to prevent such unwanted operations.
The permissive communication schemes can operate only when the protection
in the remote terminal can detect the fault. This detection requires sufficient
minimum fault current. If such current is not available due to a too weak remote
end source, the weak-end infeed logic can be used to overcome the situation and
trip the remote end breaker.
REX640
Technical Manual
Value
±1.0 % of the set value or ±20 ms
IEC 61850 IEC 60617
identification identification
CRWPSCH CLCRW
Protection related functions
ANSI/IEEE C37.2
device number
85 21CREV,WEI
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