Siemens siprotec 7SA6 User Manual page 312

Functions
!$
A8UÃXrhxÃDsrrq
OFF
ECHO only
„1"
" $ "D‚HvÃUryrƒ…‚‡
ECHO and TRIP
I
E
3I
0
EF Pickup
EF OFF/BLOCK
from receiving logic
(Fig. 6-72 or 6-74)
1324 >EF BlkEcho
CB open (3pole)
Figure 6-78 Logic diagram of the echo function for the earth fault protection with teleprotection
6-130
circuit breaker at the non-feeding line end is open, this delay of the echo signal is not
required. The echo delay time may then be bypassed. The circuit breaker switching
state is provided by the central information function control. (refer to Section 6.20).
The echo impulse is then transmitted (alarm output "(&+2 6,*1$/"), the duration of
which can be set with the parameter 7ULS (;7(16,21.
Note:
The "(&+2 6,*1$/" (F.No. 4246) must be separately assigned to the output relay
that is used for signal transmission, as it is not included in the transmit signal
"() 7HOH 6(1'".
After transmission of the echo impulse, the transmission of a new echo is prevented
for at least 20 ms. This prevents from repetition of an echo after the line has been
switched off.
The echo function is not required for the blocking scheme, and is therefore ineffective.
≥1
≥1
S Q
&
R
Echo release by
the distance prot.
(ref. to Fig. 6-59
!$! Uv€rÃ9@G6`Ã
≥1
&
&
&
Q
R
!$" U…vƒÃ@YU@ITDPIÃ
T 0
≥1
4246
T
20 0
S
ms
&
C53000-G1176-C133-1
ECHO SIGNAL
7SA6 Manual