ABB Relion 670 series, Technical Reference Manual

Page: 825 / 1232

Connect the necessary signal from the autorecloser for blocking of the directional
comparison scheme, during a single-phase autoreclosing cycle, to the BLOCK input of
the directional comparison module.
13.6.2.2 Fault current reversal logic
The fault current reversal logic uses a reverse directed element, connected to the input
signal IREV, which recognizes that the fault is in reverse direction. When the reverse
direction element is activated the output signal IRVL is activated which is shown in
Figure
405 . The logic is now ready to handle a current reversal without tripping. The
output signal IRVL will be connected to the block input on the permissive
overreaching scheme.
When the fault current is reversed on the healthy line, IRV is deactivated and IRVBLK
is activated. The
tDelayRev timer delays the reset of the output signal. The signal
blocks operation of the overreach permissive scheme for residual current and thus
prevents unwanted operation caused by fault current reversal.
tPickUp
Rev
AND
tDelay
Rev
BLOCK
IREV
IFWD
IRVL
tPickUp
Rev
Drawing2.vsd
0 0
10ms
0
0
ANSI09000031 V1 EN
Figure 405: Simplified logic diagram for current reversal
13.6.2.3 Weak-end infeed logic
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 406 and Figure 407 .
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
406 and Figure
407 . 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 ground
fault function that is in operation.
1MRK505222-UUS C
Section 13
Scheme communication
819
Technical reference manual