ABB rec670 Applications Manual

en99000044_ansi.vsd
Strong
source
LINE 1
LINE 2
A:1
A:2
B:1
B:2
A B
Weak
source
CLOSED
CLOSED
OPEN
CLOSED
FAULT
ANSI99000044 V1 EN-US
Figure 196: Current distribution for a fault close to B side when breaker at B1 is
opened
When the breaker on the parallel line operates, the fault current on the healthy line is
reversed. The IED at B2 recognizes the fault in forward direction from reverse
direction before breaker operates. As IED at B2 already received permissive signal
from A2 and IED at B2 is now detecting the fault as forward fault, it will immediately
trip breaker at B2. To ensure that tripping at B2 should not occur, the permissive
overreaching function at B2 needs to be blocked by IRVL till the received permissive
signal from A2 is reset.
The IED at A2, where the forward direction element was initially activated, must reset
before the send signal is initiated from B2. The delayed reset of output signal IRVL
also ensures the send signal from IED B2 is held back till the forward direction
element is reset in IED A2.
15.5.2.2 Weak-end infeed logic
M15285-6 v5
Figure
197 shows a typical system condition that can result in a missing operation.
Note that there is no fault current from node B. This causes that the IED at B cannot
detect the fault and trip the breaker in B. To cope with this situation, a selectable weak-
end infeed logic is provided for the permissive overreaching scheme.
en99000054_ansi.vsd
LINE 1
A B
Strong
source
Weak
source
CLOSEDCLOSED
FAULT
ANSI99000054 V1 EN-US
Figure 197: Initial condition for weak-end infeed
15.5.3 Setting guidelines
IP15042-1 v1
M13933-4 v5
The parameters for the current reversal and weak-end infeed logic for residual
overcurrent protection function are set via the local HMI or PCM600.
Section 15 1MRK 511 401-UUS A
Scheme communication
482 Bay control REC670 2.2 ANSI
Application manual

ABB rec670 Specifications

General

Brand	ABB
Model	rec670
Category	Control Unit
Language	English