ABB RED650, Technical Manual

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AND
BLOCK
IRVBLK
t
tPickUpRev
t
tPickUpRev
t
10 ms
IRV
CurrRev = On
t
tDelayRev
IRVL
IEC09000031-4-en.vsd
IEC09000031 V4 EN-US
Figure 211: Simplified logic diagram for current reversal
13.5.6.3 Weak-end infeed logic
M13929-24 v10
The weak-end infeed function can be set to send only an echo signal ( WEI=Echo )
or an echo signal and a trip signal ( WEI=Echo & Trip ). The corresponding logic
diagrams are depicted in Figure 212 and Figure 213 .
The weak-end infeed logic uses normally a reverse and a forward direction
element, connected to WEIBLK2 via an OR-gate. If neither the forward nor the
reverse directional measuring element is activated during the last 200 ms, the
weak-end infeed logic echoes back the received permissive signal as shown in
Figure
212 and Figure 213 . The weak-end infeed logic also echoes the received
permissive signal when CBOPEN is high (local breaker opens) prior to faults
appeared at the end of line.
If the forward or the reverse directional measuring element is activated during the
last 200 ms, the fault current is sufficient for the IED to detect the fault with the
earth fault function that is in operation.
1MRK 505 394-UEN A
Section 13
Scheme communication
Line differential protection RED650 2.2 IEC 427
Technical manual