ABB RED650 - Page 419

BLOCK
VTSZ
WEIBLK1
WEIBLK2
CRL
t
tPickUpWEI
t
200 ms
CBOPEN
t
1500 ms
t
50 ms
t
200 ms
ECHO
OR
OR
AND
AND
AND
AND
OR
WEI = Echo
IEC05000123-3-en.vsd
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
WEIBLK1
WEIBLK2
CRL
OR
t
tPickUpWEI
t
200 ms
AND
CBOPEN
t
1500 ms
OR
AND
OR
t
50 ms
t
200 ms
WEI = Echo & Trip
ECHO
AND
AND
UPN<
U3P*
AND
AND
t
100 ms
OR
OR
OR
OR
AND
AND
t
15 ms
t
15 ms
t
15 ms
TRWEIL1
TRWEIL2
TRWEIL3
OR
T
R
W
E
I
UPP<
U3P*
UL1L2 <UPP<
UL2L3 < UPP<
UL3L1 < UPP<
UL1<UPN<
UL2 < UPN<
UL3 < UPN<
IEC00000551-TIFF.vsd
AND
IEC00000551-TIFF V4 EN-US
Figure 203: Simplified logic diagram for weak-end infeed logic — Echo&Trip
1MRK 505 394-UEN A Section 13
Scheme communication
Line differential protection RED650 2.2 IEC 413
Technical manual