ABB Relion 670 series, Technical Reference Manual

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AND
&
CRL
WEIBLK1
BLOCK
ECHO
WEI = Echo
ANSI09000032-2-en.vsd
0
200 ms
50 ms
0
0
200 ms
0
tPickUpWEI
ANSI09000032 V2 EN
Figure 406: Simplified logic diagram for weak-end infeed logic - Echo
With the WEI= Echo & Trip setting, the logic sends an echo according to the diagram
above. Further, it activates the TRWEI signal to trip the breaker if the echo conditions
are fulfilled and the neutral point voltage is above the set operate value for
3V0PU .
The voltage signal that is used to calculate the zero sequence voltage is set in the
ground fault function which is in operation.
CRL
BLOCK
WEIBLK1
TRWEI
CBOPEN
AND
AND
ECHO
WEI = Echo&Trip AND
3V0PU
AND
ANSI09000020-2-en.vsd
200 ms
0
0
200 ms
50 ms
0
100 ms
ANSI09000020 V2 EN
Figure 407: Simplified logic diagram for weak-end infeed logic - Echo & Trip
The weak-end infeed echo sent to the strong line end has a maximum duration of 200
ms. When this time period has elapsed, the conditions that enable the echo signal to be
sent are set to zero for a time period of 50 ms. This avoids ringing action if the weak-
end echo is selected for both line ends.
Section 13
1MRK505222-UUS C
Scheme communication
820
Technical reference manual