Functions
2.7 Teleprotection for Distance Protection (optional)
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
188
Transmission channels
At least one channel in each direction is required for the signal transmission. For example, fibre optic connec-
tions or voice frequency modulated high frequency channels via communication cables, power line carrier or
microwave radio links can be used for this purpose.
As an alternative, digital communication lines connected to one of the protection data interfaces can be used
for signal transmission. This connection can, for example, consist of a fibre-optic cable, a communication
network or dedicated cables (control cables or twisted phone wires). In this case, the send and receive signals
must be assigned to fast command channels of the protection data interface (DIGSI matrix).
The pilot wire comparison, that is exclusively applied to short lines, enables the user to operate a pilot wire pair
(pilot wires or control wires) with direct current to guarantee the exchange of information between the line ends.
Also the reverse interlocking operates with DC control signals.
7SD5 allows the transmission of phase-selective signals as well. This has the advantage that a reliable 1-pole
automatic reclosure can be carried out reliably even if two 1-phase faults occur on different lines in the system.
The signal transmission schemes are also suited for three terminal lines (teed feeders). In this case, a signal
is transmitted from each of the three ends to each of the others in both directions.
If disturbances occur in the transmission path, the teleprotection supplement may be blocked without affecting
the normal distance protection grading. The measuring reach control (enable zone Z1B) can be transmitted to
the internal automatic reclose function or via the binary input
„>Enable ARzones“
to an external reclosure
device. With conventional signal transmission schemes, the disturbance is signalled by a binary input, with
digital communication it is automatically detected by the protection device.
2.7.2
Method of Operation
Activation and Deactivation
The teleprotection function can be switched on and off by means of the parameter
2101
FCT Telep. Dis.
,
or via the system interface (if available) and via binary input (if this is allocated). The switched state is saved
internally (refer to Figure 2-82) 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 not
switched off from one of the three switching sources.
Figure 2-82
Activation and deactivation of teleprotection
