Functions
6-140 7SA6 Manual
C53000-G1176-C156-2
6.8.1 Method of Operation
SwitchingOnand
Off
The teleprotection function can be switched on and off by means of the parameter
3201 FCT Telep. E/F, or via the system interface (if available) and via binary inputs
(if these are allocated). The switched state is saved internally (refer to Figure 6-77)
and secured against loss of auxiliary supply. It is only possible to switch on from the
source where previously it had been switched off from. To be active, it is necessary
that the function is switched on from all three switching sources.
X
Figure 6-77 Switching on and off of the signal transmission logic
6.8.1.1 Directional Comparison Scheme
The following procedure is suited for both conventional and digital transmission media.
Principle The directional comparison scheme is a permissive scheme. In Figure 6-78 the oper-
ation scheme
is shown.
When the earth fault protection recognizes a fault in the forward direction, it initially
sends a permissive signal to the opposite line end. If a permissive signal is also re-
ceived from the remote end, the trip signal is passed on to the tripping relay. Accord-
ingly it is a prerequisite for fast tripping that the fault is recognized in the forward direc-
tion at both line ends.
The send signal can be prolonged by T
S
(parameter setting). The prolongation of the
sendsignalonlycomesintoeffectiftheprotectionhasalreadyissuedatripcommand.
This ensures that the permissivesignal releasesthe opposite line end even if the earth
fault is very rapidly cleared by a different independent protection.
≥1
EF TeleprotOFF
EF Telep. OFF
ON
OFF
FCT Telep. E/F
EF Teleprot.ON
S
R
System port: EF Telep. OFF
S
R
„1“
3201
System port: EF Telep. ON
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