Siemens siprotec 7SA6, Manual

Page: 281 / 876

Functions
6-91
7SA6 Manual
C53000-G1176-C156-2
Figure 6-49 Switching on and off of the teleprotection
6.6.1.1 Permissive Underreach Transfer Trip with Pick-up (PUTT)
The following procedure is suited for conventional transmission media.
Principle Figure 6-50 shows the operation scheme of the permissive underreach transfer trip
scheme. In the case of a fault inside zone Z1, the transfer trip signal is sent to the op-
posite line end. The signal received at that end causes the tripping if the corresponding
protection function picked up. The transmitted signal may be prolonged by T
S
(setta-
ble in address
2103A Send Prolong.
), to compensate for possible differences in
the pick-up times at the two line ends. The distance protection is set in such a way that
the first zone reaches up to approximately 85 % of the line length. In three-end lines
Z1 is also set to approx. 85 % of the shorter line section, at least, however, up to the
T-point.
The overreach zone Z1B is not relevant for this signal transmission scheme, but it can
be controlled by the automatic reclosure (see also Subsection 6.14.1).
Figure 6-50 Operation scheme of the permissive underreach transfer trip method via pickup
Sequence Figure 6-51 shows the logic diagram of the permissive underreach transfer trip
scheme for one line end.
≥
1
>Dis.Telep.OFF
Dis Telep. off
ON
OFF
FCT Telep. Dis.
>Dis.Telep. ON
S
R
System port: Dis.Telep.OFF
S
R
„1“
2101
System port: Dis.Telep.ON
A B
Z1(A)
Z1(B)
PICKUP(A)
PICKUP(B)
Z1
PU
(B)
(B)
T
S
T1
&
≥
1
trip
transm.
rec.
further
zones
Z1
PU
(A)
(A)
T
S
T1
&
≥
1
trip
transm.
rec.
further
zones
PICKUP(A)
PICKUP(B)