ABB RED650 Technical Manual page 419

1MRK 505 394-UEN A
Line differential protection RED650 2.2 IEC
Technical manual
BLOCK
VTSZ
OR
WEIBLK 1
tPickUpWEI
CRL
t
200 ms
WEIBLK 2
t
1500 ms
CBOPEN
t
WEI = Echo
IEC05000123 V3 EN-US
Figure 202: Simplified logic diagram for weak-end infeed logic — Echo
When an echo function is used in both IEDs (should generally be avoided), a
spurious signal can be looped round by the echo logics. To avoid a continuous
lock-up of the system, the duration of the echoed signal is limited to 200 ms.
An undervoltage criteria is used as an additional tripping criteria, when the tripping
of the local breaker is selected, setting WEI = Echo&Trip. With this setting the
Echo and Trip are working in parallel as in logic shown in Figure 203.
BLOCK
VTSZ
OR
WEIBLK1
tPickUpWEI
CRL
t
200 ms
WEIBLK2
t
1500 ms
CBOPEN
t
U3P*
UL1<UPN<
UL2 < UPN<
UL3 < UPN<
UPN<
U3P*
UL1L2 <UPP<
UL2L3 < UPP<
UL3L1 < UPP<
UPP<
WEI = Echo & Trip
IEC00000551-TIFF V4 EN-US
Figure 203: Simplified logic diagram for weak-end infeed logic — Echo&Trip
AND
AND
AND
OR
AND
AND
AND
OR
100 ms
OR
AND
t
OR
OR
OR
Section 13
Scheme communication
50 ms 200 ms
t
OR t
AND
IEC05000123-3-en.vsd
50 ms 200 ms
OR AND
t
t
AND
15 ms
AND
t
15 ms
AND
t
15 ms
AND
t
ECHO
ECHO
OR
TRWEIL1
TRWEIL2
TRWEIL3
IEC00000551-TIFF.vsd
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